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HomeMy WebLinkAboutSW7080704_CURRENT PERMIT_20091203STORMWATER DIVISION CODING SHEET POST -CONSTRUCTION PERMITS PERMIT NO. SW -70e2 /0// DOC TYPE CURRENT PERMIT E] APPROVEDPLANS El HISTORICAL FILE El COMPLIANCE EVALUATION INSPECTION DOC DATE YYYYMMDD NCDENR North Carolina Department of Environment and Beverly Eaves Perdue Governor County of Dare Attn: Mr. Robert Outten PO Box 1000 Manteo, NC 27954 Dear Mr. Outten: Division of Water Quality Coleen H. Sullins Director December 3, 2009 Natural Resources Dee Freeman Secretary Subject: Stormwater Permit No. SW7080704 Bowsertown Landing Residential High Density Stormwater Project Dare County The Washington Regional Office received your complete Stormwater Management Permit application on October 5, 2009. Staff review of the plans and specifications has determined that the project, as proposed, will comply with the Stormwater Regulations set forth in Title 15A NCAC 2H.1000. We are forwarding Permit No. SW7080704 dated December 3, 2009 for the subject project. This permit shall be effective from the date of issuance until December 3, 2019, and shall be subject to the conditions and limitations as specified therein. Please pay special attention to the Operation and Maintenance requirements in this permit and in the submitted application. Failure to establish an adequate system for operation and maintenance of the stormwater management system will result in future compliance problems. If any parts, requirements, or limitations contained in this permit - are unacceptable, you have the right to request an adjudicatory hearing upon written request within thirty (30) days following receipt of this permit. This request must be in the form of a written petition, conforming to Chapter 150B of the North Carolina General Statutes, and filed with the Office of Administrative Hearings, P.O. Drawer 27447 Raleigh, NC 27611-7447. Unless such demands are made this permit shall be iinal and binding. I North Carolina Division of Water Quality Internet: %Nr%vWncwaterqualitv.or- 943 Washington Square Mall Phone: 46-6481 Washington, NC 27889 FAX 252-946-9215 An Equal Opportunity/Affirmative Action Employer — 50% Recycled/10% Post Consumer Paper Une NorthCarolina ;Vatu.nally Page 2 of 9 County of Dare December 3, 2009 Page Two If you have any questions, or need additional information concerning this matter, please contact either Bill Moore, or me at (252) 946-6481. i incerely, H1 +gz� Regional Supervisor Surface Water Protection Section cc: Michael W. Robinson, P.E., P.L.S. Dare County Planning/Inspections .ZWashington Regional Office Central Files Page 3 of 9 STATE OF NORTH CAROLINA DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES DIVISION OF WATER QUALITY 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 County of Dare Bowsertown Landing Residential Development Dare County FOR THE construction, operation and maintenance of a stormwater system consisting of infiltration basins, swales, and subsurface trenches, in compliance with the provisions of 15A NCAC 2H .1000 (hereafter referred to as the "stormwater rules') and the approved stormwater management plans and specifications and other supporting data as attached and on file with and approved by the Division of Water Quality and considered a part of this permit. This permit shall be effective from the date of issuance until December 3, 2019 and shall be subject to the following specified conditions and limitations: 1. DESIGN STANDARDS This permit is effective only with respect to the nature and volume of stormwater described in the application and other supporting data. This stormwater system has been approved for the management of stormwater runoff as described in Section 1.6 on page 4 of this permit. The stormwater controls have been designed to handle the runoff from 47,006 square feet of impervious area. 3. All stormwater collection and treatment systems must be located in either dedicated common areas or recorded easements. The final plats for the project will be recorded showing all such required easements, in accordance with the approved plans and permit. 4. The tract will be limited to the amount of built -upon area indicated on page 4 of this permit, and per approved plans. Page 4 of 9 P A The runoff from all built -upon area within the permitted drainage areas of this project must be directed into the permitted stormwater control system. The following design criteria have been provided for the infiltration basins and must be maintained at design condition: a. Total Site Area: 5.60 acres b. Total Impervious Surfaces: 1.08 acres C. Design Storm: 1.5 - inch d. Basin Depth: 1.0 ft e. TSS removal efficiency: 85% f. Total Storage Volumes for Infiltration Basins: 7640 cf g. Total Storage Volumes for Infiltration Swales: 2928 ef h. Total Storage Volumes for Subsurface Trenches: 300 cf i. Storage Elevation, FMSL: 4.0 ft j. Receiving Stream/River Basin: UT-Croatan Sound k. Classification of Water Body: SA 11. SCHEDULE OF COMPLIANCE 1 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. 2. During construction, erosion shall be kept to a minimum and any eroded areas of the system will be repaired immediately. 3. The permittee shall at all times provide the operation and maintenance necessary to assure the permitted stormwater system functions at optimum efficiency. The approved Operation and Maintenance Plans 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 bypass structure, filter media, flow spreader, catch basins, piping and vegetated filter. Page 5 of 9 9. A clear access path to the bypass structure must be available at all times. 4. Records of maintenance activities must be kept and made available upon request to authorized personnel of DWQ. The records will indicate the date, activity, name of person performing the work and what actions were taken. 5. The facilities shall be constructed as shown on the approved plans. This permit shall become voidable unless the facilities are constructed in accordance with the conditions of this permit, the approved plans and specifications, and other supporting data. 6. 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. 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 stormwater facilities shall be maintained via appropriate easements at all times. 9. The permittee shall submit to the Director and shall have received approval for revised plans, specifications, and calculations prior to construction, for any modification to the approved plans, including, but not limited to, those listed below: a. Any revision to any item shown on the approved plans, including the stormwater management measures, built -upon area, details, etc. b. Project name change. C. Transfer of ownership. d. Redesign or addition to the approved amount of built -upon area or to the drainage area. e. Further subdivision, acquisition, lease or sale of all or part of the project area. The project area is defined as all property owned by the permittee, for which Sedimentation and Erosion Control Plan approval or a CAMA Major permit was sought. f. Filling in, altering, or piping of any vegetative conveyance shown on the approved plan. 10. The permittee shall submit final site layout and grading plans for any permitted future areas shown on the approved plans, prior to construction. 11. A copy of the approved plans and specifications shall be maintained on file by the Permittee at all times. Page 6 of 9 12. 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. 13. This permit shall be effective from the date of issuance until December 3, 2019. Application for permit renewal shall be submitted 180 days prior to the expiration date of this permit and must be accompanied by the processing fee. Ill. GENERAL CONDITIONS This permit is not transferable except after notice to and approval by the Director. In the event of a change of ownership, or a name change, the permittee must submit a formal permit transfer request to the Division of Water Quality, accompanied by a completed name/ownership change form, documentation from the parties involved, and other supporting materials as may be appropriate. The approval of this request will be considered on its merits and may or may not be approved. The permittee is responsible for compliance with all permit conditions until such time as the Division approves the transfer request. Failure to abide by the conditions and limitations contained in this permit may sub)ect the Permittee to enforcement action by the Division of Water Quality, in accordance with North Carolina General Statute 143-215.6A to 143-215.6C. 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. 4. In the event that the facilities fail to perform satisfactorily, including the creation of nuisance conditions, 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. The permittee grants DENR 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 may be modified, revoked and reissued or terminated for cause. The filing of a request for a permit modification, revocation and reissuance or termination does not stay any permit condition. 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. Page 7 of 9 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 for the life of the project. 9. The permittee shall notify the Division of any name, ownership or mailing address changes within 30 days. Permit issued this the 3 rd day of December, 2009. NORTH CAROLINA ENVIRONMENTAL MANAGEMENT COMMISSION 1: for Division of Water Quality By Authority of the Environmental Management Commission Permit Number SW7080704 Page 8 of 9 Stormwater Permit No. SW7080704 Bowsertown Landing Residential Development Infiltration Systems Dare County Designer's Certification 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. Note: The checklist on the following page must be included with this Certification. Any changes or deviations from the approved plans and specifications must be explained in detail, and may require a permit modification. The certification forms should be submitted to the Division of Water Quality at the appropriate Regional office. SEAL Signature Registration Number Date Page 9 of 9 Comf lete this checklist for each system and include with Certi cation: 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 roof drains are located such that the runoff is directed into the system. 5. The bypass structure elevations are per the approved plan. 6. The bypass 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. All required design depths are provided. 13. All required parts of the system are provided. 14. The required system dimensions are provided per the approved plans. zn,A.. 7111los DWQ USE ONLY,' Date Received Fee Paid Permit Number !L?-5-- ()C� 5—o S— E� 7aq o zi� State of North Carolina Department of Environment and Natural Resources Division of Water Quality STORMWATER MANAGEMENT PERMIT APPLICATION FORM ZF-, Thisforin niay be photocopiedfor use as an ofiginal OCT 0 5 2009 . 1. GENERAL INFORMATION 1. Applicants name (specify the name of the corporation, individual, etc. who owns the project): Dare County Xsyoe. PO 15-Y ,> 2. Print Owner/Signing Official's name and title (person legally responsible for facility and compliance): Rnhprf niiffpn AqQiqfnnt Cniinfv Mannapr Cntinfv Affnrnpv e-_-X"fk R. /)11' 3. Mailing Address for person listed in item 2 above: City: Manteo State:NC Zip:27954 Phone: (252 475-5800 Fax: (252 473-1817 Email: outten@co.dare.nc.us 4. Project Name (subdivision, facility, or establishment name -should be consistent with project name on plans, specifications, letters, operation and maintenance agreements, etc.): Bowsertown Landing Residential Development 5. Location of Project (street address): 170 South California Street City: Manteo County:Dare Zip:27954 6. Directions to project (from nearest major intersection): Route 64/264 to Roanoke Island, South on Bowsertown road, left onto S. California Lane. The Rroject is on the right just past the Coun!y boat ramp 7. Latitude:35'53'55"N Long, . tude:075' 41' 02" W of project 8. Contact person who can answer questions about the project: Name: Michael W. Robinson, P.E. Telephone Number: (252 ) 255-8026 Email: mrobinson@obxengineering.com 11. PERMIT INFORMATION: Fonn SWU-101 Version 03.27.08 Page I of 4 1. Specify whether project is (check one): ENew E]Renewal E]Modification 2. If this application is being submitted as the result of a renewal or modification to an existing permit, list the existing permit number and its issue date (if known) 3. Specify the type of project (check one): FLow Density EHigh Density E]Redevelop []GeneralPermit E]UniversaISMP 00ther 4. 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): FICAMA Major ZSedimentation/ Erosion Control E]404/401 Permit []NPDES Stormwater III. PROJECT INFORMATION 1. In the space provided below, summarize how stormwater will be treated. Also attach a detailed narrative (one to two pages) describing stormwater management for the project. All runoff from impervious surfaces will be retained and infiltrated in an interconnected series of shallow basins, shallow swales and a perforated pipe roof runoff infiltration system. 2. Stormwater runoff from this project drains to the Pasquotank River basin. 3. Total Property Area: 5.60 acres 4. Total Wetlands Area: 2.74 acres 5. 100' Wide Strip of Wetland Area: 1.91 acres (not applicable if no wetlands exist on site) 6. Total Project Area**: 5.60 acres 7. Project Built Upon Area:1.079 ac 19.27% % 8. How many drainage areas does the project have? 2 j,oe) / C.6 ;z &, -3 91r, 9. Complete the following information for each drainage area. If there are more than two drainage areas in the project, attach an additional sheet with the information for each area provided in the same format as below. For high density projects, complete the table with one drainage area for each engineered stormwater device. 'Basin Information rea Dramiage A A" Drain 54e Area 2 Receiving Stream Name Croatan Sound Croatan Sound Stream Class & Index No. SA 30-20 SA 30-20 Total Drainage Area (so 47,006 196,926 On -site Drainage Area (so 0 0 Off -site Drainage Area (so 0 0 Existing Impervious* Area (so 0 0 Proposed Impervious*Area (so 47,006 0 % Impervious* Area (total) 100 0 :Impervious Surface Area Drainage Area Drainage 'Area 2 On -site Buildings (so 20,223 0 On -site Streets (so 26,783 0 On -site Parking (so included in streets 0 On -site Sidewalks (so 0 0 ,Other on -site (so 0 0 P��0 0 0 Total (so: 47,006 0 linpervious area is defined as the built upon area including, but not linfl�ted to, buildings, roads, parking areas, sidewalks, gravel areas, etc. Form SWU-101 Version 03.27.08 Page 2 of 4 **Total project area shall be calculated based on the current policy regarding inclusion of wetlands in the built upon area percentage calculation. This is the area used to calculate percent project built upon area (BUA). 10. How was the off -site impervious area listed above IV. DEED RESTRICTIONS AND PROTECTIVE COVENANTS One of the following deed restrictions and protective covenants are required to be recorded for all subdivisions, outparcels and future development prior to the sale of any lot. If lot sizes vary significantly, a table listing each lot number, size and the allowable built -upon area for each lot must be provided as an attachment. Forms can be downloaded from http://h2o.enr.state.nc.us/sulbml2 forms.htm - deed restrictions. Form DRPC-1 High Density Commercial Subdivisions Form DRPC-2 High Density Developments with Outparcels Form DRPC-3 High Density Residential Subdivisions Form DRPC-4 Low Density Commercial Subdivisions Form DRPC-5 Low Density Residential Subdivisions Form DRPC-6 Low Density Residential Subdivisions with Curb Outlets By your signature below, you certify that the recorded deed restrictions and protective covenants for this project shall include all the applicable items required in the above form, 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 State, and that they will be recorded prior to the sale of any lot. V. SUPPLEMENT FORMS The applicable state stormwater management permit supplement form(s) listed below must be submitted for each BMP specified for this project. Contact the Stormwater and General Pern-dts Unit at (919) 733-5083 for the status and availability of these forms. Forms can be downloaded from httl2://h2o.enr.state.nc.us/su/bmp forms.htm. Form SW401 -Low Density Form SW401-Curb Outlet System Form SW401-Off-Site System Form SW401-Wet Detention Basin Form SW401-Infiltration Basin Form SW401-Infiltration Trench Form SW401-Bioretention Cell Form SW401-Level Spreader Form SW401-Wetland Form SW401-Grassed Swale Form SW401-Sand Filter Form SW401-Permeable Pavement Low Density Supplement Curb Outlet System Supplement Off -Site System Supplement Wet Detention Basin Supplement Infiltration Basin Supplement Underground Infiltration Trench Supplement Bioretention Cell Supplement Level Spreader/Filter Strip/Restored Riparian Buffer Supplement Constructed Wetland Supplement Grassed Swale Supplement Sand Filter Supplement Permeable Pavement Supplement Fonn SWU-101 Version 03.27.08 Page 3 of 4 V1. SUBMITTAL REQUIREMENTS Only complete application packages will be accepted and reviewed by the Division of Water Quality (DWQ). A complete package includes all of the items listed below. The complete application package should be submitted to the appropriate DWQ Office. (Appropriate office maybe found by locating project on the interactive online map at http://h2o.enr.state.nc.us/su/msi maps.htm) 1 1. Please indicate that you have provided the following required information by initialing in the space provided next to each item. • Original and one copy of the Stormwater Management Permit Application Form • Original and one copy of the Deed Restrictions & Protective Covenants Form (if required as per Part IV above) • Original of the applicable Supplement Form(s) and O&M agreement(s) for each BMP • Permit application processing fee of $505 (Express: $4,000 for HD, $2,000 for LD) payable to NCDENR • Calculations & detailed narrative description of stormwater treatment/ management • Copy of any applicable soils report • Two copies of plans and specifications (sealed, signed & dated), including: - Development/ Project name - Engineer and firm -Legend - North arrow - Scale Revision number & date Initials M '�?_ M lk'_2 ,Y) "'. - Mean high water fine - Dimensioned property/project boundary - Location map with named streets or NCSR numbers - Original contours, proposed contours, spot elevations, finished floor elevations - Details of roads, drainage features, collection systems, and stormwater control measures - Wetlands delineated, or a note on plans that none exist - Existing drainage (including off -site), drainage easements, pipe sizes, runoff calculations - Drainage areas delineated - Vegetated buffers (where required) V11. AGENT AUTHORIZATION If you wish to designate authority to another individual or firm so that they may provide information on your behalf, please complete this section. (ex. designing engineer or firm) Designated agent (individual or firm): Michael W. Robinson P.E. Mailing Address: P.O. Box 2852 City: Kill Devil Hills State: NC Zip: 27948 Phone: (252 ) 255-8026 Fax: Email:- mrobinson@obxengineering.com VIII. APPLICANT'S CERTIFICATION 1, (print or type naine of person listed in General Information, itern 2) Robert Outten, Countit Attorney I certify that the information included on this permit application form is, to the best of my knowledge, correct and that the project wil nstructed in conformance with the approved plans, that the required deed restrictions "I and protective c9lenants \Vill recorded, and that the proposed project complies with the requirements of 15A NCAC2H.100(Y. , A., r I Form SWU-101 Version 03.27.08 Page 4 of 4 Date: O� W A Tf,� AOWQ67- A MD1. 217A STORMWATER MANAGEMENT PERMIT APPLICATION FORM HCDENR 401 CERTIFICATION APPLICATION FORM INFILTRATION BASIN SUPPLEMENT This form must be filled out, printed and submitted. The Required Items Checklist (Part III) must be printed, filled out and submitted along with all of the required information. 11. PROJECT INFORMATIOW': "'4-" " — W, Project Name Bowsertown Landing Residential Development Contact Person Michael W. Robinson, RE Phone Number 252-255-8026 Date 1011009 Drainage Area Number 1 -impervious surfaces FIL', DESIGN INFORMATION,!'-� Site Characteristics Drainage area 47,006.00 ft2 Impervious area 47,006.00 112 Percent impervious 1.00 % OCT 0 5 2009 Design rainfall depth 1.50 in Peak Flow Calculations 1 -yr, 24-hr rainfall depth 3.42 in lt!.� 1-yr, 24-hr intensity 0.14 in/hr Pre -development 1 -yr, 24-hr discharge 0.00 It 3 /sec Post -development 1 -yr, 24-hr discharge 3.76 113 /sec: Pre/Post 1-yr, 24-hr peak flow control 3.76 ft/sec Storage Volume: Non -SA Waters Minimum design volume required Design volume provided Storage Volume: SA Waters 1.5" runoff volume Pre -development I -yr, 24-hr runoff volume Post -development 1 -yr, 24-hr runoff volume Minimum required volume Volume provided Solis Report Summary Soil type Infiltration rate SHWT elevation Basin Design Parameters Drawcown time Basin side slopes Basin bottom elevation Storage elevation Storage Surface Area Top elevation Basin Bottom Dimensions Basin length Basin width Bottom Surface Area 5414.00 it' 0.00 it, 5,414.00 it' 5414.00 it' it' L�Z OK 10,868.00 Loamy Sand 7._ infhr ::77�tov' fm S I 1.00 days OK 4.00 :1 OK fmsl 11_� OK 2.55 fmsl 9,610.00 it, 4.00 fmsl varies it varies it 5,060.00 it' Form SW401 -infiltration Basin-Rev.4 Parts 1. & 11, Design Summary, Page 1 of 2 Additional Information Maximum runoff to each inlet to the basin? ac-in Permit No. Length of vegetative filter for overflow n/a ft OK (to be pmvided by DWO) Distance to structure n/a OK Distance from surface waters 90.00 ft OK Distance from water supply well(s) n/a It OK Separation from impervious soil layer n/a it OK Naturally occuring soil above shwt 1.50 It OK Bottom covered with 4-in of clean sand? y .(Y or N) OK Proposed drainage easement provided? n/a (Y or N) OK Capures all runoff at ultimate build -out? y (Y or N) OK Bypass provided for larger storms? y (Y or N) OK Pretreatment device provided y Interconnected swales and gutter collection system Forrn SW401-Infiltration Basin-Rev.4 Parts 1. & H. Design Summary, Page 2 of 2 AkT;_5;WA TA STORMWATER MANAGEMENT PERMIT APPLICATION FORM HCDENR 401 CERTIFICATION APPLICATION FORM INFILTRATION BASIN SUPPLEMENT This form must be filled out, printed and submitted. The Required Items Checklist (Part /11) must be printed, filled out and submitted along with all of the required information. Contact Person Phone Number Date Drainage Area Number Michael W. Robinson, P.E. 252-255-8026 1011/2009 2-Open space and qreen areas ')f WATfi, 650&_&_Qk 20 - - C. 0 Nii� , j G DESIGN INFORMATION Site Characteristics Drainage area 196,926.00 ft2 Impervious area 0.00 It 2 Percent impervious 0.00 % Design rainfall depth 1.50 in Peak Flow Calculations 1 -yr, 24-hr rainfall depth 3.42 in 1 -yr, 24-hr intensity 0.14 in/hr Pre -development 1 -yr, 24-hr discharge 0.00 ft/sec Post -development 1 -yr, 24-hr discharge 0.00 ft3/sec Pre/Post 1 -yr, 24-hr peak flow control 0.00 ft/sec Storage Volume: Non -SA Waters Minimum design volume required ft3 Design volume provided ft3 Storage Volume: SA Waters 15' runoff volume 0.00 ft3 Pre -development 1-yr, 24-hr runoff volume 0.00 ft3 Post -development 1 -yr, 24-hr runoff volume 0.00 W Minimum required volume 0.00 it, Volume provided 0.00 ft 3 OK Solis Report Summary Soil type Loamy Sand Infiltration rate 7.50 in/hr SHVVT elevation 1.00 fmSI Basin Design Parameters Drawdown time 1.00 days OK Basin side slopes 4.00 :1 OK Basin bottom elevation 3.00 knsl OK Storage elevation 2.55 fmsl Storage Surface Area 9,610.00 it' Top elevation 4.00 fmsl Basin Bottom Dimensions Basin length van r es it Basin width varies it Bottom Surface Area 5,060.00 it' Form SW401 -infiltration Basin-Rev.4 Parts 1. & 11. Design Summary, Page I of 2 Additional Information Ma)dmum runoff to each inlet to the basin? ac-in Permit No. Length of vegetative filter for overflow n1a ft OK (to be provided by DWQ) Distance to structure n/a ft OK Distance from surface waters 90.00 ft OK Distance from water supply well(s) n/a It OK Separation from impervious soil layer n/a It OK Naturally oocuring soil above shwt 1.50 It OK Bottom covered with 4-in of clean sand? y (Y or N) OK Proposed drainage easement provided? n/a (Y or N) OK Capures all runoff at ultimate build -out? y (Y or N) OK Bypass provided for larger storms? (Y or N) OK Pretreatment device provided y Interconnected swales and gutter collection system Fornn SW401 -infiltration Basin-Rev.4 Parts 1. & 11. Design Summary, Page 2 of 2 OCT 0 5 2009 Permit Number: (to be provided by D WQ) Drainage Area Number: Infiltration Basin Operation and Maintenance Agreement I will keep a maintenance record on this BMP. This maintenance record will 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 removal efficiency of the BMP. Important maintenance procedures: — The drainage area will be carefully managed to reduce the sediment load to the infiltration basin. — Immediately after the infiltration basin is established, the vegetation will be watered twice weekly if needed until the plants become established (commonly six weeks). — No portion of the infiltration basin will be fertilized after the initial fertilization that is required to establish the vegetation. — The vegetation in and around the basin will be maintained at a height of approximately six inches. After the infiltration basin is established, it will be inspected once a quarter and within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a Coastal County). 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: I will remediate the problem: The entire BMP --How Trash/debris is present. Remove the trash/debris. The perimeter of the Areas of bare soil and/or Regrade the soil if necessary to infiltration basin erosive gullies have formed. remove the gully, and then plant a ground cover and water until it is established. Provide time and a one-time fertilizer application. The inlet device: pipe or The pipe is clogged (if Unclog the pipe. Dispose of the Swale applicable). sediment off -site. The pipe is cracked or Replace the pipe. otherwise damaged (if applicable). Erosion is occurring in the Regrade the Swale if necessary to Swale (if applicable). smooth it over and provide erosion control devices such as reinforced turf matting or riprap to avoid future problems with erosion. Form SW40 I -Infiltration Basin O&M-Rev.3 Page I of 3 BMP element., Potential problem: How I wil I remediate the problem: The forebay Sediment has accumulated Search for the source of the and reduced the depth to 75% sediment and remedy the problem if of the original design depth. possible. Remove the sediment and dispose of it in a location where it will not cause impacts to streams or the BMP. Erosion has occurred or Provide additional erosion riprap is displaced. protection such as reinforced turf matting or riprap, if needed to prevent future erosion 2roblems. Weeds are present. Remove the weeds, preferably by hand. If pesticides are used, wipe them on the plants rather than spraying. The main treatment area A visible layer of sediment Search for the source of the has accumulated. sediment and remedy the problem if possible. Remove the sediment and dispose of it in a location where it will not cause impacts to streams or the BMP. Replace any media that was removed in the process. Revegetate disturbed areas irrimediately. Water is standing more than Replace the top few inches of filter 5 days after a storm event. media and see if this corrects the standing water problem. If so, revegetate immediately. If not, consult an appropriate professional for a more extensive repair. Weeds and noxious plants are Remove the plants by hand or by growing in the main wiping them with pesticide (do not treatment area. spray). The embankment Shrubs or trees have started Remove shrubs or trees to grow on the embankment. immediately. An annual inspection by an Make all needed repairs. appropriate professional shows that the embankment needs repair. 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 NC Division of Water damage have occurred at the Quality 401 Oversight Unit at 919- outlet. 733-1786. Form SW401 -Infiltration Basin O&M-Rev.3 Page 2 of 3 I f Permit Number: (to be provided by DWQ) I acknowledge and agree by my signature below that I am responsible for the performance of the maintenance procedures listed above. I agree to notify DWQ of any problems with the system or prior to any changes to the system or responsible party. Project name:Bowsertown Landing Residential Development BMP drainage area numher: I - Entire Site Print name:County of Dare c/o Bobby Outten Title:Assistant County Manager and Attomey Date: cz_> C/1 0) Note: The legally responsible party should not be a homeowners association unless more than 50% of the lots have been sold and a resident of the subdivision has been named the president. 1, \_&)IL E Wi /./I a , ms , a Notary Public for the State of NOH-A QOLrphoo, County of - -ZOf--e— , do hereby certify that -Roberi­ j- . D(A-tttt-) personally appeared before me this day of 0394 �ppq and acknowledge the due execution of the forgoing infiltration basin maintenance requirements. Witness my hand and official seal, % "tS1511188#01 ),0 T A B 00 JCP Co., SEAL My commission expires I I - -� 7 - /:!> Form SW401 -Infiltration Basin O&M-Rev.3 Page 3 of 3