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HomeMy WebLinkAbout20000846 Ver 1_Stormwater Info_20060101Michael Baker Jr., Inc. A Unit of Michael Baker Corporation 19 October 2001 P.O. Box 12259 Pittsburgh, Pennsylvania 15231-0259 (412) 269-4600 Ms. Cyndi Karoly FAX (412) 269-2747 North Carolina Department Office Location: of Environmental and Natural Resources Airport Office Park, Building 3 420 Rouser Road 1617 Mail Service Central Coraopolis, Pennsylvania 15108 Raleigh, NC 27699-1617 Subject: Piedmont Triad Airport Authority - Stormwater Management Plan Version 1.0 Update Number 1 Dear Ms. Karoly: Enclosed is Update Number 1 to the Stormwater Management Plan Version 1.0. This update should be posted in your copy of the Stormwater Management Plan along with this transmittal letter. Your copy of the Plan are numbers 1 and 2. This update provides a final copy of Section 7.0 Storm Water Plan for Deep River (Randleman Lake) Watershed. Section 7.0 includes: 1. Certificate of Adoption 2. Resolution Adopting Randleman Lake Storm Water Management Plan 3. Pages 7-1 through 7-8 4. Deep River High Point Watershed Map As updates are published, a copy will be forwarded to your attention. Sincerely, BAKER AND ASSOCIATES Allan R. Berenbrok, P.E. Project Manager OCT 3 0 2001 ?^ f r U.. ... LI'' .. i Attachments ARB/sam cc: Mr. Mickie Elmore 0 k CERTIFICATE OF ADOPTION I certify that I am the Secretary of the Piedmont Triad Airport Authority and that at a meeting duly called and held on August 21, 2001, the attached resolution and accompanying "Sto= Water Plan for Deep River (Randleman Lake) Watershed" were duly adopted by said Authority. This the '71 day of August, 2001 Authority F t ? F OCT 3 0 2001 r 4k Resolution Adopting Randleman Lake Storm Water Management Plan WHEREAS, under 15A NCAC 213; 0251 of the North Carolina Code of Regulations, local governments having land in the Randleman Lake Watershed, including the Authority, must adopt a comprehensive storm water management plan, that is approved by the North Carolina Environmental Management Commission, for the portion of their jurisdiction that is within the watershed boundary and; WHEREAS, the staff of the Authority has developed a proposed plan in accordance with the state regulations entitled A Storm Water Plan for the Deep River (Randleman Lake) Watersheds @ (the AProposed Plan@), a copy of which has been furnished to each of the members of the Authority, and such plan has been approved on behalf of the North Carolina Environmental Management Commission by its Water Quality Committee; and WHEREAS, the adoption and implementation of the Proposed Plan would fulfill the Authority's obligations under the applicable regulations, would promote good watershed management of the portion of the Randleman Lake Watershed that is within the Authority's jurisdiction, and would help to improve water quality within the Randleman Lake Watershed and the Randleman Lake Reservoir now under construction; NOW, THEREFORE, BE IT RESOLVED by the Piedmont Triad Airport Authority that the Proposed Plan is hereby approved and adopted as the Randleman Lake Storm Water Management Plan of the Authority in accordance with 15A NCAC 2B. 0251 and that the officers and staff of the Authority are hereby directed to Implement such plan in accordance with its terms. August, 2001 Section 7 Resolution Randleman Lake 7.0 Storm Water Plan for Deep River (Randleman Lake) Watershed Under 15A NCAC 2B. 0251 (4), local governments with land use authority within the proposed Randleman Lake Watershed are required to adopt comprehensive storm water management plans for the portion of the watershed that is under their jurisdiction. The Deep River, High Point Watershed, as described in this SWMP, and as shown on the Watershed Map that appears at the end of this Section, is a part of the larger Randleman Lake Watershed, and PTAA is therefore required by 15A NCAC 2B.0251(4) to adopt a comprehensive storm water plan for the portion of the Airport that is within this area. This Section 7 sets forth the plan the PTAA has adopted. It is intended as a supplement to the rest of this SWMP, and applies only to land within the Deep River, High Point Watershed that PTAA presently owns or acquires in the future. The regulations describe six separate components to be included in the plan. The applicable requirements of the regulations, and the corresponding provisions of PTAA's plan, are as follows: Evaluation of Existing Land Use Regulation: (a) Evaluation of existing land use within Oak Hollow Lake subwatershed, High Point Lake subwatershed and Deep Riverl subwatershed in the Randleman Lake Watershed with recommendations that show how overall built-upon area (for existing and future development) for each subwatershed can be minimized and high intensity land uses can be targeted away from surface waters and sensitive areas. Oak Hollow Lake subwatershed is defined as all land areas draining to Oak Hollow Lake. High Point Lake subwatershed is defined as all land areas draining to High Point Lake, East Fork Deep River and West Fork Deep River from Oak Hollow Lake Dam. Deep River 1 subwatershed is defined as all land areas draining to the Deep River from High Point Lake Dam to Freeman Mill Dam. This evaluation shall be done by the local governments having jurisdiction in those watersheds, working in cooperation with the PTRWA. Goal: Evaluate and possibly modify existing land use plans and development patterns to achieve better protection of the Randleman Lake Watershed. August, 2001 Section 7-Page 1 Randleman Lake Action Items: The Watershed Map appearing at the end of this Section identifies three separate zones within the Deep River, (Randleman Lake) Watershed, for planning purposes, as follows: ¦ Zone 1: Zone 1 consists of the Runway Protection Zone (RPZ) in the approach to existing Runway 5R, as shown on the map, plus some adjoining land outside of the RPZ. PTAA owns most of the land within Zone 1 as shown on the map. The land that is owned by PTAA within Zone 1 is presently undeveloped, except for an instrument landing system, other navigational aids, and a gravel service road. ¦ Zone 2: Zone 2 consists of all of the land that is owned by PTAA within the Randleman Lake Watershed that is not within Zone 1 or Zone 3. Zone 2 includes major airport facilities, including a portion of Runway 14-32 and associated taxiways, an air cargo building and major aircraft hangars. PTAA is presently relocating its Maintenance Building within Zone 2. ¦ Zone 3: Zone 3 is located at the southwest end of proposed Runway 5L-23R. It will consist of the portion of the RPZ for the proposed runway north of the right- of-way of U.S. 421 and east of the right-of-way for U.S. 68, plus some additional land adjacent to the RPZ. PTAA now owns a portion of the land within Zone 3 and may acquire additional land within Zone 3 in the future. At present, Zone 3 contains extensive commercial and light industrial development. The Watershed Map shows the boundaries of Zone 3 based on the RPZ and runway location that is currently proposed by the PTAA. If the location of the RPZ changes in the final design of the runway, Zone 3, as referred to in this Plan, will coincide with the revised RPZ plus the adjacent land shown on the Map. There are three water bodies within the Airport portion of the Randleman Lake Watershed as shown on the U.S.G.S. Topographic Map ("Guilford, N.C." revised 1994) for the area: (1) a stream along the southeast boundary of Zone 1, (2) a pond on the northwest side of Zone 3 and (3) a stream, also within Zone 3, below the pond. These streams are ephemeral. PTAA's plan for meeting the requirements of this portion of the Randleman Lake Regulations is as follows: 1. PTAA's goal is to direct future development within its portion of the Randleman Lake Watershed primarily to Zone 2. 2. PTAA plans to demolish a portion of the existing development within Zone 2, in the vicinity of the proposed runway, as well as a portion of the existing development within Zone 3, including warehouses and adjacent parking areas August, 2001 Section 7-Page 2 Randleman Lake within those zones. As a result of this demolition, approximately 20 acres of existing Built Upon Area will actually be removed and will be replaced with natural ground cover. 3. The only new development that is currently planed by PTAA within Zone 1 is an upgrade of the instrument approach to Runway 5R. If PTAA decides in the future to undertake any other development within Zone 1, it will comply with FAA restrictions that apply to the Runway Protection Zone (RPZ) in the approach to the runway. (The limits of the RPZ are shown on the Watershed Map.) These restrictions prohibit residential development, places of public assemblage, and fuel storage facilities from being relocated within an RPZ. 4. Subject to the issuance by the FAA of a favorable Record of Decision and to the satisfaction of certain other conditions, PTAA presently plans to construct a proposed Runway 5R-23L and to establish the RPZ for the new runway. If the new runway is constructed, the only development currently planned by PTAA within its portion of Zone 3 is the installation of an instrument approach system for the new runway, other navigational aids, and a service road. If PTAA decides in the future to undertake any other development within Zone 3, PTAA will comply with the FAA restrictions on development within the new RPZ; and PTAA will also maintain on Object Free Area, 800 feet wide, running the entire length of the runway and extending 1000 feet beyond the runway end. Additional Object Free Areas will be required for each taxiway. Although there are no current plans for doing so, PTAA may in the future extend the new runway to the southwest, but in such case the Object Free Area and RPZ for the runway would also be extended in that direction. This plan applies only to land that is owned by the PTAA within Zones 1 - 3 and not to any land that is owned by other parties. If PTAA acquires additional land within Zones 1 -3 in the future, the additional land will become subject to this plan at the time of its acquisition. The foregoing plan will not only minimize Built Upon Area within the Watershed, but will actually reduce Built Upon Area, in and around Zone 3, by approximately 20 acres. By establishing a goal of concentrating new development primarily in Zone 2, the plan will also target high intensity land uses away form surface waters and sensitive areas because the only water bodies within PTAA's portion of the Watershed are located in Zones 1 and 3. In carrying out the foregoing plan, PTAA will cooperate with the PTRWA by attending the annual update meetings for which it receives notice or is otherwise aware among the PTRWA and the local government units having territory within the Randleman Lake Watershed. August, 2001 Section 7-Page 3 Randleman Lake Coordinated Planning Efforts Regulation: (b) Coordination between all affected jurisdictions to encourage their development in the existing urban areas. The planning effort shall include provisions for areas of contiguous open space to be protected through conservation easements or other long- term protection measures and provisions to direct infrastructure growth towards existing urban development corridors rather than to rural lands. Goal: To achieve greater watershed protection and efficiency through regional coordination among the jurisdictions in the Randleman Lake Watershed. Action Items: PTAA's goal of locating new development primarily in Zone 2, will help to concentrate development in the areas in which it already exists and to divert development away from the open space that is owned by PTAA within Zone 1 and away from the area that will be restored to natural growth in Zone 3. Long-term protection measures will be imposed for all of these areas by PTAA's maintenance of the RPZ for the Runway 5R approach, by PTAA's establishment of an RPZ for the Runway 5L approach, and by the creation of the Object Free Areas for the new runway and taxiways, as described above. These protections will remain in effect for as long as the runways are operational. These restrictions will help to protect the open areas within Zones 1 and 3 and improve storm water quality within these Zones. PTAA will cooperate with the other jurisdictions within the Randleman Lake Watershed by attending the annual update meetings sponsored by the PTRWA, as stated above. PTAA will also assist the efforts of adjoining jurisdictions to develop land use plans that are compatible with airport development for areas outside the Airport boundaries, including plans for the maintenance of open space, where appropriate. August, 2001 Section 7-Page 4 Randleman Lake Evaluation of Existing Ordinances Regulation: (c) Evaluation of existing ordinances, municipal programs (maintenance, street cleaning, etc.) and other local policies to identify opportunities for storm water quality improvements including reducing the amount of built-upon area that is required for uses such as parking, building set-backs, road widths and cul-de-sacs. The evaluations shall consider development options such as multiple story buildings, mixed use to encourage pedestrian travel and mass transit and an identification of municipal activities and procedures that may be modified to allow for storm water pollution prevention opportunities. Goal: To identify opportunities to fine tune existing ordinances and policies so as to achieve better quality in the Randleman Lake Watershed. Action Items: PTAA is restricted in its ability to alter land use requirements by FAA development standards, such as height and setback requirements, and by PTAA's obligation to conform to Airport Layout Plan that is approved for the Airport by the FAA. However, PTAA will attempt to achieve storm water quality improvements as follows: 1. In undertaking new development projects within the Randleman Lake Watershed, PTAA will investigate design alternatives that reduce new Built Upon Area. 2. In grading areas within the Randleman Lake Watershed, PTAA will attempt to control soil erosion and sedimentation by phasing grading operations, and by accelerating the establishment new ground cover over graded areas, so as to reduce the time that unprotected areas are exposed to erosion. 3. All new development projects that are undertaken by PTAA throughout the Airport, including Zones 1 - 3, will comply with the watershed protection requirements set forth in PTAA's Watershed Ordinance and this SWMP unless a valid Variance is granted under the procedures set forth in the Ordinance. Pursuant to the Watershed Ordinance, PTAA has elected to apply high density criteria to all new development projects resulting in a new Built Upon Area of more than five acres. This requirement is in excess of the state minimum requirements because the Built Upon Percentage at the Airport is less than 241/0, and therefore PTAA could have elected to apply low-density August, 2001 Section 7-Page 5 Randleman Lake criteria to all new development at the Airport. As a result of the election made by PTAA, engineered storm water controls will be required for all projects in excess of the five-acre limit. The Watershed Ordinance also requires that new development projects resulting in new Built Upon Area of five acres or less be designed, to the maximum extent practicable, to minimize Built Upon Area, to direct storm water runoff away from surface waters, and to incorporate Best Management Practices to minimize water quality impacts. A Watershed Protection Plan will be required for all new development projects (regardless of size) showing how the applicable criteria will be met. These requirements will greatly reduce the impact of any new development that does occur within the Randleman Lake Watershed. 4. PTAA will implement a Spill Prevention Control and Countermeasure Plan (SPCCP) that will establish procedures to help prevent, control and remediate spills of oil or hazardous materials at the Airport. Public Education Programs Regulation: (e) Implementation of watershed protection public education programs. Goal: To educate the community about impacts of storm water discharge on water bodies and what is needed to reduce storm water pollution in the Randleman Lake Watershed. Action Items: There is no population living within the portion of the Airport that leis within the Randleman Lake Watershed. However, PTAA will undertake, through distribution of this SWMP and PTAA's SPCCP, to educate Airport tenants concerning the impacts of storm water discharge and the actions that are necessary to improve storm water quality at the Airport. PTAA will also make a presentation to Airport tenants, upon the final adoption of this SWMP, of the requirements of the plan and of the SPCCP, and of the impact of storm water discharge on water quality. PTAA will also explore the possibility of participating in a multi jurisdictional interlocal agreement to meet the educational requirements of the Randleman Rules. The proposed interlocal agreement would allow the communities to cooperate in the creation and dissemination of educational material that would educate the community about the effects of storm water pollution on our limited water resources. August, 2001 Section 7-Page 6 Randleman Lake Identification and Removal of Illegal Discharges Regulation: (e) Identification and removal of illegal discharges. Goal: To improve water quality through the identification and removal of illegal discharges within the Randleman Lake Watershed. Action Items: Through the implementation of its SPCCP, PTAA will attempt to locate areas at the Airport form which an illegal discharge might occur and to identify the storm water outlet that would be affected. PTAA also anticipates the issuance of an NPDES permit to PTAA, in which Airport tenants will be named a co-permittees, with respect to storm water discharge at the Airport. The permit is expected to require periodic monitoring of storm water outfalls at the Airport for various substances, including oil and hazardous material. If an illegal discharge is identified by PTAA on PTAA property within the Randleman Lake Watershed, PTAA will attempt to determine the source. If PTAA's own activities are the source of the discharge, the discharge will be discontinued. If the discharge results from a source other than PTAA, such as a PTAA tenant, PTAA shall take such reasonable actions as it shall determine, within its authority, to assist in the removal of the discharge. PTAA will also include in all new lease agreements that it enters into with its tenants a requirement that, upon discovery by the tenant or the receipt of notification, the tenant will take such remedial actions as may be legally required with respect to any illegal use or release of hazardous materials by the tenant on PTAA property. Identification of Potential Storm Water Retrofit Locations Regulation: (f) Identification of suitable locations for potential storm water retrofits (such as riparian areas) that could be funded by various sources. Goal: To develop a process to identify and plan for storm water retrofits in the Randleman Lake Watershed. August, 2001 Section 7-Page 7 Randleman Lake y Action Items: The removal of existing Built Upon Area from Zone 3 and surrounding land, as described above, will result in the restoration of natural ground cover, including grass and low shrub-type vegetation. (Tall growing trees will not be permitted within the RPZ in the approach to Runway 5L). In grading the previously developed land, PTAA will develop a series of meandering grass swales. A grass Swale is noted by the NCDENR in its publication of Best Management Practices as potentially removing up to 35% of Total Suspended Solids (TSS). PTAA will also consider planing grass filter strips below any remaining impervious surface to filter runoff from these areas. Filter strips are noted by the NCDENR as potentially removing up to 40% of TSS. August, 2001 Section 7-Page 8 Randleman Lake ?ooz isr*nv '5u t3311s 6 A& L•J C m 3: Ma 0 Z -I m I m a C ONVI 3NOZ 3NOZ N01133108d AVMNnd ------- AdVONn09 03HS831VM -? A183dOdd 1dOddIV ON393.1 15 Avm(Nna a3SOd0Sd - £ 3NOZ J A? 'S3MIVd 113HIO AS a3NMO SI JVHl aNVI ANd Ot ION aNd £-l S3NOZ NIHIIM VVld AS 03NMO SI IVH1 aNVI 01 A1NO S311ddd NVId SIH1 i oDJ v - Oi -3NOZ b QQ? I 1 nNe aoxieP _ AT717 s 0 PP w S DEEP HSHUVM NIC 04 HJIH HMH 3a GIVEN Iii b L T .,r: r??S of 1 b -. N 1;51 ?' - ?3A1? Jl 'w:Il'NLn9? ' ? ys ,' M i W 1 ? r - ?' •• ••. io RA.*" 00 son L NOZ ???• toy ? • ? • NSE?"`E • II1f ? ® • • • CERTIFICATE OF ADOPTION I certify that I am the Secretary of the Piedmont Triad Airport Authority and that at a meeting duly called and held on August 21, 2001, the attached resolution and accompanying "Storm Water Plan for Deep River (Randleman Lake) Watershed" were duly adopted by said Authority. This the I( day of August, 2001. -Secretary,`' Piedmont Triad Airpor Authority k Resolution Adopting Randleman Lake Storm Water Management Plan WHEREAS, under 15A NCAC 213; 0251 of the North Carolina Code of Regulations, local governments having land in the Randleman Lake Watershed, including the Authority, must adopt a comprehensive storm water management plan, that is approved by the North Carolina Environmental Management Commission, for the portion of their jurisdiction that is within the watershed boundary and; WHEREAS, the staff of the Authority has developed a proposed plan in accordance with the state regulations entitled A Storm Water Plan for the Deep River (Randleman Lake) Watersheds @ (the AProposed Plan@), a copy of which has been furnished to each of the members of the Authority, and such plan has been approved on behalf of the North Carolina Environmental Management Commission by its Water Quality Committee; and WHEREAS, the adoption and implementation of the Proposed Plan would fulfill the Authority's obligations under the applicable regulations, would promote good watershed management of the portion of the Randleman Lake Watershed that is within the Authority's jurisdiction, and would help to improve water quality within the Randleman Lake Watershed and the Randleman Lake Reservoir now under construction; NOW, THEREFORE, BE IT RESOLVED by the Piedmont Triad Airport Authority that the Proposed Plan is hereby approved and adopted as the Randleman Lake Storm Water Management Plan of the Authority in accordance with 15A NCAC 2B. 0251 and that the officers and staff of the Authority are hereby directed to Implement such plan in accordance with its terms. August, 2001 Section 7 Resolution Randleman Lake 7.0 Storm Water Plan for Deep River (Randleman Lake) Watershed Under 15A NCAC 2B. 0251 (4), local governments with land use authority within the proposed Randleman Lake Watershed are required to adopt comprehensive storm water management plans for the portion of the watershed that is under their jurisdiction. The Deep River, High Point Watershed, as described in this SWMP, and as shown on the Watershed Map that appears at the end of this Section, is a part of the larger Randleman Lake Watershed, and PTAA is therefore required by 15A NCAC 2B.0251(4) to adopt a comprehensive storm water plan for the portion of the Airport that is within this area. This Section 7 sets forth the plan the PTAA has adopted. It is intended as a supplement to the rest of this SWMP, and applies only to land within the Deep River, High Point Watershed that PTAA presently owns or acquires in the future. The regulations describe six separate components to be included in the plan. The applicable requirements of the regulations, and the corresponding provisions of PTAA's plan, are as follows: Evaluation of Existing Land Use Regulation: (a) Evaluation of existing land use within Oak Hollow Lake subwatershed, High Point Lake subwatershed and Deep Riverl subwatershed in the Randleman Lake Watershed with recommendations that show how overall built-upon area (for existing and future development) for each subwatershed can be minimized and high intensity land uses can be targeted away from surface waters and sensitive areas. Oak Hollow Lake subwatershed is defined as all land areas draining to Oak Hollow Lake. High Point Lake subwatershed is defined as all land areas draining to High Point Lake, East Fork Deep River and West Fork Deep River from Oak Hollow Lake Dam. Deep River 1 subwatershed is defined as all land areas draining to the Deep River from High Point Lake Dam to Freeman Mill Dam. This evaluation shall be done by the local governments having jurisdiction in those watersheds, working in cooperation with the PTRWA. Goal: Evaluate and possibly modify existing land use plans and development patterns to achieve better protection of the Randleman Lake Watershed. August, 2001 Section 7-Page 1 Randleman Lake Action Items: The Watershed Map appearing at the end of this Section identifies three separate zones within the Deep River, (Randleman Lake) Watershed, for planning purposes, as follows: ¦ Zone 1: Zone 1 consists of the Runway Protection Zone (RPZ) in the approach to existing Runway 5R, as shown on the map, plus some adjoining land outside of the RPZ. PTAA owns most of the land within Zone 1 as shown on the map. The land that is owned by PTAA within Zone 1 is presently undeveloped, except for an instrument landing system, other navigational aids, and a gravel service road. ¦ Zone 2: Zone 2 consists of all of the land that is owned by PTAA within the Randleman Lake Watershed that is not within Zone 1 or Zone 3. Zone 2 includes major airport facilities, including a portion of Runway 14-32 and associated taxiways, an air cargo building and major aircraft hangars. PTAA is presently relocating its Maintenance Building within Zone 2. ¦ Zone 3: Zone 3 is located at the southwest end of proposed Runway 5L-23R. It will consist of the portion of the RPZ for the proposed runway north of the right- of-way of U.S. 421 and east of the right-of-way for U.S. 68, plus some additional land adjacent to the RPZ. PTAA now owns a portion of the land within Zone 3 and may acquire additional land within Zone 3 in the future. At present, Zone 3 contains extensive commercial and light industrial development. The Watershed Map shows the boundaries of Zone 3 based on the RPZ and runway location that is currently proposed by the PTAA. If the location of the RPZ changes in the final design of the runway, Zone 3, as referred to in this Plan, will coincide with the revised RPZ plus the adjacent land shown on the Map. There are three water bodies within the Airport portion of the Randleman Lake Watershed as shown on the U.S.G.S. Topographic Map ("Guilford, N.C." revised 1994) for the area: (1) a stream along the southeast boundary of Zone 1, (2) a pond on the northwest side of Zone 3 and (3) a stream, also within Zone 3, below the pond. These streams are ephemeral. PTAA's plan for meeting the requirements of this portion of the Randleman Lake Regulations is as follows: 1. PTAA's goal is to direct future development within its portion of the Randleman Lake Watershed primarily to Zone 2. 2. PTAA plans to demolish a portion of the existing development within Zone 2, in the vicinity of the proposed runway, as well as a portion of the existing development within Zone 3, including warehouses and adjacent parking areas August, 2001 Section 7-Page 2 Randleman Lake within those zones. As a result of this demolition, approximately 20 acres of existing Built Upon Area will actually be removed and will be replaced with natural ground cover. 3. The only new development that is currently planed by PTAA within Zone 1 is an upgrade of the instrument approach to Runway 5R. If PTAA decides in the future to undertake any other development within Zone 1, it will comply with FAA restrictions that apply to the Runway Protection Zone (RPZ) in the approach to the runway. (The limits of the RPZ are shown on the Watershed Map.) These restrictions prohibit residential development, places of public assemblage, and fuel storage facilities from being relocated within an RPZ. 4. Subject to the issuance by the FAA of a favorable Record of Decision and to the satisfaction of certain other conditions, PTAA presently plans to construct a proposed Runway 5R-23L and to establish the RPZ for the new runway. If the new runway is constructed, the only development currently planned by PTAA within its portion of Zone 3 is the installation of an instrument approach system for the new runway, other navigational aids, and a service road. If PTAA decides in the future to undertake any other development within Zone 3, PTAA will comply with the FAA restrictions on development within the new RPZ; and PTAA will also maintain on Object Free Area, 800 feet wide, running the entire length of the runway and extending 1000 feet beyond the runway end. Additional Object Free Areas will be required for each taxiway. Although there are no current plans for doing so, PTAA may in the future extend the new runway to the southwest, but in such case the Object Free Area and RPZ for the runway would also be extended in that direction. This plan applies only to land that is owned by the PTAA within Zones 1 - 3 and not to any land that is owned by other parties. If PTAA acquires additional land within Zones 1 -3 in the future, the additional land will become subject to this plan at the time of its acquisition. The foregoing plan will not only minimize Built Upon Area within the Watershed, but will actually reduce Built Upon Area, in and around Zone 3, by approximately 20 acres. By establishing a goal of concentrating new development primarily in Zone 2, the plan will also target high intensity land uses away form surface waters and sensitive areas because the only water bodies within PTAA's portion of the Watershed are located in Zones 1 and 3. In carrying out the foregoing plan, PTAA will cooperate with the PTRWA by attending the annual update meetings for which it receives notice or is otherwise aware among the PTRWA and the local government units having territory within the Randleman Lake Watershed. August, 2001 Section 7-Page 3 Randleman Lake Coordinated Planning Efforts Regulation: (b) Coordination between all affected jurisdictions to encourage their development in the existing urban areas. The planning effort shall include provisions for areas of contiguous open space to be protected through conservation easements or other long- term protection measures and provisions to direct infrastructure growth towards existing urban development corridors rather than to rural lands. Goal: To achieve greater watershed protection and efficiency through regional coordination among the jurisdictions in the Randleman Lake Watershed. Action Items: PTAA's goal of locating new development primarily in Zone 2, will help to concentrate development in the areas in which it already exists and to divert development away from the open space that is owned by PTAA within Zone 1 and away from the area that will be restored to natural growth in Zone 3. Long-term protection measures will be imposed for all of these areas by PTAA's maintenance of the RPZ for the Runway 5R approach, by PTAA's establishment of an RPZ for the Runway 5L approach, and by the creation of the Object Free Areas for the new runway and taxiways, as described above. These protections will remain in effect for as long as the runways are operational. These restrictions will help to protect the open areas within Zones 1 and 3 and improve storm water quality within these Zones. PTAA will cooperate with the other jurisdictions within the Randleman Lake Watershed by attending the annual update meetings sponsored by the PTRWA, as stated above. PTAA will also assist the efforts of adjoining jurisdictions to develop land use plans that are compatible with airport development for areas outside the Airport boundaries, including plans for the maintenance of open space, where appropriate. August, 2001 Section 7-Page 4 Randleman Lake Evaluation of Existing Ordinances Regulation: (c) Evaluation of existing ordinances, municipal programs (maintenance, street cleaning, etc.) and other local policies to identify opportunities for storm water quality improvements including reducing the amount of built-upon area that is required for uses such as parking, building set-backs, road widths and cul-de-sacs. The evaluations shall consider development options such as multiple story buildings, mixed use to encourage pedestrian travel and mass transit and an identification of municipal activities and procedures that may be modified to allow for storm water pollution prevention opportunities. Goal: To identify opportunities to fine tune existing ordinances and policies so as to achieve better quality in the Randleman Lake Watershed. Action Items: PTAA is restricted in its ability to alter land use requirements by FAA development standards, such as height and setback requirements, and by PTAA's obligation to conform to Airport Layout Plan that is approved for the Airport by the FAA. However, PTAA will attempt to achieve storm water quality improvements as follows: 1. In undertaking new development projects within the Randleman Lake Watershed, PTAA will investigate design alternatives that reduce new Built Upon Area. 2. In grading areas within the Randleman Lake Watershed, PTAA will attempt to control soil erosion and sedimentation by phasing grading operations, and by accelerating the establishment new ground cover over graded areas, so as to reduce the time that unprotected areas are exposed to erosion. 3. All new development projects that are undertaken by PTAA throughout the Airport, including Zones 1 - 3, will comply with the watershed protection requirements set forth in PTAA's Watershed Ordinance and this SWMP unless a valid Variance is granted under the procedures set forth in the Ordinance. Pursuant to the Watershed Ordinance, PTAA has elected to apply high density criteria to all new development projects resulting in a new Built Upon Area of more than five acres. This requirement is in excess of the state minimum requirements because the Built Upon Percentage at the Airport is less than 24%, and therefore PTAA could have elected to apply low-density August, 2001 Section 7-Page 5 Randleman Lake criteria to all new development at the Airport. As a result of the election made by PTAA, engineered storm water controls will be required for all projects in excess of the five-acre limit. The Watershed Ordinance also requires that new development projects resulting in new Built Upon Area of five acres or less be designed, to the maximum extent practicable, to minimize Built Upon Area, to direct storm water runoff away from surface waters, and to incorporate Best Management Practices to minimize water quality impacts. A Watershed Protection Plan will be required for all new development projects (regardless of size) showing how the applicable criteria will be met. These requirements will greatly reduce the impact of any new development that does occur within the Randleman Lake Watershed. 4. PTAA will implement a Spill Prevention Control and Countermeasure Plan (SPCCP) that will establish procedures to help prevent, control and remediate spills of oil or hazardous materials at the Airport. Public Education Programs Regulation: (e) Implementation of watershed protection public education programs. Goal: To educate the community about impacts of storm water discharge on water bodies and what is needed to reduce storm water pollution in the Randleman Lake Watershed. Action Items: There is no population living within the portion of the Airport that leis within the Randleman Lake Watershed. However, PTAA will undertake, through distribution of this SWMP and PTAA's SPCCP, to educate Airport tenants concerning the impacts of storm water discharge and the actions that are necessary to improve storm water quality at the Airport. PTAA will also make a presentation to Airport tenants, upon the final adoption of this SWMP, of the requirements of the plan and of the SPCCP, and of the impact of storm water discharge on water quality. PTAA will also explore the possibility of participating in a multi jurisdictional interlocal agreement to meet the educational requirements of the Randleman Rules. The proposed interlocal agreement would allow the communities to cooperate in the creation and dissemination of educational material that would educate the community about the effects of storm water pollution on our limited water resources. August, 2001 Section 7-Page 6 Randleman Lake Identification and Removal of Illegal Discharges Regulation: (e) Identification and removal of illegal discharges. Goal: To improve water quality through the identification and removal of illegal discharges within the Randleman Lake Watershed. Action Items: Through the implementation of its SPCCP, PTAA will attempt to locate areas at the Airport form which an illegal discharge might occur and to identify the storm water outlet that would be affected. PTAA also anticipates the issuance of an NPDES permit to PTAA, in which Airport tenants will be named a co-permittees, with respect to storm water discharge at the Airport. The permit is expected to require periodic monitoring of storm water outfalls at the Airport for various substances, including oil and hazardous material. If an illegal discharge is identified by PTAA on PTAA property within the Randleman Lake Watershed, PTAA will attempt to determine the source. If PTAA's own activities are the source of the discharge, the discharge will be discontinued. If the discharge results from a source other than PTAA, such as a PTAA tenant, PTAA shall take such reasonable actions as it shall determine, within its authority, to assist in the removal of the discharge. PTAA will also include in all new lease agreements that it enters into with its tenants a requirement that, upon discovery by the tenant or the receipt of notification, the tenant will take such remedial actions as may be legally required with respect to any illegal use or release of hazardous materials by the tenant on PTAA property. Identification of Potential Storm Water Retrofit Locations Regulation: (f) Identification of suitable locations for potential storm water retrofits (such as riparian areas) that could be funded by various sources. Goal: To develop a process to identify and plan for storm water retrofits in the Randleman Lake Watershed. August, 2001 Section 7-Page 7 Randleman Lake Action Items: The removal of existing Built Upon Area from Zone 3 and surrounding land, as described above, will result in the restoration of natural ground cover, including grass and low shrub-type vegetation. (Tall growing trees will not be permitted within the RPZ in the approach to Runway 5L). In grading the previously developed land, PTAA will develop a series of meandering grass swales. A grass swale is noted by the NCDENR in its publication of Best Management Practices as potentially removing up to 35% of Total Suspended Solids (TSS). PTAA will also consider planing grass filter strips below any remaining impervious surface to filter runoff from these areas. Filter strips are noted by the NCDENR as potentially removing up to 40% of TSS. August, 2001 Section 7-Page 8 Randleman Lake i v m m m m I G1 0 Z C D m m m v t ONVI 3NOZ m 3NOZ N011o3108d AVMNn8 _______ AdVONnoe 03HS831VM A183dOdd 180d8IV ON3O31 1S AdM(na a3SOd0Hd £ 3NOZ mi 'S311Wd b3H10 AS a3NMO SI LVHI aNdl ANd Ol ION aNV C-l S3NOZ NIH11M bald AS a3NMO SI IVHl aNVI 01 A1NO S311ddV NVId SIH1 b s_ _ LJ ' f r s 0 66 . E -Z-ANGZ ,3 oe KGNVAT S E o m 9o N OJ,?. Sp?' i HSHUMM 1N1 04 H91H i-- a3Alb 3a DEEP RIVEN T h?-_.. ?.r TT W ?s ?r -W 4W a it's ? o W 00 •. .• ? a??w?Y ? s •? `?`? ? • ? L NOZ' ion ? • ' ? , NIEaStvtE ? • • • 1T • s LAWGIBB JOB NO?70 'O ' !?ZS-? SHEET _L OF G R C7 -Lj P PHASE JOB NAME ???' ' TASK Q "?? (u?GGC LAW Engineering & Environmental Services, Inc. 3301 Atlantic Avenue BY DATE / B Raleigh, NC 27604 ................... ............ ............. ........... ............. ............ ............. , ............ ............ ........... . .............................................................. ............. ............ ......... CHECKED BY ............................ ,..................................... ........................ ........... DATE .... ...... ........................... ............ ............ .......................... ...................................... ........................... , , 73. AS" V7A/Knfl- ZO&I 1"37. , , S7 !'117/ / f'G?9ov' . P T ,? s } .... .:....... ...... .... ... f l ...................... ... .:. ...... .. '. .t....:...... t :?`VV ... ... I ... ........ 1 /' F2,6'?/Y-? E _ ? I J ( l JCS/ .. [ J,.. 11 ......pp,?. E ?? t`..YL . ._ ........ f `A ._.....( It i. E .// .... ....r ?? s?V DQ t 44 I .: ..... ... .... I .. .. 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Piedmont Triad International Airport November 01, 2001 LAW Project 30740-0-4253 Wetland and Stream Mitigation Plan Table 3b Proposed USACE Wetland and Stream Mitigation Summary WETLAND PRESERVATION CREATION RESTORATION TOTAL CREDIT MITIGATION acres ratio credit acres ratio credit acres ratio credit Acres (23.8 needed) Horsepen Creek 0.0 10.0 0.0 11.0 6.0 1.8 6.0 2.0 3.0 17.0 18% 4.8 20% 0 0.0 10.0 0.0 0.0 6.0 0.0 0.0 2.0 0.0 0.0 0% 0.0 0% Brush Creek 52.3 5.0 10.5 5.3 6.0 0.9 7.1 2.0 3.6 64.7 69% 14.9 61% 0 5.0 5.0 1.0 0.0 6.0 0.0 0.0 2.0 0.0 5.0 5% 1.0 4% North Park 0.0 10.0 0.0 0.0 6.0 0.0 0.0 2.0 0.0 0.0 0% 0.0 0% Robinson Park 0.0 10.0 0.0 0.0 6.0 0.0 0.0 2.0 0.0 0.0 0% 0.0 0% WillowBrook Par] 0.0 10.0 0.0 0.0 6.0 0.0 0.0 2.0 0.0 0.0 0% 0.0 0% 0 0.0 10.0 0.0 0.0 6.0 0.0 0.0 2.0 0.0 0.0 0% 0.0 0% Benaja Swamp 0.0 10.0 0.0 0.0 6.0 0.0 0.0 2.0 0.0 0.0 0% 0.0 0% 0 0.0 10.0 0.0 0.0 6.0 0.0 0.0 2.0 0.0 0.0 0% 0.0 0% Couch Property 0.0 10.0 0.0 0.0 6.0 0.0 0.0 2.0 0.0 0.0 0% 0.0 0% 0 0.0 10.0 0.0 0.0 6.0 0.0 0.0 2.0 0.0 0.0 0% 0.0 0% Causey Farms 0.0 10.0 0.0 0.0 6.0 0.0 7.0 2.0 3.5 7.0 7% 3.5 14% SUBTOTAL: 57.3 9.2 11.5 16.3 6.0 2.7 20.1 2.0 10.1 93.7 24.2 61% 47% 17% 11% 21% 41% 3.9 0.5 STREAM PRESERVATION ENH ANCEMENT RESTORATION TOTAL CREDIT MITIGATION l.f. ratio credit 1.f ratio credit l.f. ratio credit Linear Feet (13917 needed) Horsepen Creek 0 10.0 0 0 4.0 0 4,960 1.0 4,960 4,960 24% 4,960 36% 0 0 10.0 0 0 4.0 0 0 1.0 0 0 0% 0 0% Brush Creek 3,690 5.0 738 0 4.0 0 100 1.0 100 3,790 18% 838 6% 0 2,000 5.0 400 0 4.0 0 0 1.0 0 2,000 10% 400 3% North Park 0 10.0 0 0 4.0 0 650 1.0 650 650 3% 650 5% Robinson Park 0 10.0 0 0 4.0 0 950 1.0 950 950 5% 950 7% WillowBrook Parl 0 10.0 0 0 4.0 0 910 1.0 910 910 4% 910 7% 0 0 10.0 0 0 4.0 0 0 1.0 0 0 0% 0 0% Benaja Swamp 0 10.0 0 0 4.0 0 0 1.0 0 0 0% 0 0% 0 0 10.0 0 0 4.0 0 0 1.0 0 0 0% 0 0% Couch Property 0 10.0 0 800 5.0 160 0 1.0 0 800 4% 160 1% 0 0 10.0 0 0 4.0 0 0 1.0 0 0 0% 0 0% Causey Farms 0 10.0 0 2,250 4.0 563 4,500 1.0 4,500 6,750 32% 5,063 36% SUBTOTAL: 5,690 9.2 1,138 3,050 4.1 723 12,070 1.0 12,070 20,810 13,931 27% 8% 15% 5% 58% 87% 1.5 14 Prepared / Date: 1 of 1 Checked / Date: AMACTEC ' November 3, 2003 Ms. Jean B. Manuele, Chief ' Raleigh Regulatory Field Office U.S. Department of the Army Wilmington District Corps of Engineers Regulatory Division ' P.O. Box 1890 Wilmington, NC 28402-1890 WETLANDS/ 401 GROUP NO V 0 4 2003 WATER QUALITY SECTION Mr. John R. Dorney, Chief 401 Wetlands 'Certification Unit N.C. Dept. Environment and Natural Resources Division of Water Quality 1650 Mail Service Center Raleigh, NC 27699-1650 ' Attention: Mr. John Thomas . Ms. Cyndi Karoly Subject: Proposed Revision to Off-Site Component of Mitigation Plan for ' Piedmont Triad International Airport Section 404 Action ID No. 200021655 Section 401 Water Quality Certification No. 3428 ' Dear Ms. Manuele and Mr. Dorney: ' Pursuant to discussions of October 30, 2003, on behalf of the Piedmont Triad Airport Authority (PTAA, applicant) we are hereby requesting your concurrence that the three off-site stream restoration components located in Burlington (2,510 linear feet total), of the Wetland and Stream ' Mitigation Plan for the referenced project, be replaced by an equal linear footage of additional stream restoration at the Causey Farm site (to total 5,910 linear feet, if approved). It is anticipated that the contiguous Causey Farm stream restoration project will provide better success potential and more appropriate functional replacement for stream impacts than the relatively ' short, separate Burlington stream segments constrained by utilities, landfill, park/municipal ordinances, adjacent landowners, and public use. We respectfully request that the attached Conceptual Mitigation Report replace the Burlington and previously submitted Causey Farm t components of the Wetland and Stream Mitigation Plan for this project. Please do not hesitate to contact me regarding the proposed revisions to the off-site mitigation component. Sincerely, MACTEC ENGINEERING AND CONSULTING, INC. ' Richard B. Darling, C.E Principal Environmen Scientist ' Enclosures: Conceptual Mitigation Report for Causey Farm Mitigation Site cc: Mickie L. Elmore, PTAA. Kevin J. Baker, Baker & Associates. ' RBD/KJB/MLE:rbd P:\30740\2000 Projects\4253 PTTA\MOdification\Request Modification Ldoc ' MACTEC Engineering and Consulting 3301 Atlantic Avenue • Raleigh, NC 27604 ' 919-876-0416 • Fax: 919-831-8136 WETLANDS Preservation Creation Restoration Total Horse en Creek 12.6 acres 2.0 acres 14.6 acres Brush Creek 69.9 acres 5.3 acres 7.4 acres 82.6 acres Cause Farms 4.0 acres 4.0 acres Subtotal: 69.9 acres 17.9 acres 13.4 acres 101.2 acres STREAMS Preservation Restoration Total Horse en Creek 6,107 linear feet 6,107 linear feet Brush Creek 14,510 linear feet 200 14,710 linear feet Cause Farms 5,910 linear feet 5,910 linear feet Subtotal: 14,510 linear feet 12,217 linear feet 26,727 linear feet O CONCEPTUAL MITIGATION REPORT CAUSEY FARM MITIGATION SITE GUILFORD COUNTY, NORTH CAROLINA Prepared for: d'+ d Restoration Systems 1101 Haynes Street, Suite 203 Raleigh, North Carolina 27604 Prepared by: 1 EcoScience EcoScience Corporation 1101 Haynes Street, Suite 101 Raleigh, North Carolina 27604 February 2002 i 1 1 1 1 1 TABLE OF CONTENTS Page LIST OF APPENDICES, FIGURES, AND TABLES ............................ ii 1.0 INTRODUCTION ............................................ 1 2.0 RELEVANT FEATURES ........................................ 5 2.1 Physiography, Topography, and Land Use ...................... 5 2.2 Vegetation ........................................... 8 2.3 Stream Characterization .................................. 8 2.3.1 Stream Classification ............................... 10 2.3.2 Dimension ...................................... 10 2.3.3 Profile ......................................... 12 2.3.4 Plan Form ....................................... 12 2.4 Wetlands ............................................ 13 3.0 CONCEPTUAL MITIGATION PLAN ................................ 15 3.1 Stream Restoration ..................................... 15 3.1.1 Channel Construction on New Location .................. 17 3.1.2 Bank Stabilization and Grade Control Structures ............. 17 3.1.3 Bankfull Bench Construction .......................... 18 3.1.4 Ford Removal and Construction ........................ 18 3.2 Wetland Restoration .................................... 19 3.3 Vegetative Planting ..................................... 19 4.0 MONITORING PLAN ......................................... 21 4.1 Stream Monitoring ...................................... 21 4.2 Stream Success Criteria ................................... 21 4.3 Wetland Monitoring ..................................... 21 4.4 Wetland Success Criteria ................................. 22 4.5 Vegetation Monitoring ................................... 22 4.6 Vegetation Success Criteria ............................... 23 4.7 Contingency .......................................... 23 5.0 DISPENSATION OF THE PROPERTY .............................. 24 6.0 REFERENCES ..............................................25 E r i i i LIST OF FIGURES Figure 1: Site Location ...................... .................... 2 Figure 2: Service Area ....................... ................... 3 Figure 3: Topography ....................... .................. . 6 Figure 4: Land Use ......................... ................... 7 Figure 5: Hydric Soils ....................... ................... 14 Figure 6: Conceptual Mitigation Plan ............. ................... 16 LIST OF TABLES Table 1: Stream Geometry Attributes ............................... 9 APPENDICES Appendix A: Stream Gauge Data Appendix B: On-Site Cross Section Data t CONCEPTUAL MITIGATION REPORT CAUSEY FARM MITIGATION SITE GUILFORD COUNTY, NORTH CAROLINA 1 1.0 INTRODUCTION Restoration Systems is currently evaluating stream and wetland restoration potential at a site located in southeastern Guilford County, approximately 5 miles north of the Town of Liberty (Figure 1). The Causey Farm Mitigation Site encompasses approximately 288 acres of land which is currently utilized for livestock grazing and hay production. Streams and wetlands within the property have been cleared of native forest vegetation and are accessible to livestock, resulting in local disturbance to stream banks and wetland soil surfaces. The Site is located in U.S. Geological Service (USGS) Hydrological unit #03030002 of the Cape Fear River Basin (Figure 2). This portion of the Cape Fear River Basin encompasses portions of Guilford, Rockingham, Caswell, Alamance, Orange, Chatham, and Durham Counties. Towns potentially serviced by this mitigation project include Greensboro, Burlington, Reidsville, and Chapel Hill. The Site is intended to be developed to provide stream and riverine wetland mitigation credit to various projects in the region. The purpose of this study is to determine potential restoration alternatives on the Causey Farm Mitigation Site (hereafter referred to as the "Site"). This study is designed to address the following objectives: 1) Provide plan views of the Site including land use constraints, topographic features, wetlands, existing vegetation, or other features that may effect the restoration project. 2) Classify on-site streams according to fluvial geomorphic attributes measured within each reach. 3) Develop a preliminary, conceptual plan of potential stream and wetland mitigation activities. 4) Determine a monitoring strategy including mitigation success criteria. 5) ..Assess potential managers for the Site once mitigation activities are complete. This document is intended to provide information to agency personnel for discussion of project parameters, including Site suitability and mitigation options / activities. Potential restoration alternatives have been presented based primarily upon professional judgement. 1 RISC CA I +?.I fulEDFn a.J? J. t I `; iw° i FH': '.'rbL r I LVPJI ?-? A' 'mil Q0.^ ?.-_ X' ML - r Nd ea l` . R • a t fI .\ 1 r ` '' e fi _ , rE:n y }s arrET' 100 t - ,v rau gip,.,. ? j ?.`! ?,.;?tr? a q ? ? _ - ?. ._ _` rm •. ( 1, u I` . ? r' ro - ' • ?? ` t?. P Ji T YID i _4 \? /?S/ ?i tf L. JI -' QIQ- J' I ?4 b,* , ?4 \ dCP ,: / mram -x r st r:\? o.. • tx C\ _ -! _ I, s' /' \ - <9 ?.?. ?, ,c'?r?:a,tha . '...? ? ?` I?>~ >"-? ? •" ? ? y, fpNS ! l c ? ? [ lA C Cr drldtC lM- 7OT .. 1 r \ F r. ? ° ?G+ _ B / ? - =- ?` - _.. .. r L_. .bYroNr. •.SKmu al. ? \ t 1-n? a sc lw % tv s ..Y "=?? ? ? `°t ` • - ?'. fi d.ev.. P ? _ ;p`t Jy ? 8 0„4.1 •? 7 "??`'•??l . . _ ?: ?: - ? ? 6%'Y?0.V , •wTay ' Fir h'P I -: :?:.? G?C< M,,? ll r t f % k ? ti Nainance . /? ? 1 . 3Teata, . W j MA. 10 'A R I - ?. 'Fr '? ?'.? q0 /. r .486d[GYgrOUry" ( +?9 d -.. 7 _ .q'H M r c, •r<? •.? `.mss -- --'-?-t- ?F a'--'Y - - 7-= r-3----rr '= , - 1 - + - i - r ' Y ?f. ,?•y q ?p- . ... r y+ aWxr - - ? _; ?? ? ``'?i- l ?? , ??vA ""y , ? /` ?! ( T ? ? ? ? 4 ?. I 6Z k/-? Cyr se. ? \\,? j ? ?' - 7. `'•.y ? ?.`?' -'• r t?? ` I <T CAUSEY FARM ,: -..' \.tdtawt'A Aa--4 ` ` MITIGATION, 'Y•J y ; . , founta r A -= tP, ib-- ? SITE .; r ??; ea I r : l _-_.,r '.. -,.`? `??n zw?? r ' coeu / I I !, ? ,,i ?? ? • fL ,. j \\4? .axk ? e'. `:. „li I I s t C-L ? ? ? I J ? ?f ? Z I ? ^ ? ?? ??? ? ? ra o 1 ecac lT 1 t •- ? t (l 1 27 / v ' ? r II ? 2 .? d.' $ ,mot __ ,? i??..., - c^ j." 4... I •ro _._. _-_._ T _ _- _ ? 1 ? ? ?, CauuY ? ?r-r?-C?'- ,T sb? ? r oc+• \ o„ ?. ? ? I Q" ` • ` " J l $I 7: I' ` '?N _-- - ? / :y ?°.' ° i8 I R - \- IFA3VA1f; ljYl j?b?p?1 O c a - ' ? a • i cAFm + . w?F L J'Q'.. [ e a '@? _ - - 1? a'ne ?aa ,--'` :5'?i"•E r?. sy,'' - a ?', F'&',.Jd=+ ??ggg l`T?Srrcrf er + b Q !? W -" {? .. _ I t ?_ _ ? - ? p 5 I -m faw Gr r`.'? ` M V ? ? c .{ n, 1 w 1 0 a F'• ?I ?.. ; /Pr prt _ jj 4 0.4 _ F j.`/f. _ - t - U ? PP Luwo4rry I E \ - ' ?' -j -_ 1 ii? ??9EN,-r'?Llffi F ? '•1 ?!. - .III III?._??'x,.'e >L? ? I -__._. I 1i[:-. "*.. ? "? Aam?,tr,?r j? i? ++ 9: - ^ `.ALaMrV1Ct C,u _ - I I• J . ® ` `qty o _ I ? a ?'rP a..uAO Ac S }Y? ? ~vcQ I ' mi. 4 mi. ' a a c I P - e 1:158.400 '< I A Source: 1977 North Carolina Atlas and Gazetteer, p.38. j - -_ --- - --- -- 5 lo Fwrew _ yQ ll-- tom 'y - ?.: M/" x /7 .\ Q?n.. ? ?.tP ra if.L > ry RJ •1 ".v ' f :^. ???' ! 3I±.,.? ?lf? ??r EcoScience Co -pai- ion SITE LOCATION CAUSEY FARM MITIGATION SITE Dwn. by: MAF Ckdby: "Gc Date: FIGURE - Guilford County, North Carolina FEB 2002 Raleigh, North Carolina Project: 98-029 I I I 1 1 1 1 1 1 1 1 1 1 s+ Z ?f Q N n m Q O ?? w W N N ' I B - w u Q u LL .. Q ccb W ? ?Q w o m ? N L C 4 o (n .rl `, Q? f.7 Z 4 m m a ? V - a U F ? U w c m P 3 cc >2 cc C ?- T `t ?• .? -.wit 00 2 C3 om--N .. m o ?' 3 c E Z 'r a /- -a C Y O _? p Q ^ a? r ? 'c^ ?` /r //''+????+I ? '{)('? -ate . 'm v ? . O a O m- 4 SSA \1' } ? n m :\-?• ?l- ?? .• I O ? ?_. n .` -,-,?..' `11¢11 • ? O ? W G .= I L N o ?, an; _. b 7C W t ' O ? • W. 10 O ? C ,Z `?.. 5 7 - [ ._ I = 1 %'• G' ? X40 O R 10 '. J .?Q N. c F 6 ... o off. ?1 e ?1 - $ C?'7 -?. _. 03 - W ?. G d :? Y /?'?'. 4 m a, - . G S ??? _ - c.-1 ••• Z O C it (n = I .:C? V 1 Q O m O C t ti OY C7 di GI 0 w _c 01 m W '^ ? m m I ? TY - f/!? Nm 1 m 1 1, 5. O m cE ,fir CZ CC" _ s I a v' _ •,? 1 > 01 m -- ,AE ? ? 67 6 ? 0p s. l 2_?3 _ _ ! u --?. s yt ! m v i> t v=i o V_ m .:. xn•.' ... - . d ° III p: w?/ -J _ ` 's a Iwo ?C n V G b 4 4-1 - C` . v ,p /ry -a 3? m y ?; m amv a,??^s r?'cr.??o .0 w If restoration is implemented on the Site, a detailed restoration plan will be prepared that includes stream geometry measurements and wetland characterization from a reference (relatively undisturbed) site in the region. Quantitative data collected during the design planning stage may affect mitigation activities proposed in this preliminary study. 4 1 2_0 RELEVANT FEATURES 2.1 PHYSIOGRAPHY, TOPOGRAPHY, AND LAND USE The Site is located in the southeastern corner of Guilford County, north of the Town of Liberty (Figure 1). This portion of the state is underlain by the Carolina Slate Belt geologic formation within the Piedmont physiographic province of North Carolina. The hydrophysiographic region is characterized by broad, rolling, interstream divides intermixed with steeper slopes along well-defined drainage ways (Figure 3). This region is characterized ' by moderately high rainfall with precipitation averaging 41 inches per year (NRCS 1977). ' The Site encompasses reaches of two streams including North Prong Stinking Quarter Creek and an associated unnamed tributary. Drainage areas for each of the streams are depicted in Figure 3. Drainage basin size ranges from approximately 5.8 square miles for North Prong Stinking Quarter Creek to approximately 1.0 square mile for the unnamed tributary at the respective Site outfall. The unnamed tributary and its adjacent floodplain represent the primary hydrologic feature of the Site. The unnamed tributary flows in a northerly direction for approximately 6300 linear feet through the Site prior to its convergence with North Prong Stinking Quarter Creek near the northern property boundary (Figure 3). The unnamed tributary is characterized as a second order stream extending through a relatively narrow, steeply sloped valley (approximately 0.006 rise/run [based on USGS 7.5 minute quadrangles]). As the unnamed tributary descends towards North Prong Stinking Quarter Creek, the valley widens and flattens to an average slope of approximately 0.0023 rise/run (based on USGS 7.5 minute quadrangles). The unnamed tributary watershed upstream from the Site is characterized mainly by agricultural land use (livestock, row crops, and hay production), low density residential development, and an airstrip / hanger complex associated with the Causey Airport facility. Impervious surfaces appear to account for less than 10 percent of the upstream land coverage. On-site land use is characterized by livestock and hay production. A residential structure and I complex of barns and hay storage structures are located centrally within the Site (Figure 4). The Site is primarily characterized by open pasture and agricultural fields with isolated hardwood forest stands. Pasture is heavily grazed by livestock with stocking rates of approximately 5 animal units per acre. Livestock have access to a majority of the Site. No exclusionary barriers occur adjacent to on-site streams or wetlands and livestock appear to have degraded stream banks and wetland soils. 5 I I(aill % 5.8 sq. Mi. / 1.0 sq. Mi. - t ?.. _ rL e7ii ? H CAUSEY FARMS ' MITIGATION SITE BOUNDARY f -. - f :. v' _ •:,E?z co .,9 ? RA, BOLYH '' -- - - _ _ ? v i EcoSCIence f'orporation Raleigh, North Carolina 27605 Client: Project: CAUSEY FARMS MITIGATION SITE GUILFORD COUNTY, NORTH CAROLINA Title: TOPOGRAPHY Dwn By: Date: MAF FEB2002 NORTH PRONG STINKING QUARTER CREEK WATERSHED 0 2000 ft. 4000 ft. 1:24.000 _ .'•2?J?. ' (?" _ Source: USGS 7.5 Minute Topo Maps (Climax. Kimesville. N.C.) - - ' 'i -- ? - -- ate- ?? .-•?..,?? :. . ?_????? « ?. T,T T,,,? ,????,- ,,,_, ,.. ...??.?.. _ . .. . UNNAMED TRIBUTARY -? WATERSHED Ckd By. Scale: WGL As Shown ESC Project No. 98-029 FIGURE i i i aT z v 1 r ,4 ? qs Imp I T m?„o- T 4'?„ VFI.b'3 o- r? " ' . 5;-, 7 x `? I n o- 3µ ?,A q,. y! '?y}Jt!. h °'?.h EE ??TG B? EcoScience Corporation Raleigh, North Carolina 27605 Project: CAUSEY FARMS MITIGATION SITE GUILFORD COUNTY, NORTH CAROLINA Title: v / .w y roC'?"?x i tx } a r e- ?, [ e , r, ei atW a W ' "` - .., "?? ai. ?h .' ?:+ ;.r • ?''bts `-? ,a..,..,, .. ._ ?;.' . ? ;a`?^?? `r-* ?:tU?,l:'a :.a"?. .nom, _?. FOREST v TIMBERED LAND BEAVER IMPOUNDMENT EXIST. STREAM CHANNELS PROJECT BOUNDARY LAND USE Dwn By. Dale: MAF FEB 2002 Ckd By: Scale: WGL As Shown Esc Project No 98-029 FIGURE 4 ' 2.2 VEGETATION The Site is characterized by pasture land with a few isolated forest stands. The Site is heavily grazed and / or receives regular vegetative maintenance and does not appear to be advancing past a secondary seral community. Riparian fringes have little vegetative cover and are dominated by species such as blackberry (Rubus argutas) and multiflora rose (Rosa multiflora). i Isolated patches of both hardwood forest and mixed pine forest occur in the floodplain south of Smithwood Road which bisects the property from west to east. Livestock have access to the mixed pine forest while the hardwood forest remains mostly fenced. The remaining forested communities are narrow strips of trees and shrubs growing along fence lines. The primary species are eastern red cedar (Juniperus virginiana), persimmon (Diospyros virginiana), f sweetgum (Liquidambar styraciflua), and Chinese privet (Ligustrum sinense). ' Pasture land dominates the Site and is characterized by native grasses with various invasive species such as pig weed (Chenopodium album), cocklebur (Xanthium strumarium), and ragweed (Ambrosia artemisiifolia). Patches of shrubby species occur adjacent to the streams and tributaries; however, these species have been bush hogged (mowed) or manually cleared. Shrubby species include blackberry, multiflora rose, black willow (Salix nigra), red maple (Acer rubrum), and sweetgum. Multiple wetland depressional areas support a wet herbaceous assemblage dominated by rushes and sedges (Juncus and Carex spp.). Reforestation of hardwood species may be achievable within the entire on-site floodplain complex. Forest species are expected to vary from bottomland hardwood forest to a more mesic levee mixed forest based on topographic variations. Species composition should mimic reference forest measurements of similar undisturbed floodplains in the region. An ecological approach to restoration is expected within the Site; therefore, a varied forest structure should target habitat diversity. 2.3 STREAM CHARACTERIZATION On-site streams have been characterization based on fluvial geomorphic principles (Rosgen 1996). Table 1 provides a summary of measured stream geometry attributes under existing conditions (considered to be unstable) and a preliminary estimate of potentially stable stream attributes. Establishment of specific design channel attributes will require measurement of a reference (relatively undisturbed and stable) stream reach within the hydrophysiographic region. Preliminary estimates of stable stream attributes are based primarily upon data observations along the existing reaches, regional curves (Harman et. al. 1999), and stream gauge data collected in stream gauges in the vicinity of the Site. 8 :-;-+�a-�f �:.'tiv '^ .h. :-�5„t. ��„ s��,_. �.. y,�,�...� E.. :.�• t .: r.� f„y g�.,ry�•,^ .. +,� '.n:�T'� ... F.-Ty,.. Fin'-s"; :" s � Jp {rE�EcoScien, Yip•. �•" ,+4`,y�i-f y+�}.,� i 1 1 Raleigh, North Carolina V �''� �+ is" y Y � a'..^ � .'�Y �•y1 it L'>��r���+�'ty � -s 3 ;>t� _ /°- Al-. y [ -0 C �• ` _ ��,..;:.. - ,`s,i } r: .; ,�F; '. ... ,y + �'It� i 3� ., t� yam.. y� rd��+� �,d:•. asl �: ear - t x 41 3 irkMITIGATIO SITE_ + �_ IL W NORTH i CAROL AWL -b 111A HYDRIC SOX log acres 7 HYDRIC SOILS 21 APIF7 BEAVER IMPOUNDMENT 1} q 11 ft. 0 •10 PROJECT BOUNDARY - - .. -� - - d .R •c µ. ' 2.3.1 Stream Classification Stream geometry and substrate data have been evaluated to orient stream restoration based on a classification, utilizing fluvial geomorphic principles (Rosgen 1996). This classification m classes associated with the Site include E, C, and G. Each stream type is modified by a ' number from one through six (example: C5) denoting a stream type which indicates a substrate dominated by 1) bedrock, 2) boulders; 3) cobble, 4) gravel, 5) sand, or 6) silt/clay. stratifies width/depth streams ratio, into sinuosity, comparable channel groups slope, based and on stream pattern, substrate dimension, profile, composition and substrate characteristics. Primary components of the classification include degree of . Strea entrenchment, Historically, on-site reaches may have been characterized as E4-type streams. E-type streams are characterized as slightly entrenched, riffle-pool channels exhibiting high sinuosity (> 1.5). In North Carolina, E-type streams often occur in narrow to wide valleys with well- developed alluvial floodplains (Valley Type VIII). E-type streams typically exhibit a sequence of riffles and pools associated with a sinuous flow pattern. E-type channels are typically considered stable. However, these streams are sensitive to disturbance and may rapidly convert to other stream types. Clearing of riparian vegetation, ditching and straightening activities, and hoof shear from livestock entering the channels, have resulted in bank collapse and erosion of on-site reaches. A majority of the on-site reaches are currently characterized as unstable, E/C- and E/G -type channels which are systematically entrenching (G-type) and widening (F-type) due primarily to the lack of deep rooted riparian vegetation. Bank materials are expected to continue to erode until a stable floodplain has been scoured at the current elevation of the disturbed streams. A majority of the unnamed tributary reach appears to have been dredged, straightened, and impacted by land clearing and livestock grazing. Grazing of livestock near stable streams (E stream-type) typically leads to channel adjustments including increases in bank erosion, width/depth ratio, stream gradient, and sediment supply. In addition, these impacts may lead to decreases in channel sinuosity, meander width ratio, and sediment transport capacity (Rosgen 1996). Straightening of channels induces erosion of bed and bank materials, which exasperates sediment transport problems. The unnamed tributary is expected to continue to erode and deposit sediment into receiving streams until a stable stream pattern has been _ carved from. the adjacent floodplain. 2.3.2 Dimension ' Regional curves (Harman et. a/. 1999) and field indicators of bankfull were utilized to determine bankfull channel cross-sectional area in on-site reaches. The cross-sectional areas 10 ' were then utilized to determine the bankfull width, average bankfull depth, maximum depth, and floodprone area of existing on-site channels. Using this method, a departure from stability could be estimated based on a comparison of existing and proposed (stable) dimension variables. Based on preliminary information, regional curves appear to overestimate the stable channel cross-sectional area at the Site. The existing North Prong Stinking Quarter Creek is characterized by a downstream cross-sectional area of approximately 38 square feet. This reach of the creek is classified as an E-type channel with a bank-height-ratio of 1.0. The channel does not exhibit excessive bank collapse and appears relatively stable. Regional curves indicate that a cross-sectional area of greater than 70 square feet is expected to occur in this reach. ' Regional curve comparisons to on-site cross-sectional data prompted a search of nearby stream gauges to verify the accuracy of regional curve predictions of bankfull discharge at the gauged site. Three gauged streams were identified which appear to represent similar drainage basin characteristics to the Site (Reedy Fork near Oak' Ridge, Rocky River at SR ' 1300, and Cane Creek Near Orange Grove). A peak annual discharge with a return interval of 1 .3 years has been utilized to predict bankfull discharge for this study. ' Regional curves predicted a 1.7 year return interval at two of the three gauges, indicating that regional curves may slightly overestimate bankfull discharge and bankfull cross-sectional area ' at the Site (gauge data is included in Appendix A). This information suggests that measurement of a nearby reference (relatively undisturbed) reach is imperative for the development of dimension variables to be constructed at the Site. However, for the purposes of this preliminary study, the regional curves have been utilized to predict stable channel dimension variables (Table 1). Based on regional curve estimations of cross-sectional area, it appears that various stream bank erosional scenarios occur on-site. The majority of the Site is characterized by channel incision which results in bank-height-ratios ranging from 1.0 to 1.5 (low bank height / bankfull height). The down-cut may have resulted from a lack of adjacent deep-rooted riparian vegetation. The down-cut has resulted in an incised channel that has begun to actively erode channel banks below the effective rooting depth of existing riparian vegetation. These channels are expected to widen, causing the stream type to migrate towards an F-type (widened gully) or disturbed C-type stream. However, until an active floodplain has been ' carved, the channel is expected to remain an unstable, narrow and deep, E/G-type channel. 11 ' Based on this assessment, measures designed to reduce the bank height ratio and widen the active floodplain are recommended along the channel. 2.3.3 Profile Based on USGS quadrangles, the on-site valley slope measures approximately 0.0023 rise r / run for North Prong Stinking Quarter Creek and 0.006 rise / run for the unnamed tributary. Estimated valley slopes appear typical for the Piedmont physiographic region of North Carlina. Water surface slopes were estimated by dividing the valley slope by channel sinuosity. Sinuosity was inferred from aerial photography and /or Global Positioning System technology. Sinuosity for North Prong Stinking Quarter Creek and its unnamed tributary were measured at 1.3 and 1.1, respectively. Calculated water surface slopes (Tables 1), range from approximately 0.0018 rise/run for North Prong Stinking Quarter Creek and 0.0055 rise / run for the unnamed tributary. Dredging and straightening of the unnamed tributary appears to have resulted in an over steepened water surface profile. Currently the water surface profile is approximately equal to the valley surface slope; 0.0055 versus 0.006 (Table 1). In addition, channel modifications have obliterated the riffle-pool morphology characteristics of stable streams in the region. Existing riffle slopes and pool slopes are, on average, outside the range of acceptable values considered for E-type streams in the region. An over steepened water surface slope may be detrimental to on-site channels due to increased erosive forces, altered secondary flow cells, and energy dissipation, possibly resulting in a step-pool channel morphology. Measures designed to reduce water surface slope and restore riffle-and pool-slopes to suitable ranges is expected to be targeted throughout the unnamed tributary. ' 2.3.4 Plan Form Aerial photography and in-field surveys were utilized to determine existing on-site plan form variables. Once the existing plan form variables were identified, they were compared to ratios ' of stable plan form variables based on fluvial geomorphic methods (Rosgen 1996). Using this method, a departure from stability could then be estimated. On-site channels support sinuosities ranging from between 1.1 to 1.3 (thalweg distance / valley distance). The unnamed tributary sinuosity (1.1) is considered low (based on ' geomorphic priciples) and North Prong Stinking Quarter Creek is considered moderate (1 .3). Stable sinuosities for E-type streams are expected to measure approximately 1.5. Reduced sinuosities may result from bank collapse, channel obliteration, and dredging and straightening of channels. The unnamed tributary exhibits a belt width that ranges from 38 to 112 feet 12 which is well below the expected range of 134 to 268 feet. The North Prong Stinking Quarter Creek belt width ranges from 228 to 342 feet and appears to represent stable pattern characteristics (based on regional curve estimates and reference ratios). On-site meander wavelengths average approximately 114 feet on the North Prong Stinking Quarter Creek but no distinct, repetitive pattern of sinuous riffle and / or pools were identifiable in the unnamed tributary due to straightening activities. A stable maximum wavelength for the unnamed tributary is expected to range between 94 to 160 feet with pool-to-pool spacings of approximately 54 to 80 feet (Table 1). Based on plan form variables, on-site channels include reaches that have been dredged and ' straightened or have been degraded by bank collapse and channel obliteration, thereby reducing the beltwidth, meander length, and sinuosity of the reach. Mitigation efforts ' targeting increases in sinuosity, beltwidth, and meander wavelength will be investigated along degraded sections to establish parameters within the range of potentially stable values for these attributes. 2.4 WETLANDS Jurisdictional wetlands are defined by the presence of three criteria: hydrophytic vegetation, hydric soils, and evidence of wetland hydrology during the growing season (DOA 1987). Portions of the Site historically supporting jurisdictional wetlands may have been characterized by palustrine, forested wetlands and groundwater seeps which were seasonally flooded. These wetland areas have been impacted by ditching, capping of spring heads, livestock ' trampling, deforestation, and groundwater draw-down from stream channel downcutting. Currently, on-site wetlands are characterized by a monoculture of sedges and rushes which ' are subjected to livestock trampling and heavy grazing pressure. Jurisdictional wetlands are underlain by alluvial soils of the Wehadkee series which occur in a large patch-like network ' throughout the on-site floodplains (Figure 5). Significant areas of jurisdictional wetlands occur adjacent to both the unnamed tributary and North Prong Stinking Quarter Creek. I Based on aerial photography and on-site investigations, approximately 21 acres of the floodplain currently are underlain by hydric soils that may have at one time supported jurisdictional wetlands. Down-cutting of stream channels and ditching of spring heads may have effectively lowered the adjacent groundwater table and soil saturation to below jurisdictional thresholds. In addition, livestock trampling and regular maintenance of agricultural fields have disturbed the natural state of these sensitive areas. Removal of livestock and planting with native forested vegetation may allow the floodplain to preform wetland functions such as flood-flow suppression, nutrient cycling, pollutant removal, and provide habitat for native species. 13 r r r r r r r r i r i r i F TABLE 1 STREAM GEOMETRY ATTRIBUTES CAUSEY FARM MITIGATION SITE Wbkfl D., lt Wb Wrpa BHR Wbkfl/ eve Abkfl (riffle) Aexist (riffle) SWB (rise/run) Salley (rise/run) Sin Substrate Stream Type Reach (Mies } (riffle) (riffle) e (ft) (ft) (ft) (ft) bank height ratio Mdth•depthratio (ft2) (ft2) (ft) (ft) Existing Stream Attributes, North Prong Stinking Quarter Creek, Piedmont Physiographic Province 55 0018 ,0023 1.3 1 0 66,1 . 3 23 4 2 278 323 114 57.4 . Average . . F 9 6-32 13 9-2.8 1 228-342 277-369 76186 38-93 -- -7 61,9 70,3 38 72 ------- --°°. Sand and Silt E/C Range 5.8 . . . .____ ._ Average X1S„,° 1.3 --- --- -°°"" ------• 13 15.2 5.4 2.7 ------ Average XIW?fl ------- 7 8 4 L8-4 ------- Range X1S„,° '•""'-" 11-16 13-17.3 . 3.6- . Range X/W fl bk Stable Attributes based on Regional Curves 0023 3 1 26 5 2 278 323 260 130 1,0 g 66.1 ------- .0018 . , Average . ------ 28 342 77 369 82 312 04 156 ------- 8-10 61.9-70.3 ----- """"-" ------- •------ Sand and Gravel E Range Range 5,8 ------ Average X/S„,° 4 12 10 5 ------- - Average X/Wbkfl ------- ------- 11 . __. __.. 6 ------- ------- Range X/S„,° -_•.•.- 2 7.13 8 10.6 14.1 7-12 4- Range XlWEkfl . . A Wbkfl BVg D Wb lt Wfia Lm LP•P BHR b/t)x„e Abkfl (riffles Aexlet (riffle) L Swe rise/run) S?euey ) (rise/ru in ubstrate tream Type Reach `h ? (mi i riffle) ( le) (ri ff e (ft) (ft) (ft) (ft) bank height ratio width•depth ratio (ft2) (ft2) (fits (ft) 7? Existing Stream Attributes, Unnamed Tributary, Piedmont Physiographic Province 1 1 F 1 2 8 20.9 40 .0055 .006 . A 12 1 5 42 99 . verage . No distinct, repetitive 1 6-15 7 3-1 7 1 38 112 80 117 pattern of riffles and 1.0.1.5 5-12 20-21.4 12.8-88 ------ ---•--- •°---- Sand and Silt E E1G Range . . . . pools due to ditching 1 1 -•-• 1.0 Average XIS„„ . ------- 3 5 8.3 and straightening ------ Average X/Wbkfl --•---- . activities Range X/S,,° Range XlWbkfl ------' ------ 3.2-9.3 6.7-10 Stable Attributes based on Regional Curves 1 5 009 ,006 . Average 13.4 1.6 200 99 134 67 1.0 9 20.9 ------- . ••-•--- -----•- Sand and Range 13.1-13,6 1,5-1.6 134-268 80-117 94-160 54-80 ------- 8.10 20-21.4 --- _ _ •-""•" Gravel E 1.0 10 5 ------- Average X1S„,° 1,5 -•- -- Average X/Wbkfl ______' __."___ 15 7.4 , 2 4-6 ------ ------- Range XIS,, 10 20 6-8.7 7-1 Range X/Wbkn 11 3_0 CONCEPTUAL MITIGATION PLAN The primary goals of this mitigation plan include: 1.) construction of a stable, riffle-pool stream channel; 2) enhancement of the water quality functions in the on-site, upstream, and downstream segments of North Prong Stinking Quarter Creek and its associated unnamed tributaries; 3) creation of a natural vegetation buffer along on-site stream channels; 4) restoration of wildlife habitat associated with a riparian corridor / stable stream; and 5) restoration of jurisdictional wetland hydrology to the floodplain of North Prong Stinking Quarter Creek and the unnamed tributary. Primary activities designed to restore the stream and wetland complex include: 1) stream restoration; 2) stream enhancement; 3) wetland restoration; and 4) vegetative community restoration (Figure 6). The mitigation concept outlined in Figure 6 is expected to restore approximately 6840 linear feet of stream and 5 to 7 acres of jurisdictional wetland, along with the subsequent enhancement of 3180 linear feet of stream and 14 to 16 acres of jurisdictional wetland. 3.1 STREAM RESTORATION Alternatives for stream restoration are designed to provide a stable stream channel and in- stream aquatic habitat while protecting the adjacent stream banks from extensive erosion. The alternatives proposed for this project are based primarily on professional judgement and potentially stable stream attributes characteristic of the region. ' The majority of the on-site stream channels are classified as E/G stream types. The cross- sectional area of on-site channels appear to have become unstable due to excessive bank ' erosion from deforestation, livestock trampling, and channel dredging / straightening. In addition, the bank height ratio of on-site channels, especially in the unnamed tributary, appears to have been elevated from 1.0 (stable stream channel) to between 1.0 and 1.5. ' Bank collapse, channel straightening, and erosion also appears to have reduced sinuosity of on-site channels to below the modal concept for stable E-type (highly sinuous) and C-type (moderately sinuous) streams in the region. Stream mitigation options should focus on the reduction of channel cross-sectional area (decreasing bank-height-ratio) and increasing sinuosity (reducing water surface slope). Stream mitigation activities which may be utilized to achieve these results include: 1) the construction of a channel on new location throughout most of the unnamed tributary; 2) bank stabilization and installation of grade control structures within secondary tributaries and North Prong Stinking Quarter Creek; and 3) the construction of bankfull benches near the upstream and ' downstream terminus of the Site. These mitigation activities are expected to result in ? 15 VEGETATIVE PLANTING AREAS BEAVER IMPOUNDMENT acres 45 EcoScience Corporation Raleigh, North Carolina 27605 Client: Project CAUSEYFARMS MITIGATION SITE GUILFORD COUNTY, NORTH CAROLINA Title: CONCEPTUAL MITIGATION PLAN own By. Date: MAF FEB2002 Ckd By: Scale: WGL As Shown ESC Project No.: 98-029 FIGURE 6 approximately 6840 linear feet of stream restoration and 3180 linear feet of stream enhancement (Figure 6). ' 3.1.1 Channel Construction on New Location Channel construction on new location is expected to occur predominantly in the unnamed tributary due to limited concerns of hydrologic trespass. Channel construction is expected to entail the preparation of a belt width corridor prior to channel excavation. Belt width ' corridor preparation will entail channel staking and any necessary grading prior to channel excavation. Spoil material excavated during the grading and channel excavation process is expected to be stockpiled adjacent to the existing unnamed tributary channel that will be ' abandoned and then backfilled. t Once belt width corridor preparation is complete, the proposed channel will be excavated to the average width, depth, and cross-sectional area derived from reference reach studies and detailed measurements of on-site streams. The stream banks and local belt width area of ' constructed channels will be immediately planted with shrub and herbaceous vegetation. Black willow shrubs may be removed from the banks of the abandoned channel and stockpiled during clearing to be replanted in the new stream channel. Root mats may also be selectively removed from adjacent areas and placed as erosion control features on channel ' banks. Particular attention will be directed toward providing vegetative cover and root growth along ' the outer bends of each stream meander. Available root mats or biodegradable, erosion control matting may be embedded into the break-in-slope to promote more rapid development ' of an overhanging bank. Willow stakes will be collected on-site and inserted through the root / erosion mat into the underlying soil. The reconstructed channel and vegetation will be allowed to stabilize for a minimum of four months during the growing season prior to ' diversion of flow. Flow will be diverted incrementally to allow for adaption within the reconstructed channel. ' 3.1.2 Bank Stabilization and the Installation of Grade Control Structures Bank stabilization may be performed along eroding outer bends within existing channel ' reaches of North Prong Stinking Quarter Creek, the hardwood forest section of the unnamed tributary, and two secondary tributaries entering the unnamed tributary from the east (Figure 6). Particular attention should be placed on outer bends of eroding pools or excessively ' eroding banks. Bank slopes will be protected through placement of appropriate structures such as brush mattresses, live brush layering, matting, rock toe protection, root wads, cross- vanes, and / or J-Hook vanes. 17 Grade control structures may be placed in the channel to elevate local water surface profiles in the channel, potentially flattening the water energy slope or gradient. The structures would ' likely consist of boulder-size rock vanes or step-pool devices designed primarily to direct stream energy into the center of the channel and away from actively eroding banks. In addition, the structures would be placed in relatively straight reaches to provide secondary r (perpendicular) flow cells during bankfull events. ' 3.1.3 Bankfull Bench Construction The potential excavation of a bankfull floodplain bench in North Prong Stinking Quarter Creek is expected to: 1) remove the eroding material and collapsing banks; 2) promote overbank flooding during bankfull flood events; 3) reduce the erosive potential of flood waters; and 4) increase the width of the active floodplain. After excavation, the bench would provide a ' relatively level floodplain surface which could be stabilized with suitable erosion control measures. Planting of the bench with native floodplain vegetation may reduce erosion of bench sediments, reduce flow velocities in flood waters, filter pollutants, and provide wildlife ' habitat. ' Floodplain benches may be constructed in North Prong Stinking Quarter Creek and reaches where hydrologic trespass may preclude increased water surface elevation. Stream reaches that may receive floodplain bankfull benches are located at the upper extent of on-site ' streams, near property boundaries, and at the Site outfall. ' 3.1.4 Ford Removal and Construction Several on-site fords have been identified in both the unnamed tributary and North Prong Stinking Quarter Creek. These existing fords have resulted in impoundment of on-site ' streams and obliteration of stream banks; therefore, removal of the fords is proposed within the Site. Replacement fords may be constructed to allow the passage of cattle and or ' vehicles. The fords are expected to consist of a shallow depression in the stream banks where vehicular crossings can be made. Flexibility in the location of the fords exists and may be changed upon request by landowners or on-site construction managers. The fords shall ' be constructed of hydraulically stable rip-rap or suitable rock and should be large enough to handle the weight of anticipated vehicular traffic. Approach grades to the fords should be ' approximately 30 feet in length and constructed of hard, weather-resistant crushed rock or other permeable material which is free of fines. The bed elevation should be equal to the bed elevation of the design stream channel above and below the fords to reduce the risk of headcutting. 18 t ' 3.2 WETLAND RESTORATION Alternatives for wetland restoration are designed to restore a fully functioning wetland system ' which will provide surface water storage, nutrient cycling, removal of imported elements and compounds, and will create a variety and abundance of wildlife habitat. Wetland restoration alternatives are based primarily on professional judgement and a reference wetland is r expected to be measured to determine vegetative features, micro- and macro- topographic variations, and soil structure components to be targeted during development of the Site. ' Portions of the Site underlain by hydric soil have been impacted by ditching of natural springs, channel incision, vegetative clearing, livestock grazing, and earth movement associated with ' agricultural practices. These areas are characterized by a near mono-culture community of sedges, grasses, and rushes, under severe impact from soil compaction by livestock ' trampling. Wetland mitigation options should focus on the restoration of vegetative communities, elevating groundwater tables to jurisdictional conditions, and the re- establishment of soil structure and micro-topographic variations within the existing floodplain. Restoration of wetland hydrology and wetland soil attributes may' involve: 1) excavation and ' grading of elevated spoil and sediment embankments; 2) placement of impervious channel plugs along abandoned reaches; 3) backfilling of entrenched stream reaches; and 4) scarification of pasture soils prior to planting. In addition, the construction of (or provisions ' for) surface water storage depressions (ephemeral pools) also adds an important component of groundwater restoration activities. These mitigation activities are expected to result in the ' restoration of approximately 5 to 7 acres and enhancement of approximately 14 to 16 acres of jurisdictional wetland at the Site. 3.3 VEGETATIVE PLANTING Deep-rooted, riparian vegetation will be restored within the entire floodplain complex of both ' the unnamed tributary and North Prong Stinking Quarter Creek. Planting vegetation on cleared stream banks is proposed to re-establish vegetation community patterns within the stream corridor, associated side slopes, and transition areas. Vegetating the floodplain and ' stream banks is expected to provide stream bank stability, shade and cool surface waters, filter pollutants from adjacent runoff, and provide habitat for area wildlife. The vegetated ' stream buffer will extend to a minimum of 50 feet on both sides of the stream. Scarification of floodplain surfaces will be required prior to vegetation planting. ' Variations in vegetative planting may occur based on topographic locations and hydraulic conditions of the soil. Vegetative species composition should mimic reference forest data and ' on-site observations. Species expected for this project may include the following elements. 19 Shrubs I Trees 1. Green Ash (Fraxinus pennsylvanica.) 2. Northern Red Oak (Quercus rubra) 3. American Sycamore (Platanus occidentalis) 4. 5. American Elm (Ulmus americana) Ironwood (Carpinus caroliniana) 6. Black Cherry (Prunus serotina) 7. Smooth Black Haw (Virburnum prunifolium) 8. Black Gum (Nyssa Sylvatica) Stream-Side Assemblage 1 . Black Willow (Salix nigra) 2. Box Elder (Acer negundo) 3. Ironwood (Carpinus caroliniana) ' 4. 5 River Birch (Betula nigra) American Sycamore (Platanus occidentalis) . ' Stream-Side Shrub Assemblage 1. Tag Alder (Alnus serrulata) ' 2. 3. Buttonbush (Cephalanthus occidentalis) Elderberry (Sambucus canadensis) 4. Arrow-wood Viburnum (Viburnum dentatum) ' 5. Possumhaw Viburnum (Viburnum nudum) 6. Bankers Dwarf Willow (Salix cotteli) ' 7. Black Willow (Salix nigra) Approximately 45 acres of on-site floodplain is expected to be re-vegetated during mitigation ' construction. Species distribution and densities are expected to be determined during the detailed mitig ation planning phase of the project. 1 20 1-1 r 4_0 MONITORING PLAN Monitoring of Site restoration efforts is expected. to be performed until success criteria are ' fulfilled. A monitoring plan and detailed success criteria are expected to be developed during the detailed mitigation planning phase of the project. However, some guidelines which may be utilized to develop a monitoring strategy and success criteria follow. r 4.1 STREAM MONITORING Annual fall monitoring may include development of a channel plan view, channel cross- sections on riffles and pools, pebble counts, and a water surface profile of the channel. The data may be presented in graphic and tabular format. Data to be presented is expected to include: 1) cross-sectional area; 2) bankfull width; 3) average depth; 4) maximum depth; 5) width / depth ratio; 6) meander wavelength; 7) belt width; 8) water surface slope; 9) sinuosity; and 10) stream substrate composition. The streams should subsequently be classified according to stream geometry and substrate (Rosgen 1996). Significant changes in channel morphology are expected to be tracked and reported by comparing data in each ' successive monitoring year. ' 4.2 STREAM SUCCESS CRITERIA Success criteria for stream restoration may include: 1) successful classification of the reach as a functioning stream system (Rosgen 1996); 2) channel stability indicative of a stable stream system; and 3) development of diagnostic biological communities over time. t The channel configuration may be measured on an annual basis to track changes in channel geometry, profile, or substrate. These data are expected to be utilized to determine the success in restoring stream channel stability. Specifically, the width / depth ratio should ' remain at or below a value of 14 in each monitoring year. In addition the channel should not become incised relative to the adjacent floodplain. Modifications to the channel should be performed to increase or, decrease the sediment transport capacity, or other unstable attributes, as needed. If the stream channel is down-cutting or the channel width is enlarging due to bank erosion, additional bank or slope stabilization methods may be employed. 4.3 WETLAND MONITORING Groundwater gauges are expected to be installed in accordance with specifications in U.S. Corps of Engineers', Installing Monitoring Wells/Piezometers in Wetlands (WRP Technical Note HY-IA-3.1, August 1993). Monitoring gauges should be set to a predetermined depth of ' approximately 40 inches below the soil surface in order to obtain a more accurate depiction of watertable fluctuations. Hydrological sampling may be performed on-site and within ' reference areas throughout the year to compare pre- and post-construction conditions. 21 r 4.4 WETLAND SUCCESS CRITERIA Target hydrological characteristics may include a minimum regulatory wetland hydrology criteria based upon reference groundwater modeling. Evaluation of success criteria is expected to be supplemented by groundwater gauge data and comparison between restoration and reference areas. Target hydrological characteristics during years with average rainfall include saturation or ' inundation (free water) within one foot of the soil surface for at least 12.5 percent of the growing season. Upper landscape reaches and hummocks within wetland areas may exhibit surface saturation / inundation between 5 percent and 12.5 percent of the growing season. These 5 to 12.5 percent areas are expected to support hydrophytic vegetation within hydric soils. If wetland parameters are marginal as indicated by vegetation and hydrology monitoring, consultation with U.S. Army Corps of Engineers (COE) personnel will be undertaken to determine jurisdictional extent in these areas. e 4.5 VEGETATION MONITORING Restoration monitoring procedures for vegetation are expected to'be designed in accordance with U.S. Environmental Protection Agency (EPA) guidelines enumerated in (EPA 1990) and (DOA 1994). A general discussion of the restoration monitoring program is provided. After planting has been completed in winter or early spring, an initial evaluation may be performed to verify planting methods and to determine initial species composition and density. Supplemental planting and additional site modifications are expected to be implemented, if necessary. During the first year, vegetation should receive cursory, visual evaluation on a periodic basis to ascertain the degree of overtopping of planted elements by nuisance species. Subsequently, quantitative sampling of vegetation should be performed between September 1 and October 30 after each growing season until the vegetation success criterion is achieved. During quantitative vegetation sampling in early fall of the first year, sample plots may be randomly placed within the Site. In each sample plot, vegetation parameters to be monitored may include species composition and species density. Visual observations of the percent cover of shrub and herbaceous species are expected to be recorded. 22 ' 4.6 VEGETATION SUCCESS CRITERIA Success criteria have been established to verify. that the vegetation component supports community elements necessary for floodplain forest development. Success criteria may be dependent upon the density and growth of characteristic forest species. Guidelines including survivorship of approximately 320 stems per acre in the first three monitoring years may be utilized. Subsequently, 290 character tree species per acre may be surviving in year 4, and 260 tree species per acre in year 5. Planted species should represent a minimum of 30 percent of the required stem per acre total (96 stems/acre). Each naturally recruited character species may represent up to 10 percent of the required stem per acre t total. In essence, seven naturally recruited character species may represent a maximum of 70 percent of the required stem / acre total. Additional stems of naturally recruited species ' above the 10 percent - 70 percent thresholds are discarded from the statistical analysis. If vegetation success criteria are not achieved based on average density calculations from. combined plots over the entire restoration area, supplemental planting may be performed with tree species approved by regulatory agencies. Supplemental planting may be performed as , needed until achievement of vegetation success criteria. No quantitative sampling requirements are proposed for herb assemblages as part of the vegetation success criteria. Development of floodplain forests over several decades are expected to dictate the success in migration and establishment of desired understory and groundcover populations. Visual estimates of the, percent cover of herbaceous species and photographic evidence may be reported for information purposes. 4.7 CONTINGENCY In the event that vegetation, hydrology, and / or stream success criteria are not fulfilled, a mechanism for contingency may be implemented. For vegetation contingency, replanting and extended monitoring periods will be implemented if community restoration does not fulfill minimum species density and distribution requirements. Stream reconstruction failure may occur due to increased sediment and discharge during development within the upper watershed. Stream contingency will likely include identification and modification of upstream sediment sources, additional stabilization of stream banks, and re-establishment of stream substrates required to support target aquatic communities. Recommendations for stream contingency will also be solicited, implemented, and monitored until the Stream Success Criteria are achieved. 23 Wetland hydrology failure may occur due to insufficient hydrologic flow and or unpredictable hydraulic conductivities of disturbed soils. Wetland contingency may likely include modifications of floodplain and or subsurface soils required to support target hydrologic regimes. r Recommendations for vegetation, stream, and wetland contingency is expected to be solicited, implemented, and monitored until the Success Criteria are achieved. 5.0 DISPENSATION OF PROPERTY Restoration Systems will maintain the conservation easement within the Site until all mitigation activities are completed and the mitigation site has been deemed successful. Once the Site has been developed, the easement may be deeded to a land trust organization or community entity suitable to the regulatory agencies. A likely candidate for perpetual maintenance of the easement is Guilford County. The Site may be incorporated into the Guilford County Division Parks and Recreation for use in environmental education and / or open space. The current landowner (Mr. Trager) is expected to retain ownership of the properties. The conservation easement is expected to be transferred perpetually with the properties upon sale or development of the property. Covenants and / or restrictions on the deed will be included t that will ensure adequate management and protection of the Site in perpetuity. 1 24 6.0 REFERENCES Department of the Army (DOA). 1987. Corps of Engineers Wetlands Delineation Manual. Tech. Rpt. Y-87-1, Waterways Experiment Station, COE, Vicksburg, MS. Department of the Army (DOA). 1994. Corps of Engineers Wilmington District. Compensatory Hardwood Mitigation Guidelines (12/8/93). Environmental Protection Agency (EPA). 1990. Mitigation Site Type Classification (MIST). EPA Workshop, August 13-15, 1989. EPA Region IV and Hardwood Research Cooperative, NCSU, Raleigh, North Carolina. ' Harman, W.A., G.D. Jennings, J.M. Patterson, D.R. Clinton, L.A. O'Hara, A. Jessup, R. Everhart. 1999. Bankfull Hydraulic Geometry Relationships for North Carolina Streams. N.C. State University, Raleigh, North Carolina. Natural Resource Conservation Service (NRCS). 1977. Soil Survey of Guilford County, North Carolina. U.S. Department of Agriculture. Rosgen, D. 1996. Applied River Morphology. Wildland Hydrology (Publisher). Pagosa Springs, Colorado. Rosgen, D. 1996b. "Classification of Natural Rivers: Reply to the comments by J.R. Miller and J.B. Ritter." Catena. 27:301-307 25 r I 1 APPENDIX A STREAM GAUGE DATA t fl Peak Streamflow Reedy Fork Near Oak Ridge, NC USGS Station #02093800 Drainage Area 20.6 square miles Return Water Discharge Exceedance Exceedance Interval Year (cfs) Probability Probability % (years) 1 1960 3950 0.02 2 46.0 2 1972 2990 0.04 4 23.0 3 1979 2880 0.07 7 15.3 4 1978 2350 0.09 9 11.5 5 1996 2330 0.11 11 9.2 6 1984 2090 0.13 13 7.7 7 2000 2050 0.15 15 6.6 8 1997 1880 0.17 - 17 5.8 9 1993 1590 0.20 20 5.1 10 1969 1500 0.22 22 4.6 11 1959 1460 0.24 24 4.2 12 1991 1440 0.26 26 3.8 13 1989 1310 0.28 28 3.5 14 1973 1250 0.30 30 3.3 15 1987 1250 0.33 33 3.1 16 1965 1210 0.35 35 2.9 17 1977 1210 0.37 37 2.7 18 1975 1040 0.39 39 2.6 19 ' 1982 995 0.41 41 2.4 20 1986 965 0.43 43 2.3 21 1963 960 0.46 46 2.2 22 1974 957 0.48 48 2.1 23 1990 952 0.50 50 2.0 24 1992 864 0.52 52 1.9 25 1970 858 0.54 54 1.8 26 1994 837 0.57 57 1.8 28 1962 . 756 0.61 61 1.6 29 1958 746 0.63 63 1.6 30 1998 741 0.65 65 1.5 31 1971 729 0.67 67 1.5 32 1957 719 0.70 70 1.4 33 1980 670 .,0.72 72 1.4 34 1966 664 0.74 74 1.4 35 1983 664 0.76 76. 1.3 37 1995 582 0.80 80 1.2 38 1981 517 0.83 83 1.2 39 1999 412 0.85 85 1.2 40 1961 408 0.87 87 1.2 41 1964 388 0.89 89 1.1 42 1976 379 0.91 91 1.1 43 9985 378 0.93 93 1.1 44 1988 148 0.96 96 1.0 45 1967 147 0.98 98 1.0 J am F Ltt cz PLed 4, GA C 0- I- I I Peak Streamflow Cane Creek Near Orange Grove, NC USGS Station #02096846 Drainage Area 7.5 square miles Return Water Discharge Exceedance Exceedance Interval Year (cfs) Probability Probability % (years) 1 1996 2060 0.08 8 13.0 2 1993 1740 0.15 15 6.5 3 1995 1280 0.23 23 4.3 4 1998 1110 0.31 31 3.3 5 2000 903 0.38 38 2.6 6 1989 864 0.46 46 2.2 7 1994 725 0.54 54 1.9 8 1999 689 0.62 62 1.6 9 1991 516 0.69 69 1.4 10 1997 458 0.77 77 1.3 TT 1992 433 0.85 85 1.2 12 1990 421 0.92 92 1.1 ab a< k t I Peak Streamflow Rocky River at SR1300 Near Crutchfield Crossroads, NC USGS Station #0210166029 Drainage Area 7.4 square miles Return Water Discharge Exceedance Exceedance Interval Year (cfs) Probability Probability % (years) 1 1998 864 0.08 8 12.0 2 1995 698 0.17 17 6.0 3 1997 673 0.25 25 4.0 4 1991 469 0.33 33 3.0 5 1994 429 0.42 42 2.4 6 1999 427 0 50 _ 50 2.0 7 1989 395 0.58 58 1.7 ,? V L 8 1993 340 0.67 67 1.5 Teppt i c , Cave ?'` 9 1990 256 0.75 75 1.3 Dr.?vt k } 10 1 2 238 0.83 83 1.2 11 2000 201 0.92 92 1.1w?t:ud APPENDIX B ON-SITE CROSS-SECTIONAL DATA 11, I r i I I I I I I I M a w u m Q N m li N Q L V V? r O Cl) CO) O i N J ? O tv s ¢ 3 -?- "N''i *"NmmniloLrre,.,Im"",",O??,,?.w;??lI W VI N M ?) I I - . W; - 'IN I I I I I I I I ,, o r LO N LO M U) d- LO LO M O co uw) N O N LO T- 3 'Xj I r 1 ' N a- .3 II NL t 11 Y" t? ?i A LO LO _ ?? 4Sj?,y4 irat'e` Y ?;•y ' ea? 7?tk UO) r., _ 11 NMI .: t I S? , NEW om . t . Y V O Ln t/1 M N ? ,- p .i O L Z, a.S M t v? w I N ? N D ? J Q. S i s ?l O Q LL w ?? T' I Rv.n V? Y• ? ?.- .. ?,?46 0?.? .r Ji, ?,,F. aril' ni. ?v ,?7?I O O L" LO N Lf) M LO d' LC) LO 3 A A 3 O r N C'7 ?' r 1 1 1 1 N u N ?I h Arr ? Q`-i ? Y pt A V / h C? L ur! z Cl) O O C ? O V to U) Lid y rl Ir w 0 rl V LL z i J ? M fir;„v;? ? ? _d 1 ? I r? I? r I? O { a O r- Lo N U) co In a fl 3 O r N ' m r z `i ' k t a• t{ ?$ M r' ? tl Q J M AL m q O M 6 rg9k L / N PONIZISIZ O Y - BFI CO w o LO y. 'rf 9 O ¦ L 4- U ^^+ W O O tl V LO '? It v {y w N t O U r- LO NU-) M LO d- LO ,, t ? C ; 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 d L V cn Q F- Ul) r. O co d y a 0 ? a? U o ? I ' s ?I ?I I tt -6 co LL r ?i II ?? fl O co N O N LD r O O T- N M d' LO (D 1 u n n 1 0 CONCEPTUAL MITIGATION REPORT CAUSEY FARM MITIGATION SITE GUILFORD COUNTY, NORTH CAROLINA Prepared for: Restoration Systems 1101 Haynes Street, Suite 203 Raleigh, North Carolina 27604 Prepared by: EcoScience EcoScience Corporation 1101 Haynes Street, Suite 101 Raleigh, North Carolina 27604 February 2002 R NOV ?i 3 20'03 RALEIGH REGULATORY FIELD OFFICE fl fl 11 u MACTEC November 3, 2003 Ms. Jean B. Manuele, Chief Raleigh Regulatory Field Office U.S. Department of the Army Wilmington District Corps of Engineers Regulatory Division P.O. Box 1890 Wilmington, NC 28402-1890 Attention: Mr. John Thomas RECEIVED NOV 0 3 2003 RALEIGH REGULATORY FIELD OFFICE Subject: Proposed Revision to Off-Site Component of Mitigation Plan for Piedmont Triad International Airport Section 404 Action ID No. 200021655 Section 401 Water Quality Certification No. 3428 Dear Ms. Manuele: Pursuant to discussions of October 30, 2003 on behalf of the Piedmont Triad Airport Authority (PTAA, applicant) we are hereby requesting your formal concurrence that the three off-site stream restoration components located in Burlington (2,510 linear feet total), of the Wetland and Stream Mitigation Plan for the referenced project, be replaced by an equal linear footage of additional stream restoration at the Causey Farm site (to total 5,910 linear feet, if approved). It is anticipated that the contiguous Causey Farm stream restoration project will provide better success potential and more appropriate functional replacement for stream impacts than. the relatively short, separate Burlington stream segments constrained by utilities, landfill, parklmunicipal ordinances, adjacent landowners, and public use. We respectfully request that the attached Conceptual Mitigation Report replace the Burlington and previously submitted Causey Farm components of the Wetland and Stream Mitigation Plan for this project. Please do not hesitate to contact me regarding the proposed revisions to the off-site mitigation component. Sincerely, MACTEC ENGINEERING AND CONSULTING, INC. Richard B. Darling, C.E Principal Environmental Scientist Enclosures: Conceptual Mitigation Report for Causey Farm Mitigation Site cc: Mickie L. Elmore, PTAA. Kevin J. Baker, Baker & Associates. RBD/KJB/MLE:rbd P:W401 M Pmjac =253 MAVKodd'i=Wn\RgU st Modification Ldoc MACTEC Engineering and Consulting 3301 Atlantic Avenue • Raleigh, NC 27604 919-876-0416 • Fax: 919-831-8136 ' TABLE OF CONTENTS Paae I ' LIST OF APPENDICES, FIGURES, AND TABLES ........................... . ii 1.0 INTRODUCTION ............................................ 1 2.0 RELEVANT FEATURES ........................................ 5 ' 2.1 Physiography, Topography, and Land Use ...................... 5 2.2 Vegetation ........................................... 8 2.3 Stream Characterization .................................. 8 ' 2.3.1 Stream Classification .............. 10 2.3.2 Dimension ...................................... 10 2.3.3 Profile ......................................... 12 2.3.4 Plan Form ....................................... 12 I' 2.4 Wetlands ........... ..... ............... ......... 13 0 3 CONCEPTUAL MITIGATION PLAN ................................ 15 ' . . 15 I ...... 3.1 Stream Restoration ... ................ ....... 3.1.1 Channel Construction on New Location .................. 17 t 3.1.2 Bank Stabilization and Grade Control Structures ............. 17 3.1.3 Bankfull Bench Construction 18 1.4 Ford Removal and Construction .......... ...... ..... 3 18 I' . 3.2 Wetland Restoration .................................... 19 3.3 Vegetative Planting ..................................... 19 . . 21 4.0 ......... . MONITORING PLAN ............................. I, 4.1 Stream Monitoring ...................................... 4.2 Stream Success Criteria ........ .... ...................... 21 21 4.3 Wetland Monitoring ................ ........ • • • • . • • . • • .. 21 I 4.4 Wetland Success Criteria 22 ' `` ::::::::::::::::::: : :::::::: : :: 4.5 Vegetation Monitoring . • 22 Vegetation Success Criteria ............................... 4.6 23 ' . 7 Contingency .........................................: 4 23 . ' 5.0' DISPENSATION OF THE PROPERTY .......... ...... • • • • • • ... • • • 24 6.0 REFERENCES ............................................... 25 ?ll 0 1 i i i i i LIST OF FIGURES Figure 1: Site Location ...................... ................... 2 Figure 2: Service Area ....................... ................... 3 Figure 3: Topography ....................... ........... ..... . 6 Figure 4: Land Use ......................... .................... 7 Figure 5: Hydric Soils ........ ............... ..... ............. 14 Figure 6: Conceptual Mitigation Plan .. ......... ................... 16 LIST OF TABLES Table 1: Stream Geometry Attributes` .. ............................ 9 APPENDICES Appendix A: Stream Gauge Data Appendix B: On-Site Cross Section Data 1 A t CONCEPTUAL MITIGATION REPORT CAUSEY FARM MITIGATION SITE ' GUILFORD COUNTY, NORTH CAROLINA 1.0 INTRODUCTION ' Restoration Systems is currently evaluating stream and wetland restoration potential at a site located in southeastern Guilford County, approximately 5 miles north of the Town of Liberty ' (Figure 1). The Causey Farm Mitigation Site encompasses approximately 288 acres of land which is currently utilized for livestock grazing and hay production. Streams and wetlands within the property have been cleared of native forest vegetation and are accessible to t livestock, resulting in local disturbance to stream banks and wetland soil surfaces. ' The Site is located in U.S. Geological Service (USGS) Hydrological unit #03030002 of the Cape Fear River Basin (Figure 2). This portion of the Cape Fear River Basin encompasses portions of Guilford, Rockingham, Caswell, Alamance, Orange, Chatham, and Durham Counties. Towns potentially serviced by this mitigation project include Greensboro, Burlington, Reidsville, and Chapel Hill. The Site is intended to be developed to provide stream ' and riverine wetland mitigation credit to various projects in the region. The purpose of this study is to determine potential restoration alternatives on the Causey Farm Mitigation Site (hereafter referred to as the "Site"). This study is designed to address the following objectives: 1 Provide plan views of the Site including land use constraints, topographic ' ) features, wetlands, existing vegetation, or other features that may effect the restoration project. 2) Classify on-site streams according to fluvial geomorphic attributes measured ' within each reach. 3) Develop a preliminary, conceptual plan of potential stream and wetland mitigation activities. 4) Determine a monitoring strategy including mitigation success criteria. 5) ....Assess potential managers for the Site once mitigation activities are complete. ' This document is intended to provide information to agency personnel for discussion of project parameters, including Site suitability and mitigation options / activities. Potential restoration alternatives have been presented based primarily upon professional judgement. 1 f. F F i ht i.?P>wtc ' I y) Vill ,•? r Ti ??Q? 2? s'Pa,a Ate- 1 s l? 1 r(I L' y?; ?. UIQ 87 ` \ 5¢ddha - w l z ` 4-..'?`u"'°`'I •r, e e a,lar?eiH .?c-.. I a5? ''\ '` .. ?l \ r.?-._.•c?.e. gel`'?.`}_. -w ao _ eya I ?w?a` . M1.y \ l F<t f _ i, JJ•'F ? 6 nglJ"A I C' ty?!a eC/-; _ _? a ? ? i s ? ?.ov ' ,warm ?xrxt>;'?,11 ,.,? ?\ :r? `•b. - ?: o? i I ? 1 - 1 Alb'endnCC . , J'- I , 1_" s I re x ao ?, e - .QR BatdC>grour ?a e, 49 \? -r'y- c1t?, 1 M 'y •T eUrpdv b i,oon C'VIje - ?'_Z 'e0.gr„ - a ?? y °'' - $ e? 1 ,yv+l ., x_^ .r, v • 2avxn, CAUSEY FARM ! ,,ate' Any4 MITIGATION ;i' - - - r nta, SITEc, R° - cane weegl 1- S- L5 s; } W r•) { r ds ? I. I r 1 ba e??? ?' j dF I xc eFO?,{c :?> ?% ?-4wr g-, ? -J V I? S \ 3i I . C sq, R,j C ° , S d 9 de-,60 ? m 421 I I I ? ti ? • ' ?\"00? I c ?? ? a 4 , ? qr. 1 ..: -ZI n Lrrwpe c ?N µ x ® !kr'G a -_ l "'" ,b U A° A. 0 1 mi. 4 mi. .\ '-. ° x m 1:158.400 ? Source: 1977 North Carolina Atlas and Gazetteer, p.38. I a ? I ? I. sws -nt QrreY, J ? v \! - rycT W.f ? 0v v / j n ?reenap ? ?<x. ? . _ lMmax ? ? J.. CL w Cli ? I o } z 4 C? Dwn. by: MAF SITE LOCATION Ckdby: FIGURE E>`'t?SC7CDCi WG L Co poi-wk)n CAUSEY FARM MITIGATION SITE Date: 1 Raleigh, North Carolina Guilford County, North Carolina Project: FEB 2002 I 98-029 C t t a,^ ?Z >: t W r` Z W N N ` m Q O Z J IL ?" _ = u. C) U Q ti LL .. Q W C c7 ?W oV ?W o h rn LL 0 U) 0 ? W Q 3 LL C - =)C JO U 3 73 (9 z U - a` U F o [) w N/? f o i. c m_ O ?.?1•/-3 ac c 6;n g cc a a _ - _ c y: a ? l:'--^?4' m ? a ? '_CY ? _ ---•-_- _J. c ? _mx ? U Z (7 ?-O Q ?s ?yr1y! % L m a \1A?Iv .. _ y _ ?' 3 o l f0 N ?-- - t - c 00 \Y ti j O m L r? % ----??- -o- --=-i--'- '- ------?- -? --.... ?-: yeti pit _r?- --- o •}'U- - P U V O T I -?i L ?` "? 4 0- - - p c L v n m c e G cu n J >-?.?.i: I G O LIV gym yT ...aC. vo or-• _ i.: ?T( c `l o cu o_ o - c. T-1 m - - -- - ; _ - 1 . E y - 1 Y a' ce lr ?L`Q l fi..+ o F. Wan d N 3`, IS it" lo ui L aC 9 ra > v .. Vl ( s > o` a m C c 1 c a - ro cos , : E Al C x c m. ro y ° Q ! `' k `' a ,-.? S m E ( Si".' c•?*r? - ? I - tea' OC -^z ra, a a '-? ... a ® w I uc_ U o 1 WWWWWW? --? m L? - L!2z 7. i 5 1 o = 1. "7 if) .::Y?' 3??X'+ ?•J.x` 4 e c u n ?n Q $ "". ? •- . ;.: -.1 V co 'pm 9 -c.... S V <? 113 z m m ?"_? _wr`,.•?-?• _ G ` _? - ?__y 3 ?t ? art v I ? o ?t c w c ?`•77--• o m 1.J ? Q ? 3 m ?• ` ? W _ o 0 C??•^,,? f C m ?. /)I? ??y, L Y 1 y' ' If restoration is implemented on the Site, a detailed restoration plan will be prepared that includes stream geometry measurements and wetland characterization from a reference (relatively undisturbed) site in the region. Quantitative data collected during the design ' planning stage may affect mitigation activities proposed in this preliminary study. 4 1 F 7? r i? I 2_0 RELEVANT FEATURES ' 2.1 PHYSIOGRAPHY, TOPOGRAPHY, AND LAND USE The Site is located in the southeastern corner of Guilford County, north of the Town of _ Liberty (Figure 1). This portion of the state is underlain by the Carolina Slate Belt geologic ' formation within the Piedmont physiographic province of North Carolina. The hydrophysiographic region is characterized by broad, rolling, interstream divides intermixed with steeper slopes along well-defined drainage ways (Figure 3). This region is characterized by moderately high rainfall with precipitation averaging 41 inches per year (NRCS 1977). The Site encompasses reaches of two streams including North Prong Stinking Quarter Creek and an associated unnamed tributary. Drainage areas for each of the streams are depicted in Figure 3. Drainage basin size ranges from approximately 5.8 square miles for North Prong Stinking Quarter Creek to approximately 1.0 square mile for the unnamed tributary at the respective Site outfall. The unnamed tributary and its adjacent floodplain represent the primary hydrologic feature of the Site. The unnamed tributary flows in a northerly direction for approximately 6300 linear feet through the Site prior to its convergence with North Prong ' Stinking Quarter Creek near the northern property boundary (Figure 3). The unnamed tributary is characterized as a second order stream extending through a relatively narrow, steeply sloped valley (approximately 0.006 rise/run (based on USGS 7.5 minute quadrangles]). As the unnamed tributary descends towards North Prong Stinking Quarter Creek, the valley widens and flattens to an average slope of approximately 0.0023 rise/run (based on USGS 7.5 minute quadrangles). The unnamed tributary watershed upstream from the Site is characterized mainly by agricultural land use (livestock, row crops, and hay production), low density residential development, and an airstrip / hanger complex associated with the Causey Airport facility. Impervious surfaces appear to account for less than 10 percent of the upstream land coverage. On-site land use is characterized by livestock and hay production. A residential structure and complex of barns and hay storage structures are located centrally within the Site (Figure 4). The Site is primarily characterized by open pasture and agricultural fields with isolated hardwood forest stands. Pasture is heavily grazed by livestock with stocking rates of ' approximately 5 animal units per acre. Livestock have access to a majority of the Site. No exclusionary barriers occur adjacent to on-site streams or wetlands and livestock appear to ' have degraded stream banks and wetland soils. n G n u 1 1 i- .. . ? ?? l 371 - 5.8 sq. Mi. J. . ci! a -- 1.0 sq. Mi. JI y ? ? HF EcoScience Corporation Raleigh, North Carolina 27605 Client: Project: CAUSEY FARMS MITIGATION SITE GUILFORD COUNTY, NORTH CAROLINA Title: TOPOGRAPHY Dwn By 0 2040 N. 4000 It. L -? 1:24,000 Source: USGS 7.5 Minute Topo Maps (Climax. Kimesville. N.C.) ?f NORTH PRONG STINKING QUARTER CREEK WATERSHED UNNAMED TRIBUTARY WATERSHED MAF FEB 2002 Ckd By: Scale: WGL As Shown ESC Project No.: 98-029 FIGURE I? II? 3 I 1? I I I I I I I I I I I I I I I I I r i Ilk - ?T y ? - 1;tT 1 ? t,m c ?u i 8 Y 1 II kro i AM7A ?r x t 3 f Fe EcoScience Corporation Raleigh, North Carolina 27605 Client: ?y I Project: CAUSEYFARMS MITIGATION SITE GUILFORD COUNTY, NORTH CAROLINA ? ? t c ' +I 'CL' a h a y ' S W.„ A'?: taw: ,? a W .eX?5, Fe r ?Lq J w A ? f p* ' _ '?.'M xw,F? ? ? y - f it ,__" l1'LIV tl.Y LL 9k 'P'?? 1G }4h j' a L d "F"` 4!?r(i µu S Illdil?iiA Title: LAND USE Dwn By. Dale: MAF FEB2002 Ckd By: Scale: WGL As Shown ESC Project No 98-029 FIGURE 4 0 ' 2:2 VEGETATION The Site is characterized by pasture land with a few isolated forest stands. The Site is ' heavily grazed and / or receives regular vegetative maintenance and does not appear to- be advancing past a secondary seral community. Riparian fringes have little vegetative cover and are dominated by species such as blackberry (Rubus argutas) and multiflora rose (Rosa ' multif/ora). ' Isolated patches of both hardwood forest and mixed pine forest occur in the floodplain south of Smithwood Road which bisects the property from west to east. Livestock have access to the mixed pine forest while the hardwood forest remains mostly fenced. The remaining ' forested communities are narrow strips of trees and shrubs growing along fence lines. The primary species are eastern red cedar (Juniperus virginiana), persimmon (Diospyros virginiana), sweetgum (Liquidambar styraciflua), and Chinese privet (Ligustrum sinense). Pasture land dominates the Site and is characterized by native grasses with various invasive ' species such as pig weed (Chenopodium album), cocklebur (Xanthium strumarium), and ragweed (Ambrosia artemisiifolia). Patches of shrubby species occur adjacent to the streams ' and tributaries; however, these species have been bush hogged (mowed) or manually cleared. Shrubby species include blackberry, multiflora rose, black willow (Salixnigra), red maple (Acer rubrum), and sweetgum. Multiple wetland depressional areas support a wet herbaceous assemblage dominated by rushes and sedges (Juncus and Carex spp.). Reforestation of hardwood species may be achievable within the entire on-site floodplain complex. Forest species are expected to vary from bottomland hardwood forest to a more mesic levee mixed forest based on topographic variations. Species composition should mimic ' reference forest measurements of similar undisturbed floodplains in the region. An ecological approach to restoration is expected within the Site; therefore, a varied forest structure should ,' target habitat diversity. . 2.3 STREAM CHARACTERIZATION On-site streams have been characterization based on fluvial geomorphic principles (Rosgen 1996). Table 1 provides a summary of measured stream geometry attributes under existing conditions (considered to be unstable) and a preliminary estimate of potentially stable stream attributes. Establishment of specific design channel attributes will require measurement of a reference (relatively undisturbed and stable) stream reach within the hydrophysiographic ' region. Preliminary estimates of stable stream attributes are based primarily upon data observations along the existing reaches, regional curves (Harman et. al. 1999), and stream gauge data collected in stream gauges in the vicinity of the Site. 1 a r L? U TABLE 1 STREAM GEOMETRY ATTRIBUTES CAUSEY FARM MITIGATION SITE S. S Sin Substrate Stream Type aV9 BHR wbk11, o (riffle) (riselrun) (riselrun) Reach Ai (mi) = Ift) (ft) wdt•depth (ft2) (ft21 Existing Stream Attributes, North Prong Stinking Quarter Creek, Pie dmont Physiographic Province 0023 1 3 Average 23.3 2.4 278 323 114 57.4 1.0 11 66.1 55 0018 . . 86 38-93 - 5-17 61.9-70.3 38.72 --°--• -----•- Sand and Silt E1C 9 6-32 13 1.9-2.8 228.342 277.369 76-1 Range 5.8 . . .--_-- Average X1S. 1.3 -•- _ Average XlWbkn ' ?- ?- 13 15.2 5.4 2.7 --- --- Range XIS. 11 16 13-17.3 3.6-8J L8 4.4 - .- Range Xlwbkn "-•---- l Curves i R ona eg Stable Attributes based on 0018 0023 1.3 Average 26 2.5 278 323 260 130 1.0 9 66.1 ------ 312 104-156 ------ 8-10 1,9-70.3 6 --- •-° ----._ ------ - Sand and l G E ------ 228.342 277.369 182- rave Range 5.8 ------- ---- Average XISwa 1.3 _•....- Average X1Wbkn ------- 11 12.4 10 5 •---_- --- ------- :j -•--- Range XIS, ------ 8.7-13.2 10.6-14.1 7-12 4-6 ----- - Range Xlw,ko ------ A A M .I S. S"a ' Sin Substrate Stream Type Wbkn D.9 wb i w?, L.. ? BHR wbknlDwg (riffle) (riffle) (rise/run) (rise/run) Reach (n (riff le) (riff le) e t (ft) (ft) (ft) Ift) bankheiphtrato width-depth rato (ft2) (ft2) (ft) (ft) Existing Stream Attributes, Unnamed Tributary, Piedmont Physiographic Province 006 1.1 1 2 8 20.9 40 0055 . Average 12 1.5 42 89 etitive re ti t di N . p nc , s o ---••-• •°--•- Sand and 7 3 1 1 38-112 80117 pattern of riffles and 1.0-1.5 5-12 20-21.4 12.8-88 ----- - Silt E -D E1G Range 7.6-15.1 . . pools due to ditching S 1,0 . Average X1 ------- 3 5 8.3 and straightening ----•- Average Xlwbkn °""' . activities --- Range XIS„„ V11 "-"" ------ 3.2-9.3 6.7-10 ---- ? Range X/ l Curves i R ona eg Stable Attributes based on 009 006 1.5 99 134 67 1.0 9 20.9 •---••- . Average 13.4 1.6 200 60 54-80 ------- 8.10 20-21.4 ------ •--•••- ---•••- Sand l and E 6 1-13 13 1.5-1.6 134-268 80-117 941 Grave Range 1.0 . . ------ Average XIS,, Average Xlwbkn -""" .--._- 15 7.4 10 5 •------ - . Range XIS„„ Range XMbe, 10-20 6.8.7 7-12 4-6 --• J J 11 11 ' 2.3.1 Stream Classification Stream geometry and substrate data have been evaluated to orient stream restoration based on a classification, utilizing fluvial geomorphic principles (Rosgen 1996). This classification stratifies streams into comparable groups based on pattern, dimension, profile, and substrate characteristics. Primary components of the classification include degree of entrenchment, width/depth ratio, sinuosity, channel slope, and stream substrate composition. Stream. classes associated with the Site include E, C, and G. Each stream type is modified by a number from one through six (example: C5) denoting a stream type which indicates a ' substrate dominated by 1) bedrock, 2) boulders; 3) cobble, 4) gravel, 5) sand, or 6) silt/clay. ' Historically, on-site reaches may have been characterized as E4-type streams. E-type streams are characterized as slightly entrenched, riffle-pool channels exhibiting high sinuosity (> 1.5). ' In North Carolina, E-type streams often occur in narrow to wide valleys with well- developed alluvial floodplains (Valley Type VIII). E-type streams typically exhibit a sequence of riffles and pools associated with a sinuous flow pattern. E-type channels are typically considered stable. However, these streams are sensitive to disturbance and may rapidly convert to other stream types. Clearing of riparian vegetation, ditching and straightening activities, and hoof shear from livestock entering the channels, have resulted in bank collapse and erosion of on-site reaches. A majority of the on-site reaches are currently characterized as unstable, E/C- and E/G -type channels which are systematically entrenching (G-type) and widening (F-type) due primarily to the lack of deep rooted riparian vegetation. Bank materials are expected to continue to erode until a stable floodplain has been scoured at the current elevation of the disturbed streams. A majority of the unnamed tributary reach appears to have been dredged, straightened, and impacted by land clearing and livestock grazing. Grazing of livestock near stable streams (E stream-type) typically leads to channel adjustments including increases in bank erosion, width/depth ratio, stream gradient, and sediment supply. In addition, these impacts may lead to decreases in channel sinuosity, meander width ratio, and sediment transport capacity (Rosgen 1996). Straightening of channels induces erosion of bed and bank materials, which exasperates sediment transport problems. The unnamed tributary is expected to continue to erode and deposit sediment into receiving streams until a stable stream pattern has been carved from the adjacent floodplain. r 2.3.2 Dimension Regional curves (Harman et.. a/. 1999) and field indicators of bankfull were utilized to determine bankfull channel cross-sectional area in on-site reaches. The cross-sectional areas 1 10 I? L? u I C? I 1 11 ' were then utilized to determine the bankfull width, average bankfull depth, maximum depth, and floodprone area of existing on-site channels. Using this method, a departure from ' stability could be estimated based on a comparison of existing and proposed (stable) dimension variables. Based on preliminary information, regional curves appear to overestimate the stable channel cross-sectional area at the Site. The existing North Prong Stinking Quarter Creek is characterized by a downstream cross-sectional area of approximately 38 square feet. This reach of the creek is classified as an E-type channel with a bank-height-ratio of 1.0. The channel does not exhibit excessive bank collapse and appears relatively stable. Regional curves indicate that a cross-sectional area of greater than 70 square feet is expected to occur in this reach. Regional curve comparisons to on-site cross-sectional data prompted a search of nearby stream gauges to verify the accuracy of regional curve predictions of bankfull discharge at. ' the gauged site. Three gauged streams were identified which appear to represent similar drainage basin characteristics to the Site (Reedy Fork near Oak' Ridge, Rocky River at SR ' 1300, and Cane Creek Near Orange Grove). A peak annual discharge with a return interval of 1.3 years has been utilized to predict bankfull discharge for this study. ' Regional curves predicted a 1.7 year return interval at two of the three gauges, indicating that regional curves may slightly overestimate bankfull discharge and bankfull cross-sectional area at the Site (gauge data is included in Appendix A). This information suggests that measurement of a nearby reference (relatively undisturbed) reach is imperative for the development of dimension variables to be constructed at the Site. However, for the purposes ' of this preliminary study, the regional curves have been utilized to predict stable channel dimension variables (Table 1). Based on regional curve estimations of cross-sectional area, it appears that various stream bank erosional scenarios occur on-site. The majority of the Site is characterized by channel incision which results in bank-height-ratios ranging from 1.0 to 1.5 (low bank height / bankfull height). The down-cut may have resulted from a lack of adjacent deep-rooted riparian vegetation. The down-cut has resulted in an incised channel that has begun to actively erode channel banks below the effective rooting depth of existing riparian vegetation. ' These channels are expected to widen, causing the stream type to migrate towards an F-type (widened gully) or disturbed C-type stream. However, until an active floodplain has been carved, the channel is expected to remain an unstable, narrow and deep, E/G-type channel. 11 Based on this assessment, measures designed to reduce the bank height ratio and widen the active floodplain are recommended along the channel. 2.3.3 Profile _ Based on USGS quadrangles, the on-site valley slope measures approximately 0.0023 rise / run for North Prong Stinking Quarter Creek and 0.006 rise / run for the unnamed tributary. Estimated valley slopes appear typical for the Piedmont physiographic region of North Carlina. Water surface slopes were estimated by dividing the valley slope by channel sinuosity. Sinuosity was inferred from aerial photography and /or Global Positioning System technology. Sinuosity for North Prong Stinking Quarter Creek and its unnamed tributary were measured ' at 1.3• and 1.1, respectively. Calculated water surface slopes (Tables 1), range, from approximately 0.0018 rise/run for North Prong Stinking Quarter Creek and 0.0055 rise / run for the unnamed tributary. Dredging and straightening of the unnamed tributary appears to have resulted in' an over ' steepened water surface-profile. Currently the water surface profile is approximately equal to the valley surface slope; 0.0055 versus 0.006 (Table 1). In addition, channel ' modifications have obliterated the riffle-pool morphology characteristics of stable streams in the region. Existing riffle slopes and pool slopes are, on, average, outside the range of acceptable values considered for E-type streams in the region. An over steepened water surface slope may be detrimental to on-site channels due to increased erosive forces, altered secondary flow cells, and energy dissipation, possibly ' resulting in a step-pool channel morphology. Measures designed to reduce water surface slope and restore riffle-and pool-slopes to suitable ranges is expected to be targeted ' throughout the unnamed tributary. ' 2.3.4 Plan Form Aerial photography and in-field surveys were utilized to determine existing on-site plan form variables. Once the existing plan form variables were identified, they were compared to ratios of stable plan form variables based on fluvial geomorphic methods (Rosgen 1996). Using this method, a departure from stability could then be estimated. On-site channels support sinuosi ties ranging from between 1.1 to 1,3 (thalweg distance / valley distance). The unnamed tributary sinuosity (1.1) is considered low (based on geomorphic priciples) and North Prong Stinking Quarter Creek is considered moderate (1:3). Stable sinuosities for E-type streams are expected to measure approximately 1.5. Reduced sinuosities may result from bank collapse, channel obliteration, and dredging and straightening ' of channels. The unnamed tributary exhibits a belt width that ranges from 38 to 112 feet 1 12 11 1 1 11 n ' which is well below the expected range of 134 to 268 feet. The North Prong Stinking Quarter Creek belt width ranges from 228 to 342 feet and appears to represent stable pattern characteristics (based on regional curve estimates and reference ratios). On-site meander wavelengths average approximately 114 feet on the North Prong Stinking Quarter Creek but no distinct, repetitive pattern of sinuous riffle and / or pools were identifiable in the unnamed tributary due to straightening activities. A stable maximum wavelength for the unnamed tributary is expected to range between 94 to 160 feet with pool-to-pool spacings of approximately 54 to 80 feet (Table 1). Based on plan form variables, on-site channels include reaches that have been dredged and ' straightened or have been degraded by bank collapse and channel obliteration, thereby reducing the beltwidth, meander length, and sinuosity of the reach. Mitigation efforts targeting increases in sinuosity, beltwidth, and meander wavelength will be investigated along ' degraded sections to establish parameters within the range of potentially stable values for these attributes. 2.4 WETLANDS ' Jurisdictional wetlands are defined by the presence of three criteria: hydrophytic vegetation, hydric soils, and evidence of wetland hydrology during the growing season (DOA 1987). . Portions of the Site historically supporting jurisdictional wetlands may have been characterized by palustrine, forested wetlands and groundwater seeps which were seasonally flooded. These wetland areas have been impacted by ditching, capping of spring heads, livestock trampling, deforestation, and groundwater draw-down from stream channel downcutting. Currently, on-site wetlands are characterized by a monoculture of sedges and rushes which i are subjected to livestock trampling and heavy grazing pressure. Jurisdictional wetlands are underlain by alluvial soils of the Wehadkee series which occur in a large patch-like network throughout the on-site floodplains (Figure 5). Significant areas of jurisdictional wetlands ' occur adjacent to both the unnamed tributary and North Prong Stinking Quarter Creek. ' Based on aerial photography and on-site investigations, approximately 21 acres of the floodplain currently are underlain by hydric soils that may have at one time supported jurisdictional wetlands. Down-cutting of stream channels and ditching of spring heads may have effectively lowered the adjacent groundwater table and soil saturation to below jurisdictional thresholds. In addition, livestock trampling and regular maintenance of agricultural fields have disturbed the natural state of these sensitive areas. Removal of livestock and planting with native forested vegetation may allow the floodplain to preform wetland functions such as flood-flow suppression, nutrient cycling, pollutant removal, and ' provide habitat for native species. 13 7 1 C! t r ..F,?r?°A^ MP,'n t ,,"?$r.- "u? ,mss h ry ?• s r 2 W !: k._ BEAVER IMPOUNDMENT PROJECT BOUNDARY S y 1Y { 491, 4" P'K`v? d r.* ur 71 t t I fi' 4MS^ 1!Ap ya. IC vg'? k `r ? y?4 ?'S 7: t t 4; ? a? "r v f 300 ft. 0 600 ft. ,'rS x y 4 > _ a I 'f r 17200 s7 ;Ll x?x .. ?, ?t` p '' d 1 #Pr?f?p:Po Y?6'r ti' a s !%n -i EcoScience Corporation Raleigh, North Carolina 27605 Client: Project: CAUSEYFARMS MITIGATION SITE GUILFORD COUNTY, NORTH CAROLINA Title: HYDRIC SOILS 'd ?Y6P v1°w` ' Dwn By Date: S f Ft MAF FEB2002 Ckd By. Scale: WGL AS Shown ESC Project No.: 98-029 FIGURE 5 I 1 I ' 3_0 CONCEPTUAL MITIGATION PLAN The primary goals of this mitigation plan include: 1.) construction of a stable, riffle-pool stream ' channel; 2) enhancement of the water quality functions in the on-site, upstream, and downstream segments of North Prong Stinking Quarter Creek and its associated unnamed tributaries; 3) creation of a natural vegetation buffer along on-site stream channels; 4) ' restoration of wildlife habitat associated with a riparian corridor / stable stream; and 5) restoration of jurisdictional wetland hydrology to the floodplain of North Prong Stinking Quarter Creek and the unnamed tributary. Primary activities designed to restore the stream and wetland complex include: 1) stream ' restoration; 2) stream enhancement; 3) wetland restoration; and 4) vegetative community restoration (Figure 6). The mitigation concept outlined in Figure 6 is expected to restore ' approximately 6840 linear feet of stream and 5 to 7 acres of jurisdictional wetland, along with the subsequent enhancement of 3180 linear feet of stream and 14 to 16 acres of ' jurisdictional wetland. 3.1 STREAM RESTORATION ' Alternatives for stream restoration are designed to provide a stable stream channel and in- stream aquatic habitat while protecting the adjacent stream banks from extensive erosion. The alternatives proposed for this project are based primarily on professional judgement and potentially stable stream attributes characteristic of the region. ' The majority of the on-site stream channels are classified as E/G stream types. The cross- sectional area of on-site channels appear to have become unstable due to excessive bank erosion from deforestation, livestock trampling, and channel dredging / straightening. In addition, the bank height ratio of on-site channels, especially in the unnamed tributary, appears to have been elevated from 1.0 (stable stream channel) to between 1 .0 and 1 .5. ' Bank collapse, channel straightening, and erosion also appears to have reduced sinuosity of on-site channels to below the modal concept for stable E-type (highly sinuous) and C-type (moderately sinuous) streams in the region. Stream mitigation options should focus on the reduction of channel cross-sectional area ' (decreasing bank-height-ratio) and increasing sinuosity (reducing water surface slope). Stream mitigation activities which may be utilized to achieve these results include: 1) the construction of a channel on new location throughout most of the unnamed tributary; 2) bank stabilization and installation of grade control structures within secondary tributaries and North Prong Stinking Quarter Creek; and 3) the construction of bankfull benches near the upstream and ' downstream terminus of the Site. These mitigation activities are expected to result in 15 I I I I I I I I I I I I I I I I I I I F f7_ ? M F ? ¢(1s>r r ? ? ? ) u' 6? ?y tr i. ray R i ?, II w`. k?,a Y ;i ? w EcoScrence Corporation Raleigh, North Carolina 27605 Client: Project: CAUSEY FARMS MITIGATION SITE GUILFORD COUNTY, NORTH CAROLINA Title: CONCEPTUAL MITIGATION PLAN R ' a i 4,w Dwn By: Date: MAF FEB 2002 ` 4 soh Ckd By. Scale: >?p WGL As Shown ESC Project No.: 98-029 FIGURE 6 I I I I I I I I I I I I I I I I I I I t approximately 6840 linear feet of stream restoration and 3180 linear feet of stream enhancement (Figure 6). ' 3.1.1 Channel Construction on New Location _ Channel construction on new location is expected to occur predominantly in the unnamed tributary due to limited concerns of hydrologic trespass. Channel construction is expected to entail the preparation of a belt width corridor prior to channel excavation. Belt width ' corridor preparation will entail channel staking and any necessary grading prior to channel excavation. Spoil material excavated during the grading and channel excavation process is expected to be stockpiled adjacent to the existing unnamed tributary channel that will be abandoned and then backfilled. ' Once belt width corridor preparation is complete, the proposed channel will be excavated to the average width, depth, and cross-sectional area derived from reference reach studies and detailed measurements of on-site streams. The stream banks and local belt width area of ' constructed channels will be immediately planted with shrub and herbaceous vegetation. Black willow shrubs may be removed from the banks of the abandoned channel and ' stockpiled during clearing to be replanted in the new stream channel. Root mats may also be selectively removed from adjacent areas and placed as erosion control features on channel banks. Particular attention will be directed toward providing vegetative cover and root growth along t the outer bends of each stream meander. Available root mats or biodegradable, erosion control matting may be embedded into the break-in-slope to promote more rapid development of an overhanging bank. Willow stakes will be collected on-site and inserted through the root ' / erosion mat into the underlying soil. The reconstructed channel and vegetation will be allowed to stabilize for a minimum of four months during the growing season prior to ' diversion of flow. Flow will be diverted incrementally to allow for adaption within the reconstructed channel. ' 3.1.2 Bank Stabilization and the Installation of Grade Control Structures Bank stabilization may be performed along eroding outer bends within existing channel ' reaches of North Prong Stinking Quarter Creek, the hardwood forest section of the unnamed tributary, and two secondary tributaries entering the unnamed tributary from the east (Figure 6). Particular attention should be placed on outer bends of eroding pools or excessively eroding banks. Bank slopes will be protected through placement of appropriate structures such as brush mattresses, live brush layering, matting, rock toe protection, root wads, cross- 1 vanes, and / or J-Hook vanes. 1 17 P I I I I I I I I I I I I I I I I I I I ' Grade control structures may be placed in the channel to elevate local water surface profiles in the channel, potentially flattening the water energy slope or gradient. The structures would likely consist of boulder-size rock vanes or step-pool devices designed primarily to direct stream energy into the center of the channel and away from actively eroding banks. In _ addition, the structures would be placed in relatively straight reaches to provide secondary (perpendicular) flow cells during bankfull events. ' 3.1.3 Bankfull Bench Construction The potential excavation of a bankfull floodplain bench in North Prong Stinking Quarter Creek is expected to: 1) remove the eroding material and collapsing banks; 2) promote overbank ' flooding during bankfull flood events; 3) reduce the erosive potential of flood waters; and 4) increase the width of the active floodplain. After excavation, the bench would provide a ' relatively level floodplain surface which could be stabilized with suitable erosion control measures. Planting of the bench with native floodplain vegetation may reduce erosion of bench sediments, reduce flow velocities in flood waters, filter pollutants, and provide wildlife habitat. ' Floodplain benches may be constructed in North Prong Stinking Quarter Creek and reaches where hydrologic trespass may preclude increased water surface elevation. Stream reaches that may receive floodplain bankfull benches are located at the upper extent of on-site streams, near property boundaries, and at the Site outfall. ' 3.1.4 Ford Removal and Construction Several on-site fords have been identified in both the unnamed tributary and North Prong Stinking Quarter Creek. These existing fords have resulted in impoundment of on-site ' streams and obliteration of stream banks; therefore, removal of the fords is proposed within the Site. Replacement fords may be constructed to allow the passage of cattle and or ' vehicles. The fords are expected to consist of a shallow depression in the stream banks where vehicular crossings can be made. Flexibility in the location of the fords exists and may be changed upon request by landowners or on-site construction managers. The fords shall ' be constructed of hydraulically stable rip-rap or suitable rock and should be large enough to handle the weight of anticipated vehicular traffic. Approach grades to the fords should be approximately 30 feet in length and constructed of hard, weather-resistant crushed rock or other permeable material which is free of fines. The bed elevation should be equal to the bed elevation of the design stream channel above and below the fords to reduce the risk of headcutting. 18 1 P 3.2 WETLAND RESTORATION Alternatives for wetland restoration are designed to restore a fully functioning wetland system ' which will provide surface water storage, nutrient cycling, removal of imported elements and compounds, and will create a variety and abundance of wildlife habitat. Wetland restoration alternatives are based primarily on professional judgement and a reference wetland is ' expected to be measured to determine vegetative features, micro- and macro- topographic variations, and soil structure components to be targeted during development of the Site. Portions of the Site underlain by hydric soil have been impacted by ditching of natural springs, channel incision, vegetative clearing, livestock grazing, and earth movement associated with ' agricultural practices. These areas are characterized by a near mono-culture community of sedges, grasses, and rushes, under severe impact from soil compaction by livestock ' trampling. Wetland mitigation options should focus on the restoration of vegetative communities, elevating groundwater tables to jurisdictional conditions, and the re- establishment of soil structure and micro-topographic variations within the existing floodplain. Restoration of wetland hydrology and wetland soil attributes may involve: 1) excavation and ' grading of elevated spoil and sediment embankments; 2) placement of impervious channel plugs along abandoned reaches; 3) backfilling of entrenched stream reaches; and 4) scarification of pasture soils prior to planting. In addition, the construction of (or provisions ' for) surface water storage depressions (ephemeral pools) also adds an important component of groundwater restoration activities. These mitigation activities are expected to result in the restoration of approximately 5 to 7 acres and enhancement of approximately 14 to 16 acres of jurisdictional wetland at the Site. ' 3.3 VEGETATIVE PLANTING Deep-rooted, riparian vegetation will be restored within the entire floodplain complex of both ' the unnamed tributary and North Prong Stinking Quarter Creek. Planting vegetation on cleared stream banks is proposed to re-establish vegetation community patterns within the stream corridor, associated side slopes, and transition areas. Vegetating the floodplain and stream banks is expected to provide stream bank stability, shade and cool surface waters, filter pollutants from adjacent runoff, and provide habitat for area wildlife. The vegetated stream buffer will extend to a minimum of 50 feet on both sides of the stream. Scarification of floodplain surfaces will be required prior to vegetation planting. ' Variations in vegetative planting may occur based on topographic locations and hydraulic conditions of the soil. Vegetative species composition should mimic reference forest data and ' on-site observations. Species expected for this project may include the following elements. t 19 I r J Shrubs / Trees 1 . Green Ash (Fraxinus pennsylvanica) ' 2. Northern Red Oak (Quercus rubra) 3. American Sycamore (Platanus occidentalis) 4. American Elm (Ulmus americana) 7 5. Ironwood (Carpinus caroliniana) 6. Black Cherry (Prunus serotina) ' 7. Smooth Black Haw (Virburnum prunifolium) 8. Black Gum (Nyssa Sylvatica) ' Stream-S 1. ' 2. 3. 4. 5. ide Assemblage Black Willow (Salix nigra) Box Elder (Acer negundo) Ironwood (Carpinus caroliniana) River Birch (Betula nigra) American Sycamore (Platanus occidentalis) Stream-Side Shrub Assemblage 1. Tag Alder (Alnus 2. Buttonbush (Ceph ' 3. Elderberry (Sambu 4. Arrow-wood Vibu 5. Possumhaw Vibur 6. Bankers Dwarf W 7. Black Willow (Sall Approximately 45 acres of on-sit ' construction. Species distribut detailed mitigation planning pha serrula to ) alanthus occidentalis) cus canadensis) rnum (Viburnum dentatum) num (Viburnum nudum) illow (Salix cotteli) 'x nigra) e floodplain is expected to be re-vegetated during mitigation ion and densities are expected to be determined during the se of the project. 1 20 I I I I E I I I I I I H I I I I I 4_0 MONITORING PLAN Monitoring of Site restoration efforts is expected to be performed until success criteria are fulfilled. A monitoring plan and detailed success criteria are expected to be developed during the detailed mitigation planning phase of the project. However, some guidelines which may be utilized to develop a monitoring strategy and success criteria follow. 4.1 STREAM MONITORING ' Annual fall monitoring may include development of a channel plan view, channel cross- sections on riffles and pools, pebble counts, and a water surface profile of the channel. The data may be presented in graphic and tabular format. Data to be presented is expected to ' include: 1) cross-sectional area; 2) bankfull width; 3) average depth; 4) maximum depth; 5) width / depth ratio; 6) meander wavelength; 7) belt width; 8) water surface slope; 9) sinuosity; and 10) stream substrate composition. The streams should subsequently be classified according to stream geometry and substrate (Rosgen 1996). Significant changes in channel morphology are expected to be tracked and reported by comparing data in each ' successive monitoring year. ' 4.2 STREAM SUCCESS CRITERIA Success criteria for stream restoration may include: 1) successful classification of the reach as a functioning stream system (Rosgen 1996); 2) channel stability indicative of a stable ' stream system; and 3) development of diagnostic biological communities over time. The channel configuration may be measured on an annual basis to track changes in channel geometry, profile, or substrate. These data are expected to be utilized to determine the success in restoring stream channel stability. Specifically, the width / depth ratio should ' remain at or below a value of 14 in each monitoring year. In addition the channel should not become incised relative to the adjacent floodplain. Modifications to the channel should be performed to increase or decrease the sediment transport capacity, or other unstable attributes, as needed. If the stream channel is down-cutting or the channel width is enlarging due to bank erosion, additional bank or slope stabilization methods may be employed. 4.3 WETLAND MONITORING Groundwater gauges are expected to be installed in accordance with specifications in U.S. Corps of Engineers', Installing Monitoring Wells/Piezometers in Wetlands (WRPTechnical Note HY-IA-3.1, August 1993). Monitoring gauges should be set to a predetermined depth of ' approximately 40 inches below the soil surface in order to obtain a more accurate depiction of watertable fluctuations. Hydrological sampling may be performed on-site and' within reference areas throughout the year to compare pre- and post-construction conditions. 21 i 1 u 1 t t ' 4.4 WETLAND SUCCESS CRITERIA Target hydrological characteristics may include a minimum regulatory wetland hydrology criteria based upon reference groundwater modeling. Evaluation of success criteria is expected to be supplemented by groundwater gauge data and comparison between restoration and reference areas. Target hydrological characteristics during years with average rainfall include saturation or ' inundation (free water) within one foot of the soil surface for at least 12.5 percent of the growing season. Upper landscape reaches and hummocks within wetland areas may exhibit surface saturation / inundation between 5 percent and 12.5 percent of the growing season. These 5 to 12.5 percent areas are expected to support hydrophytic vegetation within hydric soils. If wetland parameters are marginal as indicated by vegetation and hydrology monitoring, consultation with U.S. Army Corps of Engineers (COE) personnel will be undertaken to determine jurisdictional extent in these areas. ' 4.5 VEGETATION MONITORING Restoration monitoring procedures for vegetation are expected to'be designed in accordance ' with U.S. Environmental Protection Agency (EPA) guidelines enumerated in (EPA 1990) and (DOA 1994). A general discussion of the restoration monitoring program is provided. ' After planting has been completed in winter or early spring, an initial evaluation may be performed to verify planting methods and to determine initial species composition and ' density. Supplemental planting and additional site modifications are expected to be implemented, if necessary. During the first year, vegetation should receive cursory, visual evaluation on a periodic basis to ascertain the degree of overtopping of planted elements by nuisance species. Subsequently, quantitative sampling of vegetation should be performed between September 1 and October 30 after each growing season until the vegetation success criterion is ' achieved. During quantitative vegetation sampling in early fall of the first year, sample plots may be randomly placed within the Site. In each sample plot, vegetation parameters to be monitored may include species composition and species density. Visual observations of the percent cover of shrub and herbaceous species are expected to be recorded. 1 22 1 1 J ' 4.6 VEGETATION SUCCESS CRITERIA Success criteria have been established to verify that the vegetation component supports community elements necessary for floodplain forest development. Success criteria may be ' dependent upon the density and growth of characteristic forest species. ' Guidelines including survivorship of approximately 320 stems per acre in the first three monitoring years may be utilized. Subsequently, 290 character tree species per acre may be ' surviving in year 4, and 260 tree species per acre in year 5. Planted species should represent a minimum of 30 percent of the required stem per acre total (96 stems/acre). Each naturally recruited character species may represent up to 10 percent of the required stem per acre total. In essence, seven naturally recruited character species may represent a maximum of 70 percent of the required stem / acre total. Additional stems of naturally recruited species above the 10 percent - 70 percent thresholds are discarded from the statistical analysis. If vegetation success criteria are not achieved based on average density calculations from ' combined plots over the entire restoration area, supplemental planting may be performed with tree species approved by regulatory agencies. Supplemental planting may be performed as ' needed until achievement of vegetation success criteria. No quantitative sampling requirements are proposed for herb assemblages as part of the vegetation success criteria. Development of floodplain forests over several decades are expected to dictate the success in migration and establishment of desired understory and groundcover populations. Visual estimates of the percent cover of herbaceous species and i photographic evidence may be reported for information purposes. 4.7 CONTINGENCY In the event that vegetation, hydrology, and / or stream success criteria are not fulfilled, a mechanism for contingency may be implemented. For vegetation contingency, replanting and extended monitoring periods will be implemented if community restoration does not fulfill minimum species density and distribution requirements. Stream reconstruction failure may occur due to increased sediment and discharge during development within the upper watershed. Stream contingency will likely include identification ' and modification of upstream sediment sources, additional stabilization of stream banks, and re-establishment of stream substrates required to support target aquatic communities. Recommendations for stream contingency will also be solicited, implemented, and monitored until the Stream Success Criteria are achieved. 23 I 1 ' Wetland hydrology failure may occur due to insufficient hydrologic flow and or unpredictable hydraulic conductivities of disturbed soils. Wetland contingency may likely include modifications of floodplain and or subsurface soils required to support target hydrologic ' regimes. ' Recommendations for vegetation, stream, and wetland contingency is expected to be solicited, implemented, and monitored until the Success Criteria are achieved. 5.0 DISPENSATION OF PROPERTY Restoration Systems will maintain the conservation easement within the Site until all mitigation activities are completed and the mitigation site has been deemed successful. Once the Site has been developed, the easement may be deeded to a land trust organization or community entity suitable to the regulatory agencies. A likely candidate for perpetual maintenance of the easement is Guilford County. The Site may be incorporated into the Guilford County Division Parks and Recreation for use in environmental education and / or ' open space. The current landowner (Mr. Trager) is expected to retain ownership of the properties. The ' conservation easement is expected to be transferred perpetually with the properties upon sale or development of the property. Covenants and / or restrictions on the deed will be included that will ensure adequate management and protection of the Site in perpetuity. 24 I I I I I I I I I I I F I I I I I I I ' 6.0 REFERENCES Department of the Army (DOA). 1987. Corps of Engineers Wetlands Delineation Manual. Tech. Rpt. Y-87-1, Waterways Experiment Station, COE, Vicksburg, MS. Department of the Army (DOA). 1994. Corps of Engineers Wilmington District. Compensatory Hardwood Mitigation Guidelines (12/8/93). Environmental Protection Agency (EPA). 1990. Mitigation Site Type Classification (MiST). EPA Workshop, August 13-15, 1989. EPA Region IV and Hardwood Research Cooperative, NCSU, Raleigh, North Carolina. Harman, W.A., G.D. Jennings, J.M. Patterson, D.R. Clinton, L.A. O'Hara, A. Jessup, R. ' Everhart. 1999. Bankfull Hydraulic Geometry Relationships for North Carolina Streams. N.C. State University, Raleigh, North Carolina. ' Natural Resource Conservation Service (NRCS). 1977. Soil Survey of Guilford County, North Carolina. U.S. Department of Agriculture. Rosgen, D. 1996. Applied River Morphology. Wildland Hydrology (Publisher). Pagosa Springs, Colorado. Rosgen, D. 1996b. "Classification of Natural Rivers: Reply to the comments by J.R. Miller ' and J.B. Ritter." Catena. 27:301-307 t 25 ? t t 1 APPENDIX A STREAM GAUGE DATA ?J t t ' Peak Streamflow Reedy Fork Near Oak Ridge, NC USGS Station #02093800 Drainage Area 20.6 square miles Water Discharge Exceedance Exceedance Year (cfs) Probability Probability % eturn Interval (years) ' 1 1960 3950 0.02 2 46.0 2 1972 2990 0.04 4 23.0 3 1979 2880 0.07 7 15.3 4 1978 2350 0.09 9 11.5 5 1996 2330 0.11 11 9.2 ' 6 1984 2090 0.13 13 7.7 7 2000 2050 0.15 15 6.6 8 1997 1880 0.17 - 17 5.8 9 1993 1590 0.20 20 5.1 10 1969 1500 0.22 22 4.6 ' 11 1959 1460 0.24 24 4.2 12 1991 1440 0.26 26 3.8 13 1989 1310 0.28 28 3.5 14 1973 1250 0.30 30 3.3 15 1987 1250 0.33 33 3.1 ' 16 1965 1210 0.35 35 2.9 17 1977 1210 0.37 37 2.7 18 1975 1040 0.39 39 2.6 19 20 1982 1986 995 965 0.41 0.43 41 43 2.4 2.3 ' 21 1963 960 0.46 46 2.2 22 1974 957 0.48 48 2.1 23 1990 962 0.50 60 2.0 24 25 1992 1970 864 858 0.52 0.54 52 54 1.9 1.8 ' 26 1994 - 837 MMM 0.57 57 1.8 M 28 9905 E 1962 MI 756 0.61 61 1.6 29 30 1956 1998 746 741 0.63 0.65 63 65 1.6 1.5 31 1971 729 0.67 67 1.5 32 1957 719 0.70 70 1.4 33 1980 670 -0.72 72 1.4 34 1966 664 0.74 74 1.4 35 1983 664 0.76 76• 1.3 r3 37 n 1995 w' 582 0.80 80 1.2 38 1981 517 0.83 83 1.2 39 1999 412 0.85 85 1.2 40 1961 408 0.87 87 1.2 ' 41 1964 388 0.89 89 1.1 42 1976 379 0.91 91 1.1 43 1985 378 0.93 93 1.1 44 1968 148 0.96 96 1.0 ' 45 1967 147 0.98 98 1.0 "Jk '?Gby tj? vvJ alv? k C ?,?Prv1 A C cl 1 11 Peak StreamfloW Rocky River at SR1300 Near Crutchfield Crossroads, NC USGS Station #0210166029 Drainage Area 7.4 square miles Return Water Discharge Exceedance Exceedance Interval Year (cfs) Probability Probability % (years) 1 1998 864 0.08 8 12.0 2 1995 698 0.17 17 6.0 ' 3 1997 673 0.25 25 4.0 4 1991 469 0.33 33 3.0 5 1994 429 0.42 42 2.4 6 1999 427 0 50 2.0 7 1989 395 0.58 58 1.7 Gz ,? V 8 1993 340 0.67 67 1.5 ' 9 1990 256 0.75 75 1.3 Lkvi k i 10 1 2 238 0.83 83 1.2 11 2000 201 0.92 92 1.1wwi I 1 Peak Streamflow Cane Creek Near Orange Grove, NC USGS Station #02096846 Drainage Area 7.5 square miles Return Water Discharge Exceedance Exceedance Interval Year (cfs) Probability Probability % (years) ' 1 1996 2060 0.08 8 13.0 2 1993 1740 0.15 15 6.5 ' 3 4 1995 1998 1280 1110 0.23 0.31 23 31 4.3 3.3 5 2000 903 0.38 38 2.6 6 7 1989 1994 864 725 0.46 0.54 46 54 2.2 1.9 8 1999 689 0.62 62 1.6 C?? 9 10 1991 1997 516 458 0.69 0.77 69 1.4 1.3 e? '"ti 1992 433 0.85 85 1.2 12 1990 421 0.92 92 1.1 3 1 61MA K 1 1 I' ¦ • ¦ APPENDIX B ON-SITE CROSS-SECTIONAL DATA I t t t_ ?z V U cn O ? ? S A cn V 0 N O J M 11 N ` 11 N M 11 11 n O LO ?- LO N LO M LO ,I- LO LO C) IN co q1t LO co O M N O N L 'r f y,.. + 1 I i I k, , , ?£ ? I rF Y 1 k ? i X y w ' l 1 V Y 1 I { I I I' y ? 5 f 4 l r ?. '. I, ? ti .K d I y? ? fry , i u S' f t ? ` ? :? m: 4 rr I 1 ?4 F _ ? 6i ? ? a I e I ? ? I 1 5. ?' '? J i5 ty ? .F ?' -.! :1 r f ` 1 e X, ti II + 1 ? 4 s 1 'c f et ?? I v ? iE K + s I P ?? Spd t: S h'K11'tr11 ??-? i'I ?+ kr X14 T a _.. 1 r ? I+ r I ?J ??' 1 DlA ? ?t d y? 1 I a I 'S 1' 1 3 I I 'I Il Ir`l ?M 4 ? ? l 4 ? y ` f l 1 +? IH 1 1 ? 1 '.?: b? f ly I S'RSR'????,, `` 11II y f t ?? 1 t f ? f t ? fY _ I II ? ? I? 1 3 ( 1 ?} I I r v)( ll ? S ? ? II III I1 S r I ? II ? 1 h L , ? I I i t I fk ; r i t ; 1 A 1 ? r f r u, ; xF I i ? , y.g, l i t r '^ } i 1-, ? l h -I, ? i I 1 J A lJ F ? ?' .ir I ;`. 41 ti r?l w rtl f v 7 I I i t $t ' ? 1 1 + I { 1 j I M r? ?• M' C.y `CA: 3 t ll S Q 3 r f o , J;J l-, P ? ......... s a 4 ? r _x I I P 7' ? - ?? ?? t ? ? 1 1 2.? 7 { 1 Y?q 1 1 111 F f I +? S O P K? ? f 1 y ?C? 41 L: s? LO -1-1,41 re) r ? ?? 1 { Fl ? 1 LO - c L ? I -s , S 1 i a 9 Y 7 1 1 t 1 u y t M-?1'% ? ??? U 1 ? I I 1 ( } 1 V tI 5 +ul O ?T ? f ? M ? r N ? _ f _ ?' Y ? ? II I I I 4 ? f t , yf 11 11 1( I y S'3 Z : 4 4 t ? r _ 7 _ 7-7-77 } M8 S w as 7 t 7 e _ l r F ?,` j' ? "Ift It O U') LO N LCD CO LO mot' LC) L" a A ' ' . ' o o O - c T a A 3 N t t t ?m ?a r ?l? • f _ t ?, a J y ? f?? ? t h s }- - s ? sr ?S r XS i ) 9 ? i?? ? ( (b. 1? 1 { 3 ?7r t?.i k.S 2 ?} ? 7 1 J 3 .,' 4 3 ) k,S ?` % , 5 I L t. ? t F l 7? I .tea r ? fi ? ?? F? t I s ? 1 {S?? n. ? i l? 1 1 ., Sl i J f k t J ?r f? p ! I F I .?r Vii) !-y?t + Fw } °Y? r ',fit r8'IS '*x ? J' t t t ? "tii s _ ? r 1'. f _ 1% Z WplS V r?;jt e `'` L t x ?' I a J I ? ?r r?i ? ? j ? If -, 4 (5 c t tij'=? F y, Y {''i i f t \ ? } 1? ? 5 - { YI \ tit _ F B I ? i _ ?! L a )i f 1 ?fi? ? r I r 1 r ?? ?'? r _ t C a *j J ,? fl Z Q J M It CO a O I CY) t T ? ? ? - f. ? IM F 1 i ? U }_ E T ?i T I t ? '1 I , ild ( I ' l Si /? ??/ I I 4. s r ` + ? ? t t f Yj N ?+ f i E ! 1 h r? , t ' r i4'A `? c I I I 1 i f S '? ? i I 7 J Y ? ? 1 I i E ? 2? { Y L. O J 4 1 t - j ? L* O _ ti 1 _ v ? I t f k L I _ I f?( ?JAJ l ` t ? fir r t l 1 Y t s f}; d t{ ? _? ? }I r ?) ? T ,?? A ?I) E t I .; ?? l 1 n 1 i i I O l .Y?'i. V K ? I ?I t t ?.,y ?Ifl ? 1 l? I d 1 J +, ., fl 4 ? Y L r T f r J ) i I! f , t 4 .? >- s f i r ? fir l ? i Fl If I Ts t O (D LO r- LO N U-) In Lo d' £ O r- N co d' 'A 0 ?m u J d u 1 0 fl E Baker and Associates A Unit of Michael Baker Corporation 200 CentrePort Drive, Suite 225 Greensboro, NC 27409 (336) 931-1500 FAX (336) 931-1501 October 30, 2003 Mr. Todd St. John North Carolina Department of Environmental and Natural Resources Division of Water Quality - Wetlands Unit 2321 Crabtree Boulevard Raleigh, NC 27604-2260 Subject: FedEx Development Program Stormwater Management Review Dear Mr. St. John: WETLANDS / 401 GROUP OCT 3 1 2003 WATER QUALITY SECTION Per your request, we are providing additional information for the subject effort. We have enclosed the following: ¦ Drawing depicting the stormwater ponds, associated water quality BMP's, and the surrounding natural terrain ¦ Signed/notarized maintenance agreement for the proposed ponds ¦ Surface Area Drainage Area (SADA) calculations for each system ¦ Detail of Baffle tie-ins ¦ Revised detail (typical section) of flow spreaders The proposed system is a modification of the standard BMP manual, as it includes the use of natural and restored wetlands, as well as a modified dry pond that will function like a non-marsh wetland. The proposed system is meant to function like an extended detention wetland. It includes similar design features, such as a 2-5 day detention of the runoff from a 1-inch rain. It provides more surface area than would be required for an extended detension wetland, without the marsh-type characteristics that could endanger aircraft. As we have discussed, during construction, these ponds will function in an E&S role. They will only truly begin to function as stormwater management ponds upon completion of the proposed FedEx development, which is scheduled to occur in the 2008-2009 timeframe. In response to specific issues discussed, we offer the following solutions for the final stormwater management plan: 1.) Flow Spreaders have been reconfigured per our discussion. These will be further lengthened in the field, if such modification is approved by USAGE. 2.) Pond F2 Emergency Spillway has been relocated per our discussion. 3.) The bottom of the pond will be graded per your suggestion, with small recesses to form ephemeral ponds. The area will be graded, ripped and topsoiled with stockpiled material to encourage vegetative growth. Specifically, per your suggestion, we propose that approximately 50% of the basin will have small depressions not larger than 20' x 20', and average depth of 3-6 inches. Additional small pools not larger than 10' x 10' and average depth of 3 feet will be provide on approximately 100 foot centers to encourage mosquito control species. The entire basin floor of the ponds will be planted with herbaceous and shrubby vegetation as approved by DWQ. Approximately 20%0 of the basin floors will be planted with shrubby wet tolerant vegetation to discourage unwanted wildlife on 3-5 foot centers depending on plant size. MACTEC has provided a suggested planting list that is included with this submittal. 4.) If permitted by the USACE, logs will be placed near the toe of the embankments, and in the natural wetlands to assist with dispersion of higher flows. 5.) Sides of the ponds incorporate 2:1 slopes as recommended by FAA to deter wildlife. The system will use a combination of dry ponds modified per item three, level spreaders, natural buffer area, and natural wetlands to achieve water quality standards. The attached SADA calculations are based upon DENR criteria for Extended Detention Wetlands, and show that more than adequate area is available. Please feel free to call me at 336/931-1500 with any questions. Sincerely, BAKER AND ASSOCIATES evin J. Baker, P.E. Assistant Vice President Enclosures cc: Cindi Karoli, DWQ (w/o Enclosure) M. L. Elmore, PTAA (w/o Enclosure) WETLAND-type DETENTION BASIN OPERATION AND MAINTENANCE AGREEMENT The wetland-type detention basin system is defined as the wetland-type detention basin, pretreatment including energy dissipators and flow spreaders. Maintenance activities shall be performed as follows: After every significant runoff producing rainfall event and at least monthly: a. Inspect the detention basin system for sediment accumulation, erosion, trash accumulation, vegetated cover, and general condition. b. Check and clear the orifice of any obstructions such that drawdown of the temporary pool occurs within 2 to 5 days as designed. 2. Repair eroded areas immediately, re-seed as necessary to maintain good vegetative cover, mow vegetative cover on side slopes, and remove trash as needed. 3. Inspect and repair the collection system (i.e. catch basins, piping, swales, riprap, etc.) quarterly to maintain proper functioning. 4. Remove accumulated sediment from the detention basin system semi-annually or when depth is reduced to 75% of the original design depth. Removed sediment shall be disposed of in an appropriate manner and shall be handled in a manner that will not adversely impact water quality (i.e. stockpiling near a detention basin or stream, etc.). The measuring device used to determine the sediment elevation shall be such that it will give an accurate depth reading and not readily penetrate into accumulated sediments. Natural and restored wetlands will be inspected every six months. Corrective action will be taken for any areas of erosion or concentrated flow. Heavy equipment will be used for these repairs only when so approved by NCDENR and USACE. During project construction, and until the site is release by the DLR, the natural wetlands, constructed wetlands, and wetland buffers will be inspected every quarter for signs of erosion and sediment accumulation. Repairs to eroded areas and removal of accumulated sediment shall be conducted as needed. When basins are maintained, basin bottoms will be returned to the grades shown on the as-built plans. The disturbed surface will be ripped if compacted, and re-vegetated. As necessary, the top 0.3 feet of the basin bottom will be stockpiled and re-applied to the disturbed area to achieve final grade, or the disturbed area shall be re-vegetated according to the vegetation planting plan. 5. If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment through the emergency drain shall be minimized to the maximum extent practical. 6. All components of the detention basin system shall be maintained in good working order. 7. Flow spreaders that provide diffuse flow shall be maintained every six months. All accumulated sediment and debris shall be removed from the structure, and a level elevation shall be maintained across the entire flow spreading structure. Any down gradient erosion must be repaired and/or replanted as necessary. Page 1 of 2 acknowledge and agree by my signature below that I am responsible for the performance of the seven maintenance procedures listed above. I agree to notify DWQ of any problems with the system or prior to any changes to the system or responsible party. Print name: MICV4e, L e:tmorz I, SCE ,? , a Notary Public for the State of C 'rUl I Vhi County of 'u , do her9by certify that Vh.Di*` personally appeared before me this day of K)??bet- and acknowledge the due execution of the forgoing wetland-type detention basin maintenance requirements. Witness my hand and official seal, SEAL My commission expires o 93 ? 60 Page 2 of 2 Title: 1 ??'D ?VLo?,th?T Address: 64 15 V?2KYAnt f,.X, IO ?f?f?F.?t?3 ego W401 (.!.14-011 October 30, 2003 Mr. Todd St. John North Carolina Department of Environmental and Natural Resources Division of Water Quality - Wetlands Unit 2321 Crabtree Boulevard Raleigh, NC 27604-2260 Subject: FedEx Development Program Stormwater Management Review Dear Mr. St. John: Baker and Associates A Unit of Michael Baker Corporation 200 CentrePort Drive, Suite 225 Greensboro, NC 27409 (336) 931-1500 FAX (336) 931-1501 WEI fwfts/401 GROUP OCT 31 2003 WATER QUALITysECT ION Per your request, we are providing additional information for the subject effort. We have enclosed the following: ¦ Drawing depicting the stormwater ponds, associated water quality BMP's, and the surrounding natural terrain ¦ Signed/notarized maintenance agreement for the proposed ponds ¦ Surface Area Drainage Area (SADA) calculations for each system ¦ Detail of Baffle tie-ins ¦ Revised detail (typical section) of flow spreaders The proposed system is a modification of the standard BMP manual, as it includes the use of natural and restored wetlands, as well as a modified dry pond that will function like a non-marsh wetland. The proposed system is meant to function like an extended detention wetland. It includes similar design features, such as a 2-5 day detention of the runoff from a 1-inch rain. It provides more surface area than would be required for an extended detention wetland, without the marsh-type characteristics that could endanger aircraft. As we have discussed, during construction, these ponds will function in an E&S role. They will only truly begin to function as stormwater management ponds upon completion of the proposed FedEx development, which is scheduled to occur in the 2008-2009 timeframe. In response to specific issues discussed, we offer the following solutions for the final stormwater management plan: 1.) Flow Spreaders have been reconfigured per our discussion. These will be further lengthened in the field, if such modification is approved by USACE. 2.) Pond F2 Emergency Spillway has been relocated per our discussion. 3.) The bottom of the pond will be graded per your suggestion, with small recesses to form ephemeral ponds. The area will be graded, ripped and topsoiled with stockpiled material to encourage vegetative growth. Specifically, per your suggestion, we propose that approximately 50% of the basin will have small depressions not larger than 20' x 20', and average depth of 3-6 inches. Additional small pools not larger than 10' x 10' and average depth of 3 feet will be provide on approximately 100 foot centers to encourage mosquito control species. The entire basin floor of the ponds will be planted with herbaceous and shrubby vegetation as approved by DWQ. Approximately 20% of the basin floors will be planted with shrubby wet tolerant vegetation to discourage unwanted wildlife on 3-5 foot centers depending on plant size. MACTEC has provided a suggested planting list that is included with this submittal. 4.) If permitted by the USACE, logs will be placed near the toe of the embankments, and in the natural wetlands to assist with dispersion of higher flows. 5.) Sides of the ponds incorporate 2:1 slopes as recommended by FAA to deter wildlife. The system will use a combination of dry ponds modified per item three, level spreaders, natural buffer area, and natural wetlands to achieve water quality standards. The attached SADA calculations are based upon DENR criteria for Extended Detention Wetlands, and show that more than adequate area is available. Please feel free to call me at 336/931-1500 with any questions. Sincerely, BAKER AND ASSOCIATES 4evin J. Baker, P.E. Assistant Vice President Enclosures cc: Cindi Karoli, DWQ (w/o Enclosure) ?--- M. L. Elmore, PTAA (w/o Enclosure) 10/30/2003 THU 13;51 FAX 336 931 1501 Baker and Associates LC : fvt.IF, Engineering and Energy Baker and Associates Fax Transmittal Letter A&Wsmo0fAi &d8alta Cwp abw Baker and Associates 200 CentrePod Drive, Suite 225 Greensboro, NC 27409 (336) 931-1500 OUR TELEFAX NO. IS: (336) 931-1501 jo f 3a ?d - -?0 :'1 Date: To: (Company) f0 'mil - cJ d ?P- - (AttenUon) WL-TW QS Receiving Telecopier No. From: gooliou3 IIMtGiti?- L?f" 1!? TOTAL NUMBER OF PAGES 3 (INCLUDING THIS TRANSMITTAL PAGE) X08 - dz? IF YOU DO NOT RECEIVE THE NUMBER OF PAGES INDICATED, PLEASE CONTACT OUR OFFICE AS SOON AS POSSIBLE. i UAAXM7W#1"7U•81FAXIitAMJ)0C . i.,. ` :: -....•::.:.:,: -.::e:.-ti :,. 10/30/2003 THU 13:51 FAI 336 931 1501 Baker and Associates 4UUI/003 00, 30, 2003 11:42AM PIEDMONT TRIAD AIR DEVELOPMENT No-0347 P. 1 WETLAND-type DETENTION BASIN OPERATION AND MAINTENANCF- AGREEMENT The wetland-type detention basin system Is defined as the wetland-type detention basin, pretreatment including energy dissipators and flow spreaders. Maintenance activities shall be performed as foilows. 1. After every significant runoff producing rainfall event and at least monthly: a. Inspect the detention basin system for sediment accumulation, erosion, trash accumulation, vegetated cover, and general condition- b, Check and clear the orifice of any obstructions such that drawdown of the temporary pool occurs within 2 to 5 days as designed. 2. Repair eroded areas immediately, reseed as necessary to maintain good vegetative cover, mow vegetative cover on side slopes, and remove trash as needed. 3. Inspect and repair the collection system (i.e. catch basins, piping, swales, riprap, etc.) quarterly to maintain proper functioning. 4. Remove accumulated sediment from the detention basin system serni?nnually or when depth is reduced to 7516 of the original design depth. Removed sediment shall be disposed of in an appropriate manner and shall be handled in a manner that will not adversely impact water quality (i.e. stockpiling near a detention basin or stream, etc.). The measuring device used to determine the sediment elevation shall be such that it will give an accurate depth reading and not readily penetrate into accumulated sediments- Natural and restored wetlands will be inspected every six months. Corrective action will be taken for any areas of erosion or concentrated flow. Heavy equipment will be used for these repairs only when so approved by NCDENR and USACE. During project construction, and until the site is release by the DLR, the natural wetlands, constructed wetlands, and wetland buffers will be Inspected every quarter for signs of erosion and sediment accumulation. Repairs to eroded areas and removal of accumulated sediment shall be conducted as needed. When basins are maintained, basin bottoms will be returned to the grades shown on the as-built plans. The disturbed surface will be ripped if compacted, and re vegetated. As necessary, the top 0,3 feet of the basin bottom will be stockpiled and re-applied to the disturbed area to achieve final grade, or the disturbed area shall be re-vegetated according to the vegetation planting plan. 5. If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment through the emergency drain shall be minimized to the maximum extent practical. 8. All components of the detention basin system shall be maintained in good working order. 7, Flow spreaders that provide diffuse Clow shall be maintained every six months. All accumulated sediment and debris shall be removed from the structure, and a level elevation shall be maintained across the entire flow spreading structure- Any down gradient erosion must be repaired and/or replanted as necessary. pw l of 2 10/30/2003 THU 13:51 FAI 336 931 1501 Baker and Associates 4UUS/UUJ Oct-30. 2003 11:42AM PIEDMONT TRIAD AIR DEVELOPMENT No-0347 P. 2 1 acknowledge and agree by my signature below that I am responsible for the performance of the seven maintenance procedures listed above. I agree to notify DWQ of any problems with the system or priorto any changes to the system or responsible party. Print t, 1 + a Notary Public for the State of Q f`t7 I County of ?u 1 do hergby certify that -it personally appeared before me this day of and acknowledge the due execution of the forgoing wetland-type detention basin maintenance requirements. Witness my hand and official seal, SEAL My commission expires Page 2 of 2 Tide: 9 92t Address: ,,,f 15 IYA '?LY acs aka _74Q`i 10/30/2003 THU 11:44 FAI 336 931 1501 Baker and Associates & _ Ik_F,L' ? Engineering and Energy Baker and Associates Fax Transmittal Letter A DMWW of,Wd aal B*src«po/ada? Baker and Associates 200 CentrePort Drive, Suite 225 Greensboro, NC 27409 (336) 931-1500 OUR TELEFAX NO. IS: (336) 931-1501 d Date: 10 N6 1D:> 110 `• To: , (Company) lpri7lD ?LLl -rr J 6 Vj (Attention) Receiving Telecopler No: From: ?t 4001/003 IF YOU DO NOT RECEIVE THE NUMBER OF PAGES INDICATED, PLEASE CONTACT OUR OFFICE AS SOON AS POSSIBLE. ..... L1 AKEFtTOA),LATEWFAXTPANS.DOC •.-- Y:. _.,_........ .. ... ... . . TOTAL NUMBER OF PAGES 3 (INCLUDING THIS TRANSMITTAL PAGE) 10/30/2003 THU 11:45 FAI 336 931 1501 Baker and Associates 1002/003 Oct-30. 2003 11:42AM PIEDMONT TRIAD AIR DEVELOPMENT No-H47 P. 1 WETLAND-type DETENTION BASIN OPERATION AND MAINTENANCE AGREEMENT The wetland-type detention basin system is defined as the wetland-type detention basin, pretreatment Including energy dissipators and flow spreaders. Maintenance activities shall be performed as follows: 1. After every significant runoff producing rainfall event and at least monthly: a. Inspect the detention basin system for sediment accumulation, erosion, trash accumulation, vegetated cover, and general condition. b. Check and clear the orfice of any obstructions such that drawdown of the temporary pool occurs within 2 to 5 days as designed. 2. Repair eroded areas immediately, rem as necessary to maintain good vegetative cover, mow vegetative cover on side slopes, and remove trash as needed. 3. Inspect and repair the collection system (i.e. catch basins, piping, swales, rlprap, etc.) quarterly to maintain proper functioning. 4. Remove accumulated sediment from the detention basin system semi-annually or when depth is reduced to 75% of the original design depth. Removed sediment shall be disposed of in an appropriate manner and shall be handled in a manner that will not adversely impact water quality (i.e. stockpiling near a detention basin or stream, etc.)_ The measuring device used to determine the sediment elevation shall be such that it will give an accurate depth reading and not readily penetrate into accumulated sediments. Natural and restored wetlands will be inspected every six months. Corrective action will be taken for any areas of erosion or concentrated flow. Heavy equipment will be used for these repairs only when so approved by NCDENR and USACE. During project construction, and until the site Is release by the DI-R, the natural wetlands, constructed wetlands, and wetland buffers will be inspected every quarter for signs of erosion and sediment accumulation. Repairs to eroded areas and removal of accumulated sediment shall be conducted as needed. When basins are maintained, basin bottoms will be returned to the grades shown on the ss-built plans. The disturbed surface will be ripped if compacted, and re..vegetated. As necessary, the top 0.3 feet of the basin bottom will be stockpiled and re-applied to the disturbed area to achieve final grade, or the disturbed area shall be re-vegetated according to the vegetation planting plan. 5. If the basin must be drained for an emergency or to perfoan maintenance, the flushing of sediment through the emergency drain shall be minimized to the maximum extent practical. 6. All components of the detention basin system shall be maintained in good working order. 7. Flow spreaders that provide diffuse flow shall be maintained every six months. All accumulated sediment and debris shall be removed from the structure, and a level elevation shall be maintained across the entire flow spreading structure. Any down gradient erosion must be repaired and/or replanted as necessary. Pop l of 2 10/30/2003 THU 11:45 FAI 336 931 1501 Baker and Associates 4003/003 00-30, 2003 11:42AM PIEDMONT TRIAD AIR DEVELOPMENT No-0347 P. 2 I acknowledge and agree by my signature below that I am responsible for the performance of the seven maintenance procedures listed above. I agree to notify DWQ of any problems with the system or prior to any changes to the system or responsible party. j?Ie ati Print name: Title' Krfi it. V'"CE& 19 Address: 15r YA V 090 o A I. !, 1 (E a Notary Public for the State of 1 County of eta 1 do heby certify that personally appeared befor'a me this . ?day of , and acknowledge the due execution of the forgoing wetland-type detention basin maintenance requirements. Witness my hand and official seal, SEAL 1 My commission expires 0 - Page 2 of 2 OCT-31-2003 17:43 CHARLOTTE ENGINEERING DEP P•01 cwtfofte- k*knbwy M STOR 1 -V Ppi S!'IVIGt'S Fax To: ? CA S+- Q 90 - 733- From: ^ 'L `Date: 16 3r'/ 473 lu? Phone: 9 / t V- 1 7- ?p Total # of pages: 11,wco. 5,?C- "p # Ate /e? rgent Rari*w []Please COMMeftf []Please Reply []please Regd& Comment: City of Charlotte Enoneering & Property Management 600 E_ f=ourth Street, Charlotte, NC 28202-2844 704-336-2291 telephone 704-336-6586 fox rr OCT-31-2003 17:43 S"RN NAM s October 31, 2003 CHARLOTTE ENGINEERING DEP NC Division of 'Dater Quality 401 Wetlands Certification Unit Attn: Todd St. John 2321 Crabtree Blvd. Raleigh, NC 27604 Subject: Comment on the September 30, 2003 Request for Comments on joint state and federal stream mitigation guidelines Dear Mr. St. John; P.02 Thank you for repeating the opportunity to review and comment on the draft joint state and Federal stream mitigation guidelines (Guidelines). As indicated in your September 30, 2003 Memo, the Guidelines are intended to provide uniform guidance among the US Army Corps of Engineers, DWQ, EPA, and NC Wildlife Resources Commission with respect to stream mitigation requirements. The following comments on the draft Guidelines are provided on behalf of the City of Charlotte Storm Water Services (CSWS), Charlotte, North Carolina. CSW S commends the agencies, commitment to collaborating on this effort and producing a document that is cohesive and usable. We can appreciate the effort that has gone into developing this document and offer our comments, suggestions, and edits for constructive use. In general our comments are focused on clarifying whether information in the guidance is presented as requirements versus recommendations and making the document more reader-friendly (e.g,, numbering/lettering of sections and sequence of information in Section 11, Monitoring). Our comments are as follows: Table of Contents: Editorial: Update page numbers in Table of Contents to match document. "Appendices"_ • Consider adding the Macroinvertebrate Monitoring Protocol as an Appendix. • Include the following forms in the list under Appendix V o Monitoring Data Record o Site Selection Determination Form (Under Development) o Suggested Reference Channel Data Sheet (Under Development) "1. Introduction°': • At the end of the last sentence of first paragraph, consider adding the language DWQ included in the September 30, 2003 Memo to read "...and supersedes DWQ's stream mitigation guidelines in the .interim, Internal Stream Mitigation and Macroinvertebrate Monitoring Policy, previously adopted on May 10, 2000_" To report drainage problems. 336-RAIN Printed on recycled papar. OCT-31-2003 1?:43 CHARLOTTE ENGINEERING DEP October 31, 2003 Coxunent Letter Yhaft Stream Mitigation Guidelines P.03 Page 2 of 2 • CSW S recommends that the document be modified to allow more project specific flexibility. Attempting to standardize the requirements by categorizing all projects may restrict innovative approaches to restoration practices in urban areas. Mitigation requirements (e.g., siting, design, monitoring) may need to be proj ect specific in some cases such as the Edwards Branch Watershed Improvemexit Project_ The guidance should focus on recommended characteristics to monitor and include the preferred standard or method, to use in performing the monitoring. The emphasis should be on standardizing what specific parameters are monitored and how data should be collected for typical projects that fall within each of the proposed categories. Paragraph 3 and 4 of the Introduction should be modified to clarify that the agencies are providing recommendations and that for certain projects a modified approach may be more appropriate. • Information in this section has been very helpful to CSW S as we are trying to standardize our monitoring protocols and consultant scope of services for our mitigation projects. Additional resources on recommended methodologies for performing the various categories of monitoring would also be beneficial to the regulated community. • The guidance is not very specific in relation to plant survival monitoring. Are there any recommendations for monitoring of plant survival for typical stream restoration projects? Is there a standard total percentage of the site area/stream length that should be surveyed through the plots? Should the plots be selected randomly each year or just randomly during an as-built survey and revisited for subsequent years? • To simplify the presentation of the infornnation and help facilitate quick reference to specific categories, CSWS offers several hand written suggestions for this section as shown on the attachment to this comment letter. See attached. "A endix V Monitorin Data Record", • CSWS recommends adding a data field in Section 2, Plant Survival for sterns/acre and percent survival so that a quick reference to success criteria can be made. Thank you again for the opportunity to review and comment on the draft Guidelines. Again, if you have any questions concerning our comments or would like further detail, please don't hesitate to contact me at 704-336-45$$ or mkmurray r@ci.charlotte_nc.us. Sincerely, ?r 7Ma C.1VI ay Charlotte Storm Water Services Attachment CC' S_ McLendon, US Army Corps of Engineers OCT-31-2003 17:44 CHARLOTTE ENGINEERING DEP xxf 1ItTt(TKl0fJ W%0E?1JV5 Reference: NCDENR Stormwater BMP Manual, April 1999 2000 Maryland Stormwater Design Manual Volumes I & B B. Other Approaches Other actions that result in demonstrable stream improvements may also be eligible for stream mitigation crediting on a case-by-case basis. However, these measures (BMP's or any other activity) must not be a requirement of a NPDES permit or other regulatory requirement. These options would have to be beyond those measures required by regulations and should be part of a local watershed restoration plan. These other options can provide long-term protection for a stream segment or a watershed and therefore have a role in stream mitigation. However, the US Army Corps of Engineers and the NC Division of Water Quality may limit the use of these other options in the context of stream mitigation since these agencies need to ensure that aquatic life uses are being replaced. These options must receive case-by-case approval from the US Army Corps of Engineers and the NC Division of Water Quality and must include a provision for monitoring that will demonstrate the water quality and aquatic life benefits of the project. As such, projects that target waters with impaired water quality such as 303(d) waters, closed SA waters and Nutrient Sensitive Waters are more likely to be approved. 11. MONITORING The purpose of monitoring is to determine the degree of success a mitigation project has achieved in meeting the objectives of providing proper channel function and increased habitat quality. Specific objectives trust be included in a project design and may also be evaluated. In general, monitoring data should provide the District and DWQ with evidence that the goals of the project were met. Monitoring should be directed at evaluating primary activities accomplished through mitigation projects. Monitoring secondary benefits or accomplishments may also be appropriate for large-scale projects, when projects are done in ecologically important areas or when secondary benefits are a primary objective. Secondary benefits are those that are not directly accomplished or established during site construction. For example: a primary activity would be constructing a root wad revetment, the secondary benefit would be the enhancement of OVA aquatic populations' three levels of monitoring will be required based on the complexity roposed. It'` ? AcAA- "y" av?n 'L'am p of the mitigation p;-,, ect being 3 1? -to- C. Upon complet?on o e project, an as-built channel survey sha conduct it is recommended that stream surveys, for both project construction and project monitoring, follow the methodology contained in the USDA Forest Service Manual, Stream Channel Reference Sites (Harrelson, et.al, 1990. The survey should document the dimension, pattern and profile of the restored channel. Permanent cross-sections should be established at an approximate frequency of one per 20 (bankfull-width) lengths. In general, the locations should be selected to represent approximately 50% pools and 50% riffle areas. Flexibility in the location and frequency will be allowed for 22 P.04 ?jogf P, ' 1t'p- Ma boe pool 'Ps ?0 OCT-31-2003 17:44 CHARLOTTE ENGINEERING DEP different levels of mitigation wou require different eve s of monitorin P.05 cross-sections and should be based on best professional judgment. The selection of locations should always include areas that may be predisposed for potential problems. In the case of very narrow streams, two cross-sections per 1,0001f will generally be, sufficient. The as-built survey should also include photo documentation at all cross- sections and structures, a plan view diagram, a longitudinal profile, vegetation information and a pebble count for at least six cross-sections (or all cross sections if less than six required for project). If the restored stream section is less than 3,000 If, the longitudinal profile should include the entire 3,000 If, if the stream section is greater than 3,000 If, the profile should be conducted for either 30 % of the restored stream or 3,0001f (whichever is greater). Subsequent annual surveys will be required Per instructions on 317- d the monitorin forms (biannual for photo documentation). t should be noted that escribe the specific_re uirements for the 0-4 Q6'MCI?.?e C. A3 X Monitvrirrg woos rain j, Monitoring Level )(:'this level of monitoring willfp Iy to Restoration and Enhancement Level I projects. Because these projects involve the greatest degree of complexity they will require a more complex monitoring protocol. The required monitoring shall be performed each year for the 5-year monitoring period and no less than two bankfull flow events must be documented through the monitoring period. If less than two bankfull events occur during the first 5 years, monitoring will continue until the second bankfull event is documented. The bankfull events must occur during separate monitoring years. In the event that the required bankfuli events do not occur during the five-year monitoring period, the Corps and DWQ, in consultation with the resource agencies, may determine that further monitoring is not required. It is suggested that all bankfull occurrences be monitored and reported through the required monitoring period. Monitoring data collected at ipvei I sites should include the following: reference photos, Apr. plant survival analysis, channel stability analysis, and biological data if specifically Bi to ical samplin evaluates second im acts of ?iat1?'S Cse?,,) required?iy permit con ikons ?o g restoration rojects. D pans o eva uate $0 projects across the state to determine the nerits of these data in a mitigation monitoring protocol (see "Interim, Internal 'technical Guide Summary - Benthic IVlacroinvertebrate Monitoring Protocols For Compensatory Stream Restoration Projects, dated July 2002, Version l.3) which is available on DW 's website h ://h 2aenr.state.nc.us/newetlands/. W40r**=Tr10i.- Pic th"6 WARM . Biological data may be required for ethff projects on a case-by-case basi . D e to be collected prior to construction and for at least 3 years following C01116ucW. A I-year recolonization/population adjustment time of biological monitoring following construction is usually warranted. In addition, the yearly data should be collected during the sam onVhoto documentation will be required twice a year - summer and winter. eviations from the required monitoring protocol will generally not be acceptable. However, proposed exceptions will be evaluated on a case-by-case basis by the District and DWQ, and will be coordinated with appropriate permit review agencies- ,2'L f1i Yto ?. 1'llcr?ni o? plank- &AfV1Y4L( ivr fkt riptirun edyvidDY (burger and bd-At" d '1ACIUAesi I.. M6 feffew2* sung?{ 6F 5u" 4 pp 1ot,5) lc c- Counts a.r?d '1ec.. coa?+n - ?¢x c?b?11y Vat se.lecl?ed rond6VAto Co. wwoe.Year-abyea(?) and. r<eptes?? -°? d? '61te. tma. car %Tean "th?). met OCT-31-2003 17:44 CHARLOTTE ENGINEERING DEP J C"-_4 J? I.cu•i s tr 1u.)J11. 1J LAM" tv i-3 j . Monitoring Level 2: This level of monitoring will apply to Enhancement Leve12 projects. Because these projects will generally be on a smaller scale and less complex a simpler protocol is required. Monitoring data at these sites should include the following: reference photos and plant survival. Channel stability should also be evaluated when the mitigation project alters the bankfull channel. Additional types of information may be required from mitigating parties if recommended and justified by project reviewers. Data must be collected each year for 5 years at the same time of year. No less than two bankfulI flow events must be documented through the required 5-year monitoring period. If less than two bankfull events occur during the first 5 years, monitoring will continue until the second bankfull event is documented- The bankfull events must occur during separate monitoring years. It is suggested that all bankfull occurrences be monitored and reported through the required monitoring period. Deviations from this protocol may be acceptable when they can be justified. Monitoring Level 3: This level of monitoring will apply to mitigation consisting only of preservation. Since the only action in this case is administrative, protecting a reach, a 5- year monitoring plan is not required. However, reference photos should be taken and provided to the District and DWQ. These should well document the reach, including the riparian zone being preserved. As for all photo reference sites, a detailed description of the location at which the photo was taken should also be provided. Additional types of information may be required from mitigating parties if recommended and justified by project reviewers. re cDmow& prof f' .Success Criteria: As described above, this guidance r?uee forms of monitoring to evaluate the success of the project; photo documen ion, ecological function, and channel stability measurements. These criteria will be used to evaluate success by considering the following: Photo documentation Channel aggradation or degradation Bank erosion Success of riparian vegetation Effectiveness of erosion control measures Presence or absence of developing instream bars (should be absent) P.06 Ecolo ical Function Health and survival of vegetation (80% survival of planted species required after 5 years) ' AI'?? bt 1(1 restoration reach should mimic upstream conditions (or reference reach when applicable) W00U1N1??1C1. .04 6f l or- 54e Channel Stability I? f ? Should be insignificant change from the as-built dimension arO Ix /!? Do changes represent a movement in the direction of instability (e.g. increased width to weA depth ratio or a decreased width to depth ratio with decreased entrenchment ratio) or are _5(A[W changes minor and represent an increase in stability (e.g. decreased width to depth ratio IF n qd d without a decrease in entrenchment ratio)? to &5CU5196" Should be little change from the as-built longitudinal profile CiAdfr ryw. U(Id S. 24 OCT-31-2003 17:44 CHARLOTTE ENGINEERING DEP Pool/riffle spacing should remain fairly constant pools should not be filling in (aegradation) or riffles starting to change to pools (degradation) Pebble count should show a change in the size of bed material toward a desired composition. Annual monitoring forms require as-built plans and current data. Monitoring reports should contain a discussion of any deviations from as-built and an evaluation of the significance of -these deviations and whether they are indicative of a stabilizing or destabilizing situation. Appendix H summarizes the measures of success, failure, and required remedial actions. P.07 t - IWE frame. Specific biological success criteria are currently a subject of applied research being coordinated by the NC Division of Water Quality. Formal development and adoption of biological success criteria (if any) will be done upon completion of that research. 25 re?,?r+crmend? (u mos. 'Fym VCA- 7) TOTAL P.07 Re: [Fwd: (no subject)] Subject: Re: [Fwd: (no subject)] From: "Kevin Baker" <kjbaker@ mbakercorp.com> Date: Wed, 29 Oct 2003 14:36:45 -0500 To: <todd.st.john@ncmail.net> I'll be here. Give a yell w/any questions. tx "Todd St. John" <todd.st.john@ncmail.net> 10/29/2003 2:34:58 PM got the fax... i've got to leave the office this pm... if the package gets in i'll take a look at it first thing tomorrow... todd Kevin Baker wrote: Todd - Check your fax. course the revised plan Original of the package and Drawing this afternoon. It's on the kevin We're sending the all the info (except, of sheet) via fax for you to review. will arrive in standard FedEx delivery fax as I'm typing. "Todd St. John" <todd.st.john@ncmail.net> 10/29/2003 10:43:45 AM as far as lifes little ironies go... fed ex hasn't come by yet, so I'm told... todd Kevin Baker wrote: Todd: Have adjusted per your comments. All the information is in a FedEx 1 of 8 10/30/03 7:54 AM Re: [Fwd: (no subject)] box on it's way to you. Please call me in the am if you have any questions, or don't receive the package. Thanks for your help! Kevin "Todd St. John" <todd.st.john@ncmail.net> 10/27/2003 2:24:53 PM Sorry, Kevin... -------- Original Message -------- Subject: (no subject) Date: Mon, 27 Oct 2003 14:22:34 -0500 From: Todd St. John <todd.st.john@ncmail.net> Organization: NC DENR DWQ To: mickie@gsoair.org, kjbaker@mbaklercorp.com CC: john.dorney <john.dorney@ncmail.net>, Cyndi Karoly <Cyndi.Karoly@NCMail.Net> Per our meeting today: I decided to email as oppose to fax. I would like to recommend the following additions/modifications to your DRAFT letter that you provided at today's meeting: 1) I think it will be more accurate to describe these devices as flow 2 of 8 10/30/03 7:54 AM Re: [Fwd: (no subject)] spreaders since they will not function like level spreaders as described in our Design Guidance. In other words the purpose of these devices will be to disperse stormwater into the wetlands so that it will cover a certain area of the wetlands as opposed to achieving diffuse flow, for instance. Also, please add the comment that we discussed that additional level spreader length may be provided if USACE approval is obtained to impact the wetland buffer. 3) I think we should specifically add some parameters for grading the basin bottoms to encourage hydrophytic vegetation. For instance, I would suggest something like: The of the bottom of the basin shall be graded and then ripped in such a way to encourage vegetation growth and that shall result in approximately 50% of the basin bottom having small depressions of no more than 20 feet by 20 feet and that average 0.3 3 of 8 10/30/03 7:54 AM Re: [Fwd: (no subject)] to 0.5 feet below the grade shown in the plans. Additionally, small pools at least 3 feet deep and at least 10 feet by 10 feet in size shall be spaced at no more than 100 foot centers to provide refugia for species such as Gambousia [sp?] for mosquito control. Except for the baffles and inlet and outlet structures, the remaining basin bottom should be at or below the grade shown in the plans. I would suggest that the second sentence read something like: Top soil will be stockpiled during construction and and spread along the bottom of the basins to establish the final grade to encourage vegetation growth. Also, I would recommend that you provide a planting plan for the bottom of the basins that 4 of 8 10/30/03 7:54 AM Re: [Fwd: (no subject)] will include the use of a herbaceous wetland seeding mix that will be recommended by MACTEC and that small, native wetland shrubs of at least two species will be planted across approximately 20% of basin floor at a density of 3 to 5 foot centers. The goal of this planting plan will be to provide hydrophytic vegetation that will also discourage geese and other large birds from visiting the basins. Finally, I recommend that you provide as built plans to show that the above has been achieved once the basins are converted to permanent stormwater management devices. 4) "As" should be changed to "If". 5) Please describe why the side slopes are proposed at 2:1. 6) We need some sort of provision in the restored wetlands that would 5 of 8 10/30/03 7:54 AM Re: [Fwd: (no subject)] require repairs that would preclude the formation of any channels and maintain disperse flow of stormwater. That aspect could be worked into the restoration plan but should be addressed in the Operation and Maintenance Agreement. The Operation and Maintenance Agreement (O&M) should address the fact that the dry basin will function like a wetland and that the natural and restored wetlands need to be maintained. I recommend that you review the O&M at http://h2o.ehnr.state.nc.us/ncwetlands/oandm.doc. Additionally, the O&M needs to address the following topics: 1) The natural and restored wetlands need to be inspected every six months. If any areas of erosion or concentrated flow are noted, measures must be immediately taken to repair eroded areas and to disperse concentrated flow. None of these repair or maintenance activities shall be conducted with heavy equipment without written authorization from DWQ and the USACE. Also, during the project construction phase and until the 6 of 8 10/30/03 7:54 AM Re: [Fwd: (no subject)] site is released by DLR the natural wetlands, constructed wetlands (once they are built) and wetland buffers shall be inspected every quarter at a minimum for signs of erosion or sediment accumulation. Repairs to eroded areas and removal of significant accumulated sediment shall be conducted as needed without the use of heavy equipment (unless its use is authorized in writing by the USACE and DWQ). 2) I recommend that the term level spreader be changed to flow spreader. 3) When the basins are maintained. The basin bottoms should be returned to the grade as shown in the as built plans. Also, the disturbed surface must be ripped if compacted and re-vegetated. The following methods of re-vegetation may be used. The top 0.3 feet of the basin bottom may be stockpiled and reapplied to the disturbed area to achieve final 7 of 8 10/30/03 7:54 AM Re: [Fwd: (no subject)] grade. Or the disturbed area shall be revegetated according to the vegetation planting plan above. 8 of 8 10/30/03 7:54 AM 10/30/2003 THU 14:10 FAX 336 931 1501 Baker and Associates m,a-m Engineering and Energy Baker and Associates Fax `transmittal Le er a Don oraehaaearkrcareaeto? Baker and Associates 200 CenhvParf Drive, Suite 225 Greensboro, NC 27409 (336) 931-1500 OUR TELEFAX NO. IS. (336) 931-1501 Date: I C) 156 In To: (Cc (At Receiving From: MESSAGE: IF YOU DO NOT RECEIVE THE NUMBER OF PAGES INDICATED, PLEASE CONTACT OUR OFFICE AS SOON AS POSSIBLE. . . X1001/002 Lie TEMPLATESYFAXTRMSJWC TOTAL. NUMBER OF PACES L (INCLUDING THIS TRANSMITTAL PAGE) 10/30/2003 THU 14;10 FAY 336 931 1501 Baker and Associates 1.: } I? i j ii¢ ?I I' ?rfr M1: i'•? x i sGt1 i fIII1 I ;;?.:: i' t:lr :f? J.I,•:r.f .. I V, ' ?,11''I::a '???•r: ? 002/002 Y'l •:', 61, EM_6RGY dSSIPAT i . \. • - ?_ r R ? ` ?:_ - - tir .? '?l':: i : ?;,:f.rr'^"',?::??_ : ? ?;,?::. ??,,,,..,?„`r. • . ?.?c`?- ..Q:O_R: R.' B/,lS?L11dE- ?-•?,=^? .. - _ RA, • ? --'' : LIMIT QFt bVITf._";, CONSWCM j ' - ) 1; CONC1 y` 1 t. .1 j ,: 1 ?,\.,?•? RAP y - ?? ? 1 ' ? I '' ;,r'.'f':,,?; ? ;ter "?'• ?'? .. _... b ? i` ?? I t?;{?'??". w? 24" Per ?ti,_ i; 1 mot'. !AK _ P SE, 'ROTE 'r` J` l f ?f Eh1Ei? `?_ EE X. SAP.' D15S1PA?%" y. ! S 7H1S: _ET_. Y-? . ?1 s pf? F. 40 SEE SHEET SG17 FOR H <,• J r• t1 .:'??'?..,?' : . • AND VERTICAL LOCATIC ENERGY DISSIPATER TABLE • SEE MCDOT STD, DRAWING #838.27 O SEE NCDOT STD. DRAWING #838.01 WA = NO DISSIPATER REQUIRED - I PIEDMONT TRIAD INTERNATION MIMED -PCL _ PIEPInONT TRIAD AIRPORT AWHORITY GkLEHSk DAAWN woJ M I SAILER AND ASSQCIA, CNEGI?a MICER AND ASSOMTES -25470 $O ?CEfTR NM ItII?SUITI 225 GBEENSI CONSULTING ENGINEERS (336)M41SOO FAM(3361"1-1Sa'I T. - 1 ?:i OF WATER ?O? QG Michael F. Easley Governor William G. Ross, Jr., Secretary Department of Environment and Natural Resources Alan W. Klimek, P.E., Director Division of Water Quality October 30, 2003 Mr. Mickie Elmore Director of Development Piedmont Triad Airport Authority P.O. Box 35445 Greensboro, NC, 27425 Subject: Piedmont Triad Airport Authority Modified Dry Pond/Wetlands DWQ Project No. 000846 Guilford County Dear Mr. Elmore: This Office is in receipt of the plans dated August 20, 2003 with the modifications to the basin baffles received October 29, 2003, the flow spreaders dated October 29, 2003, and for the plan narrative and Operation and Maintenance Agreement dated October 30, 2003 for the three modified dry detention/wetland basins followed by flow spreading devices that will discharge into natural and restored wetlands for the "Fed Ex" portion of the subject facility prepared on your behalf by Baker and Associates and submitted to the Division on October 30, 2003. Staff from the Wetlands Unit reviewed the plans and found them acceptable for the purpose of meeting the requirements of Condition no. 8a of Certification no. 3428 (only). Please note that this approval is for water quality purposes only and shall not be construed as an approval of the design for dam/outlet structure integrity, Dam Safety, public safety, or flood attenuation purposes. If you have any questions regarding this matter, please contact Mr. Todd St. John at (919) 733-9584. Sincerely, ` Jo R. Dorney Wetlands Unit Supervisor cc: Winston-Salem Regional Office USACE Raleigh Regional Office Todd St. John File North Carolina Division of Water Quality, 401 Wetlands Certification Unit, 1650 Mail Service Center, Raleigh, NC 27699-1650 (Mailing Address) 2321 Crabtree Blvd., Raleigh, NC 27604-2260 (Location) 919-733-1786 (phone), 919-733-6893 (fax), http://h2o.enr.state.nc.us/ncwetiands/ WATfi `OHO A?,G Michael F. Easley Governor r William G. Ross, Jr., Secretary 5 _q Department of Environment and Natural Resources n T Alan W. Klimek, P.E., Director Division of Water Quality October 30, 2003 Mr. Mickie Elmore Director of Development Piedmont Triad Airport Authority P.O. Box 35445 Greensboro, NC, 27425 Subject: Piedmont Triad Airport Authority Modified Dry Pond/Wetlands DWQ Project No. 000846 Guilford County Dear Mr. Elmore: This Office is in receipt of the plans dated August 20, 2003 with the modifications to the basin baffles received October 29, 2003, the flow spreaders dated October 29, 2003, and for the plan narrative and Operation and Maintenance Agreement dated October 30, 2003 for the three modified dry detention/wetland basins followed by flow spreading devices that will discharge into natural and restored wetlands for the "FedEx" portion of the subject facility prepared on your behalf by Baker and Associates and submitted to the Division on October 30, 2003. Staff from the Wetlands Unit reviewed the plans and found them acceptable for the purpose of meeting the requirements of Condition no. 8a of Certification no. 3428 (only). Please note that this approval is for water quality purposes only and shall not be construed as an approval of the design for dam/outlet structure integrity, Dam Safety, public safety, or flood attenuation purposes. If you have any questions regarding this matter, please contact Mr. Todd St. John at (919) 733-9584. Si cerely, Jo R. Dorney Wetlands Unit Supervisor cc: Winston-Salem Regional Office USACE Raleigh Regional Office Todd St. John File North Carolina Division of Water Quality, 401 Wetlands Certification Unit, 1650 Mail Service Center, Raleigh, NC 27699-1650 (Mailing Address) 2321 Crabtree Blvd., Raleigh, NC 27604-2260 (Location) 919-733-1786 (phone), 919-733-6893 (fax), http://h2o.enr.state.nc.us/ncwetlands/ Re: Fwd: PTIA seed mix? Subject: Re: Fwd: PTIA seed mix? From: "Kevin Baker" <kjbaker@mbakercorp.com> Date: Thu, 30 Oct 2003 13:55:28 -0500 To: <todd. st. j ohn @ ncmail. net> My understanding is that we are to treat each baffle that way. The detail we sent you will be standard to all ponds/all baffels, unless you direct otherwise. Would you like to see it done differently for each pond? "Todd St. John" <todd.st.john@ncmail.net> 10/30/2003 1:44:01 PM Kevin, is there going to be a low point in the baffle SG111SG10 also? In other words, does that typical apply to both F3 and F2 in about the same place? Kevin Baker wrote: Todd: Karisa Sandiford in our office said that she thinks the fax number may have changed? Is the number I gave you below correct? She's going to try it again at that number, and at another number she thinks may be the new one. She is also scanning the document and will e-mail it. If none of the electron-oriented methods work, call me and I'll drive it over. tx Kevin "Todd St. John" <todd.st.john@ncmail.net> 10/30/2003 12:23:09 PM 1 of 11 10/30/03 1:58 PM Re: Fwd: PTIA seed mix? i do not have the fax... it is not in the machine... Kevin Baker wrote: Todd: Just faxed (to 919/733-9959) revised, signed & notarized 0&M agreement. Let me know if you don't receive it. tx Kevin "Todd St. John" <todd.st.johnCncmail.net> 10/30/2003 9:48:33 AM Yes... i think that would be fine... Kevin Baker wrote: Can we deal with this one by saying that we will seed it with a mix that is approved by DENR at the time? 2 of 11 10/30/03 1:58 PM Re: Fwd: PTIA seed mix? "Todd St. John" <todd.st.john@ncmail.net> 10/30/2003 9:24:21 AM the seed mix sounds like a food plot for deer... some of the species may do ok in wetlands, se... todd Kevin Baker wrote: but it does not sound like a wetland mix per Wetlands was the direction Richard provided. Do you want to see something different? "Todd St. John" <todd.st.john@ncmail.net> 10/30/2003 9:10:55 AM 3 of 11 10/30/03 1:58 PM Re: Fwd: PTIA seed mix? is that proposed seed mix for wetlands or uplands? Kevin Baker wrote: Todd: MACTEC's suggested plantings. See number 8 for my reason on the 10-15 foot centers. tx Kevin "Leatherland, Ben" <BLLEATHERLAND@mactec.com> 4 of 11 10/30/03 1:58 PM Re: Fwd: PTIA seed mix? 10/27/2003 4:14:02 spoke look PM Kevin, Richard Darling asked me to send you potential seed mix recommendations for detention basins at PTIA. He mentioned that one of the main issues would be to discourage waterfowl from using these basins. I with the N.C. Wildlife Resources Commission (NCWRC), and also took a 5 of 11 10/30/03 1:58 PM Re: Fwd: PTIA seed mix? spp.) . at the N.C Erosion and Sediment Control Planning and Design Manual. Here are some suggestions: 1) Use native herbaceous species. Avoid using low grasses (e.g., fescue), as these may attract geese. 2) Avoid using deep-rooting species along dams or berms. 3) Avoid planting Phragmites spp. or cat-tails (Typha 4) Consider letting the detention basin 'naturalize' over time, 6 of 11 10/30/03 1:58 PM Re: Fwd: PTIA seed mix? dam and only periodically remove the largest vegetation. 5) Consider strip mowing along the dam (i.e., mow 1/3 of face each year, and rotate which 1/3 is mowed annually). 6) NCWRC recommends considering the following species, in a seed mix applied at 7 lbs/acre (we've seen similar mixes applied at 15 lbs/acre): 20% - Switchgrass (Panicum virgatum) 20% - Panicgrass (Panicum dichotomiflorum) 20% - Deertongue (Panicum clandestinum) 10% - Orchard grass (Dactylic glomerata) 10% - Alfalfa (Medicago sativa). 10% - Ladino clover (Trifolium repens) 10% - Wheat (Triticum aestivum) in fall/winter 7) Also apply a temporary cover crop of annual rye (Secale cereale) in the autumn, winter, or spring (at 120 lbs/acre), or 7 of 11 10/30/03 1:58 PM Re: Fwd: PTIA seed mix? apply a temporary cover crop of German millet (Setaria italica) in summer (at 40 lbs/acre). 8) Consider seeding or planting (at 10-15 ft on-center) the following woody species also: Serviceberry (Amelanchier spp.) Persimmon (Diospyros virginiana) Black haw (Viburnum prunifolium) Sumac (Rhus coppallina) Black willow (Salix nigra) Please call with any questions. I hope these general suggestions help. Ben Leatherland, P.W.S., CPESC MACTEC Engineering and Consulting, Inc. 8 of 11 10/30/03 1:58 PM Re: Fwd: PTIA seed mix? the 2801 Yorkmont Road, Suite 100 Charlotte, NC 28208 704.357.5610 (direct) 704.357.8638 (fax) blleatherland@mactec.com www.mactec.com MACTEC Engineering and Consulting, Inc. (MACTEC) reserves all copyright rights, but grants a temporary license to the recipient to use materials contained in the attached computer data file for use in development of recipient's work associated with this project. MACTEC said and if does not warrant the accuracy of any information contained in data file. MACTEC assumes no liability for unauthorized alterations alterations to the information contained herein. This e-mail is confidential and legally privileged information. 9 of 11 10/30/03 1:58 PM Re: Fwd: PTIA seed mix? you are not the intended recipient kindly inform the sender immediately and destroy the original and all distribution, disclosure, or the taking of copies. Any copying, any action in reliance on the contents of this e-mail, or part thereof, in any form whatsoever, without the sender's express written consent, is prohibited and may be unlawful. 10 of 11 10/30/03 1:58 PM Engineering and Energy Baker and Associates Fax Transmittal Letter A Dhlskn ofMiehad Baker Corporation Baker and Associates 200 CentrePort Drive, Suite 225 Greensboro, NC 27409 (336) 931-1500 OUR TELEFAX NO. IS: (336) 931-1501 a Date: 10 /Ab tTo: (Cc (At Receiving From: MESSAGE: IF YOU DO NOT RECEIVE THE NUMBER OF PAGES INDICATED, PLEASE CONTACT OUR OFFICE AS SOON AS POSSIBLE. L.WKER TEMPLATESTAXTRANSAOC .. .. J. -.ti::.. _ _ . TOTAL NUMBER OF PAGES 2- (INCLUDING THIS TRANSMITTAL PAGE) 0('- - lk - F, Baker and Associates 200 CentrePort Drive, Suite 225 Greensboro, NC 27409 (336) 931-1500 OUR TELEFAX NO. IS: (336) 931-1501 / lwl 0j }m Date: 1() (36 16 -)"), To: (Company) IUD 4 ? d (Attention) f.i1 - C" 6L Receiving Telecopier No: From:i Ct 13 8a?7 TOTAL NUMBER OF PAGES 3 (INCLUDING THIS TRANSMITTAL PAGE)p? d23'Z MESSAGE: q- Ll/ IF YOU DO NOT RECEIVE THE NUMBER OF PAGES INDICATED, PLEASE CONTACT OUR OFFICE AS SOON AS POSSIBLE. ... '. L:18AKER 7EMPLATESTAXTRANS.DOC . - , ....:. , : • - - Oct-30. 2003 11:42AM PIEDMONT TRIAD AIR DEVELOPMENT No-0347 P. 1 WETLAND-type DETENTION BASIN OPERATION AND MAINTENANCE AGREEMENT The wetland-type detention basin system is defined as the wetland-type detention basin, pretreatment including energy dissipators and flow spreaders. Maintenance activities shall be performed as follows: 1. After every significant runoff producing rainfall event and at least monthly: a. Inspect the detention basin system for sediment accumulation, erosion, trash accumulation, vegetated cover, and general condition. b. Check and clear the orifice of any obstructions such that drawdown of the temporary pool occurs within 2 to 5 days as designed. 2. Repair eroded areas immediately, re-seed as necessary to maintain good vegetative cover, mow vegetative cover on side slopes, and remove trash as needed. 3. Inspect and repair the collection system (i.e. catch basins, piping, swales, riprap, etc.) quarterly to maintain proper functioning. 4. Remove accumulated sediment from the detention basin system semi-annually or when depth is reduced to 75% of the original design depth. Removed sediment shall be disposed of in an appropriate manner and shall be handled in a manner that will not adversely impact water quality (i.e. stockpiling near a detention basin or stream, etc.). The measuring device used to determine the sediment elevation shall be such that it will give an accurate depth reading and not readily penetrate into accumulated sediments. Natural and restored wetlands will be inspected every six months. Corrective action will be taken for any areas of erosion or concentrated flow. Heavy equipment will be used for these repairs only when so approved by NCDENR and USAGE. During project construction, and until the site is release by the DLR, the natural wetlands, constructed wetlands, and wetland buffers will be inspected every quarter for signs of erosion and sediment accumulation. Repairs to eroded areas and removal of accumulated sediment shall be conducted as needed. When basins are maintained, basin bottoms will be returned to the grades shown on the as-built plans. The disturbed surface will be ripped if compacted, and re-vegetated. As necessary, the top 0.3 feet of the basin bottom will be stockpiled and re-applied to the disturbed area to achieve final grade, or the disturbed area shall be re-vegetated according to the vegetation planting plan. 5. If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment through the emergency drain shall be minimized to the maximum extent practical. 6. All components of the detention basin system shall be maintained in good working order. 7. Flow spreaders that provide diffuse flow shall be maintained every six months. All accumulated sediment and debris shall be removed from the structure, and a level elevation shall be maintained across the entire flow spreading structure. Any down gradient erosion must be repaired and/or replanted as necessary. Pala l of 2 Oct-30. 2003 11:42AM PIEDMONT TRIAD AIR DEVELOPMENT No.0341 P. 2 I acknowledge and agree by my signature below that I am responsible for the performance of the seven maintenance procedures listed above. I agree to notify DWQ of any problems with the system or prior to any changes to the system or responsible party. Printname: Title: Address: 64 15 YAN jI &V 6--fte9S 0 0 Phc Sig Dal pp a Notary Public for the State of i i ru, Coun of &-a 1 , do her9by certify that personally appeared before me this ? 5J day of ,,71LY 3, and acknowledge the due execution of the forgoing wetland-type detention basin maintenance requirements. Witness my hand and official seal, SEAL My commission expires o ^ Page 2 of 2 ! / .. - :X" `:'7:.,- •:Y':.!'.'i h - , 5 r:r: :; l.,'rt.':.`:::'1 j'• llli : _ } : G' 1? • . xlI !v r'L' ?•l /:.:: 'v!' e:/two i (?- •,.1.. % ` `:... , ! :'?.:' c` 1 '3; ,':.t• : f. DIS; ) NER Y DISSIPATER'. - l 11501 -- - - ::Jf •r .ij .??Ir... LIMIT-OF • ?: ? - ' t, f Yf'?rif,"'•'•'i.::''?i '`ti4:'; ?';J? ? ??i-' ?CONS71t..(TYPIj-•` _ °??' `?'``-. i # -3EE•SHEE.TS ;?r.r'• ?( X 3 41.; BAFFLE ???: :l a •i,: ` /:'??.':':. /? - Ct . '$` . I..:.rf:';? r ; scn Sct • l' , y/ ?, f : ; ?? . -:?Y __ ?-. ?t i • ?23 rn t'•: BTTE - -IN .. IE _ ?.\ A FL r sGt1i / SGtI rt I O : r• Y -5 :f". D' a _ o _ • t' .t''• 1 {/ .?i` RAP..... i` - :1• - :`'-•.:' . `Rlee'?'RdP: `.? '•. ,o h iPRO_P_OSED• :? -:./ -^',?:::: ``':i.• -\`? •RAMP'. \'?• Ci RCP ,•Csl §G7 V S__ ! g: rj`f'a -T"' '. 4` SEE :NOTE .,, , ?, r'-• J ( :) : :,, -'^_ ?•:? . ,. :'THIS SHE[ ` -? r ENEFf'G? f I TOP OF -B 'i,; ( \` SIP' - ff ? THS.:StIEET` DISSIPA?::,, , !/ • ? - SEE NOTE 1, 1 s .. . F0^ r - ..a. 'PROPOSE c`?1" •,:` .=aL r. ?+. -- .ti60": RCP , SGII 017, t' •?"' s °.P pPOSE_ ter.. SEE SHEET SG77 FOR H .I: •,,Ir 8°=RGI".•• SGt :irt7n. --p.,: ! , '..?••. - AND VERTICAL LOCATIC ?Ii, •' ? Via.: +10, 2935' LT. STA.414f•13, ovw - ENERGY DISSIPATER TABLE M N ELEV 1 ELEV 2 POND PIPE # F G H I 21 9 30.4 MAN 6 O 7.4 18.5 . 6 22 31.67 F3-IN 7 + O 8.6 WA 19 WA . N/A WA F3-IN 8 73 17.02 14.66 16.8 F3-SPILLWAY 9 + SEE NCDOT STD. DRAWING #838.zt O SEE NCDOT STD. DRAWING #838.01 WA = NO DISSIPATER REQUIRED K 1 5 L 16.65 5.1 12.75 820.87 823.54 . 5.38 15.74 5538 12.35 820.87 824.12 WA WA WA WA WA WA 5.46 5.82 5.46 3.26 811.5 816 PIEDMONT TRIAD INTERNATION PIEDMONT TRIAD AIRPORT AUTHORITY GREENS2 BAKER AND ASSOCIA CONSULTING ENGINEERS GREENS[ ? id DESIGNED PCT - DRAWN WDT CHECKED ARB S.O. 25470 OCT-29-2003 WED 02:28 PH ENV SCIENCES BRANCH FAX NO, 919 733 9959 10/29/2003 BBD 14.48 F.I 336 831 1501 Baker and Associates fr_ 0 o ~z zo W LL W W Ry U, LL no W 9 z P. 04/04 9008/008 r- r- E5 N October 30, 2003 Mr. Todd St. John North Carolina Department of Environmental and Natural Resources Division of Water Quality - Wetlands Unit 2321 Crabtree Boulevard Raleigh, NC 27604-2260 Subject: FedEx Development Program Stormwater Management Review Dear Mr. St. John: Per your request, we are providing additional information for the subject effort. We have enclosed the following: ¦ Drawing depicting the stormwater ponds, associated water quality BMP's, and the surrounding natural terrain ¦ Signed/notarized maintenance agreement for the proposed ponds ¦ Surface Area Drainage Area (SADA) calculations for each system ¦ Detail of Baffle tie-ins ¦ Revised detail (typical section) of flow spreaders The proposed system is a modification of the standard BMP manual, as it includes the use of natural and restored wetlands, as well as a modified dry pond that will function like a non-marsh wetland. The proposed system is meant to function like an extended detention wetland. It includes similar design features, such as a 2-5 day detention of the runoff from a 1-inch rain. It provides more surface area than would be required for an extended detension wetland, without the marsh-type characteristics that could endanger aircraft. As we have discussed, during construction, these ponds will function in an E&S role. They will only truly begin to function as stormwater management ponds upon completion of the proposed FedEx development, which is scheduled to occur in the 2008-2009 timeframe. In response to specific issues discussed, we offer the following solutions for the final stormwater management plan: l.) Flow Spreaders have been reconfigured per-our discussion. These will be further lengthened in the field, if such modification is approved by USACE. 2.) Pond F2 Emergency Spillway has been relocated per our discussion. 3.) The bottom of the pond will be graded per your suggestion, with small recesses to form ephemeral ponds. The area will be graded, ripped and topsoiled with stockpiled material to encourage vegetative growth. Specifically, per your suggestion, we propose that approximately 50% of the basin will have small depressions not larger than 20' x 20', and average depth of 3-6 inches. Additional small pools not larger than 10' x 10' and average depth of 3 feet will be provide on approximately 100 foot centers to encourage mosquito control species. The entire basin floor of the ponds will be planted with herbaceous and shrubby vegetation as approved by DWQ. Approximately 20% of the basin floors will be planted with shrubby wet tolerant vegetation to discourage unwanted wildlife on 3-5 foot centers depending on plant size. MACTEC has provided a suggested planting list that is included with this submittal. 4.) If permitted by the USAGE, logs will be placed near the toe of the embankments, and in the natural wetlands to assist with dispersion of higher flows. 5.) Sides of the ponds incorporate 2:1 slopes as recommended by FAA to deter wildlife. The. system will use a combination of dry ponds modified per item three, level spreaders, natural buffer area, and natural wetlands to achieve water quality standards. The attached SADA calculations are based upon DENR criteria for Extended Detention Wetlands, and show that more than adequate area is available. Please feel free to call me at 336/931-1500 with any questions. Sincerely, BAKER AND ASSOCIATES Kevin J. Baker, P.E. Assistant Vice President Enclosures cc: Cindi Karoli, DWQ (w/o Enclosure) M. L. Elmore, PTAA (w/o Enclosure) 10/30/2003 THU 13:52 FAI 336 931 1501 Baker and Associates It! w Engineering and Energy Baker and Associates A O1r sftd of Miohad Baklr CmrMr wn Baker and Assodatas 200 CentrePart Drive, Suite 225 Fax Transmittal Leger Greensboro, NC 27409 1 (336) 9a1-1500 OUR TELEFAX NO. IS: (336)931-1541 J CA IS PO 1 Date: I?ic1 ?}J Q! To: (Company) lU J b' IJ (Attention) -? Receiving Tetecopier No: From: Z001/003 TOTAL NUMBER OF PAGES (INCLUDING THIS TRANSMITTAL PAGE) 108 -- d z3 IF YOU DO NOT RECEIVE THE NUMBER OF PAGES INDICATED, PLEASE CONTACT OUR OFFICE AS SOON AS POSSIBLE. L1 MrM, 10/30/2003 THU 13:52 FA,I 336 931 1501 Baker and Associates ? 002/003 Oct.30. 2003 11.42AM PIEDMONT TRIAD AIR DEVELOPMENT No.0347 P. 1 WETLAND-type DETENTION BASIN OPERATION AND MAINTENANCE AGREEMENT The wetland-type detention basin system is defined as the wetland-type detention basin, pretreatment including energy dissipators and flow spreaders- Maintenance activities shall be performed as follows: 1. After every significant runoff producing rainfall event and at least monthly. a. Inspect the detention basin system for sediment accumulation, erosion, trash accumulation, vegetated cover, and general condition. b. Check and clear the orifice of any obstructlons such that drawdown of the temporary pool occurs within 2 to 5 days as designed. 2. Repair eroded areas immediately, reseed as necessary to maintain good vegetative cover, mow vegetative cover on side slopes, and remove trash as needed. 3. Inspect and repair the collection system (Le- catch basins, piping, swales, riprap, etc-) quarterly to maintain proper functioning. 4. Remove accumulated sediment from the detention basin system semi-annually or when depth is reduced to 75% of the original design depth- Removed sediment shall be disposed of in an appropriate manner and shall be handled In a manner that wig not adversely impact water quality (i.e. stockpiling near a detention basin or stream, etc.)- The measuring device used to determine the sediment elevation shall be such that it will give an accurate depth reading and not readily penetrate into accumulated sediments. Natural and restored wetlands will be inspected every six months. Corrective action will be taken for any areas of erosion or concentrated flow. Heavy equipment will be used for these repairs only when so approved by NMENR and USACE. During project construction, and until the site is release by the DLR, the natural wetlands, constructed wetlands, and wetland buffers will be inspected every quarter for signs of erosion and sediment accumulation. Repairs to eroded areas and removal of accumulated sediment shall be conducted as needed. When basins are maintained, basin bottoms will be returned to the grades shown on the as-built plans. The disturbed surface will be ripped if compacted, and re-vegetated- As necessary, the top 4.3 fleet of the basin bottom will be stockpiled and re-applied to the disturbed area to achieve final grade, or the disturbed area shall be re-vegetated according to the vegetation planting plan. 5. If the basin must be dralned for an emergency or to perform maintenance, the flushing of sediment through the emergency drain shall be minimized to the maximum extent practical. 6. All components of the detention basin system shall be maintained in good working order. 7. Flow spreaders that provide diffuse flow shall be maintained every six months. All accumulated sediment and debris shall be removed from the structure, and a level elevation shall be maintained across the entire flow spreading structure- Any down gradient erosion must be repaired and/or replanted as necessary. Page t oft 10/30/2003 THU 13:53 FAI 336 931 1501 Baker and Associates Z003/003 Oct-30. 2003 11,-L2AM PIEDMONT TRIAD AIR DEVELOPMENT No-OW P. 2 1 acknowledge and agree by my signature below that I am responsible fear the performance of the seven maintenance procedures listed above. I agree to notify DWQ of any problems with the system or prior to any changes to the system or responsible party. Print narne; G k? P, L 1 a I, 1 a Notary Public for the State of i County of t , do heby certify that , personally appeared before me this _day of and acknowledge the due execution of the forgoing wetland-type detention basin maintenance requirements. Witness my hand and official seal, SEAL My commission expires d ^ - Page 2 of 2 Title. . + t? Address. 64 (no subject) Subject: (no subject) From: "Todd St. John" <todd.st.john@ncmail.net> Date: Mon, 27 Oct 2003 14:22:34 -0500 To: mickie@gsoair.org, kjbaker@mbaklercorp.com CC: "john.dorney" <john.dorney@ncmail.net>, Cyndi Karoly <Cyndi. Karoly @ NCMai1. Net> Per our meeting today: I decided to email as oppose to fax. I would like to recommend the following additions/modifications to your DRAFT letter that you provided at today's meeting: 1) I think it will be more accurate to describe these devices as flow spreaders since they will not function like level spreaders as described in our Design Guidance. In other words the purpose of these devices will be to disperse stormwater into the wetlands so that it will cover a certain area of the wetlands as opposed to achieving diffuse flow, for instance. Also, please add the comment that we discussed that additional level spreader length may be provided if USACE approval is obtained to impact the wetland buffer. 3) I think we should specifically add some parameters for grading the basin bottoms to encourage hydrophytic vegetation. For instance, I would suggest something like: The of the bottom of the basin shall be graded and then ripped in such a way to encourage vegetation growth and that shall result in approximately 500 of the basin bottom having small depressions of no more than 20 feet by 20 feet and that average 0.3 to 0.5 feet below the grade shown in the plans. Additionally, small pools at least 3 feet deep and at least 10 feet by 10 feet in size shall be spaced at no more than 100 foot centers to provide refugia for species such as Gambousia [sp?] for mosquito control. Except for the baffles and inlet and outlet structures, the remaining basin bottom should be at or below the grade shown in the plans. I would suggest that the second sentence read something like: Top soil will be stockpiled during construction and and spread along the bottom of the basins to establish the final grade to encourage vegetation growth. Also, I would recommend that you provide a planting plan for the bottom of the basins that will include the use of a herbaceous wetland seeding mix that will be recommended by MACTEC and that small, native wetland shrubs of at least two species will be planted across approximately 200 of basin floor at a density of 3 to 5 foot centers. The goal of this planting plan will be to provide hydrophytic vegetation that will also discourage geese and other large birds from visiting the basins. Finally, I recommend that you provide as built plans to show that the above has been achieved once the basins are converted to permanent stormwater management devices. . 4) "As" should be changed to "If" . 5) Please describe why the side slopes are proposed at 2:1. 1 of 2 10/27/03 3:02 PM (no subject) 6) We need some sort of provision in the restored wetlands that would require repairs that would preclude the formation of any channels and maintain disperse flow of stormwater. That aspect could be worked into the restoration plan but should be addressed in the operation and maintenance Agreement. The Operation and Maintenance Agreement (0&M) should address the fact that the dry basin will function like a wetland and that the natural and restored wetlands need to be maintained. I recommend that you review the O&M at http://h2o.ehnr.state.nc.us/ncwetlands/oandm.doc. Additionally, the O&M needs to address the following topics: 1) The natural and restored wetlands need to be inspected every six months. If any areas of erosion or concentrated flow are noted, measures must be immediately taken to repair eroded areas and to disperse concentrated flow. None of these repair or maintenance activities shall be conducted with heavy equipment without written authorization from DWQ and the USACE. Also, during the project construction phase and until the site is released by DLR the natural wetlands, constructed wetlands (once they are built) and wetland buffers shall be inspected every quarter at a minimum for signs of erosion or sediment accumulation. Repairs to eroded areas and removal of significant accumulated sediment shall be conducted as needed without the use of heavy equipment (unless its use is authorized in writing by the USACE and DWQ). 2) I recommend that the term level spreader be changed to flow spreader. 3) When the basins are maintained. The basin bottoms should be returned to the grade as shown in the as built plans. Also, the disturbed surface must be ripped if compacted and re-vegetated. The following methods of re-vegetation may be used. The top 0.3 feet of the basin bottom may be stockpiled and reapplied to the disturbed area to achieve final grade. Or the disturbed area shall be revegetated according to the vegetation planting plan above. 2 of 2 10/27/03 3:02 PM Baker and Associates A Unit of Michael Baker Corporation 200 CentrePort Drive, Suite 225 Greensboro, NC 27409 (336) 931-1500 FAX (336) 931-1501 October 28, 2003 Mr. Todd St. John North Carolina Department of Environmental and Natural Resources Division of Water Quality - Wetlands Unit 2321 Crabtree Boulevard Raleigh, NC 27604-2260 Subject: FedEx Development Program Stormwater Management Review Dear Mr. St. John: WETLANDS 1401 GROUP OCT 2 9 2003 WATER QUALITY SECTION Per your request, we are providing additional information for the subject effort. We have enclosed the following: ¦ Drawing depicting the stormwater ponds, associated water quality BMP's, and the surrounding natural terrain ¦ Signed/notarized maintenance agreement for the proposed ponds ¦ Surface Area Drainage Area (SADA) calculations for each system ¦ Detail of Baffle tie-ins ¦ Revised detail (typical section) of flow spreaders As we have discussed, during construction, these ponds will function in an E&S role. They will only truly begin to function as stormwater management ponds upon completion of the proposed FedEx development, which is scheduled to occur in the 2008-2009 timeframe. In response to specific issues discussed, we offer the following solutions for the final stormwater management plan: 1.) Flow Spreaders have been reconfigured per our discussion. These will be further lengthened in the field, if such modification is approved by USACE. 2.) Pond F2 Emergency Spillway has been relocated per our discussion. 3.) The bottom of the pond will be graded per your suggestion, with small recesses to form ephemeral ponds. The area will be graded and topsoiled with stockpiled material to encourage vegetative growth. Specifically, per your suggestion, we propose that approximately 50% of the basin will have small depressions not larger than 20' x 20', and average depth of 3-6 inches. Additional small pools not larger than 10' x 10' and average depth of 3 feet will be provide on approximately 100 foot centers to encourage mosquito control species. The ponds will be planted with herbaceous and shrubby vegetation as recommended by Mactec, to a total of approximately 20% of the basin floors on 10-15 foot centers (as recommended by MACTEC). MACTEC has provided a list of recommended species, which is included in the attached e-mail. 4.) If permitted by the USACE, logs will be placed near the toe of the embankments, and in the natural wetlands to assist with dispersion of higher flows. 5.) Sides of the ponds incorporate 2:1 slopes as recommended by FAA to deter wildlife. The system will use a combination of dry ponds modified per item three, level spreaders, natural buffer area, and natural wetlands to achieve water quality standards. The attached SADA calculations are based upon DENR criteria for Extended Detention Wetlands, and show that more than adequate area is available. Please feel free to call me at 336/931-1500 with any questions. Sincerely, BAKE AND ASSOCIATES Kevin J. Baker, P.E. Assistant Vice President Enclosures cc: Cindi Karoli, DWQ (w/o Enclosure) M. L. Elmore, PTAA (w/o Enclosure) O O O W W W> m m m'J? J J J Q Q Q I V L co 'IT 'IT oq 'a' M M 11 II II r N M Q Q Q D O D N M c Cl Q Cl 0 O 0 [A N In to to U U U '? U U U M (0 (C M <0 cC m I,- LO r 00 t- I,- o9 O) 00 M II M M N 0. L O ? m Q Q CL 4) (D r N M O 't co O O N co a- U r O II II It O O O O (0 (a (u (0 (n (/? N _ E Q r N M O ? ? ? d ? LL D Q n N G1 ? m o t/f v rn ?O N mn O Z v DO TI min r m rn I Z --I 0 NOS 1 40?. ??®?? WE?1A 0r-I %-t TV WPlERwwV Secl`olt? LVI WE?'NDS I Q01 loci 9 *No ,QUPV a` ' C l oo? 003 ??? ?5? Z N T r G CA ma M m D v m m ul ? 22 Z tmi? oF-F, o0 o? 0 WETLAND-type DETENTION BASIN OPERATION AND MAINTENANCE AGREEMENT The wetland-type detention basin system is defined as the wetland-type detention basin, pretreatment including energy dissipators and flow spreaders. Maintenance activities shall be performed as follows: After every significant runoff producing rainfall event and at least monthly: a. Inspect the detention basin system for sediment accumulation, erosion, trash accumulation, vegetated cover, and general condition. b. Check and clear the orifice of any obstructions such that drawdown of the temporary pool occurs within 2 to 5 days as designed. 2. Repair eroded areas immediately, re-seed as necessary to maintain good vegetative cover, mow vegetative cover to maintain a maximum height of six inches, and remove trash as needed. 3. Inspect and repair the collection system (i.e. catch basins, piping, swales, riprap, etc.) quarterly to maintain proper functioning. 4. Remove accumulated sediment from the detention basin system semi-annually or when depth is reduced to 75% of the original design depth (see diagram below). Removed sediment shall be disposed of in an appropriate manner and shall be handled in a manner that will not adversely impact water quality (i.e. stockpiling near a detention basin or stream, etc.). The measuring device used to determine the sediment elevation shall be such that it will give an accurate depth reading and not readily penetrate into accumulated sediments. Natural and restored wetlands and wetland buffers will be inspected every six months. Corrective action will be taken for any areas of erosion or concentrated flow. Heavy equipment will be used for these repairs only when so approved by NCDENR and USACE. When basins are maintained, basin bottoms will be returned to the grades shown on the as-built plans. As necessary, the top 0.3 feet of the basin bottom will be stockpiled and re-applied to the disturbed area to achieve final grade, or the disturbed area shall be revegetated according to the vegetation planting plan. 5. If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment through the emergency drain shall be minimized to the maximum extent practical. 6. All components of the detention basin system shall be maintained in good working order. 7. Flow spreaders that provide diffuse flow shall be maintained every six months. All accumulated sediment and debris shall be removed from the structure, and a level elevation shall be maintained across the entire flow spreading structure. Any down gradient erosion must be repaired and/or replanted as necessary. Page 1 of 2 I acknowledge and agree by my signature below that I am responsible for the performance of the seven maintenance procedures listed above. I agree to notify DWQ of any problems with the system or prior to any changes to the system or responsible party. Print name: ( t? L ?I mvte a Title: Note: The legally responsible party should not be a homeowners association unless more than 50% of the lots have been sold and a resident of the subdivision has been named the president. I, , a Notary Public for the State of b County of L 2 , do herby certify that personally appeared before me this C?M day of clq- 'e. and acknowledge the due execution of the forgoing wetland-type detention basin maintenance requirements. Witness my hand and official seal, SEAL ?t My commission expires Page 2 of 2 z74og Address: &4r lb Kt(A,J 61-VD. DVA-rr October 27, 2003 Mr. Todd St. John North Carolina Department of Environmental and Natural Resources Division of Water Quality - Wetlands Unit 2321 Crabtree Boulevard Raleigh, NC 27604-2260 Subject: FedEx Development Program Stormwater Management Review Dear Mr. St. John: Per your request, we are providing additional information for the subject effort. We have enclosed a drawing depicting the stormwater ponds, associated water quality BMP's, and the surrounding natural terrain. Also enclosed is a signed/notarized maintenance agreement for the nproposed ponds, and Surface Area Drainage Area (SARA) calculations for each pond. 94"14n response to specific issues discussed, we offer the following: 1.) Level Spreaders have been reconfigured per our discussion. 2.) Pond F2 Emergency Spillway has been relocated per our discussion. d 3.) The bottom of the pond will be graded per your suggestion, with small recesses to s/T t (? form ephemeral ponds. The area will be topsoiled to encourage vegetative growth. ?G 4.) j ? permitted by the USACE, logs will be placed near the toe of the embankments, W' and in the natural wetlands to assist with dispersion of higher flows. The syste will use a combination of dry ponds modified per item three, level spreaders, natural buffer area, and natural wetlands to achieve water quality standards. The attached SADA calculations are based upon DENR criteria for Extended Detention Wetlands, and show that more than adequate area is available. Please feel free to call me at 336/931-1500 with any questions. Sincerely, BAKER AND ASSOCIATES G? r SS? Kevin J. Baker, P.E. AV Assistant Vice President f 60, Enclosures d? cc: Cindi Karoli, DWQ (w/o Enclosure) M. L. Elmore, PTAA (w/o Enclosure) P 15Z Kz2;- _f- 33b 13/ /FV) DRY DETENTION BASIN OPERATION AND MAINTENANCE AGREEMENT The dry detention basin system is defined as the dry detention basin, associated energy dissipators and level spreaders. Maintenance activities shall be performed as follows: After every significant runoff producing rainfall event and at least monthly: a. Inspect the dry detention basin system for sediment accumulation, erosion, trash accumulation, vegetated cover, and general condition. b. Check and clear the orifice of any obstructions such that drawdown of the temporary pool occurs within 2 to 5 days as designed. 2. Repair eroded areas immediately, re-seed as necessary to maintain good vegetative cover, mow vegetative cover to maintain a maximum height of six inches, and remove trash as needed. 3. Inspect and repair the collection system (i.e. catch basins, piping, swales, riprap, etc.) quarterly to maintain proper functioning. 4. Remove accumulated sediment from the dry detention basin system semi-annually or when temporary pool depth is reduced to 75% of the original design depth (see diagram below). Removed sediment shall be disposed of in an appropriate manner and shall be handled in a manner that will not adversely impact water quality (i.e. stockpiling near a dry detention basin or stream, etc.). The measuring device used to determine the sediment elevation shall be such that it will give an accurate depth reading and not readily penetrate into accumulated sediments. When the elevation of the sediment areas exceed the designed temporary pool elevation, the sediment should be removed to design levels. The basin will be seeded and mulched again following removal of the sediment. `* gl? All components of the dry detention basin system shall be maintained in good working order. 6. Level spreaders or other structures that provide diffuse flow shall be maintained every six months. All accumulated sediment and debris shall be removed from the structure, and a level elevation shall be maintained across the entire flow spreading structure. Any down gradient erosion in must be repaired and/or replanted as necessary. I acknowledge and agree by my signature below that I am responsible for the performance of the maintenance procedures listed above. I agree to notify DWQ of any problems with the system or prior to any changes to the system or responsible party. Print name: Title: Address: Phone: Signature: Date: Page 1 of 2 a Notary Public for the State of , County of , do hereby certify that personally appeared before me this day of , and acknowledge the due execution of the forgoing dry detention basin maintenance requirements. Witness my hand and official seal, SEAL My commission expires Page 2 of 2 OCT-29-2003 WED 02:19 PM ENV SCIENCES BRANCH FAX NO, 919 733 9959 10/29/2003 WED 14;47 FA% 336 931 1501 Baker and Associates Eno[ ne?King andnwrey Baker and Associates ADMdara/AfthW40 C60NOW Fax Transmittal Letter Saker and Assn WOS 280 Cemmpott twW, Suite 225 Greensboro, NC 27909 (338) 9,11400 OUR TELEFAX NO. 15. (336) 931-1501 a Date, To: (Company) -- (AtfenEion} D ReWvft -foleoopler tdb: From: 1?0 Y! h T6.1 .et( _. - - -- -- J TOTAL NUMBER OF PAOEs B. (INCLUmo YW TRAN816TTAL PAGE) P. 01 gaol/008 IF YOU DO NOT RECEIVE THE NUMBER OF PAGES INDICATED, PLEASE CONTACT OUR OFFICE AS SOON AS POSSIBLE. ,. ,. .raeaxs?zrwwsaras+rrunwws.ooc ? .. .. ,., ., ., ? ...........:.:? ,•,:.str,, .. ...... ....., , ,??,: .. OCT-29-2003 WED 02,19 PM ENV SCIENCES BRANCH FAX NO. 919 733 9959 10/29/2003 WED 14.47 FAX 338 931 1001 Baker and Associates Ta (336) 931-1500 FAX (336 931-1601 October 26, 2003 Mr. Todd St. John North Carolina Department of Environmental and Natural Resources Division of Watac Quality - Wetlands Unit 232t Crabtree Boulevard Raleigh, NC 276042260 Subject: FedE.x Development Program Stormwater Management Review Dear Mr. 5t. John-. Per your reques4 we are providing additional infonnadon for the subject effort, We have enclosed the following: ¦ Drawing depicting the stotmwater ponds, associated water quality BMP's, and the surrounding natural terrain • Signedlnotatizcd maintenance agreement for the proposed ponds ¦ Surface Area Drainage Area (SARA) calculations for each systems ¦ Detail of BaM* tie-ins ¦ Revised detail (typical section) of flow spreaders As we have discussed, during construction, these ponds will function in an US role. 't'hey will only truly begin to Ammon as stormwater mia ugement ponds upon completion of the proposed FW& development, which is scheduled to occur in the 2009-2009 timeframc, in response to specific issues discassad, we offer the following solutions for the final storrawater marmSemert plan: 1.) Flow Spreaders have been reconfigured. per our discussion. These will be hither lengthened in the #kki. if such modification is approved by USACE. 2.) Pond F2 Emergency Spillway has been relocated per our discussion. 3.) The bottom of the pond will be graded per your suggestion, with small recesses to form ephemeral ponds. The area will be graded and top-soiled with stockpiled material to encourage vegetative growth. Spocifrcally, per your suawtion, we propose that, approximately 501% of the basin will save small depressions not larger than 20' x 20', and average depth of 3-6 inches. Additional small pools not larger than 10'x 10' and avcrage-depth of 3 feet will be provide on approximately 100 foot centers to encourage mosquito control species. The ponds will be planted with herbaceous and shrubby vegetation as recommended by Mactec, to a total of approximately 200% of the basin floors on 10-15 foot centers (as r mommended by P. 02 1002/00$ OCT-29-2003 WED 02:20 PN ENV SCIENCES BRANCH FAX NO, 919 733 9959 P. 03 10/29/2003 fil)11:48 FAI 336 931 1601 Baker and Associates gQ03/908 IvtACIEC). MACIEC has provided a list of recommended species, which is included in the attached a-mail. 4.) If permitted by the USACE, logs will be placed new the toe of the embanlonents, and the natural wetlands to assist with dispersion of higher flows. 5,) Sides of the ponds incorporate 2:1 slopes as recommended by FAA to deter wildlife, The system will use a combination of dry ponds modified per item throe, level spreaders, natural buffer area, and natural wetlands to achieve water quality standards. The attached SARA calculations are based upon DEW criteria for Extendod Detention. Wetlands, and show that more than adequate area is available. Please feel free to call me at 336/931-1$00 with any questions. i Sincerely, . BAK t?ND ASSOCIATES Keviti T. Baker, P.E. Assistant Vice President Enclosures cc: Cindi Karoli DWQ (w/o Enclosure) M. L. Elmore, PTAA (w/o Enclosure) OCT-29-2003 WED 02:20 PM ENV SCIENCES BRANCH FAX NO. 919 733 9959 P. 04 10/29/2003 WED 14;48 FAI 336 931 1501 Baker and Associates gm /m Iti ri r C ? W 8 Q df - ? a ? u": OCT-29-2003 WED 02:20 PM ENV SCIENCES BRANCH FAX NO. 919 733 9959 P. 05 10/29/2003 14,48 FAX 336 931 1601 Baker and Associates A005/008 WETLAND-type DETENTION BASIN OPERATION AND MAINTCNANCE AGREEMENT The wetland-type detention basin system Is deiined as the wetland-type detention basin, pretreatment including energy dissipators and flow spreaders. Maintenance activities shall be performed as follows: 1. After every signfiicant runoff producing rainfall event and at least monthly: a. inspect the detention basin system for sediment accumulation, erosion, trash accumulation, vegetated cover, and general condition. b. Check and dear the orifice of any obstructions such that drawdown of the temporary pool occurs within 2 to 5 days as designed. 2. Repair eroded areas immediately, re-seed as necessary to maintain good vegetative cover, mow vegetative cover to maintain a maximum height of six inches, and remove trash as needed. 3. Inspect and repair the collection system (i.e. catch basins, piping, swales, rlprap, etc.) quarterly to maintain proper functioning. 4. Remove accumulated sediment from the detention basin system seml-annually or when depth Is reduced to 76% of the original design depth (see diagram below). Removed sediment shall be disposed of in an appropriate manner and shall be handled in a manner that will not adversely impact water quality (i.e. stockpiling near a detention basin or stream, etc.). The measuring device used to determine the sediment elevation shall be such that it will give an accurate depth reading and not readily penetrate into accumulated sediments. Natural and restored wetlands and wetland buffers wiN be inspected every six months. Corrective action will be taken for any areas of erosion or concentrated flow. Heavy equipment will be used for these repairs only when so approved by NCDENR and USACE. When basins are maintained, basin bottoms will be returned to the grades shown on the as-built plans. As necessary, the top 0.3 feet of the basin bottom will be stockpiled and reapplied to the disturbed area to achieve final grade, or the disturbed area shall be revegetated according to the vegetation planting plan. 5. If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment through the emergency drain shall be minimized to the maximum extent practical. 6. All components of the detention basin system shall be maintained in good working order. 7. now spreaders that provide diffuse flow shall be maintained every six months. All accumulated sediment and debris shall be removed from the structure, and a level elevation shall be maintained across the entire flow spreading structure. Any down gradient erosion must be repaired and/or replanted as necessary. Page t of 2 OCT-29-2003 WED 02:27 PM ENV SCIENCES BRANCH FAX NO. 919 733 9959 10/29/2003 WED 14:48 M 336 931 1501 faker and Associates P. 01/04 WETLAND-typo DETENTION BASIN OPERATION AND MAJNTENANCE AGREEMENT The wetland-type detention basin system Is defined as the wetland-type detention basin, pretreatment including energy dissipators and flow spreaders. Maintenance activities shall be performed as follows: 1. After every significant nurwff producing rainfall event and at least monthly: a. Inspect the detention basin system for sediment accumulation, erosion, trash accumulation, vegetated cover, and general condition. b. Check and clear the orifice of any obstructions such that drawdown of the temporary pool occurs within 2 to 5 days as designed. 2, Repair eroded areas Immediately, re-seed as necessary to maintain good vegetative cover, mow vegetative cover to maintain a maximum height of six inches, and remove trash as needed. 3. inspect and repair the collection system (i.e. catch basins, piping, sweles, dprep, etc.) quarterly to maintain proper functioning. 4. Remove accumulated sediment from the detention basin system semi-annually or when depth Is reduced to 75% of the original design depth (see diagram below). Removed sediment shall be disposed of in an appropriate manner and shall be handled In a manner that will not adversely impact water quality (i.e. stockpiling near a detention basin or stream, etc.). The measuring device used to determine the sediment elevation shalt be such that it will give an accurate depth reading and not readily penetrate into accumulated sediments. Natural and restored wetlands and wetland buffers wiN be inspected every six months. Corrective action will be taken for any areas of erosion or concentrated flow. Heavy equipment will be used for these repairs only when so approved by NCDENR and tlSACE. When basins are maintained, basin bottoms will be returned to the grades shown on the as-built plans. As necessary, the top 0.3 feet of the basin bottom will be stockpiled and re-applied to the disturbed area to achieve final grade, or the disturbed area shall be revegetated according to the vegetation planting plan. 5 N the basin must be drained for an emergency or to perform maintenance, the flushing of sediment through the emergency drain shall be minimized to the maxlrnum extent practical. 6. All components of the detention basin system shall be maintained In good working order. 7. Flow spreaders that provide diffuse flaw shall be matntained every six months. All accumulated sediment and debris shall be removed from the structure, and a level elevation shall be maintained across the entire flow spreading structure. Any down gradient erosion must be repaired and/or replanted as necessary. 0 Page 1 of 2 OCT-29-2003 WED 02:27 PM ENV SCIENCES BRANCH FAX NO, 919 733 9959 10/29/2003 WED 14:48 FAI 336 931 1501 Baker and Associates P. 02/04 @006/008 I acknowledge and agree by my signature below that 1 am responsilAe for the performance of the seven maintenance procedures listed above. I agree to notify DWQ of any problems with the system or prior to any changes to the system or responsible party. Print name: ia 9 L I iLimyfp -------___--- Note; The legally responsible party should not be a homeowners association unless more than 6A'61' the lots have been soW and a resident of the subdivision has been named the president. 1, a Notary Public jfr the State of County of OU-i 14" do he y certify/that _ personally appeared before me this day of Ci J(' b?e jjXZ and acknowledge the due execution of the forgoing wetland-type detention basin maintenance requirements. Witness my hand and official seal, SEAL My commission expires- / " OCT-29-2003 WED 02:28 PM ENV SCIENCES BRANCH FAX NO. 919 733 9959 10/29/2003 IED 14;48 FAI 336 931 1501 Baker and Associates CY ? ltd C5 i' i? f r J ! ! f ? r i 1 1 r f I •y r f ? 0 ?a wLA a ! r r f I I wz I 99 W Q a W ce. 0 J LL. P. 03/04 J009/008 W26/2003 FRI 12:07 FAX 336 931 1501 Baker and Associates 900t/003 Engineering and Energy Bskor and Associates Fax Tranam ittal Letter A DIdaton of Uki" Baker QwMrj*n Baker and Associates ?? I r„ 200 CentrePort Drive, Suite 225 `fi1 ?'("J Greensboro, NC 27409 (336) 931-1500 OUR TELEFAX NO. IS: (336) 931-1501 ??D Date: To: (Company) AIC_ EAM - We?Saijs Jki (Attention) Receiving Telecopier No: Ck {9 3 & From: TOTAL NUMBER OF PAGES (INCLUDING THIS -TRANSMITTAL PAGE) -rb MESSAGE: HtbL61eei. el 3 ?icte___?CQll? aye-r" e. -tor Pore -r- r - NL 72 EX fuhl Sti"rG. Q1en??, _r+?(l i ? ` .? O U ?UQ art a Ol y.-E3'fio„.S _ or IF YOU DO NOT RECEIVE THE NUMBER OF PAGES INDICATED, PLEASE CONTACT OUR OFFICE AS SOON AS POSSIBLE. . L%AKER T"LATEffAKM N1SDOC . 7 7 09/26/2003 FRI 12:07 FAX 336 931 1501 Baker and Associates r ? . I., I rol. .a N O •p C 9 d C 9002/003 V) 09/26/2003 FRI 12.07 FAI 336 931 1501 Baker and Associates V03/003 • :.? t__ -;?; : cam. ??;' , • - ? • is - -_ _?• ? - ? r ? ?. .....r ?.- ,r . .'v f_ b I -_ : = = _; 1 - r- FED EX stormwater plan Subject: FED EX stormwater plan From: "Todd St. John" <todd.st.john@ncmail.net> Date: Fri, 26 Sep 2003 08:45:42 -0400 To: mickie@gsoair.org CC: John.dorney" <john.dorney@ncmail.net>, Cyndi Karoly <Cyndi.Karoly@NCMail.Net>, "daryl.lamb" <daryl.lamb@ncmail.net> Mickie, (I seem to have lost Kevin's email address, could you please forward this to him?) As we discussed yesterday during our meeting, it does not appear that you will be able to meet the 85% TSS removal requirement for a WSIII watershed by traditional means. However, the Wetalnds Unit does believe that a combination of created or designed wetlands the will discharge via flow dispersing devices into natural and restored wetlands can achieve the above requirement. I have made this determination based on the extent of the existing natural wetlands and by suggesting revisions to the existing plans as we discussed yesterday. The following is a summary of the necessary revisions to the plan: 1) The length, width, design and location of the flow spreading devices and the emergency spillway must be modified as we discussed and hand-drew on the plans. The width of the flow spreading devices must also be maximized. If the USACE agrees, the lip must be constructed of hard material such as block, concrete, or other materials to achieve precise, even flow. If not the lip must be precisely graded, compacted and stabilized to provide even flow. 2) The bottoms of the detention basins must be graded and ripped to encourage small ephemeral pond areas thereby creating a constructed wetland. We can discuss exact grading parameters later. We would also want to apply 4" to 8" inches of top soil (if available) to encourage vegetation growth. 3) As we discussed, we would like to explore the use of hand-placed natural materials such as logs, etc. generated by the site construction to help maintain and maximize dispersed flow into and in the wetlands (pending USACE agreement). 4) The Operation and Maintenance Agreement will also have to be crafted to reflect the need to conduct hand repairs and maintenance in the existing, natural wetlands as well as normal maintenance of the basins and flow dispersion devices. 5) There were other items that we discussed that we all agreed would be provided. 1 of 2 9/26/03 9:03 AM FED EX stonnwater plan This email is not the formal approval of your stormwater plan for the FED Ex phase, but is intended to provide confirmation of what we discussed. I discussed these concepts with John and Cyndi and we are willing to accept the concepts if they can be achieved. Thanks, todd 2 of 2 9/26/03 9:03 AM Sunset Beach - 2003 April 2003 6 13 20 27 S 4 I1 8 25 S I 8 15 22 29 S 6 13 20 27 S 3 10 7 24 3l S 7 14 21 28 S 5 12 9 26 S 2 9 16 23 30 S 7 14 21 28 S 4 11 18 25 S 8 15 22 29 S 7 14 21 28 Subject ?.ev?/ eaC?e-, Ty?vica,l gyros -.Iwbon Page No. of The Business of Airports www.mbakercorp.com Michael F. Easley Governor William G. Ross, Jr., Secretary Department of Environment and Natural Resources Alan W. Klimek, P.E., Director Division of Water Quality September 19, 2003 Mr. Kevin Baker, PE Baker and Associates 200 Centre Port Drive, Suite 225 Greensboro, NC 27409 Subject: Dear Mr. Baker: FedEx Development Program DWQ Project No. 000846 Guilford County The Wetlands Unit staff reviewed the stormwater management plans for the subject project and determined that additional information is necessary to complete the technical review process. The required additional information is as follows: Site Plans 2. 3. 4. 5. 6. 7 Please provide a set of full sized site plans that includes all of the detail requested below. Temporary Water Quality Pool You indicated that the runoff from the one inch rain will be used to size the temporary water quality related volume to be stored and release over a 4 day period. Please provide that volume for each pond. Also, please provide a worksheet for each dry detention basin available at http://h2o.ehnr.state.nc.us/ncwetlands/mitresto.html. Conditions 8, 9, 10, and 11 of the 401 Water Quality Certification Please review conditions 8, 9, 10 and 11 of the 401 Water Quality Certification no. 3428. Each of these conditions has interrelated aspects that must be integrated with the current proposed stormwater management plan. It is recommended that a meeting be set up to discuss these issues and how the conditions can be met. I thought we had a meeting scheduled for September 17, 2003, but apparently it was not confirmed. Draw Down Orifice Outlet Please provide additional detail regarding the orifice installed directly through the end cap. Please provide protection of the outlet from debris. Forebays It is not clear from the plans provided for ponds F2 and F3 will prevent short circuiting or provide a 3:1 flow path. Please reconfigure the berms to lengthen the flow path. Vegetated Side Slopes The basin side slopes above the permanent pool down to the vegetative shelf should be stabilized with vegetation and side slopes no steeper than 3:1 (horizontal to vertical). The bottom of the basins should also be vegetated. We had previously discussed the types of vegetation that may be acceptable in regards to FAA safety guidelines. Level Spreaders Level spreaders must be designed according to the Level Spreader Design Options available at http://h2o.ehnr.state.nc.us/ncwetlands/level.pdf with the intent to provide a forested filter strip as described in the North Carolina Division of Water Quality, 401 Wetlands Certification Unit, 1650 Mail Service Center, Raleigh, NC 27699-1650 (Mailing Address) 2321 Crabtree Blvd., Raleigh, NC 27604-2260 (Location) 919-733-1786 (phone), 919-733-6893 (fax), http://h2o.enr.state.nc.us/ncwetlands/ Page 2 of 2 NC DENR Stormwater Best Management Practices Manual. It is not clear that the level spreaders have actually been designed or provided (The plan detail is very small and I cannot clearly see the contours). It is essential the level spreaders be precisely level as well as able to withstand the flows that enter them and those that overflow the lip. The proposed lengths appear to be inadequate based on the 10 year discharge entering them. It is recommended that the discharge from the orifice that draws down the captured runoff from the 1" rain be isolated and sent to the level spreader. In any event, the discharge from the level spreader as well as the receiving (infiltration) area down to the nearest stream or other feature that would tend to intercept the flow and concentrate it must be independent from that of larger discharges. Additionally, the larger discharges cannot be released at a velocity that would be erosive to the receiving area, buffer or wetland. In this case, the discharges that will be entering the level spreader. The presumed level spreaders provided also appear to be discharging onto very steep slopes. This issue must also be addressed. It will also be necessary to provide an adequate site plan to show the distance of flow and existing topography down to any intercepting feature that will tend to concentrate the flow. Also, it is not clear from the plans provided what the fate of the flows from the level spreaders will be. The level spreaders must be located in the most optimal location to provide the greatest amount of flow diffusion and infiltration, particularly into the existing wetlands. It is my anticipation that the proposed ponds.and outlets will have to be reconfigured to meet these criteria. Please provide a typical detail for the level spreaders. The typical plans must show appropriate materials for and design of the lip and that adequate flow dissipation will be provided to prevent the flow from discharging in a concentrated manner (or jumping) at any point along the spreading device. The proposed dissipaters may be adequate to slow the discharge but it is not clear whether or not the discharge would jump over the level spreader at the discharge point during larger discharge events. Please fill out a worksheet for each level spreader used. These are available at hftp://h2o.ehnr.state.nc.us/ncwetiands/mitresto.html. 8. Drainage Area Stormwater BMPs must be designed to treat all of the runoff draining to the basin. Please provide the site plans including the collection system draining to each basin. Also, the purpose and function of the junction chamber (SG10, JC1) is not clear. Please provide and explanation. 9. Worksheets Please provide a worksheet for each dry detention basin and level spreader available at hftp://h2o.ehnr.state.nc.us/ncwetiands/mitresto.html. 10. Operation and Maintenance Agreement An operation and maintenance agreement is required. An example operation and maintenance plan can be found at http://h2o.ehnr.state.nc.us/ncwetlands/mitresto.html. The operation and maintenance agreement must also be signed by the responsible party and notarized. If you have any questions or would like to discuss this project, please contact me at (919)733-9584. Also, please note that the NC DENR Stormwater Best Management Practices Manual as well as other documents and information can be downloaded from the Wetlands Unit web site at http://h2o.ehnr.state.nc.us/ncwetlands/mitresto.htmi. Sincerely, v Todd St. John, PE Environmental Engineer cc: Winston-Salem Regional Office Cyndi Karoly File t/q A N QG Michael F. Easley Governor William G. Ross, Jr., Secretary Department of Environment and Natural Resources Alan W. Klimek, P.E., Director Division of Water Quality September 19, 2003 Mr. Kevin Baker, PE Baker and Associates 200 Centre Port Drive, Suite 225 Greensboro, NC 27409 Subject: FedEx Development Program DWQ Project No. 000846 Guilford County Dear Mr. Baker: The Wetlands Unit staff reviewed the stormwater management plans for the subject project and determined that additional information is necessary to complete the technical review process. The required additional information is as follows: 1. Site Plans Please provide a set of full sized site plans that includes all of the detail requested below. 2. Temporary Water Quality Pool You indicated that the runoff from the one inch rain will be used to size the temporary water quality related volume to be stored and release over a 4 day period. Please provide that volume for each pond. Also, please provide a worksheet for each dry detention basin available at http://h2o.ehnr.state.nc.us/ncwetlands/mitresto.html. 3. Conditions 8, 9, 10, and 11 of the 401 Water Quality Certification Please review conditions 8, 9, 10 and 11 of the 401 Water Quality Certification no. 3428. Each of these conditions has interrelated aspects that must be integrated with the current proposed stormwater management plan. It is recommended that a meeting be set up to discuss these issues and how the conditions can be met. I thought we had a meeting scheduled for September 17, 2003, but apparently it was not confirmed. 4. Draw Down Orifice Outlet Please provide additional detail regarding the orifice installed directly through the end cap. Please provide protection of the outlet from debris. 5. Forebays It is not clear from the plans provided for ponds F2 and F3 will prevent short circuiting or provide a 3:1 flow path. Please reconfigure the berms to lengthen the flow path. 6. Vegetated Side Slopes The basin side slopes above the permanent pool down to the vegetative shelf should be stabilized with vegetation and side slopes no steeper than 3:1 (horizontal to vertical). The bottom of the basins should also be vegetated. We had previously discussed the types of vegetation that may be acceptable in regards to FAA safety guidelines. 7. Level Spreaders Level spreaders must be designed according to the Level Spreader Design Options available at http://h2o.ehnr.state.nc.us/ncwetlands/level.pdf with the intent to provide a forested filter strip as described in the North Carolina Division of Water. Quality, 401 Wetlands Certification Unit, 1650 Mail Service Center, Raleigh, NC 27699-1650 (Mailing Address) 2321 Crabtree Blvd., Raleigh, NC 27604-2260 (Location) 919-733-1786 (phone), 919-733-6893 (fax), http://h2o.enr.state.nc.us/ncwetlands/ Page 2 of 2 NC DENR Stormwater Best Management Practices Manual. It is not clear that the level spreaders have actually been designed or provided (The plan detail is very small and I cannot clearly see the contours). It is essential the level spreaders be precisely level as well as able to withstand the flows that enter them and those that overflow the lip. The proposed lengths appear to be inadequate based on the 10 year discharge entering them. It is recommended that the discharge from the orifice that draws down the captured runoff from the 1" rain be isolated and sent to the level spreader. In any event, the discharge from the level spreader as well as the receiving (infiltration) area down to the nearest stream or other feature that would tend to intercept the flow and concentrate it must be independent from that of larger discharges. Additionally, the larger discharges cannot be released at a velocity that would be erosive to the receiving area, buffer or wetland. In this case, the discharges that will be entering the level spreader. The presumed level spreaders provided also appear to be discharging onto very steep slopes. This issue must also be addressed. It will also be necessary to provide an adequate site plan to show the distance of flow and existing topography down to any intercepting feature that will tend to concentrate the flow. Also, it is not clear from the plans provided what the fate of the flows from the level spreaders will be. The level spreaders must be located in the most optimal location to provide the greatest amount of flow diffusion and infiltration, particularly into the existing wetlands. It is my anticipation that the proposed ponds.and outlets will have to be reconfigured to meet these criteria. Please provide a typical detail for the level spreaders. The typical plans must show appropriate materials for and design of the lip and that adequate flow dissipation will be provided to prevent the flow from discharging in a concentrated manner (or jumping) at any point along the spreading device. The proposed dissipaters may be adequate to slow the discharge but it is not clear whether or not the discharge would jump over the level spreader at the discharge point during larger discharge events. Please fill out a worksheet for each level spreader used. These are available at hftp://h2o.ehnr.state.nc.us/ncwetiands/mitresto.htmi. 8. Drainage Area Stormwater BMPs must be designed to treat all of the runoff draining to the basin. Please provide the site plans including the collection system draining to each basin. Also, the purpose and function of the junction chamber (SG10, JC1) is not clear. Please provide and explanation. 9. Worksheets Please provide a worksheet for each dry detention basin and level spreader available at hftp://h2o.ehnr.state.nc.us/ncwetlands/mitresto.htmi. 10. Operation and Maintenance Agreement An operation and maintenance agreement is required. An example operation and maintenance plan can be found at http://h2o.ehnr.state.nc.us/ncwetlands/mitresto.htmi. The operation and maintenance agreement must also be signed by the responsible party and notarized. If you have any questions or would like to discuss this project, please contact me at (919)733-9584. Also, please note that the NC DENR Stormwater Best Management Practices Manual as well as other documents and information can be downloaded from the Wetlands Unit web site at http://h2o.ehnr.state.nc.us/ncwetlands/mitresto.htmi. Sincerely, Todd St. John, PE Environmental Engineer cc: Winston-Salem Regional Office Cyndi Karoly File WAT pG September 19, 2003 Mr. Kevin Baker, PE Baker and Associates 200 Centre Port Drive, Suite 225 Greensboro, NC 27409 Subject: Dear Mr. Baker: Michael F. Easley Governor William G. Ross, Jr., Secretary Department of Environment and Natural Resources Alan W. Klimek, P.E., Director Division of Water Quality FedEx Development Program DWQ Project No. 000846 Guilford County The Wetlands Unit staff reviewed the stormwater management plans for the subject project and determined that additional information is necessary to complete the technical review process. The required additional information is as follows: Site Plans Please provide a set of full sized site plans that includes all of the detail requested below. 2. Temporary Water Quality Pool You indicated that the runoff from the one inch rain will be used to size the temporary water quality related volume to be stored and release over a 4 day period. Please provide that volume for each pond. Also, please provide a worksheet for each dry detention basin available at http://h2o.ehnr.state.ne.us/ncwetlands/mitresto.htnil. 3. 4. 5. 6. 7. Conditions 8, 9, 10, and 11 of the 401 Water Quality Certification Please review conditions 8, 9, 10 and 11 of the 401 Water Quality Certification no. 3428. Each of these conditions has interrelated aspects that must be integrated with the current proposed stormwater management plan. It is recommended that a meeting be set up to discuss these issues and how the conditions can be met. I thought we had a meeting scheduled for September 17, 2003, but apparently it was not confirmed. Draw Down Orifice Outlet Please provide additional detail regarding the orifice installed directly through the end cap. Please provide protection of the outlet from debris. Forebays It is not clear from the plans provided for ponds F2 and F3 will prevent short circuiting or provide a 3:1 flow path. Please reconfigure the berms to lengthen the flow path. Vegetated Side Slopes The basin side slopes above the permanent pool down to the vegetative shelf should be stabilized with vegetation and side slopes no steeper than 3:1 (horizontal to vertical). The bottom of the basins should also be vegetated. We had previously discussed the types of vegetation that may be acceptable in regards to FAA safety guidelines. Level Spreaders Level spreaders must be designed according to the Level Spreader Design Options available at http://h2o.ehnr.state.nc.us/ncwetlands/level.pdf with the intent to provide a forested filter strip as described in the North Carolina Division of Water. Quality, 401 Wetlands Certification Unit, 1650 Mail Service Center, Raleigh, NC 27699-1650 (Mailing Address) 2321 Crabtree Blvd., Raleigh, NC 27604-2260 (Location) 919-733-1786 (phone), 919-733-6893 (fax), http://h2o.enr.state.nc.us/ncwetlands/ Page 2of2 NC DENR Stormwater Best Management Practices Manual. It is not clear that the level spreaders have actually been designed or provided (The plan detail is very small and I cannot clearly see the contours). It is essential the level spreaders be precisely level as well as able to withstand the flows that enter them and those that overflow the lip. The proposed lengths appear to be inadequate based on the 10 year discharge entering them. It is recommended that the discharge from the orifice that draws down the captured runoff from the 1" rain be isolated and sent to the level spreader. In any event, the discharge from the level spreader as well as the receiving (infiltration) area down to the nearest stream or other feature that would tend to intercept the flow and concentrate it must be independent from that of larger discharges. Additionally, the larger discharges cannot be released at a velocity that would be erosive to the receiving area, buffer or wetland. In this case, the discharges that will be entering the level spreader. The presumed level spreaders provided also appear to be discharging onto very steep slopes. This issue must also be addressed. It will also be necessary to provide an adequate site plan to show the distance of flow and existing topography down to any intercepting feature that will tend to concentrate the flow. Also, it is not clear from the plans provided what the fate of the flows from the level spreaders will be. The level spreaders must be located in the most optimal location to provide the greatest amount of flow diffusion and infiltration, particularly into the existing wetlands. It is my anticipation that the proposed ponds.and outlets will have to be reconfigured to meet these criteria. Please provide a typical detail for the level spreaders. The typical plans must show appropriate materials for and design of the lip and that adequate flow dissipation will be provided to prevent the flow from discharging in a concentrated manner (or jumping) at any point along the spreading device. The proposed dissipaters may be adequate to slow the discharge but it is not clear whether or not the discharge would jump over the level spreader at the discharge point during larger discharge events. Please fill out a worksheet for each level spreader used. These are available at http://h2o.ehnr.state.nc.us/ncwetlands/mitresto.htmI. 8. Drainage Area Stormwater BMPs must be designed to treat all of the runoff draining to the basin. Please provide the site plans including the collection system draining to each basin. Also, the purpose and function of the junction chamber (SG10, JC1) is not clear. Please provide and explanation. 9. Worksheets Please provide a worksheet for each dry detention basin and level spreader available at http://h2o.ehnr.state.nc.usincwetlands/mitresto.html. 10. Operation and Maintenance Agreement An operation and maintenance agreement is required. Ad example operation and maintenance plan can be found at http://h2o.ehnr.state.nc.us/ncwetlands/mitresto.html. The operation and maintenance agreement must also be signed by the responsible party and notarized. If you have any questions or would like to discuss this project, please contact me at (919) 733-9584. Also, please note that the NC DENR Stormwater Best Management Practices Manual as well as other documents and information can be downloaded from the Wetlands Unit web site at http://h2o.ehnr.state.nc.us/ncwetlands/mitresto.html. Sincerely, Todd St. John, PE Environmental Engineer cc: Winston-Salem Regional Office Cyndi Karoly File W AT F9 II??QG Michael F. Easley Governor William G. Ross, Jr., Secretary Department of Environment and Natural Resources Alan W. Klimek, P.E., Director Division of Water Quality February 21, 2003 Mr. Alan R. Berenbrok, P.E. Baker and Associates 200 CenterPort Drive, Suite 225 Greensboro, NC 27409 Subject: Dry Basins F1, F2 and F3 PTAA DWQ Project No. Guilford County Dear Mr. Berenbrok: The Wetlands Unit staff reviewed the stormwater management plans for the subject ponds that are part of this project. In order to receive final approval for these ponds further information would be necessary. The additional information is as follows: . Temporary Water Quality Pool It is presumed that the temporary water quality pool volume has changed from previous submittals. It will be necessary to provide the calculations and volume to be stored. . Dry Basin Location It is not clear where the dry basins are to be located at the facilities. . Inlet/Outlet Structure Location The inlet and outlet structures of F2 and F3 must be placed to minimize short circuiting and turbulence. A long flow path will help to maximize the settling efficiency of the water quality structure. You had previously indicated that a flow path of 3:1 would be provided. This may be achieved by configuring the forebay berms to create a longer flow path, for instance. A . Level Spreaders Level spreaders should be designed according to the Level Spreader Design Options available at http://h2o.ehnr.state.nc.us/ncwetlands/level.pdf. The level spreader length must be sized to accommodate the maximum release rate as opposed to the maximum release rate from the 1" rain draw down orifice, unless the only discharge to the level spreader is from the 1" rain draw down orifice. The latter does not appear to be the case in this situation. It maybe necessary to reconfigure the discharge outlets and/or emergency spill ways so that all of the discharges beyond that of the 1" rain draw down orifice bypass the level spreader/filter strip system. Y¥. Remainder of the Stormwater Management Plan As you mentioned in your correspondence, there have been several additions and revisions to the stormwater management plan for this project over an extended period of time. As such, it is no longer clear which aspects of the plans and revisions that have been submitted are still applicable. As such, I recommend that a summary of the current stormwater management plan, as it relates to the application for 401 Water Quality Certification, be completely and at one time, resubmitted. The submittal should contain the specific BMPs proposed, the specific drainage areas tributary to the specific BMPs, the amount or percentage of anticipated impervious area in each North Carolina Division of Water Quality, 401 Wetlands Certification Unit, 1650 Mail Service Center, Raleigh, NC 27699-1650 (Mailing Address) 2321 Crabtree Blvd., Raleigh, NC 27604-2260 (Location) 919-733-1786 (phone), 919-733-6893 (fax), http://h2o.enr.state.nc.u6/ncwetlands/ Page 2 of 2 drainage area, and other BMP sizing information used in your calculations. The submittal should also include the pertinent design information for each BMP, such as temporary storage volumes, surfaces areas, swale lengths, etc. Also, specific references to previously submitted detailed aspects of the plans should be provided, if applicable. Please note that it is important that adequate areas and site locations be provided that will allow for the construction of BMPs that will meet the DWQ design criteria for 85% TSS removal for each drainage area. I understand that you may have provided most or all of this information previously. However, as stated above due to the extended period of time and number of various submittals and revisions, I am no longer certain which aspects of the plan are correct. As such, to avoid any potential delays in a decision in regards to the 401 Water Quality Certification application. I recommend providing a summary each time any part of the stormwater management plan is revised and submitted to this Office. This will help clarify which revisions are current. . Worksheets Worksheets for dry basins, stormwater ponds, wetlands, grassed swales, level spreaders and bioretention areas can be found at http://h2o.ehnr.state.nc.us/ncwetlands/mitresto.htmi. Also, an example operation and maintenance agreement can be found at http://h2o.ehnr.state.nc.us/ncwetlands/mitresto.html. If you have any questions or would like to discuss this project, please contact me at (919) 733-9584. Also, please note that the NC DENR Stormwater Best Management Practices Manual as well as other documents and information can be downloaded from the Wetlands Unit web site at http://h2o.ehnr.state.ne.us/ncwetlands/mitresto.htmi. Sincerely, Todd St. John, PE Environmental Engineer cc: Winston-Salem Regional Office File STATE OF NORTH CAROLINA DEPARTMENT OF n` ENVIRONMENT, HEALTH .NATURAL RESOURCES L DIVISION OF WATER QUALITY Administrative Code Section: 15A NCAC 2H.0500 Water Quality Certification Amended Effective: October 1, 1996 tSrA7Zc Environmental P".r la Management Commission ??. 'I Raleigh; North Carolina's n r J -, ;, ?` ji '? ??, :? EHNR - ENVIRONMENTAL MANAGEMENT T15A: 02H .0500 SECTION .0500 - WATER QUALITY CERTIFICATION .0501 PURPOSE (a) The provisions of this Section shall apply to all division regulatory, planning, resource management, liaison and financial aid determinations that affect surface waters and wetlands as defined by 15A NCAC 2B .0202. This Section shall only apply to specific activities which require state review after the effective date of this Rule and which require a Division determination concerning effects on surface waters or wetlands. Activities that are described in Section 404(f)(1)(A)-M of the Clean Water Act (33 U.S.C. 1344) are exempt from this Rule. (b) These Rules outline the application and review procedures for activities that require water quality certifications (certifications) pursuant to Section 401 of the Clean Water Act (33 U.S.C. 1341). Certifications are required whenever construction or operation of facilities will result in a discharge into navigable waters as described in 33 CFR Part 323. The federal definition of navigable waters includes wetlands as defined at 33 CFR 328.3 and' 40 CFR 230.3. (c) Certifications may be issued for individual activities (individual certifications) or issued for specific types or groups of activities (general certifications): (1) Individual certifications are issued on a case-by-case basis and the procedures outlined in the following Rules are required for each individual certification. (2) General certifications are issued for specific types or groups of activities that are similar in nature and considered to have minimal impact. The application and review procedures for requesting concurrence from the Division that the general certification can be used for the proposed activity are the same as the procedures outlined in the following Rules for individual certifications unless specifically stated otherwise in the general certification. History Note: Authority G.S. 143-215.3(a)(1), 143-215.3(c); 143B-282(1)(u), RRC Objection Eff. July 18, 1996 due to lack of statutory authority and ambiguity, Eff. October 1, 1996. .0502 APPLICATION (a) Application for Certification. Any person, as defined in Article 21, Chapter 143, North Carolina General Statutes, desiring issuance of the state certification or coverage under a general certification required by Section 401 of the Federal Water Pollution Control Act as amended shall file with the Director of the North Carolina Division of Water Quality (director), at the office in Raleigh, North Carolina, an original and six copies of an application for certification. Submission of an application to the Division of Coastal Management for permits to develop in North Carolina's coastal area shall suffice as an application for certification. The application shall specify: (1) the date of application; (2) the name, address, and phone number of the property owner; (3) if the applicant is a corporation, the state in which it is domesticated, the name of its principal officers, the name and address of the North Carolina process agency, and the name of the individual who shall be primarily responsible for the conduct of the activity for which certification is sought; (4) the nature of the activity to be conducted by applicant; (5) whether the discharge has occurred or is proposed; (6) the location of the discharge, stating the municipality, if applicable; the county; the drainage basin; the name of the receiving waters; and the location of the point of discharge with regard to the receiving waters; (7) a description of the receiving waters, including type (creek, river, swamp, canal, lake, pond or estuary) if applicable; nature (fresh, brackish or salt); and wetland classification; (8) description of the type of waste treatment facilities if applicable. (b) Maps. There shall be attached to the application a map(s) or sketch(es) of sufficient detail to accurately delineate the boundaries of the lands owned or to be utilized by the applicant in carrying out its activity; the location, dimensions and type of any structures erected or to be erected on said lands for use in connection with the activity; and the location and extent of the receiving waters including wetlands within the boundaries of said lands. (c) Power to Request Additional Information. The Director may request, and the applicant shall furnish, any additional information that may be found necessary for the proper consideration of the application. (d) Omissions From Applications. If the applicant considers that it is not feasible or is unnecessary to furnish any portion of the information required by Paragraphs (a) and (b) of this Rule, applicant shall submit a detailed NORTH CAROLINA ADMINISTRATIVE CODE 10115196 Page 1 EHNR - ENVIRONMENTAL MANAGEMENT TISA: 02H.0500 statement explaining the reasons for omission of any such information. (e) Investigations. The staff of the Department of Environment, Health, and Natural Resources (department) shall conduct such investigation as the Director deems necessary; and applicant shall cooperate in the investigation to the extent that it shall furnish necessary information, allow the staff safe access to the lands and facilities of the applicant and lend such assistance as shall be reasonable. (f) Who Must Sign Applications. The application shall be considered a "valid application" only if the application bears the signature of a responsible officer of the company, municipal official, partner or owner. This signature certifies that the applicant has title to the property, has been authorized by the owner to apply for certification or is a public entity and has the power of eminent domain. Said official in signing the application shall also certify that all information contained therein or in support thereof is true and correct to the best of his knowledge. (g) An application form may be obtained from the Division of Water Quality, the Division of Coastal Management, or the U.S. Army Corps of Engineers, Wilmington District, Regulatory Branch. History Note: Authority G.S. 143-215.3(a)(1); 143-215(c), 143B-282(1)(u); E„ f `: February 1, 1976, Amended Eff. December 1, 1984; January 1, 1979; RRC Objection Eff. July 18, 1996 due to lack of statutory authority and ambiguity; Recodifted from 15A NCAC 2H. 0501 E„ . October 1, 1996; Amended Eff. October 1, 1996. .0503 PUBLIC NOTICE (a) Notice by Publication. Notice of each pending application for an individual certification shall be published one time in a newspaper having general circulation in the county in which the discharge will occur, or as provided in Paragraph (c) of this Rule. Publication shall be made at least 15 days prior to proposed final action by the Director upon the application and not more than 20 days after acceptance of a completed application. (b) Contents of Notice. The notice shall set forth the name and address of the applicant; the action requested in the application; the nature and location of the discharge; and the proposed date of final action to be taken by the Director upon the application. The notice shall also state that additional information is on file with the department and may be inspected at any time during normal working hours. Copies of such information on file shall be made available upon request and upon payment of the cost thereof to the department. (c) The public notice requirement may also be satisfied by a joint notice with the Division of Coastal Management (15A NCAC 7J .0206) or the U.S. Army Corps of Engineers according to their established procedures. (d) Notice of Hearing. If the Director determines that a hearing should be held concerning the granting or denial of the application, the Director shall publish notice of the hearing one time in a newspaper having general circulation in the county in which the discharge will occur. The notice shall be published at least 30 days prior to the date of the hearing. The notice shall state the time, place and nature of the hearing. (e) Water Quality Certification Mailing List. Any person, may request that he or she be mailed copies of all public notices required by this Rule. The Director shall add the name of any such person to a water quality certification mailing list and shall mail copies of notices to all persons on the list. (f) Payment of Costs of Public Notice. The applicant shall pay to, the department the costs of advertising public notice required by Paragraphs (a) and (d) of this Rule. Certification shall be withheld until such costs have been paid. History Note. Authority G .S. 143-215.3(a)(1), 143-215.3(c), 143B-282(1)(u), E„f: February 1, 1976; Amended Eff. December 1, 1984; September 1, 1984 RRC Objection Eff. July 18, 1996 due to lack of statutory authority and ambiguity; Recodied from 15A NCAC 2H.0502 Eff October 1, 1996, Amended Eff. October 1, 1996 .0504 HEARING (a) Public Hearing on Certification. If the Director determines that it is in the public interest that a public hearing for the purpose of reviewing public comment and additional information be held prior to granting or denying certification, the Director shall so notify the applicant by registered or certified mail, return receipt requested, and shall publish and give notice as required in Rule .0503(d) and (e) of this Section. Such hearing shall be held within 90 days following date of notification. The record of each hearing held under this Paragraph shall remain open for a period of 30 days. .1 NORTH CAROLINA ADMINISTRATIVE CODE 10115196 Page 2 EHNR - ENVIRONMENTAL MANAGEMENT T15A: 02H.0500 (b) Hearing for Applicant Upon Certification Denial. An applicant whose certification is denied or granted subject to unacceptable conditions, shall have the right to a contested case hearing pursuant to the provisions of G.S. 150B-23. History Note. Authority G.S. 143-215.3(a)(1); 143-215.3(c); 143B-282(1)(u); Eff. February 1, 1976; Amended E„ . July 1, 1988; December 1, 1984; RRC Objection E„f: July 18, 1996 due to lack of statutory authority and ambiguity; Recodified from 15A NCAC 2H. 0503 Eff. October 1, 1996; Amended Eff. October 1, 1996. .0505 DELEGATIONS History Note. Authority G.S. 143-215.3(a)(1), 143-215.3(c); Eff. February 1, 1976; Repealed Eff. December 1, 1984. .0506 REVIEW OF APPLICATIONS (a) In evaluating requests for certification based on the procedures outlined in Paragraphs (b) through (e) of this Rule, the Director shall determine if the proposed activity has the potential to remove or degrade those significant existing uses which are present in the wetland or surface water. Activities which would not remove or degrade existing uses shall be reviewed according to the procedures found in Subparagraph (c)(2)-(5) of this Rule. Those activities covered by general certifications [15A NCAC 2H .0501(c)(2)] which do not require written concurrence from the Division shall be deemed certified if the conditions of the certification are followed and may proceed without the review procedures outlined in Paragraphs (b) through (e) of this Rule. An applicant may also demonstrate that designated uses are not present at a particular site using a wetland evaluation procedure approved by the Director according to the criteria found in 15A NCAC 2B .0103(c); otherwise the designated uses as outlined at 15A NCAC 2B .0231(a)(1)-(6) are assumed to exist in all classes of wetlands, and the appropriate review procedures shall be undertaken. Certification shall be issued where the Director determines water quality standards are met, including protection of existing uses. (b) The Director shall issue a certification upon determining that existing uses are not removed or degraded by a discharge to classified surface waters for an activity which: (1) has no practical alternative under the criteria outlined in Paragraph (f) of this Rule; (2) will minimize adverse impacts to the surface waters based on consideration of existing topography, vegetation, fish and wildlife resources, and hydrological conditions under the criteria outlined in Paragraph (g) of this Rule; (3) does not result in the degradation of groundwaters or surface waters; (4) does not result in cumulative impacts, based upon past or reasonably anticipated future impacts, that cause or will cause a violation of downstream water quality standards; (5) provides for protection of downstream water quality standards through the use of on-site stormwater control measures; and (6) provides for replacement of existing uses through mitigation as described at Subparagraphs (h)(1) of this Rule. (c) The Director shall issue a certification upon determining that sufficient existing uses are not removed or degraded by a discharge to Class WL wetlands as defined at 15A NCAC 2B .0101(c)(8), for an activity which: (1) has no practical alternative as described in Paragraph (f) of this Rule, or impacts less than three acres of Class WL wetlands; (2) will minimize adverse impacts to the wetland based on consideration of existing topography, vegetation, fish and wildlife resources, and hydrological conditions under the criteria outlined in Paragraph (g) of this Rule; or impacts less than one acre of wetland within 150 feet (including less than 1/3 acre of wetland within 50 feet), of the mean high water line or normal water level of any perennial or intermittent water body as shown by the most recently published version of the United State Geological Survey 1:24,000 (7.5 minute) scale topographical map or other site specific data; (3) does not result in the degradation of groundwaters or surface waters; (4) does not result in cumulative impacts, based upon past or reasonably anticipated future impacts, that cause or will cause a violation of downstream water quality standards; (5) provides protection for downstream water quality standards through the use of on-site stormwater control NORTH CAROLINA ADMINISTRATIVE CODE 10115196 Page 3 EHNR - ENVIRONMENTAL MANAGEMENT TISA: 02H .OS00 measures; and (6) provides for replacement of existing uses through wetland mitigation under U.S. Army Corps of Engineers requirements or as described in Subparagraph (h)(1)-(8) of this Rule. (d) The Director shall issue a certification upon determining that significant existing uses are not removed or degraded by a discharge to Class SWL wetland as defined at 15A NCAC 2B .0101(d)(4),wetlands that are contiguous to waters designated as ORW, HQW, SA, WS-I, WS-1I or Trout, or wetlands that are contiguous to rivers designated as a North Carolina or National Wild and Scenic River for an activity which satisfies Subparagraphs (c)(2)-(5) of this Rule, and: (1) for wetlands classified as coastal wetlands pursuant to 15A NCAC 7H .0205: (A) has no practical alternative as described in Paragraph (f) of this Rule; and (B) is water dependent and requires access to water as a central element of its basic function, although, projects funded by government agencies may be exempted from this requirement; and (2) provides for replacement of existing uses through wetland mitigation under U.S. Army Corps of Engineers requirements, or as described in Subparagraphs (h)(1)-(7) and (9) of this Rule. (e) The Director shall issue a certification upon determining that significant existing uses are not removed or degraded by a discharge to wetlands of exceptional state or national ecological significance including but not limited to Class UWL wetlands, and wetlands that have been documented to the satisfaction of the Director as habitat essential for the conservation of state or federally listed threatened or endangered species, provided that the wetlands have been so classified or designated prior to the date of application for certification or a draft environmental impact statement has been submitted to the Director, for an activity which satisfies Subparagraphs (c)(2)-(5) and (d)(1)-(2) and: (1) the wetland impacts are necessary for the proposed project to meet a demonstrated public need; and (2) provides for replacement of existing uses through wetland mitigation under U.S. Army Corps of Engineers requirements, or as described in Subparagraphs (h)(1)-(7) and (10) of this Rule. (f) A lack of practical alternatives may be shown by demonstrating that, considering the potential for a reduction in size, configuration or density of the proposed activity and all alternative designs the basic project purpose cannot be practically accomplished in a manner which would avoid or result in less adverse impact to surface waters or wetlands. (g) Minimization of impacts may be demonstrated by showing that the surface waters or wetlands are able to continue to support the existing uses after project completion, or that the impacts are required due to: (1) The spatial and dimensional requirements of the project; or (2) The location of any existing structural or natural features that may dictate the placement or configuration of the proposed project; or (3) The purpose of the project and how the purpose relates to placement, configuration or density. (h) Replacement or mitigation of unavoidable losses of existing uses shall be reviewed in accordance with the following guidelines: (1) The Director shall coordinate mitigation requirements with other permitting agencies that are requiring mitigation for a specific project. Mitigation required by the U.S. Army Corps of Engineers shall be considered to constitute the mitigation required by the certification unless the Director determines that the mitigation proposal does not meet the criteria established in Subparagraph (6) of this Paragraph. (2) Mitigation shall not be required for impacts to Class WL wetlands of less than one acre. (3) Participation in wetland restoration programs coordinated by the Department of Environmental, Health, and Natural Resources shall be preferred to individual project mitigation whenever the Director finds that such participation is available and satisfies the other requirements of this Paragraph, unless the applicant can demonstrate that participation in these restoration programs is not practical. Mitigation sites approved by the U.S. Army Corps of Engineers shall be deemed to be consistent with the Department's restoration plan. (4) Acceptable methods of wetlands mitigation are listed below in the order of preference: (A) Restoration: the re-establishment of wetland hydrology and vegetation in an area where it previously existed. (B) Creation: the construction of a wetland in an area where wetlands did not exist in the recent past. (C) Enhancement: increasing one or more of the functions of an existing wetland by manipulation of vegetation or hydrology. (D) Preservation: protection of wetlands through purchase, donation or conveyance of a conservation easement to an appropriate government or non-profit agency for management. (5) Restoration is the preferred method of wetlands mitigation. The other methods may be utilized if the applicant can demonstrate that restoration is not practical or that the proposed alternative is the most . V NORTH CAROLINA ADMINISTRATIVE CODE 10/15196 Page 4 EHNR - ENVIRONMENTAL MANAGEMENT T15A: 0211.0500 ecologically viable method of replacing the lost functions and values. (6) All mitigation proposals shall provide for the replacement of wetland acres lost due to the proposed activity at a minimum of a 1:1 ratio through restoration or creation prior to utilizing enhancement or preservation to satisfy the mitigation requirements, unless the Director determines that the public good would be better served by other types of mitigation. (7) Wetlands mitigation shall be conducted based on the following ratios (acres mitigated to acres loss); 4:1, for wetlands located within 150 feet of the mean high water line or normal water level of any perennial or intermittent water body as shown by the most recently published version of the United States Geological Survey 1:24,000 (7.5 minute) scale topographical map; 2:1, for wetlands located between 150 feet and 1,000 feet from the mean high water line or normal water level of any perennial or intermittent water body as shown by the most recently published version of the United States Geological Survey 1:24,000 (7.5 minute) scale topographical map; and 1:1, for all other wetlands. For linear projects which impact less than 3 acres of wetlands the ratio shall be 2:1 regardless of the distance from surface waters. The above ratios apply only to restoration. The acres of required mitigation for the other types of mitigation shall be determined by multiplying the above ratios by 1.5 for creation, 2 for enhancement, and 5 for preservation. The above ratios do not apply to approved mitigation sites where the state and federal review agencies have approved credit/debit ratios. This Subparagraph shall not apply to general certifications until the Department has established a wetlands restoration program or until January 1, 1997, whichever occurs first. (8) Mitigation for impacts to wetlands designated in Paragraph (c) of this Rule shall be conducted within the same river basin and physiographic province when practical. Unavoidable losses of wetlands adjacent to waters classified as WS-III shall be replaced within the water supply watershed when practical. (9) Mitigation for impacts to wetlands designated in Paragraph (d) of this Rule shall be of the same wetland type and located within the same river sub-basin when practical. Mitigation for impacts to wetlands adjacent to waters classified as WS-I or WS-II shall be replaced within the water supply watershed when practical. (10) Mitigation for impacts to wetlands designated in Paragraph (e) of this Rule shall be of the same wetland type and within the same watershed when practical. (i) The Director shall not duplicate the site-specific application of any guidelines employed by the United State Army Corps of Engineers in evaluating permit applications under 33 U.S.C. 1344 and applicable federal regulations. History Note. Authority G.S. 143-215.3(a)(1); 143-215.3(c); 143B-282(1)(u), RRC Objection Eff. July 18, 1996 due to lack of statutory authority and ambiguity; Eff. October 1, 1996. .0507 ISSUANCE OF CERTIFICATION (a) Time Limit for Final Action on Certification Application. All applications for certification shall be granted or denied within 60 days after receipt at the offices of the Director in Raleigh, North Carolina. Failure to take final action within 60 days shall result in a waiver of the certification requirement by the Director, unless: (1) The applicant agrees, in writing, to a longer period; (2) Final decision is to be made pursuant to a public hearing; (3) Applicant fails to furnish information necessary to the Director's decision; (4) Applicant refuses the staff access to its records or premises for the purpose of gathering information necessary to the Director's decision or; (5) Information necessary to the Director's decision is unavailable. (b) Tmie Limit for Final Action on Certification Application After Hearing. All applications for certification shall be granted or denied within 60 days after public hearing. Failure to take final action within 60 days shall result in a waiver of the certification requirement by the Director unless the applicant otherwise agrees in writing, or unless Subparagraph (a)(3), (4), or (5) of this Rule shall apply. (c) Conditions of Certification. Any certification issued pursuant to this Rule may contain such conditions as the Director shall deem necessary to insure compliance with Sections 301, 302, 303, 306, and 307 of the Federal Water Pollution Control Act Amendments. (d) Modification or Revocation of Certification (1) Any certification issued pursuant to this Rule shall be subject to revocation or modification for violation of conditions of 301, 302, 303, 306, and 307 of the Federal Water Pollution Control Act Amendments. (2) Any certification issued pursuant to this Rule shall be subject to revocation or modification upon a determination that information contained in the application or presented in support thereof is incorrect or NORTH CAROLINA ADMINISTRATIVE CODE 10115196 Page 5 EHNR - ENVIRONMENTAL MANAGEMENT TISA: 02H.0500 if conditions under which the certification was made have changed. (e) Notification of Unapproved Application. In the event that the Director denies the application for certification or for any reason is unable to approve the application, the Director shall so notify the applicant by certified or registered mail, return receipt requested, specifying in such notification the reasons for the denial or inability to approve; and a copy of the notification shall be mailed to the appropriate federal licensing or permitting agency and EPA. History Note: Statutory Authority G.S. 143-215.3(a)(1); 143-215.3(c); 143B-282(1)(u); Eff. February 1, 1976; Amended Eff.. July 1, 1988; December 1, 1984; RRC Objection E„8`: July 18, 1996 due to lack of statutory authority and ambiguity, Recodifed from 15A NCAC 2H .0504 Eff. October 1, 1996; Amended Eff. October 1, 1996. 1000 copies of this document were printed at a cost of $ 181.80 or $ .18 per copy . V NORTH CAROLINA ADMINISTRATIVE CODE 10115196 Page 6 i f;?.-; ;? y ' ?f ? . i I i_.., ?:. ii ?Y , ,,{ aJ 'I ??:> Baker and Associates A Unit of Michael Baker Corporation 200 CentrePort Drive, Suite 225 Greensboro, NC 27409 (336) 931-1500 FAX (336) 931-1501 February 13, 2003 Mr. Todd St. John, P.E. North Carolina Division of Water Quality 1650 Mail Service Center Raleigh, NC 27699-1650 f L t k t Subject: Stormwater Management Plan Piedmont Triad International Airport Dear Mr. St. John: Baker and Associates (Baker) has been in contact with you over the past two years regarding the Stormwater Management Plan for the Piedmont Triad Airport Authority (PTAA) and the 401 Water Quality Permit. Previous correspondence during the 2001 calendar year dated August 22, September 12, October 9 and the most recent correspondence dated March 5, 2002 addressed water quality issues relating to the operation of the proposed stormwater management ponds for the future development a the Piedmont Triad International Airport The subject of these past discussions was the operation of the ponds as they relate to the removal of Total Suspended Solids (TSS). As you are aware, the proposed stormwater management ponds have been designated as dry detention ponds and the published TSS removal rate for dry ponds is 50 percent. It is understood that additional measures are to be put in place in order to reach the Division of Water Quality's goal of 85 percent removal of TSS prior to the runoff entering Brush Creek. The March 5, 2002 letter as authored by Baker identified a plan to strive toward reaching the 85 percent TSS removal goal. In March 2002, the design of the ponds had not started and the level of detail that is desired by your office for review and comment was not available. Attached are the final grading and pond configuration drawings of the three proposed dry ponds. The ponds will operate in the following manner: • The runoff from the one inch storm will be contained in each pond to the elevation of the principal riser • The one inch storm - temporary water quality storage volume - will discharge over a four day period through a dewatering orifice • The principal spillway will discharge into an energy dissipator and then into the level spreaders under low flow conditions. • The ten year storm event will discharge through the principal spillway • The one hundred year storm will discharge through a combination of the principal spillway and the emergency spillway Level spreaders will be constructed at the outfall of the energy dissipators that control the flow from the principal spillways. These level spreaders have a minimum bottom width of one foot with maximum bottom width of 5 feet. The level spreaders are designed that the crest elevation of the spreader is undisturbed ground at a constant elevation. These level spreaders have been sized in accordance with the level spreader design options as published by the DWQ which is the option to discharge the one-inch rainfall at a maximum of one cubic foot per second per one hundred feet of level spreader for forested areas. The following is a summary of the level spreader design: • Pond F-1- discharge rate of 1.65 cubic feet per second - the proposed length of level spreader is 210 linear feet. Crest elevation 805. • Pond F-2 - discharge rate of 1.71 cubic feet per second - the proposed length of level spreader is 275 linear feet. Crest elevation 804. • Pond F-3 - discharge rate of 1.30 cubic feet per second - the proposed length of level spreader is 215 linear feet. Crest elevation 810. The level spreaders have been proposed to the maximum extent possible in order to provide as much time as possible for the settling of suspended solids prior to the runoff entering the buffer. Attached are the calculations for the peak discharge through the dewatering orfices into the level spreader. The water quality system is comprised of four components that operate in series to remove TSS prior to the runoff entering Brush Creek. This system utilizes the existing natural system in combination with the construction of sediment removal tools as defined in the Best Management Practices manual. Table Number 1 reflects the combination of the TSS removal percentages for each Best Management Practice (BMP) structure that is proposed for the ultimate build out of the site. Should you require any additional information regarding the efficiency of the proposed water quality controls for the development of the site, please contact this office at any time. Sincerely, PA?KER AND ASSOCIATES Wan R. Berenbro ,k Project Manager Attachments Table 1 Pond Drawings SG 10 and SG 11 Dewatering Orifice Spreadsheet cc: Mickie Elmore (w/aft) Bill Cooke (w/att) orifice equation Dewaterin Orifices for Ponds F-1, F-2 and F-3 orifice equation calculat ions Q=ca 2 h ^.5 pipe diame ter C= 0.6 h= top of grate - pipe centerline 9= 32.2 tructure diameter of dewatering orifice (inches) diameter of dewatering orifice (feet) (ft^2 Crest of Principal Spillway / Temporary Water Quality Storage Elevation invert of dewatering orifice Maximum Head (feet) Q Maximum Dewatering Discharge (CFS) Principal Riser F-1 5 0.42 0.14 817.25 810.75 6.29 1.65 F-2 5 0.42 0.14 817.25 810.25 6.79 1.71 F-3 5 0.42 0.14 826.3 821.59 4.50 1.39 Page 1 H M d r d a z o 'H" z z z ? Ct ?C r y ?Yp? OY ? 7yC? ? ""'3 J row CrJCl7M H - Hm y v m? > H ? C o ¢ V] A O 0 9 R d p roroH ' CD ?, HHOx ; a+? CD t2l x?4r? D ¢ o ? 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O O O O r? ` c) p CD CD O O rn (n CD z CD O y CD CD CD CD `C C O z D C D ? N CD 3 'i3 C cCD O ? CD ¢ C G CD O 0 • O CD 4 " CD p C) rij P. N CD 0 CD CD Q. ? (D CD C' 'D (IQ OOq to CD CD Er O 'C - G C. ? ? O O R N .O? O ? f1 ?n O ? O 7y ? ? ? O•' O F+ .? H CD O y 'W Richard L. Phillips Professional Engineer N.C. Divisiop of Water Quality ATTN: Cyndi Karoly 1650 Mail Service Center Raleigh, NC 27699-1650 RE: Fed Ex Water Quality Certification September 13, 2002 Attached are the minutes of a meeting July 17a' with the PTAA engineering staff. Please make these available to Mr. John Dorney and other decision-makers in DWQ. I talked to Mr. Dorney yesterday, and he suggested I send these in and also call for an appointment with you and possibly Mr. StJohn. To me, the minutes reflect the current thinking on the part of the Airport Authority. Because I am concerned with their approach, I share these with you. These minutes were accepted by the ABEQ (Guilford Co. Advisory Board for Environmental Quality) at their August meeting. Thank you, Richard L. Phillips, P E ;rl o. of V' Construction • Erosion Control • Water J1 };? `3955 Bittle Road . SEP 1 7 2002 Gibsonville, NC 27249 Wa TLANDS (336) 698-0028 DPhillengr@aol-com 1 6 Y Quality • Constructed ? 1etlands MEETING JULY 17, 2002 ABEQ sub-committee members John Robinson, Mike Wescott, and Dick Phillips met on July 17th with PTAA engineering staff. These were Mickie Elmore, Kevin Baker, Alan Berenbrock, and Melinda King. The following is a record of items discussed plus some additional comments by sub-committee members. 1. PLAN. The PLAN (Stormwater Management Plan) is an "ongoing document, subject to change as new information becomes available." It is "conceptual", containing examples and location and examples of ponds. It is "subject to change as new information becomes available." 2. OBJECTIVES. Mr. Ellmore stated that PTAA is committed to protecting our water quality, following the most stringent of State or County requirements, and assured us "that a dam safety permit will be secured if needed." In addition to water quality protection, their objective is to limit post-development flow to pre-development flow for the 10 year storm, release the one inch storm runoff over 4-6 days (Guilford Co. regs), and pass the 100 year storm through the emergency spillway. 3. GRADING PLAN. Baker &Associates are working on the final grading plan at this time, and expect it to be done in late 2002. They are planning the F series of ponds also and will check with ABEQ at the 50 or 75% point of completion. 4. TEMPORARY STORAGE. A considerable amount of time was spent discussing the design of the F series ponds. They appear to be very short of the required temporary storage needed (probably less than half that required) when the 10 year storm occurs. With the present plan, flow would occur through the emergency spillway when this storm occurs, thus they would not meet the 10 year criteria. It was agreed that Alan would re-examine the model, then contact Dick Phillips. The discrepancies may be due to the model used, the mixing of the Rational Formula with some type of hydrograph, and the routing technique. A suggestion was made that perhaps too much information is provided in the Plan, and this should be for internal use only. This was countered by the fact that the Plan is a public document and is the basis for the 401 permit and for future consulting contracts. Thus it needs to be based on correct hydraulics and hydrology, even though it is a "document in progress." 5. DAM SAFETY PERMIT. The reason that consideration of a dam safety permit is so critical in the planning stage is that it will affect the size and the location of all structures, particularly the F series. ABEQ's calculations show that the present F series ponds already require a permit, even though the PLAN shows lightly less than 10 acre feet to the emergency spillway. When the additional storage is provided to pass the 10 year storm, this undoubtedly will increase the storage far belong the 10 acre feet. ADDITIONALLY, North Carolina requires the storage measured to top of dam, not emergency spillway as shown in the Plan. The F series ponds are really major structures, and sub-committee members were pleased that they are being designed as part of the grading plan at this time. « f K.. 6. OTHER DETENTION PONDS. It was the general consensus that the remaining detention ponds are not as critical as the F series, and probably can be left to consultants to design in the future. ABEQ's review show these to also be deficient in temporary storage and this should be addressed now along with the review of the F ponds.. The sub-committee was disappointed to learn that the remaining "may also become dry ponds." 7. EMERGENCY SPILLWAY DESIGN. There was a length discussion of the "C" values for emergency spillway flow. Different values can be obtained, depending on the source, ranging from 2.63 to 3.00. ABEQ's position is that water surface profiles should be used to determine correct flow (or tables incorporating this). Mike W. offered a technique, which could be used. ABEQ reluctantly agreed to use a C of 3.0, currently acceptable to Guilford County. Dick Phillips for the record stated that "It is not adequate engineering design for these major structures to simply drop the flow over a low point on the dam and release over the downstream slope." All agreed. The magnitude of flow from 240 acres of impervious areas during the 100 year storm should be noted. This is in the order of 145 acre feet, almost 900 of which will flow through the emergency spillway(s). Further restrictions will be added to the design since these will undoubtedly require a dam safety permit and State review. It is quite possible some type of reinforced concrete spillway will be required, particularly considering the limited space between the F structures and the jurisdictional wetlands. The use of riprapped emergency spillways for this type of flow was seriously questioned by Phillips. 8. WATER QUALITY. Water quality was discussed at length, particularly with the F series ponds. The majority of ABEQ members do not believe that the proposals in the PLAN go far enough in reducing pollutants, that is they are not the "Best Available Technology." Also ABEQ does not accept as adequate the minimum State standard of 85% removal of TSS (total suspended solids) considering the proximity of the pollution source to municipal water supplies. It is ABEQ's belief that either (1) wet detention ponds should be used, or (2) extended dry detention ponds with further treatment in existing wetlands or preferably constructed wetlands.. 9. WETLAND USE. The efficient use of existing wetlands poses a very difficult task for the F structures, as three things are required for treatment: (1)Sheet flow, (2) very slow velocity, less than 2 fps, and (3) several days of detention time, 14 days being the preferred. Conveying flow from the detention structures to the wetlands will be a major challenge, and use of "grass swales and level spreaders at 150 feet" below principal spillway pipes will not be adequate according to Phillips, and will be a continual maintenance headache in order to secure treatment. The use of a separate piping system to distribute the one inch of temporary water quality storage was discussed, particularly the use of distribution pipes separate and apart from the principal spillway. Several suggestions were given. Mr. Wescott's experience with the detention ponds at Oak Hollow Mall can be very useful. 10. PLAN CHANGES. The present PLAN is being reviewed by a number of regulatory agencies, and ABEQ's position is that if DWQ approves the plan as presently written as to structure size and location and use or non-use of wetlands, this locks the PTAA into the plan as presented. For example, if the present wet detention ponds alongside the new runway were to be changed later to dry ponds, this would be a violation of the PLAN, and not in keeping with a 401 water quality certification. If it is anticipated that if changes are necessary, they should be made at this time and DWQ notified. ABEQ's position is that in keeping with (8) above, that there are two solutions-- either wet detention ponds, or extended dry detention ponds followed by flow through wetlands. If wetlands downstream of the ponds are not feasible, then this alternative is no longer feasible. In any event, ABEQ believes that the PLAN sets the design of all these structures, and there is no leeway once the 401 permit is issued based on a precise PLAN, which DWQ has reviewed and accepted. 11. SUMMARY. The meeting was cordial and appreciated by ABEQ sub- committee members and they look forward to further contact to address a number of questions. The bottom line is that a number of decisions by regulatory agencies are ongoing, all based on the current PLAN. For this reason we believe the PLAN should reflect any changes under consideration, and DWQ should be notified of pending changes so these can be considered in their deliberations, all before the 401 water quality certification is issued. . 1 00 Richard L. Phillips Professional Engineer N.C. Division of Water Quality ATTN: Cyndi Karoly 1650 Mail Service Center Raleigh, NC 27699-1650 RE: Fed Ex Water Quality Certification U 3955 Bittle Road Gibsonville, NC 27249 (336) 698-0028 DPhillengr@aol.com September 13, 2002 Attached are the minutes of a meeting July 17th with the PTAA engineering staff. Please make these available to Mr. John Dorney and other decision-makers in DWQ. I talked to Mr. Dorney yesterday, and he suggested I send these in and also call for an appointment with you and possibly Mr. StJohn. To me, the minutes reflect the current thinking on the part of the Airport Authority. Because I am concerned with their approach, I share these with you. These minutes were accepted by the ABEQ (Guilford Co. Advisory Board for Environmental Quality) at their August meeting. Thank you, Richard L. Phillips, P E Construction e Erosion Control • Water Quality • Constructed Wetlands MEETING JULY 17, 2002 ABEQ sub-committee members John Robinson, Mike Westcott, and Dick Phillips met on July 17th with PTAA engineering staff. These were Mickie Elmore, Kevin Baker, Allan Berenbrok, and Melinda King. The following is a record of items discussed plus some additional comments by sub-committee members. 1. PLAN. The PLAN (Stormwater Management Plan) is an "ongoing document, subject to change as new information becomes available." It is "conceptual", containing location and examples of ponds. 2. OBJECTIVES. Mr. Ellmore stated that PTAA is committed to protecting our water quality, following the most stringent of State or County requirements, and assured us "that a dam safety permit will be secured if needed." In addition to water quality protection, their objective is to limit post-development flow to pre-development flow for the 10 and the 2 year storms, release the one inch storm runoff over 2-5 days and pass the 100 year storm through the emergency spillway. Note: Guilford Co. regs are 4-6 days and ABEQ's position has always been 8-10 days for the release rate, and limit post-development flow for the 25 year storm, see Position Statement of 5-12-99, and subsequent statements. 3. GRADING PLAN. Baker &Associates are working on the final grading plan at this time, and expect it to be done in late 2002. They are planning the F series of ponds also and will check with the sub- committee at the 50 or 75% point of completion. 4. TEMPORARY STORAGE. A considerable amount of time was spent discussing the design of the F series ponds. They appear to be very short of the required temporary storage needed (probably less than half that required) when the 10 year storm occurs. With the present plan, flow would occur through the emergency spillway when this storm occurs, thus they would not meet the 10 year criteria. It was agreed that Alan would re-examine the model, then contact Dick Phillips. The discrepancies may be due to the model used, the mixing of the Rational Formula with some type of hydrograph, and the routing technique. A suggestion was made that perhaps too much information is provided in the Plan, and this should be for internal use only. This was countered by the fact that the Plan is a public document and is the basis for the 401 permit and for future consulting contracts. Thus it needs to be based on correct hydraulics and hydrology, even though it is a "document in progress." 5. DAM SAFETY PERMIT. The reason that consideration of a dam safety permit is so critical in the planning stage is that it will affect the size and the location of all structures, particularly the F series. ABEQ's calculations show that the present F series ponds already require a permit, even though the PLAN shows lightly less than 10 acre feet to the emergency spillway. When the additional storage is provided to pass the 10 year storm, this undoubtedly will increase the storage far belong the 10 acre feet. ADDITIONALLY, North Carolina requires the storage measured to top of dam, not the emergency spillway level as shown in the Plan. The F series ponds are really major structures., and sub-committee members were pleased that they are being designed as part of the grading plan at this time. , ,,,. K 6. OTHER DETENTION PONDS. It was the general consensus that the remaining detention ponds are not as critical as the F series, and probably can be left to consultants to design in the future. ABEQ's review show these to also be deficient in temporary storage and this should be addressed now along with the review of the F ponds. The sub-committee was disappointed to learn that the remaining "may also become dry ponds." 4` 7. EMERGENCY SPILLWAY DESIGN. There was a lengthy discussion of the "C" values for emergency spillway flow. Different values can be obtained, depending on the source, ranging from 2.63 to 3.00. Phillips' position is that water surface profiles should be used to determine correct flow (or tables developed from these). Mike W. offered a technique, which could be used. The sub-committee reluctantly agreed to use a C of 3.0, currently acceptable to Guilford County. Dick Phillips for the record stated that "It is not adequate engineering design for these major structures to simply drop the flow over a low point on the dam and release over the downstream slope." All agreed. The magnitude of flow from 240 acres of impervious areas during the 100 year storm should be noted. This is in the order of 145 acre feet, almost 90% of which will flow through the emergency spillway(s). Further restrictions will be added to the design since these will undoubtedly require a dam safety permit and State approval. It is quite possible some type of reinforced concrete spillway will be required, particularly considering the limited space between the F structures and the jurisdictional wetlands. The use of riprapped emergency spillways for this type of flow was seriously questioned by Phillips. 8. WATER QUALITY. Water quality was discussed at length, particularly with the F series ponds. The majority of ABEQ members do not believe that the proposals in the PLAN go far enough in reducing pollutants, that is they are not the "Best Available Technology." Also the sub- committee does not accept as adequate the minimum State standard of 85% removal of TSS (total suspended solids) considering the proximity of the pollution source to municipal water supplies. It is ABEQ's belief that either (1) wet detention ponds should be used, or (2) extended dry detention ponds with further treatment in existing wetlands or (preferably) constructed wetlands. (Refer to previous ABEQ position statements.) 9. WETLAND USE. The efficient use of existing wetlands poses a very difficult task for the F structures, as three things are required for treatment: (1)Sheet flow, (2) very slow velocity, less than 2 fps, and (3) several days of detention time, 14 days preferred. Conveying flow from the detention structures to the wetlands will be a major challenge, and use of "grass swales and level spreaders at 150 feet" below principal spillway pipes will not be adequate according to Phillips, and will be a continual maintenance headache in order to secure treatment. The use of a separate piping system to distribute the temporary water quality storage was discussed, particularly the use of distribution pipes separate and apart from the principal spillway. Several suggestions were given. Mr. Westcott's experience with the detention ponds at Oak Hollow Mall can be very useful. 10. PLAN CHANGES. The present PLAN is being reviewed by a number of regulatory agencies, and the sub-committee's position is that if DWQ approves the plan as presently written as to structure size and location and use or non-use of wetlands, this locks the PTAA into the plan as presented. For example, if the present wet detention ponds alongside the new runway were to be changed later to dry ponds, this would be a violation of the PLAN, and not in keeping with a 401 water quality certification. If it is anticipated that if changes are necessary, they should be made at this time and DWQ notified. If wetlands downstream of the ponds are not feasible, then the alternative of dry ponds only is no longer feasible. In any event, the sub- committee believes that the PLAN sets the location and type of these structures, and there will be no leeway once the 401 permit is issued based on the PLAN as submitted to DWQ (which they will review and accept as part of their approval process.) 11. SUMMARY. The meeting was cordial and appreciated by ABEQ sub- committee members and they look forward to further contact to address a number of questions. The bottom line is that a number of decisions by regulatory agencies are ongoing, all based on the current PLAN. For this reason we believe the PLAN should reflect any changes under consideration, and DWQ should be notified of pending changes so these can be considered in their deliberations, all before the 401 water quality certification is issued. 4 Post Office Box 3427 Greensboro, N.C. 27402 (336) 373-3334 Guilford County ADVISORY BOARD FOR ENv'VIRONTMENTAL QUALITY Mr. Greg Thorpe November 15, 2001 NC Department of Environment and Natural Resources Division of Water Quality 1650 Mail Service Center Raleigh, NC t7s' i- Dear Mr. Thorpe, RE: FedEx Water Quality Certification I realize the official comment period is over but I have now had the opportunity to receive and review the Stormwater Management Plan (which was not available during the comment period). Thus I offer the following for your deliberations on this project. This project has more water quality impact than any other in North Carolina and as such deserves the highest possible level of protection for our municipal water supplies. It is my opinion that the Plan does not go far enough toward this end. I base this on a review of segments of the plan which show a number of inadequacies and errors (see the attachment). I trust these will be helpful in your analysis of this project. If you would like to explore these further, I would be happy to discuss these in person at your time and convenience. My home phone is 336 698 0028. Sincerely, Richard L. Phillips, PE Member, ABEQ Attachment M CONCERNS--STORMWATER MANAGEMENT PLAN--PTAA Nov 15, 01 1. Emergency spillway flows are incorrectly calculated, ranging in an error of 67% for a 1.0 foot depth, to a 33% error for a 3.0 foot depth. As a result, the top of dam elevations are too low and should be approximately 0.5 feet higher. 2. The Plan uses orifice flow to calculate discharge through the principal spillways. This is not correct for higher stages when the control passes to pipe flow. 3. The research shows dry detention ponds to be only 30 to 35% effective in removing TSS. If dry detention ponds are used, the temporary water quality storage should be directed to a constructed wetland downstream (an extended detention wetland.) This has not been planned. 4. The use of grass waterways to achieve a 35% removal of pollutants is not supported by the literature. It is true that a vegetated filter strip using sheet flow is quite effective in removing pollutants, but the flow characteristics in a waterway are more concentrated with a higher velocity and short contact time. For this reason, the coupling of dry detention ponds with grass waterways is without a doubt insufficient to achieve a 85% removal rate. The literature would rate this combination as probably less than 50% efficient. 5. The 0.8 inches of runoff from the impervious areas should be increased to one inch. It is acknowledged that for Runoff Curve Number 98 there will be slightly less than one inch of runoff. However, a better design for a watershed which is completely impervious is to use 100% runoff. In the case of F-1 (as well as F-2 and F-3) the temporary water quality storage should be 6.67 acre feet rather than 6.33 acre feet. 6. Although the Rational Formula has been in existence for the last 100 years or so, there are recent hydrologic methods which are improved. Using the SCS (now NRCS) methodology, the peak flow for P-7 is in an additional 39%, and for F-1, an additional 17%. The second problem with the Rational Formula is that it computes only peak flows and was never intended for the design of storage and detention structures. 7. Temporary storages were computed for P-7 and F-1 using SCS TR-55 and compared to the model used in the Plan. P-7 requires 7.04 acre feet and F-1 requires 15.3 acre feet. In both cases the available storage is insufficient, providing only 56% and 48% of the required storage respectively. This would (like 41 above) raise the top of the dam 8. It appears that the planners had an overriding concern to avoid a dam safety permit from NC DENR, as this is addressed on all the design forms available. This approach limits the solution and in some cases is not the most economical. For example, the runoff from the 240 acres of impervious surfaces is presently divided into 3 sites (17- 1,2, 3). A better solution might be to use one larger structure requiring a dam safety permit and direct the temporary water quality storage to an extended detention wetland. As it is, the three structures appear to be "hung" on the side of the embankment immediately adjacent to the existing wetlands. In any event, dry detention ponds will not sufficiently remove the pollutants from 240 acres of impervious surfaces. '^ s Richard L. Phillips Professional Engineer Mr. William G. Ross, Jr. Secretary, NC DENR 1601 Mail Service Center. Raleigh, NC 27599-1601 Re: FEDEX hub, Greensboro, NC. Dear Mr. Ross, 3955 Bittle Road Gibsonville, NC 27249 (336) 698-0028 DPhillengr@aol.com June 17, 2002 This is a follow-up to Elaine Stover's letter of January 29, 2002 which expresses the opinion that the Piedmont Triad Airport Authority has not demonstrated that they will adequately protect the water supplies of Greensboro with the best available technology. It is directed to you since it involves two Divisions in your Department. In addition to the water quality issues listed in that letter, I have additional concerns which warrant your consideration. 1. The Airport Authority has shown an overriding desire to avoid any future review by your Department, as they repeatedly state in their documents that none of their ponds will require a dam safety permit as all have been sized below the 10 acre feet requirement. 2. There are a number of design deficiencies in the hydraulics and hydrology of detention dams shown in the Stormwater Management Plan with the result that only about half of the required storage has been provided. Details of this are provided in an attached letter written November 15th '2001 to Mr. Greg Thorpe, Division of Water Quality. 3. Once DENR grants the 401 Water Quality Certification, the Airport Authority is no longer subject to any oversight by your Department as "The PTAA is considered a local authority permitted by NCDENR to develop its own stormwater ordinances..." The end result of all this is that there seems to be a determined effort to avoid any oversight by your Department after the 401 Water Quality Certification is granted. As a result water quality will be diminished. For this reason, I suggest you ask the Dam Safety personnel in the Division of Land Quality to: (1) review Sites F-1 and P-7 to see if they meet the 24 hour-25 year criteria (2)determine if they are governed by the Dam Safety Law of 1967 (as amended). I know your staff is busy, but I believe this action would be in the best interests of all citizens of Guilford County as well as the State of North Carolina. May I please have eply at your earliest convenience? Sincerely, f Richard L. Phillips Attach: Nov. 15, 01 letter to Greg Thorpe January 29, 02 letter to William Ross,.Jr. Construction • Erosion Control Water Quality 0 Constructed Wetlands July 11, 2002 ABEQ Meeting. Questions from ABEQ to PTIA officials - Mickie Elmore, Kevin Baker and Alan Berenbrock. Questions in italics, answers in regular font. 1. We in ABEQ have been asking for details for the last two years as to specific designs of the detention ponds, starting with our letter of July 24, 1999. Is the Stormwater Management Plan finalized? Our copy is a preliminary final one dated April, 2001, and is of a conceptual nature. The document is not finished. Completed, as is, in April 2001. It is a work in progress. Randleman rules have been adopted. All BMP structures are conceptual in nature. 2. Is there a grading plan for the new runway sorting facility, taxiways, etc.? Does it include any of the detention ponds, particularly the F series? We note the precision of the 1,174, 174,582 cubic yards of fill discharged into jurisdictional wetlands, thus believe grading plans do exist. The F series structures are major structures and are of such importance that they justify detailed planning, and without this type of planning we cannot analyze them. Agree that F series ponds are important. None. Have been designed. Fill numbers are preliminary and subject to change. New grading plan due in October. A copy will be sent to ABEQ when it is completed. 3. Do you have specific plans for the F series (a) limiting flow to the existing wetlands, thus increasing detention time, (b) providing sheet flow through the wetlands, (c) limiting velocity to one or two feet per second through the wetlands? We have guidelines but not specific plans. The space for ponds is very tight. The document was written to meet or exceed current city, state, county guidelines.- 4. Will the ou flow from the larger storms, like the 10 and 100 year, also flow through the existing wetlands? Yes. 5. How do you propose to remove soluble pollutants, lead, zinc, rubber, and oil and grease in the runofffrom the impervious areas? ABEQ s position is that the removal of TSS is not enough, since this is a critical area draining immediately into a municipal water supply, and all pollutants must be addressed. Don't. Not required by state. State actually requires 85% removal of TSS. 6 Do you have a policy of complying with criteria in the Guilford County Watershed Protection Manual (January 1997)? Yes. County requirements have been adopted into Master Plan. Watershed plans can be submitted to us for review. They always meet or exceed requirements be it watershed or building plans. w . ? 7. Have you seen comments over the last year or so by ABEQ and its members directed to the NC Division of Water Quality? These are a matter of public record, but in cae you have not, we are attaching copies. Have seen the comments they work closely with NCDENR and have taken any comments into consideration. 8. It is apparent that there has been an effort to avoid a NC Dam Safety Permit. As will be noted in the attached comments, the structures are lacking in storage capacity, which compromises water quality, and fail to meet Guilford County criteria. Are we correct in this? It is our view that the runofffrom 240 acres of impervious area is so major that a dam safety permit will be necessary, particularly when the proper storage is provided. Aware of Dam Safety Laws - - Instead of 1 pond they have broken it down into 3 ponds. - They would rather have several non-high hazard dams than 1 high hazard dam. - There is a document in master plan that asks designer of pond "is a dam safety permit required" if so it is obtained. - Ponds might be use specific (i.e. runoff from plane maintenance areas goes to one pond, runways go to another pond. - -Airport is in the process of obtaining a NPDES permit. Plans due in October will have pond design information. NPDES permits will include soluble pollutants and give corrective activities should pollutant levels exceed those allowed by the permit.