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HomeMy WebLinkAboutSW8031012_COMPLIANCE_20041108STORMWATER DIVISION CODING SHEET POST -CONSTRUCTION PERMITS PERMIT NO. SW 20�ZMb__ DOC TYPE ❑CURRENT PERMIT ❑ APPROVED PLANS ❑ HISTORICAL FILE FCOMPLIANCE EVALUATION INSPECTION DOC DATE =qZL44LS3' YYYYMMDD JOHN L. PIERCE & ASSOCIATES, P.A. LAND SURVEYING • LAND PLANNING • MAPPING OFFICE 910-346-9800 FAX 910-346-1210 E-MAIL bettybllp@blzec rrcom PO Box 1685 or bjarman @ blzec rr com Jacksonville, NC 28541 November 4, 2004 NOV 0 8 2444 Ms Rhonda Hall, Environmental Engineer N C Department of Environment and Natural Resources Division of Water Quality 127 Cardinal Drive Wilmington, NC 28405 Re Aloha Mini Storage --- Stormwater Project No SW8 031012 Dear Ms Hall 409 Johnson Blvd Jacksonville, NC 28540 Please find enclosed two (2) aerial photography maps concerning the above referenced project These maps were flown in 1985 and 1977 as highlighted on the maps As you can see, the acnal maps clearly show the existing Lance building as of the dates listed above Please review these maps and give me a call should you have any questions or feel if more information is needed Sincerely, John L Pierce JOHN L PIERCE & ASSOCIATES P A Jp/bb Encl LOTS FARMLAND AND WOODLAND SURVEYING • SITE PLANNING • SUBDIVISION LAYOUT • LAND DEVELOPMENT PLANNING CONSTRUCTION SURVEYING • TOPOGRAPHIC SURVEYING AND MAPPING Phase I Environmental Audit / Risk Assessment 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 October 28, 2004 Mr Jefferson Michael Drum, Owner Aloha Mini Storage 1203 Castle Drive Jacksonville, NC 28546 Subject REQUEST FOR ADDITIONAL INFORMATION Stormwater Project No SW8 031012 Aloha Mini Storage Onslow County Dear Mr Drum On May 3, 2004, The Wilmington Regional Office requested additional information needed to continue the stormwater review of the Stormwater Management Permit Application for Aloha Mini Storage This request was made by way of a fax sent to Mr John Pierce, John L Pierce & Associates P A who is list as a designated agent on your permit application I have attached a copy of this fax for your reference As of this date, this office has not received any response Therefore, we are assuming that the building in question was constructed after January 1988 and that the runoff from the area associated with this building will have to be treated Please revise your application and supporting documents to account for the additional built upon area associated with this building The requested information should be received by this Office prior to November 29, 2004, 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 North Carolina Division of Water Quality 127 Cardinal Dnve Extension Phone (910) 395-3900 Customer Serwce"77-623-6748 Wilmington Regional office Wilmington, NC 28405-3845 FAX (919) 733-2496 lntemet h2o enr state nc us An Equal Opportunity/Affirmative Action Employer— 50% Recycled110% Post Consumer Paper Nundy neCarolina 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, Rhonda Hall Environmental Engineer RSS/ rbh SIWQSISTORMWATIADDINFO\20041031012 oct04 cc rJohn_P_ierce,_John L -Pierce & Associates_P A Rhonda Hall Wilmington Regional Office Enclosure o f WArFR Michael F Easley, Governor Q William G Ross Jr, Secretary North Carolina Department of Environment and Natural Resources Alan W Klimek P E ,Director Division of Water Quality Coleen h Sullins, Deputy Director Division of Water Quality FAX COVER SHEET Date: May 3, 2004 No of Pages: 1 To: John Pierce From: Laurie Munn Company. John L. Pierce & Assoc. Water Quality Section - Stormwater FAX #: 910-346-1210 FAX # 910-350-2004 Phone # 910-395-3900 DWQ Stormwater Project Number: SW8 031012 Project Name- Aloha Mini Storage MESSAGE - John, 1 received the aerial map that you sent showing that the building was in place in August of 1989 Unfortunately, Mr Drum has to provide treatment for everything done after January of 1988 Unless Mr Drum can prove that the construction was done prior to January 1988 (building permits, receipts of construction), then he will have to treat that area These are the rules established by the Department He may wish to talk to Rick Shiver about his situation if he wants to try to resolve it any other way Let me know how to proceed Do you want me to put this project on hold? Laurie S1WQSISTORMWATIADDINF0120041031012 may04 N C Division of Water Quality 127 Cardinal Drive Extension (910) 395-3900 Wilmington Regional Office Wilmington, NC 28405 (910) 350-2004 Fax Customer Service 1 800 623-7748 ONSLOW COUNTY PUBLIC ACCESS PIN 436909253164 Name DRUM JEFFERSON M & SANDRA J Add r:ss 4606 GUM BRANCH RD SR 1308 Area of Interest ❑ City Boundaries ❑ Fire Districts Index Map (Aerials) Streams Street Center Une Soil Map Flood Data A AE Undefined VE El X ■ X500 Townsttlp Boundary Election Districts Parcel Map This map is prepared for the inventory of real property found within this tunsdiction, and is compiled from recorded deeds, plats, and other public records and data Users of ttus map are hereby rwtdied that the aforementioned public primary rnfomrahon sources should be consulted for venficatron of the information contained on the map The Onslow County, mapping, and software companies assume no legal responsibility for the information contained on this map The data effective date is 101931200410 48 02 AM r i Design Calculations Stormwater Treatment Facilities for Aloha Mini Storage located in Jacksonville, N C 1 PROJECT DESCRIPTION �* ��c,EaKr" t i. e p e e FDd DaQav� t � y 4 ,.Jou.v. WfifTJfirym� n ngi'`e The Project consist of a proposed mini -storage facility located on a 1 58 Ac tract in Jacksonville N C 2 COMPUTE POND AREA REQUIRED a Compute Percent Impervious Impervious Areas On -Site Buildings On -Site Streets On -Site Parking On -Site Sidewalks Other on -site (Dumpsterlgazebo) Off -site Sub Total FUTURE Total Total Area Drainage to Pond Percent Impervious = 0 782 b Compute Pond Surface Area Existing Proposed Total ,, ,19,351 19,351 SF 0 SF 1`, _„ • D�� ��26,152 26,152 SF /0� 0 SF 0 V 0 45,503 45,503 SF 0 62,603 or 782 % 17,100 SF 62,603 SF VV<80,035, SF I. 7 3"t Using Surface Area to Drainage Area Ratio Chan` for 85% TSS Removal (copy attached) and assuming �;k;,'�5 foot pond depth SAIDA = - 5i57�4 % (interpolated) Therefore Surface Area = SA/DA x Drainage Area 4,461 SF say Fl '_4_._4 -8-81 SF J c Compute Minimum Pond Dimensions Assume rectangular shape with 3 1 Length (L) to Width (W) Ratio Length = 116 03 feet Width = 38 68 feet Site conditions, however, dictate Length = ;rs? 132 0 feet so, Width (av+ 344 0 feet Actual LIW = 39 3 DETERMINE VOLUME TO BE CONTROLLED FROM 1" STORM Using Schuler "Simple Method" Rv = 0 05 + 0 009(I) where I = percent impervious Rv = 0 754 in/in Control Volume = Design Rainfall x Rv x Drainage Area Control Volume = 5,029 CF say 5—, 0-4 87 CF 4 DETERMINE REQUIRED STORAGE DEPTH Assume 3 1 side slopes solving for depth (d) by trial & error d = 101 5 DETERMINE ORIFICE SIZE Control Volume must be drawn down over a 2 day - 5 day period Using onfice equation, solve for Diameter (D) that results in 3-112 day penod D = (Q 10 026 (h) 5) s Where Q = (Control Volume 1 3 5 days x 86,400 sec/day) 0 017 cfs h=d12 = 051 Salving for D D = 095 Use �7p:�? 00 " pipe Actual Drawdown with actual drawdown pipe diameter (using onfice equation) Q= 0 018 cfs Draw Down Period = 3 16 days OK, < 5 0 fi SELECT OUTLET STRUCTURE DIAMETER Size outlet structure such that depth of 010 flow <1 0 feet Using Rational Formula (Q=CIA) where Cimper = "0 8 Cpery - Ccum = 07 110 = 6'50 in/hr A = 1 84 ac Q 10 = 7 98 cfs Assuming 1/2 circumference is used as weir and using Francis Formula (Q=3 331-1-1' 6) to solve for L such that H = 10 L = 2 40 Feet Use 24 inch diameter outlet structure 7 DETERMINE Q10 STAGE Q 10 = 7 98 cfs Using Francis Formula (Q=3 331-1-1' 6) solve for H H 10 = 0 83 feet 8 DETERMINE 0100 STAGE (ELEV OF EMERGENCY SPILLWAY) Using Rational Formula (Q=CIA) where Ccum = 067 1100 = i 50- in/hr A = 1 84 ac Q100 = 1043 Using Francis Formula (Q=3 33LH"6) solve for H H 100 = 1 00 feet 9 DETERMINE 0100 STAGE OVER EMERGENCY SPILLWAY (TOP BERM ELEV ) Assume primary spillway blocked (i e , emergency spillway to accommodate 0100) Emergency spillway shall be a broad crested earthem weir designed to pass 100 year storm Using broad crested weir equation H = (QICw x L)?J3 where Q = Q 100 10 43 cfs Cw=30 Length = ,�25 feet H = 0 27 feet 10 FOREBAY SIZING Compute Actual Pond Volumes (using average end method) Avg Incr Incr Cum Main Bay Volume Elevation Area SF Area SF Depth FT Vol (CF) Vogl _CF) Pond Bottom 3500 51 Bottom Veg Shelf 3833 1,260 656 333 2,183 2,183 Normal Pond 4000 3,778 2,519 1 67 4,207 6,390 Main Bay Volume = 6,390 CF Forebay Volume Elevation Area SF Area SF Depth (FT) Vol (CF) Vol (CF) Pond Bottom 3500 14 Normal Pond 4000 710 362 500 1,810 1,810 Forebay Volume = 1,810 CF Total Pond Volume = 8,200 CF Forebay Volume equates to 22 1 % of Total Volume Temp Storage Volume Elevation Area SF Area SF Depth (FT) Vol (CF) Vol (CF) Normal Pond 4000 4,488 Temp Pond Level 4101 6,509 4,999 101 5,048 5,048 Temp Pool Volume = 5,048 CF 11 SUMMARY Pond Elevations Top Berm (minimum) 100-Yr Flood 10-Yr Flood Relative Actual 728 42 28 (say 42 50) H= 0 27 701 42 01 (emerg weir elev) H100 = 1 00 684 41 84 H10= 083 1-inch Storage 601 41 01 (primary weir elev) storage depth = 101 Permanent Pool 500 40 00 (invert out elev) pond depth = 5 Pond Bottom 0 `H 35 00 12 WET DETENTION BASIN SUPPLEMENT Basin Bottom Elevation 3500 Perm Pool Elevation 4000 Temp Pool Elevation 41 01 Perm Pool Surface Area 4,488 SF Drainage Area 1 84 AC Impervious Area 144 AC Perm Pool Volume 8,200 CIF Temp Pool Volume 5,048 CIF Forebay Volume 1,810 CF SAIDA 5 574 Diameter of Orifice 1 00 Design Rainfall 1" Uesign 155 Kemoval 9U%