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HomeMy WebLinkAboutSW8060405_COMPLIANCE_20060503STORMWATER DIVISION CODING SHEET POST -CONSTRUCTION PERMITS PERMIT NO. SW DOC TYPE ❑ CURRENT PERMIT ❑ APPROVED PLANS ❑ HISTORICAL FILE F�ICOMPLIANCE EVALUATION INSPECTION DOC DATE -:2eC SZ� YYYYMMDD INFILTRATION TRENCH ANALYSIS Filename: S:IWPDATAIWQSIINTRENCH1060405 Project # SW8 060405 Project Name Anchor Medical Center Recvng Stream UT Dutchman Crk Outlet Channel Drainage Basin Cape Fear Site Area 1.84 acres Impervious Area Calculation Date 03-May-06 Reviewer P.Bartlett Classification SA' HQW Index # 18-88-9-3-3 Drainage Area 54,886 SF 1.26 Acres Rational Cc (list C after each BUA) Buildings 14960 0.95 Streets 1 OS Prkg 34533 0.95 OS sidewalks 1915 0.95 Total 1'408' % Impervious: 93.7% Volume/Storage Calculation If Rational Method is used, place a 1 in this box Required Provided Design Storm RV Volume to Store Pipe Diameter Length Of a Single run of Pipe Number of Pipe Runs in Trench Storage In Piping Total Storage in Piping Cross -Sectional Area Of Pipe Runs Length Of Trench Width Of Trench Height Of Trench Cross -Sectional Area Of Trench Voids Volume, 40% Total Voids Volume Total Volume Provided Elevation Of Bottom Of Trench Elevation Of SHWT Overflow Elevation Exfiltration Rate/ Drawdown Reported Hydraulic Conductivity Bottom Surface Area Drawdown Time 25 YEAR 24 HOUR STORM NIA Intensity, i = .33 inches / hour Qr=CiA= Qp through the bottom of the basin= 10 YEAR 10 MIN HIGH INTENSITY EVENT Intensity, i = 6.3 inches / hour Volume for 10 yr. 10 min. event = Cc: 0.87 1.5 in 0.89 6!'116 CF Pipe Size 1 Pipe Size 2 2 Feet 150 Feet 8 each 0 3770 Cubic Feet €37s70. Cubic Feet 0.000 25.133 SF 150 Feet 30.06 Feet 2.67 Feet 0.00 80.26 SF 3308 0.36 CFS 1.8997 CFS 4140.46 CF < CF CF Cubic Feet 014. �111m job 14.7 Mean Sea Level 12.7 Mean Sea Level 17.37 Mean Sea Level 1.5167 Cubic Feet Per Hour Per Sq Ft 4509.0 Square Feet ]hours Must be > Qr 7078 CF P6nd Report 6 hiydraflow Hydrographs by Intelisolve Pond No. 'I - INFILTRATION BASIN Pond Data Bottom LxW = 150.0 x 30.1 ft Side slope = 0.0:1 Stage 1 Storage Table Monday, Apr 3 2006, 6:44 PM Bottom elev: = 14.70 ft Depth = 2.67 ft Stage (ft) Elevation (ft) Contour area (sgft) Iner. Storage (tuft)" Total storage (tuft)" ("58.80% voids applied) 0.00 14.70 4,509 0 0 0.13 14.83 4,509 354 354 0.27 14.97 4,509 354 708 0.40 15.10 4,509 354 1,062 0.53 15.23 4,509 354 1,416 0.67 15.37 4,5C9 354 1,770 0.80 15.50 4,509 354 2,124 0.93 15.63 4,509 354 2,478 1.07 15.77 4,509 354 2,832 1.20 15.90 4,509 354 3,186 1.34 16.04 4,509 354 3,539 1.47 16.17 4.509 354 3,893 1.60 16.30 4,509 354 4,247 1,74 1G.44 4,509 354 4,601 1.87 16.57 4,509 354 4,955 2.00 16,70 4,509 354 5,309 2.14 16.84 4,509 354 5,663 2.27 16.97 4,509 354 6,017 2.40 17.10 4,509 354 6,371 2.54 17.24 4,509 354 6,725 2.67 17.37 4,509 354 7,079 Culvert / Orifice Structures Weir Structures [A] [D] [C] [D] [A] [a] [C] [D] Rise (in) = 0.00 0.00 0.00 0.00 Crest Len (ft) = 0.00 0.00 0.00 0.00 Shan (in) = 0.00 0.00 0.00 0.00 Crest El. (ft) = 0.00 0.00 0.00 0.00 No, Barrels = 0 0 0 0 Weir Coeff. = 3.33 0.00 0,00 0.00 Invert El. (ft) = 0.00 0.00 0.00 0.00 Weir Type = --- --- --- Length (ft) = 0.00 0.00 0.00 0.00 Multi -Stage = No No No No Slope (%) = 0.00 0.00 0.00 0.00 N-Value = .013 .000 .000 .000 Crif. Coeff. = 0.60 0.00 0.00 0.00 Multi -Stage = nla No No No Exfiltration = 18.200 inlhr (Wet area) Tailwater Elev. = 0.00 ft Nola: CulverllOrifica outflows have been analyzed under inlet and outlet control. Stage 1 Storage 1 Discharge Table Stage Storage Elevation Clv A Clv 8 Civ C Clv D Wr A Wr B Wr C Wr D Exfil Total ft tuft ft cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs 0.00 0 14.70 --- --- --- --- --- --- --- 0.000 0.00 0.13 354 14.83 --- --- -- --- --- --- --- --- 1.243 1.24 0.27 708 14.97 --- --- -- --- --- --- --- --- 1.253 1.25 0.40 1,062 15.10 --- --- --- -- --- --- --- --- 1.264 1.26 0.53 1,416 15.23 --- --- --- --- --- --- --- --- 1.274 1.27 0.67 1,770 15.37 --- --- --- --- --- --- --- 1,284 1,28 0.80 2,124 15.50 --- --- --- --- --- --- --- 1.295 1.29 0.93 2,478 15.63 --- --- --- --- --- --- --- - 1.305 1.31 1.07 2,832 15.77 --- --- --- --- --- _-_ --- 1.316 1.32 1.20 3,136 15.90 --- --- --- --- --- 1.3215 1.33 1.34 3,539 16.04 --- --- --- --- --- --- --- --- 1.337 1.34 1.47 3,893 16.17 --- --- --- --- --- --- --- --- 1,347 1,35 1.60 4,247 16.30 --- --- --- --- --- --- --- --- 1.358 1.36 1.74 4,601 16.44 --- --- --- - --- --- 1.368 1.37 1.87 4,955 16.57 --- -- --- --- --- --- 1.378 1.38 2.00 5,309 16.70 --- --- - --- --- - - 1.389 1.39 2.14 5,663 16.84 - - - -- 1.399 1.40 2.27 6,017 16.97 - --- 1.410 1.41 2.40 6,371 17.10 --- -- --- 1.420 1.42 2.54 6,725 17.24 --- 1.431 1A3 2.67 7,079 17.37 --- --- --- --- --- --- --- 1.441 1.44 September 28, 2005 Cabe Dear Land Developers, LLC 1135 Military Cutoff' Road, Suite 201 Wilmington, North Carolina 28405 Attention: Mr. Steve Saieed Reference: Doable Ming Infiltrometer Testing 4222 and 4226 Long Beach Road SE Southport, North Carolina Job No. 1063-05-443 Dear Mr. Saieed; In accordance with S&ME. Proposal 905-05 dated August 1, 2005, S&ME personnel have recently performed double -ring infiltrometer tests of the surfieial soils at the subject site at the approximate locations shown in Figiire 1. Specifically, our representatives performed the following work items on Allgllst 23, 2005 and September i, 2005. Advanced four hand-augered borings near the inf iltrometer locations in order to visually classify the in -place soils. The hue and chroma of the recovered soil samples were compared to a Munsell Soil Color Chart. 2. Conducted double -ring infiltrometer testing at two locations at depths of' 11 and 19 inches below the existing ground surface. This testing was conducted in general accordance with American Society for Testing and Materials (ASTM) procedure D-3385 entitled, "Infiltration Rate of Soils in field Using Double - Ring Infiltrometer". Based on our field classifications of the excavated soils at the hand-augered boring locations, the in - place soils consist of slightly silty sands. Water was observed in the borcholes at depths ranging from 3 to 59.5 inches below the existing ground surface. The site water level will fluctuate with climatic and seasonal conditions, however, and may be higher or lower at other times of the year. The average infiltration rate at the test locations were approximately 19.2 and 30.1 inches per Dour. A summary of the field test results is presented in Tables 1 and 2. 5&ME, Inc. (9101 799-9945 6409 Amsterdam Way, Building 3-3 1910) 799-9958 fax Wilmington, North Carolina 28405 www.smelnc.coin Cape fear Land Developers, LLC S&M13 Job Number 1063-05-443 September 28, 2005 Page Two Due to the possibility of previous land disturbances, lateral variations in soil type and consistency over relatively short distances, significant fluctuations in perched water conditions, and possible construction activities in the area, it is difficult to determine a project specific "seasonal high water table". For this reason, we strongly recommend coordination with the North Carolina Division of Waiter Quality prior to final design of the site stormwater system. S&ME appreciates the opportunity to provide our services during this phase of the project. Should you have any questions after reviewing this letter, or if we can be of additional assistance, please do not hesitate to contact us at your convenience. Sincerely, S&ME1, INC. l Philil 13yrc Geoteclinical Department Manager ( 4 Randy Martin, V.E. Branch Manager Ph4B:RGm/jns Attachments E-Mail: Withers & Ravenel, Mr. Brian Campbell beam bell of withersravenel.com TABLE 1 H n d-Auger Borings and Munsell Soil Descriptions 4222 and 4226 Long Beach Roan SE Southport, North Carolina .lob No. 1063-05-443 Depth Location Inches Hue Value/Chroma 1 0-5 2.5 Y 4/2 (8-23-05) 5-48 2.5 Y 6/2 48-66 2.5 Y 5/4 Soil Description Dark grayish brown fine to medium SAND, trace of'silt Light brownish gray fine to medium SAND, trace of silt Light olive brown fine to medium SAND, trace of silt Water was encountered at a depth of 59'/2" below the existing ground surface 2 0-5 2.5 Y 5/2 Grayish brown fine to medium SAND, trace (8-23-05) of silt 5-12 2.5 Y 2.5/1 Black fine to medium SAND, trace of silt With Shell fragments 12-18 2.5 Y 3/2 Very dark grayish brown fine to medium SAND, trace of silt 18-24 2.5 Y 2.5/1 Black fine to medium SAND, some silt (slightly cemented) 24-32 2.5 Y 5/3 Light olive brown fine to medium SAND, trace of silt Water was encountered at a depth of 29" below the existing ground surface. 3 0-5 2.5 Y 2.5/1 Black fine to medium SAND, trace of silt (8-23-05) with organics 5-20 2.5 Y 2.5/1 Black organic material (Neat) Water was encountered at a depth of 3" below the existing ground surface. 4 0-3 2.5 Y (9-07-05) 3-18 2.5 Y 18-50 2.5 Y 4/2 Dark grayish brown fine to medium SAND, trace of silt 4/I Dark gray fine to medium SAND, trace of silt 3/1 Very dark gray fine to medium SAND, trace of silt Water was encountered at a depth of 41" below the existing ground surface. V T ,TABLE 2 Double Rini; InfiltrometerTesting 4222 and 4226 Long Beach [toad SE Southport, North Carolina Job No. 1063-05-443 Location- Il Date of Test: August 23, 2005 Depth of Test Below Site Grade: 19 inches Depth of Water in Rings: 4 inches Inner Diameter of Inner Ring: 1 P/a inches Inner Diameter of Outer Ring: 22%2 inclies Depth to Water: 59% inclies Average Infiltration Rate: 30.1 inchcs per hour Soil Series*: Kureb Reported Depth to High Water'fable*: Greater than 6.0 Feet * As interpreted from the "Soil Survey of Bmnswick County" prepared by the United States Department of Agriculture Soil Conservation Service. Location: 4 Date of Test: September 7, 2005 Depth ofTest Below Site Grade. 1 I inches Depth of Water in Rings: 4 inches Inner Diameter of Inner Ring: 1 13/a inches Inner Diameter of Outer Ring: 22'/z inches Depth to Water: 41 inches Average Infiltration Rate: 18.2 inches per hour Soil Series*: Kureb Reported Depth to I-ligh Water Table*: Greater than 6.0 Feet * As interpreted from the "Soil Survey of Brunswick County" prepared by the United States Department. of Agriculture Soil Conservation Service. i I I E I -------------------------- • � i �-•�-_.��;_ _":_ _nary--�---------r- Fzr- - - — �= - - -- -- -- +:4 - - ��•. Location 9-7-05 Location 2 Si::l. ?P. i_: �.. - ti,r _ � --_- �.. 1-� _~-.•._ I.' - at ryl- l� � I _ Location 3 �/' •%�� I I ------ ,� : _:; ... (8-23-05) ion ! it � 'i• Note: Site plan drawing provided to S&ME by Withers & Ravenel personnel. LEGEND ® Approximate Location of SCALE: NOT TO SCALE DOUBLE -RING INFILTROMETER TESTING FIGUPE Infiltrometer Testing CHECKED BY: RGM 4222& 4226 LONG BEACH ROAD SE NUMBER 8-23-05 and 9-7-05 <} `<':Y SOUTHPORT, NORTH CAROLINA © Approximate Location of DRAWN BY: JNS F,NGUNEERUNG . TESTING Hand -Auger Boring (8-23-05) DATE: 9-28-05 E•NVIRONMENTALSL12'-'10Es JOB NUMBER: 1063-05-443