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HomeMy WebLinkAboutSW8040346_CURRENT PERMIT_20061120STORMWATER DIVISION CODING SHEET POST -CONSTRUCTION PERMITS PERMIT NO. SW8 Olio b Ly DOC TYPE] CURRENT PERMIT ❑ APPROVED PLANS ❑ HISTORICAL FILE ❑ COMPLIANCE EVALUATION INSPECTION DOC DATE 2 O OlD 1120 YYYYMMDD Michael F. Easley, Governor William G. Ross Jr., Secretary North Carolina Department of Environment and Natural Resources Alan W. Klimek, P.E. Director Division of Water Quality November 20, 2006 Larry Faison, Town Manager Town of Swansboro 502 Church Street Swansboro, NC 28584 Subject: Stormwater Permit No. SW8 040346 Mod. Town of Swansboro WWTP Site and Low Rate Infiltration Basin Site for Reclaimed Water Main Extension Overall Low Density Project with pockets of High Density Onslow County Dear Mr. Faison: The Wilmington Regional Office received a complete Stormwater Management Permit Application for the Town of Swansboro WWTP Site & Reclaimed Water Main Extension on November 15, 2006. 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 21-1.1000. We are forwarding Permit No. SW8 040346 Mod. dated November 20 2006, for the construction of the subject project. This permit shall be effective from the date of issuance until November 20, 2016, 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 sixty (60) days following receipt of this permit. This request must be in the form of a written petition, conforming to Chapter 150E 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 need additional information contact Linda Lewis, or me at (910) 796-7215. Sincer Edward Beck Regional Supervisor Surface Water Protection Section concerning this matter, please ENB/arl: S:\WQS\STORMWATER\PERMIT\040346.nov06 cc: Landon Younce, P.E., Green Engineering Onslow County Building Inspections Doug Huggett, DCM Linda Lewis Wilmington Regional Office Central Files North Carolina aNatura!!y North Carolina Division of Water Quality 127 Cardinal Drive Extension Wilmington, NC 28405 Phone (910) 796-7215 Wilmington Regional Office Internet: www ncwatcrouahty ore Fax (910) 350-2004 An Equal Dpportunity/AffrmaLve Action Employer— 50% Recycled110°/ Post Consumer Paper Customer Service 1-87 7-623-6748 State Stormwater Management Systems Permit No. SW8 040346 Mod. 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 Town of Swansboro WWTP Site & Low Rate Infiltration Basin Site for Reclaimed Water Main Extension NCSR 1512 (WWTP site) & NCSR 1432 (Low Rate Infiltration Basin Site.) Onslow County FOR THE construction, operation and maintenance of two (2) wet detention ponds at the WWTP site and overall 30% low density at the Low Rate Infiltration Basin site, 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 November 20, 2016, and shall be subject to the following specified conditions and limitations: I. DESIGN STANDARDS This permit is effective only with respect to the nature and volume of stormwater described in the application and other supporting data. The stormwater systems have been approved for the management of stormwater runoff as described in Section 1.6 on page 3 of this permit. The stormwater controls numbered Pond 1 anq Pond 2 have �een designed to handle the runoff from a maximum of 55,500 ft and 20,000 ft , respectively, of impervious area. The 16.3 acre WWTP tract will be limited to no more than 75,500 ft2 of built -upon area. The 210.8 acre Low Rate Infiltration Basin Site for tP Reclaimed Water Main Extension project will be limited to no more than 95,973 ft of built -upon area for a 12' wide gravel access road. The built -upon area for the fyture development draining to Ponds 1 and 2 on the WWTP tract is limited to 5,960 ft and 8,000 ft , respectively. 4. All stormwater collection piping, swales, and treatment systems must be located in either dedicated common areas or recorded easements, as necessary. The final plats for the project will be recorded showing all such required easements, in accordance with the approved plans. Page 2 of 7 State Stormwater Management Systems Permit No. SW8 040346 Mod. 61 A 91 The runoff from all built -upon area within the permitted drainage areas of the WWTP site must be directed into the appropriate permitted stormwater control system. The following design criteria have been provided in the wet detention ponds and must be maintained at design condition: a. Drainage Area, acres: Onsite, ft : Offsite, ft2: b. Total Impervious Surfaces, ftz: C. Design Storm, inches: d. Pond Depth, feet: e. TSS removal efficiency: f. Permanent Pool Elevation, FMSI : g. Permanent Pool Surface Areq, ft h. Permitted Storage Volume, ft : i. Temporary Storage Elevation, FMSL: j. Controlling Orifice: k. Permitted Forebay Volume, ft3: I. Max. Fountain Horsepower: M. Receiving Stream/River Basin: n. Stream Index Number: o. Classification of Water Body: Pond 1 Pond 2 5.10 1.84 222,000 80,000 0 0 55,500 20,000 1.0 1.0 4.0 4.0 90% 90% 15.0 19.0 5,000 3,888 5,496 4,324 16.0 20.0 1"0 pipe 0.5" 0 pipe 1,565 1,000 1/8 1/8 Foster Creek / White Oak W OK01 20-35 "SC Within the Low Rate Infiltration Basin site, 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 approved by the Division. Within the Low Rate Infiltration Basin site, no piping is allowed except that minimum amount necessary to direct runoff beneath an impervious surface such as a road. 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 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. Mowin.9 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. Page 3 of 7 State Stormwater Management Systems Permit No. SW8 040346 Mod. 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 void unless the facilities are constructed in accordance with the conditions of this permit, the approved plans and specifications, and other supporting data. If the stormwater systems are used as Erosion Control devices, they must be restored to design condition prior to operation as a stormwater treatment device. 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 fora fountain in this pond is listed in Section 1.6 (1) of this permit. 8. 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. Access to the stormwater facilities shall be maintained via appropriate easements at all times. 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 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 Permittee for a minimum of ten years from the date of the completion of construction. Page 4 of 7 State Stormwater Management Systems Permit No. SW8 040346 Mod. 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. III. GENERAL CONDITIONS This permit is not transferable to any person or entity 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, such as recorded deed restrictions, Designer's Certification, and signed Operation and Maintenance plans. 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 in writing of any name, ownership or mailing address changes within 30 days. Permit issued this the 20th day of November 2006. NORTH OLINA ENVIRONMENTAL MANAGEMENT COMMISSION Division of Water Quality By Authority of the Environmental Management Commission Page 5 of 7 State Stormwater Management Systems Permit No. SW8 040346 Mod. Town of Swansboro WWTP Site and Low Rate Infiltration Basin Site for Reclaimed Water Main Ext. Stormwater Permit No. SW8 040436 Mod. Onslow 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 6 of 7 State Stormwater Management Systems Permit No. SW8 040346 Mod. 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 Onslow County Building Inspections Page 7 of 7 OFFICE USE ONLY Date Received Fee Paid Permit Number Z 00p.00 01-7t o is O L4 0 State of North Carolina Department of Environment and Natural Resources Division of Water Quality STORMWATER MANAGEMENT PERMIT APPLICATION FORM This form may be photocopied for use as an original I. GENERAL INFORMATION 1. Applicants name(specify the name of the corporation, individual, etc. who owns the project): Town of Swansboro 2. Print Owner/Signing Official's name and title (person legally responsible for facility and compliance): Larry Faison - Manager, Town of Swansboro 3. Mailing Address for person listed in item 2 above: 502 Church Street City: Swansboro State: N.C. Zip: 28584 Telephone Number: (910) 326-4428 Fax Number: (910) 326-3101 4. Project Name (subdivision, facility, or establishment name - should be consistent with project name on plans, specifications, letters, operation and maintenance agreements, etc.): Wastewater Treatment Plant Improvements - Town of Swansboro 5. Location of Project (street address): SR 1512 (Old Hammocks Road), SR 1432 (Parker Town City: Swansboro 6. Directions to project (from nearest major intersection): Approximately 0.25 miles southeast of the intersection of SR 1511 and SR 1512 at the Town of 7. Latitude: 34° 40'56% 34° 43'44" Longitude: 77° 08'34", 77° 12'32" of project 8. Contact person who can answer question about the project: Name: W. Landon Younce, P.E. Telephone Numbers: (252) 237-5365 It. PERMIT INFORMATION: 1. Specify whether project is (check one): From SWU-101 Version 3.99 New Renewal X Modification Page 1 of 4 2. If this application is being submitted as the result of a renewal or modification to an existing permit, list the existing permit number SW8 040346 and its issue date (if known) January 12, 2005 3. Specify the type of project (check one): X Low Density High Density Redevelop General Permit other 4. Additional Project Requirements (check applicable blanks): X CAMA General X Sedimentation/Erosion Control X 404/401 Permit NPDES Stormwater Information on required state permits can be obtained by contacting the Customer Service Center at 1-877-623-6748. 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. Stormwater is currently routed to an existing stormwater collection system serving the WWTP site. Stormwater is allowed to sheet flow off site into wetlands at the reclaimed water low -rate infiltration 2. Stormwater runoff from this project drains to the White Oak River basin. 3. Total Project Area: 5.1, 1.8, 210.8 acres 4. Project Built Upon Area: 25.00, 25.00, 1.05 % 5. How many drainage areas does the project have? 3 (#1 8 #2 at the WWTP, #3 at the Disposal Site) 6. Complete the following information for each drainage area. If there are more that two drainage areas in the project, attach an additional sheet with the information for each area provided in the same format as below. Basin Information Drainage Area 1 Drainage Area 2 Drainage Area 3 Receiving Stream Name Foster's Creek Foster's Creek Pasture Branch Receiving Stream Class SC SC SA; HQW Drainage Area 222,000 s.f. 80,000 s.f. 9,183,300 s.f. Existing Impervious * Area 43,340 s.t. 0 s.f. 56,373 s.f. Proposed Impervious *Area 12,160 s.f. 20,000 s.f. 39,600 s.f. % Impervious * Area total 25.00% 25.00% 1.05% Impervious * Surface Area Drainage Area 1 'Drainage Area'2 Drainage Area 3 On -site Buildings 3,713 s.f. --- --- On-site Streets 41,004 s.f. 12,000 s.f. 95,973 s.f. gravel dr. On -site Parkin --- --- --- On-site Sidewalks 4,823 s.f. --- --- Other on -site Future B.U.A. 5,960 s.f. 8,000 s.f. --- Off-site --- --- --- Total: 55,500 s.f. Total: 20,000 s.f. Total: 95,973 s.f. *Impervious area is defined as the built upon area including, but not limited to, buildings, roads, parking areas, sidewalks, gravel areas, etc. Page 2 of 4 Form SWU-101 Version 3.99 7. How was the off -site impervious area listed above derived? N/A - offsfte area is undeveloped IV. DEED RESTRICTIONS AND PROTECTIVE COVENANTS The following italicized 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 table listing each lot number, size and the allowable built -upon area for each lot must be provided as an attachment. 1. The following covenants are intended to ensure ongoing compliance with state stormwater management permit number as issued by the Division of Water Quality. These covenants may not be changed or deleted without the consent of the State. 2. No more than square feet of any lot shall be covered by structures or impervious materials. Impervious materials include asphalt, gravel, concrete, brick, stone, slate or similar material but do not include wood decking or the water surface of swimming pools. 3. Swales shall not be filled in, piped, or altered except as necessary to provide driveway crossings. 4. Built -upon area in excess of the permitted amount requires a state stormwater management permit modification prior to construction. 5. All permitted runoff from outparcels or future development shall be directed into the permitted stormwater control system. These connections to the stormwater control system shall be performed in a manner that maintains the integrity and performance of the system as permitted. By your signature below, you certify that the recorded deed restrictions and protective covenants for this project shall include all the applicable items required above, that the covenants will be binding on all parties and persons claming 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 SWU-102 Wet Detention Basin Supplement Form SWU-103 Infiltration Basin Supplement Form SWU-104 Low Density Supplement Form SWU-105 Curb Outlet System Supplement Form SWU-106 Off -Site System Supplement Form SWU-107 Underground Infiltration Trench Supplement Form SWU-108 Neuse River Basin Supplement Form SWU-109 Innovative Best Management Practice Supplement Page 3 of 4 Form SWU-101 Version 3.99 t 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 Regional Office. Please indicated 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 • One copy of the applicable Supplement Form(s) for each BMP • Permit application processing fee of $420 (payable to NCDENR) • Detailed narrative description of stormwater treatment/management • Two copies of plans and specifications, 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 or 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): Green Engineering, P.L.L.C. Mailing Address: 303 N. Goldsboro Street, P.O. Box 609 City: Wilson State: N.C. Zip: 27893 Phone: (252) 237-5365 Fax: (252) 243-7489 Vill. APPLICANTS CERTIFICATION 1, (print or type name of person listed in General Information, item 2) Larry Faison 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 recorded, and that the proposed project complies with the requirements of 15A NCAC 2H .1000 JC / Signature: C Date: �` L /> Page 4 of 4 Form SWU-101 Version 3.99 If this application is being submitted as the result of a renewal or modification to an existing permit, list the existing permit number SW8 040346 and its issue date (if known) January 12, 2005 3. Specify the type of project (check one): X Low Density High Density Redevelop General Permit other 4. Additional Project Requirements (check applicable blanks): X CAMA General X Sedimentation/Erosion Control X 404/401 Permit NPDES Stormwater Information on required state permits can be obtained by contacting the Customer Service Center at 1-877-623-6748. 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 is currently routed to an existing stormwater collection system serving the WWTP site. Stormwater is allowed to sheet flow off site into wetlands at the reclaimed water low -rate infiltration basin disposal site. 2 Stormwater runoff from this project drains to the White Oak River basin. 3. Total Project Area: 5.1, 1.8, 210.8 acres 4. Project Built Upon Area: 22.32, 15.00, 1.05 % 5. How many drainage areas does the project have? 3 (#1 & #2 at the WWTP, #3 at the Disposal Site) 6. Complete the following information for each drainage area. If there are more that two drainage areas in the project, attach an additional sheet with the information for each area provided in the same format as below. Basin Information Drainage Area 1 Drainage Area 2 Drainage Area 3 Receiving Stream Name Foster's Creek Foster's Creek Pasture Branch Receiving Stream Class SC SC SA; HQW Drainage Area 222,000 s.f. 80,000 s.f. 9,183,300 s.f. Existing Impervious ' Area 43,340 s.f. 0 s.f. 56,373 s.f. Proposed Impervious * Area 6,200 s.f. 12,000 s.f. 39,600 s.f. % Impervious ' Area total 22.32% 15.00% 1.05% Impervious ' Surface Area Drainage Area 1 Drainage Area 2 Drainage Area 3 On -site Buildings 31713 s.f. --- --- On-site Streets 41,004 s.f. 12,000 s.f. 95;973 s.f.( ravel dr. On -site Parking --- --- On-site Sidewalks 4,823 s.f. --- --- Other on -site --- --- Off-site --- --- --- Total: 49,540 s.f. Total: 12,000 s.f. Total: 95,973 s.f. 'Impervious area is defined as the built upon area including, but not limited to, buildings, roads, parking areas, sidewalks, gravel areas, etc. Page 2 of 4 Form SWU-101 Version 399 Permit No. SGu 870 ¢034 � (to be provided by DWQ) State of North Carolina Department of Environment and Natural Resources Division of Water Quality STORMWATER MANAGEMENT PERMIT APPLICATION FORM WET DETENTION BASIN SUPPLEMENT POND No. I This form may be photocopied for use as an original DWO Stormwater Management Plan Review: A complete stormwater management plan submittal includes an application form, a wet detention basin supplement for each basin, design calculations, and plans and specifications showing all basin and outlet structure details. I. PROJECT INFORMATION Project Name: Wastewater Treatment Plant Improvements -Town of Swansboro WWTP Pond No. 1 Contact Person: Larry Faison, Manager Phone Number: ( 910 ) 326-4428 For projects with multiple basins, specify which basin this worksheet applies to: Foster's Creek (No. 1) elevations POND No. I Basin Bottom Elevation 11.00 ft. (floor of the basin) Permanent Pool Elevation 15.00 ft. (elevation of the orifice) Temporary Pool Elevation 16.00 ft. (elevation of the discharge structure overflow) areas Permanent Pool Surface Area Drainage Area Impervious Area volumes 5,000 sq.ft. 5.1 ac. 1.1 ac. (water surface area at the orifice elevation) (on -site and off -site drainage to the basin) (on -site and off -site drainage to the basin) Permanent Pool Volume 7,466 cu. ft. (combined volume of main basin andforebay) Temporary Pool Volume 5,496 CU. ft. (volume detained above the permanent pool) Forebay Volume 1,565 cu. ft. (approximately 20% of total volume) other parameters SA/DA 1 2.25 (surface area to drainage area ratio from DWQ table) Diameter of Orifice 1.0 in. (2 to 5 day temporary pool draw -down required) Design Rainfall LO in. Design TSS Removal 2 90 % (minimum 85%required) Form SWU-102 Rev 3.99 Page I of a Footnotes: When using the Division SA/DA tables, the correct SA/DA ratio for permanent pool sizing should be computed based upon the actual impervious %and permanent pool depth. Linear interpolation should be employed to determine the correct value for not standard table entries. In the 20 coastal counties, the requirement for a vegetative filter may be waived if the wet detention basin is designed to provide 90%TSS removal. The NCDENR BMP manual provides design tables for both 85%TSS removal and 90%TSS removal. IL REQUIRED ITEMS CHECKLIST The following checklist outlines design requirements per the Stormwater Best Management Practices Manual (N.C. Department of Environment, Health and Natural Resources, February 1999) and Administrative Code Section: 15A NCAC 2H .1008. Initial in the space provided to indicate the following design requirements have been met and supporting documentation is attached. If the applicant has designated an agent in the Stormwater Management Permit Application Form, the agent may initial below. If a requirement has not been met, attach justification. a. b. C. d. e. The permanent pool depth is between 3 and 6 feet (required minimum of 3 feet). The forebay volume is approximately equal to 20% of the basin volume. The temporary pool controls runoff from the design storm event. The temporary pool draws down in 2 to 5 days. If required, a 30 foot vegetative filter is provided at the outlet (include non -erosive flow calculations) The basin length to width ratio is greater that 3:1. The basin side slopes above the permanent pool are no steeper than 3:1 A submerged and vegetated perimeter shelf with a slope of 6:1 or less (show detail). Vegetative cover above the permanent pool elevation is specified. A trash rack or similar device is provided for both the overflow and orifice. A recorded drainage easement is provided for each basin including access to nearest right-of-way. If the basin is used for sediment and erosion control during construction, clean out of the basin is specified prior to use as a wet detention basin. in. A mechanism is specified which will drain the basin for maintenance or an emergency. III. WET DETENTION BASIN OPERATION AND MAINTENANCE AGREEMENT The wet detention basin system is defined as the wet detention basin, pretreatment including forebays and the vegetated filter if one is provided. This system (check one) does X does not incorporate a vegetated filter at the outlet. This system (check one) does X does not incorporate pretreatment other than a forebay. Forth SWU-102 Rev 3 99 Page 2 of WU 111006 Maintenance activities shall be performed as follows: 1. After every significant runoff producing rainfall event and at least monthly: a. Inspect the wet detention basin system for sediment accumulation, erosion, trash accumulation, vegetated cover, and general condition. b. Check and clear the orifice of any obstructions such that drawdown of the temporary pool occurs within 2 to 5 days as designed. 2. Repair eroded areas immediately, re -seed as necessary to maintain good vegetative cover, mow vegetative cover to maintain a maximum height of six inches, and remove trash as needed. 3. Inspect and repair the collection system (i.e. catch basins, piping, swales, riprap, etc.) quarterly to maintain proper functioning. 4. Remove accumulated sediment from the wet detention basin system semi-annually or when depth is reduced to 75% of the original design depth (see diagram below). Removed sediment shall be disposed of in an appropriate manner and shall be handled in a manner that will not adversely impact water quality (i.e. stockpiling near a wet detention basin or stream, etc.). The measuring device used to determine the sediment elevation shall be such that it will give an accurate depth reading and not readily penetrate into accumulated sediments. When the permanent pool depth reads 3.0 feet in the main pond, the sediment shall be removed. When the permanent pool depth reads Sediment t: 7 EL 12.00 on 11.00 FOREBAY 3.0 feet in the forebay, the sediment shall be removed. BASIN DIAGRAM (fill in the blanks) permanent Pool Elevation 15.00 Sediment Removal Elevation 12.00 Bottom Elevation) I .00 ♦ 255E 5. Remove cattails and other indigenous wetland plants when they cover 50% of the basin surface. These plants shall be encouraged to grow along the vegetated shelf and forebay berm. 6. If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment through the emergency drain shall be minimized to the maximum extent practical. Form SWU-102 Rev 3 99 Page 3 of 7. All components of the wet detention basin system shall be maintained in good working order. I acknowledge and agree by my signature below that I am responsible for the performance of the seven maintenance procedures listed above. I agree to notify DWQ of any problems with the system or prior to any changes to the system or responsible party. Print Name: Larry Faison Title: Manager - Town of Swansboro, N.C. Address: 502 Church Street, Swansboro, N.C. 28584 Phone: (910) 326-4428 Signature: Date: Note: The legally responsible party should not be a homeowners association unless more than 50%of the lots have been sold an a resident of the subdivision as been named the president. 1, C : I Ic. ,r a Notary Public for the State of Jy e County of Uw51oL > , do hereby certify that i-5 av, personally appeared before me thisZI�A day of c mac,,,- i �y .� , and acknowledge the due execution of the forgoing wet detention basin maintenance requirements. Witness my hand and official seal, .'-N,W �. p a► `°_ ar AL My commission expires MYCOa8MOMON EMM 9rp9Q Form SWU-102 Rev. 399 Page 4 of Permit No. S&O R) 4-'033 -G (to be provided by DWQ) State of North Carolina Department of Environment and Natural Resources Division of Water Quality STORMWATER MANAGEMENT PERMIT APPLICATION FORM WET DETENTION BASIN SUPPLEMENT POND No. 2 Thu form may be photocopied for use as an original DWO Stormwater Management Plan Review: A complete stormwater management plan submittal includes an application form, a wet detention basin supplement for each basin, design calculations, and plans and specifications showing all basin and outlet structure details. I. PROJECT INFORMATION Project Name: Wastewater Treatment Plant Improvements -Town of Swansboro WWTP Pond No. 2 Contact Person: Larry Faison, Manager Phone Number:( 910 ) 3264428 For projects with multiple basins, specify which basin this worksheet applies to: Foster's Creek (No. 2) elevations Basin Bottom Elevation Permanent Pool Elevation Temporary Pool Elevation areas Permanent Pool Surface Area Drainage Area Impervious Area volumes Permanent Pool Volume Temporary Pool Volume Forebay Volume other parameters SA/DA I Diameter of Orifice Design Rainfall Design TSS Removal 2 POND No. 2 15.00 ft. 19.00 ft. 20.00 ft. 3,888 sq. ft. 1.8 ac. 0.28 ac. (floor of the basin) (elevation of the orifice) (elevation of the discharge structure overflow) (water surface area at the orifice elevation) (on -site and off -site drainage to the basin) (on -site and off -site drainage to the basin) 5,923 cu. ft. (combined volume of main basin andforebay) 4,106 cu. ft. (volume detained above the permanent pool) 1,069 CU. ft. (approximately 20% of total volume) 2.25 (surface area to drainage area ratio from DWQ table) 0.5 in. (2 to 5 day temporary pool draw -down required) 1.0 in. 90 % (minimum 85% required) Form SWU-102 Rev. 3 99 Page I of Footnotes: When using the Division SAIDA tables, the correct SAIDA ratio for permanent pool suing should be computed based upon the actual impervious %and permanent pool depth. Linear interpolation should be employed to determine the correct value for not standard table entries. In the 20 coastal counties, the requirement for a vegetative filter may be waived if the wet detention basin is designed to provide 90%TSS removal. The NCDENR BMP manual provides design tables for both 85%TSS removal and 90% TSS removal. II. REQUIRED ITEMS CHECKLIST The following checklist outlines design requirements per the Stormwater Best Management Practices Manual (N.C. Department of Environment, Health and Natural Resources, February 1999) and Administrative Code Section: 15A NCAC 2H .1008. Initial in the space provided to indicate the following design requirements have been met and supporting documentation is attached. If the applicant has designated an agent in the Stormwater Management Permit Application Form, the agent may initial below. If a requirement has not been met, attach justification. Applicants Initials M?_ 1 0'. FIA The permanent pool depth is between 3 and 6 feet (required minimum of 3 feet). The forebay volume is approximately equal to 20% of the basin volume. The temporary pool controls runoff from the design storm event. The temporary pool draws down in 2 to 5 days. If required, a 30 foot vegetative filter is provided at the outlet (include non -erosive flow calculations) The basin length to width ratio is greater that 3:1. The basin side slopes above the permanent pool are no steeper than 3:1 A submerged and vegetated perimeter shelf with a slope of 6:1 or less (show detail). Vegetative cover above the permanent pool elevation is specified. A trash rack or similar device is provided for both the overflow and orifice. A recorded drainage easement is provided for each basin including access to nearest right-of-way. If the basin is used for sediment and erosion control during construction, clean out of the basin is specified prior to use as a wet detention basin. A mechanism is specified which will drain the basin for maintenance or an emergency. HI. WET DETENTION BASIN OPERATION AND MAINTENANCE AGREEMENT The wet detention basin system is defined as the wet detention basin, pretreatment including forebays and the vegetated filter if one is provided. This system (check one) does X does not incorporate a vegetated filter at the outlet. This system (check one) does X does not incorporate pretreatment other than a forebay. Form SWU-102 Rev 399 Page 2 of Maintenance activities shall be perfonned as follows: 1. After every significant runoff producing rainfall event and at least monthly: a. Inspect the wet detention basin system for sediment accumulation, erosion, trash accumulation, vegetated cover, and general condition. b. Check and clear the orifice of any obstructions such that drawdown of the temporary pool occurs within 2 to 5 days as designed. 2. Repair eroded areas immediately, re -seed as necessary to maintain good vegetative cover, mow vegetative cover to maintain a maximum height of six inches, and remove trash as needed. 3. Inspect and repair the collection system (i.e. catch basins, piping, swales, riprap, etc.) quarterly to maintain proper functioning. 4. Remove accumulated sediment from the wet detention basin system semi-annually or when depth is reduced to 75% of the original design depth (see diagram below). Removed sediment shall be disposed of in an appropriate manner and shall be handled in a manner that will not adversely impact water quality (i.e. stockpiling near a wet detention basin or stream, etc.). The measuring device used to determine the sediment elevation shall be such that it will give an accurate depth reading and not readily penetrate into accumulated sediments. When the permanent pool depth reads 3.0 feet in the main pond, the sediment shall be removed. When the permanent pool depth reads Sediment "oval El. 16. 00 3.0 feet in the forebay, the sediment shall be removed. BASIN DIAGRAM (fill in the blanks) Permanent Pool Elevation 19.00 Sediment Removal Elevation 16.00 755E --------------------------- --- Bottom Elevation 15.00 25* FOREBAY MAIN POND 5. Remove cattails and other indigenous wetland plants when they cover 50% of the basin surface. These plants shall be encouraged to grow along the vegetated shelf and forebay berm. 6. If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment through the emergency drain shall be minimized to the maximum extent practical. Forth SWU-102 Rev 3.99 Page 3of4 7. All components of the wet detention basin system shall be maintained in good working order. 1 acknowledge and agree by my signature below that 1 am responsible for the performance of the seven maintenance procedures listed above. 1 agree to notify DWQ of any problems with the system or prior to any changes to the system or responsible party. Print Name: Larry Faison Title: Manager - Town ofSwansboro, N.C. Address: 502 Church Street, Swansboro, N.C. 28584 Phon Signz Date: Note: The legally responsible party should not be a homeowners association unless more than 500%of the lots have been sold an a resident of the subdivision has been named the president. 1, _ -� , a Notary Public for the State of �\t C� County of h,gl �, do hereby certify that C ; ao,--, personally appeared before me this day of 1�v 4�_ , Zoa(p, and acknowledge the due execution of the forgoing wet detention basin maintenance requirements. Witness my hand and official seal, Cal AIR O v" '*how 1J104' SEAL My commission expires MY COMMISSION EXPIRES 1/30J2011 Forth SWU-102 Rev. 3.99 Page 4 of 1i11^111i//,o', '►►►8hrtnr•••`� Permit No. :�w ;?G o 3 4'60 (lobe provided by DWQ) State of North Carolina Department of Environment and Natural Resource Division of Water Quality STORMWATER MANAGEMENT PERMIT APPLICATION FORM CURB OUTLET SYSTEM SUPPLEMENT FOR LOW DENSITY DEVELOPMENT WITH CURB AND GUTTER This form may be pholocopied for use man original DWQ Stormwater Management Plan Review: A complete stormwater management plan submittal includes a stormwater management permit application, a curb outlet system supplement, a low density supplement, design calculations, and plans and specifications showing all stormwater conveyances and curb outlet details. I. PROJECT INFORMATION Project Name: Wastewater Treatment Plant Improvements - Town ofSwansboro Contact Person: W. Landon Younce, P.E. Phone Number: (252) 237-5365 Curb outlets to (check one ) ©Swale Vegetated Area II. REQUIRED ITEMS CHECKLIST The following checklist outlines design requirements per the North Carolina Administrative Code Section 15A NCAC 2H .1008. Initial in the space provided to indicate that the following design requirements have been met and supporting documentation is attached. If the applicant has designated an agent on the Stormwater Management Permit Application Form, the agent may initial below. If a requirement has not been met, attach justification. Applicants Initials S#t— a. Curb outlets direct flow to a swale or vegetated area. b. Swales or vegetated areas receiving curb outlet flow are designed to carry, at a minimum, the peak flow from the I0-year storm. c. Flow velocity is non -erosive for peak flow from the 10-year storm event. d. Longitudinal slope of the swale or vegetated area does not exceed 5%. e. Side slopes of the swale or vegetated area are no steeper than 5:1 (horizontal to vertical). f. Length of swale or vegetated area is> 100 feet. g. The system takes into account the run-off at ultimate built -out potential from all surfaces draining to the system (delineate drainage area for each swale). h. Swales are located in recorded drainage easements. I. Grass type(s) for permanent vegetative cover specified on detail. �— j. Swale detail provided on plans. Page I of 3 Form SWU-105 Ver 3.99 XO/421/04 THU 13:53 FAX 252 243 7489 GREEN ENGINEERING 2002 111. DESIGN INFORMATION Complete the following table_ if additional space is needed the information should be provided in the same format as Table 1 and attached to this form. Rainfall intensity data can be found in Appendix 8.03 of the State of North Carolina Erosion and Sediment Control Planning and Design Manual. T2610 I Cwaln 11xion Infnrt atinn Swale No, Drainage, Area ac ,linper4ious, Area ac :, rassed.;.; :Area ac ', .:' C;: .,....Q .:. ":'::' .:.':. ..: cfs V.,allow`"'V'actual s . 1:...(fps):: -- Flow Do ith $' 1 0.59 0.10 0.49 0.70 3.30 4.0 1.5 0,67 2 0.83 0.20 0.63 0.70 4.10 40 0.88 0.25 3 4 5 6 7 R 9 10 I 12 13 14 15 16 17 1R 19 20 21 22 23 24 25 Page 2 of 3 Form SWU-105 Ver3.99 Ill. CURB OUTLET SYSTEM MAINTENANCE REQUIREMENTS Mowing will be accomplished as needed according to the season. Grass height will not exceed six inches at any time. 2. Swales will be inspected monthly or after every runoff producing rainfall event for sediment build-up, erosion, and trash accumulation. 3. Accumulated sediment and trash will be removed as necessary. Swales will be reseeded or sodded following sediment removal. 4. Eroded areas of the swales will be repaired and reseeded. Swales will be revegetated as needed and in a timely manner based on the monthly inspections. 5. Catch basins, curb cuts, velocity reduction devices, and piping will be inspected monthly or after every significant runoff producing rainfall event. Trash and debris will be cleared away from grates, curb cuts, velocity reduction devices and piping. 6. Swales will not be altered, piped, or filled in without approval from NCDENR Division of Water Quality I acknowledge and agree by my signature below that I am responsible for the performance of the six 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 and Title: Larry Faison -Manager, Town ofSwansboro, N.C. Address: Phone: Signature: 502 Church 326-4428 North Carolina 28584 Date: 717, L/D 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. 5 • A l Q Q - Y . a Notary Public for the State of A10, , County of do maintenance requirements. WimeA my SEAL �\\\\ 'tSR l ..... _ �: .�pTAq •.s 'OUBL\G seal, My Page 3 of 3 appeared before me this in of the forg�joing infiltration basin 'esLV" /• O-7 Form SWU-105 Ver 3.99 State Stormwater Management Systems Permit No. SW8-040346 Mod. Town of Swansboro WWTP Site and Low Rate Infiltration Basin Site for Reclaimed Water Main Ext. Stormwater Permit No. SW8 040436 Mod. Onslow County Designer's Certification I, W. Landon Younce, P.E. as a duly registered Professional Engineer in the State of North Carolina, having been authorized to observe (periodically, weekly, full time the construction of the project, Town of Swansboro Wastewater Treatment Plant and Reclaimed Water Low Rate Infiltration Basin Disposal Facility (Project) for the Town of Swansboro (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 forth is included in the Certification. Noted deviations from approved plans and specification: FED 2 6 2009 BY: Registration Number_ Date December 15, 2008 Page 1 of 2 P 1SWMSTW472St .W. Cc fio. Canlnq 1.7,1 R 4(12.1548))d SEAL r. � , . .., � .. ,.. ,.. . , ;. u r.: - � � . State Stormwater Management Systems Permit No. SW8 040346 Mod. Certification Requirements: '4'1. 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. N LP_4. All roof drains are located such that the runoff is directed into the system. %3�� 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. VL-9. Vegetated slopes are no steeper than 3:1. A2 Y0. The inlets are located per the approved plans and do not cause short-circuiting of the 7 system. 1. The permitted amounts of surface area and/or volume have been provided. �. Required drawdown devices are correctly sized per the approved plans. �. All required design depths are provided. t4. All required parts of the system are provided, such as a vegetated shelf, and a forebay. t5. The required system dimensions are provided per the approved plans. cc: NCDENR-DWQ, Wilmington Regional Office NCDENR-DWQ, Construction Grants and Loans Section, Attn: Ken Pohlig, P.E. Onslow County Building Inspections Page 2 of 2 P\SWAN 974' 61 WLEnWnw S,wmwuu Cmfiiwion Gamma 1,2,3 & 4(12-15-M)) d