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HomeMy WebLinkAboutSW7080503_CURRENT PERMIT_20080529STORMWATER DIVISION CODING SHEET POST -CONSTRUCTION PERMITS PERMIT NO. Sw DOC TYPE CURRENT PERMIT El APPROVED PLANS El HISTORICAL FILE El COMPLIANCE EVALUATION INSPECTION DOC DATE YYYYMMDD wa:Ko Michael F. Easley, Governor Williarn G. Ross Jr., Secretary North Carolina Department of Environment and Natural Resources Coleen H. Sullins, Director Division of Water Quality May 29, 2008 Pasquotank County Aftn.: Randy Keaton P.O. BOX 56 Elizabeth City, NC 27909 Subject: Stormwater Review SW7080503 Reverse Osmosis Water Treatment —Phase 11 High Density Permit Pasquotank County Dear Mr. Keaton: The Washington Regional Office received a complete Stormwater Management Permit Application for the subject project on May 05, 2007. 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. SW70080503 dated May 29, 2008 for the construction of the subject project. This permit shall be effective from the date of issuance until May 29,2018 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. 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, 6714 Mail Service Center, Raleigh, NC 27699-6714. Unless such demands arb made this permit shall be final and binding. If you have any questions, or need additional information concerning this matter, please contact Ernest Odei- Larbi, or me at (252) 946-6481. cerl, oJ Regional Supervisor� Surface Water Protection Section AH/eol: J:\WPDATA\WQS\ State SW-EOL\Permits — Wet pond\2008 cc: David T. UpChurch- Hobbs, Upchurch & Associates, P.A (300 S.W Broad Street, Southern Pines, NC 28387) Ppquotank County Planning/inspection t.)4ashington Regional Office Central File North Carolina Division of Water Quality Internet: �vwncwaterqualirv.org 943 Washington Square Mali Phone (252) 946-6481 Washington, NC 27889 Fax (252) 946-9215 One NorthCarolina Natimally An Equal Opportunity/Affirmative Action Employer — 50% Recycled/l 0% Post Consumer Paper State Stormwater Management Systems Permit No. SW708050i 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 Pasquotank County FOR THE construction, operation and maintenance of a wet detention pond 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 May 29, 2018 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. 2. This stormwater system has been approved for the management of stormwater runoff as described in Section 1.6 on page 3 of this permit. The stormwater control has been designed to handle the runoff from 80,000 square feet of impervious area. 3. The tract will be limited to the amount of built -upon area indicated on page 3 of this permit, and per approved plans. 4. 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. 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. kA State Stormwater Management Systems Permit No. SW7080503 6. The following design criteria have been provided in the wet detention pond and must be maintained at design condition: Total Impervious Surfaces, ft: 80,000 (designed for 85,560) Design Storm, inches: 1.5 Receiving §tream: Little River Classification of Water Body: C; SW Total Site Area: 4.14 ac Drainage area: 4.14 ac Total Impervious allowed on site: 80,000 sf TSS removal efficiency: 90% Wet Pond Ave. Depth: 3.04 ft Required Storage Volume: 47.083 cf Provided Storage Volume: 47,083 cf Required Surface Area: 5,484.86 sf Provided Surface Area: 15,463 sf Permanent Pool Volume: 47,083 cf Permitted Forebay Volume: 10,414 cf Controlling Orifice: 2 inch Permanent Pool Elevation, FMSL Temporary Storage Elevation 6.0 ft. MSL 3 State Stormwater Management Systems, Permit No. SW7080503 11. 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. 2. During construction, erosion shall be kept to a minimum and any eroded areas of the system will be repaired immediately. 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 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. 9. Access to the outlet structure must be available at all times. 4. Records of maintenance activities must be kept and made available upon request to authorized personnel of DWO. The records will indicate the date, activity, name of person performing the work and what actions were taken. 5. Decorative spray fountains will be allowed in the stormwater treatment system, subject to the following criteria: a. The fountain must draw its water from less than 2' below the permanent pool surface. b. Separated units, where the nozzle, pump and intake are connected by tubing, may be used only if they draw water from the surface in the deepest part of the pond. c. The falling water from the fountain must be centered in the pond, away from the shoreline. d. The maximum horsepower for a fountain in pond is 1/6 HP horsepower. 6. 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. 7. 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. 8. 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. 9. Access to the stormwater facilities shall be maintained via appropriate easements at all times. % 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: State Stormwater Management Systems Permit No. SVV7080503 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. 11. The permittee shall submit final site layout and grading plans for any permitted future areas shown on the approved plans, prior to construction. 12. A copy of the approved plans and specifications shall be maintained on file by the Pernnittee at all times. 13. 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. Ill. GENERAL CONDITIONS 1 . 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 pates 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. 2. Failure to abide by the conditions and limitations contained in this permit may subject 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. 3. 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. 5. 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. 8. Approved plans and specifications for this project are incorporated by reference and are enforceable parts of the permit. 9. The permittee shall notify the Division any name, ownership or mailing address changes within 30 days. State Stormwater Management Systems, I Permit No. SW7080503 10. This permit shall be effective from the date of issuance until. Application for permit renewal shall be submifted 180 days prior to the expiration date of this permit and must be accompanied by the processing fee. Permit issued this the 29th day of May 2008, NORTH CAROLINA ENVIRONMENTAL MANAGEMENT COMMISSION fflrColeen H. Sullins, Director Division of Water Quality By Authority of the Environmental Management Commission Permit Number SW7080503 State Stormwater Management Systems Permit No. SW7080503 Reverse Osmosis Water Treatment —Phase 11 Pasquotank County Designer's Certification 1. , 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: SEAL Signature Registration Number Date State Stormwater Management Systems Permit No. SW7080503 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 roof drains are located such that the runoff 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. 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 devices are correctly sized per the approved plans. 13. All required design depths are provided. 14. All required parts of the system are provided, such as a vegetated shelf, and a forebay. 15, The required system dimensions are provided per the approved plans. cc: NCDENR-DWQ Regional Office Pasquotank County Building Inspections ==-- -- , - -- DWQ USE ONLY Date Received Fee Paid Permit Number MAY 2 b Z U U 0 V05 4VO90509 UlPf"'AIVAR0 44 Department of Environment and Natural Resources State of North Carolina Division of Water Quality STORMWATER MANAGEMENT PERMIT APPLICATION FORM Thisforin inay be photocopiedfor use as an original 1. GENERAL INFORMATION I . Applicants name (specify the name of the corporation, individual, etc. who owns the project): Pasquotank Count3� 2. PrintOwner/Signing Official's name and title (person legally responsible for facility and compliance): Randy Keaton -County Manager 3. Mailing Address for person listed in item 2 above: P.O. Box 56 City:Elizabeth Ci!�� - State:NC Zip:27909 Phone: (252 335-2240 Fax: (252 335-0866 Email: 4. Project Name (subdivision, facility, or establishment name - should be consistent with project name on plans, specifications, letters, operation and maintenance agreements, etc.): Pasquotank County Reverse Osmosis Water Treatment Plans -Phase 11 5. Location of Project (street address): 1,000 LF West along SRI 144 from intersection of SRI 140, SR-1144, and SR1303 City:Elizabeth City County:Pasquotank 6. Directions to project (from nearest major intersection): 1,000 LF West along SRI 144 from intersection of SRI 140, SRI 144, and SR1303 7. LatitUde:36 Degrees 16' 15" Longitude:76 Degrees 22' 08" of project 8. Contact person who can answer questions about the project: Nanie:lanies D. Freeman Telephone Number: (910 ) 692-5616 l�-'rii�iil:lFreeiiiaii@liobbsupcliurch.com Il. PERMIT INFORMATION: 1 . Specify whether project is (check one): ZNew DRenewal E]Modification Fonn SWU-101 Version 8.07 Page I ol'4 2. If this application is being submitted as the result of a renewal or modification to all existing permit, list the existing permit number and its issue (late (if known) 3. Specify the type of project (check one): F_]Low Density ZHigh Density E]Redevelop E]General Permit DUniversal SMP DOther 4. Additional Project Requirements (check applicable blanks): F_1CAMA Major NSedimentation/ Erosion Control []404/401 Permit E:1NPDES Stormwater Information on required state permits can be obtained by contacting the Customer Service Center at 1-877-623-6748. Ill. 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. Stormwater for this project will be treated via a wet pond designed in accordance with the current DW standards. All runoff from the developed area will be routed in to the pond's forebay. The pond is designed for the ultimate build out of impervious surfaces. 2. Stormwater runoff from this project drains to the Pasquotank River basin. 3. Total Site Area: 4.14 acres 4. Total Wetlands Area: 0 acres 5. 100' Wide Strip of Wetland Area: N/A acres (not applicable if 110 Wetlands exist on site) 6. Total Project Area**:4.14 acres 7. Project Built Upon Area:48 % 8. How many drainage areas does the project have?l 9. Complete the following information for each drainage area. If there are more than two drainage areas in the project, attach all additional sheet with the information for each area provided in the same format as below. Basin Information Drainage Area I Drainage Area 2 Receiving Stream Name Little River Stream Class & Index No. QSW - 30-5-(]) Drainage Area (so 203,700 Existing Impervious* Area (so 0 Proposed Inipervious*Area (so 80,000 % Impervious* Area (total) 40 Impervious* Surface Area Drainage Area I Drainage Area 2 On -site Buildings (so 16,000 Oil -site Streets (so 0 Cn-sitc Parking (sl) 36,500 On -site Sidewalks (so 0 Other on -site (sO 27,500 Off -site (so 0 Total (so: 80,000 Forni SWU-101 Version 8.07 Page 2 of 4 Impervious area is defined as the built upon area including, but not limited to, buildings, roads, parking areas, sidewalks, gravel areas, etc. **Total project area shall be calculated based on the current policy regarding inclusion of wetlands in the built upon area percentage calculation. 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. Form DRPC-1 High Density Commercial Subdivisions Form DRPC-2 High Density Developments with Outparcels Form DRPC-3 High Density Residential Subdivisions Form DRPC4 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 Permits Unit at (919) 733-5083 for the status and availability of these forms. 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 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/Filber Strip/Restored Riparian Buffer Supplement Constructed Welland Supplement Grassed Swale Supplement Sand Filter Supplement Fonn SWU-101 Version 8.07 Page 3 of 4 vi. 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 may be found by locating project on the interactive online map at http://h2o.enr.state.ne.us/su/msi maps.ht ) 1 Please indicate that you have provided the following required information by initialing in the space provided next to each item. Initials • Original and one copy of the Stormwater Management Permit Application Form -IMF • Original and one copy of the Deed Restrictions & Protective Covenants Form _�> 0 F • Original of the applicable Supplement Form(s) d O&M agreement(s) for each BMP • Permit application processing fee of $505 ($4,000 for Express) payable to NCDENR • Calculations & detailed narrative description of stormwater treatment/ management • Copy of any applicable soil report • Three copies of plans and specifications (sealed, signed & dated), including: - Development/ Project name - Engineer and firm -Legend - North arrow Scale Revision number & date - Mean high water line - 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) VII. 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. Designated agent (individual or firm):Hobbs, Upchurch & Associates, P.A. Mailing Address:P.0 Box 1737 City:Southern Pines State:NC Zip:28388 Phone: (910 692-5616 Fax: (910 692-7342 Email: iFreeman@hobbsupghurch..com VIII. APPLICANT'S CERTIFICATION 1, (print or type name of person listed in General Information, item 2) Randy Keaton 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 15A NCAC 2H.1000. Signature: Date: C112- 7 A 12 Form SWU-101 Version 8.07 Page 4 of 4 Penh No.!�N 7o so 50 3 (b i5e pr�lded by DWQ) ,I WA rp.�q —Alr;h NCDM STORMWATER MANAGEMENT PERMIT APPLICATION FORM 401 CERTIFICATION APPLICATION FORM WET DETENTION BASIN SUPPLEMENT Ths form must be filledout, pantract andsu5mlW The Requnaxf Items CheaWl (Pal must bepninted, Medout andsubmittedalong wiO all of the requiredinbornalm If. PROJECT INFORMATION' Protect name Pasquotank County Water Plant Contact person Jeff Thornlason (Hobbs, Upchurch & Associates) Phone murnber 910-270-5520 Date 10111007 DraimeW am numi*r 1 of 1 111. DESIGN INFORMATION Site Charwtensbcs Dminagearea 180,134 ft' Impervious area 85,560 f? % impervious 47,49797373 % R EIE C V El- D. Design rainfall depth 15 in SteMeVolume: Nan-SRWaters MAY - 5 2008 Mnimunn volume requared 11,70B ft' Volume pruMed 18,087 ft' StorW Volume. SRWaters D%A1Q-WAR0 1-yr, 2"r runoff depth WA in Pre,development 1-yr, 24-hr nmoff NIA 03 Post -development 1-yi, 24-hr runoff WA a, Mnimum volume required #VALUE1 ft' Volume provided WA ft� Pod Flow Calculations Is prelpost control of the 1-yr 24-hr peak law required?. y (Y or N) I-yT, 24-hr rainlal depth 2.3 in Rational C. pre developmem 0.5 (unitless) Rational C, pod�davelopment 0.7 (unitless) Rainfall intensirlif. I-yr, 24-hr storm 4.6 HVhF Pre-duvelopment 1-yr, 24-hr peak flow 13.0 fil/sec Post-davelopmend 1-yr, 24-hr peak Dow H f0tsec PrePost 1-yr, 24-hr peak How control 75--o),a, Basin Elevations Basin bottom elevabon Ho ft Sediment cleanout elevation 100 ft Permanent pool elevation 6,00 ft Temporary pool elevation 7,00 ft Volume and Surface Area Calculations SAIDA ratio 56D unitless) Permanent pool, surface area recluged 10,087 to Permanertt pool, surface arm prowled 15,463 ft? OK Permanent pool volume 47,083 fir Average depth for SAIDA Wes 304488133 ft OK Forebay volume 10,04 ft 3 Forebay % of permanent pool volume 22 % Must be approx. 20%, Adjust pond dimensions Temporary pool. surface was provicied 19,767 ft, �rn 9VW1 -VM Dsterftn leasi�Rev, 2 �ns 1. & 11. Design Surnrnary, Page 1 d 3 Penh No.— fto be pmwdd by DWO) 111. DESIGN INFORMATION Drffwdmn Calculations Treatment volume drawdawn lime 3.3 der OK Treatment volume dsdwge rate 0.10 Ols Pre -development I -yr, 24-hr discharge 13,00 01/s OK Past-clevelolarrient 1-yr, 24-hr discharge 0,00 ftIs OK Additional khrrmation Diameter of orifice 2.00 in DesW TSS removal 90 % Basin skle slopes 3 1 OK Vegetated shelf dope 10 1 OK Vegetated shelf width 10 R OK LffKjth of ftypath to width rate 5.97 1 OK Length to width ratio 2.67 1 OK Trash rack for overflaw & ofifim? y (Y or M OK Freeboand provided I ft OK Vegetated tiler provided? n (Y or N) Design must be based on 90% TSS removal Recorded damage easement prowled? y (Y or M OK Capures all ninciff at uttimate buiWaid? y (Y or M OK Drain medwism for maintenance a emergencies limited ffVALUEI F� SVV401-VM D� Sssin-R..2 Parts 1, & I. Design Su�ry, P2ge 2 013 Perrit Jill. REQUIRED FEMS CHECKLIST (to be providiod by D10M) Please mclicate the page or plan sheel numbers where the supporting documentation can be found. An incomplete submittal package will result in a request for additional Wormation. This vivill delay fined review and approval of the project. Initial in the space provided to indicate the following design requirements have been met If the applicant has designated an agent, the agent may initial below. If a requirement has not been met attatch justification. Pagel Plan Initials Shed'No. L YEi —(0 1. Pam (1- - 50' or larger) of the enfire site showing: Design at ultimate build -out, Off-sde drainage (if applicable), Delineated drainage basins (include Rational C coefficient per basin), Basin dimensions, Pretreatment system, High flow bypass system, Maintenance access, Recorded drainage easement and public right of way (ROW), Overflow device, and Bainclanes of drainage easement 2. Partial plan (V = 30- or larger) and details for the wet detention basin showing: - Outlet structure with trash rack or similar, - Maintenance access, - Permanent pool dimensions, - Forebay and main pondwith hardened emergency spillway, - Basin cross-section, - Vegetation specification for pladng shelf, and PWTC "er " 3- Section view of the dry detention basin (1 20' or larger) showing: - Side slopes, 3:1 or lower, - Pretreatment and treatment areas, and - Inlet and outlet stuctures. 4. If the basin is used for sediment and erosion control during construction, clean out of the basin is specified on the plans prior to use as a wet detention basin. 5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay, to verify volume provided. 6. An assurance that the installed system will meet design specifications upon initial operation once the project is complete and the entire drainage area is stabilized. Ap 7. A construction sequence that shows how the wet detention basin will be protected from sediment until the entire drainage area is stabilized. 7tFCAUAh � 3 8. The supporting calculations. 9. A copy of the signed and notarized inspection and maintenance 0M) agreement. 10. A copy of the deed restriction. Forint SW401-Wet Detention BasinAev-1 Part Ill. Required Items Choclklist, Page 3 of 3 Wet Detention Basin Inspection 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. The wet detention basin system is defined as the wet detention basin, REC E-W ED pretreatment including forebays and the vegetated filter if one is provided. This system (check one): MAY - 5 2008 E] does M does not incorporate a vegetated filter at the outlet. DWQAAJARO This system (check one): F] does 0 does not incorporate pretreatment other than a forebay. Important maintenance procedures: — Immediately after the wet detention basin is established, the plants on the vegetated shelf and perimeter of the basin should be watered twice weekly if needed, until the plants become established (commonly six weeks). — No portion of the wet detention pond should be fertilized after the first initial fertilization that is required to establish the plants on the vegetated shelf. — Stable groundcover should be maintained in the drainage area to reduce the sediment load to the wet detention basin. — If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment through the emergency drain should be minin-tized to the maximum extent practical. — Once a year, a dam safety expert should inspect the embankment. After the wet detention pond is established, it should be inspected once a month and within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a Coastal County). Records of inspection and maintenance should be kept in a known set location and must 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 I will remediate the problem: The entire BMP Trash/debris is present. Remove the trash/debris. The perimeter of the wet Areas of bare soil and/or Regrade the soil if necessary to detention basin erosive gullies have formed. 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 Maintain vegetation at a height of long. approximately six inches. BMP element. Potential problem: How I will remediate the problem: The inlet device: pipe or The pipe is clogged. Unclog the pipe. Dispose of the swale sediment off -site. The pipe is cracked or Replace the pipe. otherwise damaged. Erosion is occurring in the Regrade the swale if necessary to swale. smooth it over and provide erosion control devices such as reinforced turf matting or riprap to avoid future problems with erosion. The forebay Sediment has accumulated to Search for the source of the a depth greater than the sediment and remedy the problem if original design depth for possible. Remove the sediment and sediment storage. dispose of it in a location where it will not cause impacts to streams or the BMP. Erosion has occurred. Provide additional erosion protection such as reinforced turf matting or riprap if needed to prevent future erosion problems. Weeds are present. Remove the weeds, preferably by hand. If pesticide is used, wipe it on the plants rather than spraying. The vegetated shelf Best professional practices Prune according to best professional show that pruning is needed practices to maintain optimal plant health. Plants are dead, diseased or Determine the source of the dying. problem: soils, hydrology, disease, etc. Remedy the problem and replace plants. Provide a one-time fertilizer application to establish the ground cover if a soil test indicates it is necessary. Weeds are present. Remove the weeds, preferably by hand. If pesticide is used, wipe it on the plants rather than spraying. The main treatment area Sediment has accumulated to Search for the source of the a depth greater than the sediment and remedy the problem if original design sediment possible. Remove the sediment and storage depth. dispose of it in a location where it will not cause impacts to streams or the BMP. Algal growth covers over Consult a professional to remove 50% of the area. and control the algal growth. Cattails, phragmites or other Remove the plants by wiping them invasive plants cover 50% of with pesticide (do not spray). the basin surface. BMP element: Potential problem: How I will remediate the problem: The embankment Shrubs have started to grow Remove shrubs immediately. on the embankment. Evidence of muskrat or Use traps to remove muskrats and beaver activity is present. consult a professional to remove beavers. A tree has started to grow on Consult a dam safety specialist to the embankment. remove the tree. 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 local NC Division of damage have occurred at the Water Quality Regional Office, or outlet. the 401 Oversight Unit at 919-733- 1786. The measuring device used to determine the sediment elevation shall be such that it will give an accurate depth reading and not readily penetrate into accumulated sediments. When the permanent pool depth reads 5.0 feet in the main pond, the sediment shall be removed. When the permanent pool depth reads 5.0 feet in the forebay, the sediment shall be removed. Sediment Removal Bottom BASIN DIAGRAM (fill in the blanks) Permanent Pool Elevation 6.0 1.0 � ReMajnen�Pool ........... .. Vo u Sediment Removal Elevation 1.0 Volume 0.0 ft Min. = -------------- I ------ Bottom Elevation 0.0 1-ft n \2�-sediment \ ------------- LiL� Storage Sedimer Storage FOREBAY MAIN POND I acknowledge and agree by my signature below that I am responsible for the performance of the maintenance procedures listed above. I agree to notify DWQ of any problems with the system or prior to any changes to the system or responsible party. Print name: Randy Keaton Title: Pasquotank County ManacjE�-- Address: P.O. Box 39, Elizabeth CitV, NC 27907-0039 Date: q /ftR 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, Karen S. Jenninc[s , a Notary Public for the State of -North Carolina _,County of Pasquotank I do hereby certify that - Randy Keaton personally appeared before me this 2c)t-h day of 1��ii 2-0-0-8- and acknowledge the due execution of the forgoing wet detention basin maintenance requirements. Witness my hand and official ka- r-e- C, 0 SEAL My commission expires May 18, 2012