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HomeMy WebLinkAboutSW8970305_COMPLIANCE_20070823STORMWATER DIVISION CODING SHEET POST -CONSTRUCTION PERMITS PERMIT NO. SW Gy�,rj DOC TYPE ❑ CURRENT PERMIT ❑ APPROVED PLANS ❑ HISTORICAL FILE COMPLIANCE EVALUATION INSPECTION DOC DATE, YYYYM M D D Michael F. Easley, Governor o�o� W A r�qp� August 23, 2007 Mr. Jon T. Vincent, Owner Gulf Stream Shopping Center 1508 Military Cutoff Road, Suite 302 Wilmington, NC 28403-5730 Subject:: Stormwater Permit No. SW8970305 Gulfstream Shopping Center New Hanover County Dear Mr. Vincent: William G. Ross Jr., Secretary North Carolina Department of Environment and Natural ReSOlneeti Coleen H. Sullins Director Division of Water Quality The Division of Water Quality issued a Coastal Stormwater Management Permit, Number SW8970305 to Gulf Stream Shopping Center, for a High Density Stormwater pond to serve the Gulf Stream Shopping Center on 7/17/1997. This permit expired on 7/17/2007. Section .1003(h) of 15 A NCAC 2H .1000 (the stormwater rules) requires that applications for permit renewals shall be submitted 180 days prior to the expiration of a permit and must be accompanied by a processing fee, which is currently set at $420.00. If this is still an active project please complete and submit the enclosed renewal application in a timely manner. If this project has not been constructed and a permit is no longer needed, please submit a request to have the permit rescinded. If you have sold the project, or are no longer the permittee, please provide the name, mailing address and phone number of the person or entity that is now responsible for this permit. Enclosed is a form for change of ownership, which should be completed and submitted if the property has changed hands. Your permit requires that upon completion of construction and prior to operation of the permitted treatment units a certification of completion be submitted to the Division from an appropriate designer for the system installed. This is to certify that the permitted facility has been installed in accordance with the permit, the approved plans, specifications and supporting documentation. Please include a copy of the certification with your permit renewal request and processing fee. Enclosed is a copy of a sample certification. Also enclosed is a new Operation and Maintenance agreement that should be completed and submitted along with your renewal application. You should be aware that failure to provide the Designer's Certification and the operation of a stormwater treatment facility without a valid permit, are violations of NC General Statute 143- 215.1 and may result in appropriate enforcement action including the assessment of civil penalties of up to $10,0 �6 per day. If you have any questions, please feel free to contact staff in the stormwater group at 910-796-7215. Sinc ly, t/Stz-4' Ed Beck, Regional Supervisor Surface Water Protection Section Wilmington Regional Office Enclosures No thCarol ina cc: Wilmington Regional Office 111alurally North Carolina Division of Water Quality 127 Cardinal Drive Extension Wilmington, NC 28405 Phone (910) 796-7215 Customer Service Wilmington Regional Office Intemet: www.ncA,ateriluality.ora Fax (910) 350-2004 1-877-623-6748 An Equal OppolunitylA(firmative Action Employer— 50% Recycled110% Post Consumer Paper Michael F. liaslcy, Governor �CF W A T4S;gQ �O G 7 February 12, 2008 Mr. Jon T. Vincent, Owner Gulf Stream Shopping Center 1508 Military Cutoff road, Suite 302 Wilmington, NC 28403-5730 Notice of Inspection -NON-COMPLIANCE STATUS Gulfstream Shopping Center Stormwater Project No. SW8970305 New Hanover County Dear Mr. Vincent: William G. Ross Jr., Secretary North Carolina Department of Environment and Natural Resources Coleen 11. Sullins Director Division of Water Quality Please find attached a copy of the completed form entitled "Stormwater Compliance Inspection Report". The report summarizes the findings of a recent inspection of the project's stormwater controls conducted on February 1, 2008 to determine compliance with Stormwater Permit Number SW8970305 issued on July 17, 1997. The required actions that are necessary to bring this site into compliance are noted under the Comments section of the report. Please inform this Office in writing within fifteen (15) days of the specific actions that will be undertaken and the time frame that will be required to correct the deficiencies. Failure to provide the requested information, when required, may initiate enforcement action. If you have any questions please contact David Cox at the Wilmington Regional Office, telephone number (910) 796-7318. Sincerely, Pat C. Durrett Environmental Specialist PCD/encl: SAWQSISTORMWATIINSPECT1Pats inspections\SW8970305 cov Itr cc: Wilmington Regional Office nc NoSthCarolina ,11aturn!!y North Carolina Division of Water Quality 127 Cardinal Drive Extension Wilmington, NC 28405 Phone (910) 796-72 t5 Cusiomer Service Wilmington Regional Office Internet: www.ncwaleruuality.oFax (910)350-2004 1-977-623-6748 An Equal Opportunity/Affirmative Action Employer— 50% Recycled110% Post Consumer Paper HIGH DENSITY STATE STORMWATER INSPECTION REPORT Project Name: _ Gulfstream Shopping Center Permit No: SW8970305 Exlpiration date: 7117107 Contact Person: Jon T. Vincent Phone No: County: New Hanover Center of Project GPS: Lat: 340 19' 55.61 "N Long: 770 45' 02.02 "W Facility Address: .5315 S. College Rd. _ _ Cam: Wilmington Zip: 28412 (If multiple basins exist, specify basin(s): Entry time: 12:00 am ❑ pm ® Exit time: 12:40 - am ❑ pm ® Date: 2-11/08 Method of Treatment: (check one) ® Wet Detention ❑ Dry Detention ❑ Bioretention ❑ Wetland ❑ Sandfilter ❑ Swale ❑ Pocket Wetland ❑ Level Spreader ❑ Permeable Pavement ❑ Infiltration Basin Other: ❑ Receiving Waters: UT to Cape Fear . Classification: SC River Basin: Cape Fear GENERAL QUESTIONS FILE REVIEW 1. A signed copy of the Engineer's certification is in the files: 2. A signed copy of the Operation & Maintenance Agreement is in the files: 3. A copy of the recorded deed restrictions is in the files: SITE VISIT 1. Drainage area is consistent with the permit: 2. Built -upon area to drainage area is consistent with the permit: 3. All built -upon area (as permitted) is graded such that the runoff drains to the system: 4. The outlet structure is located per the approved plans: S. The trash rack is provided on the outlet/bypass structure: 6. The trash rack is free of debris and excess trash: 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: YES NO NA NE ❑ ❑ ® ❑ ® ❑ ❑ ❑ 0 ❑ ❑ 0 YES NO NA NE 10. Access points are clear and well maintained: ® ❑ ❑ ❑ 11. Forebay is free of excessive sediment: ® ❑ ❑ ❑ 12. Banks are stable with no erosion present: ® ❑ ❑ ❑ 13. Vegetation and trash have been removed as needed: ❑ ® ❑ ❑ 14. Drawdown device is correctly sized per the approved plans: *verify ® ❑ ❑ ❑ 15. Grass is mowed (not scalped) as required: ® ❑ ❑ ❑ 16. All required parts of the system are provided (such as vegetated shelf and a Forebay): ® ❑ ❑ ❑ 17. The Swale or outlet bypass is in the correct place and is in good condition: ❑ ❑ ® ❑ 18. Vegetated shelf is 6:1 and properly vegetated: ® ❑ ❑ ❑ 19. Invasive species/tree control is provided as needed ® ❑ ❑ ❑ 20. Tree pruning, mulch and plant replacement are provided as needed in the bioretention basin: ❑ ❑ ® ❑ 21. permeable pavement has had regular sweeping and vacuuming: ❑ ❑ ® ❑ 22. Gravel replacement is performed as needed: ❑ ❑ ® ❑ 23. Excessive landscape debris (grass clippings, leaves, & sediment) are controlled: ❑ ❑ ® ❑ 24. Large stemmed vegetation is kept off of the level spreader: ❑ ❑ ® ❑ 25. Sediment and debris is removed from behind the lip of the level spreader on a routine basis: ❑ ❑ ® ❑ 26. Maintenance records are available for inspection: - ❑ ® ❑ ❑ S COMMENTS: each NO answer should have a comment 1. Your permit expired on 7/17/07. To date, this Office has not received a renewal request. Operation of a system without a valid permit is a violation. You must at once, submit your renewal as required. 2. A signed copy of the Engineer's certification has not been submitted as required. This must be provided with your renewal request, also, a signed copy of the new Operation and Maintenance form should be provided. 3. Overall the site looked good. The trash rack has been bent and should be repaired. Some trash was evident on the rack and the surrounding area that should be removed. 4. * The orifice size should be checked. The permitted size is a 1" opening. Please verify that this is correct. S. No maintenance records were available on the inspection date. You are reminded that records must be kept as required in your permit. _Outlet structure forebay and berm inlet to forebay as approved Other end of forebay with inlets as approved sideslopes and shelf Trash rack and outlet structure orifice shown trash in pond YES NO Compliant ❑ Non -Compliant ® NOV sent ❑ ® Date sent NOV Inspectors name& signature: Pat C Durrett _ Date: 2/1/08 t. f' 711197 SLS Sife Characteristics: Total Drainage Area (DA) sq. ft. acres 81,422 1.87 Impervious Area Land Use sq. ft. acres building (proposed retail) 8,100 0.19 building awn shop) 5,925 0.14 asphalt 43,485 1,00 concrete 8,140 0.19 Toiaflj 65,650 11.51 Pond Characteristics: Depth at permanent pool = 7.0 ft, side slopes = 3 :1 Required surface area at normal pool = (SA/DA) x (total tract area) 2,809 sq. ft. Pond Size: WALMART WEST Detention Pond Sizing Elevation (ft.) Length ft.) Width (ft.) Surface Area (sq. ft.) Normal Pool 29.0 67 42 2,814.0 Top of Vag. Filter 29.5 73 48 3,504.0 Flood Pool 30.6 79.6 54.6 4,346.2 Top of Bank 31.1 1 82.6 57.6 1 4,757.3 Boftom of Pool 22.0 1 25 0 1 0.0 For first 1" of runoff over impervious area: Required storage volume above normal pool = 1(1/12) x (DA) x (% imp.)] + [(1112) x (DA) x (1-% imp.) x C] C=0.2 5,738 cu. ft. Forebay % impervious = 0.807 = 80.7% (use) 81% REQ'D landscaping area = 3,479 sq. ft. Actual landscaping area = 3,573 sq. ft. for 81 % Density, SAIDA = 0.0345 (chart for 90% TSS Removal for Wet Detention without Vegetative Filter Frovided Storage: Voi.F;nu _ [(Normal pool SA + Filter SA) 1 2] x (Filter elev. - N.P. elev.) — 1,580 cu. ft. Vol.FWd = [(Fiiter SA + Flood Pcoi SA) 12] x (F.P. elev. - Filter elev.) = 4,318 cu. ft. Total Vol. = 5.897 cu. ft. Required storage volume = 20% of required storage volume 1,148 cu. ft. Required Surface area = 20% of normal pool SA 562.8 sq. ft. Depth STORMWATER �����►rlulfr'lrryi CAgO��,,��� :a SEAL �•`•.c�,y17314 Q :� Rio ••.G/N�EQ':••4Q �� E C E 1 V E `� v JUL 0 21997 PRO,i # ,sLQgC('7o3o5 9697 9697 Pond � o � 2— 711 /97 SLS WALMART WEST Outlet Structure Design 9697 Site Characteristics: Drainage Area DA s . ft. acres 81,422 1.87 % Impervious = 0.806 80.6 % Pond Size: Elevation ft. Surface Area /-- ft. Normal Pool 29 2,814 Flood Pool 30.6 4,346 Outlet Structure: Q 2day = Provided Vol. / 172,800 sec. 0.034 cfs Area of pipe = Q / [Cd x SQRT(2 x g x h)] Cd = 0.6 g = 32.2 ft./s2 h = (F.P. elev. - N.P. elev.) / 2 - 0.80 ft. A 2 day = 0.0079 sq. ft. DIA. Of pipe = SQRT[(A x 4) / pi] 0.1004 ft. 2 daY = 1.21 in. Outlet Structure Check: Using a 4' x 4' Basin, Perimeter (L) = 16 ft. Impervious Area s . ft. acres 65,650 1.51 Provided Storage Volume = 5,897 cu. ft. Q sday = Provided Vol. / 432,000 sec. = 0.014 cfs A sday = 0.0032 sq. ft. DIA. Of pipe = SQRT[(A x 4) / pi] 0.0635 ft. 0.76 in. U S C— C� 21�1C_E Q = CIA C = (% imp.)(.95) + (1-% imp.)(.25) - 0.82 I = 6.3 in. for a 10 yr. Storm A = 1.87 Acres 9.60 cfs Q= CwxLxH"5 H = [Q / (Cw x L)]213 Cw = 3 0.34 ft. Peak elevation = flood pool elevation + H 30.94 ft. -�0•9u' '�- -Sl. � T- �Uoa,n outletstr .pb STORM DRAINAGE DESIGN DATA SHEET PROJECT_ WAI-MA IZT \619-Sr COMPUTED BY�Lav-,c2 S --v-, N DATE S —ZZ , 7 LOCATION_CARa1-lAya &cdg:d _QCHECKED ©Y SHEET OF—L—. STORM FREQUENCY YRS. LOCATION AREA(ACRE) C INTENSITY Q-CIA (C.F.S. REQ'D) PIPE DATA REMARKS FROM TO SUB TOTAL TOTAL F� L I TYPE N. S 7. LENGTH SIZE VEL. (OF Q E 4'D Q AVAIL. CT i Cl 2 0.2Lf 1 0-5 5 12 -' j V' 1. 5 2.7 CT- 'L per^' o 0.-48 0. sZ CL 3 pa"'D D,30 23` PD No S+,MN 1 .6a 9.37 1,60 11. 0 ,o-7 o,-1 u.:f o.u9 t 3q I IS`` 2 3 G:7 SIaMVkk L) iTFALL Z . V m v C — RUNOFF COEFFICIENT N - COEFFICiENT OF FRICTION It - IIEIGIIT ABOVE IIILET OF MOST REMOTE P0114T S - SLOPE (x) L - LENGDI OF DRA114AGE AREA 0 - FLOW (C.F.S.) I — EN fi_NSITY OF S IORIA (INC1ics) NOTE: DESIGN IS BAST% 111E SUM OF III[ AND 1101 111E SU III[ OISCIIARGES. *: �, i.. _ r 4 JA3e 6I5/97 WALMART WEST 9697 SLS Detention Pond Sizing Site Characteristics: Total Drainage Area DA sq. ft. acres 81,422 1.87 Impervious Area Land Use sq. ft. acres buildin(proposed retail 8,100 0.19 buildin awn shop) 5,925 0.14 asphalt 43,485 1.00 concrete 8,140 0.19 Total 65,650 i 1.51 Pond Characteristics: Depth at permanent pool = 6.5 ft. side slopes = 3 :1 Required surface area at normal pool = (SAIDA) x (total tract area) = 3,306 sq. ft. Pond Size: Elevation (ft.) Length (ft. Width ft.) Surface Area (sq. ft. Normal Pool 29.0 74 45 3,330.0 Flood Pool 30.5 83 54 4,482.0 Top of Bank 31.1 86.6 57.6 4,988.2 Bottom of Pool 22.5 29 0 0.0 For first 1" of runoff over impervious area: Required storage volume above normal pool = [(1112) x (DA) x (% imp.)] + [(1I12) x (DA) x (1-% imp.) x C] , C = 0.2 5,738 cu. ft. Required storage volume = 20% of required storage volume 1,148 cu. ft. Surface area = 20% of normal pool SA = 666 sq. ft. depth= 3.5ft, % impervious = 0.807 = 80.7% use 81 % REQ'D landscaping area = 3,479 sq. ft. Actual landscaping area = 3,533 sq. ft. for 83% Density, SAIDA = 0.0406 (chart for 90% TSS Removal for Wet Detention without Vegetative Filter Provided storage volume above normal pool = [(normal SA + flood SA)12] x (F.Pool elev. - N.Pool elev.) = 5,859 cu. ft. Provided storage volume = (SA / 2) x Depth 1,166 cu. ft. 9697 Pond 1 of 1 615197 WALMART WEST 9697 SLS Outlet Structure Design Site Characteristics Drainage Area DA s . ft. acres 81,422 1.87 % Impervious = 0.806 = 80.6% Pond Size' Elevation ft. Surface Area (sq. ft. Normal Pool 29 3,330 Flood Pool 30.5 4,482 Im envious Area s . ft. acres 65,660 1.51 Provided Storage Volume = 5,859 cu. ft. Outlet Structure: Q = Provided Vol. / 172,800 sec.(2-day drawdown) = 0.034 cfs Area of pipe = Q / [Cd x SQRT(2 x g x h)] Cd = 0.6 g = 32.2 ft./s2 h = (F.P. elev. - N.P. elev.) / 2 = 0.75 ft. A = 0.0081 sq. ft. DIA. Of pipe = SQRT[(A )< 4) / pi) 0.1017 ft. 1.22 in. Outlet Structure Check: Using a 4' x 4' Basin, Perimeter L = 16 ft. Q = CIA C = (% imp.)(.95) + (1-% imp.)(25) = 0.82 1 = 6.3 in. for a 10 yr. Storm A = 1.87 Acres — 9.60 cfs Q= CwxLxH"5 H = [Q / (Cw x L)]2r3 Cw = 3 = 0, 34 ft. Peak elevation = flood pool elevation + H = 30.84 ft. Energy Dissipators C.I. 2 to Pond: Q = 2.72 cfs pipe dia. = 15 in. Velocity = 1.39 fps zone 1 L= LA-iO W= 3yD:� 3.-75' C.I. 3 to Pond: Q = 4.71 cfs pipe dia. = 18 in. Velocity = 2.00 fps zone 1 L-7-- LI-4-D 0' outletstr 1 of i Date Job TRIPP RIGMEMG, P.C. W A I M A RT W C- ST 507 Chestnut Street For Wilmington, North Carolina 26401 s L� II SC-7 Design Sheet SL S of Check Job No.. p5 �or\e