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HomeMy WebLinkAboutSW8030716_HISTORICAL FILE_20030821STORMWATER DIVISION CODING SHEET POST -CONSTRUCTION PERMITS PERMIT NO. SW �J(i;>07i117 DOC TYPE ❑CURRENT PERMIT ❑ APPROVED PLANS HISTORICAL FILE ❑ COMPLIANCE EVALUATION INSPECTION DOC DATE YYYYMMDD Re: The I,ounders Club Parking Lot Expansion --Subject: Re: The Founders Club Parking Lot Expansion Date: Thu, 21 Aug 2003 10:49:25 -0400 From: "Jeff Petrofl" <jef.petroff@capefearengincering.com> To: "Laurie Munn" <Laurie.Munn cr ncmail.net> Laurie, T just spoke to Mark Brambell with St. James, he really heads up the development portion of that group, and he said that there were no utilites on our project site. There are of course utilities within the ROW of St. James Drive. He said he'd go with us to answer any of those types of questions. He's our contact with St. James and knows the area really well. We can meet at Mark's office, St. James development, which is the very first building on the right after the entrance. Tt would be a convenient meeting spot. Let me know if that's okay. Thanks. Jeff ----- original Message From: Laurie Munn <Laurle.Munn@ncmail.net> To: Jeff Petroff <Jeff.petroff@capefearengineering.com> Sent: Thursday, August 21, 2003 9:37 AM Subject: Re: The Founders Club Parking Lot Expansion > Neff, > Are there any underground utilities on the site? If so, we will need to > get those flagged before the investigation. > Laurie > Iofl 8126I2003 8:20 ArV1 4F. CAPE FEAR Engineering, Inc. September 9, 2003 Laurie Munn NCDENR %Water Quality 127 Cardinal Dr. Ext. Wilmington, NC 28405 RE: The Founders Club Parking Lot Expansion (SW8 030716) Dear Ms. Munn: .Please find the enclosed response to your rcCluest for additional information for the above refcrenccd project. • fwo copies of the first page of both revised Infiltration Basin Supplements showing design calculations for the 25 year-24 hour event. • Two Copies Of the I-CvlsCCl stol'nlwater plan showing a revised Infiltration trench detail and revised grading in the parking lot. 1 trust this information to be sufficient for your review and approval. 1 f you have any questions or require additional information, please contact this office. Thanks for your timely review. Sincerely, RECE' VED SEP 9 9 2003 Jeffrey Petroff, P.E. BY' cc: File Mark Brambell 151 Poole Road, Suite 100 • 6elville, NC 2&451 • TEL: (910) 363-1044 • FAX: (910) 363-1045 www.capefeareng.com ;rhe Founders Cltib Parking Expansion Subject: The Founders Club Parking Expansion Date: Mon, 25 Aug 2003 10:35:00 -0400 From: Laurie Munn <Laurie.Munn@ncmai].net> Organization: DWQ Wilmington Regional Office To: Jeff Petroff <jeff.petroff@capefeareng.com> Jeff, You.are correct. If you can prove that you can store/infiltrate the 25 year-24 hour storm and hold the 1" storm without infiltration, you do not need a bypass. The supplement has to show the design storm as the 25 year-24 hour storm (approximately 811) and the corresponding volume (approximately 3450 cubic feet). So, I need for you to change the front sheet of the supplements and provide calculations for the 8" storm (runoff volume). You can just bring these tomorrow. Also, the calculations show that the infiltration occurs in a swale, but this is the basin, correct? Let me know if this doesn't make sense. It is difficult to communicate in an email sometimes. Everything else looks good. See you at the site at 9:30. Laurie Laurie Munn <Laurle.MLinn @ncmail.net> Environmental Engineer North Carolina Dept of Environmental and Natural Resources NCDWQ Wilmington Regional Office 1 Of 1 8/26/2003 8:23 AM CAPE FEAR Engineering, Inc. August 19, 2003 Laurie Munn NCDENR Water Quality 127 Cardinal Dr. Ext. Wilmington, NC 28405 RE: The Founders Club Parking Lot Expansion (SW8 030716) Dear Ms. Munn: Please find the enclosed response to your request for additional information for the above referenced project. 1. A curb and gutter detail has been added to the plans. 2. The infiltration basin detail has been revised to show a 4" layer of clean sand. 3. In the past, we have been able to permit oversized infiltration systems without a bypass. We were required to show that the system could contain and infiltrate the 25yr-241ir event without any discharge and also show that the system would not flush in the I Oyr-1 Omin event. This design should have been called out on the Infiltration Basin Supplement's checklist and in the narrative, but was not. I'm including a revised initialed checklist and narrative to clear up this oversight. 4. A vegetated swale detail is on the plans. 5. We are available to meet whenever your schedule allows. trust this information to be sufficient for your review and approval. If you have any questions or require additional information, please contact this office. Thanks for your timely review. Sincerely, —4."-.- , ,Ieffrey Petroff, P. . 151 Poole Road, Suite 100 • 8elville, NC 26451 • TEL: (910) 383-1044 • FAX: (910) 383-1045 www.capef6areng.com Michael F. Easley, Governor William G. Ross Jr., Secretary North Carolina Department of Environment and Natural Resources Alan W. Klimek, P.E.,O}rector Division of Water Quabty Coleen H. Sullins, Deputy Director Division of Water Quality August 13, 2003 Mr. John A. Atkinson, Jr. The Founders Club at St. James Plantation, LLC P.O. Box 10879 Southport, NC 28461 Subject: REQUEST FOR ADDITIONAL INFORMATION Stormwater Project No. SW8 030716 The Founders Club Parking Lot Expansion Brunswick County Dear Mr. Atkinson: The Wilmington Regional Office received a Stormwater Management Permit Application for The Founders Club Parking Lot Expansion on July 18, 2003. A preliminary review of that information has determined that the application is not complete. The following information is needed to continue the stormwater review: Please provide a curb and gutter detail on the plans. Please revise the basin detail to show a 4" layer of clean sand on the bottom of the basin. The excess runoff must bypass the device before it enters the basin. I have enclosed some details in my copy to the engineer. 4. Please provide a detail of the vegetative filter. Please contact me to set up a time for Vincent Lewis, State Soils Scientist, to do an on - site investigation. 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 September 13, 2003, or the application will be returned as incomplete. The return of a project will necessitate resubmittal of all required items. including the application fee. If you need additional time to submit the information, please mail or fax your request for a time extension to the Division at the address and fax number at the bottom of this letter. The request must indicate the date by which you expect to submit the required information. The Division is allowed 90 days from the receipt of a completed application to issue the permit. The construction of any impervious surfaces, other than a construction entrance under an approved Sedimentation Erosion Control Plan, is a violation of NCGS 143-215.1 and is subject to enforcement action pursuant to NCGS 143-215.6A. N. C. Division of Wafer Quality 127 Cardinal Drive Extension (910) 395-3900 Wilmington Regional Office Wilmington, NC 28405 (910) 350-2004 Fax Customer Service 1 800 623-7748 Vism I�lCDEhR Mr. John A. Atkinson, Jr. August 13, 2003 Stormwater Project No. SWS 030716 Please reference the State assigned project number on all correspondence. Any original documents that need to be revised have been sent to the engineer or agent. All original documents must be returned or new originals must be provided. Copies are not acceptable. If you have any questions concerning this matter please feel free to call me at (910) 395-3900. Sincerely, Laurie Munn Environmental Engineer RSS/:Ism S:IWQSISTORMWATIADDINFO120031030716.aug03.doc cc: Laurie Munn Jeff Petroff, P.E. The Founders Club Parking Lot Expansion Subject: The Founders Club Parking Lot Expansion Date: Wed, 13 Aug 2003 12:44:36 -0400 From: Laurie Munn <Laurie.Munn@ncmail.net> Organization: DWQ Wilmington Regional Office To: Jeff Petroff<jeff.petroff@capefeareng.com> Jeff, I am reviewing the above project. Our soils scientist Vincent Lewis will need to do a soils investigation. Do you know if he has already been to this site? If not, do you want me to set something up? He will be out of town through next Wednesday, but I can maybe get him on the schedule for the end of next week or the beginning of the week of the 25th. It is not necessary for you to meet us out there, but you are welcome to come. It is helpful when the engineer is there so that you can tell us where the basins are going to be on the site. I don't think that will be an issue on such a small site though. Just let me know. I am going to send some comments out today. Thanks, Laurie Laurie Munn <Laurie.Munn a nemail.net> Environmental Engineer North Carolina Dept of Environmental and Natural Resources NCDWQ Wilmington Regional Office 1 of 1 8/13/2003 12:44 PM V� � CAPE FEAR Engineering, Inc. 151 Poore Road, suit© 100 Relvillo, NC 28451 TEL (910) 383.1044 FAX (910) 383-1045 www.capefeareng.com To: NCDENR —Water Quality 127 Cardinal Dr. Ext. Wilmington, NC 28405 Attn: 0� RECEIVE \ J U L 18 Z003 Transmittal Date: 7/18/03 File: 700-20 Subject: The Founders Club Parking Lot Expansion — St. James Plantation Brunswick County ❑ As Requested ❑ For Your Files ❑ For Distribution ® For your Review 1 Action 1 Approval ❑ Sent via Mail ❑ Sent via Courier Quantity Drawing No. Description 2 Stormwater And Erosion Control Plan 2 Design Narrative with Calculations 2 Original and One Copy of Application 2 Original Supplements 1 $420 Application Fee REMARKS if you have any questions or comments, please contact this office. Thanks. CC: File Mark Brambell Signed Cape Fear Engineering, Inc. TransStormwater.doc M Storm Water / Erosion Control Design Narrative and Calculations Subject: The Founders Club Parking Lot Expansion At St. James Plantation Brunswick County, North Carolina Prepared for The Founders Club at St. James Plantation, LLC P.O. Box 10879 Southport, North Carolina 28461 (910) 253-4739 Date: July, 2003 Revised August, 2003 Prepared by Cape Fear Engineering, Inc. 151 Poole Road, Suite 100 Belville, North Carolina 28451 (910) 383-1044 :4 F DESIGN NARRATIVE 1. GENERAL: The project site is located within St. James Plantation adjacent to the Founders Club in Brunswick County, North Carolina. The project area for the parking lot expansion is approximately 0.92 acres. Drainage considerations are to be in accordance with state storm water requirements. 2. EXISTING SITE: Site topography in the area is relatively flat with slopes typically less than one (1) percent. The vegetation consists primarily of minor ground cover and a thin stand of trees within the area of the improvements. Subsurface soils are typically a mixture of sands, silty sands and organics. 3. PROPOSED IMPROVEMENTS: Improvements proposed include the construction of a 30 space asphalt parking lot. The site will be graded to divert all storm water runoff into two curb cuts draining to the proposed infiltration trenches. The trenches will be roughed in first and will be utilized to collect and contain any sediment during construction from leaving the site. 4. DRAINAGE CALCULATION CONSIDERATIONS: Attached to this design narrative are the drainage calculations determining the amount of storm water to be contained and treated in the two systems. The infiltration trenches are oversized to be able to contain and infiltrate the 25-year, 24-hour storm event. They are also sized to prevent flushing in the 10-year, 10-minute event. With this oversizing, all runoff from impervious surfaces is directed to the treatment devices without a bypass system. 5. EROSION CONTROL CONSIDERATIONS: The proposed infiltration trenches will be used as trapping devices during construction and have sufficient storage for the calculated amount of disturbance. Also, the lower slope perimeter will be enclosed in silt fence as shown on the plan for added protection. The area of disturbance is limited to within the project area. 6. MAINTENANCE CONSIDERATIONS: During construction, the Contractor shall be required to inspect and repair as needed all erosion control devices after any significant rain event. Any measure found not performing its intended function, shall be repaired immediately. Upon completion of construction the establishment of Storm water 1 Erosion Control Design Narrative and Calculations Subject: The Founders Club Parking Lot Expansion At St. James Plantation Brunswick County, North Carolina Prepared for The Founders Club at St. James Plantation, LLC P.O. Box 10879 Southport, North Carolina 28461 (910)253-4739 � N C A v ,' Q 9y SEAS. � Date: July, 2003 _ 028858 1 Prepared by Cape Fear Engineering, Inc. 151 Poole Road, Suite 100 Belville, North Carolina 28451 (910)383-1044 DESIGN NARRATIVE 1. GENERAL: The project site is located within St. James Plantation adjacent to the Founders Club in Brunswick County, North Carolina. The project area for the parking lot expansion is approximately 0.92 acres. Drainage considerations are to be in accordance with state storm water requirements. 2. EXISTING SITE: Site topography in the area is relatively flat with slopes typically less than one (1) percent. The vegetation consists primarily of minor ground cover and a thin stand of trees within the area of the improvements. Subsurface soils are typically a mixture of sands, silty sands and organics. 3. PROPOSED IMPROVEMENTS: Improvements proposed include the construction of a 30 space asphalt parking lot. The site will be graded to divert all storm water runoff into two curb cuts draining to the proposed infiltration trenches. The trenches will be roughed in first and will be utilized to collect and contain any sediment during construction from leaving the site. 4. DRAINAGE CALCULATION CONSIDERATIONS: Attached to this design narrative are the drainage calculations determining the amount of storm water to be contained and treated in the two systems. S. EROSION CONTROL CONSIDERATIONS: The proposed infiltration trenches will be used as trapping devices during construction and have sufficient storage for the calculated amount of disturbance. Also, the lower slope perimeter will be enclosed in silt fence as shown on the plan for added protection. The area of disturbance is limited to within the project area. G. MAINTENANCE CONSIDERATIONS: During construction, the Contractor shall be required to inspect and repair as needed all erosion control devices after any significant rain event. Any measure found not performing its intended function, shall be repaired immediately. Upon completion of construction the establishment of permanent ground cover will be a priority. Erosion and Sedimentation Control 1.01 General: The contractor shall be responsible for erosion and sedimentation control within the construction limits; for prevention of sediment laden ninoff leaving the construction limits or entering ditches, streams or water impoundments; and for implementation of necessary erosion and sedimentation control measures to meet the requirements of the North Carolina Department of Environment, Health, and Natural Resources. The Contractor shall also be responsible for all damages or fines resulting from erosion or sediment laden runoff in the execution of his contract. 1.02 Construction Sequence: While the use of erosion and sedimentation control devices is especially important on areas of steep topography, easily erodible soils and sites in close proximity to water courses throughout the construction period, the control measures should be installed prior to the commencement of land clearing and shall be frilly maintained and periodically inspected until final restoration and stabilization is completed. Unrestored cleared areas shall be kept to a minimum. Disturbed areas ahead of construction shall only be accomplished on those segments for the shortest practical distance as required for continual progress. Final restoration shall not be delayed until completion of the project but will be carried out in phases as the work proceeds. Under no circumstances will any areas be left denuded for more than (15) fifteen calendar days without some form of stabilization until final restoration is complete. 1.03 Sedimentation: Control Measures: The following are some of the sediment control devices or measures that may be required to prevent sedimentation of streams, water courses, or drainage structures: l . Earth berms and/or diversion and intercept ditches. 2. Sediment traps 3. Filter berms 4. Filter inlets 5. Silt fences - not to be placed in streams or ditches perpendicular to flow. G. Check dams gravel filter 7. Gravel construction exit 1.03.1 Erosion Control Measures: Some of the soil erosion control measures which may be required in this contract are: l . Earth slope protection 2. Diagonal water break diversion berms 3. Diversion channels 4. Preservation of existing vegetation 5. Storm inlet protection G. Stream crossings 7. Energy dissipators & Matting of re -seeded areas 1.03.2 Detail Drawing: Examples of sedimentation and erosion control details are shown in these plans for installation at locations designated in the plans or as otherwise required by the regulating agency, or the owner as work proceeds. 1.04 Stream Protection: Where construction activities are necessary in close proximity to streams, and other waterways, they shall be performed in a manner that does not contribute to degradation of or blockage of the stream -flow. In order to prevent possible degradation or blockages, the contractor shall be required to: 1. Keep all construction debris, excavated materials, brush, rocks, refuse and topsoil as far from these waterways as possible. Restrict machinery operation or stream crossings in waterways to the extent necessary for construction of utilities crossings. 2. If construction work areas are necessary in a waterway, they shall be protected as indicated on the plans. 3. If temporary roadways are essential for the construction activities, they shall be constructed of soils which are not highly erodible materials and must not span more than half way across the water course or wetland area at any one time unless otherwise approved by the Engineer. These temporary roadways shall be entirely removed as soon as their requirement is met. Work in these areas shall follow the requirements of the Corp of Engineers or CAMA permit, or plans as applicable. 1.05 Construction Access: The travel of equipment to and from the construction areas shall be minimized not only to protect areas that will not be denuded, but also to prevent the spreading of sediment within and outside of the construction areas. Therefore, special construction equipment travel corridors will be established for this use and instructions shall be issued for their use. Use of these corridors must be fully enforced. Other non- essential traffic will be restricted or discouraged. Indiscriminate and convenience traffic shall not be allowed. 1.06 Stockpile/Barrow Areas: The Contractor shall be responsible for selecting, obtaining and maintaining stockpile or borrow areas which he may require to complete the contract. He is also required to design and incorporate all necessary sediment and erosion controls measures necessary to prevent erosion and contribution of sediment to adjacent areas. The Contractor is responsible to obtain all necessary permits or approvals for borrow or spoil areas outside the construction limits. 1.07 Disposal of Excess Water from Excavations: The Contractor shall practice management of excess water pumped from excavation to reduce the production and spreading of sediment. Pumped water shall be discharged onto stabilized surfaces and allowed to filter through existing vegetation if possible; otherwise, additional control measures may be necessary. If ditches are required to remove pumped water from construction excavations, they shall be given the same consideration as any other man- 3nade waterway and they shall be stabilized as to not degrade and produce sediment. 1.08 Excavation and Backfill: Fxcavation shall he closely controlled and all the material removed from the excavation shall be selectively stockpiled in areas where a minimum of sediment will be generated and where other damage will not result from the piled material. Drainage ways shall be protected at all times and the placement of material in Drainage ways for convenience shall not be allowed. Backf (ling operations shall be performed in such a manner that remaining trees are not damaged. 1.09 Final Grading and Seeding: Finish grading, topsoiling, seeding and/or sodding shall be perfonned after the constniction phase is complete. Permanent vegetation of the areas, that have been disturbed, shall be re-established as rapidly as possible. If the completion of the construction activities do not coincide with a season in which pen-nanent vegetation can be generated, an interim or temporary program is required. This shall include soil conditioners and mulching as necessary for soil stabilization. In any case, sediment and erosion controls shall be installed promptly and their maintenance assured. 1.10 Approval: The approved Erosion Control Plan will be provided by the Owner. Any standard conditions relating to soil erosion and sediment control issued to the Contractor as a part of any permits shall be available at the job site at all times. End of Section The Founders Club Parking Lot Exapnsion St. James Plantation D15TUR5ED AREA i STORAGE CALCULATIONS Infiltration Trench # I Disturbed Area = 7;8a0x sf Storage Required: 7,800 sf nch Area nch Depth 0.5 0.0833 } 420 sf Al ft e Provided = 420 cf Provided Required 420 > 325 OK Disturbed Area =sf Storage Required: 8,000 sf Trench Area Trench Depth 0.5 0.0833 f3.60E sf ft 325 cf = 333 cf e Provided = 360 cf Provided Required 360 > 333 OK 7/16/03 1 of 1 INFILTRATION SWALE - Schueler Method 7/16/03 inf-swalel .xls 1 of4 4V Engineering, Inc. 151 Poole Road, Swto 100 $clvifle, NC 28451 TEL (910) 383-1044 FAX (910) 383-7045 www.capefeareng.com BASIN DATA l7�ainageArea'Designatian ,skr E� � §"�" �` �mw 5waleDesi nation, SW 11' b Receivingstream class l_. f s.�SC waters Onsite Area = �� �<,; 0"1'8 acres Onsite Impervious Area=;;r0:1:3 x::t;�_�� , acres Offsite Area = 0:00 acres Offsite Impervious Area acres Total Area = 0.18 acres Total Impervious Area = 0.13 acres Percent Impervious = Impervious drainage area (acres)lDrainage area (acres) = 72.2 A) Determine volume to be controlled from storm (1.5 inch event for SA waters, 1 inch event for others) Using the runoff volume calculations per "Simple Method" as described by Schueler (1987): where: Rv = runoff coefficient = storm runoff (inches) / storm rainfall (inches) I = Percent Impervious = Impervious portion of the drainage area (acres) / Drainage area (acres) Rv = 0.05 + 0.009(I) Rv = 0.05 + 0.009 * 72.2 - 0.700 (in/in) Volume to be controlled from the design storm event. - where: Design rainfall = 1.0 (in) Rv = 0.700 (in/in) Drainage Area 0.18 (acres) Volume required (cf) = rainfall (in) x Rv (in/in) x Drainage Area (acre) x 1/12(feetlinches) x 43560 (sflacre) Vreq'd = 1.0 * 0.700 " 0.18 * 1112 * 43560 = 457 cubic feet INFILTRATION SWALE - Schueler Method 7/16/03 inf-swalel .xis 2of4 FEAR VCAPE Engineering, Inc. 151 Poole Road, Suite 100 6elville, NC 28451 TEL (910)383-1044 FAX (910) 383-1045 www.capefeareng.com Determine the volume of the proposed swale: SWALE DATA Cross -sectional Area (A) = bd +HdA2 = 18.00 sf bottom width (b) _ W4151 ft depth (d) = ft sideslope (H:V) :1 length of swale (L) _ ; ft rn^rr EASEMENT - WIflTF? AS INDICATED INFILTRATI[IN SWALE NOT TO SCALE Volume proposed (cf) = Cross -sectional area (sf) x length of swale (ft) Vprop = 18 sf 28 ft = 504 cubic feet lCompare volume proposed to volume required from the design storm event: rap = 504 cf > Vreq'd = 457 cf (OK -proposed swale volume is greater than minimum required volume) INFILTRATION SWALE - Schueler Method 7/16/03 inf-swalel.xls 3of4 4V(CASE FEAR Engineering, Inc. 151 Poole Road, Suite 100 Belvillo, NC 28451 TEL (910) 383-1044 FAX (910) 383-1045 www,capefeareng,com Bj Check swale infiltration rate for capacity to control the 25 year-24 hour storm event with no discharge The average weighted coefficient of runoff is determined by: C ave = Sum[CA ] 1 Sum[A] Description AREA C CA Impervios Area 0.13 0!0 0.124 Pervious Area 0.05 -60 0.008 Sum A = 0.18 Sum CA = 0.131 C ave = 0.131 1 0.18 = 0.728 Determine required discharge from 25 year-24 hour storm event: Q regd = Cave x 1 x A Q regd = 0.73 * 0.33 * 0,18 = 0.04 cfs where: I = intensity for 25 year-24 hour storm event from Chart E-6 = 0.33 inlhr A = drainage area = = 0,18 acres Cave = weighted coefficient of runoff = 0.73 Check available rate of infiltration provided by proposed swale: where: I = infiltration rate of soil (Soil Type = Newhan & Fripp sands) y -:4 '20 inlhr A = bottom area of swale = 15.0 ft * 28 ft = 420 sf Qavail = IA = 20 inlhr * 420 sf * 1 ft112 in * 1 hr13600sec - 0.19 cfs Compare rate of infiltration with runoff rate from the 25 year storm event: Qavail = 0.19 cf > Q regd = 0.04 cf (OK -No Discharge for 25 yr-24 hr storm event) INFILTRATION SWALE - Schuefer Method 7/16/03 inf-swale1.xls 4of4 4V(CAPE FEAR Engineering, Inc. 151 Poole Raad. Suite 100 8elvifle, NC 28451 TEL (910) 383-1044 FAX (910) 383-1045 www.capefearen_q.com C) Check the 10 year-10 minute storm event to confirm that swale has capacity without flushing system where-, I = intensity for 10 year-10 minute storm event from Chart E-6 inlhr A = drainage area = = 0.18 acres Cave = weighted coefficient of runoff = 0.73 Determine discharge rate from 10 year-10 minute storm event: Q 10-yr = Cave x I x A Q 10-yr = 0.73 * 6.3 * 0.18 = 0.83 cfs Determine discharge volume from 10 year-10 minute storm event: V 10-yr = Q 10-yr * 10 min. duration * 60 sec/min. - 495 cf Check available volume of the proposed infiltration swale: V avail = design volume (from swale data table) = 504 cf Compare design volume of infiltration swale to discharge volume from 10 year storm event of 10 minute duration: Vavail = 504 cfs > V 10-yr = 495 cfs. (OK-swale has adequate capacity for 10-yr event without flushing) Compare infiltration system drawdown time to maximum drawdown period of 5 days T = V regd 1 Q avail * 1 hrl 3600 sec T = 457 cf / 0.19 cfs * 1 hr13600 sec - 0.65 hours (OK- system draws down in less than 5 days) INFILTRATION SWALE - Schuefer Method 7/16/03 inr-swale2.xls 1 of4 CARE FEAR '�'r Engineering, Inc. 151 Poole Road, Suite 100 Oelville, Nc 28451 TEL (910) 383-1044 FAX (910) 383-1045 www.capefeareng.com BASIN DATA DralnageAreaDesEgnation: °� �I ,`SRAINAGEAREAff2 SwalDesignation; ._ i } �Y Receiving stream class pSC waters Onsite Area = 01'8 acres Onsite Impervious Area = 0.. acres Offsite Area =` ��.t).00 acres Offsite Impervious Area =�; E0:00 acres Total Area = 0.18 acres Total Impervious Area = 0.12 acres Percent Impervious = Impervious drainage area (acres)IDrainage area (acres) = 66.7 A) Determine volume to be controlled from storm (1.5 inch event for SA waters, 1 inch event for others) Using the runoff volume calculations per "Simple Method" as described by Schueler (1987): where: Rv = runoff coefficient = storm runoff (inches) / storm rainfall (inches) I = Percent Impervious = Impervious portion of the drainage area (acres) 1 Drainage area (acres) Rv = 0.05 + 0.009(I) Rv = 0.05 + 0.009 * 66.7 = 0.650 (in/in) Volume to be controlled from the design storm event: where: Design rainfall Rv Drainage Area 1.0 (in) - 0.650 (in/in) = 0.18 (acres) Volume required (cf) = rainfall (in) x Rv (in/in) x Drainage Area (acre) x 1/12(feet/inches) x 43560 (sflacre) Vreq'd = 1.0 * 0,650 * 0.18 * 1112 * 43560 = 425 cubic feet INFILTRATION SWALE - Schueler Method 7/16/03 inf-swale2.xls 2of4 CARE FEAR Engineering, Inc. 151 Poole Road, Suite 100 Belvilfe, NC 28451 TEL (910) 383-1044 FAX (910) 383-1045 www.capefeareng.com Determine the volume of the proposed swale: SWALE DATA Cross -sectional Area (A) = bd +Hd"2 = 13.00 sf bottom width (b) _ 10.0 ft depth (d) _ 1 ft sideslope (H:V) :1 of swale (L) = il,jlength e `36 ft EASEMENT - 6WDTH .:; INDICATED INFIL,TRATIEI\ SWALE NOT TO SCA! Volume proposed (cf) = Cross -sectional area (so x length of swale (ft) Vprop = 13 sf 36 ft = 468 cubic feet Compare volume proposed to volume required from the design storm event: = 468 cf > Vreq'd = 425 cf (OK -proposed Swale volume is greater than minimum required volume) INFILTRATION SWALE - Schueler Method 7/16/03 inf-swale2.xls 3of4 ,,;�„ , (CAPE FEAR "� ' Engineering, h7c. 151Poole Road, sure Too B©lvilre, NC 29451 T,k {910) 383.1044 FAX f910) 363-1045 www.copefearen_q.com B) Check swale infiltration rate for capacity to control the 25 year-24 hour storm event with no discharge The average weighted coefficient of runoff is determined by: C ave = Sum[CA ] 1 Sum[A] Description AREA C CA Empervios Area 0.12 O's99 0.114 Pervious Area 0.06 0:1'S. 0.009 Sum A = 0.18 Sum CA = 0.123 C ave = 0.123 I 0.18 = 0,683 Determine required discharge from 25 year-24 hour storm event: Q regd = Cave x I x A Q regd = 0.68 * 0.33 * 0.18 where: I = intensity for 25 year-24 hour storm event from Chart E-6 A = drainage area = Cave = weighted coefficient of runoff Check available rate of infiltration provided by proposed swale: where: I = infiltration rate of soil (Soil Type = Newhan & Fripp sands) A = bottom area of swale = 10.0 ft * 36 ft Qavail = IA = 20 inihr 360 sf * 1 ft112 in * 1 hr/3600sec Compare rate of infiltration with runoff rate from the 25 year storm event. Qavail = 0.17 cf > Q regd = 0.04 cf (OK -No Discharge for 25 yr-24 hr storm event) = 0.04 cfs ;0.33 inihr 0.18 acres 0.68 inihr 360 sf 0,17 cfs INFILTRATION SWALE - Schueler Method 7116/03 inf-swale2.xls 4of4 CAPE FEAR " =%; Fngiheeriiqg, Inc. 151 Poole Road, Suite 100 Belvifle, NC 28451 7EC (910) 383-1044 FRX (910) 3R3-1045 www.capereareng.com C) Check the 10 year-10 minute storm event to confirm that swale has capacity without flushing system where: I = intensity for 10 year-10 minute storm event from Chart E-6 = a .'' 6.3 inlhr A = drainage area = = 0.18 acres Cave = weighted coefficient of runoff - 0.68 Determine discharge rate from 10 year 10 minute storm event. Q 10-yr = Cave x I x A Q 10-yr = 0.68 ' 6.3 " 0.18 = 0.77 cfs Determine discharge volume from 10 year-10 minute storm event: V 10-yr = Q 10-yr " 10 min. duration " 60 sec/min. = 465 cf Check available volume of the proposed infiltration swale: V avail = design volume (from swale data table) = 468 cf Compare design volume ofinfiltration swale to discharge volume from 10 yearstorm event of 10 minute duration: Vavail = 468 cfs > V 10-yr = 465 cfs (OK-swale has adequate capacity for 10-yr event without flushing) Compare infiltration system drawdown time to maximum drawdown period of 5 days T= V regd i Q avail 1 hr13600 sec T = 425 cf 1 0.17 cfs 1 hr13600 sec - 0.71 hours (OK- system draws down in less than 5 days) State Stormwater Management Systems Permit No. SW8 030716 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 The Founders Club at St. James Plantation, LLC The Founders Club Parking Lot Expansion Brunswick County FOR THE construction, operation and maintenance of 2 infiltration basins 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 September 15, 2013, and shall be subject to the following specified conditions and limitations: 1. DESIGN STANDARDS This permit is effective only with respect to the nature and volume of stormwater described in the application and other supporting data. 2. This stormwater system has been approved for the management of stormwater runoff as described on page 3 of this permit, the Project Data Sheet. The stormwater control has been designed to handle the runoff from 10,915 square feet of impervious area. The system is not operated with a vegetative filter but is designed for the 25 year — 24 hour storm event. The tract will be limited to the amount of built -upon area indicated on page 3 of this permit, and per approved plans. 4. All stormwater collection and treatment systems must be located in either dedicated common areas or recorded easements. The final plats for the project will be recorded showing all such required easements, in accordance with the approved plans. 5. The runoff from all built -upon area within the permitted drainage area of this project must be directed into the permitted stormwater control system. A permit modification must be submitted and approved prior to the construction of additional built -upon area from outside of the approved drainage area. 0 State Stormwater Management Systems Permit No. SW8 030716 DIVISION OF WATER QUALITY PROJECT DESIGN DATA SHEET Project Name: The Founders Club Parking Lot Expansion Permit Number: SW8 030716 Location: Brunswick County Applicant: The Founders Club at St. James Plantation, LLC Mailing Address: P.O. Box 10879 Southport, NC 28461 Application Date: September 15, 2003 Receiving Stream/River Basin: Polly Gully Creels / Cape Fear Stream Index Number: CPF 17 18-88-9-1-1 Classification of Water Body: "SC" Design Storm 1" Basin Number 1 2 Drainage Area, acres: 0.18 0.18 Total Impervious Surfaces, sq. ft.: 5,600 5,315 Pond Depth, feet: - 1.25 1.25 TSS removal efficiency: 90% 90% Bottom Elevation, FMSL: 7.0 6.0 Bottom Surface Area, sq. ft.: 420 360 Permitted Storage Volume, cubic ft.: 504 468 Temporary Storage Elevation, FMSL: 8.0 7.0 ' Type of Soil: Leon Leon Expected Infiltration Rate, inlhr: 20" 20" Seasonal High Water Table Elev,- FMSL: 4.0 4.0 Expected time to draw down, days: 0.22 0.23 3 State Stormwater Management Systems Permit No. SW8 030716 II. SCHEDULE OF COMPLIANCE 1. The stormwater management system shall be constructed in its entirety, vegetated and operational for its intended use prior to the construction of any built -upon surface. 2. During construction, erosion shall be kept to a minimum and any eroded areas of the system will be repaired immediately. 3. The permittee shall at all times provide the operation and maintenance necessary to assure the permitted stormwater system functions at optimum efficiency. The approved Operation and Maintenance Plan must be followed in its entirety and maintenance must occur at the scheduled intervals including, but not limited to: a. Semiannual scheduled inspections (every 6 months). b. Sediment removal. C. Mowing and revegetation of slopes and the vegetated filter. d. Immediate repair of eroded areas. e. Maintenance of all slopes in accordance with approved plans and specifications. f. Debris removal and unclogging of outlet structure, orifice device, flow spreader, catch basins and piping. g. Access to the outlet structure must be available at all times. 4. Records of maintenance activities must be kept and made available upon request to authorized personnel of DWQ. The records will indicate the date, activity, name of person performing the work and what actions were taken. Decorative spray fountains will not be allowed in the stormwater treatment system. 6. The facilities shall be constructed as shown on the approved plans. This permit shall become voidable unless the facilities are constructed in accordance with the conditions of this permit, the approved plans and specifications, and other supporting data. 7. Upon completion of construction, prior to issuance of a Certificate of Occupancy, and prior to operation of this permitted facility, a certification must be received from an appropriate designer for the system installed certifying that the permitted facility has been installed in accordance with this permit, the approved plans and specifications, and other supporting documentation. Any deviations from the approved plans and specifications must be noted on the Certification. A modification may be required for those deviations. 8. If the stormwater system was used as an Erosion Control device, it must be restored to design condition prior to operation as a stormwater treatment device, and prior to occupancy of the facility. 9. 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, or sale of all or part of the project area. The project area is defined as all property owned by the permitter, 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. 4 State Stormwater Management Systems Permit No. SW8 030716 10. The permittee shall submit final site layout and grading plans for any permitted future areas shown on the approved plans, prior to construction. If the proposed BUA exceeds the amount permitted under this permit, a modification to the permit must be submitted and approved prior to construction. 11. 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. 12. At least 30 days prior to the sale or lease of any portion of the property, the permittee shall notify DWQ and provide the name, mailing address and phone number of the purchaser or leasee. An access/maintenance casement to the stormwater facilities shall be granted in favor of the permittee if access to the stormwater facilities will be restricted by the sale or lease of any portion of the property. 13. The permittee must maintain compliance with the proposed built -upon area and ensure that the runoff from all the built -upon is directed into the permitted system. 14. 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. 15. The permittee must maintain the current permitted drainage area. No additional runoff from outside of the permitted drainage area boundary may enter the permitted stormwater facilities without first applying for and receiving a permit modification. 1111. GENERAL CONDITIONS This permit is not transferable except after notice to and approval by the Director. In the event of a change of owership, or a name change, the permittee must submit a formal permit transfer request to the Division of Water Quality, accompanied by a completed name/ownership change form, documentation from the parties involved, and other supporting materials as may be appropriate. The approval of this request will be considered on its merits and may or may not be approved. The permittee is responsible for compliance with all permit conditions until such time as the Division approves the transfer request. 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 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. State Stormwater Management Systems Permit No. SW8 030716 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. Approved plans and specifications for this project are incorporated by reference and are enforceable parts of the permit. 9. The permittee shall notify the Division any name, ownership or mailing address changes within 30 days. Permit issued this the 15th day of September, 2003. NORTH CAROLINA ENVIRONMENTAL MANAGEMENT COMMISSION Alan W. Klimek,-.E., Director 4� Division of Water Quality By Authority of the Environmental Management Commission State Stormwater Management Systems Permit No. SW8 030716 The Pounders Club Parking Lot Expansion Stormwater Permit No. SW8 030716 Brunswick County Designer's Certification A as a duly registered in the State of North Carolina, having been authorized to observe (periodicallylweekly/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 7 State Stormwater Management Systems Permit No. SW8 030716 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. 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. IL 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, and a forebay. 14. The overall dimensions of the system, as shown on the approved plans, are provided. cc: NCDENR-DWQ Regional Office Brunswick County Building Inspections