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HomeMy WebLinkAboutSW8050547_Historical File_20201006ROY COOPER Governor MICHAEL S. REGAN Secretary BRIAN WRENN October 6, 2020 NORTH CAROLINA Envimnmaud Quality New Hanover County Airport Authority Attn: Granseur Dick, Facilities Director 1740 Airport Boulevard, Suite 12 Wilmington, NC 2.8405 Subject: State Stormwater Management Permit No. SW8 050547 Wilmington International Airport EDDB High Density Project New Hanover County Dear Mr. Dick: The Wihmington Regional Office received a complete, iriodified State Stormwater Management Permit Application for the subject project on October 5, 2020. Staff review of the plans and specifications has determined that the project, as proposed, complies with the Stormwater Regulations set forth in Title 15A NCAC 02H.1000 (1995 Rules) and subsequently amended on January 1, 2017 (2017 Rules). We are hereby forwarding modified Permit No. SW8 050547 dated October 6, 2020, for the construction of the built -upon areas (BUA) and stormwater control measures (SCMs) associated with the subject project. This permit shall be effective from the date of issuance until June 15, 2027 and the project shall be subject to the conditions and limitations as specified therein and does not supersede any other agency permit that may be required. Failure to comply with these requirements will result in future compliance problems. Please note that this permit is not transferable except after notice to and approval by the Division. Please refer to Attachment C for a detailed description of the current proposed major modification and a list of all The past modifications approved during the effective period of the permit. This cover letter, attachments, and all documents on file with DEMLR shall be considered part of this permit and is herein incorporated by reference. Please add the attached plans to the previously approved plan set. Please replace the previous application (SWU-101), supplement, operation and maintenance agreement with the attached modified versions. If any parts, requirements, or limitations contained in this permit are unacceptable, you have the right to request an adjudicatory hearing by filing a written petition with the Office of Administrative Hearings (OAH). The written petition must conform to Chapter I SOB of the North Carolina General Statutes and must be filed with the OAH within thirty (30) days of receipt of this permit You should contact the OAH with all questions regarding the filing fee (if a filing fee is required) and/or the details of the filing process at 6714 Mail Service Center, Raleigh, NC 27699-6714, or via telephone at 919-431-3000, or visit their website at www.NCOAH.com. Unless such demands are made this permit shall be final and binding. If you have any questions concerning this permit, please contact Garrett Zorda in the Wilmington Regional Office, at (910) 796-7215 or garrett.zorda@ncdenr.gov. Sincerely, Brian Wrenn, Director Division of Energy,. Mineral and Land Resources Enclosures: Attachment A — Designer's Certification Form Attachment C — Permitting History\ Application Documents DES/gdz:%StormwaterTermits & Projects\2005\050547 HD\2020 10 permit 050547 North Carolina Department of Environmental Quality 1 Division of Energy, Mineral and land Resources rma-+.cROUNA 4F, E Wilmington Regional Office 1 l27 Cardinal Drive Extension Wilmington, North Carolina 284405 a0ffk. dbvb.—mmw a.tlbCnn7QA7775 State Stormwater Permit No. SW8 050547 Page 2 of 2 cc: Ramon Marconi, PE, Talbert & Bright, Inc. New Hanover County Building Safety Department. Wilmington Regional Office Stormwater File State Stormwater Management Systems Permit No. SW8 050547 STATE OF NORTH CAROLINA DEPARTMENT OF ENVIRONMENTAL RESOURCES DIVISION OF ENERGY, MINERAL AND LAND RESOURCES STATE STORMWATER MANAGEMENT PERMIT HIGH DENSITY DEVELOPMENT In accordance with the provisions of Article 21 of Chapter 143, General Statutes of North Carolina as amended, and other applicable Laws, Rules, and Regulations PERMISSION IS HEREBY GRANTED TO New Hanover County Airport Authority Wilmington International Airport Extended Dry Detention Basin No. 1 1740 Airport Boulevard, Wilmington, New Hanover County FOR THE construction, operation and maintenance of an extended dry detention basin in compliance with the provisions of 15A NCAC 2H .1000 (hereafter collectively referred to as the "stormwaterrules') and the approved stormwater management plans and specifications and other supporting data as attached and on file with and approved by the Division of Energy, Mineral and Land Resources (the "Division" or "DEMLR") and considered an enforceable part of this permit. This permit shall be effective from the date of issuance until June 15, 2027, and shall be subject to the following specified conditions and limitations: I. DESIGN STANDARDS 1. This permit is effective only with respect to the nature and volume of stormwater described in the application and other supporting data. 2. This stormwater system has been approved for the management of stormwater runoff as described in Section 1.7 of this permit. The "Phase I and II" stormwater control is an extended dry detention basin that has been designed to handle the runoff from 8,520,835 square feet of impervious area, including 2,223,812 sf. of future allocation, within a drainage area of 287.63 acres (12,529,107 sf). The "Overall" condition of the dry detention basin has been designed to handle the runoff from 9,751,185 square feet of impervious area, including 3,454,162 sf. of future allocation, within a drainage area of 322.34 acres (14,041,075 sf). 3. The tract will be limited to the amount of built -upon area indicated in Section 1.7 of this permit, and per the application, the approved plans, calculations and other supporting documentation. 4. Where an individual project within the drainage area is being leased or sold, the stormwater collection system for that project must be located in either dedicated common areas or easements and the final plats will be recorded showing all such required easements. 5. The runoff from all built -upon area within the permitted drainage area of this project must be directed into the permitted stormwater control system. 6. All development projects within the permitted contributing drainage area of the extended dry detention basin BMP must submit plans to the Division for review and approval prior to construction. Depending on ownership, a permit modification may or may not be required. Page 1 of 4 State Stormwater Management Systems Permit No. SW8 050547 7. That portion of the existing airport previously included in the drainage area of the permitted dry detention basin that is being removed, must be submitted in a future permit application as a modification or under Session Law 2012-200. 8. The following design criteria have been provided and must be maintained in the "Phase I and II" extended dry detention basin and in the "Overall" extended dry detention basin. Phase I & II Overall a. Drainage Area, acres: 287.63 322.38 Onsite, ft2: 12,529,107 14,041,075 Offsite, ft2: 0 0 b. Total Impervious Surfaces, ft2: 8,520,835 9,751,185 C. Design Storm, inches: 4,552,087 @1" 4,552,087 @1 ' 3,968,748 @1.5" 5,199,098 @1.5" d. Basin Bottom Elevation, feet: 7.0 7.0 e. TSS removal efficiency: 50% 50% f. Storage Elevation, FMSL: 13.0 13.3 g. Storage Surface Area, ft2: 506,082 602,325 h. Permitted Detention Volume, ft3: 1,058,112 1,274,829 i. Seasonal High Water Table, FMSL: 6.0 6.0 j. Controlling Orifice: 12.0" 0 12.0"0 k. Drawdown Time for 12.0" 0 orifice, hours: 57 64 I. Receiving Stream/River Basin: Smith Creek / Cape Fear M. Stream Index Number: 18-74-63 n. Classification of Water Body: "C. Sw" 9. Tributary projects outside of the drainage area of the 2 "for -credit" grassed swales, but inside the drainage area of the dry detention basin, must provide an additional BMP with a sufficient TSS removal efficiency such that the total TSS removal, including the extended dry detention basin, is at least 85%. 10. FAA requirements prohibit standing water (i.e., permanent pools) and stipulate that the design storm must be fully drained within 48 hours. The approved BMP design includes a low flow device but does not include a permanent pool at the low flow outlet or sediment storage below the low flow outlet. 11. The "Phase I and II" condition will be the "permitted condition" until such time as a project within the drainage area is proposed which shall cause the permitted maximum amounts of drainage area and/or BUA for the Phase I & I I condition to be exceeded. Prior to construction of that project, the "Overall" condition must be constructed and will become the permitted condition. II. SCHEDULE OF COMPLIANCE The stormwater management system shall be constructed in its entirety, vegetated and operational for its intended use prior to the construction of any built -upon surface. The Phase & II condition. 2. During construction, erosion shall be kept to a minimum and any eroded areas of the system will be repaired immediately. 3. The facilities shall be constructed, operated and maintained in accordance with the provisions of this permit, the approved plans and specifications, and the supporting documents attached to this permit and on file with the Division. 4. Upon completion of construction, prior to issuance of a Certificate of Occupancy, and prior to operation of this permitted facility, a certification must be received from an appropriate designer for the system installed certifying that the permitted facility has been installed in accordance with this permit, the approved plans and specifications, and other supporting documentation. Any deviations from the approved plans and specifications must be noted on the Certification. A modification may be required for those deviations. Page 2 of 4 State Stormwater Management Systems Permit No. SW8 050547 5. The permittee shall at all times provide the operation and maintenance necessary to assure the permitted stormwater system functions at the design condition. The approved Operation and Maintenance Plan must be followed in its entirety and maintenance must occur at the scheduled intervals including, but not limited to: a. Semiannual scheduled inspections (every 6 months). b. Sediment removal. C. Mowing and revegetation of slopes and the vegetated filter. d. Immediate repair of eroded areas. e. Maintenance of all slopes in accordance with approved plans and specifications. f. Debris removal and unclogging of outlet structure, orifice device, flow spreader, catch basins and piping. g. Access to the outlet structure must be available at all times. 6. Records of maintenance activities must be kept and made available upon request to authorized personnel of DEMLR. The records will indicate the date, activity, name of person performing the work and what actions were taken. 7. If the stormwater system was used as an Erosion Control device, it must be restored to design condition prior to operation as a stormwater treatment device, and prior to occupancy of the facility. 8. Access to the permitted stormwater facilities shall be maintained via appropriate easements (as required) at all times. 9. No person or entity, including the permittee, shall alter any component shown in the approved plans and specifications. Prior to the construction of any modification to the approved plans, the permittee shall submit to the Director, and shall have received approval for modified plans, specifications, and calculations including, but not limited to, those listed below. For changes to the project or SCM that impact the certifications, a new or updated certification(s), as applicable, will be required and a copy must be submitted to the appropriate DEQ regional office upon completion of the modification. a. Any modification to the approved plans and specifications, regardless of size including the SCM(s), BUA, details, etc. b. Redesign or addition to the approved amount of BUA or to the drainage area. C. Further development, subdivision, acquisition, lease or sale of any, all or part of the project and/or property area as reported in the approved plans and specifications. d. Altering, modifying, removing, relocating, redirecting, regrading, or resizing of any component of the approved SCM(s), the stormwater collection system and/or vegetative conveyance shown on the approved plan. e. The construction of any allocated future BUA. f. The construction of any permeable pavement, #57 stone area, public trails, or landscaping material to be considered a permeable surface that were not included in the approved plans and specifications. g. Other modifications as determined by the Director. 10. The Director may notify the permittee when the permitted site does not meet one or more of the minimum requirements of the permit. Within the time frame specified in the notice, the permittee shall submit a written time schedule to the Director for modifying the site to meet minimum requirements. The permittee shall provide copies of revised plans and certification in writing to the Director that the changes have been made. III. GENERAL CONDITIONS The issuance of this permit does not preclude the Permittee from complying with any and all statutes, rules, regulations, or ordinances, which may be imposed by other government agencies (local, state, and federal) having jurisdiction Page 3 of 4 State Stormwater Management Systems Permit No. SW8 050547 2. This permit is not transferable to any person or entity except after notice to and approval by the Director. The permittee shall submit a completed and signed "Permit Transfer Application Form" (available on the Division website) accompanied by the required fee and supporting documentation as listed on the form, to the Division at least 60 days prior to any one or more of the following events: a. The sale or conveyance of the project area in whole or in part, except in the case of an individual lot sale that is made subject to the recorded deed restrictions and protective covenants; b. Dissolution of the partnership, corporate, or LLC entity, subject to NCGS 55-14-05 or NCGS 57D-6-07 and 08; c. Bankruptcy; d. Foreclosure, subject to the requirements of Session Law 2013-121; 3. Any individual or entity found to be in noncompliance with the provisions of this stormwater management permit or the requirements of the Stormwater rules is subject to enforcement procedures as set forth in NCGS 143 Article 21. 4. In the event that the facilities fail to perform satisfactorily the Permittee shall take immediate corrective action, including those as may be required by this Division, such as the construction of additional or replacement stormwater management systems. 5. The permittee grants DEQ Staff permission to enter the property during normal business hours for the purpose of inspecting all components of the permitted stormwater management facility. 6. The permit issued shall continue in force and effect until the permittee files a request with the Division for a permit modification, transfer, renewal, or rescission; however, these actions do not stay any permit conditions. 7. Unless specified elsewhere, permanent seeding requirements for the stormwater control must follow the guidelines established in the North Carolina Erosion and Sediment Control Planning and Design Manual. 8. Approved plans and specifications for this project are incorporated by reference and are enforceable parts of the permit. A copy of the approved plans and specifications shall be maintained on file by the Permittee at all times. 9. The permittee is responsible for compliance with all permit conditions until such time as the Division approves the transfer request. Neither the sale of the project, in whole or in part, nor the conveyance of common area to a third party constitutes an approved transfer of the stormwater permit. 10. The permittee shall submit a completed "Permit Information Update Application Form" (available on the Division website) to the Division within 30 days to making any one or more of the following changes: a. A name change of the current permittee; b. A name change of the project; c. A mailing address change of the permittee; 11. A permit renewal request must be submitted at least 180 days prior to the expiration date of this permit. The renewal request must include the appropriate application, documentation and the processing fee as outlined in Title 15A NCAC 02H.1045(3). Permit modified, updated and reissued this the 6th day of October 2020. NORTH CAROLINA ENVIRONMENTAL MANAGEMENT COMMISSION gyu,�,�- ?1 n J Brian Wrenn, Director Division of Energy, Mineral and Land Resources By Authority of the Environmental Management Commission Page 4 of 4 State Stormwater Management Systems Permit No. SW8 050547 Attachment C - Permitting History Wilmington International Airport EDDB Permit No. SW8 050547 Approval Permit RIMS Description of the Changes Date Action Version This original issuance approved the 150 acre area pocket of high density Phase I, in accordance with 6/15/2005 Original 1.0 SW8 040836, to be treated in an extended dry Approval detention basin (EDDB) #1 designed to handle the runoff from 4,247,100 square feet of impervious area. Approved the modification of the permit to include Phase II, which brought the total project area to 10/28/2009 Modification 1.1 264 acres and increased the size of the EDDB #1 to handle a total of 8,468,064 square feet of impervious area. Approved the modification to include Phase III, which brought the total project area to 321.35 acres and increased the size of the EDDB #1 to handle a 10/26/2011 Modification 1.2 total of 8,468,064 square feet of impervious area. This permit also took into account the impervious area for SW8 060326 and SW8 060515, which both drain to EDDB # 1 and were permitted as Offsite permits to SW8 050547. Approved the modification to the overall drainage area to 3 22.3 8 acres and the increased size of EDDB #1 to handle a total of 9,751,185 square feet 11/29/2012 Modification 1.3 of impervious area. This modification included the addition of two grassed pre-treatment swales. This issuance left 3,177,214 square feet of Future allocation for the Phase I & II area. Approved the reallocation of 205,202 square feet of Plan Future allocation for the development of the Rental 2/8/2013 Revision 1.4 Car Facility within the Phase I & II drainage area. This issuance left 2,972,012 square feet of Future allocation. Approved the reallocation of 32,453 square feet of Plan Future allocation for the expansion of the North 8/4/2015 Revision 1.5 General Aviation Apron draining to EDDB # 1. This issuance left 2,939,559 square feet of Future allocation for the Phase I & II area. Page 1 of 2 State Stormwater Management Systems Permit No. SW8 050547 Approved the reallocation of a total of 129,082 square feet of future allocation, 62,570 square feet Plan for the Business Park access road and 66,512 9/9/2015 Revision 1.6 square feet for Lot 9 of the Business Park, both draining to EDDB # 1. This issuance left 2,810,477 square fcct of Future allocation for the Phase I & II area. Approved the reallocation of 122,922 square feet of future allocation for the North General Aviation Hanger Taxi line and Corporate Hanger Complex. 6/29/2016 Plan 1 This also took into account the 24,190 square feet Revision '7 of impervious area allocated to SW8 150723, which drains to EDDB # 1 and is permitted as an Offsite permit to SW8 050547. This issuance left 2,663,295 square feet of Future allocation. Approved the reallocation of 75,596 square feet of 8/22/2017 Plan 1'8 future allocation for the Avis Car Rental Facility Revision draining to EDDB #1. This issuance left 2,587,699 square feet of Future allocation. Approved the reallocation of 29,337 square feet of 4/18/2018 Minor 1.9 future allocation for the Social Bark Kennel Modification draining to EDDB #1. This issuance left 2,558,362 square feet of Future allocation. Approved the reallocation of 110,358 square feet of 10/5/2018 Minor 2.0 future allocation for the FBO #2 project draining to Modification EDDB #1. This issuance left 2,448,004 square feet of Future allocation. 10/3/2019 Renewal 3.0 This issuance renewed Permit No. SW8 050547 until June 15, 2027. Approved the reallocation of 224,194 square feet of future allocation for the Air Carrier Apron Expansion draining to EDDB # 1. This modification Major also adds Pre-treatment Swale #3 as pretreatment 10/6/2020 Modification 3 .: for EDDB # 1. The submittal also included 9,268 square feet of impervious area that meets NCGS 143-214.7(c4) that does not drain to EDDB #1. This issuance left 2,223,812 square feet of Future allocation for the Phase I & 11 area. Page 2 of 2 State Stormwater Management Systems Permit No. SW8 050547 Wilmington International Airport Stormwater Permit No. SW8 050547 New Hanover County Designer's Certification I, , as a duly registered in the State of North Carolina, having been authorized to observe (periodically/ weekly/ full time) the construction of the project, (Project) for (Project Owner) hereby state that, to the best of my abilities, due care and diligence was used in the observation of the project construction such that the construction was observed to be built within substantial compliance and intent of the approved plans and specifications. The checklist of items on page 2 of this form is included in the Certification. Noted deviations from approved plans and specification: Signature Registration Number Date SEAL Page 1 of 2 State Stormwater Management Systems Permit No. SW8 050547 Certification Requirements: 1. The drainage area to the system contains approximately the permitted acreage. 2. The drainage area to the system contains no more than the permitted amount of built - upon area. 3. All the built -upon area associated with the project is graded such that the runoff drains to the system. 4. All drainage within the permitted contributing drainage area is directed into the system. 5. The outlet/bypass structure elevations are per the approved plan. 6. The outlet structure is located per the approved plans. 7. A trash rack is provided on the outlet/bypass structure. 8. All slopes are grassed with permanent vegetation. 9. Vegetated slopes are no steeper than 3:1. 10. The inlets are located per the approved plans and do not cause short-circuiting of the system. 11. The permitted amounts of surface area and/or volume have been provided. 12. Required drawdown device is correctly located and sized per the approved plans. 13. All required design depths are provided. 14. All required parts of the system are provided, such as pretreatment devices, outlet structure and/or forebay. 15. The required system dimensions are provided per the approved plans. 16. The maximum drainage area and/or built -upon area have not been exceeded for the "Phase I & II" condition. cc: NCDEQ-DEMLR Regional Office New Hanover County Building Inspections Page 2 of 2 Table in Form SWU-101, Section IV. 10. SW8 050547 Basin Information Receiving Stream Name Overall Drainage Area 1 Smith Creek Phase I & II Drainage Area Smith Creek Pretreatment Swale #3 Drainage Area Smith Creek Future Phase III Drainage Area Smith Creek Stream Class Stream Index Number C, Sw 18-74-63 C, Sw 18-74-63 C, Sw 18-74-63 C, Sw 18-74-63 Total Drainage Area (sf) On -site Drainage Area (sf) Off -site Drainage Area (sf) 14,041,075 14,041,075 0 12,529,107 12,529,107 0 696,960 696,960 0 1,511,968 1,511,968 0 Proposed Impervious Area (sf) % Impervious Area (total) 9,751,185 69.4% 8,520,835 68.0% 522,720 75.0% 1,230,350 81.4% Impervious Surface Area On -site Buildings/Lots (sf) Overall Drainage Area 1 0 Phase I & II Drainage Area 0 Pretreatment Swale #3 Drainage Area 0 Future Phase III Drainage Area 0 On -site Streets (sf) 4,252 4,252 4,252 0 On -site Parking (sf) 121,353 121,353 121,353 0 On -site Sidewalks (sf) 0 0 0 0 Other on -site (sf) 0 0 0 0 Future (sf) 3,454,162 2,223,812 298,528 1,230,350 Off -site (sf) 0 0 0 0 Existing BUA (sf) 6,171,418 6,171,418 98,587 0 Total (sf): 9,751,185 8,520,835 522,720 1,230,350 DEMLR USE ONLY Pate Received I Fee Paid Permit Number Applicablenules: ❑ Coastal SW -1995 ❑ Coastal SW - 2008 ❑ Ph II - Post Construction (select all that apply) ❑ Non -Coastal SW- HQW/ORW Waters ❑ Universal Stormwater Management Plan ❑ Other WQ Mgmt Plan: State of North Carolina Department of Environment and Natural Resources Division of Energy, Mineral and Land Resources STORMWATER MANAGEMENT PERMIT APPLICATION FORM This form may be photocopied for use as an original I. GENERAL INFORMATION 1. Project Name (subdivision, facility, or establishment name - should be consistent with project name on plans, specifications, letters, operation and maintenance agreements, etc.): Air Carrier Apron Expansion Phase I at Wilmington International Airport 2. Location of Project (street address): 1740 Airnort Boulevard City:Wilmington County:New Hanover Zip:28405 3. Directions to project (from nearest major intersection): From the Martin Luther King Blvd/US 74 exit to N. 23rd St turn left onto N 23Rd St Travel appox 0.47 miles. Turn right onto Ain2ort Boulevard Main airport entrance). Project accces is a1212ox. 0.21 miles on the right down the first gravel road (south of Gardner Road) Travel approx. 0.40 miles to project/gate entrance 4. Latitude:34° 15' 53" N Longitude:77° 54' 47" W of the main entrance to the project. II. PERMIT INFORMATION: 1. a. Specify whether project is (check one): ❑New Modification ❑ Renewal w/ Modification+ tRenewals with modifications also requires SWU-102 - Renewal Application Form b.If this application is being submitted as the result of a modification to an existing permit, list the existing permit number SW8 050547 , its issue date (if known) October 3, 2019 , and the status of construction: ❑Not Started ❑Partially Completed* ® Completed* *provide a designer's certification 2. Specify the type of project (check one): ❑Low Density ®High Density ❑Drains to an Offsite Stormwater System ❑Other 3. If this application is being submitted as the result of a previously returned application or a letter from DEMLR requesting a state stormwater management permit application, list the stormwater project number, if assigned, n/a and the previous name of the project, if different than currently proposed, n/a 4. a. Additional Project Requirements (check applicable blanks; information on required state permits can be obtained by contacting the Customer Service Center at 1-877-623-6748): ❑CAMA Major ❑NPDES Industrial Stormwater ®Sedimentation/Erosion Control: 11.0 ac of Disturbed Area 0404/401 Permit: Proposed Impacts b.If any of these permits have already been acquired please provide the Project Name, Project/Permit Number, issue date and the type of each permit:Air Carrier Apron Expansion Phase I NEWHA-2020-013 5. Is the project located within 5 miles of a public airport? ❑No ®Yes If yes, see S.L. 2012-200, Part VI: http://portal.ncdenr.org/web/Ir/rules-and-regulations APR 21 2o2o BY Form SWU-101 Version Oct. 31, 2013 Page 1 of 6 III. CONTACT INFORMATION 1. a. Print Applicant / Signing Official's name and title (specifically the developer, property owner, lessee, designated government official, individual, etc. who owns the12roject): Applicant/Organization: New Hanover County Airport Authority Signing Official & Title: Granseur Dick, PE, CM Facilities Director b. Contact information for person listed in item la above: Street Address:1740 Airport Bouleverd, Suite 12 City: Wilmington State: NC Zip: 28405 Mailing Address (if applicable): 1740 Airport Bouleverd, Suite 12 City: Wilmington State: NC Zip: 28405 Phone: (910 ) 341-4333 Fax: (910 ) 341-3465 Email: gdick@flvilm.com c. Please check the appropriate box. The applicant listed above is: ® The property owner (Skip to Contact Information, item 3a) ❑ Lessee* (Attach a copy of the lease agreement and complete Contact Information, item 2a and 2b below) ❑ Purchaser* (Attach a copy of the pending sales agreement and complete Contact Information, item 2a and 2b below) ❑ Developer* (Complete Contact Information, item 2a and 2b below.) 2. a. Print Property Owner's name and title below, if you are the lessee, purchaser or developer. (This is the person who owns the property that the project is located on): Property Owner/Organization: Signing Official & Title: b. Contact information for person listed in item 2a above: Street Address: City: Mailing Address (if applicable): City: Phone: ( ) Email: State: Zip: State: Fax: Zip: a. (Optional) Print the name and title of another contact such as the project's construction supervisor or other person who can answer questions about the project: Other Contact Person/Organization: Ramon Marconi. PE / Talbert & Bright Inc Signing Official & Title: Ramon Marconi, PE, Proiect Engineer b. Contact information for person listed in item 3a above: Mailing Address: 4810 Shelley Drive City: Wilmington State: NC Zip: 28405 Phone: (910 ) 763-5350 Fax: (910 1 762-6281 Email:rmarconi@tbiilm.com 4. Local jurisdiction for building permits: New Hanover County Point of Contact jgy Graham Phone #: (910 ) 798-7175 Form SWU-101 Version Oct. 31, 2013 Page 2 of 6 rV. PROJECT INFORMATION 1. In the space provided below, briefly summarize how the stormwater runoff will be treated. The project will be revising the drainage area to the exisiting permitted Extended Dry Detention Basin No 1 and adding an additional pretreatment swale (PreTreatment Swale #3) Project will utilize 224192 square feet of the Weviso& permited allocated built -upon area under permit SW8 050547 2. a. If claiming vested rights, identify the supporting documents provided and the date they were approved: Approval of a Site Specific Development Plan or PUD Approval Date: ❑ Valid Building Permit Issued Date: ❑ Other: Date: b. If claiming vested rights, identify the regulation(s) the project has been designed in accordance with: ® Coastal SW -1995 ❑ Ph R - Post Construction 3. Stormwater runoff from this project drains to the Cape Fear River basin. 4. Total Property Area:1620.8 acres 5. Total Coastal Wetlands Area: n/a acres 6. Total Surface Water Area: n/a acres 7. Total Property Area (4) - Total Coastal Wetlands Area (5) - Total Surface Water Area (6) = Total Project Area+:322.34 acres + Total project area shall be calculated to exclude the following: the normal pool of imimpoundedunded structures, the area between the banks of streams and rivers, the area below the Normal High Water (N11K line or Mean High Water (AffgM line, and coastal wetlands landward from the NHW (or MHM line. The resultant project area is used to calculate overall percent built upon area (BLIAA). Non -coastal wetlands landward of the NHW (or MHK) line may be included in the total project area. 8. Project percent of impervious area: (Total Impervious Area / Total Project Area) X 100 = 69.4 % 9. How many drainage areas does the project have? 1 (For high density, count 1 for each proposed engineered stormwater BMP. For low density and other projects, use 1 for the whole property area) 10. Complete the following information for each drainage area identified in Project Information item 9. If there are more than four drainage areas in the project, attach an additional sheet with the information for each area provided in the same format as below. Pretreatment Overall Phase I & II C... ,! !) Future Phase III Basin Information Drainage Area 1 Drainage Area _ Drainage Area _ Drainage Area Receiving Stream Name Smith Creek Smith Creek Smith Creek _ Smith Creek Stream Class * C, Sw C, Sw C, Sw C, Sw Stream Index Number * 18-74-63 18-74-63 18-74-63 18-74-63 Total Drainage Area (sf) 14,041,075 12,529,107 696,960 1,511,968 On -site Drainage Area (sf) 14,041,075 12,529,107 696,960 1,511,968 Off -site Drainage Area (sf) 0 0 0 0 Proposed Impervious Areas 9,751,185 8,520,835 522,720 1,230,350 Impervious Area"* total 69.4 % 68.0 % 75.0 % 81.4 % Overall Phase I P. II Pre gwnla q Fntnre Phmco U] Impervious' Surface Area Drainage Area 1 Drainage Area _ Drainage Area, Drainage Area On -site Buildings/Lots (sf) 0 0 0 _ 0 On -site Streets (sf) 4,252 4,252 4,252 0 On -site Parking (sf) 121,353 0 121,353 0 121,353 0 0 0 On -site Sidewalks (sf) Other on -site (s 0 0 0 0 Future (sf) 3,454,162 2,223,812 298,528 1,230,350 Off -site (sf) 0 0 0 0 Existing BUA*** (sf) 6,171,418 6,171,418 98,587 1 0 Total (sf): 9,751,185 8,520,835 522,720 1 1,230,350 Stream Class and Index Number can be determined at: http://portal.ncdenr.org/web/wq[ps/csu/classi cations Impervious area is defined as the built upon area including, but not limited to, buildings, roads, parking areas, sidewalks, gravel areas, etc. Form SWU-101 Version Oct. 31, 2013 Page 3 of 6 'Report only that amount of existing BUA that will remain after development. Do not report any existing BLIA that is to be removed and which will be replaced by new BUEl. 11. How was the off -site impervious area listed above determined? Provide documentation. Tributary area is entirely on -site. Proiects in Union County: Contact DEMLR Central Office staff to check if the project is located within a Threatened & Endangered Species watershed that maybe subject to more stringent stormwater requirements as per 1 SA NCAC 02B .0600. V. SUPPLEMENT AND O&M FORMS The applicable state stormwater management permit supplement and operation and maintenance (O&M) forms must be submitted for each BMP specified for this project. The latest versions of the forms can be downloaded fromhttp://portal.ncdenr.org/web/wq./ws/su/bM-manual. VI. SUBMITTAL REQUIREMENTS Only complete application packages will be accepted and reviewed by the Division of Energy, Mineral and Land Resources (DEMLR). A complete package includes all of the items listed below. A detailed application instruction sheet and BMP checklists are available from ht!p://portal.ncdenr.org/web/M/ws/su/statesw/forms does. The complete application package should be submitted to the appropriate DEMLR Office. (The appropriate office may be found by locating project on the interactive online map athttp://portal.ncdenr.org/web/wq/ws/su/maps.) Please indicate that the following required information have been provided by initialing in the space provided for each item. All original documents MUST be signed and initialed in blue ink. Download the latest versions for each submitted application package from http://portal.ncdenr.org/web/wq/ws/su/statesw/forms does. itials 1. Original and one copy of the stormwater Management Permit Application Form. 2. Original and one copy of the signed and notarized Deed Restrictions & Protective Covenants Form. (if required as per Part VII below) 3. Original of the applicable Supplement Form(s) (sealed, signed and dated) and O&M agreement(s) for each BMP. 4. Permit application processing fee of $505 payable to NCDENR. (For an Express review, refer to http://www.gnvhelp.org/-ages/onestopexpress.html for information on the Express program and the associated fees. Contact the appropriate regional office Express Permit Coordinator for additional information and to schedule the required application meeting.) 5. A detailed narrative (one to two pages) describing the stormwater treatment/management 6. A USGS map identifying the site location. If the receiving stream is reported as class SA or the receiving stream drains to class SA waters within Y2 mile of the site boundary, include the Y2 mile radius on the map. 7. Sealed, signed and dated calculations (one copy). 8. Two sets of plans folded to 8.5" x 14" (sealed, signed, & dated), including: a. Development/Project name. b. Engineer and firm. c. Location map with named streets and NCSR numbers. d. Legend. e. North arrow. f. Scale. g. Revision number and dates. h. Identify all surface waters on the plans by delineating the normal pool elevation of impounded structures, the banks of streams and rivers, the MHW or NHW line of tidal waters, and any coastal wetlands landward of the MHW or NHW lines. • Delineate the vegetated buffer landward from the normal pool elevation of impounded structures, the banks of streams or rivers, and the MHW (or NHW) of tidal waters. i. Dimensioned proper ;T/project boundary with bearings & distances. j. Site Layout with all BUA identified and dimensioned. k. Existing contours, proposed contours, spot elevations, finished floor elevations. 1. Details of roads, drainage features, collection systems, and stormwater control measures. m. Wetlands delineated, or a note on the plans that none exist. (Must be delineated by a qualified person. Provide documentation of qualifications and identify the person who made the determination on the plans. n. Existing drainage (including off -site), drainage easements, pipe sizes, runoff calculations. o. Drainage areas delineated (included in the main set of plans, not as a separate document). Fonn SWU-101 Version Oct. 31, 2013 Page 4 of 6 for IQ p. Vegetated buffers (where required). 9. Copy of any applicable soils report with the associated SHWT elevations (Please identify --P A elevations in addition to depths) as well as a map of the boring locations with the existing elevations and boring logs. Include an 8.5"x11" copy of the NRCS County Soils map with the project area clearly delineated. For projects with infiltration BMPs, the report should also include the soil type, expected infiltration rate, and the method of determining the infiltration rate. (Infiltration Devices submitted to WiRO: Schedule a site visit for DEMLR to verify the SHWT prior to submittal, (910) 796-7378.) 10. A copy of the most current property deed. Deed book: see attached Page No: 11. For corporations and limited liability corporations (LLC): Provide documentation from the NC AIM Secretary of State or other official documentation, which supports the titles and positions held by the persons listed in Contact Information, item 1a, 2a, and/or 3a per 15A NCAC 2H.1003(e). The corporation or LLC must be listed as an active corporation in good standing with the NC Secretary of State, otherwise the application will be returned. http: / /www.secretgU.state.nc.us/Corl2oratims/CSearch.g§Rx VII. DEED RESTRICTIONS AND PROTECTIVE COVENANTS For all subdivisions, outparcels, and future development, the appropriate property restrictions and protective covenants are required to be recorded prior to the sale of any lot. If lot sizes vary significantly or the proposed BUA allocations vary, a table listing each lot number, lot size, and the allowable built -upon area must be provided as an attachment to the completed and notarized deed restriction form. The appropriate deed restrictions and protective covenants forms can be downloaded from http://l2ortal.ncdenr.org/web/lr/state-stormwater- forms does. Download the latest versions for each submittal. In the instances where the applicant is different than the property owner, it is the responsibility of the property owner to sign the deed restrictions and protective covenants form while the applicant is responsible for ensuring that the deed restrictions are recorded. By the notarized signature(s) below, the permit holder(s) certify that the recorded property restrictions and protective covenants for this project, if required, shall include all the items required in the permit and listed on the forms available on the website, that the covenants will be binding on all parties and persons claiming under them, that they will run with the land, that the required covenants cannot be changed or deleted without concurrence from the NC DEMLR, and that they will be recorded prior to the sale of any lot. VIII. CONSULTANT INFORMATION AND AUTHORIZATION Applicant: Complete this section if you wish to designate authority to another individual and/or firm (such as a consulting engineer and/or firm) so that they may provide information on your behalf for this project (such as addressing requests for additional information). Consulting Engineer: Ramon Marconi, PE Consulting Firm: Talbert & Bright, Inc. Mailing Address: 4810 Shelley Drive City: Wilmington Phone: (910 ) 763-5350 Email:rmarconi@tbiilm.com State: NC Zip: 28405 Fax: (910 ) 762-6281 IX. PROPERTY OWNER AUTHORIZATION (if Contact Information, item 2 has been filled out, complete this section) I, (print or type name of person listed in Contact Information, item 2a) , certify that I own the property identified in this permit application, and thus give permission to (print or type name of person listed in Contact Information, item 1a) with (print or type name of organization listed in Contact Information, item 1a) to develop the project as currently proposed. A copy of the lease agreement or pending property sales contract has been provided with the submittal, which indicates the party responsible for the operation and maintenance of the stormwater system. Form SWU-101 Version Oct. 31, 2013 Page 5 of 6 As the legal property owner I acknowledge, understand, and agree by my signature below, that if my designated agent (entity listed in Contact Information, item 1) dissolves their company and/or cancels or defaults on their lease agreement, or pending sale, responsibility for compliance with the DEMLR Stormwater permit reverts back to me, the property owner. As the property owner, it is my responsibility to notify DEMLR immediately and submit a completed Name/Ownership Change Form within 30 days; otherwise I will be operating astormwater treatment facility without a valid permit. I understand that the operation of a stormwater treatment facility without a valid permit is a violation of NC General Statue 143-215.1 and may result in appropriate enforcement action including the assessment of civil penalties of up to $25,000 per day, pursuant to NCGS 143-215.6. Date: a Notary Public for the State of do hereby certify that County of personally appeared before me this _ day of and acknowledge the due execution of the application for a stormwater permit. Witness my hand and official seal, SEAL My commission expires. X. APPLICANT'S CERTIFICATION I, (print or type name of person listed in Contact Information, item 1a) Granseur Dick, PE, CM certify that the information included on this permit application form is, to the best of my knowledge, correct and that the project will be constructed in conformance with the approved plans, that the required deed restrictions and protective covenants will be recorded, and that the proposed project complies with the requirements of the applicable stormwater rules under 15A NC C 2H .1000 and any other applicable state stormwater requirements. Signature: > cf// 4!F (f /4 Date: 7/9(2-&W I, IS a X M . Q aSK S a Notary Public for the State of N0)'"k C CD1 IN, , County of �,u� tAAw>J � do hereby certify that 06dn C : r- )Jt 6k- personally appeared before me this -6 day of AVC I v'�0 and ackpowledge the due execution of the application for a stormwater permit. Witness my hand and official seal, f V f , Air)sp- M NOTARY PUBLIC z ti9 ��, i tozR C�� NININ SEAL My commission expires I %� 1;-),V Form SWU-101 Version Oct. 31, 2013 Page 6 of 6 Project Name: Project Location: Maintenance Air Carrier Apron Expansion Phase 1 Wilmington International Airport rviaur►enance recorus snail De Kept on the following BMP(s). This maintenance record shall be kept in a log in a known set location. Any deficient BMP elements noted in the inspection will be corrected, repaired, or replaced Immediately. These deficiencies can affect the integrity of structures, safety of the public, and the pollutant removal efficiency of the BMP(s). The BMP(s) on this project include (check all that apply & corres Bioretention Cell Quantity: Dry Detention Basin Quantity: Grassed Swale Quantity: Green Roof Quantity: Infiltration Basin Quantity: Infiltration Trench Quantity: Level SpreaderNFS Quantity: Permeable Pavement Quantity: Proprietary System Quantity: Rainwater Harvesting Quantity: Sand Filter Quantity: Stormwater Wetland Quantity: Wet Detention Basin Quantity: Disconnected Impervious Area Present: User Defined BMP Present: onding O&M tables wil Location(s): Location(s): Location(s): Location(s): Location(s): Location(s): Location(s): Location(s): Location(s): Location(s): Location(s): Location(s): Location(s): Location(s): Location(s): 1 0 No No 16171, I acknowledge and agree by my signature below that I am responsible for the performance of the maintenance procedures listed for each BMP above, and attached O&M tables. I agree to notify NCDENR of any problems with the system or prior to any changes to the system or responsible party. * Responsible Party: Title & Organization: Street address: City, state, zip: Phone number(s): Email: Granseur Dick, PE. CM Facilities Director, New Hanover County Airport Authority 1740 Airport Boulevard, Suite 12 Wilmington, NC 28405 (910) 341-4333 dickLN ilm.com Signature: 1� L- ( l 2/ �dZ p Date: I, KD I V ` . '�l S -,a Notary Public for the State of }',JV '�{,� (04- 1 t kg. — County of KVu, .k-A`,,Oje r , do hearby certify thhatt 1i1VdVJSrWr D ck I� ,CM personally appeared before me this �� day of C IGl VV-k/L2c:k and acknowledge the due execution of the Oper ns and Main nance Agreem t . Witness m���irwd official seal, _ i a NorARY BAN 2 9�Z(1 PUBLIC y9y �. BY d My commission expires rrrrrom+� STORM-EZ Version 7.4 12/11/2019 O&M Manual Page 1 of 2 -- __ raSS wa a ntenanee egu rementS Important maintenance procedures: - The drainage area of the grassed Swale will be carefully managed to reduce the sediment load to the grassed Swale. - After the first-time fertilization to establish the grass in the Swale, fertilizer will not be applied to the grassed Swale. The grassed swale will be inspected once a quarter. Records of operation and maintenance will be kept in a known set location and will be available upon request. Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately. BMP element: Potential problem: How to remedlate the problem: The perimeter of the BMP Areas of bare soil and/or erosive gullies have formed. Regrade the soil if necessary to remove the gully, and then plant a ground cover and water until it is established. Provide lime and a one- time fertilizer application. Vegetation is too short or too long. Maintain vegetation at a height of approximately six inches. The entire length of the Swale Trash/debris is present. Remove the trash/debris. Areas of bare soil and/or erosive gullies have formed. Regrade the soil if necessary to remove the gully, and then re -sod (or plant with other appropriate species) and water until established. Provide lime and a one-time fertilizer application. Sediment covers the grass at the bottom of the swale. Remove sediment and dispose in an area that will not impact streams or BMPs. Re -sod if necessary. Vegetation is too short or too long. Maintain vegetation at a height of approximately six inches. The outlet device Clogging has occurred. Clean out the outlet device. Dispose of the sediment off -site. The outlet device is damaged Repair or replace the outlet device. The receiving water Erosion or other signs of damage have occurred at the Contact the local NC Department of Environment and Natural Resources Regional Office. outlet. c1v JAN 2 9 20Z0 BY_ STORM-EZ 12/11/2019 Version 1.4 O&M Manual Page 2 of 2 SUPPLEMENT-EZ COVER PAGE FORMS LOADED PROJECT INFORMATION --1-]Project Name ----- -- - --2 [Project Area (ac)— _ — _ _ _ . _ __._ -•-.---__-' 3 [Coastal Wetland Area (ac) Surface Water Area (ac) — Is this Project High or Low Density? Does this project use an off -site SCM? COMPLIANCE WITH 02H .1003(4)Y — _ 7 ! Width of vegetated setbacks provided (feet)- 9�S Will the vegetated setback remain vegetated? _ A other that as listed in .1003(D c d) ciut of the setback? 10 I Is streambank stabilization proposed on this project? i ILM Air Carrier Apron Expansion Phase I 0 for Swale (Overall Max DA). / 11.95 for Pro No Yes Yes No - NUMBER AND TYPE OF SCMs: a r € 11 1 Infiltration System ! 12 _ IBioretention Cell 1 13 Wet_ Pond 14 Stormwater Wetland !� 15 Permeable Pavement _ 16 Sand Filter 17 — JRainwater Harvesting ( EHJ_- 18 (Green Roof 19 —�- JLevel Spreader -Filter Stri LS-FS 20 JDisconnected Impervious Surface DIS — 21 [Treatment Swale 22 23 Dry Pond StorvnFllter —_--- - ---•---- .._:� 25 Bayfiker 26 IFilterra — — j I FORMS LOADED DESIGNER CERTIFICATION 27�Name and Title: 28 Organization: - -- — — — 29 Street address: 30 City, State, Zip: — -- _ 32 !Email: Ramon Marconi, PE / Project Engineer T F _Talbert & Bripht, Inc._ ` - - 4810 Shelly Drive Wilmington, NC 28405 _ _...... ....... t910) 763-5350_..._._.........,.:..:...-. Certification Statement I cerfify, under penalty of law that this Supplement-EZ form and all supporting information were prepared under my direction or supervision; that the information provided in the form is, to the best of my knowledge and belief, truc, accurate, and complete; and that the engineering plans, specifications, operation and maintenance agreements and other supporting information are consistent with the information provided here. z a� EP 2 Ogg5 �s� 9 s•.�FIVGIN�•. �V ``� �4;, E /f�111 Seal Signature of Designer Date L;L. a, DRAINAGE AREAS 1 � Is this a high density project? 2 _ If so, number of drainage areas/SCMs Is all/part of this protect subject to previous rule 3_ Iversions? FORMS LOADED AREA INFORMATION 4 ;Type of SCM 5 Total BUA in protect (sq ft) 1New BUA on subdivided lots (subject to permitting) 6 (sq ft) Yes No ! ? " Overall _ ACLX 04 Entire Site PreTreatment Swale 522720 sf propo eve fir-oi a J 're. he. bw R 1 PreTreatment Swale 224192 sf 'New BUA outside of subdivided lots (subject to� 7 jperrritting) (sf) 8 I Offsite - total area(sqft)_ Offsite BUA (sq 10 iBreakdown of new BUA outside subdivided lots: - Parking (sq ft) 121353 sf 121353 sf - Sidewalk (sq ft) — ; -Roof (sq ft) ^ _ Roadway (sg ft) _ - �- N 4252 sf 4252 sf -Future (sq ft) 298528 sf - Other, please specify in the comment box below (sq ft�_ 113433 sf 113433 sf New infiltrating permeable pavement on subdivided _11 Ilots _(sq ft).._ New infiltrating permeable pavement outside of 12 subdivided lots (sq ft) ^I Exisitng BUA that will remain (not subject to _ 13 ,permitting) (sq ft) 14 Existing BUA that is already permitted (sq ft)_--- 15 Existing BUA that will be removed (sq ft) 14846 sf 14846 sf 16 I Percent BUA 75% 43% 17 Design storm (inches) .75 in_/hr 75 in/hr 18 aDesign volume of SCM (cu ft) 901 cf� 548 cf 19 iCalculation method for design volume Rational Method Rational Method ADDITIONAL_ INFORMATION ,Please use this space to provide any additional information about the ! 20 drainage area_(s): Existing BUA to be treated and permitted, currently not permitted. _. p�1 J4N29 42 ::gay TREATMENT SWALE _1 iDrainag_e area number 3 - 2 jDesign volume of SC_M (cu ft) GENERAL MDC FROM 02H .1050 i Is the SCM sized to treat the SW from all surfaces 3 lat build -out? Yes 4 _ Is the SCM located away from contaminated soils? 5 What are the side slopes of the SCM (H:V)? 'M ^ 5 1 Dces the SCN! "Eve retaining walls, gabion_walls or 6 other engineered side slopes? No !Are the inlets, outlets, and receiving stream 7 I protected from erosion (10-year storm)? I Yes 8 Is there an overflow or bypass for inflow volume In excess of the design volume? No __ _" What is the method for dewatering the SCM for 9 maintenance? ! Pump (preferred) applicable, will the SCM be cleaned out after 10 Ilf construction? I Yes iM_D__C,(,8")_?_ - -- - _ _ _ Does the maintenance access comply with General11 Yes _ Does the drainage easement mply cowith General� IMDC 12 (9)? Yes If the SCM is on a single family lot, does (will?) the 13 -plat comply with General MDC (10)? _ r Is there an O&M Agreement that complies with-i 14 -15_ General MDC (11)? Yes_ _ Is there an O&M Plan that complies with General j MDC (12)? Yes - 16 Does the SCM follow the device specific MDC? — Yes - - Was e��AA-designed by an licensed 17 professional? j Yes TREATMENT SWALE MDC FROM 02H .1061 18 ISHW_T elevation (fmsl) _ 7 ' -' 19 Bottom of the treatment swale (fmsl) 15.20 treatment swale (feet) _; 6 fit Is swale trapezoidal in shape?- 20 I.Depthof 21 - 22 Width of bottom of swale (feet)—`6 fit 23 Side slopes of treatment swale (H:U)_ — I- * 5:1 24 Length of swale (feet) _ 25 Flow depth during the 0.75 inch/hour storm (inches) 5.64 in Velocity during the 0.75 inch/hour storm (feet per ":----'-•-__..-.._.--._ 26 'second) 27 ` 2.27 cfs Hydraulic retention time for swale ((minutes) 4 95 min 28 Species of grass that will be used �- Bermuda Grass i I6 Will the grass be maintained at an average height of.'- 29 inches? TO-1Will the_ grass not 6e cut lower than _4 inches? i Velocity during the 10-year storm (feet per second) 4.29 fUs —Y _. jWdfineasures_betaken to preverit erosion cE rmg 32 'the 10-year storm? I Yes _ ADDITIONAL INFORMATION-� I Please use this space to provide any additional 33 information about the treatment swale(s): J 8Y•.� AN 2 9 2020 DE1YfLR USE ONLY Date Aeceived Fee Paid Permit Number ao a© :It 7 `-= I SW & O Applicable Rul s: I ❑ Coastal SW -1995 ❑ Coastal SW - 2008 ❑ Ph Il - Post Construction (select all that apply) ❑ Non -Coastal SW- HQW/ORW Waters ❑ Universal Stormwater Management Plan ❑ Other WQ Mgmt Plan: State of North Carolina [-'ECr—JVDelpartment of Environment and Natural Resources E0 Division of Energy, Mineral and Land Resources / � ,��? Z i fv�f STORMWATER MANAGEMENT PERMIT APPLICATION F - .._.. . This form may be photocopied for use as an original I. GENERAL INFORMATION 1. Project Name (subdivision, facility, or establishment name - should be consistent with project name on plans, specifications, letters, operation and maintenance agreements, etc.): Air Carrier Apron Expansion Phase I at Wilminp-ton International Airport 2. Location of Project (street address): 1740 Airport Boulevard City -.Wilmington County:New Hanover Zip:28405 3. Directions to project (from nearest major intersection): From the Martin Luther King Blvd/US 74 exit to N. 23rd St turn left onto N 23Rd St Travel appox 0.47 miles. Turn right onto Airport Boulevard (Main airport entrance) Project accces is appox 0.21 miles on the right down the first gravel road (south of Gardner Road). Travel approx. 0.40 miles to project/gate entrance 4. Latitude:34° 15' 53" N Longitude:77° 54' 47" W of the main entrance to the project. II. PERMIT INFORMATION: 1. a. Specify whether project is (check one): ❑New ®Modification ❑ Renewal w/ Modificationt tRenewals with modifications also requires SK i 102 - Renewal Application Form b.If this application is being submitted as the result of a modification to an existing permit, list the existing permit number SW8 050547 , its issue date (if known) October 3, 2019 , and the status of construction: ❑Not Started ❑Partially Completed* ® Completed* *provide a designer's certification 2. Specify the type of project (check one): ❑Low Density ®High Density ❑Drains to an Offsite Stormwater System ❑Other 3. If this application is being submitted as the result of a previously returned application or a letter from DEMLR requesting a state stormwater management permit application, list the stormwater project number, if assigned, n/a and the previous name of the project, if different than currently proposed, n/a 4. a. Additional Project Requirements (check applicable blanks; information on required state permits can be obtained by contacting the Customer Service Center at 1-877-623-6748): ❑LAMA Major ®Sedimentation/Erosion Control: 11.0 ac of Disturbed Area ❑NPDES Industrial Stormwater ❑404/401 Permit: Proposed Impacts b.If any of these permits have already been acquired please provide the Project Name, Project/Permit Number, issue date and the type of each permit:Air Carrier Apron Expansion Phase I, NEWHA-2020-013 5. Is the project located within 5 miles of a public airport? ❑No ®Yes If yes, see S.L. 2012-200, Part VI. http://portal.ncdenr.org/web/Ir/rules-and-regulations Form SWU-101 Version Oct. 31, 2013 Page 1 of 6 III. CONTACT INFORMATION 1. a. Print Applicant / Signing Official's name and title (specifically the developer, property owner, lessee, designated government official, individual, etc. who owns the project): Applicant/Organization: New Hanover County Airport Authority Signing Official & Title: Granseur Dick, PE, Facilities Director b. Contact information for person listed in item 1a above: Street Address:1740 Airport Bouleverd, Suite 12 City: Wilmington State: NC Zip: 28405 Mailing Address (if applicable): 1740 Airport Bouleverd, Suite 12 City: Wilmington Phone: (910 ) 341-4333 Email: gdick®flyilm.com State: NC Zip: 28405 Fax: (910 ) 341-3465 c. Please check the appropriate box. The applicant listed above is: ® The property owner (Skip to Contact Information, item 3a) ❑ Lessee* (Attach a copy of the lease agreement and complete Contact Information, item 2a and 2b below) ❑ Purchaser* (Attach a copy of the pending sales agreement and complete Contact Information, item 2a and 2b below) ❑ Developer* (Complete Contact Information, item 2a and 2b below.) 2. a. Print Property Owner's name and title below, if you are the lessee, purchaser or developer. (This is the person who owns the property that the project is located on): Property Owner/Organization: Signing Official & Title:_ b. Contact information for person listed in item 2a above: Street Address: City: State: Zip: Mailing Address (if applicable): City: State: Zip: Phone: ( ) Fax: ( ) Email: 3. a. (Optional) Print the name and title of another contact such as the project's construction supervisor or other person who can answer questions about the project: Other Contact Person/Organization: Ramon Marconi. PE / Talbert & Bright Inc Signing Official & Title: Ramon Marconi, PE, Project Engineer b. Contact information for person listed in item 3a above: Mailing Address: 4810 Shelley Drive City: Wilmington State: NC Zip: 28405 Phone: (910 ) 763-5350 Fax: (910 ) 762-6281 Email:rmarconi®tbiilm.com 4. Local jurisdiction for building permits: New Hanover County Point of Contact:)ay Graham Phone #: 910 798-717 APR 2 1 MQ Form SWU-101 'Version Oct. 31, 2013 Page 2 of 6 BYE PROJECT INFORMATION 1. In the space provided below, briefly summarize how the stormwater runoff will be treated. Theyroiect will be revising the drainage area to the exisiting permitted Extended Dry Detention Basin No.1, and adding an additional pretreatment swale (PreTreatment Swale #3). Project will utilize 224192 square feet of the previsouly_permited allocated built -upon area under permit SW8 050547 2. a. If claiming vested rights, identify the supporting documents provided and the date they were approved: Approval of a Site Specific Development Plan or PUD Approval Date: Valid Building Permit Issued Date: Other: Date: b. If claiming vested rights, identify the regulation(s) the project has been designed in accordance with: ® Coastal SW -1995 ❑ Ph II - Post Construction 3. Stormwater runoff from this project drains to the Cape Fear River basin. 4. Total Property Area:1620.8 acres 5. Total Coastal Wetlands Area: n/a acres 6. Total Surface Water Area: n/a acres 7. Total Property Area (4) - Total Coastal Wetlands Area (5) - Total Surface Water Area (6) = Total Project Area+:322.34 acres + Total project area shall be calculated to exclude the following: the normal pool of impounded structures, the area between the banks of streams and rivers, the area below the Normal High Water (N� line or Mean High Water (MHVV) line, and coastal wetlands landward from the NHW (or MHV� line. The resultant project area is used to calculate overall percent built upon area (BLIA). Non -coastal wetlands landward of the NHW (orMHV11) line may be included in the total project area. 8. Project percent of impervious area: (Total Impervious Area / Total Project Area) X 100 = 69.4 % 9. How many drainage areas does the project have? 1 (For high density, count I for each proposed engineered stormwater BMP. For low density and other projects, use I for the whole property area) 10. Complete the following information for each drainage area identified in Project Information item 9. If there are more than four drainage areas in the project, attach an additional sheet with the information for each area provided in the same format as below. Pretreatment Overall Phase I & II c.... I— n Futiira Phnco III Basin Information Drainage Area 1 Drainage Area _ Drainage Area Drainage Area Receiving Stream Name Smith Creek Smith Creek _ Smith Creek _ Smith Creek Stream Class * C, Sw C, Sw C, Sw C, Sw Stream Index Number * 18-74-63 18-74-63 18-74-63 18-74-63 Total Drainage Area (sf) 14,041,075 12,529,107 696,960 1,511,968 On -site Drainage Area (sf) 14,041,075 12,529,107 696,960 1,511,968 Off -site Drainage Area (sf) 0 0 0 0 Proposed Im ervious Area's (so 1 9,751,185 8,520,835 522,720 1,230,350 % Impervious Area** total 69.4 % 68.0 % 75.0 % 81.4 % Overall Phase I & II Pre Swale 3 Future Phase III Impervious' Surface Area Drainage Areal Drains a .Area _ Drama a Area _ Drainage Area On -site Buildings/Lots (sf) 0 0 0 _ 0 On -site Streets (sf) 4,252 4,252 4,252 0 On -site Parking (sf) 121,353 121,353 121,353 0 On -site Sidewalks (so 0 0 0 0 Other on -site (sf) 0 0 0 0 Future (sf) 3,454,162 2,223,812 298,528 1,230,350 Off -site (sf) 0 1 0 1 0 0 Existing BUA*** (sf) 6,171,418 6,171,418 98,587 0 Total (sf): 9,751,185 8,520,835 522,720 1,230,350 T Stream Class and index Number can be determined at: http. portal.ncdenr.or /wg eb/wq&s/csu/classifications Impervious area is defined as the built upon area including, but not limited to, buildings, roads, parking areas, sidewalks, gravel areas, etc. Form SWU-101 Version Oct. 31, 2013 Page 3 of 6 'Report only that amount of existing BUA that will remain after development. Do not report any existing BUA that is to be removed and which will be replaced by new BUA. 11. How was the off -site impervious area listed above determined? Provide documentation. Tributary area is entirely on -site. Proiects in Union County: Contact DEMLR Central Ojjice staff to check if the project is located within a Threatened & Endangered Species watershed that may be subject to more stringent stormwater requirements as per 1 SA NCAC 02B .0600. V. SUPPLEMENT AND O&M FORMS The applicable state stormwater management permit supplement and operation and maintenance (O&M) forms must be submitted for each BMP specified for this project. The latest versions of the forms can be downloaded from htt2://portal.ncdenr.org/web/wq/ws/su/bmp-manual. VI. SUBMITTAL REQUIREMENTS Only complete application packages will be accepted and reviewed by the Division of Energy, Mineral and Land Resources (DEMLR). A complete package includes all of the items listed below. A detailed application instruction sheet and BMP checklists are available from h!tg://portal.ncdenr.org/web/wq/ws/­su/statesw/forms dots. The complete application package should be submitted to the appropriate DEMLR Office. (The appropriate office may be found by locating project on the interactive online map athlip://portal.ncdeirir.org/web/wq/ws/su/maps.) Please indicate that the following required information have been provided by initialing in the space provided for each item. All original documents MUST be signed and initialed in blue ink. Download the latest versions for each submitted application package from http://portal.ncdenr.org/web/wq/ws/su/statesw/forms does. .tials 1. Original and one copy of the Stormwater Management Permit Application Form. 642, 2. Original and one copy of the signed and notarized Deed Restrictions & Protective Covenants LA Form. (if required as per Part VII below) 3. Original of the applicable Supplement Form(s) (sealed, signed and dated) and O&M agreement(s) for each BMP. 4. Permit application processing fee of $505 payable to NCDENR. (For an Express review, refer to http://www.envhel�org/pages/onestopexRress.hbnl for information on the Express program and the associated fees. Contact the appropriate regional office Express Permit Coordinator for additional i-nformatioit and to schedule the required application meeting.) 5. A detailed narrative (one to two pages) describing the stormwater treatment/management 6. A USGS map identifying the site location. If the receiving stream is reported as class SA or the receiving stream drains to class SA waters within 1/2 mile of the site boundary, include the 1/2 mile radius on the map. 7. Sealed, signed and dated calculations (one copy). 8. Two sets of plans folded to 8.5" x 14" (sealed, signed, & dated), including: a. Development/Project name. b. Engineer and firm. c. Location map with named streets and NCSR numbers. d. Legend. e. North arrow. f. Scale. g. Revision number and dates. h. Identify all surface waters on the plans by delineating the normal pool elevation of impounded structures, the banks of streams and rivers, the MHW or NHW line of tidal waters, and any coastal wetlands landward of the MHW or NHW lines. • Delineate the vegetated buffer landward from the normal pool elevation of impounded structures, the bar Ks of streams or rivers, and the MHW (or NHW) of tidal waters. i. Dimensioned property/project boundary with bearings & distances. j. Site Layout with all BUA identified and dimensioned. for k. Existing contours, proposed contours, spot elevations, finished floor elevations.lee 1. Details of roads, drainage features, collection systems, and stormwater control measures. 42- Or ., ..-A m. Wetlands delineated, or a note on the plans that none exist. (Must be delineated by a qualified person. Provide documentation of qualifications and identify the person who APR 2 2020 i made the determination on the plans. n. Existing drainage (including off -site), drainage easements, pipe sizes, runoff calculations. BY i o. Drainage areas delineated (included in the main set of plans, not as a separate document). Form aVVU-101 Version Oct. 31, 2013 Page 4 of 6 p. Vegetated buffers (where required). G� 9. Copy of any applicable soils report with the associated SHWT elevations (Please identify G elevations in addition to depths) as well as a map of the boring locations with the existing elevations and boring logs. Include an 8.5"x11" copy of the NRCS County Soils map with the project area clearly delineated. For projects with infiltration BMPs, the report should also include the soil type, expected infiltration rate, and the method of determining the infiltration rate. (Infiltration Devices submitted to WiRO: Schedule a site visit for DEMLR to verify the SHWT prior to submittal, (910) 796-7378.) 10. A copy of the most current property deed. Deed book: see attached Page No: 11. For corporations and limited liability corporations (LLC): Provide documentation from the NC Secretary of State or other official documentation, which supports the titles and positions held by the persons listed in Contact Information, item 1a, 2a, and/or 3a per 15A NCAC 2H.1003(e). The corporation or LLC must be listed as an active corporation in good standing with the NC Secretary of State, otherwise the application will be returned. hffp://www.secretaiy.state.nc.us/Corporations/CSearch.aspx VII. DEED RESTRICTIONS AND PROTECTIVE COVENANTS For all subdivisions, outparcels, and future development, the appropriate property restrictions and protective covenants are required to be recorded prior to the sale of any lot. If lot sizes vary significantly or the proposed BUA allocations vary, a table listing each lot number, lot size, and the allowable built -upon area must be provided as an attachment to the completed and notarized deed restriction form. The appropriate deed restrictions and protective covenants forms can be downloaded from http://12ortal.ncdenr.org/web/lr/state-stormwater- forms does. Download the latest versions for each submittal. In the instances where the applicant is different than the property owner, it is the responsibility of the property owner to sign the deed restrictions and protective covenants form while the applicant is responsible for ensuring that the deed restrictions are recorded. By the notarized signature(s) below, the permit holder(s) certify that the recorded property restrictions and protective covenants for this project, if required, shall include all the items required in the permit and listed on the forms available on the website, that the covenants will be binding on all parties and persons claiming under them, that they will run with the land, that the required covenants cannot be changed or deleted without concurrence from the NC DEMLR, and that they will be recorded prior to the sale of any lot. VIII. CONSULTANT INFORMATION AND AUTHORIZATION Applicant: Complete this section if you wish to designate authority to another individual and/or firm (such as a consulting engineer and/or firm) so that they may provide information on your behalf for this project (such as addressing requests for additional information). Consulting Engineer: Ramon Marconi, PE Consulting Firm:_ Talbert & Bright, Inc. Mailing Address: 4810 Shelley Drive City: Wilmington State: NC Zip: 28405 Phone: (910 ) 763-5350 Fax: (910 ) 762-6281 Email:rmarconi@tbiilm.com IX. PROPERTY OWNER AUTHORIZATION (if Contact Information, item 2 has been filled out, complete this section) I, (print or type name of person listed in Contact Information, item 2a) . certify that I own the property identified in this permit application, and thus give permission to (print or type name of person listed in Contact Information, item 1a) with (print or type name of organization listed in Contact Information, item 1a) to develop the project as currently proposed. A copy of the lease agreement or pending property sales contract has been provided with the submittal, which indicates the party responsible for the operation and maintenance of the stormwater system. Form SWU-101 Version Oct. 31, 2013 Page 5 of 6 As the legal property owner I acknowledge, understand, and agree by my signature below, that if my designated agent (entity listed in Contact Information, item 1) dissolves their company and/or cancels or defaults on their lease agreement, or pending sale, responsibility for compliance with the DEMLR Stormwater permit reverts back to me, the property owner. As the property owner, it is my responsibility to notify DEMLR immediately and submit a completed Name/Ownership Change Form within 30 days; otherwise I will be operating a stormwater treatment facility without a valid permit. I understand that the operation of a stormwater treatment facility without a valid permit is a violation of NC General Statue 143-215.1 and may result in appropriate enforcement action including the assessment of civil penalties of up to $25,000 per day, pursuant to NCGS 143-215.6. I, a Notary Public for the State of do hereby certify that before me this _ day of Date: County of personally appeared , and acknowledge the due execution of the application for a stormwater permit. Witness my hand and official seal, SEAL My commission expires X. APPLICANT'S CERTIFICATION I, (print or type name of person listed in Contact Information, item 1a) Granseur Dick, PE, CM certify that the information included on this permit application form is, to the best of my knowledge, correct and that the project will be constructed in conformance with the approved plans, that the required deed restrictions and protective covenants will be recorded, and that the proposed project complies with the requirements of the applicable stormwater rules under 15A NC C 2H .1000 and any other applicable state stormwater requirements. Signature: R,! CM Date: ��zo Z C% d > � � I, RD � r 1 ' • 1✓ a,6 S a Notary Public for the State of Newik 1, ral w, , County of do hereby certify that 'YaVlS' ur NG�. personally appeared before me this 1 day of C SMY3 and acknowledge the due execution of the application for a stormwater permit. Witness my hand and official seal, t NOTARY PUBLIC OVER GG19 Form SWU-101 Version Oct. 31, 2013 SEAL My commission expires , chi' ea A"M rtl.�'. -. APR' 10 8Y,• r Page 6 of 6 Project Name: Project Location: reement Air Carrier Apron Expansion Phase 1 Wilmington International Airport Maintenance records shall be kept on the following BMP(s). This maintenance record shall be kept in a log in a known set location. Any deficient BMP elements noted in the inspection will be corrected, repaired, or replaced immediately. These deficiencies can affect the integrity of structures, safety of the public, and the pollutant removal efficiency of the BMP(s). The BMP(s) on this project include (check all that apply & cc Bioretention Cell Quantity: Dry Detention Basin Quantity: Grassed Swale Quantity: Green Roof Quantity: Infiltration Basin Quantity: Infiltration Trench Quantity: Level SpreaderNFS Quantity: Permeable Pavement Quantity: Proprietary System Quantity: Rainwater Harvesting Quantity: Sand Filter Quantity: Stormwater Wetland Quantity: Wet Detention Basin Quantity: Disconnected Impervious Area Present: User Defined BMP Present: ng O&M tables wil Location(s): Location(s): Location(s): Location(s): Location(s): Location(s): Location(s): Location(s): Location(s): Location(s): Location(s): Location(s): Location(s): Location(s): Location(s): oe aaaea a I acknowledge and agree by my signature below that I am responsible for the performance of the maintenance procedures listed for each BMP above, and attached O&M tables. I agree to notify NCDENR of any problems with the system or prior to any changes to the system or responsible party. * Responsible Party: Title & Organization: Street address: City, state, zip: Phone number(s): Email: Granseur Dick, PE, CM Facilities Director, New Hanover County Airport Authority 1740 Airport Boulevard, Suite 12 Wilmington, NC 28405 (910) 341-4333 gdick@flyilm.com Signature: cz� �Pz- Date: 02a I, a0, Vi S a Notary Public for the State of I r )el - County of do hearby certify that V(-!:A— L j,L E Ll� personally appeared before me this l day of X-Y�.tG. (- y— . �Q c� and acknowledge the due execution of the Operatiggs and Mainlonance Agreement . Witness my hand and official seal, 0. .� NIIIINIgI was oq� NOTARY PUBLIC 3 rt� ti �� I Seal Pve CD MY commission expires STORM-EZ 12/11/2019 Version 1.4 O&M Manual Page 1 of 2 Grassed ware Maintenance Re au cements Important maintenance procedures: _ The drainage area of the grassed swale will be carefully managed.to reduce the sediment load to the grassed swale. After the first-time fertilization to establish the grass in the swale, fertilizer will not be applied to the grassed swale. The grassed swale will be inspected once a quarter. Records of operation and maintenance will be kept in a known set location and will be available upon request. Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately. BMP element: Potential problem: Flow to remediate the problem: The perimeter of the BMP Areas of bare soil and/or erosive gullies have formed. Regrade the soil if necessary to remove the gully, and then plant a ground cover and water until it is established. Provide lime and a one- time fertilizer application. Vegetation is too short or too long. Maintain vegetation at a height of approximately six inches. The entire length of the Trash/debris is present. Remove the trash/debris. swale Areas of bare soil and/or erosive gullies have formed. Regrade the soil if necessary to remove the gully, and then re -sod (or plant with other appropriate species) and water until established. Provide lime and a one-time fertilizer application. Sediment covers the grass at the bottom of the swale. Remove sediment and dispose in an area that will not impact streams or BMPs. Re -sod if necessary. Vegetation is too short or too long. Maintain vegetation at a height of approximately six inches. The outlet device Clogging has occurred. Clean out the outlet device. Dispose of the sediment off -site. The outlet device is damaged Repair or replace the outlet device. The receiving water Erosion or other signs of Contact the local NC Department of Environment and Natural damage have occurred at the Resources Regional Office. outlet. STORM-EZ 12/11 /2019 Version 1.4 O&M Manual Page 2 of 2 SUPPLEMENT-EZ COVER PAGE FORMS LOADED :PROJECT INFORMATION 1 1 Pro ect Name j—__ _ __— —!_ ILM Air Carrier Apron Ex 2 i Project Area ac Max D -- .— 3 Coastal Wetland Area (ac) i 0 4 Surface Water Area c (a —� 0 5 .Is this project High or Low Density? 6 i Does this 1ro ect use an off -site SCM? .-----i--- - P - 1 E90 COMPLIANCE WITH 02H .1003(4) _ 7 (Width of vegetated setbacks provided (feetZ 50 d; 8 Will the vegetated setback remain vegetated? --- T_Yes " 9 Is BUA other that as listed in .1003(4)(c d out of the setback? Yes ;, 10 -is streambank stabilization proposed on this project? I No / 11.95 for NUMBER AND TYPE OF SCMw 11 Infiltration System 12 ,BI ioretention Cell _.__----•- -:.-----_ 13 (Wet Pond i __._...._...._ .. ._.___-__._. 14 z 15 ' ;Stormwater Wetland (Permeable Pavement ISand Filter i i _._... _16 f 17 Rainwater Harvesting RWH 18 JGreen Roof a 19 20 21 (Treatment Ttvel S reader -Filter Strip (LS-FS) Disconnected Impervious Surface DIS Swale 22_ Dry Pond 23 StormFilter—__— —' -._..._� ---•_— �__ 24 Silva Ce01.--._- —_—_ _ !__-- - - 28 _ FORMS LOADED T10N 28 iO gr anization:— - —�� _ — — _j- Talbert & Bright. Inc. 29 Street address:— _ I -y ~-- 4810 Shelly Drive 30 JCity, State, Zip: 31 1Phone numbers):(910 763-5350- 32 I Email: I -- rmnrmniMhillm mm Certffication Statement I certify, under penalty of law that this Supplement-FZ form and all supporting information were prepared under my direction or supervision; that the information provided in the form ;3, to the best of my knowledge and belief, true, accurate, and complete: end that the engineering plans, specifications, operation and maintenance agreements and other supporting information are consistent with the information provided here. ``����• GA•RO4 R- FE SI • r. 034503 �i� y•FNGIN;;.•'�V���� �ito s��'ON E 1 fill iM, % 1 Signature of Designer'~ Date DRAINAGE AREAS 1 j Is this a high density project? _2 i If so, -number of drainage are, as/SCM_s_y i Is all/part of this project subject to previous rule 3 versions? FORMS LOADED Yes 1 No �ver�El 0A Pi,; e,Qa __ DRAINACaE AREA INFORMATION Entire Site 1 I PreTreatment PreTreatment 4 Type of SCM Swale Swale 5 Total_ BUA in project (sq.ft) _ 52272. 0 sf 224192 sf - _ _ I New BUA on subdivided lots (subject to permitting) New BUA outside of subdivided lots (subject to permitting) (sf) _7_ 8_ fOffsite -total area (sq ft), _ BUA (sq ft _ _-9_IOffsite 10 Breakdown of new BUA outside subdivided lots: 121353 sf 121353 sf Parking_(sq ft) _ _ _ Sidewalk (sq ft) - Roof (sq ft) - Roadway s� ft) 4252 sf 4252 sf _: r _� Future (sq ft) 298528 sf _ ._ _ - Other, please specify in the comment box _ below (sq ft) _ _ _ 113433 sf 113433 sf infiltrating permeable pavement on subdivided lots (sq ft)_` _11_�New New infiltrating permeable pavement outside of 12 (subdivided lots (sq ft)_ _ Exisitng BUA that will remain (not subject to 13___ permitting) (sq ft)_ 14 Existing BUA that is already permitted (sq ft) _ 15 ,Exist ng�BUA that will be removed (sq ft) 14846 sfl 14846fsfv 16 I Percent BUA 75% 43% 17 jDesign storm (inches) .75 in/hr _ .75 in/hr� 18 iDesign volume of SCM_(cu ft)� 901 cf W� 548 cf -� 1alculation method for design volume Rational Method Rational Method ADDITIONAL_ INFORMATION j Please use this space to provide any additional information about the 20 drainage area(s_): Existing BUA to be treated and--_.�-_e_.� - permitted; currently not permitted. permitted_ TREATMENT SW_ AL_E__ _ 1 Dra_hag_earea number f D _ 2 esign_volume of SCM (cu ft) 3 lIs the SCM sized to treat the SW from all surfaces j at build -out? I 4 lis the SCM located away from contaminated soils? l -_5• tl What are the side 'slopes of the SCM (H:V)? Does the SCM have retaining walls, gabion walls or _6 other engineered side slopes? _ Are the inlets, outlets, and receiving_ st_ream -! _7 protected from erosion (10-year storm)? - Ils there an overflow or bypass for inflow volume in ` 8 excess of the design volume? _ 9 1WIis the method for dewatering the SCM for ii-fmaintenance? Pump If applicable, will the SCM be cleaned out after , _ 10 construction? 11 !Does the maintenance access comply with General _ MDC (8)? _ Does the drainage easement comply with General -� _ 12 (MDC (9)? _ If the SCM is on a single family lot, -does (will?) the 13_ plat comply with General MDC (10)? 14 lIs there an O&M Agreement that complies with General MDC (11)? _ Is there an O&M Plan that complies with General _ 15 1MDC (12)? 16 Does the SCM follow the device specific MDC? - --TVV'E s the TCM7cresigned by an NC licensed "-"-- 17 1 professional? TREATMENT; SWALE, MDC FRC _18 JSHWT elevation (fmsl) 19 _20 21- _22 I Bottom of the treatment si Depth of treatmt le swa en 1Is swale trapezoidal in sh, Width of bottom of swale, 23 Side slopes of treatment 24 Length of swale (feet) ale (H:V) Yes Yes 5511 No Yes No (pre! Yes Yes Yes Yes Yes Yes Yes 15-20 25 1 Flow depth during the 0.75 inch/hour storm (inches) _ 5.64 in !Velocity during the 0.75 inch/hour storm (feet per 26 second) 2.27 cfs 27 Hydraulic retention time for Swale (minutes) _ i 4'95 min 28 `[Species of grass that will be used _ Bermuda Grass Will the grass be rnamainavera ted'at an ge height of`•: _ 29 6 inches? i Yes - 30 Will the grass not be cut lower than 4 inches? -.- i Yes . _ 31 ( Velocity during the 10-year storm (feet per second) _ _-4 29 ft/s 32 IWildmeasures be taken to prevenf erosion3uring -!' .the 10-year storm? Yes ADDITIONAL INFORMATION 33 I Please use this space to provide any additional information about the treatment swale(s): 5410 Trinity Road TIC► MONS GROUP Suite102 YOUR VISION ACHIEVED THROUGH OURS. Raleigh. NC 27607 TO: TRANSMITTAL, NCDEQ — Christine Hall Stormwater Department 127 Cardinal Drive Extension Wilmington, NC 28405 P 919.866.4951 F 919.859.5663 www.timnwns.com Date: 10/2120 Job#: 37630.054 Circle K — NTI Airport Blvd Wilmington — Project: NC.115 Reference: Copies Sent To: COPIES DATE NUMBER DESCRIPTION 2 10/2/2020 1 Stormwater Management Permit Application 2 10/2/2020 2 Deed Restrictions and Protective Covenants Form 1 10/2/2020 3 SCM Supplements Forms 1 10/2/2020 4 Permit Application Fee Check $505 Check #: 87813 1 10/2/2020 5 Detailed Narrative 1 10/2/2020 6 USGS Ma 1 10/2/2020 7 Calculations Package included SHWT report) 2 10/2/2020 8 Folded 24" x 36" plans 1 10/2/2020 9 Copy of Property Deed 1 10/2/2020 10 NC Secretary of State Registration — Circle K Meredith W Rice 1 10/2/2020 11 Property Agreement between County and Airport 1 10/212020 12 O&M Agreements 1 10/2/2020 13 ILM Stormwater Master Plan 1 10/2/2020 14 Wetlands Documentation 1 10/2/2020 15 CD containing dfs of all documents THESE ITEMS ARE TRANSMITTED: If enclosures are not as noted, please notify us at once. COMMENTS: Thank You, Brian Downs Project Manager Timmons Group CIVIL ENGINEERUNG i ENVIROWIENTAL I SURVEYIF;G I GIS I LANDSCAPE ARCHITECTURE j CONSTRUCTION SERVICES TALBERT & BRIGHT, INC. ENGINEERING & PLANNING CONSULTA LETTER OF TRANSMITTAL To: NC Division of Environmental Quality Land Resources 127 Cardinal Drive Ext, Wilmington, NC 28405 WE ARE SENDING YOU: ❑ Shop Drawings ❑ Copy of Letter ® Attached ❑ Prints ❑ Change Order �0 OCT 05 2020 ;[§_ V` Date: 10/05/20 Pro'. No. 3301-1702 Attention: Garrett Zorda Re: Wilmington International Airport Air Carrier Apron Expansion Phase 1 Stormwater Permit Modification — Permit No. SW8 050547 ❑ Under Separate Cover via ® Plans ❑ Other the following items: ❑ Specifications ITEM DATE NO. DESCRIPTION 1 Second copy of revised plans and documentation: 1 • TBI response letter dated July 20, 2020 to NCDEQ comment letter dated July 20, 2020 1 • updated table in form SWU-101, Section IV. 10 1 • stand-alone updated table from form SWU-101, Section IV. 10 sent electronically on July 17, 2020 1 • Revised full size plan sheet C1 1 • Revised full size plan sheet ESC3 THESE ARE TRANSMITTED, as checked below: ® For Approval ❑ No Exception taken ❑ For your Use ❑ Make Corrections Noted ❑ For Review and Comment ❑ Amend and Resubmit ❑ As Requested ❑ Rejected — See Remarks ❑ FOR BIDS DUE ON REMARKS ❑ Resubmit Copies for Approval ❑ Submit Copies for Distribution ❑ Return Corrected Prints ❑ Prints Returned After Loan to Us ❑ Other COPY TO Granseur Dick, PE (half size plan sheets) SIGNED Ray Marconi, PE ENGINEERING & PLANNING CONSULTANTS 4810 Shelley Drive Wilmington, NC 28405 910.763.5350 FAX 910.762.6281 Zorda, Garrett D From: Zorda, Garrett D Sent: Friday, October 2, 2020 11:27 AM To: Ray Marconi; Granseur Dick (gdick@flyilm.com) Subject: Wilmington International Airport EDDB (SW8 050547) - Request for Additional Information Good Morning All, I am finishing reviewing the additional information received on July 20, 2020 for the subject project. Everything looks mostly good to go, however, only one set of the revised plans were submitted. In order to ensure the permittee received an approved copy of the plans, it is necessary to submit two (2) copies of all revised plans and documentation. As such, can you please submit a second copy of the revised plans? With that said, I will begin drafting the permit so that once the revised plans are received, it should be mostly ready to go. Please ensure the requested information is received by October 19, 2020. In the meantime, if you have any questions or concerns, please let me know. Thanks, Garrett Zorda Environmental Engineer Division of Energy, Mineral and Land Resources State Stormwater Program Department of Environmental Quality 910 796 7215 office 910 796 7343 direct —Please note the change to my direct phone number"* garrettzordaancdenr.gov 127 Cardinal Drive Ext. Wilmington, NC 28405 N C�FCn.3rw 111A id th w�e�r mil C!.'. . _.. 7 ihiS i[. d!'eSS 7S SllbjfF -,t 10 tllr? ar)d fr � y be (l;. s it15 du .+laird parties. North Carolina Secretary of State Search Results Page 1 of 3 • File an Annual Report/Amend an Annual Report • Upload a PDF Filing • Order a Document Online • Add Entity to My Email Notification List • View Filings • Print a Pre -Populated Annual Report form Business Corporation Legal Name Circle K Stores Inc. Prev Legal Name Circle K Convenience Stores, Inc. Prev Legal Name The Circle K Corporation Information Sosld: 0176043 Status: Current -Active O Date Formed: 10/25/1985 Citizenship: Foreign State of Incorporation: TX Fiscal Month: April Annual Report Due Date: August 15th Registered Agent: Corporation Service Company Addresses Mailing 1130 West Warner Road, Building B Tempe, AZ 85284-2816 Reg Office 2626 Glenwood Avenue, Suite 550 Raleigh, NC 27608-1370 Officers Principal Office 1130 West Warner Road, Building B Tempe, AZ 85284-2816 Reg Mailing 2626 Glenwood Avenue, Suite 550 Raleigh, NC 27608-1370 https://www.sosnc.gov/online services/search/Business Registration Results 9/2/2020 North Carolina Secretary of State Search Results Page 2 of 3 Assistant Secretary Senior Vice President Vice President Kimberly Andrews Brian Bednarz Rodney Blanton 5500 S Quebec St. Suite 100 25 W. Cedar Street, Suite 100 2440 Whitehall Park Dr Greenwood Village CO 80111 Pensacola FL 35202 Charlotte NC 28273 Assistant Secretary Senior Vice President Aaron Brooks Kathy Cunnington 305 Gregson Dr. 1130 West Warner Road Building B Cary NC 27511 Tempe AZ 85284 Treasurer Kathy Cunnington 1130 West Warner Road Building B Tempe AZ 85284 Assistant Secretary Mike Foster 2440 Whitehall Park Drive, Suite 800 Charlotte NO 28273 Assistant Secretary Kim Kwiatkowski 1130 West Warner Road, Building B Tempe AZ 85284 Assistant Secretary Sarah Longwell 495 E Rincon, suite 150 Corona CA 92879 President Kathy Cunnington 1130 West Warner Road Building B Tempe AZ 85284 Secretary KATHY C. CUNNINGTON 1130 WEST WARNER ROAD TEMPE AZ 85284 Assistant Secretary Edward Giunta 12911 N Telecom Parkway Tampa FL 33637 Vice President Luc Langevin 12911 N. Telecom Parkway Tampa FL 33637 Vice President Matt Mccure 2440 Whitehall Park Drive Suite 800 Charlotte NC 28273 Vice President David G Morgan 12911 N Telecom Parkway Tampa FL 33637 Vice President Mark Ostoits 2550 West Tyvola road Suite 200 Charlotte NC 28217 Executive Officer Darrell Davis 12911 N. Telecom Parkway Tampa FL 33637 Assistant Secretary Randy Horne 25 W Cedar Street Suite 100 Pensacola FL 32502 Assistant Secretary John Little 305 Gregson Drive Cary NO 27.911 Executive Officer Alex Miller 1130 West Warner Road Building B Tempe AZ 85284 Assistant Secretary Patrick Panzarella 19500 Bulverde Road San Antonio TX 78259 https://www.sosnc.gov/online services/search/]3usiness Registration Results 9/2/2020 North Carolina Secretary of State Search Results Page 3 of 3 Vice President Trey Powell 25W. Cedar Street, Suite 100 Pensacola FL 35202 Vice President Meredith Will Rice , Jr. 1100 Situs Court Suite 100 Raleigh NC 27606 Senior Vice President Vice President Dennis Tewell Tim Tourek 1130 West Warner Road, Building B 255 E.Rincon Suite 100 Tempe AZ 85284 Corona CA 92879 Stock Class: COMMON Shares: 12000000 Par Value 1 Vice President Mark Tate 5500 S Quebec St. Suite 100 Greenwood Village CO 80111 Assistant Secretary Valery Zamuner 4204 Boulevard Industriel Laval XX H7LOE3 https://www.sosnc.gov/online services/search/Business Rcgistration_Results 9/2/2020 Johnson. Ke From: Johnson, Kelly Sent: Thursday, August 27, 2020 12:41 PM To: 'Stephen Ballentine' Cc: Snider, Holley, Hall, Christine; Norris, Kellie E Subject: FW: [External] .054 Airport Blvd - SCM Coordination with NCDEQ Stormwater Express Review Application Questions Attachments: SSW-SWU-101-Application-DEMLR-SPU Oct 2013.doc; Stormwater Supplement - Dry Detention Basin - Phase 3A.xls; O&M Agreement - Dry Pond - Phase 3A.doc; Sheet C2.0 Overall Basin Map ILM Flex Space 2015-07-16.pdf Holley, I believe you are handling wetlands now? Mr. Ballentine needs to impact wetlands at the airport. I do not Know if that would be DWR or the CORPs? See #7 below. If you are not the correct contact, can you please direct him to the appropriate person? Stephen, This is quite a lot of information. It sounds like you want to build a Circle K inside the airport's property and then modify some of the systems under the airport's agreement from years ago. Are you saying that there was a proposed stormwater configuration for Phase 3 and that your proposal will re -design Phase 3? You mention "a portion of Phase 3", so what will happen to the portion of Phase 3 that you aren't changing? I do not know the details of the airport's agreement (and I am not at the office), but I am assuming that the "2 new pre-treatment swales in series with 2 new extended dry detention basins" is an unusual treatment system that that agreement allows. I have cc'd Christine Hall and Kellie Beth Norris who work in the Express Program. They can weigh in on whether or not this would be eligible for Express, as that program doesn't generally review projects with unusual treatment. As for your questions: 1. Application: I have not gone through the details of the attachments, but if you used the "New Permit/ Maw Modification Form" then that is the correct one. You only need one application for the modification regardless of the number of systems that will change. 2. BMP/SCM Checklists: It looks like there used to be a checklist. I do not know what happened to the link. But dry detention with swales isn't a typical treatment system. This is something that they would have negotiated with the airport due to water hazard/bird impacts. There is not a checklist for dry detention. 3. Filter Strip: Again, since this is an unusual design we would have to refer to the agreement or the dry pcnd chapter of the stormwater manual for design guidance. 4. Supplement & O&M Forms: We wound have to go through the file and the agreement and see what the best path is. (The Supplement EZ is intended tc match up with the 2017 rules. I dcr.'t know how that aligns with whatever is required by the agreement in order to guide you on which form malties sense.) I would recommend to submit what you have and the review engineer will have to figure that out. 5. Submlta! List: If your list matches the list on the application then you should be fine. 6. Basin Map: if you have access to the CAD file to update the basin map that would be io4eal. If not, then ave can :update just your phase. But, you will have to be expiicit in explaining hew your protect Nr--sup with the current basin map (especially if you do not replace Phase 3 in full.) 7. Wetlands: Please contact Holley Snider with DWR for wetland questions. You Gviii have t!:) shGw them on the pd an and you will have to get approval to impact them. 8. Review Fee: That is a cuestion for Christine if the project is eligible for Express. Thanks; Kelly ,%_.6L ohvu&ov6 Kelly Johnson Environmental Engineer NC Division of Energy, Mineral and Land Resources Stormwater Permitting 127 Cardinal Drive Extension Wilmington, NC 28405-3845 Phone: 910.796.7335 Note Change in Phone Number D E :. - ue�t�r�en; a,�+�+ariwi aaati�y E-mail correspondence to and from this address may be subject to the North Carolina Public Records Law and may be disclosed to third parties From: Stephen Ballentine [mailto:Stephen.Ballentine@timmons.com] Sent: Thursday, August 27, 2020 10:57 AM To: Johnson, Kelly <kelly.p.johnson@ncdenr.gov> Subject: [External] .054 Airport Blvd - SCM Coordination with NCDEQ Stormwater - Express Review Application Questions emar"t as an attachrnenr to Kelly, Sorry for this long-winded email. We are preparing to make a request for an Express Review. In order to avoid issues during the Express Review, please reply to answer the below questions. Background: This project will include 4 new SCMs: two pre-treatment swales in series with two extended dry detention basins. All SCMs will be located on land, which is owned by New Hanover County, and leased by New Hanover County Airport Authority. These SCMs will not be owned nor operated by Circle K. The applicant will be New Hanover County Airport Authority. These are "regional" stormwater SCMs for the overall New Hanover County Airport Authority development. There will be no subdivision of land with this project, which is a part of the airport. The airport has a very large tract of land, which it leases from the County, with dozens of sub -lessees, such as Circle K, and none of them are subdivided lots. SW8 050547 was approved by NCDEQ and included a Phase 3 expansion of the airport's existing regional extended dry detention basin to the east. However, the basin expansion has not been built to date. Our project proposes to construct 2 new pre-treatment swales in series with 2 new extended dry detention basins, which will provide regional stormwater management for a portion of the previously permitted Phase 3 drainage area of the airport's leased property. This will be a modification of SW8 050547. Please respond to the following questions: • Attached is our single application for a Stormwater Management Permit Application for all 4 proposed SCMs. This will be a modification to SW8 050547. Please reply to confirm that we are using the correct application form, and that only one application is needed for all 4 SCMs. • Section VI of the attached application states that we must include BMP checklists, but the weblink on the form is not valid. Can you please email me the required checklists for an extended dry detention basin and pre- treatment swale? • This project drains to C;Sw waters (Smith Creek) in the Cape Fear Basin. Are we required to provide a filter strip at the outlet of our dry ponds? If yes, then what length? • Is it okay if we submit the attached Stormwater Supplement spreadsheet? Or are we required to submit the "Supplement EZ" document on this website: httys://deg.nc.gov/about/divisions/energy-mineral-and-land-resources/stormwater/stormwater-program/post- construction • Is it okay if we submit the attached 0&M agreement document? Or are we required to submit the "O&M EZ" document on this website: https://deg. nc.gov/about/divisions/energy-m i ne ra I -and -la nd-resources/stormwater/stormwater-program/post- construction • Our package will include the following items. Please let me know if I am missing anything: o (1) original + (1) copy of Stormwater Management Permit Application. o (1) original + (1) copy of signed & notarized Deed Restrictions & Covenants. o (1) original of each SCM supplement form signed/dealed. o (1) signed O&M agreement for each SCM. o (1) check for Express Review (please confirm category and amount). o (1) Express Review Request Form. o (1) Detailed Narrative. o (1) USGS Map. o (1) Stormwater Impact Analysis including calculations. o (2) sets of full sized plans folded to 8.5"x14" o (1) SHWT report o (1) Deed o (1) document indicating that New Hanover County Airport Authority and Circle K are registered with the Secretary of State, including the names and titles of signers. See attached Overall Basin Map, which was part of a 2016 modification to SW8 050547. o Will we be required to include a similar overall basin map with tables in the upper left corner for Phases 1,2,and 3? o Or can we just provide a map showing our Phase 3 area? o Do we also need to tabulate the "Original Permit Conditions" table on our map, as shown on the attached? • Note that there are some existing wetlands on the airport's property, which will be impacted with some of the proposed infrastructure construction. Will this prevent us from obtaining stormwater approval? What do we need to do in regards to wetland impacts prior to Express Review (if anything). • Per the below fee chart... Is this a "Major Modification" with $4,000 Express Review Fee? Or a "Minor Modification" with $1,500 Express Review Fee? Do we just need one single check? IR 6ae _�.�► 9M . 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Stephen Ballentine, PE Project Manager TIMMONS GROUP I www.timmons.com 5410 Trinity Rd, Suite 102 1 Raleigh, NC 27607 Office: 984.255.2367 1 Fax: 919.859.5663 Cell: 919.812.8887 stephen.ballentine(o-_)timmons.com Your Vision Achieved Through Ours To send me files greater than 20MB click here + v*1.LCsL Lori Dtr. 4 From: Johnson, Kelly <kelly.p.iohnsonP- ncdenr.eov> Sent: Tuesday, March 10, 2020 11:45 AM To: Stephen Ballentine <Stephen.Ballentine@timmons.com> Subject: FW: [External] RE:.054 Airport Blvd - SCM Coordination with NCDEQ Stormwater - Existing Extended Dry Detention Basin constructed in 12-ft deep cut Hi Stephen, I have attached the emais you sent this morning to the thread from last week to keep them ali together. Here are the answers to your questions: The SW8 050547 permit is issued to the New Hanover COUnty Airport Authority. if I remember correctly your project wN be for a gas station (which I assume is a different owner?) i:a, ries? prc,,00sed SLMs will be regional SC'Mls own-ed and a b t^:' .i�. '; n a' t t .��• regional _ t;i o;arrr3t;.d ,�� � :L..v i-ler�v+�,.r ..c.;r�y Aii wa t .,vrthor• tv. he New Fianover Count`.1 .sirpor', Aut' orit- veil! 'Ue the appi?;:art. Circla K is Iot interred tc be dhe app i,_an: of, these regiona! SO/Is for rea sci1 : described. if _ills will be a-rclalem, their oieasa? I_t m- know. None Or' h— 0-he;' orso ex;3riilg i-Listar er!,Ide-- elicomer, S on `."re 3 i7pjz;res ov"I- al": de' elopi":lt ^t it3` r3��" t0 �e rl :'i;iC�t?r'; ii � Ei? past, because their •rreiect's 'created .;y t;a 3:ri arts reaicn3! SCIINI. Oui' i J 'ct i5 into: ded to bE the 53n-'; Way. - p J- _ Ste P, h en If your project is inside the project area permitted under SW8 050547, then the airport can apply to subdivide their permit to create an offsite lot for the gas station and deed restrict it to a specific amount of impervious. Tile airPort s policy is to not _ iub&vide their crcpertty,-,nhic,, is owrted. by New Hanever County. They sub-4? se prof, rty to dozens of custcmers, such as Circle K. Yes. ^ur project is within the area permitted Ur;der Phase 3 of SWS 050547. SF. are : lany other e:xistirg sub -leased developments, similar to Circle K. Nooe of those prciQcts have-ubdivido ., io*s. - Stephe Then the gas station can apply for an offsite permit to drain to SW8 050547. T c- 'dew -Ha ncver County .'airport Authority is intended to be the aopiic3nt, si:- ce i:hey will be iwr-I ab a� td c pe r iti:,IS tha SC?.Ys. and because the*,; are .,eg era; SC'Ms, w,ii.t° treat s orm-wzter `„o„r tila overall airp,:vq p!,p ra t jus% C rt.!? �+ 4nd s:�'ce pie K does :lot w,,�n t(ie l2tI J 11,4-ii.'1 which tR!a �C ls are 5i+uated.-5tephe What I do not know are the details of the treatment system for SW8 050547 (design storm, treatment system, other limitat°fins, etc.). If anything unusual was permitted under that permit their you would have to fol!ow the terms of whatever was previously decided. Ti.� _ • , _ i�`'tf'i;r.+rr� �c1_i:"' �', r-�-'-_...'!';'�f�i�L.?`�ti7Ui[: :C7 atdJ::C�:itiS`-'ft�[ rub him I��EiN a' - ._.7 fast ;)t�%,._ County ..P�r:. .ri, JAi: ch NI.. E approved b-�,k ir20wl ..,o.a:: �r- ` ,-er`- ? 5 jll: r; r. air:. fir+ "3r _ '.v 1ro ':i :'.-ti eat i .',^ial C 'o ser' 's v,.,it e;�'�.•' i•-ded' t' n 11.'Ii.. it iEi. l a "i n a $' •a ei't:i.^. N-- � ry Ur_ t� t I t 1 i `ipco,- 'af' reg "i and ;a they i,L�4:LI iC.'tlii'.1:. '••i'J J., �r� 'Nli.'e`+ lira �,",�•tC:`i�' .i =t;�• .1:... ':tS "�it-^_. are �.l. 1 A t(' due- T,ii ��,� S�. e�'�V .,.,.<i:: _trot i� ki.. f�, �-l1i. c: Li;.. � ,l -ir--- c Hasa +�'. i?Ir.i! .:re a 7Z.C?zan S 3!: 'I !" ' k� a t pl 1 g i � i ,,, P t c "J r rie -. _ � f,. �. - L r 'e CO 1.r ;(.iij_ h [.h ill-..:�l�i'?�'�ici;.. ii��.sif_ !�;n `'s,:...°s..f:q. all..-.si•'r;4"t fi Kelly From: Johnson, Kelly Sent: Thursday, March 5, 2020 4:28 PM To: Stephen Ballentine<Stephen.BallentinePtimmons.cem> Cc: Hall, Christine <ChrisVne.HaII@ncdenr.go},">; Brian Downs <Brian.Dos+rns^timmons.com> Subject: RE: [External] RE:.054 Airport Blvd - SCM Coordination with NCDEQ Stormwater - Existing Extended Dry Detention Basin constructed in 12-ft deep cut Hi Stephen, This is quite a lot of information to review before we get an application in-house. I have not read through it. But, if this is in line with something already approved then just go ahead and submit the application. But, if this is a new system that wasn't covered in the original approval then you will have to demonstrate that it will work. I do not know what the circumstances were for approving the original system or what alternatives were (or could) be used. Kelly From: Stephen Ballentine [ 2i.to:Sterhen.Ballentine@timmons.com Sent: Thursday, March 5, 2020 11:15 AM To: Johnson, Kelly <ke'Iy.p.iohnson@ncc"enr.gov> Cc: Hall, Christine <Christine.HaIIt@ncdenr.gov>; Brian Downs <Brian.Downs@timmons.com> Subject: [External] RE:.054 Airport Blvd - SCM Coordination with NCDEQ Stormwater - Existing Extended Dry Detention Basin constructed in 12-ft deep cut 'Do not --- -open - attachment to 9R Good morning Kelly, Attached is one more piece of background information for you. This is a record drawing/plan of the existing Phase 1 & 2 Extended Dry Detention Basin, located to the southeast of our Circle K site, which provides stormwater management for the majority of the Wilmington International Airport's built -upon area. Notice how the north end of this basin was constructed in an area with as deed as 12-feet of cut (presumably below the SHWT). What we are requesting with our Phase 3 basin is consistent with what NCDEQ previously approved within Phases 1 & 2. The airport's property is large and flat, and NCDEQ was flexible with the airport's design approach with this existing basin. Regards, Stephen Ballentine, PE Project Manager TIMMONS GROUP I www.timmons.com [nam03.safelinks.t)rotection.outlgok.comj 5410 Trinity Rd, Suite 102 1 Raleigh, NC 27607 Office: 984.255.2367 1 Fax: 919.859.5663 Cell: 919.812.8887 stephen. ballentine(c),ti mmons.com Your Vision Achieved Through Ours To send me files greater than 20MB click hereInam03.safelinks.prctectio-ri.outlook.comI From: Stephen Ballentine Sent: Thursday, March 5, 2020 11:02 AM To: Johnson, Kelly <kelly.p.iohnson@ncdenr.sov> Cc: Hall, Christine <Christine.Hall@ncdenr.eov>; Brian Downs <Brian.Downs@timmons.com> Subject: RE:.054 Airport Blvd - SCM Coordination with NCDEQ Stormwater - Pre -Treatment Swales Design Criteria Kelly, Please refer to the attached items: Previously approved Pretreatment Grass Swales Sheet C3.0. o This plan shows that two 150-LF grass swales were constructed in areas of 10-ft deep excavation (presumably below the SHWT) for the Phase 1 and Phase 2 drainage areas. o Question: Our proposed Phase 3 with Circle K intends to provide similar grass pre-treatment swales (150 LF and below SHWT) as the existing Phase 1&2 swales described above. Please reply to let us know if this approach will be acceptable in order to meet NCDEQ's requirements for the grass pre-treatment swales for Phase 3. • Total Proposed Grass Swale Length = 150' • Proposed Grass Swales constructed in areas of excavation (likely below SHWT). Regards, Stephen Ballentine, PE Project Manager TIMMONS GROUP I www.timmons.com [nam03.safelinks. protection. outlook. corn] 5410 Trinity Rd, Suite 102 1 Raleigh, NC 27607 Office: 984.255.2367 1 Fax: 919.859.5663 Cell: 919.812.8887 stephen. ballentine(dtimmons.com Your Vision Achieved Through Ours To send me files greater than 20MB click here [nam03.safelinks.protection.outlook.comI From: Stephen Ballentine Sent: Thursday, March 5, 202010:44 AM To: Johnson, Kelly <keiiy.p.iohnson(c@ncdenr.eov> Cc: Hall, Christine <Christine.Hall@ncdenr.eov>; Brian Downs <Brian.Downs@timmons.com> Subject:.054 Airport Blvd - SCM Coordination with NCDEQ Stormwater Kelly, See attached previously approved stormwater permitting items for your reference: • SW8 050547 approved modification including Phase 3 drainage area. o Phases 1, 2, & 3 drainage areas of the airport property are approved for high density. Refer to the tables on page 8 of the attached permit for the BUA area allowances for each phase. • Approved Phase 3 Extended Dry Detention Basin Modification Plan • DA Map showing Phase 3 drainage area and our proposed Circle K site. Our Circle K project is located within the "Phase 3" drainage area of the airport. See attached SW8 050547 modification, which NCDEQ approved in 2011. See attached Phase 3 modification of the existing extended dry detention basin, which was approved, but the Phase 3 expansion of the existing basin to the east of our site was not built. Our project would be submitting a modification to SW8 050547, which would include the construction of a new Phase 3 extended dry detention basin and pre-treatment grass swales located in the southwest corner of the Phase 3 drainage area. Due to the existing flat topography, the extended dry detention basin and the grass swales would need to be in areas of cut, and could be below the SHWT. (This is similar to SCMs, which NCDEQ previously approved in Phases 1 & 2 with the existing grass swales and existing dry basin to the east.) NCDEQ approved the Airport's Stormwater Master Plan with alternative measures to allow the airport flexibility to achieve their goals. The airport's existing dry basin was constructed in a deep cut, which likely encroached into the SHWT in areas. We are asking NCDEQto show us the same flexibility with our SCM design, and to allow the same type of alternative measures, which NCDEQ previously approved with Phases 1 & 2, including grass swales and extended dry detention basins in deep cuts, which may be below the SHWT. We would like to have you onboard with the above issues before we proceed with our full design & submittal. I am available via email or phone. Thanks for your assistance. Regards, Stephen Ballentine, PE Project Manager TIMMONS GROUP I www.timmons.com fnam03.safelinks.Protection, outlook. coml 5410 Trinity Rd, Suite 102 1 Raleigh, NC 27607 Office: 984.255.2367 1 Fax: 919.859.5663 Cell: 919.812.8887 stephen. ballentineCcr�.timmons.com Your Vision Achieved Through Ours To send me files greater than 20MB click here[nam03.safelinE,s.protection.outloo!t.comI From: Johnson, Kelly <kelly.p.iohnson@ncdenr.gov> Sent: Thursday, March 5, 2020 8:59 AM To: Stephen Ballentine<Stephen.Ballentine@timmons.com> Cc: Hall, Christine <Christine.Hall @ncdenr.gov>; Brian Downs <Brian.Downs@timmons.com> Subject: FW: [External] Dry Pond Below SHWT with clay liner Stephen, I issue stormwater permits in the regular program. I am not familiar with this: document. I didn't read it in detail, but a quick skim looks like it was developed to let the airport develop as low density to 30% with pockets of high density. It establishes 13 sub -basins and discusses some specific dry detention systems. Would this be to implement something that has already been approved? Or would this modify something that wGs previously approved? Or wouid it be something completely new? If you are adding impervious will the project remain at/below 30;? Is this inside the original project area of the permit? As for the clay liner question, I have been told by soil scientists over the years that liners do a better joa of keeping water inside a pond than they do keeping water out of a pond. I have been told that the bentonite cracks under the hydraulic pressure of trying to keep water from seeping into a lined system. But, I am not an expert in this department. I think you would have to demons rate that the liner would function indefinitely in the proposed capacity. Also, again, I do not know anything about this permit. (Are we talking about SW8 040836?) We would have to see how that permit is written, what area it covers, etc. As Christine has pointed out, this wouid be a deviation under the current stormwater rules. Kelly From: Hall, Christine Sent: Thursday, March 5, 2020 8:24 AM To: Johnson, Kelly <kelly.P.iohnscn@ncdenr.eov> Subject: FW: [External] Dry Pond Below SHWT with clay liner From: Stephen Ballentine[mailto:Stephen.Ballentine@timmons.coml Sent: Wednesday, March 4, 2020 5:30 PM To: Hall, Christine <Christine.Hall@ncdenr.eov> Cc: Brian Downs <Brian.Downs Cftmmons.com> Subject: RE: [External] Dry Pond Below SHWT with clay liner al email. Do not click links or open attachments unless you verify. Send all suspicious email as an attachment to Christine, Thanks for your message. Please provide me with a name, email, and phone number of someone in the regular stormwater program, who I should discuss this with. The Wilmington International Airport's Stormwater Masterplan was approved back in 2004 with alternative stormwater measures. • Per pages 17 and 18, the following SCMs will be proposed: • Grass pre-treatment swales in series with Extended Dry Detention Basin. This is consistent with the existing stormwater SCM's constructed to serve the overall airport property. Regards, Stephen Ballentine, PE Project Manager TIMMONS GROUP I www.timmons.com[ram03.safelirts.arr,eati-on.outloon.corn? 5410 Trinity Rd, Suite 102 1 Raleigh, NC 27607 Office: 984.255.2367 1 Fax: 919.859.5663 Cell: 919.812.8887 s:aphen. ballentine-5&timmons.com Your Vision Achieved Through Ours Ta send me files greater than 20NTS click here f*tar:z03.safelinics.crotection.:jui;Icok.ccmI 9 From: Hall, Christine <Christine.Hall@ncdenr.gov> Sent: Wednesday, March 4, 2020 5:06 PM To: Stephen Ballentine<Stephen.Ballentine@timmons.com> Subject: RE: [External] Dry Pond Below SHWT with clay liner Stephen, I'm not aware that a dry detention basin is considered to be a primary SCM per 15A NCAC 02H.1002(37). How is the project intending to demonstrate compliance with the stormwater rules? I cannot comment on the acceptability of a clay liner until the full design is presented as part of a submittal package. However, the dry detention basin section of the design manual does net appear to support setting dry detention basins any lower than 6" above the SHWT. 15A NCAC 02H.1003(6) addresses projects that propose any variations from the rules or established minimum design criteria. Please note that projects proposing alternative designs must be submitted to the regular program. The fast track and express programs are net set up for these types of projects. Christine C_il'aif C iit?SpGnCis:'-e toir" f ; ?7 "': i c '!re;3s is SLla G : s� t:'t? �i;o?.f' vA'_;.'"?JOU rtci: ro. A —Y. `c; .:i2✓.,8JtSCrUSeC; From: Stephen Ballentine[mailto:Stephen.Ballentine@timmons.com] Sent: Wednesday, March 4, 2020 2:19 PM To: Hall, Christine <Christine.Hall@rcdenr.gov> Subject: [External] Dry Pond Below SHWT with clay liner External email. Do not click finks or open attachments unless you verify. Send al# suspiciouMail as ailt to Good afternoon Christine, Are you okay with us using an extended dry dentention basin, which is below the SHWT, if we use a clay liner? Thanks, Stephen Ballentine, PE Project Manager TIMMONS GROUP I www.timmons.com [na m03. safelin ks. proecticn.outlook. coml 5410 Trinity Rd, Suite 102 1 Raleigh, NC 27607 Office: 984.255.2367 1 Fax: 919.859.5663 Cell: 919.812.8887 stephen. ballentineCo)-timmons.com Your Vision Achieved Through Ours 10 PIEDM NT ENVIRONMENTAL ASSOC I A T E S° P. A. 7/31/2020 Timmons Group 5410 Trinity Rd., Suite 102 Raleigh, NC 27607 Project # 1775 This report details the findings of a seasonally high-water table evaluation for the Wilmington Airport site in New Hanover County, NC. Your office gave the location of the proposed storm water control measures (SCM) and requested boring locations. G. Christopher Murray, Licensed Soil Scientist #1284, conducted the evaluation on July 27th, 2020. The results were as follows: Seasonally High -Water Table Soil Borings Soil boring were completed within the proposed stormwater control measure at the locations shown on the attached map. The depth to the seasonally high-water table (SHWT) was determined by observing soil indicators, also known as redoximorphic features. Boring 1: Signs of a seasonally high-water table were observed from 8 inches to 120 inches. The native elevation at our boring location was approximately 22'. Boring 2: Signs of a seasonally high-water table were observed from 10 inches to 120 inches. The native elevation at our boring location was approximately 23'. Boring 3: Signs of a seasonally high-water table were observed from 12 inches to 120 inches. The native elevation at our boring location was approximately 23'. Boring ID SHWT Depth inches SHWT Elevation feet 1 ' 8-120 21.3-12 2 10-120 22.2-13 3 12-120 22-13 216 S. Swing Rd., Suite 1 Greensboro, NC 27409 336-662-5487 I,- Piedmont Environmental Associates, PA is pleased to perform this work for you. If you have any questions, please feel free to call (336) 662-5487. Sincerely, G. Christopher Murray N.C. Licensed Soil Scientist #1284 k1l Timmons Group - Wilmington Airport Project (TG 37630.054) PIEDMONT Job#:1775 EN V'�i RON u N TILL 216 S. Swing Rd. Suite 1 Date: 7/31120 ASSOCIATES, P. A Greensboro, NC 27409 Client: Timmons Group I *Vpiedmontsoil.com County: New Hanover - � - � - - � .. � ` y. - - � � .. � � � � •- mar �. k A ilk _- - OP He, H-&&�7 s, 4 �. -1. rF, X 4 :r = :. Legend ® Boring Locations 123� TALBERT & BRIGHT Jul. 2 0 2020 July 20, 2020 Mr. Garrett Zorda NC Department of Environmental Quality Division of Energy, Mineral and Land Resources Wilmington Regional Office 127 Cardinal Drive Ext, Wilmington, NC 28405 RE: Wilmington International Airport Air Carrier Apron Expansion Phase 1 Stormwater Project No. SW8 050547 TBI No. 3301-1702 Dear Mr. Zorda: This follow up provides response to the stormwater review/comments included in the letter dated July 17, 2020. The comments are addressed below. Comment 1. 15A NCAC 02H.1042(2)(a)(iv): In an effort to better document the complete approved design condition and prevent future disconnect between the "Phase I & II" condition and the "Overall" condition, please update the table in Section V.10 of the submitted application and plan sheet C1 to include a fourth column for the "Future Phase III", as represented in the provided "Overall Basin Map" plan sheet. Please also provide an electronic copy of this table so that it can be included as an attachment to the issued permit. Response Plan sheet C1 and the table inform SWU-101, Section IV.10. have been updated to include "Future Phase Ill". An electronic copy of the updated table was sent via email on July 17, 2020 to your email address, garrett.zordo@ncdenr.gov. Attached are revised plan sheet C1 and updated page 3 of form SWU-101. Comment 2. 15A NCAC 02H.1042(2)(g)(iii): Please provide the boundaries of all surface waters, wetlands, regulatory flood zones, protected vegetated setbacks, and protected riparian buffers, or a note on the plans that none exist. If a note is already provided on the plans, please provide a citation of where it can be located. Response The note at the bottom of plan sheet C1 has been revised to state, "No surface waters, wetlands, regulatory flood zones, protected vegetated setbacks, or protected riparian buffers exist." Attached is revised plan sheet C1. ENGINEERING & PLANNING CONSULTANTS 4810 SHELLEY DRIVE WILMINGTON, NC 28405 910.763.5350 FAX 910.762.6281 TALBERT & BRIGHT Comment 3. 15A NCAC 02H.1050(7): Every SCM impacted by sedimentation and erosion control during the construction phase shall be cleaned out and converted to its approved design state. Please provide a note on the plans for this issue. Response A note (note 17) on plan sheet ESC3 has been added to state, "Once construction is complete and the site is stabilized, the Contractor shall be responsible to clean out the newly constructed treatment swale and existing basin, and convert them to their approved design state." Attached is revised plan sheet ESC3. If you should have any further questions, please call. Sincerely, tAcc.,j Ray Marconi, PE Enclosures: (Revised Plan Sheets C1 and ESC3, updated table on page 3 of Form SWU-101, Section IV. 10.) C: Mr. Granseur Dick, PE, CM ENGINEERING & PLANNING CONSULTANTS 4810 SHELLEY DRIVE WILMINGTON, NC 28405 910.763.5350 FAX 910.762.6281 ROY COOPER. ;.;0 iivil(MAEL S. REGAN s~ y BRIAN WRENN DOW1w July 17, 2020 Via email only: gdicJi(a�,flyilm.com New Hanover County Airport Authority Attn: Granseur Dick, PE, Facilities Director 1740 Airport Boulevard, Suite 12 Wilmington, NC 28405 NORTH i.AROUNA ;Ei na"W QK0* Subject: Request for Additional Information Stormwater Project No. SW8 050547 Wilmington International Airport EDDB New Hanover County Dear Mr. Dick: The Wilmington Regional Office received and accepted a modified State Stormwater Management Permit Application for the subject project on April 21, 2020. A preliminary in-depth review of that information has determined that the application is not complete and that additional information is needed. To continue the review, please provide the following additional information in a single, hard cony submittal package: 15A NCAC 02H.1042(2)(a)(iv): In an effort to better document the complete approved design condition and prevent future disconnect between the "Phase I & 11" condition and the "Overall" condition, please update the table in Section V.10 of the submitted application and plan sheet C 1 to include a fourth column for the "Future Phase III", as represented in the provided "Overall Basin Map" plan sheet. Please also provide an electronic copy of this table so that it can be included as an attachment to the issued permit. 2. 15A NCAC 02H.1042(2)(g)(iii): Please provide the boundaries of all surface waters, wetlands, regulatory flood zones, protected vegetated setbacks, and protected riparian buffers, or a note on the plans that none exist. If a note is already provided on the plans, please provide a citation of where it can be located. 3. 15A NCAC 02H.1050(7): Every SCM impacted by sedimentation and erosion control during the construction phase shall be cleaned out and converted to its approved design state. Please provide a note on the plans for this issue. Please remember to confirm that any revised information is presented consistently throughout the application documents including calculations, supplements, narrative, and plans. Please also remember to provide two hard copies of any updated documents per 15A NCAC 02H.1042(2). All of the requested information listed above should be received in this Office by August 3, 2020, or the application will be returned as incomplete. If additional time is needed to submit the requested information, please email your extension requestyrior to this due date to the email address provided below with a justification and a date of when the requested information will be submitted, which shall be no later than 15 days past the original due date. Please note that only two letters requesting additional information is allowed in the State Stormwater Program for a total of 30 days to submit the requested additional information. If the information is not satisfactorily provided after either the second request or 30 days, the project will be returned. If the project is returned and you wish to re -submit later, you will need to resubmit all required items at that time, including the application fee. The construction of any impervious surfaces, other than a construction entrance under an approved Sedimentation Erosion Control Plan, is a violation ofNCGS 143-215.1 and is subject to enforcement action pursuant to NCGS 143-215.6A. NtM'L}l Ca"+.d''o� _"art111fRt at F_-"OY11S1L'f31J( amft'Fi DmBiafl :.)f;r'71Ci* ~oi:xl�K�f and Resewri, $ 4VYlmingtcfn i i,�t`�:r Q. iardlrk)t "Drive Eversion Wlhnaryyr�+� .ticortn�a roiaw �IS�U"+ >�� ��➢G!Almai Yua4� a�1'� '�'l�M.q=.'I.f.. State Stormwater Permit No. SW8 050547 Page 2 of 2 Please reference the State assigned project number on all correspondence. If you have any questions concerning this matter, please feel free to call me at (910) 796-7215 or email me at garrett.zorda@ncdenr.gov. Sincerely, V4ne& 5nd4 Garrett Zorda Environmental Engineer DES/gdz: 111Stormwater\Permits & Projects120051050547 HD12020 07 addinfo 050547 cc: Ramon Marconi, PE, Talbert & Bright, Inc.; via email: rmarconi@tbiilm.com Wilmington Regional Office Stormwater File Zorda, Garrett D From: Zorda, Garrett D Sent: Friday, July 17, 2020 11:50 AM To: gdick@flyilm.com; Ray Marconi Subject: Wilmington International Airport (SW8 050547) - Request for Additional Information Attachments: 2020 07 addinfo 050547.pdf All, Attached is a pdf of the request for additional information for the subject project. There are just a few items that need to be addressed. Please let me know if you have any questions or concerns. Thanks, Garrett Zorda Environmental Engineer Division of Energy, Mineral and Land Resources — State Stormwater Program Department of Environmental Quality 910 796 7215 office 910 796 7343 direct "Please note the change to my direct phone number"" garrett.zorda4mcdenr. ov 127 Cardinal Drive Ext. Wilmington, NC 28405 01MINIMW oft �'Ilw Zorda, Garrett D From: Zorda, Garrett D Sent: Wednesday, July 8, 2020 11:20 AM To: Christine Hall (Christine.Hall@ncdenr.gov) Subject: Airport "overland stormwater flow" - G.S. 143-214.7(c4) Good Morning Christine, I am reviewing the modification for ILM Airport (SW8 050547) and just want to get some clarification so I can better understand if what they are proposing meets the rules or not. This modification proposed two areas of the air carrier apron where the aircraft maneuver and park. The first, larger expansion, is being collected (along with some of the existing apron) and directed to a new proposed treatment swale that leads to a dry basin. The second area (which is on the other side of the apron from the first area) proposes to add 9,268 sf of BUA, but they are claiming that "As previously discussed, this area has "overland stormwater flow" that meets the N.C.G.S 143-214.7(c4) criteria and no further treatment is necessary." The "As previously discussed" refers to a scoping meeting Linda had with them on May 21, 2019. 1 tried to find notes or something from that meeting in the file, but did not find anything. The proposed second area in question does drain to a grassed area for roughly 180' before it goes into an existing drop inlet. I believe this drop inlet currently directs runoff under the taxiway and runway to further grassed areas, although I am still trying to confirm that on older plans. If that can be confirmed, and it isn't directed to an existing system, it appears that they would meet that statute, but I do not have any experience with approving this statute, so I was hoping to get a little more insight on this statute, its applicability, etc. before proceeding. I checked the clarification documents and did not find any relevant information. I am pretty deep in the weeds with this project and just want to make sure I am not heading down a rabbit hole. Any information you can share would be much appreciated. Thanks, Garrett Zorda Environmental Engineer Division of Energy, Mineral and Land Resources State Stormwater Program Department of Environmental Quality 910 796 7215 office 910 796 7343 direct *"Please note the change to my direct phone number"* garrett.zordaftncdenr.aov 127 Cardinal Drive Ext. Wilmington, NC 28405 E.rri3i% i:{,'... '' s1r;G`N; �Wt== cC' of7C1 7 !?? tili,y fs iubject to the !'JOrth f�afi7S`1f7: bfic ��e.'�=•f'r iaL' i�litl may beC7ltiGl[i,S if third i r/ !v'S. Burd, Tina J From: Burd, Tina J Sent: Friday, April 24, 2020 10:18 AM To: gdick@flyilm.com; rmarconi@tbiilm.com Subject: SW8 050547 - Air Carrier Apron Expansion Phase I at Wilmington International Airport The Wilmington Regional Office of the Division of Energy, Mineral and Land Resources (Stormwater Section) accepted the Stormwater Permit Application and $505.00 fee for the subject project on April 21, 2020. The project has been assigned to Garrett Zorda and you will be notified if additional information is needed. Please be advised that the construction of built -upon area may not commence until the Stormwater Permit is issued. Best Regards, Tina Burd Administrative Associate II Wilmington Regional Office Division of Environmental Assistance & Customer Service Phone 910-796-7215 NCDEQ Wilmington Regional Office 127 CardinaR Drive Ext. Wilmington, NC 28405 Application Completeness Review Checklist (Non -Transfers) - Short Version Project Name: W a , Ale-r _ Date Dei:vered to WIRO: r zi c Project County/'Location: mc-,J Aq ooy E d,�� M _ SIMS Receiven!Accep,ed Date. Fiuie(s): ❑?_017 Coasts' ❑2D08 Coastal ®1995 Coastai SIMS Acknowledged Date:: Phase II Universal F-11988 Coastal Permit Action: New Major Mod Minor Mod Renewal Permit Type HD LD j l_D Overa+l / !D &LD Come;o New Permit #2: Existing Permit #:: 7 Expriation Date: lr, 15 Z7 General Permit / Offsne / Exempt / Rescission DOffsite to 5W8: Development Type: Commercial / Residential / Other IndElnt is in Maste' PerrnitP Subdivided;: Subdivision or Single Lot r•}Yi4 EIPE Cert on File? Peermrttee Type & Documents Needed: jPropertu Owner(s) M Purchaser El Lessee `viable? D iab+e? Viable? Deed 0 Purchase Agmt Lease Not Subdivided: 'Deed Flu`id.vision Cornrnon Area Deed Paperwork Application 1:1110-4 FiDeveloper ❑!'iaaie? Fiviaaie? Election Minutes [$50S (within 6mo) Check#(s): [ - (, J 7 supplement (I new form or for older forms: 1 original per SCM) InSoiIs Report (lnfil or PP) k2jCairulations (signed/sealed) Deed Restrictions, if subdivided ®Project Narrative USGS Map (or on fily) Subject to SA?: Y CN Subject to ORW?- Plans (2 Sets) FIPE Certification Electronic Copies Easements, Recorded l2017 Rules) NOTES: 'Enter B I M 5 Acknowledged Date on this Sheet 2For New Projects -Enter New Permit # on Supplements & Deed Restiction Templates. 3If w/in 6 months and they are requesting a rnod, STOP. Needs a renewal first. EMAILED ENGINEER DATE: Comments: REVIEWER NAME: C7 or 1>.� WG.•,,,Rererence-ibrary\Pr• cecures\C`+ecklist5l0omple?eness Review Checklist 2020 02 31 DNo Fee Y/C� TALBERT & BRIGHT, INC. ENGINEERING & PLANNING CONSULTANTS LETTER OF TRANSMITTAL To: NC Division of Environmental Quality Land Resources 127 Cardinal Drive Ext, Wilmington, NC 28405 Date: 4/21/20 Pro'. No. 3301-1702 Attention: Garrett Zorda Re: Wilmington International Airport Air Carrier Apron Expansion Phase 1 Stormwater Permit Modification — Permit No. SW8 050547 WE ARE SENDING YOU: ® Attached ❑ Under Separate Cover via ❑ Shop Drawings ❑ Prints ® Plans ❑ Copy of Letter ❑ Change Order ❑ Other the following items: ❑ Specifications ITEM DATE NO. DESCRIPTION 2 Stormwater Management Permit Application - SW8 050547 1 Original & 1 co 2 Operation & Maintenance Agreement 2 Originals) ., r� 2 Supplement EZ form 2 Originals) 2 Narrative with Impervious and Swale Calculations R 2 1 2020 0 2 Phase I Drainage Area Revised Boundary _ 2 Full Size Plan Sheets Al, A2, A4, A5, C1, SC1, EX1, EX2, EX3, G1, G2, G3, G5, ESC1, ESC2, ESC3, ESC4, D1, D3, D4, D5, P1, X3 1 $505 Check for Permit Fee Check No.: 66773 THESE ARE TRANSMITTED, as checked below: ® For Approval ❑ ❑ For your Use ❑ ❑ For Review and Comment ❑ ❑ As Requested ❑ ❑ FOR BIDS DUE ON REMARKS No Exception taken Make Corrections Noted Amend and Resubmit Rejected — See Remarks ❑ Resubmit Copies for Approval ❑ Submit Copies for Distribution ❑ Return Corrected Prints ❑ Prints Returned After Loan to Us ❑ Other .fir........._. _ COPY TO Granseur Dick, PE (half size plan sheets) SIGNED Ray Marconi, PE ENGINEERING & PLANNING CONSULTANTS 4810 Shelley Drive Wilmington, NC 28405 910.763.5350 FAX 910.762.6281 Jvtz APR 71 2020 BY• Stormwater Narrative Wilmington international Airport Wilmington, North Carolina Air Carrier Apron Expansion Phase I December 5, 2019 G A Roo 6,., SEA►- . 034503 ' \ 1 OV �gJ'••FNG1N��••' G� 'i '••...»...• `� 111111111,,>I00%1` The project involves the expansion of the Air Carrier Apron at Wilmington International Airport (ILM). The primary expansion (Area 1 & 1A) is on the southwest side of the existing apron. This expansion is intended to provide aircraft maneuvering and parking space associated with the expanded hold room and new boarding gates. The secondary area (Add Alternate - Area 2) is a small apron expansion at the southeast corner of the existing apron, intended to ease aircraft maneuvering constraints at existing boarding gates. This project with the proposed stormwater treatment concepts was discussed during a scoping meeting with Linda Lewis on May 21, 2019. The Air Carrier Apron Expansion project will involve a net increase of impervious surfacing on the airfield. Currently, the site drains toward to Smith Creek without treatment. The project drainage design is to include new storm drainage inlets and pipes, conveying the runoff to a new pre-treatment swale, then to the existing forebay area of the airport's Extended Dry Detention Basin No. 1 facility (Permit No. SW8 050547). The basin has been previously sized and permitted for future allocations. This development will utilize 224,192 sf of that future BUA allocation. Prior to directing the runoff to the existing Extended Dry Detention Basin, the runoff must be treated through an additional SCM to achieve the required pollutant removal. A new pre- treatment swale (Pre -Treatment Swale #3) has been designed to accommodate this project and future development. The overall design capacity for the new swale is 696,690 sf (16.0 ac) with 522,720 sf (12.0 ac) of Built Upon Area. This development will utilize 224,192 sf of the 522,720 sf BUA allocation. 113,433 sf of the 224,192 sf is existing BUA that is currently not being treated. Based on the approved permit SW8 050547, a portion of this project's proposed drainage area is outside the 'overall basin map'. The overall basin drainage map has been revised to include the portion of the project currently not included and remove other areas to offset the =� difference. The overall drainage area and impervious totals from permit SW8 050547 will remain the same. z. The secondary area (Add Alternate - Area 2) at the southeast corner of the existing apron has net increase of 9,268 sf. As previously discussed, this area has "overland stormwater flow' at meets the N.C.G.S. 143-214.7(c4) criteria and no further treatment is necessary. A revised Overall Basin Map and Swale Calculations (0.75 in/hr, 10-yr, & 100-yr) are attached. Wilmington International Airport Air Carrier Apron Expansion Phase I 1 {SGS U.S. NEUARTMS. EOLOGICAL SURYNTEFr..� ,�y Nrrh EY CASTLE HKYNE QUADRANGLE mY�rm.r..y.mM 7i 0S Topo MOM CMROLINA 7."NO,E SENES _ i S4'9P le ..' C.U.S ' fts Oil a. V''` -,Corn 9 /'�sU'vlTri YQ \ �•^ -. 1°� - . '• !! iS Project Location y ■ m 1 R � ' < -• �,\ 'mod+ ? zY rA I x vNyrLNNhGTON- a �� I• ,r..,., ... rlrw.• °°° y w,m,' 74 -'�y 'ryp.. wEq�wuneu cweyMr sum.y eau.."m;.".myNn�.1�yum SCALE 7:24000 MD u.\Mrnmox •••--• m.M 4wM ,m.yu.n�mirNi, u m son.,o�b"ium:r mm+.lwf lalfawm� s Mmebuw�,u�Y, mwuNNm �pwmen� w6 V ~ uMw '—r NEI`Y `nen. �, miwu O.n wa`w°ru wm. . .............. _.. _. _...... %m C,- weYxN._..._.rxY I.wo I�x t��s� wmuf lK<NnvAYUN. mI,. �rmnere mbml Wererm Iwsar ,WI - N,1 r mryuruMnoen0.0.0 �r�rern CASTLE NAYNE. NC y �z ems �:3 z H �L£ 0869fiLE O11�58L£ ObF56(6 n�xxic p� M,AE ,bS alz t6 c 0 U d L O co 0 �a Z Q c Cc y p O N U m x Ew o � o m c O = o CD Os Q 2 0 m AS OS oLL m co Q1 � O � N Z co cO cn Z 0 0 � Y o CO a k2 U � m o � Z Od 3 C a 5 SO 7d y .Z 0. O n � o o ` d 3 � zQ zv � M,95 ,M oLL 34° 1610'N 34' 15 50' N 3 Soil Map —New Hanover County, North Carolina 3 Wilmington International Airport Area 2 Air Carrier Apron Expansion Phase I 232090 232160 232230 232300 23ZM 3 Map Scale:1:3,000 if printed on A parbat (8.5" x 1V) sheet N 0 40 80 160 240 A 0 100 200 400 6 r p pr : Web Mercator Comer000rdinates: WGS84 Edge tics: UTM Zone 18N WGS84 US Natural Resources Web Soil Survey Conservation Service National Cooperative Soil Survey 34° 16 10'N I ro n `o y� d i 34' 19 SW 232440 232510 3 12/5/2019 Page 2 of 3 n E U m L 7 N O a H co L - a N O � � w w U N O o, U E C C.)l0 fC ai 'a m .. y E y C U) 01 d o f0 f0 n p c a U (6 L d > L o C G>) d a a'mo07 O O d a a c ma aB, 10 L L W [01 w E„ m E tm: rn g o C N N fA CD E o) c ma �in C o n N s`p C 0) d C N >7 W E�coiw O d m m > Z `d -P m y 1 o c N o oa L y E m y N yo`or o` E U da y 4= C o n c E -Y d 0 o ti 0)) m cu cdi U E c� y m 0 d co ao w a o ai w U o o d 41 ti La) fq d C.0 C f0 d O y> a Z Z O L E y •� p � y 7 N C� d t - d E E U W C d m o d .omnL�° � m m . cowo y o a) oow� cl) a)m c) o Q>, a)7 V � O d w o d� d O Ra aE E d o ix 2 a p d N O y O` y o a „ a c N d o a am)E m'O d N y .O o Uodop Z O U -6 -po =� �i d n2yp N p 'lj f°� f/J y n C �Q Z a o zo rnm id m °' E `o rnaai o oca c °T) N mz m m m wa U c Q`� w m CL oa i0 m >, d d E p w U d C O f0 E C fC � C) 7 �n >� NC d 7 0 d L C tnq E co C w O U N f0 O> CL > T d � cc)n y 'C Of N - N `p N 'd„ 0 V y w = 2 � n N N N a E (��U o''aaQ m IL- o co u)- ON FL- coi E y w m w � c m m m LL U t •� a E ui v c m M = w w m w v o Q m q o o°CL a O .2fn U) cn _ U N CL co fn {O+ w m J 9 Q • ;�� W y LL yq L a C 7 co yH 7 HC m en C CL m o 0.a .J a N E CL c > > 7 a m - y 3 W C7 °w "o a w CL o a n a m 3 fl o a a_ o o a m = m to >, d a W Yw 'o '� '� [L O O UJ N > N > = 'o LL = {p LA O C_ N E Y O T L O Y O •O d a 03 co N C O d m m U O U U' J {>�Qp m J �2 N d O d` W co w N N co C N (A O U) C O Y co ,dzi N. �'. 1 ' 0 � "� of a O w Y rq O O N co d N O) Co EL to m z TBI No.: 3301-1702 Wilmington International Airport Air Carrier Apron Expansion Phase 1 December 5, 2019 Areas and Weighted C Pre Built Upon Area in Drainage Drainage Drainage Percent of Weighted Inlet ID Area ID Area Area BUA C See Note E1 Pre 1 218,538 sf 30,944 sf 14.16% 0.26 See Note E7 Pre 2 50,936 sf 30,259 sf 59.41% 0.63 See Note E4 Pre 3 51,723 sf 51,723 sf 100.00% 0.95 See Note NA Pre 4 321,335 sf 11,842 sf 3.69% 0.18 Overall Total 642,532 sf 124,768 sf 19.42% 0.31 Note: Existing Drainage Area currently does not outfall to existing Basin C Number Sandy Soils Percent of Drainage Area 100% Rooftops and pavement 0.95 Lawns, sandy soil, average (2-7%) 0.15 J:\3301 (Wilmington)\1702 Air Carrier Apron Expansion -Phase I\Permits\NCDEQSW\ Areas.xlsx areas 19 1205 SW z Oa om Q _Z LLI CC ~ Q X W W QD Z f� 0 Q Z) z Z O F-N� — OXO Z LLI Z It W n oz C9 Z 0 � z Cn o w Q R Z ca wF� w t. W �, ,t j l Q a T2 LLI C) OQ LQLC) Zwz , XLvd � Lv U w LJ ZJ o frm 0 H dQ O �z U) <0 Qa X Z C) W O= Z_ F- F- Z O CL (/y LJCL Z Q2 ZZO W Z~ fr C) fr Oz Q O� U J_ Q LO ~ W�ILo0 �Nrl)U �Z^Z W O J :2 N PQ EOZZU O � O J 't00 M z TTXS•g ad '6Mp•seaN a6euieja SOZT 61\6UMIULmd1T BMW uolsued,o uade JapJ23 ile ZOZT\(W76) TOM: TBI No.: 3301-1702 Wilmington International Airport Air Carrier Apron Expansion Phase 1 December 5, 2019 Areas and Weighted C Post (Proposed Project) Built Upon Area in Drainage Drainage Drainage Percent of Weighted Inlet ID Area ID Area Area BUA C See Note E1 Post 1 97,317 sf 5,763 sf 5.92% 0.20 See Note E7 Post 2 8,849 sf 1,868 sf 21.11% 0.32 DI P2 Post 8 133,531 sf 3,070 sf 2.30% 0.17 DI E3 Post 5 125,591 sf 125,591 sf 100.00% 0.95 DI E4 Post 3 51,723 sf 51,723 sf 100.00% 0.95 DI P3 Post 7 18,471 sf 2,755 sf 14.92% 0.27 DI E5 Post 6 37,434 sf 37,434 sf 100.00% 0.95 NA Post 4 153,993 sf 3,619 sf 2.35% 0.17 Overall Total 626,909 sf 231,823 sf 36.98% 0.45 Total to Swale & Basin 520,743 sf 224,192 sf 43.05% 0.49 Note: Drainage Area Outfall remains unchanged; Not included in Swale & Basin C Number Sandy Soils Percent of Drainage Area 100% Rooftops and pavement 0.95 Lawns, sandy soil, average (2-7%) 0.15 J:\3301 (Wilmington)\1702 Air Carrier Apron Expansion - Phase I\Permits\NCDEQ Sw\ Areas.xlsx areas 19 1205 SW �- LLJ LLI u, Q �� `� w U) Q J z W0¢ c�Z !' 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P ac t (b ODLLJ Z n, ' z 0 w + F �,• co ~ � r- o w F- I.- O NJ F ww O2w ! 1 0 Q ELHco \` \ 7t,EL 1 J pZ zopg wwLU L €` w _. 0 as W p ww¢� V)afZ 0<0 w IL 0WZ) � a-QFLLI ` w ZJ o Qm a_ z 0 _ V) Q O Q QQ X ZO U W �Z- O W �O a- Q Ld Q2 ZO W� z C) CK 0z CD :2 0 ZJ Q YI I p M Lo L� �LL! - pro �• i� �N�U O }ZIZ � � W p oz Lb �I I� 9 Z LL) �0ZZ [ ¢ aogOU f- �3az iik'Tg isad'6MP*S—V a6eu!eJ0 SOZ1 6i\6u(Ylluuad\i aseyd uasuedxa uade iawe3 -0e ZOLI\(WII) i6EE\: Wilmington International Airport Air Carrier Apron Expansion Phase 1 Areas and Weighted C Max DA for Proposed PreTreatment Swale #3 TBI No.: 3301-1702 December 5, 2019 Maximum Drainage Maximum Built Upon Percent of Weighted Area Area BUA C Maximum Area to Swale 696,960 sf (16.00 ac) 522,720 sf (12.00 ac) 75.00% 0.75 C Number Sandy Soils Percent of Drainage Area 100% Rooftops and pavement 0.95 Lawns, sandy soil, average (2-7%) 0.15 J:\3301 (Wilmington)\1702 Air Carrier Apron Expansion -Phase I\Permits\NCDEQ SW\ Areas.xlsx areas 19 1205 SW LO �! x.' . i \ o Ld C.) Z i j .f C7 Z � j i.� w z of Y w W Z' ;- IL MQOJ � w E-- U)w Qwcn (0 w<U)< �( C) z WWMQ f-z O Ow�v°w CO rf w,.. m nz zoz�r W LLI z ?Ml W W m W J Q � W U) N O L LLI of az< w Q C Ld �Z o �Z) O m ry aQ O of Z V) a0 Q Q Z U W O= Z_ O W �O d= F- a LLJ Z0 W_ Z F- w 0Z Q O= U Z J rT��i n M W'tTMO >m 1 1 P NK)C) yy�� OC)^0 LJ �ZIZ W J c) O cn W a: Z al Le)�LJ CW) O�zom J [� d �dZ TTxS'6 ]sod-j xeW 16mlysewV a6euleJo S6ZT 61\6ugquuad\T aseyd uolsuedxa umde xaweo Ae ZOLT\(W-9) TOM: TBI No.: 3301-1702 Wilmington International Airport Air Carrier Apron Expansion Phase 1 Swale Calculations Max Drainage Area to Proposed PreTreatment Swale #3 Swale dimensions and drainage information Max Drainage Area= 16.00 ac C= 0.75 Base width(b)= 6.0 ft Z = 5.0 d = depth 7.8 ft high= 17.00 ft low= 15.20 ft length= 225 ft Slope(S) = 0.0080 IDEQ 0.75 in/hr Design QDEQ = 9.00 cfs Bermuda Grass d Capacity of Swale 7.80 ft Flow Conditions .47 ft Freeboard 7.33 ft December 5, 2019 A=bd+(zd)^2 P=b+2dx((z)"2+1)^.5 A P R n V Qact Comments 351.00 sf 85.54 ft 4.10 ft 0.030 11.39 fps 3,998.20 cfs Qact>QDEQ OK V<5 fps X 3.96 sf 10.83 ft .37 ft 0.030 2.27 fps 9.00 cfs Qact>QDEQ OK V<5 fps OK 110 7.23 in/hr Design Q10 = 86.76 cfs Bermuda Grass d A P R n V Qa, Comments Capacity of Swale 7.80 ft 351.00 sf 85.54 ft 4.10 ft 0.030 11.39 fps 3,998.20 cfs Qact>Q10 OK V<5 fps X Flow Conditions 1.50 ft 20.21 sf 21.28 ft .95 ft 0.030 4.29 fps 86.76 cfs Qat>Q10 OK V<5 fps OK Freeboard 6.30 ft 1100 9.60 in/hr Design Q100 = 115.20 cfs Bermuda Grass d Capacity of Swale 7.80 ft Flow Conditions 1.71 ft Freeboard 6.09 ft A P R n V Qa« Comments 351.00 sf 85.54 ft 4.10 ft 0.030 11.39 fps 3,998.20 cfs Qact>Q1oo OK V<5 fps X 24.91 sf 23.45 ft 1.06 ft 0.030 4.62 fps 115.20 cfs Qact>Q1oo OK V<5 fps OK J:\3301 (Wilmington)\1702 Air Carrier Apron Expansion - Phase I\PermitsW CDEQ SW\ Swales DEQ SW.xlsx Swale SW Max 1205 19 TBI No.: 3301-1702 Wilmington International Airport Air Carrier Apron Expansion Phase 1 Swale Calculations Current project Drainage Area to Proposed PreTreatment Swale #3 Swale dimensions and drainage information Max Drainage Area= 11.95 ac C= 0.49 Base width(b)= 6.0 ft Z = 5.0 d = depth 7.8 ft high= 17.00 ft low= 15.20 ft length= 225 ft Slope(S) = 0.0080 IDEA 0.75 in/hr Design QDEQ = 4.39 cfs Bermuda Grass d Capacity of Swale 7.80 ft Flow Conditions .32 ft Freeboard 7.48 ft December 5, 2019 A=bd+(zd)^2 P=b+2dx((z)^2+1)^.5 A P R n V Qad Comments 35 1. 00 sf 85.54 ft 4.10 ft 0.030 11.39 fps 3,998.20 cfs Qad>QDEQ OK V<5 fps X 2.42 sf 9.25 ft .26 ft 0.030 1.82 fps 4.39 cfs Qad>QDEQ OK V<5 fps OK 110 7.23 in/hr Design Qlo = 42.35 cfs Bermuda Grass d A P R n V Qact Comments Capacity of Swale 7.80 ft 351.00 sf 85.54 ft 4.10 ft 0.030 11.39 fps 3,998.20 cfs Qad>Qlo OK V<5 fps X Flow Conditions 1.06 ft 11.96 sf 16.80 ft .71 ft 0.030 3.54 fps 42.35 cfs Qad>Qlo OK V<5 fps OK Freeboard 6.74 ft I100 9.60 in/hr Design Q100 = 56.23 cfs Bermuda Grass d Capacity of Swale 7.80 ft Flow Conditions 1.22 ft Freeboard 6.58 ft A P R n V Qad Comments 351.00 sf 85.54 ft 4.10 ft 0.030 11.39 fps 3,998.20 cfs Qact>Q1oo OK V<5 fps X 14.71 sf 18.41 ft .80 ft 0.030 3.82 fps 56.23 cfs Qact>Qloo OK V<5 fps OK J:\3301 (Wilmington)\1702 Air Carrier Apron Expansion - Phase I\Permits\NCDEQ SW\ Swales DEQ SW.xlsx Swale SW Ph 1 1205 19 4 0 Z' 0 <) & lb t-6 0 % - ww-mull 2- at ��w O ca .0 z z 0 U 0 z .0 Aso wz' 4.1 z 2.2 0, -0. Z li 0 Ln af SEAL Cat. DECEMBER 2019 Sd. V— 500' Drawn REM Checked EMS Project No. 3=-1702 500 250 0 500 1000 1500 Sh..t No. SCALE IN FEET 1"= 500' ROY COOPER Governor MICHAEL S. REGAN Secretary BRIAN WRENN Acting Director March 31, 2020 NORTH CAROLINA Enytrww entulQuality New Hanover County Airport Authority Attn: Granseur Dick, Facilities Director 1740 Airport Boulevard, Suite 12 Wilmington, NC 28405 Subject: PROJECT RETURN Stormwater Management Project No. SW8 050547 Wilmington International Airport EDDB New Hanover County Dear Mr. Dick: The Wilmington Regional Office received and accepted a State Stormwater Management Minor Modification Permit Application for the subject project on January 29, 2020. A review of the information submitted with the application indicates that the requested minor modification is increasing the size of the SCM. Any increase In the size of the SCM is considered a major modification to the permit per 15A NCAC 02H.1002(23) and (25). Per the requirements of Title 15A NCAC 02H.1042(3)(a)(ii) of the Stormwater Management Rules, this Office is hereby returning the subject application as incomplete. If you wish to pursue construction of this proposed project, you must reapply to the Division. Your application package must include a completed and signed application form; supplement form; signed O&M agreement; application fee; signed, sealed and dated calculations; and 2 sets of signed, sealed and dated site layout and grading plans with details. Please note that the permit issued on October 3, 2019 remains in full force and effect. Please be aware that the construction of any changes to the originally approved and permitted plans prior to the receipt of a modified permit is a violation of NCGS 143-215.1 and is subject to enforcement action pursuant to NCGS 143-215.6A. If you have any questions concerning this matter, please contact Garrett Zorda at (910) 796-7215 or via e- mail at garrett.zorda@ncdenr.gov. Sincerely, Brian Wrenn, cting Director Division of Energy, Mineral and Land Resources DES/gdz: \\\Stormwater\Permits & Projects\2005\050547 HD\2020 03 return_project 050547 cc: Ramon Marconi, PE, Talbert & Bright, Inc. New Hanover County Building Safety Department. Wilmington Regional Office I North Carolina Department of Environmental Quality I Division of Energy. Nflneral and Land Resources Q. E I Wilmington Regional Office 1 127 Cardinal Drive Extension I Wilmington. North Carolina 28405 NQUaLgaaam °p1b�g°°' \ 401�4 910.796.7215 Zorda, Garrett D From: Zorda, Garrett D Sent: Thursday, March 26, 2020 1:24 PM To: Ray Marconi; gdick@flyilm.com Cc: Sams, Dan Subject: RE: [External] FW: SW8 050547 - Wilmington International Airport EDDB All, I am currently reviewing the subject project, which was submitted as a lhftor Modification. Per 15A NCAC 02H.1002(25), a minor modification is defined as "a change of a state stormwater pel mit that does not increase the net built -upon area within the project or does not increase the ove -all size of the stormwater control measures that have been approved for the project." The submitted application package, however, indicates that a new SCM (Pre -Treatment Swale #3) is being proposed to meet Permit Condition 1.9. Adding this SCM would require this modification to be submitted as a Major Modification, which includes the appropriate application, fee, plans and other supporting documentation as part of a complete major modification package. As such, this minor modification application will need to be returned and a new, complete major modification application package will need to be submitted. Please let me know if you have any questions or concerns. Thanks, Garrett Zorda Environmental Engineer Division of Energy, Mineral and Land Resources — State Stormwater Program Department of Environmental Quality 910 796 7215 office 910 796 7345 direct aarrett.zorda(ci)-ncdenr.aov 127 Cardinal Drive Ext. Wilmington, NC 28405 EmailIl -2t'.0 fr}�ri: t0is c'ClCiio,'*S' iz,, s b';9 t to t7!e fiJ•�r`!,; Carolina i rr. <'t of-d._ L3: 3;:C .,''13`r prU 1=a14i�° From: Ray Marconi [mailto:rmarconi@tbiilm.com] Sent: Tuesday, March 24, 2020 9:03 AM To: Zorda, Garrett D <garrett.zorda@ncdenr.gov> Cc: Eric Stumph <estumph@tbiilm.com> Subject: [External] FW: SW8 050547 - Wilmington International Airport EDDB erria>. Do not click [inks or open attachments urs Garrett, I received an email from Tina stating you were assigned to the Stormwater Review for the Air Carrier Apron Expansion Phase I project at Wilmington International Airport. Given the Airport's more complex stormwater permitting history and multiple permits, a scoping meeting with Linda Lewis was held on May 21, 2019 to review the basic concepts of our proposed development and treatment. We are also the Engineer that developed the Airport's stormwater master plan and assisted with several other permit approvals. If you have any questions, I would be happy to assist. Will you please provide estimated time when you expect to have the review completed? Thank you for your time, Ray Marconi, PE 4810 Shelley Drive Wilmington, NC 28405 (910) 763-5350 / Phone From: Burd, Tina J <Tina.Burd@ncdenr.Gov> Sent: Thursday, February 06, 2020 4:11 PM To: gdick@flyilm.com; Ray Marconi <rmarconi(c@tbiilm.com> Subject: SW8 050547 - Wilmington International Airport EDDB The Wilmington Regional Office of the Division of Energy, Mineral and Land Resources (Stormwater Section) accepted the Stormwater Permit Minor Modification Application for the subject project on January 29, 2020. The project has been assigned to Garrett Zorda and you will be notified if additional information is needed. Please be advised that the construction of built -upon area may not commence until the Stormwater Permit is issued. Best Regards, Tina Burd Administrative Associate II Wilmington Regional Office Division of Environmental Assistance & Customer Service Phone 910-796-7215 NCDEQ Wilmington Regional Office 127 Cardinal Drive Ext. Wilmington, NC 28405 Erm # ,;'J?"-es''?onclr: nog fi .. ;i :"t ! "�:aS 9�t to., t3 North vurC l'IT) t�UrJli � F'_ '7f _ 3l7C7 !" ;;Si t78 C! ��:IiJ;S :s tQ 1:�1 r rJ' iCic^r(V& s. Johnson, Kelly From: Stephen Ballentine<Stephen.Ballentine@timmons.com> Sent: Friday, March 13, 2020 9:06 AM To: Johnson, Kelly Cc: Brian Downs Subject: RE: [External] .054 Circle K Airport Blvd, Wilmington - NCDEQ Stormwater Permit Application Form (SW8 050547) Attachments: Sheet C3.0 Phase 3 Basin Expansion Plan.pdf; SW8 050547 Ph 3 Approved Modification 2011-10-26.pdf; Phases 1 & 2 Dry Pond Sheet P-2 Extended Dry Detention Basin 1.pdf ail, Do not click links or open attachments unless you verify. Send all suspicious email as an attachment to Hi Kelly, See my comments below in green. Thanks, -Stephen From: Johnson, Kelly <kelly.p.johnson@ncdenr.gov> Sent: Wednesday, March 11, 2020 4:29 PM To: Stephen Ballentine <SteDhen.Ballentine &timmons.com> Subject: FW: [External] .054 Circle K Airport Blvd, Wilmington - NCDEQ Stormwater Permit Application Form (SW8 050547) Hi Stephen, I wanted to follow up on our call from yesterday. I read through the information you sent. I think there are three main areas of discussion: Dry Pond #3: It looks like the 2004 Stormwater Master Plan was something negotiated before the first permit was issued in 2005. The State "approved" it in November 2004 and they probably applied for their first permit shortly thereafter. Page 2 of the stormwater plan refers to two basins. The first permit was issued in 2005 and it only has one basin. It appears that they had not designed the second one yet, but that they had envisioned it when they wrote the master plan. Perhaps a third was added later? I know that a single extended dry detention basin was constructed for Phases 1 and 2. See attached PDF plan. (It is possible that there might be another, smaller pond somewhere else on the airport's property, which I am not aware of. However, since it is not near our Circle K drainage area, it should not be relevant to our Circle K project.) -Stephen That could also be why the 2011 version of the permit shows Phase III at 1.5" rather than 1.0" per the 2004 Master Plan? I have not gone through the file carefully enough to determine whether or not there is a permitted dry pond for the Phase III area or the details of that design. Yes. Attached is the Phase 3 approved permit and the construction drawing showing the expansion of the existing Ph 1 & 2 extended dry detention pond to accommodate Phase 3. This phase 3 pond expansion has not been constructed to date. -Stephen From our conversation it seems that there is, and that you want to modify it because a modified one would work better for the location you have decided to build. Our current intent is to not construct the attached Phase 3 expansion of the existing Phase 1 & 2 dry pond. Rather, we intend to construct a new, separate Phase 3 extended dry detention pond. -Stephen The cover page of the 2011 permit says, "The project name is changed to remove the Phase 1, 11 and 111 designation. The phases refer to the construction of the dry detention basin, not to any particular stage of BUA development within the airport. This permit contains design information for the "Phase 1 and 11" dry detention basin serving a 28Z63 acre drainage area and for the "Overall built -out dry detention basin serving a 322.34 acre drainage area." The current (2019) permit only lists two dry basins called "Phase 1 & II" and "Overall". I do not know that there is a designed/permitted third dry pond? Currently, there is not a designed/permitted third extended dry detention pond. However, Timmons Group is designing the separate Phase 3 extended dry detention pond. -Stephen 2. Type of System: Page 16 of the 2004 Stormwater Management Plan says that the airport will use dry ponds (50% TSS) and grass swales (35%TSS) for a total of 85% TSS, as was required by law. This was because many years ago that is how treatment trains were calculated. The goal was to reduce potential issues with birds as discussed on Page 2 of the Plan. Page 18 of the 2004 Stormwater Management Plan says that, "to the extent possible, position the bottom of the basin above the seasonal high water table." Page 25 describes that the plan is conceptual, and that it could be modified over time. Your design can use a dry pond + swale as discussed in the plan, but you would have to demonstrate that if you intercept the water table that you have minimized the impact "to the extent possible". That would mean that you have considered other options that do not intercept the water table such as a larger surface area of dry pond that is more shallow, or a system other than a dry pond that does not have a permanent pool of water. Understood. We will address this in our stormwater report narrative, which we will include with our application. -Stephen Land Ownership: I think this took a turn yesterday because there were so many moving parts. In thinking this through today, if the airport owns the land and they lease land to Circle K, and the airport wants the gas station to fall directly under their permit (SW8050547) as opposed to getting a second permit for the Circle K then there is a way to do that. But, the airport should be aware that if Circle K does not build per this plan that the airport will be the one that would be found in violation and not Circle K. This would become a civil matter between them. So, the airport could apply for a modification to add the Circle K as you have described. Understood/agreed. Circle K will coordinate with the airport as needed on this. -Stephen If you have further questions, please let me know. No further questions at this time. Thank you. -Stephen Thanks, Kelly From: Stephen Ballentine fmailto:Stephen.Ballentine@timmons.com] Sent: Tuesday, March 10, 2020 3:00 PM To: Johnson, Kelly <kelly.p.iohnson@ncdenr.gov> Subject: [External] .054 Circle K Airport Blvd, Wilmington - NCDEQ Stormwater Permit Application Form CAUTION: Good afternoon Kelly, FYI, here is some additional information for you: • The Circle K site, pond site, and surrounding areas are on land owned by New Hanover County, but controlled by Wilmington International Airport. • The land will continue to be owned by New Hanover County. • Circle K will have a lease agreement with New Hanover County and/or the Airport, but Circle K will not actually own land. • The Wilmington International Airport will be the applicant on our NCDEQ Stormwater Permit Application, and the SCMs will be owned and maintained by the airport. These are regional SCM's, which will treat runoff from Circle K and other future developments on the airport controlled land. My understanding is that we will need to submit for a modification of SW8 050547 using Stormwater Management Permit Application Form SWU-101, and that this must be submitted via standard review. https:Hdeg.nc.goy/about/divisions/energy-mineral-and-land-resources/stormwater/stormwater-program/post construction [nam03.safelinks. protection.outlook.coml If you believe otherwise; then nlease let me know. Regards, Stephen Ballentine, PE Project Manager TIMMONS GROUP I www.timmons.com rnam03.safelinks.protection.outlook.comI jnam03. safelin ks. protection. outlook.coml 5410 Trinity Rd, Suite 1021 Raleigh, NC 27607 Office: 984.255.2367 1 Fax: 919.859.5663 Cell: 919.812.8887 stephen.ballentineO-timmons.com Your Vision Achieved Through Ours To send me files greater than 20MB click here [nam03.safelinks.protection.outlook.comI [nam03.safeli nks. protection.outlook.com1 From: Johnson, Kelly <kelly.p.iohnson@ncdenr.gov> Sent: Tuesday, March 10, 202011:45 AM To: Stephen Ballentine <Stephen.Ballentine@timmons.com> Subject: FW: [External] RE:.054 Airport Blvd - SCM Coordination with NCDEQ Stormwater - Existing Extended Dry Detention Basin constructed in 12-ft deep cut Hi Stephen, I have attached the emails you sent this morning to the thread from last week to keep them all together. Here are the answers to your questions: The SW8 050547 permit is issued to the New Hanover County Airport Authority. If I remember correctly your project will be for a gas station (which I assume is a different owner?) If your project is inside the project area permitted under SW8 050547, then the airport can apply to subdivide their permit to create an offsite lot for the gas station and deed restrict it to a specific amount of impervious. Then the gas station can apply for an offsite permit to drain to SW8 050547. What I do not know are the details of the treatment system for SW8 050547 (design storm, treatment system, other limitations, etc.). If anything unusual was permitted under that permit then you would have to follow the terms of whatever was previously decided. Kelly From: Johnson, Kelly Sent: Thursday, March 5, 2020 4:28 PM To: Stephen Ballentine<Stephen.Ballentine@timmons.com> Cc: Hall, Christine <Christine.Hall@ncdenr.eov>; Brian Downs <Brian.Downs@timmons.com> Subject: RE: [External] RE:.054 Airport Blvd - SCM Coordination with NCDEQ Stormwater - Existing Extended Dry Detention Basin constructed in 12-ft deep cut Hi Stephen, This is quite a lot of information to review before we get an application in-house. I have not read through it. But, if this is in line with something already approved then just go ahead and submit the application. But, if this is a new system that wasn't covered in the original approval then you will have to demonstrate that it will work. I do not know what the circumstances were for approving the original system or what alternatives were (or could) be used. Kelly From: Stephen Ballentine [mailto:Stephen.Ballentine@timmons.com] Sent: Thursday, March 5, 202011:15 AM To: Johnson, Kelly <kelly.p.iohnson@ncdenr.eov> Cc: Hall, Christine <Christine.Hall @ncdenr.eov>; Brian Downs <Brian.Downs@timmons.com> Subject: [External] RE:.054 Airport Blvd - SCM Coordination with NCDEQ Stormwater - Existing Extended Dry Detention Basin constructed in 12-ft deep cut • - not click links or open attachments unless you verify. Send all suspicious email as an attachment to Good morning Kelly, Attached is one more piece of background information for you. This is a record drawing/plan of the existing Phase 1 & 2 Extended Dry Detention Basin, located to the southeast of our Circle K site, which provides stormwater management for the majority of the Wilmington International Airport's built -upon area. Notice how the north end of this basin was constructed in an area with as deed as 12--feet of cut (presumably below the SHWT). What we are requesting with our Phase 3 basin is consistent with what NCDEQ previously approved within Phases 1 & 2. The airport's property is large and flat, and NCDEQ was flexible with the airport's design approach with this existing basin. Regards, 4 Stephen Ballentine, PE Project Manager TIMMONS GROUP I www.timmons.com [nam03. safelin ks. protection. outlook. coml [nam03. safelin ks. protection. outlook. coml 5410 Trinity Rd, Suite 102 1 Raleigh, NC 27607 Office: 984.255.23671 Fax: 919.859.5663 Cell: 919.812.8887 stephen.ballentineCcDtimmons.com Your Vision Achieved Through Ours To send me files greater than 20MB click here [na m03.safel inks. Protection.outlook.coml [nam03.safelinks.protection.outlook.com1 From: Stephen Ballentine Sent: Thursday, March 5, 202011:02 AM To: Johnson, Kelly <kellv.p.iohnson@ncdenr.eov> Cc: Hall, Christine <Christine.Hall@ncdenr.eov>; Brian Downs <Brian.Downs@timmons.com> Subject: RE:.054 Airport Blvd - SCM Coordination with NCDEQ Stormwater - Pre -Treatment Swales Design Criteria Kelly, Please refer to the attached items: Previously approved Pretreatment Grass Swales Sheet C3.0. o This plan shows that two 150-LF grass swales were constructed in areas of.10-ft deep excavation (presumably below the SHWT) for the Phase 1 and Phase 2 drainage areas. o Question: Our proposed Phase 3 with Circle K intends to provide similar grass pre-treatment swales (150 LF and below SHWT) as the existing Phase 1&2 swales described above. Please reply to let us know if this approach will be acceptable in order to meet NCDEQ's requirements for the grass pre-treatment swales for Phase 3. • Total Proposed Grass Swale Length =150' • Proposed Grass Swales constructed in areas of excavation (likely below SHWT). Regards, Stephen Ballentine, PE Project Manager TIMMONS GROUP I www.timmons.com rnam03.safelinks. protection. outlook. coml [nam03.safelinks.protection.outlook.comI 5410 Trinity Rd, Suite 102 1 Raleigh, NC 27607 Office: 984:255.2367 1 Fax: 919.859.5663 Cell: 919.812.8887 stephen.ballentineCcDtimmons.com Your Vision Achieved Through Ours To send me files greater than 20MB click here [nam03.safelinks.protection.outlook.com1 [nam03.safelinks.protection.outlook.com1 From:'Stephen Ballentine Sent: Thursday, March 5, 202010:44 AM To: Johnson, Kelly <kelly.p.iohnson@ncdenr.eov> Cc: Hall, Christine <Christine.Hall @ncdenr.eov>; Brian Downs <Brian.Downs@timmons.com> Subject:.054 Airport Blvd - SCM Coordination with NCDEQ Stormwater Kelly, See attached previously approved stormwater permitting items for your reference: • SW8 050547 approved modification including Phase 3 drainage area. o Phases 1, 2, & 3 drainage areas of the airport property are approved for high density. Refer to the tables on page 8 of the attached permit for the BUA area allowances for each phase. • Approved Phase 3 Extended Dry Detention Basin Modification Plan • DA Map showing Phase 3 drainage area and our proposed Circle K site. Our Circle K project is located within the "Phase 3" drainage area of the airport. See attached SW8 050547 modification, which NCDEQ approved in 2011. See attached Phase 3 modification of the existing extended dry detention basin, which was approved, but the Phase 3 expansion of the existing basin to the east of our site was not built. Our project would be submitting a modification to SW8 050547, which would include the construction of a new Phase 3 extended dry detention basin and pre-treatment grass swales located in the southwest corner of the Phase 3 drainage area. Due to the existing flat topography, the extended dry detention basin and the grass swales would need to be in areas of cut, and could be below the SHWT. (This is similar to SCMs, which NCDEQ previously approved in Phases 1 & 2 with the existing grass swales and existing dry basin to the east.) NCDEQ approved the Airport's Stormwater Master Plan with alternative measures to allow the airport flexibility to achieve their goals. The airport's existing dry basin was constructed in a deep cut, which likely encroached into the SHWT in areas. We are asking NCDEQ to show us the same flexibility with our SCM design, and to allow the same type of alternative measures, which NCDEQ previously approved with Phases 1 & 2, including grass swales and extended dry detention basins in deep cuts, which may be below the SHWT. We would like to have you onboard with the above issues before we proceed with our full design & submittal. I am available via email or phone. Thanks for your assistance. Regards, Stephen Ballentine, PE Project Manager TIMMONS GROUP I www.timmons.com [nam03.safelinks.protection.outlook.com1 rnam03.safelinks. protection.outlook.comj 5410 Trinity Rd, Suite 102 1 Raleigh, NC 27607 Office: 984.255.2367 1 Fax: 919.859.5663 Cell: 919.812.8887 stephen.ballentinehtimmons.com Your Vision Achieved Through Ours To send me files greater than 20MB click here [nam03.safelinks.protection.outlook.com1 [nam03.safelinks.protection.outlook.com1 From: Johnson, Kelly <kelly.p.iohnson@ncdenr.eov> Sent: Thursday, March 5, 2020 8:59 AM To: Stephen Ballentine<Stephen.BaIlentine@timmons.com> Cc: Hall, Christine <Christine.Hall @ncdenr.eov>; Brian Downs <Brian.Downs@timmons.com> Subject: FW: [External] Dry Pond Below SHWT with clay liner Stephen, I issue stormwater permits in the regular program. I am not familiar with this document. I didn't read it in detail, but a quick skim looks like it was developed to let the airport develop as low density to 30% with pockets of high density. It establishes 13 sub -basins and discusses some specific dry detention systems. Would this be to implement something that has already been approved? Or would this modify something that was previously approved? Or would it be something completely new? If you are adding impervious will the project remain at/below 30%? Is this inside the original project area of the permit? As for the clay liner question, I have been told by soil scientists over the years that liners do abetter job of keeping water inside a pond than they do keeping water out of a pond. I have been told that the bentonite cracks under the hydraulic pressure of trying to keep water from seeping into a lined system. But, I am not an expert in this department. I think you would have to demonstrate that the liner would function indefinitely in the proposed capacity. Also, again, I do not know anything about this permit. (Are we talking about SW8 040836?) We would have to see how that permit is written, what area it covers, etc. As Christine has pointed out, this would be a deviation under the current stormwater rules. Kelly From: Hall, Christine Sent: Thursday, March 5, 2020 8:24 AM To: Johnson, Kelly <kelly.p.iohnson@ncdenr.eov> Subject: FW: [External] Dry Pond Below SHWT with clay liner Email correspondence to and from this address is subject to the North Carolina Public Records Law and may be disclosed to third parties. From: Stephen Ballentine[mailto:Stephen.Ballentine@timmons.com] Sent: Wednesday, March 4, 2020 5:30 PM To: Hall, Christine <Christine.Hall@ncdenr.eov> Cc: Brian Downs <Brian.Downs@timmons.com> Subject: RE: [External] Dry Pond Below SHWT with clay liner Christine, Thanks for your message. Please provide me with a name, email, and phone number of someone in the regular stormwater program, who I should discuss this with. The Wilmington International Airport's Stormwater Masterplan was approved back in 2004 with alternative stormwater measures. • Per pages 17 and 18, the following SCMs will be proposed: • Grass pre-treatment swales in series with Extended Dry Detention Basin. This is consistent with the existing stormwater SCM's constructed to serve the overall airport property. Regards, Stephen Ballentine, PE Project Manager TIMMONS GROUP I www.timmons.com lnam03.safelinks. protection.outlook.coml Inam03.safelinks.protection.outlook.comI 5410 Trinity Rd, Suite 102 1 Raleigh, NC 27607 Office: 984.255.2367 1 Fax: 919.859.5663 Cell: 919.812.8887 stephen.ballentineO-timmons.com Your Vision Achieved Through Ours To send me files greater than 20MB click here fnam03.safelinks.protection.outlook.com1 Fnam03.safelinks.protection.outlook.comI From: Hall, Christine <Christine.Hall@ncdenr.eov> Sent: Wednesday, March 4, 2020 5:06 PM To: Stephen Ballentine <Stephen.Ballentine@timmons.com> Subject: RE: [External] Dry Pond Below SHWT with clay liner Stephen, I'm not aware that a dry detention basin is considered to be a primary SCM per 15A NCAC 02H.1002(37). How is the project intending to demonstrate compliance with the stormwater rules? I cannot comment on the acceptability of a clay liner until the full design is presented as part of a submittal package. However, the dry detention basin section of the design manual does not appear to support setting dry detention basins any lower than 6" above the SHWT. 15A NCAC 02H.1003(6) addresses projects that propose any variations from the rules or established minimum design criteria. Please note that projects proposing alternative designs must be submitted to the regular program. The fast track and express programs are not set up for these types of projects. Christine Email correspondence to and from this address is subject to the North Carolina Public Records Law and may be disclosed to third parties. From: Stephen Ballentine[mailto:Stephen.Ballentine@timmons.com] Sent: Wednesday, March 4, 2020 2:19 PM To: Hall, Christine <Christine.Hall @ncdenr.eov> Subject: [External] Dry Pond Below SHWT with clay liner CAUTIO ter{ amn�. c Good afternoon Christine, Are you okay with us using an extended dry dentention basin, which is below the SHWT, if we use a clay liner? Thanks, Stephen Ballentine, PE Project Manager TIMMONS GROUP I www.timmons.com fnam03.safelinks. protection. outlook. coml [nam03.safelinks. protection. outlook. corn'! 5410 Trinity Rd, Suite 102 1 Raleigh, NC 27607 Office: 984.255.2367 1 Fax: 919.859.5663 Cell: 919.812.8887 stephen.ballentineO-)timmons.com Your Vision Achieved Through Ours To send me files greater than 20MB click here [nam03.safelinks.protection.outlook.com1 Inam03.safeli nks. protection.outlook.coml 9 SNOISKU AI I 9IMS L 'ON NISVB NOLLN3130 ANO 03ON3.LX3TT****y�7��p►��7 II 3SYHd - LN3vmVNVW M3LVMAd=J.tl Auff v Ma 1 Y �L - ON 'NOONIWO & LL p5 iNDdNltl IVNOLLVNN3lNl NUISNI 1 d111 ^ ��y ¢¢\{t� `\\. 11 \` ♦� � Jill' i �� 8 933� 3 in I-dill"AU0111. --i II XF �111 1r I;lr y� X �O /•\ a+7�jN /ram//� / I • //' ` / / 11 I111 I / \ ��1 I ���^T�UxW <� W ,'I'Ir IIII% 41\ \\- Ilyd l �/� / \ •yi1�1'Iy Illlll y\�I III , l - I 'tk_ •' '''lil�li'�.�`• ii'� // Q • j 1��1,{���u 9 � ��E`,�' �t6 I I I ii Il'I i u' �Yl'\1�yy`\y ' !di �x Ilia ' / ' `\\ \l �. �`•\` %% lI II I� ( ! 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Ilill • IIIII j .�J ��b /' /9 /n. //..,. / .: t i�✓' at- I y I% < R �H 11/�rlir%�__\`\�1 IIII � IIII f, y 1. /J. •' +/J///j .. �,,' _ _ IV VV n u.r gv s:ER ®oGbM Y•I'SrobG"Ii �q�qu �l1 �G Ea"UMJfa6\:N lb'NOl1CVNi91Nl N019NMIM 9Ydi'J �#IJPI f�b�t9-ZZc t(dtacrtuNtO a twsm ���x rT ��Aa,�m va :: • nm ,-�. °.�V1 w V Q V d ymnoI'DapiON .LjxnoD uaAONVH Axgm NOISNv� NISvfi m'Ha pru NV'Id NOISNv�',�3 NISVH a T U s - NOLMf1usNO:) 2I011 Q3SVTM ION - NOISHU IBI�3 RV /V1.\\ +++ *++++ �11 II i a r� EMT r � w"ii r9lriu (o�i1 fdia.¢0 YNl'IOZIYJ HZZION �, !�, 1110dUIV ' rce�s'+�.�+u n � AillinooWaAONVHm1HN " "' of TdN VCWHF 3�Nl x+tnnn�s�vd xY • IIZLY�O.LS Pm x � s "� a r� I NOyNIWILM �.I,KC10L�iYIdd aerwoau�ao Burd, Tina J From: Burd, Tina J Sent: Thursday, February 6, 2020 4:11 PM To: 'gdick@flyilm.com'; 'rmarconi@tbiilm.com' Subiect: SW8 050547 - Wilmington International Airport EDDB The Wilmington Regional Office of the Division of Energy, Mineral and Land Resources (Stormwater Section) accepted the Stormwater Permit Minor Modification Application for the subiect project on January 29, 2020. The project has been assigned to Garrett Zorda and you will be notified if additional information is needed. Please be advised that the construction of built -upon area may not commence until the Stormwater Permit is issued. Best Regards, Tina Burd Administrative Associate II Wilmington Regional Office Division of Environmental Assistance & Customer Service Phone 910-796-7215 NCDEQ Wilmington Regional Office 127 Cardinal Drive Ext. Wilmington, NC 28405 I Application Completeness Review Checklist (Non-Transtersi - Short version Project Name: KJG f{fisJL: J� C:�w+T sZf�l?T i/ 7r _ { AL) Hfl� i y bate Deiivered to WIRO: t � Z Project County/Location: JE L ] �tA r� �-fie q,,� P 6 Z r RIMS Received./Accepted Date: Rule(s): El2017 Coasta' 1:12008 Coastal r"1995 Coastal BiMS Acknowledged Date: 0Phase Il Universal �1988 Coasta+ Permit Action: New FN ew Permit #z: Major Mod KyMinor):j Renewal ®i=xisting Permit#: 5 Jam, -52547 Permit Type. HD i LD / LD Overall / HD &LD Combo Expriation Date r,;`it AIZ7 General Permit / Offsite / Exempt / Rescission Development Type: Commercial / Residential the, (n."ki kkZPbe_T Subdivided?: Subdivision or Single Lot Permittee Type & Documents Needed: � Rroperty Owner(s) Purchaser ❑LesseE F-11Jiable? ElViabie? E]V'iabie% Deed ElPurchase Agmt 01.ease []Not Subdivided Reed 17Subdivision7 Common Area Deed E]$505 (within 6mo) Cheek#(s): DI)ffsite to SW& ElLot is in Master Permit" Ell Cert. on :pie' ❑HOA MDeveiaoer Viable? Viable% Election Minutes (1 new form or for older forms: 1 original per SCM) Report (Infli or PP) Calculations (signed/sealed) Deed Restrictions, if subdivided' ®Project Narrative "l1SGS Map (or on fife?) Subject to 50Y / N 0Plans (2 Sets) ®PE Certification EElectronic Copies Easements. Recorded (2017 Rules) NOTES: Elva Fee Subject to ORW?: Y / N 'Enter BIMS Acknowledged Daze on this Sheet For New Projects -Enter New Permit # on Supplements & Deed Restiction Temoiaies. If Win 6 months and they are reouesting a mod. STOP. Needs a renewal first. WAILED ENGINEER DATE: NAME: C:4CIPP_F_T Comments: [� C_k A b�� 0.S C3, J Mq bj J bj G:WQ�.,`'Reference'�ibrarvL,Procedures CnecKusts,ComnletenessReviewCnecxnst 20200131 6 t TIM ONS GROUP YOUR VISIGN ACHIEVED THROUGH OURS. Project Name: Circle K— NTI Airport -Wilmington Timmons Project #: 37630.054 Date: 2019-12-04 Stormwater Management Feasibility Background: We have been asked to study whether or not the stormwater for this project can be accommodated by multiple existing pond features located approximately 1,500 feet to the east of the Circle K site. We have been asked to design a proposed drainage ditch, which extends from the Circle K site to the existing pond features. To date, we have not been provided with any record stormwater calculations & record engineering drawing/details of the existing pond features. We understand that there is the intent to develop a large tract of property to the east of the Circle K property. Issues: • The existing upper pond feature has existing 72-inch RCP storm pipes entering and exiting the pond features. Therefore, there is a very large drainage area and flow entering the existing pond from the north. • Without having a copy of the approved stormwater report for the existing pond features, it is unknown whether or not the existing pond features were designed to handle stormwater from the Circle K site. • It is unknown when the existing pond features were constructed. If they were not constructed within the past 15 years, then it is unlikely that they were designed to comply with current NCDEQ stormwater requirements for new development, including the Circle K project. • The existing Circle K property does not drain towards the existing pond features in the existing condition. Therefore, it is unlikely that the existing pond features were designed/sized to handle flow from the Circle K property. • Based on our surveyed topography of the existing upper pond feature, it appears to be very small in proportion to the overall drainage area. Therefore, we understand that it was not designed to meet the requirements of the NCDEQ Stormwater BMP Manual. • The existing upper pond feature appears to have a top of dam elevation of 24. o Although we have not designed a grading plan for the Circle K site to date, we anticipate that the Circle K grades will be in the range of 23 to 26. o Based on the above information, if we were to extend a drainage conveyance from the Circle K site to the existing pond features, then there is the potential during large storms for stormwater to back up through the ditch, and inundate the Circle K parking lot. o The existing topography is not conducive for sending the Circle K stormwater to the existing storm features, because the existing pond features are too high in elevation, as related to the Circle K site. • If Circle K were to attempt to utilize the existing stormwater pond features to meet the NCDEQ stormwater requirements, then we anticipate that NCDEQ would require that all existing pond features be as -built surveyed, and that the pond(s) be significantly expanded/retrofitted to meet current NCDEQ stormwater requirements. We anticipate that NCDEQ would require the existing ponds to be fully re -designed per current standards. A new stormwater study of the entire existing and ultimate drainage area (potentially >100 acres) to the existing pond(s) would be required. • The limited survey data, which we have of the existing upper pond feature does not show any riser in the pond. We have very little survey data of the existing lower pond feature. • Our preliminary ditch design might not be feasible due to the following issues: o The prelim ditch design crosses an existing 15"RCP storm pipe. There is a wetland nearby. It is possible that this drainage feature might be a jurisdictional riparian buffered stream. This would need to be investigated/confirmed. The ditch also crosses over an existing 36"RCP. It is an unusual practice to cross over a storm pipe with a ditch. o The prelim ditch design crosses over an existing paved access drive. As shown, the existing access drive would be severed. This might not be allowed. We do not currently know who/what this access drive serves. It is likely that we would have to pipe our ditch under this access drive. o Our survey shows that the ditch runs through an existing 8" water main and an existing gravity sewer main. Although our limited survey information does not show it, it is likely that these are public water and sewer mains, with public water and sewer easements. The municipality would likely require the ditch to be piped through the water and sewer easement at a 90 degree angle. We may need subsurface utility locate information on the existing utilities at the crossing in order to design our storm pipe to avoid pipe conflicts. o The prelim ditch is designed at 1/2 percent slope. This is not recommended, because at this flat slope, in our experience, the ditch will likely accumulate several feet depth of sediment over the course of 10 years, potentially causing stormwater to backup on Circle K property. Routine excavation of the sediment from the ditch would be needed. o The prelim ditch design would cause stormwater from the existing pond feature to be circumvented during large storms, due to the topography_ The ditch crosses a low area of elevation 19. The existing pond feature has a top of dam elevation of 24. ■ In order to avoid circumventing the pond feature, a 1,400 foot long berm adjacent to the ditch would need to be constructed at elevation 24 or higher. • This 1,400 foot long ditch/berm would effectively become a part of the existing pond. The ditch would elongate the pond by 1,400 feet. During large storms, this elongated ditch/berm would cause a significant area of inundation/flooding on the future development area between the Circle K property and the existing pond features unless a large volume of dirt were imported from offsite in order to raise the elevation of the future development. o The prelim ditch design would cause a large drainage area to be re -directed away from its existing drainage pattern. This is not recommended, and generally not allowed from a legal/liability standpoint, as it could have adverse drainage & flooding impacts to downstream properties. o The cost to grade the 1,400 ft long drainage ditch and earth berm would be significant. o An offsite drainage easement would be needed. o This drainage ditch could reduce the development potential of adjacent properties to the east of Circle K. Conclusions: For the above reasons, we do not believe it is feasilble for the Circle K project to construct a 1,400 foot long drainage ditch to utilize the existing pond features located 1,500 feet to the east for Circle K stormwater management. Recommendations: In order to meet the current NCDEQ stormwater requirements for the Circle K project, we recommend exploring the following stormwater alternatives: • In the existing condition, the majority of the Circle K property drains to the south, through an existing 24" RCP culvert under N 23rd Street. In order to maintain the existing drainage pattern, we recommend that a stormwater SCM be designed to the south of the Circle K property, just southeast of the proposed "Private Street" driveway intersection of N 23rd Street, near the existing 24"RCP culvert. Options for this stormwater SCM could include a proposed wet detention pond, bioretention, sand filter, stormwater wetland, ConTech Stormfilter, and/or underground detention. • We recommend that the future overall development around Circle K be master plan designed, and include regional stormwater facilities for the master planned overall project. We anticipate that this would include multiple stormwater SCMs, based on the existing topography. The topography indicates the need for a new stormwater SCM located approximately 500 feet to the southeast of the Circle K property. This additional SCM should not be needed for the Circle K project, but is anticipated to serve the future development to the east of Circle K. • Given the above issues, we do not anticipate that the existing pond features should be used to handle the comprehensive stormwater needs of the overall future master planned area. It is possible that the existing pond features could be utilized to handle a portion of the future master planned area, far to the east of the Circle K project. However, given the issues above, it might be more practical to construct new stormwater SCMs than to analyze and retrofit/expand the existing pond features. Q tk- Ville PH 4t- USGS MAP