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HomeMy WebLinkAboutSW7111105_Modification_20120822�F�A �.i_ NCDENR North Carolina Department of Environment and Natural Resources Beverly Eaves Perdue Governor Mr. Eric T. Weatherly, County of Currituck 153 Courthouse Road, Currituck, NC 27929 Dear Mr. Weatherly: Division of Water Quality Charles Wakild, PE Dee Freeman Director Secretary August 22, 2012 PE, County Engineer Suite 302 Subject: Stormwater Permit No. SW7111105 Modification Currituck Community Park & Regional Aviation and Technical Training Center Overall Low Density Commercial Development with Areas of High Density Currituck County The Washington Regional Office received a complete Stormwater Management Permit Application for the modification of Currituck Community Park and Regional Aviation and Technical Training Center on August 16, 2012. Staff review of the plans and specifications has determined that the project, as proposed, will comply with the Stormwater Regulations set forth in Session Law 2008- 211 and Title 15A NCAC 2H.1000. We are forwarding Permit No. SW7111105MOD dated August 22, 2012, for the continued construction of the subject pro1'ect. By issuance of this permit, permit SW7111105 which was issued on November 29, 2011 is hereby rescinded. This permit shall be effective from the date of issuance until November 29, 2021, 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, P.O. Drawer 27447, Raleigh, NC 27611-7447. Unless such demands are made this permit shall be final and binding. If you have any questions, or ne add'tional information concerning this matter, please contact Scott Vinson, or me at (252) 946�648,,A. V Regioha1 Supervisor Surface Water Protection Section AH/ sv: K:\WQS\STORMWATER\PERMIT\SW7111105MOD cc: Sean Robey, PE — Hyman & Robey, PC Mark Breen, PE — Site Solutions, PA Washington Regional Office North Carolina Division of Water Quality Internet: www.newaterguality.org 943 Washington Square Mall Phone: 252-946-6481 One Washington, NC 27889 FAX 252-946-9215 NorthCarolina An Equal Opportunity/AffrmativeAction Employer— 50% Recycled/10% Post Consumer Paper )Vaturally State Stormwater Management Systems Permit No. SW7111105MOD STATE OF NORTH CAROLINA DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES DIVISION OF WATER QUALITY STATE STORMWATER MANAGEMENT PERMIT OVERALL LOW DENSITY COMMERCIAL DEVELOPMENT WITH AREAS OF HIGH DENSITY 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 Currituck Currituck Community Park and Regional Aviation and Technical Training Center off NC Hwy 158, between Airport Rd. & Aviation Parkway, Barco, Currituck County FOR THE construction, operation and maintenance of an overall low density commercial development with a wet detention pond as the treatment system for Drainage Area No.2 and two constructed wetland systems for Drainage Areas No.4 & No.5, all in compliance with the provisions of Session Law 2008-211 and 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 November 29, 2021, 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. The built -upon area percentage for this 83.94 acre project is currently approved for 13.9% and must be maintained at 24% or lower per the requirements of Session Law 2008-211 and 15A NCAC 2H .1000. This project is permitted for a maximum of 508,017 square feet of built upon area consisting of 237,267 square feet for the Low Density areas of the project and 270,750 square feet for the three High Density areas within this project. 3. The stormwater systems proposed to treat the runoff generated by the designated high density areas have been approved for the management of stormwater runoff as described in Section 1.7 & 1.8 on page 3 of this permit. Page 2 of 9 State Stormwater Management Systems Permit No. SW7111105MOD 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 high density portion of the permitted drainage area of this project must be directed into the permitted stormwater control system. Within the low density portions of the permitted project, the only runoff conveyance systems allowed will be vegetated conveyances such as swales with minimum side slopes of 3:1 (H:V) as defined in the stormwater rules and as shown on the approved plans. The built -upon area for the future development is limited to 100,000 square feet within the low density drainage area #1 and 10,000 square feet within the high density drainage area #2 as set within the approved plans and application. Plans for any future built -upon area not currently shown on the approved plans must be submitted and approved by the Division prior to the start of construction. 6. The built -upon areas associated with this project shall be located at least 50 feet landward of all perennial and intermittent surface waters. 7. The following design criteria have been provided in the wet detention pond and must be maintained at design condition: Drainage Area No.2 a. Drainage Area, acres: 5 ac 4, 55s b. Total Impervious Surfaces, ft2: 6.143,555 C. Design Storm, inches: 1.50 d. Pond Depth, feet: 7.50 (4.0'average) e. TSS removal efficiency: 90% f. Permanent Pool Elevation, FMSl2: 7.00 gg Permanent Pool Surface Areq, ft : 12,800 h. Permitted Storage Volume, ft : 23,921 (at temporary pool elev) i. Temporary Storage Elevation, FMSL: 8.50 j. Predevelopment 1 year 24 hour: 1.45 cfs k. Post development 1 year 24 hour: 0.12 cfs w/control I. Controlling Orifice: 2.50" O pipe M. Permitted Forebay Volume, ft3: 7,752 n. Fountain Horsepower, HP 1/6 Hp o. Receiving Stream/River Basin: UT to North River / Pasquotank P. Stream Index Number: 30 — 2 q. Classification of Water Body: "SC" 8. The following design criteria have been provided in the two constructed wetlands and must be maintained at design condition: DA #4 DA#5 a. Drainage Area, ft2: 64,033 206,039 b. Total Impervious Surfaces, ft2: 44,867 82,328 C. Design Storm, inches: 1.50 1.50 d. Permanent Pool (PP)Elevation, FMS _ 5.50 6.00 e. Shallow Water (PP) Surface Area, ft 2,383 4,272 f. Temporary Pool TP) Elevation, F.KSL: 6.75 6.92 gg Shallow Land (T ) Surface Area, ft : 2,399 4,300 h. Deep Pool (incl Forebay) Suvace Area, ft2: 1,241 2,223 i. Required Storage Volume, ft • 5,433 10,559 1 Permitted Storage Volume, ft3: 5,433 10,559 k. Controlling Orifice: 1.50"0 1.50"0 pipes I. Receiving Stream/River Basin: UT to North River / Pasquotank M. Stream Index Number: 30-2 n. Classification of Water Body: "SC" Page 3 of 9 State Stormwater Management Systems Permit No. SW7111105MOD 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. 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 time 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. Mowin.9 and re -vegetation of slopes and the vegetated filter strip. 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, level spreader, filter strip, catch basins and piping. g. Access to the outlet structure must be available at all times. 4. Records of maintenance activities must be kept for each permitted BMP. The records will indicate the date, activity, name of person performing the work and what actions were taken. 5. Access to the stormwater facilities shall be maintained via appropriate easements at all times. 6. Decorative spray fountains will be allowed only in the wet detention basin system, sub'ect 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 this pond is 1/6 horsepower. 7. The facilities shall be constructed as shown on the approved plans. This permit shall become void unless the facilities are constructed in accordance with the conditions of this permit, the approved plans and specifications, and other supporting data. 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. 9. 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. Page 4 of 9 State Stormwater Management Systems Permit No. SW7111105MOD 10. 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. 11. 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. 12. The permittee shall submit final site layout and grading plans for any permitted future areas shown on the approved plans and receive approval prior to the start of construction. 13. A copy of the approved plans and specifications shall be maintained on file by the Permittee at all times. 14. This permit shall become void unless the facilities are constructed in accordance with the conditions of this permit, the approved plans and specifications, and other supporting data. 15. Prior to transfer of the permit, the stormwater facilities will be inspected by DWQ personnel. The facility must be in compliance with all permit conditions. Any items not in compliance must be repaired or replaced to design condition prior to the transfer. Records of maintenance activities performed to date will be required. 16. Prior to the subdivision and/or sale of this project, in whole or in part, the following deed restrictions must be recorded with the Office of the Register of Deeds: a. The following covenants are intended to ensure ongoing compliance with State Stormwater Management Permit Number SW7111105, as issued by the Division of Water Quality under NCAC 2H.1000. b. The State of North Carolina is made a beneficiary of these covenants to the extent necessary to maintain compliance with the Stormwater Management Permit. C. These covenants are to run with the land and be binding on all persons and parties claiming under them. d. The covenants pertaining to stormwater may not be altered or rescinded without the express written consent of the State of North Carolina, Division of Water Quality. e. Alteration of the drainage as shown on the approved plans may not take place without the concurrence of the Division of Water Quality. Page 5 of 9 State Stormwater Management Systems Permit No. SW7111105MOD f. This project is permitted for a maximum of 508,017 square feet of built -upon area. Construction of additional built -upon area in excess of this amount will require a permit modification. g. This project may riot be sold or subdivided, in whole or in part, without first receiving a permit modification from the Division. h. Construction of additional impervious areas such that low -density requirements are no longer met will require a permit modification prior to construction. An engineered system will be required to collect and treat the runoff from all built -upon area associated with the project, including that area permitted under the low density option. i. Filling in or piping of any vegetative conveyances (ditches, swales, etc.) associated with this development, except for average driveway crossings, is strictly prohibited by any persons. j. The built -upon areas shall be located a minimum of 50 feet landward of all perennial and intermittent surface waters. 17. A copy of the recorded deed restrictions must be submitted to the Division within 30 days of the date of recording the plat, and prior to selling lots. The recorded copy must contain all of the statements above, the signature of the Permittee, the deed book number and page, and the stamp/signature of the Register of Deeds. III. 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 completed Name/Ownership Change form, to the Division of Water Quality, signed by both parties, and accompanied by supporting documentation as listed on page 2 of the form. The project must be in good standing with the Division. The approval of this request will be considered on its merits and may or may not be approved. 2. The permittee is responsible for compliance with all permit conditions until such time as the Division approves the transfer request. 3. 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. 4. 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. 5. 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. 6. 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. 7. The permit issued shall continue in force and effect until revoked or terminated. The permit may be modified, revoked and reissued or terminated for cause. The filing of a request for a permit modification, revocation and re -issuance or termination does not stay any permit condition. Page 6 of 9 State Stormwater Management Systems Permit No. SW7111105MOD 8. 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. 9. Approved plans and specifications for this project are incorporated by reference and are enforceable parts of the permit. 10. The issuance of this permit does not prohibit the Director from reopening and modifying the permit, revoking and reissuing the permit, or terminating the permit as allowed by the laws, rules and regulations contained in Session Law 2008- 211, Title 15A NCAC 21-1.1000, and NCGS 143-215.1 et.al. 11. The permittee shall notify the Division of any name, ownership or mailing address changes at least 30 days prior to making such changes. 12. This permit shall be effective from the date of issuance until November 29, 2021. 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. Permit issued this the 22nd day of August, 2012. ENVIRONMENTAL MANAGEMENT COMMISSION for Division of Water Quality By Authority of the Environmental Management Commission Stormwater Permit No. SW7111105 Modification Page 7 of 9 State Stormwater Management Systems Permit No. SW7111105MOD Currituck Community Park & Regional Aviation & Technical Training Center Stormwater Permit No. SW7111105 Modification Currituck 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 8 of 9 State Stormwater Management Systems Permit No. SW7111105MOD 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 Washington Regional Office Currituck County Planning/Building Inspections Page 9 of 9