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HomeMy WebLinkAboutSW8990413_Historical File_19990819State of North Carolina • Department of Environment and Natural Resources Wilmington Regional Office James B. Hunt, Jr., Governor Wayne McDevitt, Secretary Division of Water Quality Mr. Joe Hearne, Vice -President Clementree, Inc. PO Box 22 Kure Beach, NC 28449. Dear Mr. Hearne: NPA NCDENR NORTH CAROLINA DEPARTMENT OF ENVIRONMENT AND NATURAL REsouROEs August 19, 1999 Subject: Permit No. SW8 990413 Kure Estates, Phase III High Density Subdivision Stormwater Project - New Hanover County The Wilmington Regional Office received a complete Stormwater Management Permit Application for Kure Estates, Phase III on July 8, 1999. 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. SW8 990413, dated August 19, 1999, for the construction of the project, Kure Estates, Phase III. This permit shall be effective from the date of issuance until August 19, 2009, 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 need additional information concerning this matter, please contact Scott Vinson, or me at (910) 395-3900. RSS/:sav cc: Sincerely, Rick Shiver Water Quality Regional Supervisor S:1WQSISTORivIWAT1PERMIT1990413.AUG Phil Tripp, P.E. Tony Roberts, Ncw Hanover County Inspections Beth Easley, New Hanover County Engineering Scott Vinson Wilmington Regional Office Central Files 127 Cardinal Dr. Ext., Wilmington, North Carolina 28405 Telephone 910-395-3900 FAX 910-350-2004 An Equal Opportunity Affirmative Action Employer 50% recycled/10% post -consumer paper State Stormwater Management Systems Permit No. SW8 990413 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 1.43, General Statutes of North Carolina as amended, and other applicable Laws, Rules, and Regulations PERMISSION IS HEREBY GRANTED TO Clementree, Inc. Kure Estates, Phase III New Hanover County FOR THE construction, operation and maintenance of a wet detention pond in compliance with the provisions of 15A NCAC 211.1000 (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 August 19, 2009 and shall be subject to the following specified conditions and limitation' I. DESIGN STANDARDS 1. This permit is effective only with respect to the nature and volume of stormwater described in the application and other supporting data. 2. This stormwater system has been approved for the management of stormwater runoff as described on page 3 of this permit, the Project Data Sheet. The subdivision is permitted for 44 lots, each allowed 3,000 square feet of built -upon area. 3. Approved plans and specifications for this proj ect are incorporated by reference and are er_forceable parts of the permit. 2 State Stormwater'Management Systems Permit No. SW8 990413 Project Name: Permit Number: Location: Applicant: Mailing Address: Application Date: Name of Receiving Stream / Index #: Classification of Water Body: If Class SA, chloride sampling results: Design Storm: Pond Depth, feet: Permanent Pool Elevation, FMSL: Total Impervious Surfaces, ft2: 44lots at3,000 ft2: Roads/Parking, ft2 Other, ft2 Offsite Area entering Pond, ft2: Required Surface Area, ft2: .r Provided Surface Area, ft2: Required Storage Volume, ft3: Provided Storage Volume, ft3: Temporary Storage Elevation, FMSL: Controlling Orifice: [VISION OF WATER QUALITY PROJECT DATA SHEET Kure Estates, Phase III SW8 990413 New Hanover County Mr. Joe Hearne, Vice -President Clementree, Inc. PO Box 22 Kure Beach, NC 28449 July 8, 1999 UT Cape Fear River / (CPF17 18-(71)) "SC it n/a 1" 7.0 11.3 172,960 132,000 r 40,960 n/a n/a 6,453 8,168 14,497 18,126 . 13.20 1.5"diameter pipe 3 State Stormwater Management Systems Permit No. SW8 990413 II. SCHEDULE OF COMPLIANCE 1. No homeowner/lot owner/developer shall fill in, alter, or pipe any drainage feature (such as swales) shown on the approved plans as part of the stormwater management system without submitting a revision to the permit and receiving approval from the Division. 2. The permittee is responsible for verifying that the proposed built -upon area does not exceed the allowable built -upon area. Once the lot transfer is complete, the built -upon area may not be revised without approval from the Division of Water Quality, and responsibility for meeting the built -upon area limit is transferred to the individual property owner. 3. The following items will require a modification to the permit: a. Any revision to the approved plans, regardless of size. b. Project name change. C. Transfer of ownership. d. Redesign or addition to the approved amount of built -upon area. e. Further subdivision of the project area. f. Filling in, altering, or piping of any vegetative conveyance shown on the approved plan. 4. The Director may determine that other revisions to the proj ect should require a modification to the permit. 5. The Director may notify the permittee when the permitted site does not meet one or more ofthe 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. 6. The stormwater management system shall be constructed in it's entirety, vegetated and operational for its intended use prior to the construction of any built -upon surface except roads. 7. During construction, erosion shall be kept to a minimum and any eroded areas of the system will be repaired immediately. 8. The permittee grants permission to DENR Staff to enter the property for the purposes of inspecting the project for compliance with the conditions of this permit. 9. 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 deigner 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. 10. Decorative spray fountains will not be allowed in the stormwater treatment system. 11. 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. 12. Prior to transfer of ownership, the pond must be inspected by DWQ personnel, and determined to be in compliance with all permit conditions. Records of maintenance activities will be required. 4 State Stormwater Management Systems Permit No. SW8 990413 13. 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 side slopes. d. Immediate repair of eroded areas. e. Maintenance of side slopes in accordance with approved plans and specifications. f. Debris removal and unclogging of outlet structure, orifice device and catch basins and piping. g. Access to the outlet structure must be available at all times. 14. 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. 15. Prior to the sale of any lot, deed restrictions must be recorded which limit the built -upon area per lot to the amount as shown on the Project Data Sheet, per Section I, Part 2. The recorded statements must follow the form: a. "The maximum built -upon area per lot is 3,000 square feet. This allotted amount includes any built -upon area constructed within the lot property boundaries, and that portion of the right-of-way between the front lot line and the edge of the pavement. Built upon area includes, but is not limited to, structures, asphalt, concrete, gravel, brick, stone, slate, and coquina, but does not include raised, open wood decking, or the water surface of swimming pools." b. "The covenants pertaining to stormwater regulations may not be changed or deleted without concurrence of the State." C. "Alteration of the drainage as shown on the approved plan may not take place without the concurrence of the State." d. "Lots within CAMA's Area of Environmental Concern may be subject to a reduction in their allowable built -upon area due to CAMA regulations." "All runoff on the lot must drain into the permitted system. This may be accomplished through providing roof drain gutters which drain to the street, grading the lot to drain towaid the street, or grading perimeter swales and. directing them into the pond or street. Lots that naturally drain into the system are not required to provide these measures." 16. 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 bear the signature of the Permittee, the deed book number and page, and stamp/signature of the Register of Deeds. 17. 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. 18. 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. 41 State Stormwater Management Systems Permit No. SW8 990413 III. GENERAL CONDITIONS 1. This permit is not transferable. In the event there is a desire for the facilities to change ownership, or there is a name change of the Permittee, a "Name/Ownership Change Form" must be submitted to the Division of Water Quality accompanied by appropriate documentation from the parties involved, such as a copy of the deed of trust. Other supporting materials, such as a signed Operation and Maintenance plan in the case of engineered systems, will also be required. The project must be in good standing with DWQ. The approval of this request will be considered on its merits and may or may not be approved. 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) which have 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 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. 6. Permittee grants permission to staff of the DWQ to access the property for the purposes of inspecting the stormwater facilities during normal business hours. Permit issued this the 19th day of August, 1999. NORTH CAROLINA ENVIRONMENTAL MANAGEMENT COMMISSION C .(,-- , , �— Kerr T. Stevens, Director Division of Water Quality By Authority of the Environmental Management Commission Permit Number SW8 990413 0 State Stormwater Management Systems Permit No. SW8 990413 Kure Estates, Phase III Stormwater Permit No. SW8 990413 New Hanover County Designer's Certification Page 1 of 2 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, ect) for (Project Owner) hereby state that, to the best of my abilities, due care and diligence was used in the observation of the.proj ect 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 are a part of this Certification. Noted deviations from approved plans and specifications: Signature Registration Number Date SEAL 7 State - Stormwater Management Systems Permit No. SW8 990413 Certification Requirements: Page 2 of 2 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. The outlet/bypass structure elevations are per the approved plan. 5. The outlet structure is located per the approved plans. 6. Trash rack is provided on the outlet/bypass structure. 7. - All slopes are grassed with permanent vegetation. 8. Vegetated slopes are no steeper than 3:1. 9. The inlets are located per the approved plans and do not cause short-circuiting of the system. 10. The permitted amounts of surface area and/or volume have been provided. 11. Required drawdown devices are correctly sized per the approved plans. 12. All required design depths are provided. 13. All required parts of the system are provided, such as a vegetated shelf, a forebay, and the vegetated filter. _14. The overall dimensions of the system, as shown on the approved plans, are provided. cc: NCDENR-DWQ Regional Office Tony Roberts, New Hanover County Building Inspector It V005 g Date Received Fee Paid Permit Number State of North Carolina Department of Environment and Natural Resources Division of Water Quality STORMWATER MANAGEMENT PERIVIIT 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): Clementree, Inc. 2. Print Owner/Signing Official's name and title (the person who is legally responsible for the facility and its compliance): Joe Hearne Vice -President 3. Mailing Address for person listed in item 2 above: P.O. Box 22 City: Kure Beach State: NC Zip: 28449 Telephone Number: (910) 458-4046 4. Project Name (subdivision, facility, or establishment name — should be consistent with project name on plans, specifications, letters, operation and maintenance agreements, etc.): Kure Estates Phase III 5. Location of Facility (street address): Kure Village Way City: Kure Beach County: New Hanover 6. Directions to facility (from nearest major intersection): Approx. 36501f south from the intersection of US Hwy 421 and SR 1539 toward Ft. Fisher to Kure Village Way to project entrance 7. Latitude: N 34' 00' 30" Longitude: W 77' 54' 00" of facility 8. Contact person who can answer questions about the facility: Name: Phillip Tripp Telephone Number: J(910) 763-5100 H. PERMIT INFORMATION: 1. Specify whether project is (check one): X New Renewal Modification 2. If this application is being submitted as the result of a renewal or modification to an existing permiL, list The existing permit number and its issue date (if known) Form SWU-101 April 1998 Page 1 of 4 3. Specify the type of project (check one): Low Density X High Density Redevelop General Permit Other 4. Additional Project Requirements (check applicable blanks): CAMA Major X Sedimentation/Erosion Control 404 Permit III. PROJECT INFORMATION L 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 detention pond 2. Stormwater runoff from this project drains to the Ca OL a" River basin. 3. Total Project Area: 8.4 acres 4. Project Built Upon Area: 41. *2;� %. 5. How many drainage basins does the project have? 1 6. Complete the following information for each drainage basin. If there are more than two drainage basins in the project, attach an additional sheet with the information for each basin provided in the same format as below. Receiving Stream Name a b. (,�t iutr R ,eceiving Stream Class cc Drainage Basin Area 365,904 sf Existing Impervious * Area 0 Proposed Impervious * Area 74 %P0 % Impervious* Area (total) hel , $ On -site Buildings 44 1 b 5 2 1 000 s On -site Streets 0 0 On -site Parkin 0 On -site Sidewalks 0 Other on -site 0 Oil site 0 Total: E= 1-12 6704 E= * Impervious area is defined as the built upon area including, but not limited to, buildings, roads, parking areas sidewalks, gravel areas, etc. How was the off -site impervious area listed above derived? N/A IV. DEED RESTRICTIONS AND PROTECTIVE COVENANTS Deed restrictions and protective covenants are required to he recorded for all low density projects and all subdivisions prior to the sale of any lot. Please see Attachment A for the specific items that must be recorded. Form SAT-101 April 1998 page 2 of 4 By your signature below, you certify that the recorded deed restrictions and protective covenants for this project shall include all the items required by the permit, 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. AGENT AUTHORIZATION If you wish to designate submittal authority to another individual or firm so that they may provide information on your behalf, please complete this section: Designated agent (individual or firm): Tripp Engineering, P.C. Mailing Address: 419 Chestnut Street City: W' n State: NC Zip: 28401 Phone:__(0 763-5100 Fax: (910) 763-5631 VII. SUBMITTAL REQUIREMENTS This application package will not be accepted by the Division of Water Quality unless all of the applicable items are included with the submittal. Please indicate that you have provided the following required information by signing your initials in the space provided next to each item. Auulkant's Initials • Original and one copy of the Stormwater Management Permit Application Form r • One copy of the applicable Supplement Form(s) for each BMP (see Attachment A) PJ • Permit application processing fee (see Attachment A) • 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 and date - Mean high water line - Dimensioned property/project boundary - Location map with named streets or NCSR numbers - Original contours, proposed contours, spot elevations - Details of roads, parking, cul-de-sacs, sidewalks, and curb and gutter Wetlands delineated, or a note on plans that none exist Existing drainage (including off -site), drainage easements, pipe sizes, runoff calculations Drainage basins delineated Vegetated buffers (where required) VI. APPLICANT'S CERTIFICATION I, (print or type name of person listed in General Information, item 2) Joe Hearne certify that the information included on this permit application form is correct, that the proj ect will be constructed in conformance with the approved plans, that the deed restrictions in accordance with Attachment A of this form will be recorded with all required permit conditions, and that to the best of my knowledge, the proposed project complies with the requirements of 15A NCAC 2H .1000. Signature: Title: Form SWLT-101 April 1998 Page 3 of 4 Dater ATTACHMENT A 1. Deed Restriction Language The following statement must be recorded for all low density projects and for all projects that involve the subdivision and selling of lots or outparcels: 1. No more than 3LQW square feet of any lot, including that portion of the right-of-way between the edge of pavement and the front lot line, shall be covered by impervious structures including asphalt, gravel, concrete, brick, stone, slate or similar material but not including wood decking or the surface of swimming pools. This covenant is intended to insure continued compliance with the stormwater permit issued by the State of North Carolina. The covenant may not be changed or deleted without the consent of the State. 2. No one may fill in, pipe, or alter any roadside Swale except as necessary to provide a minimum driveway crossing. NOTE: If lot sizes vary significantly, the owner/developer must provide an attachment listing each lot number, size and the allowable built upon area for each lot. For commercial projects that have outparcels or future development, the following statements must also be recorded: 3. The connection from the outparcel or future area into the stormwater system must be made into the forebay such that short-circuiting of the system does not occur. 4. All built -upon area from the outparcel or future development must be directed into the permitted stormwater control system. 5. Built -upon area in excess of the permitted amount will require a permit modification prior to construction. For curb outlet systems, the following statement in addition to items 1 and 2 above must be recorded: 6. No one may pipe, fill in or alter any designated 100 foot long grassed Swale used to meet the requirements ofNCAC 2H.1008(g). 2. Supplement Forms The applicable supplement form(s) listed below must be submitted for each BMP specified for this project: 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 Nutrient Management Strategy Supplement 3. Permit Application Fees (check made payable to NCDENR and submitted to the appropriate Regional Office) Type of Permit Low Density High Density Other Director's Certification General Permit New, Modification, or Late Renewal $225 $385 $225 $350 $ 50 Form SIVIJ-101 April 1998 Page 4 of 4 Timely Renewal Without Modification n/a $225 n/a n/a n/a Permit No. WS (to be provided by DWQ) State of North Carolina Department of Environment and Natural Resources Division of Water Quality STORM HATER MANAGEMENT PERMIT APPLICATION FORM WET DETENTION BASIN SUPPLEMENT This form may be photocopied for use as an original DWO Stormwater Management Plan Review: A complete stormwater management plan submittal includes a wet detention basin supplement for each basin, design calculations, plans and specifications showing all basin and outlet structure details, and a signed and notarized operation and maintenance agreement. I. PROJECT INFORMATION (please complete the following information): Project Name: Kure Estates Phase III Contact Person: ___Phillip Tripp_Phone Number: ( 910 ) 7635100 For projects with multiple basins, specify which basin this worksheet applies to: Basin Bottom Elevation 4.3 ft. Permanent Pool Elevation 11.3 ft. Temporary Pool Elevation 13.2 ft. Permanent Pool Surface Area 8.168_ sq.ft. Drainage Area _365,904 sq.ft. Impervious Area 3.97 ac. Permanent Pool Volume 31.540_ cu.ft. Temporary Pool Volume 18,126_ cu.ft. Forebay Volume 6,370 cu.ft. SA/DAI used 0.019 Diameter of Orifice 1.5 in. Design TSS Removal 90 % U. REQUIRED ITEMS CHECKLIST (average elevation of the 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) (combined volume of main basin and forebay) (volume detained above the permanent pool) (surface area to drainage area ratio) (85% TSS removal required, see item k below) The following checklist outlines design requirements per the Stormwater Best Management Practices manual (1V.C. Department of Environment, Health and Natural Resources, November 1995) and Administrative Code Section: 15 A 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. Form SWU-102 Rev 1/August 1998 Page 1 of 3 Applits Initials a. The temporary pool controls runoff from the 1 inch storm event. b. The basin length to width ratio is greater than 3: 1. c. The basin side slopes above the permanent pool are no steeper than 3:1. d. A submerged and vegetated perimeter shelf at less than 6:1 is provided (show detail). e. Vegetation above the permanent pool elevation is specified. f. An emergency drain is provided to empty the basin. g. The permanent pool depth is between 3 and 6 feet (required minimum of 3 feet). h. The temporary pool draws down in 2 to 5 days. i. A trash rack is provided for both the overflow and orifice. The forebay volume is approximately equal to 20% of the total basin volume. Sediment storage is provided in the permanent pool. A 30-foot vegetative filter is provided at the outlet2 (include erosive flow calculations). Recorded drainage easement for each basin including access to nearest right-of-way. A site specific operation and maintenance (O & M) plan is provided. o. A vegetation management/mowing schedule is provided in the O & M plan. p. Semi-annual inspections are specified in the O & M plan. q. A debris check to be performed after every storm event is specified in the O & M plan. r. Specific clean -out benchmarks are specified in the O & M plan (elevation or depth). s. A legally responsible party is designated in the O & M plan3 (include name and title). t. If the basin is used for sediment and erosion control during construction, clean out of the basin is specified to be performed prior to use as a wet detention basin. Footnotes: 1 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 non- standard table entries. 2 The requirement for a vegetative filter may be waived if the wet detention basin is designed to meet 90% TSS removal. 3 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. M. WET DETENTION BASIN OPERATION AND MAINTENANCE AGREEMENT The wet detention system is defined as the wet detention basin, forebay, non-integrated pretreatment Systems (pretreatment other than foreb_a_ys), and the vegetated filter if one is provided. This system (check one) U does idoes not incorporate a vegetated falter. This system (check one) ❑ does ®'does not incorporate non-integrated pretreatment. Maintenance activities shall be performed as follows: 1. After every significant runoff producing rainfall event and at least monthly: Form SWU-102 Rev 1/August 1998 Page 2 of 3 a. Inspect the wet detention system for sediment accumulation, erosion, trash accumulation, grass 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. 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 fianctioning. 4. Remove accumulated sediment from the wet detention basin system semi-annually or when depth is reduced to 75% of the original design depth. Removed sediment shall be disposed of in an appropriate manner and shall not be handled in a manner that will adversely impact water quality (i.e. stockpiling near a wet detention basin or stream, etc.) The original design depth is: 7' The sediment removal benchmark depth is: 5.25' 5. Remove cattails and other indigenous wetland plants when they cover 75% of the basin surface. These plants shall be encouraged top grow along the basin perimeter. 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 possible. 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 above maintenance procedures. I agree to notify DWQ of any problems with the system or changes in the name of the project, responsible party, or address. Print name: Clementree Inc. Joe Hearne Address: P.O. Box 22, Kure Beach, NC 28449 Phone: 910-458-4046 Title: Signature: Date: I, Monica V. Loughi a Notary Public for the State of North Carolina County of New Hanover , do hereby certify that _Joe Hearne personally appeared before me this 15+*k day of A ril 19 99 , and acknowledge the due execution of the forgoing system maintenanc�e��}��nts. Witness my hand and official seal, My commission expires Form SW-102 Rev 1/August 1998 Page 3 of 3 TRIPP ENGINEERING, P.C. 41 419 Chestnut Street Wilmington, North Carolina 28401 Phone: (910) 763-5100 - FAX: (910) 763-5631 July 7, 1999 NCDENR Division of Environmental Management Water Quality Section 127 Cardinal Drive Wilmington, NC 28405-3845 Attn: Mr. Scott Vinson Re: Kure Estates Phase III TE 98085 Dear Mr. Vinson: RECCMIVED J U L 0 8 ?999 ;�- In response to your correspondence dated June 28, 1999 we offer the following: 1. We have shown a 5' drainage easement around the pond. 2. A drainage area to the pond has now been delineated. 3. We have included a note stating all roof drains to be directed to the pond. 4. We have provided a swale on the back of the referenced lots to route drainage to the pond. 5. These are existing catch basins. The lots that back up to these catch basins will be graded to drain to the front. 6. Thank you for your correction. The classification is "SC". Please contact us with questions, or if you require any additional information. Thank you. Sincerely, Tripp Engineering, P.C. JU6, • Charles D. Cazier, E.I. CDC:dcb Department of Environment and Natural Resources Wilmington Regional Office James B. Hunt, Jr., Governor Wayne McDevitt, Secretary Division of Water Quality June 28, 1999 Mr. Phil Tripp Tripp Engineering 419 Chestnut Street Wilmington, NC 28401 TIC '�w 1.9AWA 6i 19 NCDENii NORTH CAROUKA DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES Subject: ACKNOWLEDGEMENT OF RECEIPT AND REQUEST FOR ADDITIONAL INFORMATION Stormwater Project No. SW8 990413 Kure Estates Phase III New Hanover County Dear Mr: Tripp: The Wilmington Regional Office received a Stormwater Management Permit Application for Kure Estates Phase III on April 15, 1999. A preliminary review of that information has determined that the application is not complete. The following information is needed to continue the stormwater review: 1. Please locate the pond in a recorded drainage easement. 2. Please delineate the drainage area to the pond. 3. How does the runoff from the back of the lots get into the pond for treatment? 4. How is the runoff from lots 45-52 making its way into the pond to be treated before leaving the site? 5. There is a 36" CUT running along the back of the lots along the western property line. There looks to be three catch basins, one each in lots 61, 63, and 68, entering into the 36" pipe. Please verify as to what these objects are and there purpose. 6. Please re -verify the water body classification submitted. SA was given as the classification to the unnamed tributary to the Cape Fear River that this site drains to, however SC may be more like the correct classification though I may be wrong. Let me know as to the re - verification. 127 Cardinal Dr. Ext., Wilmington, North Carolina 28405 Telephone 910-395-3900 FAX 910-350-2004 An Equal Opportunity Affirmative Action Employer 50% recycled/10% post -consumer paper Mr. Tripp June 28, 1999 Stormwater Project No. SW8 990413 Please note that this request for additional information is in response to a preliminary review. The requested information should be received by this Office prior to July 28, 1999, or the application will be returned as incomplete. The return of a project will necessitate resubmittal of all required items, including the application fee. The Division is allowed 90 days from the receipt of a completed application to issue the permit. If you have any questions concerning this matter please feel free to call me at (910) 395-3900. Sincerely, Scott A. Vinson Environmental Engineer RSS/sav: S:\WQS\STORMWAT\ADDINFO\990413.JUN cc: Wilmington Regional Office Mr. Joe Hearne, VP- Clementree, Inc. April 15, 1999 TRIPP ENGINEERING, P.C. 419 Chestnut Street Wilmington, North Carolina 28401 Phone: (910) 763-5100 • FAX: (910) 763-5631 N� NCDENR Division of Environmental Management Water Quality Section 127 Cardinal Drive Wilmington, NC 28405-3845 Attn: Ms. Linda Lewis Re: Kure Estates Phase III New Hanover County, NC TE 98085 Dear Linda: 1 5 1IS99 Enclosed please find two (2) sets of plans, one (1) signed original and one (1) copy of the application form, one (1) wet detention basin supplement, two (2) sets of sealed calculations and one check for the application fee. Please review for approval and contact us with any questions or comments. Thank you. Sincerely, Tripp Engineering, P.C. a - 44 Phillip G. Tripp, P.E. IDGT:dcb Enc. APR 1 5 1999 BY: Stormwater Narrative April 15, 1999 Re: Kure Estates Phase III New Hanover County TE 98085 The total drainage area of this subdivision is 8.4 acres. The 8.4 acres is subdivided into 44 lots. Each lot may obtain a built upon area of three thousand square feet. An asphalt paved area of 40,960 sgft will also be constructed within the total area. Construction of these impervious surfaces provides a total built upon area of 47.3%. Stormwater will be handled by wet detention sized to meet the state design criteria. 4114/99 PGT Total Drains a Area s . ft. acres 365,904 8.40 Impervious Area Land Use sq. ft. acres 44 lots Q 3000 SF each 132,000 3.03 arkin /as haft 40,960 0.94 concrete 0 0.00 [Total[Iotal 172,960 3.97 Stormwater calculations: Time of Concentration: Hydraulic Length (L) = 400 ft. change in Height (H) = 2 ft. Tc = (L3 /H).se5 / 128 6.06 min. Flow for 2 year, 6 hour Storm (Q2): QPRE _ (CPRE] x (12) x (Area) = 12.35 cfs QPos-r = (CPosT) x (12) x (Area) 29.14 cfs sou 78 P = 3.30 in. for 2 yr, 6 hr storm S = 1000/CN - 10 2.82 Depth (D)= [P-(0.2)(S)f / [P+(0.8)(S)] 1.35 in. Time to Peak Flow: TP = [(43.5)(D)(Area)] / Qs,Pcsr 16.89 min. Detention Pond Desian: Pond Size: Elevation ft.) Surface Area (sq. ft. Normal Pool 11.30 8,168 Flood Pool 13.20 10,912 Top of Bank 15.00 13,365 Bottom of Pool 4.30 1,985 Provided Storage Volume: Vol. _ [(Normal pool SA + Flood Pool SA) / 2] x (F.P. elev. - N.P. elev.) - 18,126 cu. ft. 98085POND.xis KURE ESTATES PHASE III Stormwater Calculations Oft 1 of 2 RECEIVED' APR 15 1999 BY:9Qo41/s % impervious = 0.473 l = 47.3% --- --I say 49.0% CPRE = 0.25 CPosT = (% imp.)(.95)+(1-% imp.)(.25) 0.59 IZ = 5.88 in/hr 110 = 7.23 in/hr Flow for 10 year, 6 hour Storm (Q10): QPRE _ (CPRE) x (110) x (Area) 15.18 cis QPOST = (CPOsr) x (110) x (Area) 35.83 cis Sou storage capacity Tor iu year storm: CN = (98)(% imp.) + (60)(1-% imp.) 78 P = 4.80 in. for 10 yr, 6 hr storm S = 1000/CN - 10 2.82 Depth (D)= [P-(0.2)(S)]2 / [P+(0.8)(S)] 2.54 in. Time to Peak Flow: TP = [(43.5)(D)(Area)] / Q10.P0.5T 25.93 min. State Surface Area Requirement at normalpool: Pond side slopes = 3 :1 Depth below N.P. = 7 ft. SA/DA = 0.0190 (Chart for 90% TSS Removal for Wet Detention Pond without Vegetative Filter Required SA = (SAIDA) x (Total Drainage Area) = 6,952 s . ft. State Volume Required for Storaae of first 1" of runoff, Vol._ [(1/12) x (DA) x (% imp.)] + [(1/12) x (DA) x (1-% imp.) x C] C = 0.2 = 17,629 cu. ft. 98085 4114/99 KURE ESTATES PHASE III 98085 PGT Stormwater Calculations Forebav: Required Volume Vol. = 20% of Permenant Pond Volume 6,308 cu. ft. Outlet Structure Design: Flow for 2-day drawdown: for 1st 1" of stormwater, Q = Provided Vol. / 172,800 sec. (2-days) 0.105 cfs Required Area of Pipe for 2-day drawdown: A= Q/ [Cd x SQRT(2 x g x h)] Cd = 0.6 g = 32.2 ft./sZ h = (F.P. elev.- N.P. elev.) /2 0.95 it. A = 0.0224 sq. ft. Diameter of Pipe for 2-day drawdown: DIA. = SQRT[(A x 4) / pi] = 0.1687 ft. = 2.02 in. Outlet Structure Check: Using a 6 x 6' Basin, Perimeter L = 36 ft. Q = CIA C = (% imp.)(.95) + (1-% imp.)(.25) 0.59 1 = 7.23 in. for a 10 yr. Storm A = 8.40 Acres 35.83 cfs Q= Cwxl.xH'-5 H = [Q / (Cw x L)]213 Cw = 3 0.48 ft. Peak elevation = flood pool elevation + H = 13.68 ft. Provided Volume Normal Pool SA = 2,962 sq. ft. Bottom Pool SA = 1,285 sq. ft. Vol. _ [(N.P. SA + B.P. SA) / 21 x (N.P. el. - B.P. el.) 6,371 cu. ft. depth = 3 ft. Fiow for 5-day drawdown: for 1st 1" of stormwater, Q = Provided Vol. 1432,000 sec. (5-days) = 0.042 cis Required Area of Pipe for 5-day drawdown: A= Q/ [Cd x SQRT(2 x g x h)] Cd = 0.6 g = 32.2 ft./sZ h = (F.P. elev. - N.P. elev.) / 2 0.95 ft. A = 0.0089 sq. ft. Diameter of Pipe for 5-day drawdown: DIA. = SQRT[(A x 4) / pi] 0.1067 ft. 1.28 in. 98085POND.xis 2 of 2