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HomeMy WebLinkAboutSW8021116_Compliance Evaluation Inspection_20030404INFILTRATION BASIN ANALYSIS FILENAME: G:\DATA\WPDATA\WQS\INBASIN\021116-1.WK1 PROJECT NUMBER: 021116-1 DATE: 04-Apr-03 PROJECT NAME: The Gauntlet Clubhouse Tennis Courts DRAINAGE BASIN: Cape Fear REVIEWER: L. Lewis RECEIVING STREAM: Beaver Dam Creek CLASS: SA Index No.: CPF17 18-88-9-1-(1.5) If ORW, is site within the 575' AEC? SITE AREA 1.64 acres DRAINAGE AREA: `: `'.( SF IMPERVIOUS AREA CALCULATION Rational C BUILDINGS PARKING/ASPHALT CONCRETE Tennis Courts TOTAL % IMPERVIOUS, 1= ELEVATION OF SEASONAL HIGH WATER TABLE REPORTED INFILTRATION RATE SURFACE AREAS AND ELEVATIONS Elev. (ft) Area, sq ft Inc. Volume Acc. Volume BOTTOM 8.25 3502 0 8.5 4814 1039.5 1039.5 TOP 8.75 6587 1425.125 2464.625 VOLUME / DEPTH / DRAWDOWN CALCULATION DESIGN STORM, INCHES DESIGN VOLUME TOTAL VOLUME AVAILABLE DEPTH OF RUNOFF TIME TO DRAWDOWN 25 YEAR 24 HOUR STORM N/A 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 = CUBIC FEET CUBIC FEET FEET HOURS MUST BE <120 0.16 CFS 0.49 CFS Must be > Qr 1828.77 CF < 2522.25 CF COMMENTS Volume and drawdown are (not) within Design Requirements. INFILTRATION BASIN ANALYSIS FILENAME: G:\DATA\WPDATA\WQS\INBASIN\021116-2.WK1 PROJECT NUMBER: 021116-2 DATE: 04-Apr-03 PROJECT NAME: The Gauntlet Clubhouse Tennis Courts DRAINAGE BASIN: Cape Fear REV!EVVER: L. Lewis RECEIVING STREAM: Beaver Dam Creek CLASS: SA Index No.: CPF17 18-88-9-1-(1.5) If ORW, is site within the 575' AEC? SITE AREA 1.64 acres DRAINAGE AREA: `r ` SF IMPERVIOUS AREA CALCULATION Rational C BUILDINGS 131 1 PARKING/ASPHALT CONCRETE 305 1 Tennis Courts TOTAL Place a "1" here if Rational % IMPERVIOUS,I= RV= ELEVATION OF SEASONAL HIGH WATER TABLE <' FEET MSL REPORTED INFILTRATION RATE ..; :. INCHES/HOUR or 0.000139 FPS SURFACE AREAS AND ELEVATIONS Elev. (ft) Area, sq ft Inc. Volume Acc. Volume BOTTOM 8.25 94 0 8.5 415 63.625 63.625 TOP 8.75 813 153.5 217.125 VOLUME I DEPTH / DRAWDOWN CALCULATION DESIGN STORM, INCHES DESIGN VOLUME :.:::;<:>'I'''. CUBIC FEET TOTAL VOLUME AVAILABLE €: ;' 17, CUBIC FEET DEPTH OF RUNOFF TIME TO DRAWDOWN ..':;; fi HOURS MUST BE <120 25 YEAR 24 HOUR STORM NIA Intensity, i = .33 inches / hour Qr-CiA= 0.01 CFS Op through the bottom of the basin= 0.01 CFS Must be > Qr 10 YEAR 10 MIN HIGH INTENSITY EVENT Intensity, i = 6.3 inches! hour Volume for 10 yr. 10 min. event = 98.30 CF < 217 CF COMMENTS Volume and drawdown are (not) within Design Requirements. Storm Water / Erosion Control / Soils report Design Narrative and Calculations Subject: Additional Tennis Courts For The Gauntlet Golf Course Clubhouse Site Brunswick County, North Carolina Prepared for St. James Plantation. P.O. Box 10879 Southport, North Carolina 28461 (910) 253-7600 Date: November 8, 2002 Prepared by Cape Fear Engineering, Inc. 151 Poole Road, Suite 100 Beiviile, North Carolina 28451 (910) 383-1044 RECEIVED NOV 2 0 2002 DWQ PROD # SW ? 0 2 111(-p DESIGN NARRATIVE L GENERAL: The project site is located off of Beaver Creek drive at the Gauntlet Golf Course Clubhouse site with in the St. James Plantation development. St. James Plantation is located along NC Hwy 211 within Brunswick County, North Carolina. The project area in question is approximately 0.8 acres. Drainage considerations are to be in accordance with DEM 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 grasses and minor ground cover 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 new clay tennis court with a 4' wide concrete sidewalk and a wooden prefabricated gazebo. Two shallow infiltration swales are proposed to be graded in this location as shown on the attached plan to trap sediment during the construction process until vegetation has been established and to capture and treat storm water as a permanent storm water management device. 4. DRAINAGE CALCULATION CONSIDERATIONS: Attached to this design narrative are the drainage calculations determining the amount of storm water to be contained and treated prior to entering any downstream surface waters. The design utilized for this project is two infiltration swales that will capture and treat the runoff of a 24-hr 25-yr storm event. A vegetative swale has been designed at the end of the infiltration swales as a bypass for any storm event that would exceed the design parameters. 5. EROSION CONTROL CONSIDERATIONS: The proposed infiltration swale will be used as a trapping device during construction and has sufficient storage for. the calculated amount of disturbance. Also, the perimeter will be enclosed in .silt fence as added protection. The area of disturbance is limited to within the silt fence boundary. Maximum graded slope is not to exceed three (3) to one (1) with vegetative establishment a priority.. Page One Design Narrative St. James Plantation The Gauntlet Clubhouse Site 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 permanent ground cover will be a priority. 7. SOILS REPORT: The attached soils information taken from the Brunswick County Soils Survey book along with a site inspection was utilized to design the proposed infiltration swales. During the site visit borings were made at the locations of the two proposed infiltration swales. Ground water was encountered at approximately 24" below the existing top of grade which was surveyed at an elevation of approximately 8.0 msl. The soils are identified as Leon which has a permeability rate of 6 to 20 inches per hour. For this design 6 inches per hour has been used in the calculations of the infiltration swales. Page Two Design Narrative St. James Plantation The Gauntlet Clubhouse Site Z n O (Joins sheet 17, � 3 r 0 A O C Cr O E m O � S a m 3 m r -r O ° •F 3 3 o O 3 3 a 3 3 r a s ° r .n o r 0 2 0 3 / o U m o ` m r a 0 I D m r _ g m o f ,' o. L7j m r m ' O D Z rn r a m o a // p 4 l ° a :2 E m m c C a m o 0 xo Tq - � D' m i � t 3rr �.4 •F (m •Ys „�. o C . �.. t r m m IU O i fi J i Jvtuef4 COS. A Z m Brunswick County, North Carolina 115 TABLE 17.--PHYSICAL AND CHEMICAL PROPERTIES OF THE SOILS --Continued Map symbol and IDepthlClay I Moist I Permea- IAvailablel Soil 1SalinitylShrink-swell soil name i i ± bulk I bility water (reaction! i potential density ca acit I In I Pct I cm I In hr I In in 1 pH Jo---------------1 0-131 5-1511.45-1.651 2.0-6.0 10.10-0.1514.5-5.5 Johns 113-38118-3511.40-1.601 0.6-20 10.12-0.1514.5-5.5 38-701 2-1011.60-1.751 6.0-26 10.03-0.0614.5-5.5 KrB-------------- 1 0-801 0-3 11.60-1:801 6.0-20 1 <0.05 14.5-7.3 Kureb 1 I I I 1 1 LA --------------- I 0-551 --- 10.05-0.501 2.0-6.0 10.20-0.50136-8.4 Lafitte �55-72130-8510.50-1.001 <0.06 10.15-0.'2016:1-8.4 Lo---------------i 0-801 1-6 11.40-1.651 6.0-20 10.02-0.0513.6-5:5 ' Leon Lu------ --------- I 0-181 4-1811.55-1.70i 2.0-6.0 10.08-0.1214.5-5.5 4 Lumbee 18-38 18-35 1.30-1 45 0.6-2 0 0.12-0 16 4.5-5.5 s i38-801 1-10i1.60-1.75i 6.0-20 10.03-0.0614.5-5.5 LY--------------- 1 0-161 5-2011.30-1.60i 2.0-6.0 `0.09-0.1313.6-5.5 Lynchburg 116-80118-3511.30-1.501 0.6-2.0 10.12-0.1613.6-5.5 Ma---------------+ 0-181 <3 11.35-1.651 6.0-20 10.03-0.0713.6-6.0 Mandarin 18-35 2-9 1.45-1 60 0.6-2 0 0.10-0.15 3.6-6.0 135-621 <3 11.35-1"451 0.6-26 10.03-0.0714.5-7.3 62-801 2-9 11.45-1.601 0.6-20 10.10-0.1514.5-7.3 • Mk---------------' 0-6 110-251 --- 1 0.6-2.0 10.09-0.1515.1-7.3 Muckalee i 6-651 5-201 --- 1 0.6-2.0 10.08-0.1215.6-8.4 1sMu--------------- 1 0-5 1 2-8 11.20-1 401 6.0-20 10.15-0 2013.E-5.5 Murville 1 5-801 2-8 11.60-1.751 2.0-6.0 10.05-0.0913.6-5.5 KeE, NhE---------1 0-801 --- 11.60-1.75� >20 1 <0.05 13.6-7.8 Newhan I I MOB -------------- 1 0-161 2-8 Norfolk 116-63118-35 Onslow 'aA------ Pactolus h------- Pantego t. Pits 163-80 ------1 0-171 5-15 117-65115-35 165-801 --- ------1 0-551 2-12 I55-801 2-12 ------1 0-111 5-151 111-15118-351 15-80118-40 I I I I I I ------1 0-151 5-201 115-72118-351 72-80118-40 ------I 0-121 2-8 1 112-231 5-151 123-80: 2-8 ! '1.55-1.75 !1.35-1.45 1.45-1.65 1.30-1.50 1.60-1.75 1.60-1.75 1.20-1.401 1.30-1.401 1.25-1.40; 1.30-1.60' 1.30-1.501 1.30-1.50! 1.60-1.75' 1.45-1.65I 1.60-1.75; 6.0-20 '0.06-0 11 0.6_2.0 10.10-0.15 2.0-6.0 10.11_0.15 0.6_2.0 10.12-0.171 I I 6.0-20 I0.05-0 101 6.0-20 10.03-0.07 2.0+6.0 10.20-0 301 0.6-2.0 10.12-0 201 0.6-2.0 ;0.15-0.20, 2.0-6.0 0.6-2.0 0.6-2.0 6.0-20 2.0-6.0 6.0-20 0.10-0.141 0.11-0.151 0.10-0.15I 0.04-0.10i, 0.10-0.141, 0.04-0.081, 4.5-6.0 4.5_5.5 3.6-5.5 3.6_5.5 4.5-6.0 4.5-5.5 3.6-5.5 3.6-5.5 3.6-5.5 1.5-6.5 E. 5-5.5 1.5-5.5 1.5-5.5 1.5-5.5 1.5-6.5 factors 'Organic I � matter K 1 T I 1 1 I - <2 ILow--------- I0.20 1 5 ' .5-2 <2 `Low---------10.10 I I <2 'LOW --------- 10.10 i 5 i <2 I I I I 4-8 'Low---------i---- 1 --- 1 30-70 8-16 ;High -------- 10.32 <2 !LOW --------- 10.10 ; 5 11 .5-.4 <2 <2 <2 <2 <2 <2 <2 <2 <2 <2 -<2 <2 -<2 <2 <2 <2 <2 <2 <2 <2 <2 <2 <2 <2 Low--------- Low---------' Low--------- Low---------� 0 24 -10.32 •10.10 10.20 -10.20 10.10 10.15 10.10 10.15 10.20 0.20 10.10 0.10 10.10 0.20 0_24 10.20 0.24 0.10 0.10 0.10 0.28 0.28 0.20 0.24 0.28 0.10 ' D.15 1 D.10 i 5 1 2-4 I 5 i .5-5 .I -5- 1 -3- 5 1 I 9-20 I I .5 i .5-2 I 4 i .5-2 5 1 1-6 5 i .5-2 I Storm Water and Erosion Control Calculations INFILTRATION BASIN - Schueler Method Design Calculations for The Gauntlet Clubhouse Tennis Court Site, High Density Area, Infiltration Swale BASIN DATA Proj No.700-19 11 /18/02 infiltswale-#1.xls 1 of4 yr-image weu uesignation: DRAINAGE AREA Swale Designation: In#iittration Swale #1 Keceivmg stream class � AJ waters Onsite Area = 0. r 0 acres Onsite Impervious Area = 0.43, acres Offsite Area = 0.00' acres Offsite Impervious Area = 0.00;acres Total Area = Total Impervious Area = Percent Impervious = Impervious drainage area (acres)/Drainage area (acres) _ 0.70 acres 0.43 acres 61.4 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 = Drainage area (acres) / Impervious portion of the drainage area (acres) Rv = 0.05 + 0.009(1) Rv = 0.05 + 0.009 * 61.4 = 0.603 (in/in) Volume to be controlled from the design storm event. where: Design rainfall Rv Drainage Area 1.5 (in) = 0.603 (in/in) 0.70 (acres) Volume required (cf) = rainfall (in) x Rv (in/in) x Drainage Area (acre) x 1/12(feet/inches) x 43560 (sf/acre) Vreq'd = 1.5 * 0.603 * 0.7 * 1/12 * 43560 = 2298 cubic feet INFILTRATION BASIN - Schueler Method Design Calculations for The Gauntlet Clubhouse Tennis Court Site, High Density Area, Infiltration Swale Determine the volume of the proposed pond/swale: POND GEOMETRY coniour contour Comments Elevation Area (msl) (sf) Elevation 8.25 3502 8.5 4814 Elevation 8.75 6587 of Pon IlCompare volume proposed to volume required from the design storm event. Proj No.700-19 11 /18/02 infiltswale-#1.xis 2of4 Incremental Storage (cf) 1040 1425 2465 cubic = 2465 cf > Vreq'd = 2298 cf (OK -proposed basin volume is greater than minimum required volume) INFILTRATION BASIN - Schueler Method Design Calculations for The Gauntlet Clubhouse Tennis Court Site, High Density Area, Infiltration Swale Pro] No.700-19 11/18/02 infiltswale-#1.xls 3of4 B) Check pond 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 ] / Sum[A] Description AREA C CA impervious Area 0.43 0 0.409 Pervious Area 0.27 0.30 0.081 Sum A = 0.7 Sum CA = 0.49 C ave = 0.49 / 0.7 = 0.699 Determine required discharge from 25 year-24 hour storm event. Q regd = Cavg x I x A Q regd = 0.70 * 0.33 * 0.7 = 0.16 cfs where: I = intensity for 25 year-24 hour storm event from Chart E-6 = 0.33 in/hr A = drainage area = = 0.7 acres Cavg = weighted coefficient of runoff = 0.70 Check available rate of infiltration provided by proposed swale: where: I = infiltration rate of soil (4 to 12 in/hr per Soils Report) Use: = 6 in/hr A = bottom area of swale = = 1959 sf Qavail = IA = 6 in/hr 1959 sf * 1 ft/12 in * 1 hr/3600sec = 0.27 cfs ire rate of infiltration with runoff rate from the 25 year storm event: 0.27 cf > Q regd = 0.16 cf (OK -No Discharge for 25 yr-24 hr storm event) INFILTRATION BASIN - Schueler Method Design Calculations for The Gauntlet Clubhouse Tennis Court Site, High Density Area, Infiltration Swale Proj No.700-19 11 /18/02 infiltswale-#1.xls 4of4 C) Check the 10 year-10 minute storm event to confirm that basin has capacity without flushing system where: I = intensity for 10 year-10 minute storm event from Chart E-6 6. in/hr A = drainage area = = 0.7 acres Cavg = weighted coefficient of runoff = 0.70 Determine discharge rate from 10 year-10 minute storm event: Q 10-yr = Cavg x I x A Q 10-yr = 0.70 * 6.3 0.7 = 3.08 cfs Determine discharge volume from 10 year-10 minute storm event: V 1u-yr = Q 1u-yr * 10 min. duration * 60 sec/min. 1850 cf Check available volume of the proposed infiltration basin: V avail = design volume (from geometry table) = 2465 cf Compare design volume of infiltration basin to discharge volume from 10 year storm event of 10 minute duration: Vavail = 2465 cfs > V 10-yr = 1850 cfs (OK -basin has adequate capacity for 10-yr event without flushing) Compare infiltration system drawdown time to maximum drawdown period of 5 days T = V reqd / Q avail * 1 hr/ 3600 sec T _ 2298 cf / 0.27 cfs 1 hr/ 3600 sec (OK- system draws down in less than 5 days) 2.35 hours INFILTRATION BASIN - Schueler Method Design Calculations for The Gauntlet Clubhouse Tennis Court Site, High Density Area, Infiltration Swale BASIN DATA Proj No.700-19 11 /18/02 infiltswale-#2.xls 1 of4 Drainage Area Des gnation: 'Swale Designation: _ DRAINAGE= Area Infiltration Swale #2 Receiving stream class SA waters Onsite Area = 0.09 acres Onsite Impervious Area = 0.01 acres Offsite Area = 0.00 acres Offsite Impervious Area = 0.00 acres Total Area = 0.09 acres Total Impervious Area = 0.01 acres Percent Impervious = Impervious drainage area (acres)/Drainage area (acres) = 12.2 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 = Drainage area (acres) / Impervious portion of the drainage area (acres) Rv = 0.05 + 0.009(1) Rv = 0.05 + 0.009 * 12.2 = 0.160 (in/in) Volume to be controlled from the design storm event: where: Design rainfall Rv Drainage Area 1.5 (in) 0.160 (in/in) 0.09 (acres) Volume required (cf) = rainfall (in) x Rv (in/in) x Drainaae Area (arse) x 1/12(feet/inches) x 43560 (sf/acre) Vreq'd = 1.5 *.0.160 * 0.09 * 1/12 * 43560 = 78 cubic feet INFILTRATION BASIN - Schueler Method Design Calculations for The Gauntlet Clubhouse Tennis Court Site, High Density Area, Infiltration Swale Determine the volume of the proposed pondlswale: POND GEOMETRY Proj No.700-19 11 /18/02 infiltswale-#2.xis 2of4 Comments Contour Contour Elevation Area (msl) (sf) Incremental Storage (cf) Bottom Elevation 8.25 94 64 8.5 415 154 Storage Elevation 8.75 813 I Total Volume of Pond/Swale = 217 cubic feet volume proposed to volume required from the design storm event: 217 cf > Vreq'd = 78 cf (OK -proposed basin volume is greater than minimum required volume) INFILTRATION BASIN - Schueler Method Design Calculations for The Gauntlet Clubhouse Tennis Court Site, High Density Area, Infiltration Swale Proj No.700-19 11 /18/02 infiltswale-#2.xls 3of4 B) Check pond 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 ] / Sum[A] Description AREA C CA Impervious Area 0.415 0.01 Pervious Area 0.08 -0.3f1 0.024 Sum A = 0.09 Sum CA = 0.034 C ave = 0.034 / 0.09 = 0.379 Determine required discharge from 25 year-24 hour storm event: Qreqd= CavgxlxA Q regd = 0.38 * 0.33 * 0.09 = 0.01 cfs where: I = intensity for 25 year-24 hour storm event from Chart E-6 0,33 in/hr A = drainage area = = 0.09 acres Cavg = weighted coefficient of runoff = 0.38 Check available rate of infiltration provided by proposed swale: where: I = infiltration rate of soil (4 to 12 in/hr per Soils Report) Use: = 6 in/hr A = bottom area of swale = = 1959 sf Qavail = IA = 6 in/hr * 1959 sf * 1 ft/12 in * 1 hr/3600sec = 0.27 cfs ire rate of infiltration with runoff rate from the 25 year storm event: 0.27 cf > Q regd = 0.01 cf (OK -No Discharge for 25 yr-24 hr storm event) INFILTRATION BASIN - Schueler Method Design Calculations for The Gauntlet Clubhouse Tennis Court Site, High Density Area, Infiltration Swale Proj No.700-19 11/18/02 infiltswale-#2.xls 4of4 C) Check the 10 year-10 minute storm event to confirm that basin has capacity without flushing system where: I = intensity for 10 year-10 minute storm event from Chart E-6 = in/hr A = drainage area = = 0.09 acres Cavg = weighted coefficient of runoff = 0.38 Determine. discharge rate from 10 year-10 minute storm event: Q 10-yr = Cavg x I x A Q 10-yr = 0.38 * 6.3 * 0.09 = 0.22 cfs Determine discharge volume from 10 year-10 minute storm event: V 10-Y = Q 10-yr * 10 min. duration ' 60 sec/min. = 129 cf Check available volume of the proposed infiltration basin: V avail = design volume (from geometry table) = 217 cf Compare design volume of infiltration basin to discharge volume from 10 year storm event of 10 minute duration: avail = 217 cfs > V 10-yr = 129 cfs (OK -basin has adequate capacity for 10-yr event without flushing) Compare infiltration system drawdown time to maximum drawdown period of 5 days T = V regd / Q avail * 1 hr/ 3600 sec pT = 78 cf / 0.27 cfs * 1 hr/ 3600 sec = 0.08 hours (OK -.system draws down in less than 5 days) SEDIMENT STORAGE CALCULATIONS DISTURBED AREA #1 CALCULATIONS (30.492 CF)(0.5)(1/12) = 1,270 CF INFILTRATION SWALE #1 DATA: (FOR TEMP. SEDIMENT TRAP) CONTOUR ELEVATION (MSL) CONTOUR AREA (SF) INCREMENTAL STORAGE (CF) BOTTOM EL. 8.25 3502 1040 8.50 4815 1425 STORAGE EL. 8.75 6587 STORAGE PROVIDED > STORAGE REQUIRED 2465 CF > 1270 CF DISTURBED AREA #2 CALCULATIONS (3,920 CF)(0.5)(1/12) = 163 CF INFILTRATION SWALE #2 DATA: (FOR TEMP. SEDIMENT TRAP) CONTOUR ELEVATION (MSL) CONTOUR AREA (SF) INCREMENTAL STORAGE (CF) BOTTOM EL. 8.25 94 54 8.50 415 154 STORAGE EL. 8.75 813 STORAGE PROVIDED STORAGE > REQUIRED 217 CF > 163 CF Erosion Control Specifications Erosion and Sedimentation Control 1.01 General: The contractor shall be responsible for erosion and sedimentation control � rithin the cons action limits; for prevention of sediment laden runoff 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 fully 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 (30) thirty 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: 1. 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. 6. 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: 1. Earth slope protection 2. Diagonal water break diversion berms 3. Diversion channels 4. Preservation of existing vegetation 5. Storm inlet protection 6. Stream crossings 7. Energy dissipators 8. 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 halfway 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 scdiment. 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- made waterway and they shall be stabilized as to not degrade and produce sediment. 1.08 Excavation and Backfill_: Excavation shall be 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. Backfilling 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 performed after the construction 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 permanent 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 permit-- shall be available at the job site at all times. Project Name: GQU? Ae7ro S 710 1p'l41S Gt,-f s -J-�J _ - Location: ar'Un sw,c% DIVISION OF WATER QUALITY INFILTRATION SYSTEM INVESTIGATION 1 • The minimum bore depth: --�L Existing ground elevation: S 75 Proposed Bottom elevation: 8, 25 �,25 -- Add 2' Depth: +2 '75 + 1 25 +2 +2 2. The type of soil: 3. The expected infiltration rate: 60 r 2C-) ` 4. The depth to the Seasonal High Water Table: �a ri%SL j S - 2 ) 1 5. Additional comments:1-aft Xi1 e /()' f - o Signature of Regional Office Personnel: Linda Lewis, DWQ Permit Application No. SGV 2? a Z f / /(P S:IWQSISTORMWATIFORMS\WINVST.FOR Vincent Lewis, Soil Scientist Date / d 3