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Home My WebLink AboutWPO201700036 Calculations WPO VSMP 2017-07-14 1 \,,l' `..-.14°.,i ..fir - r� Stormwater Report Drainage Calculations New Ivy Solid Waste Transfer Station Presented to: S�oo' A AV. 11'*7. kiliGII3ZA COUNTY OF ALBEMARLE Department of Community Development 401 McIntire Road, North Wing Charlottesville, VA 22902-41 26 Presented by: SCS ENGINEERS 2877 Guardian Lane Suite 1-F Virginia Beach, Virginia 23452 (757) 466-3361 July 14, 2017 File No. 02216108.01 Offices Nationwide www.scsengineers.com mei Drainage Calculations New Ivy Transfer Station SCS ENGINEERS YIW Table of Contents Section Page rr► Stormwater Management 1 Drainage Areas 1 Water Quality BMPs 1 Filtering Practices 1 Sand Filter A 2 Sand Filter B 2 Sand Filter C 2 Sand Filter D 2 I. Channels 2 Storm Drains 3 Storm Drain Pipes 3 Trench Drain 3 Drop Inlets 3 Outlet Protection Calculationslit 4 Stormwater Basin 4 Appendices A. Water Quality BMPs B. Sand Filter A C. Sand Filter B D. Sand Filter C E. Sand Filter D F. Channels G. Storm Drains H. Trench Drains 1. Drop Inlets J. Outlet Protection K. Existing Stormwater Basin Um Drainage Calculations New Ivy Transfer Station SCS ENGINEERS STORMWATER MANAGEMENT +r. The post-development stormwater management system is shown on Drawing SW2, Stormwater Management Plan and Drainage Areas. r. Components of the stormwater management system include: • Water Quality BMPs (Sand Filters) • Channels rr • Storm Drains with Trench Drains • Existing Stormwater Basin sr Drainage Areas The drainage areas were delineated in order to find the peak flow hydrographs for a given storm event. The stormwater management system was sized to handle the peak discharge for a 10-year, 24 hour rain event. Drainage areas are shown on Drawing SW2. WATER QUALITY BMPS Filtering Practices To comply with the water quality criteria (9VAC25-870-65), the Virginia Runoff Reduction Method (VRRM)was utilized in order to determine the appropriate best management practices (BMPs) for pollutant removal. The main purpose of the VRRM is to compute the required nutrient load reduction based on hydrologic soil groups and three categories of developed land cover of the site. The three categories of developed land are Forest/Open Space (F/O), Managed 1°"r Turf(MT), and Impervious Cover(IC). The Virginia DEQ Stormwater Design Specification No. 12 Filtering Practices, was chosen as I the method of pollutant removal since filtering methods are more suitable to provide treatment at stormwater hotspots. i,. Under the VRRM, BMPs that are not wet ponds, have some type of vegetative cover,and do not replace an otherwise impervious surface can be treated as Forest/Open Space (F/O). Therefore, a layer of topsoil with grass will be placed on the proposed sand filters and their areas will be considered as Forest/Open Space (F/O). The north portion of the project area contained impervious covers that will be altered during land-disturbing activities, therefore from (9VAC25- 870-63 A 2) for defining redevelopment the site qualifies to use the redevelopment VRRM a• spreadsheet for water quality calculations. The summary of the VRRM redevelopment spreadsheet is provided in Appendix A. Things to note from the summary attached in Appendix A, the total drainage area is 5.29 acres while the treated drainage area is 4.28 acres, the rr remaining 1.01 acres discharges as overland flow out of the project area. Drainage Area A Summary, 14.b Manufactured Treatment Device- Filtering was manually inputted to represent ■. Mil i Drainage Calculations New Ivy Transfer Station SCS ENGINEERS Sand Filter D to act in series with Sand Filter A. This is also true under the Drainage Area B Summary sheet- 14.b Manufactured Treatment Device-Filtering was manually inputted to represent Sand Filter C in series with Sand Filter B. The sand filters were sized to accommodate a specified Treatment Volume. The volume to be treated by the filtering device is a function of the storage depth above the filter and the surface area of the filter as outlined in Equation 12.1 of the VA DEQ Stormwater Design Specification No. 12. The calculation to determine storage depth for each sand filter is provided in Appendix A. Sand Filter A To meet the retreatment requirement for Sand Filter A, a combination of a forebay and level P spreader were used. The forebay was designed to accommodate 25%of the total treatment volume (inclusive), and the level spreader was used to distribute the flow from a one inch storm event evenly over the filter surface. Calculations are provided in Appendix B. Sand Filter B It was determined that a level spreader is sufficient for Sand Filter B, since it is in series with Sand Filter C. Level spreaders were designed using VA DEQ Stormwater Design specifications No. 2 in order to spread channel flow out evenly over the sand filters. The length of the required level spreader needs to be a minimum of 13 ft/cfs of discharge using an intensity of 1 in/hour as outlined in specification No. 2 of the VA DEQ Stormwater Design Specifications. Calculations are provided in Appendix C. Sand Filter C A gravel diaphragm will be used as pretreatment for Sand Filter C since the majority of flow comes from sheet flow off of impervious cover. The remaining flow comes from a trench drain and will have the diaphragm extended to its outlet to disperse the concentrated flow. With the minimal discharge velocities, pea gravel will adequately handle the discharge energy. Sand Filter D Like Sand Filter C, use a gravel diaphragm to pretreat sheet flow from impervious covers. Extend the pea gravel to the outlet of the contributing trench drain to disperse the concentrated flow. With the minimal discharge velocities, pea gravel will adequately handle the discharge energy. CHANNELS Channels are designated as follows: • A18 (Section 1) -A standard VDOT type "Al" paved channel with a depth of 6-inches that discharges into a V-ditch Flexamat® lined channel with geometry of 6:1 and 4:1 side slopes. 2 too Drainage Calculations New Ivy Transfer Station SCS ENGINEERS • Al8 (Section 2) -A V-ditch Flexamat® lined channel with geometry of 3:1 side slopes and a depth of 1 foot. w • Al9- A V-ditch Flexamat® lined channel with geometry of 3:1 side slopes and a depth of 1.5 feet. r • A20 - Grass V-Ditch with a channel geometry of 3:1 side slopes and a depth of 9 inches. Temporary Erosion control matting (VDOT EC-2)will be installed to protect the channel until a good stand of grass is established. • A21 -A standard VDOT type "A 1"paved channel with a depth of 6-inches that discharges into a V-ditch Flexamat® lined channel with geometry of 6:1 and 4:1 side slopes. Each channel was designed to have the capacity to handle a 10-year 24 hour event. Channel linings were designed to minimize scour based on peak velocities for the 10-year 24 hour event. Channel capacity and liner adequacy calculations are provided in Appendix F. NW STORM DRAINS Storm Drain Pipes To account for a variety of structural conditions, various classes of reinforced concrete pipes are to be used in the stormwater management system. A schedule of these pipes can be found on Drawing SW 1. The calculations for determining the required class of reinforced concrete pipe is provided in Appendix G. Trench Drain Two trench drains are located at the building entrance to collect stormwater before it enters the r transfer station. They are sized to handle 0.22 cfs and are recommended to be impact resistant due to heavy traffic loading. The first trench drain will split the flow into sand filters,C and D, while the second trench drain will discharge to the managed turf area on the west side of the site and into Sand Filter D on the east side of the transfer station. Trench drain calculations are provided in Appendix H. Drop Inlets Irr Drop inlets will be used as the outfall structures for the proposed sand filters and drainage areas. In order to calculate the sizing required for drop inlets in the BMP's, Appendix 9c-13 from the to VDOT Drainage Manual was used to decide whether a VDOT standard DI-1 with 50-percent clogging is adequate. A single drop inlet is adequate for use in Sand Filters B, C and D. Due to its larger flow, Sand Filter A requires two DI-1's. Calculations are provided in Appendix I. The .r elevations of the drop inlet structures A4, A9, and A 12 are set at 6 inches above grade, to allow for filtering of the water quality storm. Structure A3 will be set at 0.55 feet above the filtering surface to allow for filtering of the water quality storm event. r 3 f Drainage Calculations New Ivy Transfer Station SCS ENGINEERS A drop inlet will also be used as the inlet for the culvert crossing the proposed north access road to the transfer station. Outlet Protection Calculations Outlet protection was determined using outlet velocities from storm drains. Riprap will be used for the outlet into the existing stormwater basin. Where storm drains discharge into channels, the channels will be lined with Flexamat®. Where storm drains discharge into sand filters,there will be a 3 inch pea gravel layer of outlet protection. Trench drains discharging into open space and sand filters, gravel diaphragms will be used. The calculations for all outlets are attached in Appendix J. STORMWATER BASIN The existing zero discharge stormwater basin was designed to provide irrigation water for the landfill. The stormwater basin will be utilized in the erosion and sediment control plan during construction activities as a sediment basin in lieu of sediment traps. It is adequately sized as a sediment basin. Calculations provided in Appendix K. The storm water basin maintains its capacity to have zero discharge for the 1, 2, 10, and 100-year storm events. Calculations provided in Appendix K. 1 4 it r. is +r. rr APPENDIX A +�. Water Quality BMPs (Sand Filters) Sit MO es 1 SCS ENGINEERS Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108.01 Subject By Date Water Quality Compliance NTJ 3/3/2017 Checked Date Purpose: Determine the size of the BMPs to comply with the water quality criteria of(9VAC25-870-65). Given: 1.Drainage areas are deliniated on Drawing SW2 of the Final Site Design. • 2.Hydrologic Soil Classification taken from Nationa Resources Web Soil Survey updated 2013. Assumptions: 1.The project area contains impervious covers that will be altered in land disturbing activites and qaulifies the area as redevelopment. 2.Sand Filters will be used since the project area is considered a"Hot Spot". 3.The Sand Filter BMPs are in series. 4.The Sand Filter BMPs area contribute to Open Space area in the calculations. 5.The entire site will be classified with Hydrologic Soil Classification of"C". Calculations: Calculations for nutrient removal are provided on the DEQ Virginia Runoff Reduction Method Re-Development Spreadsheet-Version 3.0. Conclusions: The site requires 4 BMPs,where Sand Filter A and D are in series and Sand Filter B and C are in series. Total TP Load Reduction Required(Ib/yr)=2.47 Total TP Load Reduction achieved(Ib/yr)=2.61 t 1 to MI Soil Map—Albemarle County,Virginia 3 14 k 705750 705800 70589) 705900 705950 706000 70 050 Wil 38°1'20"N 38°1'20"N elle A N x r v Q- lA A o "f9 7. • NL k. `. •,y x �a€.= to 0 6 "j t f,r A0. * ka r .- . " l � � .r sy '' 4f 43 J O sr 3 O o. 36B it Y x d p 1•S.N .. ,'... 705950 to 3B°1'S'N 705750 J05800 705850 705900 706000 705050 3 8 — b g Map Scale:1:2460 If printed on A portrait(8.S'x 11")sheet. —_ _.... ,Meters ,Feet N 60 120 — 180 k 200 400 Map p ojection:Web Me Gator Comer onlinale5:WGS84 Edge tl s:1Ji14 7/612016 Zone 17N WGS84 USDA Natural Resources Web Soil Survey Conservation Service National Cooperative Soil Survey Page 1 of 3 o3 1 • OM oo p m O O <i. 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U) G CY .E D -, a s m M c Q ti 0 O w , O (9 3 ,- m w J N d o N o d o c"= o ▪ a J a o E Z` .) • � 3 7, aaO an a, 3 " O c c 5 > i cn O - a a amo a. no a 2. _ o ` 8 O (f) (J) dT m ° Q o m m m a 3 . a v d = u- o m c U 4, m Y . u O > > a m> m Nu a c C a) E _n _ _ O 0 c c m f N aC = Ea to U) c m CO =U 3 0 0 _ii n COCCl)uiU) CO O CO aate :!i m N m o Zqq U oI Soil Map—Albemarle County,Virginia Map Unit Legend _ Albemarle County,Virginia(VA003) Map Unit Symbol ( Map Unit Name Acres in AOI Percent of AOI 1B Abell silt loam,2 to 7 percent 0.0 0.1% slopes SIM 14C Chester loam,7 to 15 percent 1.2 5.3% slopes 19B Cullen loam,2 to 7 percent 8.3 35.9% slopes 20C3 Cullen clay loam,7 to 15 2.0 8.8% percent slopes,severely eroded 20D3 Cullen clay loam,15 to 25 0,0 0.0% percent slopes,severely eroded 368 Hayesville loam,2 to 7 percent 1.6 6.8% slopes 36C Hayesville loam,7 to 15 percent 3.4 15.0% slopes 37C3 Hayesville clay loam,7 to 15 6.0 26.2% percent slopes,severely eroded 37D3 Hayesville clay loam, 15 to 25 0.4 1.9% percent slopes,severely eroded Totals for Area of Interest 23.0 100.0% USDA Natural Resources Web Soil Survey 7/6/2016 Conservation Service National Cooperative Soil Survey Page 3 of 3 I 1992 I Soil name eurftex hydgrp kfact wtdepl wtdeph COTACO CS-FSL C 0.24 1.50 2.50 COTACO FSL C 0.37 1.50 2.50 COTACO L C 0.37 1.50 2.50 I COTACO SIL C 0.37 1.50 2.50 COTACO VARIANT CB-L C 0.24 2.00 3.00 COTACO VARIANT SIL C 0.43 2.00 3.00 IICOURSEY L C 0.32 2.00 3.00 COWEE CH-L 8 0.20 6.00 6.00 COXVILLE FSL D 0.24 0.00 1.50 COXVILLE L D 0.24 0.00 1.50 IICRAIGSVILLE CB-FSL B 0.28 6.00 6.00 CRAIGSVILLE CB-SL B 0.20 6.00 6.00 CRAIGSVILLE CB-SL B 0.28 6.00 6.00 CRAIGSVILLE CBV-L p 0.10 6.00 6.00 IICRAIGSVILLE GR-FSL B 0.17 6.00 6.00 CRAIGSVILLE L B 0.28 6.00 6.00 CRAIGSVILLE SL 8 0.17 6.00 6.00 CRAVEN CL C 0.37 2.00 3.00 IICRAVEN FSL C 0.32 2.00 3.00 CRAVEN L C 0.32 2.00 3.00 CRAVEN SCL C 0.37 2.00 3.00 IICRAVEN SIL c 0.32 2.00 3.00 CREEDMOOR FSL C 0.28 1.50 2.00 CREEDMOOR GR-FSL C 0.28 1.50 2.00 CREEDMOOR GRV-SL C 0.28 1.50 2.00 IICREEDMOOR L C 0.28 1.50 2.00 CREEDMOOR SL C 0.28 1.50 2.00 CREEDMOOR VARIANT FSL C 0.37 0.50 1.50 CREEDMORE FSL C 0.28 1.50 2.00 IICROTON SIL D 0.37 0.00 1.50 CROTON SIL D 0.43 0.00 0.50 CULLEN CL C 0.24 6.00 6.00 CULLEN L C 0.37 6.00 6.00 CULPEPER CL C 0.37 6.00 6.00 II CULPEPER FSL C 0.37 6.00 6.00 CULPEPER L C 0.37 6.00 6.00 IIDALEVILLE L D 0.32 0.00 1.00 DALEVILLE SIL D 0.32 0.00 1.00 DANDRIDGE SH-SICL D 0.17 6.00 6.00 DAVIDSON C B 0.28 6.00 6.00 IIDAVIDSON CL 8 0.24 6.00 6.00 DAVIDSON CL B 0.28 6.00 6.00 DAVIDSON CL B 0.37 6.00 6.00 DAVIDSON ST-CL B 0.20 6.00 6.00 I DAWHOO VARIANT FSL 0.17 DECATUR CL B 0.32 6.00 6.00 DEKALB CB-FSL C 0.17 6.00 6.00 I DEKALB C8-L C 0.17 6.00 6.00 DEKALB CB-SL C 0.17 6.00 6.00 DEKALB CN-FSL C 0.17 6.00 6.00 DEKALB CN-L C 0.17 6.00 6.00 IIDEKALB CN-SL C 0.17 6.00 6.00 DEKALB FSL C 0.24 6.00 6.00 DEKALB RB-FSL C 0.17 6.00 6.00 VI - 58 I ' I US a. 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I. % .:4 •it \ . $ • To 0 w i � rr r■ rw ✓r r ®,,, APPENDIX B Sand Filter A �r. r.. SCS ENGINEERS Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108.00 Subject By Date Sand Filter Drop Inlet Rim Elevations NTJ 3/9/2017 Checked Date Sheet 1 of 1 Purpose: Determine the Rim Elevation for drop inlets for Sand Filter A. Given: VA DEQ Stormwater Design Specification No.12 Equation 12.1. Drainage Area contributing to Filter,from Drawing SW2,A= 132890.338 sq.ft Area of the Filter Surface from drawing SW2,Af= 2899.02 sq.ft Runoff Coefficient(From VRRM),Rv= 0.38 VA DEQ Stormwater Design Specification No.12 Equation 12.2. Assumptions: VA DEQ Stormwater Design Specification NO.12 Equation 12.1 Af=(TV)(df)/((K)(hf+df)(tf)) where: Af= Surface Area of Filter Filter Media depth,df: 2 ft Coefficient of permeability(partially clogged sand),K: 3.5 ft/day Allowable Drawdown time,tf: 1.67 days hf= Depth of water above filter bed Storage volume of Forebay= 1060 cu.Ft. Calculations: Treatment Volume,TV: =[1.0(Rv)(A)]/(12) 4208.19 cu.Ft Adjust equation 12.1 to solve forAverage Height of Water above Filter bed,hf: hf=(TV)(df)/((Af*tf*K))-df -1.50 ft Using Equation 12.2,Volume of Storage,Vs: =.75*TV 3156.15 cu.Ft Required rim elevation,Hr= =Vs-Forebay Volume 2096.15 cu.Ft. using Storage Curve from Hydragraphs,Hr= 0.55 ft Conclusions: From Equation 12.1,the average depth of water above the filter bed is-1.50 ft. This means all of the runoff will be stored bellow the filter bed surface. From equation 12.2,the storage volume required in order to capture the volume from high intensity storms prior to filtration and avoid premature bypass is 2096.15 cu. Ft.including the storage volume of the forebay.The required rim elevation of the drop inlet is 0.55 ft above filter bed. For design set the rim at 0.55 ft or 7 inches above filter bed. rr Pond Report es Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v10.5 Friday,03/10/2017 Pond No.1 - Sand Filter A Pond Data ss Contours-User-defined contour areas.Conic method used for volume calculation.Begining Elevation=704.00 ft Stage/Storage Table Stage(ft) Elevation(ft) Contour area(sqft) Incr.Storage(cuff) Total storage(cult) OS 0.00 704.00 2,899 0 0 2.00 706.00 4,841 7,657 7,657 Culvert/Orifice Structures Weir Structures In [A] [B] [C] [PrfRsr] [A] [B] [C] [D] Rise(In) = 0.00 0.00 0.00 0.00 Crest Len(ft) = 0.00 0.00 0.00 0.00 list Span(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 3.33 3.33 3.33 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 no Slope(%) = 0.00 0.00 0.00 n/a N-Value = .013 .013 .013 n/a Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfll.(in/hr) = 0.000(by Contour) Multi-Stage = n/a No No No TW Elev.(ft) = 0.00 we Note:Culvert/Orifice outflows are analyzed under Wet(ic)and outlet(oc)control. Weir risers checked for orifice conditions(ic)and submergence(5). ale Stage(ft) Stage/Storage Elev(ft) tkr 2.00 706.00 1.80 705.80 in 1.60 705.60 in 1.40705.40 1.20 705.20 tr 1.00 705.00 we0.80 704.80 .0 S 0.60 , 704.60 in Nit, 0.40 704.40 fee 0.20 704.20 0.00 704.00 0 800 1,600 2,400 3,200 4,000 4,800 5,600 6,400 7,200 8,000 MO Storage Storage(cuft) 209(7 Ck), t. err 1 SCS ENGINEERS Client Project Job No, Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108 01 Subject By Date Required Foreay size NTJ 1/30/2017 Checked Date Sheet 1 of 2 Purpose. Determine the required storage capacity of the forebay Given: Total Treatment volume From sand filter Dl rim elevations calculation,Tv: 4208.19 cu.Ft. Assumptions: Design specification No.12 sediment chanmbers must be sized to accommodate at least 25%of the total treatment volume Calculations: Total storage volume of pretreatment,Tp: 1052.0475 cu.Ft 39.0 cu.Yds. =TV'.25 Forbay Hydraflow Hydrographs Extension Elevation to achieve storage volume,EL= 707.25 = 1060 cu.Ft. Conclusions: Sand Filter A Forebay needs 39.0 cu.Yards of storage. Pond Report �. Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v10.5 Wednesday,01 /25/2017 Pond No. 1 - Forebay Pond Data ,- Contours-User-defined contour areas.Conic method used for volume calculation.Begining Elevation=706.00 ft Stage/Storage Table Stage(ft) Elevation(ft) Contour area(sqft) Incr.Storage(cuft) Total storage(cuft) tall 0.00 706.00 600 0 0 1.00 707.00 1,000 791 791 1.25 707.25 1,152 269 1,060 1.50 707.50 1,265 302 1,362 I 2.00 708.00 1,500 690 2,053 2.50 708.50 1,767 816 2,868 2.75 708.75 1,905 459 3,327 3.00 709.00 2,000 488 3.815 Culvert/Orifice Structures Weir Structures [A] [B] [C] [PrfRsr] [A] [B] [C] [D] ,. Rise(in) = 24.00 Inactive Inactive 6.00 Crest Len(ft) = 6.28 0.00 0.00 0.00 Span(in) = 24.00 0.00 0.00 6.00 Crest El.(ft) = 708.00 0.00 0.00 0.00 No.Barrels = 1 0 0 1 Weir Coeff. = 3.33 3.33 3.33 3.33 Invert El.(ft) = 706.00 0.00 0.00 707.25 Weir Type = 1 --- --- -- .M Length(ft) = 65.00 0.00 0.00 0.75 Multi-Stage = Yes No No No Slope(%) = 3.17 0.00 0.00 n/a N-Value = .024 .013 .013 n/a Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(in/hr) = 0.000(by Contour) .. Multi-Stage = n/a No No Yes TW Elev.(ft) = 0.00 Note.Culvert/Orifice outflows are analyzed under inlet(ic)and outlet(oc)control. Weir risers checked for orifice conditions(ic)and submergence(s). Stage/Storage/Discharge Table Stage Storage Elevation Clv A Clv B Clv C PrfRsr Wr A Wr B Wr C Wr D Exfil User Total ft tuft ft cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs 0.00 0 706.00 0.00 - --- 0.00 0.00 -- --- -- -- -- 0.000 1.00 791 707.00 0.00 -- --- 0.00 0.00 -- --- --- --- -- 0.000 - 1.25 1,060 707.25 0.00 --- -- 0.00 0.00 --- --- --- --- --- 0.000 1.50 1,362 707.50 0.11 ic - -- 0.11 0.00 -- --- ---- -- -- 0.105 2.00 2,053 708.00 0.56 ic -- --- 0.55 0.00 -- --- --- --- --- 0.546 2.50 2,868 708.50 8.49 ic -- -- 1.09 7.39 -- --- -- --- 8.486 2.75 3,327 708.75 14.27 ic - -- 0.69 13.58 --- -- -- --- --- 14.27 ON 3.00 3,815 709.00 18.33 ic - --- 0.32 18.01 s --- --- --- -- --- 18.33 i I I I Pond Report I Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v10.5 Wednesday,01/25/2017 Pond No. 1 - Forebay Pond Data I Contours-User-defined contour areas.Conic method used for volume calculation.Begining Elevation=706.00 ft Stage/Storage Table Stage(ft) Elevation(ft) Contour area(sqft) Incr.Storage(cuft) Total storage(cuft) 0.00 706.00 600 0 0 1.00 707.00 1.000 791 791 1.25 707.25 1,152 269 1,060 I 1.50 707.50 1,265 302 1,362 2.00 708.00 1,500 690 2,053 2.50 708.50 1,767 816 2,868 2.75 708.75 1,905 459 3,327 I 3.00 709.00 2,000 488 3,815 Culvert/Orifice Structures Weir Structures [A] [B] [C] [PrfRsr] [A] [B] [C] [D] I Rise(in) = 24.00 Inactive Inactive 6.00 Crest Len(ft) = 6.28 0.00 0.00 0.00 Span(in) = 24.00 0.00 0.00 6.00 Crest El.(ft) = 708.00 0.00 0.00 0.00 No.Barrels = 1 0 0 1 Weir Coeff. = 3.33 3.33 3.33 3.33 I Invert El.(ft) = 706.00 0.00 0.00 707.25 Weir Type = 1 -- --- -- Length(ft) = 65.00 0.00 0.00 0.75 Multi-Stage = Yes No No No Slope(%) = 3.17 0.00 0.00 n/a N-Value = .024 .013 .013 n/a Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(inlhr) = 0.000(by Contour) I Multi-Stage = n/a No No Yes TW Elev.(ft) = 0.00 Note Culvert/Orifice outflows are analyzed under inlet(id)and outlet(oc)control Weir risers checked for orifice conditions(ic)and submergence(s) I Stage(ft) Stage/Discharge Elev(ft) I 3.00 - 709.00 i 2.00 - 708.00sok NW 1.00 707.00 um („7....„...„,_________________ so 0.00 706.00 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00 am Discharge(cfs) Total Q Culv A Prf Riser Struct HG Weir A In 4. 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V M N 0 m U i I I !_.. 1 1 I 1 1.__1 1 I I I I I 1i co a) Client Project Job No. ' Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108.01 Subject By Date BMP Level Spreader Length NTJ 1/20/2017 Checked Date Sheet 1 of 1 Purpose: Determine the Level Spreader length required for Sand Filter A , Given: Total Area,A: 3.06 acre Impervious area,Ap: 0.56 acre Good stand grass area,Ag: 2.50 acre Assumptions Rainfall Intensity,is 1.00 in/hr Use 1 in/hour as instructed by DEQ design specification No.2 Use 13 ft level spreader length per 1 cfs of discharge from DEQ Design Specification No.2. C value for impervious area,Cp: 0.90 C value for grass area,Cg: 0.35 Calculations: Weighted Ave.Runoff Coefficent,C: , =((Ap*Cp)+(Ag*Cg))/A 0.451 Peak Flow,Qp: Qp=C*i*A 1.38 cfs Minimum Level Spreader Length,L: L=13*Qp 17.93 ft Conclusions Use a level spreader with a minimum length of 18 ft. 1 1 1 I 1 SCS ENGINEERS Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Trasnfer station 02216108.01 Subject By Date Erosion Control Measures for Sand Filter Surface NTJ 3/912017 Checked Date Sheet 1 of 1 Purpose: Receiving areas downstream of the discharging pipe in Sand Filter A to handle the force of flow. Given: 1.10 year,24 hour storm event used to determine peak flow.See Area A storm drain calculations.Qp=9 cfs. Assumptions: 1.Channel Lining Velocity Ranges: Velocity Lining 0-3 ft/sec Grass 0-4 ft/sec EC-2(VDOT Matting) 4-10 ft/sec EC-3(VDOT Matting) 10+ft/sec Flexamat® Calculations: See attached express calculations,for Velocities. Velocity do 3.48 ft/sec Conclusions: The velocity discharging into Sand Filter A is 3.48 ft/sec peagravel layer is adequate to handle discharge velocity. OW 1 1 I I .inning's n Values Page 4 of 5 Subdrain 0.017 0.019 0.021 Stormdrain 0.021 0.024 0.030 I 6. Cement: Neat Surface 0.010 0.011 0.013 Mortar 0.011 0.013 0.015 I 7. Concrete: Culvert, straight and free of debris 0.010 0.011 0.013 Culvert with bends, connections, and some 0.011 ;t) „g 0.014 1 debris Finished - 0.011 0.012 0.014 Sewer with manholes, inlet, etc., straight 0.013 0.015 0.017 Unfinished, steel form 0.012 0.013 0.014 Unfinished, smooth wood form 0.012 0.014 0.016 Unfinished, rough wood form 0.015 0.017 0.020 _ -8. Wood: - Stave 0.010 0.012 0.014 Laminated. treated 0.015 0.017 0.020 _9. Clay: T I Common drainage the 0.011 0.013 0.017 Vitrified sewer 0.011 0.014 0.017 1 _ Vitrified sewer with manholes, inlet, etc. 0.013 0.015 0.017 Vitrified Subdrain with open joint 0.014 0.016 0.018 10. Brickwork: Glazed 0.011 0.013 0.015 Lined with cement mortar 0.012 0.015 0.017 Sanitary sewers coated with sewage slime 0,012 0.013 0.016 with bends and connections I Paved invert, sewer, smooth bottom 0.016 0.019 0.020 Rubble masonry, cemented 0.018 0.025 0.030 's n for Corrugated Metal Pipe (AISI, 1980). ' Mannin g g Type of Pipe, Diameter and Corrugation Dimension_ n 1. Annular 2.67 x 1/2 inch (all diameters) 0.024 ' 2. Helical 1.50 x 1/4 inch 8" diameter 0.012 10"diameter 0.014 z 3. Helical 2.67 x 1/2 inch 12" diameter 0.011 18"diameter 0.014 24" diameter 0.016 36" diameter 0.019 48"diameter 0.020 ---- ----- 60"diameter 0.021 4. Annular 3x1 inch (all diameters) 0.027 5. Helical 3x1 inch , 48" diameter 0.023 54" diameter 0.023 60"diameter _ 0.024 ' 66"diameter 0.025 irttn://wwwfclnrctPali/Genwatar/RYZ/hPl„/R L7.,,a,.,.,1:.. Dec /TR..._._:_- - m_i_,__ +. , I Culvert Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk,Inc. Friday,Mar 10 2017 .. A14 Culvert Invert Elev Dn (ft) = 704.00 Calculations Pipe Length (ft) = 65.00 Qmin (cfs) = 9.00 Slope (%) = 3.17 Qmax (cfs) = 9.00 Invert Elev Up (ft) = 706.06 Tailwater Elev (ft) _ (dc+D)/2 Rise (in) = 24.0 Shape = Circular Highlighted Span (in) = 24.0 Qtotal (cfs) = 9.00 No. Barrels = 1 Qpipe (cfs) = 9.00 n-Value = 0.013 Qovertop (cfs) = 0.00 Culvert Type = Circular Concrete Veloc Dn (ft/s) = 3.48 Culvert Entrance = Square edge w/headwall (C) Veloc Up (ft/s) = 5.26 Coeff. K,M,c,Y,k = 0.0098, 2, 0.0398, 0.67, 0.5 HGL Dn (ft) = 705.54 HGL Up (ft) = 707.13 Embankment Hw Elev (ft) = 707.61 - Top Elevation (ft) = 709.00 Hw/D (ft) = 0.77 Top Width (ft) = 0.00 Flow Regime = Inlet Control Crest Width (ft) = 0.00 E4r OS slime.* 71,706846(10 710.00 II U...,.. 1117.94 708.00 ''''�' 1.94 ✓ 707 W ..._.-_ 091 70000_ .008 464 705 LID III .1.08 704.00 - IIIIIIIIIIIII 11111 7.06 OW 11111111111111111111 76'.00 .3.08 0 6 10 16 20 25 30 35 40 46 60 65 80 6S 70 76 00 K Coml.GWvart HGL Em)rnk Reach Rt! Oil OW Oni WW OW 1 1 1 APPENDIX C Sand Filter B ' I I I 1 I iw ,, SCS ENGINEERS Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108.00 Subject By Date Sand Filter Drop Inlet Rim Elevations NTJ 3/9/2017 Checked Date Sheet 1 of 1 Purpose: Determine the Rim Elevation for drop inlets for Sand Filter B. fw Given: VA DEQ Stormwater Design Specification No.12 Equation 12.1. Drainage Area contributing to Filter,from Drawing SW2,A= 40295.66 sq.ft Area of the Filter Surface from drawing SW2,Af= 2161.899 sq.ft Runoff Coefficient(From VRRM),Rv= 0.38 VA DEQ Stormwater Design Specification No.12 Equation 12.2. Assumptions: 1.VA DEQ Stormwater Design Specification NO.12 Equation 12.1. Af=(TV)(df)/((K)(hf+df)(tf)) Sir where: Af= Surface Area of Filter Filter Media depth,df: 2 ft Coefficient of permeability(partially clogged sand),K: 3.5 ft/day Allowable Drawdown time,tf: 1.67 days hf= Depth of water above filter bed 2.When calculating rim elevation assume sand filter has vertical side slopes. r Calculations: Treatment Volume,TV: =[1.0(Rv)(A)]/(12) 1276.03 cu.Ft Adjust equation 12.1 to solve forAverage Height of Water above Filter bed,hf: hf=(TV)(df)/((Af*tf*K))-df -1.80 ft Using Equation 12.2,Volume of Storage,Vs: =.75*TV 957.02 cu.Ft MI Required rim elevation,Hr= =Vs/Af 0.44 Conclusions: From Equation 12.1,the average depth of water above the filter bed is-1.8 ft. This means all of the runoff will be stored bellow the filter bed surface. From equation 12.2,the required storage volume required in order to capture the volume from high intensity storms prior to filtration and avoid premature bypass is 957.02 cu.Ft. The required rim elevation of the drop inlet is 0.44 ft above filter bed. For design set the rim at 0.50 ft. rr ea irw Ole err I Client Project Job No, Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108.01 Subject By Date BMP Level Spreader Length NTJ 1/20/2017 Checked Date Sheet 1 of 1 Purpose Determine the Level Spreader length required for Sand Filter B. I Given: Total Area,A: 1.22 acre Impervious area,Ap: 0.68 acre Good stand grass area,Ag: 0.54 acre Assumotions: Rainfall Intensity,is 1.00 in/hr Use 1 in/hour as instructed by DEQ design specification No.2 Use 13 ft level spreader length per 1 cfs of discharge from DEQ Design Specification No.2. C value for impervious area,Cp: 0.90 C value for grass area,Cg: 0.35 Calculations: Weighted Ave.Runoff Coefficent,C: =((Ap*Cp)+(Ag*Cg))/A 0.657 Peak Flow,Op: Qp=C*i*A 0.80 cfs Minimum Level Spreader Length,L: L=13*Qp 10.41 ft Conclusions' Use a level spreader with a minimum length of 18 ft. I I I rr • • wr APPENDIX D Sand Filter C r�r OP .0 S. ■ SCS ENGINEERS Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108.00 Subject By Date Sand Filter Drop Inlet Rim Elevations NTJ 3/9/2017 Checked Date Sheet 1 of 1 Purpose: Determine the Rim Elevation for drop inlets for Sand Filter C. I Given: VA DEQ Stormwater Design Specification No.12 Equation 12.1. Drainage Area contributing to Filter,from Drawing SW2,A= 12846.95 sq.ft Area of the Filter Surface from drawing SW2,Af= 1574.851 sq.ft Runoff Coefficient(From VRRM),Rv= 0.38 VA DEQ Stormwater Design Specification No.12 Equation 12.2. Assumptions: 1.VA DEQ Stormwater Design Specification NO.12 Equation 12.1. Af=(TV)(df)/((K)(hf+df)(tf)) where: Af= Surface Area of Filter Filter Media depth,df: 2 ft Coefficient of permeability(partially clogged sand),K: 3.5 ft/day Allowable Drawdown time,tf: 1.67 days hf= Depth of water above filter bed 2.When calculating rim elevation assume sand filter has vertical side slopes. Calculations: Treatment Volume,TV: =[1.0(Rv)(A))/(12) 406.82 cu.Ft Adjust equation 12.1 to solve forAverage Height of Water above Filter bed,hf: hf=(TV)(df)/((Af*tf*K))-df -1.91 ft Using Equation 12.2,Volume of Storage,Vs: =.75*TV 305.12 cu.Ft Required rim elevation,Hr= =Vs/Af 0.19 Conclusions: From Equation 12.1,the average depth of water above the filter bed is-1.91 ft. This means all of the runoff will be stored bellow the filter bed surface. From equation 12.2,the required storage volume required in order to capture the volume from high intensity storms prior to filtration and avoid premature bypass is 305.12 cu.Ft. The required rim elevation of the drop inlet is 0.19 ft above filter bed. For design set the rim at 0.50 ft. I um err APPENDIX E Sand Filter D flo it 911 w aim r SCS ENGINEERS Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108.00 11 Subject By Date Sand Filter Drop Inlet Rim Elevations NTJ 3/9/2017 Checked Date Sheet 1 of 1 Purpose: Determine the Rim Elevation for drop inlets for Sand Filter D. Given: VA DEQ Stormwater Design Specification No.12 Equation 12.1. Drainage Area contributing to Filter,from Drawing SW2,A= 10460.64 sq.ft Area of the Filter Surface from drawing SW2,Af= 1107.194 sq.ft Runoff Coefficient(From VRRM),Rv= 0.38 VA DEQ Stormwater Design Specification No.12 Equation 12.2. Assumptions: 1.VA DEQ Stormwater Design Specification NO.12 Equation 12.1. Af=(TV)(df)/((K)(hf+df)(tf)) where: Af= Surface Area of Filter Filter Media depth,df: 2 ft Coefficient of permeability(partially clogged sand),K: 3.5 ft/day Allowable Drawdown time,tf: 1.67 days hf= Depth of water above filter bed 2.When calculating rim elevation assume sand filter has vertical side slopes. Calculations: Treatment Volume,TV: =[1.0(Rv)(A))/(12) 331.25 cu.Ft Adjust equation 12.1 to solve forAverage Height of Water above Filter bed,hf: hf=(TV)(df)/((Af*tf*K))-df -1.90 ft Using Equation 12.2,Volume of Storage,Vs: =.75*TV 248.44 cu.Ft Required rim elevation,Hr= =Vs/Af 0.22 Conclusions: From Equation 12.1,the average depth of water above the filter bed is-1.90 ft. This means all of the runoff will be stored bellow the filter bed surface. From equation 12.2,the required storage volume required in order to capture the volume from high intensity storms prior to filtration and avoid premature bypass is 248.44 cu.Ft. The required rim elevation of the drop inlet is 0.22 ft above filter bed. For design set the rim at 0.50 ft. I I 1 Mr aa r. rr w APPENDIX F Channels as r. la w as mai se 1 SCS ENGINEERS Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Startion 02216108.01 Subject By Date Channel A18 NTJ/DCC 7/14/2017 Checked Date Sheet 1 of 1 AST 7/14/2017 Purpose: Channel geometry,and lining adequacy for channel A18. Given: 1.Channel Geometry,V-ditch 1 foot depth,3:1 side slopes: • 2.Flow from Area A peak flow calculations, Qp= 9 cfs 3.Average slope of channel,S= 5 Assumptions: 1.mannings number= 0.035 2.Channel Lining Velocity Ranges Velocity Lining 0-3 ft/sec Grass 0-4 ft/sec EC-2 VDOT matting 4-10 ft/sec EC-3 VDOT matting 10+ft/sec Flexamat® Calculations: See attached Hydraflow express calculations: Velocity= 4.81 ft/sec Conclusions: The channel can adequatly handle the peak flow of 9.0 cfs,and Flexamat®should be used as the lining. I I 68 Precipitation Frequency Data Server Page 1 of 4 NOAA Atlas 14,Volume 2,Version 3 Location name:Charlottesville,Virginia,USA* Latitude:38.0253°,Longitude:-78.6538° Elevation:662.27 ft** ims •source:ESRI Maps ••source:USGS POINT PRECIPITATION FREQUENCY ESTIMATES G.M.Bonnin,D Martin,B.Lin,T.Parzybok,M_Yekta,and D.Riley la NOAA,National Weather Service,Silver Spring,Maryland PF tabular i PF graphical(Marr& aerials sr PF tabular IPDS-based point precipitation frequency estimates with 90%confidence intervals(in inches/hour)1 Average recurrence interval(years) illDuratio 1 1 2 5 10 25 ) 50 II 100 ) 200 N 500 I) 1000 5-min 4.12 4.92 6.80 8.63 7.37 8.02 8.63 9.20 9.90 10.5 (3.72-4.57) (4.45-5.45) (5.23.6.41) (5.88-7.21) (6.60-8.11) (7.15-8.83) (7.64.9.52) (8.09-10.2) (8.60-11-0) (9.00-11.7) 10 min 3.29 3.94 4.64 . 6.87 6.38 6.86 7.30 7.83 8.24 (2.98-3.65) (3.56-4.36) (4.19-5.13) (4.70-5.76) (5.26.6.47) (5.69-7.03) (6.08.7.56) (6.41-8.06) (6.80-8.69) (7.09-9.19) ill. 15-min 2.74 3.30 3.92 4.40 4.96 5.39 6.78 6.14 6.67 6.90 (2.48.3.04) (2.99-3.65) (3.54432) (3 97-C86) (4.45.5.46) (4.80.5.94) (5.12.6.37) (5.40-6.78) _ (5.71-7.29) (5.93-7.69) 30 min 1.88 2.28 2.78 3.19 3.67 4.06 I 4.42 4.78 6.23 5.69 (1.70-2.08) (2.06-2.52) (2.51-3.07) (2.87-3.52) (3.29-4.05) (3.62-4.47) (3.92.4.88) (4.20-5.28) (4.54-5.80) (4.80-6.23) 60-min 1.17 1.43 1.78 2.08 2.45 2.75 3.06 3.36 3.75 4.08 M (1.06-1.30) (1.29-1.58) (1.61-1.97) (1.87-2.29) (2.19-2.70) (2.45-3.03) (2.70-3.36) (2.95-3.70) (3.26-4.16) (3.51-4.55) 0.700 0.852 1.07 1.26 1.50 1.70 1.91 2.12 2.42 2.67 'i 2-hr (0.622-0.792)(0.756-0.961) (0.948-1.20) (1.12-1.41) (1.32-1.68) (1.49-1.91) (1.66-2.14) (1.83-2.38) (2.06-2.73) (2.25-3.02) 3-hr 0.611 0.621 0.778 0.914 1.09 1.24 139 1.55 1.77 1.98 (0.454-0.582)(0.549-0.705)(0.887-0.884) (0.805-1.04) (0.956.1.23) (1.08-1.40) (1.21-1.58) (1.33-1.76) (1.50.2.02) (1.64-2.24) MN 0.331 0.401 0.498 0.687 0.705 0.809 0.918 1.04 1.20 1.36 6-hr (0.296-0.374)(0.357-0A52)(0.442.0.561)(0.518-0.660)(0.619.0.793)(0.704.0.908)•(0.791.1.03) (0.882-1.17) (1.01-1.36) (1.12-1.53) 12-hr 0.209 0.252 0.316 0.372 0.453 0.603 0.689 0.817 0.932 (0.186-0.238)(0.224-0.288)(0.278.0.358)((0.328-0.423)(0.396-0514 r • (0.514.0.684 (0370-.782)(0.671.0.931) (0.753.1.07) MS 24-hr 0.127 0.154 0.196 0.231 0.284 r 0.378 0433 0314 0.583 (0.114-0.142)(0.138.0.172)(0.176-0.219) 07.0258)(0.252-0.316 0.289-0.365)(0.330.0.420)(0.374-0.479)(0.436.0.570) (0.488.0.647)€ 2-day 0.076 0.091 0.115 0.135 0.164 0.188 0.215 0.243 0.285 0.320 (0.067-0.083)(0.081-0.101)(0.103-0.128)(0.121-0.151)I(0.146-0.183 10.166-0.209)(0.188.0.239 (0.211-0.271)(0.244-0.318)(0.271-0.358) 3-day 0.053 0.064 0.082 0.096 0.116 0.133 0.162 0.172 0.201 0.226 (0.048-0.059)(0.058-0.071)(0.074.0.090)(0.086.0.106)(0.104-0.128)(0.119-0.147)(0.134.0.168)(0.151-0.190)(0.174-0.223)(0.193-0.251) lita 4-day 0.042 0.051 0.065 0.076 0.092 0.106 0.120 0.136 0.159 0.178 (0.0394.047)(0.047-0.056)(0.059.0.072)(0.089.0.084);(0.083-0.101)(0.096.0.116)(0.107-0.132)(0.120-0.150)(0.139-0.175)(0.154-0.197) 7-day 0.028 0.034 0.042 0.049 0.059 0.067 0.076 0.085 0.098 0.109 (0.026-0.031)(1031-0.037)(0.039-0.046)(0.045.0.053)(0.053.0.064) 0.060.0.073) 0.066-0.083)(0.075-0.093)(0.086-0.108)(0.095-0.120) N 10-day 0.022 0.027 0.033 0.038 0.046 0.061 0.057 0.063 0.072 0.079 (0.020-0.024)(0.025-0.029)(0.030-0.036)(0.035-0.041)40.041-0.049} 0.046.0.055) 0.051-0.061)(0.057-0.068)(0.064.0.078)(0.070-0.086) 20-day 0.015 0.017 0.021 0.024 0.028 0.031 0.034 0.037 0.041 0.044 (0.014-0.016)(0.016-0.019)(0.020-0.023)(0.022-0.026)(0.028.0.030)(1028.0.033)(0.031.0.036)(0.034-0.040)(0.037-0.044)(0.040.0.048) 0.012 0.014 0.017 0.019 0.021 0.023 0.026 0.027 0.029 0.031 NO 30-day (0.011-0.013)(0.013.0.015)(0.016-0.018)(0.017-0.020)(0.020.0.023)(0.022-0.025)(0.023.0.027)(0.025-0.029)(0.027-0.031)(0.029-0.033) 45-day 0.010 0.012 0.014 0.015 0.017 0.018 0.020 ` 0.021 0.023 0.024 {0.009.0.011 0.011-0.012 (0.013-0,015)(0.014-0.016)(0.016-0.018)(0.017.0.020)I(0.018-0.021)(0.020.0.022)'(0.021-0.024)(1022-0.026) 60-day 0.009 0.010 0.012 0.013 0.014 0.016 0.017 0.018 0.019 0.020 0.008.0.009 (0.010-0.011)(0.011-0.013)(0.012-0.014)(0.014.0.015)(0.015-0.016)(0.018.0.018)(0.016-0.019)(0.018.0.020)(0.018.0.021) Ss Precipitation frequency(PF)estimates in this table are based on frequency analysis of partial duration series(PDS). Numbers in parenthesis are PF estimates at lower and upper bounds of the 90%confidence interval.The probability that precipitation frequency estimates (for a given duration and average recurrence interval)will be greater than the upper bound(or less than the lower bound)is 5%.Estimates al upper bounds are not checked against probable maximum precipitation(PMP)estimates and may be higher than currently valid PMP values. SS Please refer to NOAA Atlas 14 document for more information. Back to Too ill IN e, http://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage-html?1at=3 8.0253&lon=-78.6538&dat... 11/21/2016 Os I 6.4—Design Concepts i The Rational Method Formula is expressed as follows: Q= CfCiA (6.4) Where: I Q = Maximum rate of runoff, cubic feet per second (cfs) Cf = Saturation factor C = Runoff coefficient representing a ratio of runoff to rainfall (dimensionless) i = Average rainfall intensity for a duration equal to the time of concentration for a selected return period, inches per hour(in/hr) A = Drainage area contributing to the point of study, acres (ac) is not Note that conversion to consistent unitsrequired as 1 acre-inch per hour I approximately equals 1 cubic foot/second. 6.4.4.1.5 Infrequent Storm The coefficients given in Appendix 6E-1 are for storms with less than a 10-year recurrence interval. Less frequent, higher intensity storms will require modification of the coefficient because infiltration and other losses have a proportionally smaller effect on runoff (Wright-McLaughlin 1969). The adjustment of the Rational Method for use with larger storms can be made by multiplying the right side of the Rational Formula by a saturation factor, Cf. The product of Cf and C should not NM 1.0. Table 6-2 lists the saturation factors for the Rational Method. Table 6-2. Saturation Factors For Rational Formula I Recurrence Interval (Years) Mill 2, 5, and 10 4 1.0 M, 25 1.1 50 1.2 100 1.25 Note: Cf multiplied by C should not 1.0 6.44.1.6 Time of Concentration The time of concentration is the time required for water to flow from the hydraulically most remote point in the drainage area to the point of study. Use of the rational formula requires the time of concentration (tc)for each design point within the drainage basin. The duration of rainfall is then set equal to the time of concentration and is used to estimate the design average rainfall intensity (i) by using the B, D, & E factors in the procedure described in Appendix 6C-1. A table showing the B, D, & E factors for Virginia counties and larger cities is presented in Appendix 6C-2. I * Rev 4/10 to VDOT Drainage Manual Chapter 6 Hydrology 6.16 of 57 1992 TABLE 5-2 VALUES OF RUNOFF COEFFICIENT (C) FOR RATIONAL FORMULA Land Use C Land Use C Business: Lawns: Downtown areas 0.70-0.95 Sandy soil, flat, 2% 0.05-0.10 Neighborhood areas 0.50-0.70 Sandy soil, average, 2-7% 0.10-0.15 Sandy soil, steep, 7% 0.15-0.20 Heavy soil, flat, 2% 0.13-0.17 Heavy soil, average, 2-7% 0.18-0.22 Heavy soil, steep, 7% 0.25-0.35 k.)S� o•3 Residential: Agricultural land: Single-family areas 030-0.50 Bare packed soil Multi units, detached 0.40-0.60 * Smooth 0.30-0.60 Multi units, attached 0.60-0.75 * Rough 0.20-0.50 Suburban 0.25-0.40 Cultivated rows * Heavy soil, no crop 0.30-0.60 * Heavy soil, with crop 0.20-0.50 * Sandy soil, no crop 0.20-0.40 * Sandy soil, with crop 0.10-0.25 Pasture * Heavy soil 0.15-0.45 * Sandy soil 0.05-0.25 Woodlands 0.05-0.25 Industrial: Streets: Light areas 0.50-0.80 Asphaltic 0.70-0.95 `Ce Heavy areas 0.60-0.90 Concrete 0.80-0.95 (1)'10 Brick 0.70-0.85 Parks, cemeteries 0.10-0.25 Unimproved areas 0.10-0.30 Playgrounds 0.20-0.35 Drives and walks 0.75-0.85 Railroad yard areas 0.20-0.40 Roofs 0.75-0.95 Note: The designer must use judgement to select the appropriate "C" value within the ® range. Generally, larger areas with permeable soils, flat slopes and dense vegetation should have the lowest C values. Smaller areas with dense soils, moderate to steep slopes, and sparse vegetation should be assigned the highest C values. Source: American Society of Civil Engineers I V - 29 Manning's n Values Page 1 of 5 I 1 Show Manning's n Values 4•1 021•0 111 Reference tables for Manning's n values for Channels, Closed Conduits Flowing Partially Full, and Corrugated Metal Pipes. USE 0.v35 -' Att.... is Fat ci 0,4Ats, owl. "IR tpj--Rf4? Manning's n for Channels (Chow, 1959). `r I Type of Channel and Description Minimum Normal Maximum Natural streams- minor streams (top width at floodstage < 100 ft) 1. Main Channels a. clean, straight, full stage, no rifts or deep pools 0.025 0.030 0.033 b. same as above, but more stones and weeds 0.030 0 035 I 0.040 I c. clean, winding, some pools and shoals 0.033 0.040 0.045 - d. same as above, but some weeds and stones 0.035 0.045 0.050 i e. same as above, lower stages, more ineffective 0.040 0.048 0.055 slopes and sections f. same as "d"with more stones 0.045 0.050 0.0601 g. sluggish reaches. weedy, deep pools 0.050 0.070 0.080 h. very weedy reaches, deep pools, or floodways 0.075 0.100 0 150 with heavy stand of timber and underbrush I 2. Mountain streams, no vegetation in channel, banks usually steep, trees and brush along, banks submerged at high stages a. bottom: gravels, cobbles, and few boulders 0.030 0.040 0 050 1 b bottom: cobbles with large boulders 0.040 0.050 0.070 3. FloodplainsI a. Pasture, no brush 1.short grass 1 0.025 0.030 0.035 ir» 2. high grass 0.030 0.035 ' 0.050 II b. Cultivated areas 1. no crop 0.020 0.030 0.040 2. mature row crops 0.025 0.035 0.045 3. mature field crops 0.030 0.040 0.050 c. Brush 1. scattered brush, heavy weeds 0.035 0.050 0.070 2. light brush and trees, in winter 0.035 0.050 0.060 3. light brush and trees, in summer 0.040 0.060 0.080- 4. medium to dense brush, in winter 0.045 0 070 0.110 5 medium to dense brush, in summer 0.070 0-100 0.1601 d. Trees 1. dense willows, summer, straight 0.110 0.150 0.200 a http://www.fsl.orst.edu/geowater/FX3/help/8_Hydraulic_Reference/Mannings__n_Tables.... 11/10/2016 a Channel Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk,Inc. Friday,Mar 3 2017 Channel A18 Flexamat Lined Triangular Highlighted Side Slopes (z:1) = 3.00, 3.00 Depth (ft) = 0.79 Total Depth (ft) = 1.00 Q (cfs) = 9.000 Area (sqft) = 1.87 Invert Elev (ft) = 1.00 Velocity (ft/s) = 4.81 Slope (%) = 5.00 Wetted Perim (ft) = 5.00 N-Value = 0.035 Crit Depth, Yc (ft) = 0.90 Top Width (ft) = 4.74 Calculations EGL (ft) = 1.15 Compute by: Known Q Known Q (cfs) = 9.00 1 Elev (ft) Depth ft( ) Section 3.00 — ----- — 2.00 2.50 1.50 I 2.00 -- — 1.00 1.50 - 0.50 I 1 I 1.00 - 0.00 0.50 — -0.50 0 1 2 3 4 5 6 7 8 Reach (ft) I SCS ENGINEERS I Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Startion 02216108.01 Subject By Date Channel A19 NTJ/DCC 7/14/2017 Checked Date Sheet 1 of 1 AST 7/14/2017 Purpose: Channel geometry,and lining adequacy for channel A19. Given: 1.Channel Geometry,V-ditch 1.5 foot depth,3:1 side slopes: 2.Flow from Area A peak flow calculations, Qp= 9 cfs 3.Average slope of channel,S= 8 Assumptions: I 1.mannings number= 0.035 2.Channel Lining Velocity Ranges Velocity Lining 0-3 ft/sec Grass 0-4 ft/sec EC-2 VDOT matting 4-10 ft/sec EC-3 VDOT matting I 10+ft/sec Flexamat® Calculations: See attached Hydraflow express calculations: Velocity= 5.79 ft/sec Conclusions: The channel can adequatly handle the peak flow of 9.0 cfs,and Flexamat®should be used as the lining. I I I 1 I I I I I Precipitation Frequency Data Server Page I of 4 NOAA Atlas 14,Volume 2,Version 3 Location name:Charlottesville,Virginia,USA* 6 Latitude:38.0253°,Longitude:-78.6838° 11111', y ' Elevation:662.27 ft** �s / `source:ESRI Maps t..,„F "source:USGS POINT PRECIPITATION FREQUENCY ESTIMATES i G_M.Bonnin,D.Martin,B Lin,T.Parzybok,M Yekta,and D.Riley NOAA,National Weather Service,Silver Spring,Maryland PF tabular)PF straDhica1 I Maps & aerials PF tabular PDS-based point precipitation frequency estimates with 90% confidence intervals(in incheslhour)1 Duration i Average recurrence interval(years) f 1 2 5 I 10 M� 25 50 100 200 500 II 1000 5-min 4.12 4.92 5.80 `� 6.63 7.37 8.02 9.20 (( 9.90 10.5 (3.72-4.57) (4.45-5.45) (5.23-6.41)q(5.88-7.21) (6.60-8.11) (7.15-8.83) (8.09.10.2)�t (8.60-11 0) (9.00-11.7)-1 10-min 3.29 3.94 4.64 '5.'12 ` I 6.87 - 6.38 6.86 7.30 7.83 �1' 8.24 (2.98.3.65) (3.58-4.36) (4.19-5.13) (4.70-5.76) (5.26-6.47) (5.69.7.03) (6.08-7.56) (6.41-8.06) (6.80-8.69) (7.09-9.19) 15-min 2.74 3.30 3.92 4.40 4.96 5.39 5.78 6.14 6.57 6.90 (2.48-3.04) (2.99.3.55) (3.54-4.32) I(3.97.4,86) (4.45.5.46) (4.80.5.94) (5.12.6.37) (5.40-6.78) . (5.71-7.29) (5.93-7.69) 30-min 1.88 2.28 2.78 3.19 3.67 4.06 4.42 4.78 5.23 6.69 (1.70.2.08) (2.06.2.52) (2.51-3.07) (2.87.3.52) (3.29-4.05) (3.62-4.47) (3.92-4.88) (4.20.528) (4.54-5.80) (4.80-6.23) int 60-min 1.17 1.43 1.78 2.08 2.45 2.75 3.06 3.36 3.75 4.08 (1.06-1.30) (1,29-1.58) (1.61-1.97) (1.87-2.29) (2.19-2.70) (2.45-3.03) (2.70-3.36) (2.95-3.70) (3.26-4.18) (3.51.4.55) 2-hr 0.700 0.852 1.07 1.26 , 1.50 1.70 1.91 2.12 2.42 2.87 (0.622-0.792)(0.756.0.961) (0.948-1.20) (1.12-1.41) I (1.32.1.88) (1.49-1.91) (1.86-2.14) (1.83-2.38) (2.06-2.73) (2.25-3.02) 3-hr 0.611 0.621 0.778 0.914 I 1.09 1.24 1.39 1.55 1.77 1.96 IN (0.454-0.582)(0.549-0.705)(0.687-0.884) (0.805-1.04) (0.956.1.23) (1.08-1.40) (1.21-1,58) (1.33-1.76) (1.50-2.02) (1.64-2.24) 6-hr 0.331 0.401 0.498 0.587 0.705 0.809 0.918 1.04 1.20 1.35 (0.296-0.374)(0.357-0.452) (0.442-0.561)(0.518-0.660)(0.619-0.793)(0.704-0.908)_(0.791-1.03) (0-882-1.17) (1.01-1.36) (1.12-1.53) 12-hr 0.209 0.252 0.315 0.372 0.453 0.525 0.603 0.689 0.817 0.932 (0.186.0.238)(0.224.0.288)(0.278.0.358)(0.328-0.423)(0.396.0.514)(0.453.0.595)(0.514-0.684)(0.579.0.782)(0.671.0.931) (9.753.1.07) AO I 24-hr 0.127 0.154 0.196 0.231 0.284 0.329 0.378 0.433 0.514 0.683 (0.114-0.142);0.138-0.172) (0.176-0.219)(0.207-0.258)(0.252.0.316){0.289.0.365)(0.330.0.420)(0.374.0.479)(0.436.0.570)(0.488-0.847) 2-day 0.075 0.0911. 0.115 0.135 0,154 0.188 0.215 0.243 0.285 0.320 (0.067-0.083) 0.081-0101)(0.103-0.128)(0.121-0.151) (0.146-0.183)(0.166.0.209),(0.188.0.239)(0.211-0.271)(0.244-0.318)(0271-0.358) 3-day 0:053 0.064 0.082 0.096 0.116 0.133 0.162 0.172 0.201 0.226 (0.048-0.059)1(0,058.0.071)(0.074.0.090)(0.086-0.106)(0.104-0.128)(0.119-0.147),(0.134.0.168)(0.151-0.190)(0.174-0.223)(0.193-0.251) - 4-day 0.042 0.061 0.065 0.076 0.092 0.106 0.120 0.136 0.159 0.178 (0.039.0047)(0.047-0.056)(0.059.0.072)(0,069.0.084)(0.083-0.101)-{0.095.0.116)(0.107-0.132)(0.120-0.150)(0.139-0.175)(0.154-0.197) I 7-day 0.028 0.034 0.042 0,049 0.059 0.067 0.076 0.0860.098 0.109 (0.026-0.031)(0.031.0.037)(0.039-0.046)(0.045.0.053)(0.053-0.064) (0.060-0.073)(0.068-0.083)(0.0750.093)(0.086-0.108 (0.095-0.120) 10-day 0.022 0.027 0.033 0.038 0.045 0.051 0.057 0.063 0.072 0.079 (0.020-0.024) (0.025-0.029)(0.030-0.036)(0.035-0.041)(0.041.0.049)(0.046-0.055)(0.051-0.061)(0.057-0.068)(0.064.0.078 (0.070.0.086) 20-day 0.015 0.017 0.021 0.024 0.028 0.031 0.034 0.037 0.041 0.044 (0.014-0.016)(0.016-0.019)(0.020-0.023)(0.022.0.026)(0.026.0.030)(0.028.0.033)(0.031-0.036)(0.034-0.040)(0.037.0.044)(0040-0.048) 30-day 0.012 0.014 0.017 0-019 0.021 0.023 0.025 0.027 0.029 0.031 (0.011.0.013) 0.013-0.015 (0.016.0.018)(0.017-0.020)(0.020.0.023)(0.022-0.025)N(0.023-0.027)(0.025-0.029)(0.027-0.031)(0.029.0.033) 45-day 0.010 0.012 0.014 0.015 0.017 0.(r .02018 0 0.021 0.023 0.024 (0.009.0.011)(0.011.0.012)(0.013-0,015) 0.014-0.018)(0.016.0.018)(0.017.0.020)(0.018-0.021)(0.020-0.022)(0.021-0.024)(0.022.0.026) I 60-day 0.009 0.010 0.012 0.013 1-0.014 0.016 II 0.017 0.018 0.019 0.020 (0.008.0.009)(0.010-0.011)(0.011-0.013)0.012-0.014)(0.014-0.015)(0.015-0.016)'(0.016.0.018){0.016-0,019)(0.018.0.020)(0.018-0.021) 'Precipitation frequency(PF)estimates in this table are based on frequency analysis of partial duration series(PDS) Numbers in parenthesis are PF estimates at lower and upper bounds of the 90%confidence interval,The probability that precipitation frequency estimates (for a given duration and average recurrence interval)will be greater than the upper bound(or less than the lower bound)is 5%.Estimates at upper bounds are not checked against probable maximum precipitation(PMP)estimates and may be higher than currently valid PMP values. Please refer to NOAA Atlas 14 document for more information. Back to Top I i in, I http://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?tat=38.0253&lon=-78.6538&dat... 11/21/2016 I 6.4— Design Concepts -- I The Rational Method Formula is expressed as follows: Q = CfCiA (6.4) Where: Q = Maximum rate of runoff, cubic feet per second (cfs) Cf = Saturation factor C = Runoff coefficient representing a ratio of runoff to rainfall (dimensionless) i = Average rainfall intensity for a duration equal to the time of concentration for a selected return period, inches per hour (in/hr) A = Drainage area contributing to the point of study, acres (ac) Note that conversion to consistent units is not required as 1 acre-inch per hour approximately equals 1 cubic foot/second, 6.4.4.1.5 Infrequent Storm The coefficients given in Appendix 6E-1 are for storms with less than a 10-year recurrence interval. Less frequent, higher intensity storms will require modification of the coefficient because infiltration and other losses have a proportionally smaller effect 111 on runoff (Wright-McLaughlin 1969). The adjustment of the Rational Method for use with larger storms can be made by multiplying the right side of the Rational Formula by a saturation factor, Cf The product of Cf and C should not 1.0. Table 6-2 lists the saturation factors for the Rational Method, Table 6-2. Saturation Factors For Rational Formula 1 Recurrence Interval (Years) Cf 2, 5, and 10 1.0 25 1.1 50 1.2 100 1.25 Note: Cf multiplied by C should not 1.0 6,4.4.1.6 Time of Concentration The time of concentration is the time required for water to flow from the hydraulically most remote point in the drainage area to the point of study. Use of the rational formula requires the time of concentration (tc) for each design point within the drainage basin. The duration of rainfall is then set equal to the time of concentration and is used to estimate the design average rainfall 1 intensity A table bhowing the B, D, & E factors fory using the B, D, & E factors in procedure described in Appendix Virginia counties and larger cities is presented in Appendix 6C-2. * Rev 4/10 . _ VDOT Drainage Manual 6—Hydrology 6-16 of 57 1992 TABLE 5-2 VALUES OF RUNOFF COEFFICIENT (C) FOR RATIONAL FORMULA Land Use C Land User_____-_C Business: Lawns: Downtown areas 0.70-0.95 Sandy soil, flat, 2% 0.05-0.10 - Neighborhood areas 0.50-0.70 Sandy soil, average, 2-7% 0.10-0.15 Sandy soil, steep, 7% 0.15-0.20 Heavy soil, flat, 2% 0.13-0.17 Heavy soil, average, 2-7% 0.18-0.22 Heavy soil, steep, 7% 0.25-0.35 QSt 03' Residential: Agricultural land: Single-family areas 0.30-0.50 Bare packed soil Multi units, detached 0.40-0.60 * Smooth 0.30-0.60 Multi units, attached 0.60-0.75 * Rough 0.20-0.50 Suburban 0.25-0.40 Cultivated rows * Heavy soil, no crop 0.30-0.60 * Heavy soil, with crop 0.20-0.50 * Sandy soil, no crop 0.20-0.40 * Sandy soil, with crop 0.10-0.25 Pasture * Heavy soil 0.15-0.45 * Sandy soil 0.05-0.25 Woodlands 0.05-0.25 Industrial: Streets: Light areas 0.50-0.80 Asphaltic 0.70.0.95 ` ` Heavy areas 0.60-0.90 Concrete 0.80-0.95 (Z)' 1° Brick 0.70-0.85 Parks, cemeteries 0.10-0.25 Unimproved areas 0.10-0.30 Playgrounds 0.20-0.35 Drives and walks 0.75-0.85 Railroad yard areas 020-0.40 Roofs 0.75-0.95 LNote: The designer must use judgement to select the appropriate "C" value within the range. Generally, larger areas with permeable soils, flat slopes and dense vegetation should have the lowest C values. Smaller areas with dense soils, moderate to steep slopes, and sparse vegetation should be assigned the highest C values. ■ - Source: Arriericart_Society of Civil Engineers I I V - 29 Manning's n Values Page 1 of 5 1 Show Manning's n Values ♦" inN► 111 Reference tables for Manning's n values for Channels, Closed Conduits Flowing Partially Full, and Corrugated Metal Pipes. VSE 4.*03C -.7 ,4(cov -_ as - -,- " Cz�LAcs .w 1 t� R/4 t� Manning's n for Channels (Chow, 1959). I Type of Channel and Description Minimum Normal Maximum Natural streams - minor streams (top width at floodstage< 100 ft) I. 1. Main Channels a. clean, straight, full stage, no rifts or deep pools 0.025 0.030 0.033 i1 b. same as above, but more stones and weeds 0.030 0.035 0.040 c. clean, winding, some pools and shoals 0.033 0.040 0.045 d. same as above, but some weeds and stones 0.035 0.045 0.050 e. same as above, lower stages, more ineffective 0.040 0.048 0.055 slopes and sections f. same as"d"with more stones 0.045 0.050 0.060 g. sluggish reaches, weedy. deep'pools 0.050 0.070 0.080 • h. very weedy reaches, deep pools, or floodways 0.075 0.100 0.150 with heavy stand of timber and underbrush 2. Mountain streams, no vegetation in channel, banks usually steep,trees and brush along banks submerged at high stages a. bottom: gravels, cobbles, and few boulders 0 030 0.040 0.050 1 b. bottom: cobbles with large boulders 0.040 0.050 0.070 3. Floodplains a. Pasture, no brush 1.short grass 0.025 0.030 0.035 2. high grass 0.030 0.035 0.050 b. Cultivated areas 1. no crop 0.020 0.030 0.040 2. mature row crops 0.025 0.035 0.045 3. mature field crops 0.030 0.040 0.050 c. Brush 1. scattered brush, heavy weeds 0.035 0.050 0.070 2. light brush and trees, in winter 0.035 0 050 0.060 3. light brush and trees, in summer 1 0.040 0.060 0.080 1 4. medium to dense brush, in winter 0.045 0.070 0.110 5. medium to dense brush, in summer 0.070 0.100 0.1601 d. Trees 1. dense willows, summer, straight 0.110 0.150 0.200 a http://www.fsl.orst.edu/geowater/FX3/help/8_Hydraulic_Reference/Manni ngs__n_Tables.... 11/1 0/2016 a Channel Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D6 by Autodesk,Inc. Friday,Mar 3 2017 Channel A19 Flexamat Lined . Triangular Highlighted Side Slopes (z:1) = 3.00, 3.00 Depth (ft) = 0.72 Total Depth (ft) = 1.50 Q (cfs) = 9.000 Area (sqft) = 1.56 Invert Elev (ft) = 1.00 Velocity (ft/s) = 5.79 Slope (%) = 8.00 Wetted Perim (ft) = 4.55 N-Value = 0.035 Crit Depth, Yc (ft) = 0.90 Top Width (ft) = 4.32 _ Calculations EGL (ft) = 1.24 Compute by: Known Q Known Q (cfs) = 9.00 — Elev ( ) Depth ft (ft) Section 3.00 -- 2.00 II I ::: / 1.00 v II 1.50 --- 0.50 I 1.00 I — 0.00 i 1 0.50 -0.50 0 1 2 3 4 5 6 7 8 9 10 11 Reach (ft) I I Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108.01 Subject By Date I Channel A20 NTJ/DCC 7/14/2017 Checked Date Sheet 1 of 1 AST 7/14/2017 Purpose: Determine the adequacy of Channel A20 for a 10 year storm event.And required liner type. 1 Given: I Contributing Drainage Area,A: 7844.419 sq.ft. 0.18 acre Channel Size 3:1 Sides slopes Depth,D: 9 inches Slope of Channel 8.1 Assumptions: Rainfall Intensity(Atlas 14),i: 6.53 in/hr use 5 min duration Roughtness Coefficent,C: 0.90 mannings roughness: 0.035 Velocity Lining 0-3 ft/sec Grass 0-4 ft/sec EC-2 VDOT matting 4-10 ft/sec EC-3 VDOT matting I 10+ft/sec Flexamat® Calculations: Peak Flow Qp=C*i*A 1.06 cfs Depth of Water in Channel 0.33 ft from express calculationsI Velocity 3.24 fps from express calculations Conclusions: Channel A20 is adequately size to handle the 10 year storm event. Use EC-2 VDOT Matting for 3.24 fps. I I I I I 10 III ill MK MI I. a Precipitation Frequency Data Server Page 1 of 4 OM NOAA Atlas 14,Volume 2,Version 3 Location name:Charlottesville.Virginia,USA* '- ✓ Latitude:38.0253°,Longitude:-78.6538° • . Elevation:662.27 ft" ' a a,'vvo 'source:ESRI Maps -'source:USGS POINT PRECIPITATION FREQUENCY ESTIMATES G M.Bonnin,D Martin,B Lin,T Parzybok,M Yekta,and D Riley a NOAA,National Weather Service,Silver Spring,Maryland PF tabular I PF graphical I Maps & aerials a PF tabular PDS-based point precipitation frequency estimates with 90%confidence intervals(in inchesthour)1 Average recurrence interval(years) i Durationii 1 1 -1 2 5 10 25 I 50 100 200 500 1-7.1011-0-1 5-min II 4.12 1 4.92 5.80 6.63 7.37 8.02--I- 8.63 9.20 9.90 10.6 I (3.72-4.57) I(4.45-5.45) I(5.23-6.41)II (6:87.21) (6.60-8.11) (7.15-8.83) (7.64-9.52) (8.09-10.2) (8.60 11.0) 19.00-11 7) 10-min 3.29 3.94 4.64 5.22 5.87 ( 6.38 6.86 7.30 7.83 -I 8.24 (2.98-3 65) (3.56-4.36) (4.19-5.13) (4.70-5.76) (5.26-6.47) I (5.69-7.03) (6.08-7.56) (6.41-8.06) (6,80-8.69) (7.09-9.19) mow15-mini 2.74 3.30 3.92 4.40 4.96 5.39 5.78 6.14 6.57 6.90 _(2.48-3.04) 12.99-3,65) (3.54-4.32) (3,97-4.86) (4.45-5.46) ((4,80-5.9_4) (5,12-6,37) (5.40.6.78)_ (5.71-7.29) (5.93-7.69) 30-min 1.88 2.28 2.78 3.19 3.67 4.06 4.42 4.78 6.23 5.59 (1.70-2,08) (2.06-2.52) (2.51-3.07) (2.87-3.52)- (3.29.4.05) 1_(3.62-4.47) (3.92-4.88) (4.20.5.28) (4.54-5.80) (4.80.6.23). 60-min 1.17 1.43 1.78 2.08 2.45 2.75 3.06 3.36 �3.7b 4.08 a (106-130) (1.29-1.58) (1,61-1.97) (1.87-2.29) (2.19-2.70) (2,45-3.03) (2.703.36) (2.95-3.70) (3.26-4.16) (3.51-4.55)- 2-hr 0.700 0.852 1.07 1.26 1.50 1.70 1.91 2.12 2.42 2.67 (0.6.22-0.792)(0.756-0.961) (0.948-1.20) (1.12-1.41) (1.32.1.68) (1.49.1.91) (1,66-2.14) (1.83-2.38) (2.06-2.73) ((2.25-3.02) 3-hr 0.511 0.621 0.778 0.914 1.09 1.24 1.39 1.55 1.77 1.96 (0.454-0.582) (0.549-0.705)(0.687-0.884) (0.805-1.04) (0.956-1.23) (1.08-1.40) (1.21-1.58) (1.33-1.76) (1.50.2.02) (1.64.2.24)1 r 1-6-hr 0.331 0.401 0.498 0.587 0.705 0.809 0.918 1.04 1.20 1.36 (0.296-0.374) (0.357-0.45211(0.442.0.561)1(0.518.0.660)1I(0.619-0.793)(0.704-0.908)`(0.791-1.03),l(0.882-1.17)1(1.01-1.36) (1.12.1.53) , 12-hr 0.209 0.252 0.316 0.372 0.453 0.525 0.603 0.689 0.817 0.932 _(0.186-0.238)10.224-0.288)(0.278.0.358)(0.328-0.423)(0.396.0.514)(0.453-0.595)(0.514-0,684)(0.579-0.782)(0.671-0.931) (0.753-1 07)1 24-hr 0.127 [ 0.154 0.196 ([ 0.231 II 0.284 11 0.329 �r 0.378 1`J 0.433 0.514 if 0.583 l - (0.114-0.142)((0.138-0.172)(0.176-0.219)p).207.0.258) (0.252-0.316)((0.289.0.365)((0.330-0.420)`(0.374-0.479)(0.436-0.570)IE(0.488-0.6471) 2-day 0.076 0.091 0.115 0.135 0.164 0.188 0.215 0.243 0.285 0.320 (0.067-0.083) 0.081-0.101)(0.103.0.128)(0.121-0.151)(0.146-0.183)ll(0.166-0.209).(0.188-0.239)(0.211-0.271)(0.244.0.318)(0.271-0.358) 3-day 0:053 0.064 0.082 0.096 11 0.116 0.133 ' 0.152 0.172 0.201 0.225 (0.048-0.059)(0.058-0.071) (0.074-0.090)(0.086.0.1061(0.104-0.128) (0.119-0.147)(0.134-0.168)(0.151-0.190)(0.174.0.223)(0.193-0.251) 4-day4. 0.042 0.051 0.065 0.076 0.092 0.106 0.120 0.136 0.159 0.178 (0.039.0.047) (0.047.0.056)10.059-0.072) 0.069-(1.084) (0.083.0.101)(0.095-0.116)(0.107.0.132)(0.120-0 150)(0.139-0.175))[(0.154-0.1971 7-day 0.028 0.034 0.042 0.049 r 0.059 0.067 0.076 0.085 0.098 0.109 (0.026-0.031) (0.031-0.037)(0.039-0.046)10.045-0.053)(0.053.0.064)10.060-0.073)((0,068-0.083)(0.075.0.093)(0.086-0.108)(0.095-0.120) +� 10-day 0.022 0.027 0.033 0.038 0.045 0.051 0.057 0.063 0.072 0.079 (0.020-0.024)x(0.025-0.029)(0.030.0.036)(0.035-0.041)(0.041-0,049)(0.046-0.0.55)(0.051-0.061)(0.057-0.0681(0.064-0.078)10.070-0.086) 20-day 0.015 0.017 0.021 0.024 0.028 0.031 0.034 0.037 0.041 0.044 (0,014-0.016)(0.016-0019)(0.020.0.023)(0.022-0.026)(0.026.0.030)(0.028-0.033),(0.031.0.036}(0.034.0.040)(0.037.0.044)I(0.040.0.046) 30-day 0.012 0.014 0.017 0.019 0.021 0.023 0.025 0.027 0.029 0.031 [4AO 5-day (0.011.0.0121(0.013-0.015(0.016-OA18)I 40.017.0.020)(0.020-0.023)(0.022.0.025)9(0.023-0.027)(0.025.0.029)(0.027-0.031) 0.029.0.033) 45-day 0.010 )ll P0.012^ 0.014 I(- 0.015 0.017 1 0.018 0.020 I(- 0.021 I1 0.023 11(�0.024 (0.009.0.011 Ik0.011-0.012)(0.013-0.015) (0.014-0,016)(0.016.0.018)`(0.017-0,020).,(0.018.0.021)I(0.020-0.022)`(0.021.0.024 0.022-0.026) 0.009 0.010 0.012 0.013 0.014 0.016 I 0.017 0.018 0.019 0.020 1 60-day (0.008-0.009)(0.010-0.011)11(0.011-0`013))I(1).012-0.014)(0.014-0,015) (0.015.0.016)'(0.016-0.018)(0.016-0.019)(0.018.0.020)1(0.018-0.021) ' 'Precipitation frequency(PF)estimates in this table are based on frequency analysis of partial duration series(PDS). Numbers in parenthesis are PF estimates at lower and upper bounds of the 90%confidence interval.The probability that precipitation frequency estimates (for a given duration and average recurrence interval)will be greater than the upper bound(or less than the lower bound)is 5%.Estimates at upper bounds are not checked against probable maximum precipitation(PMP)estimates and may be higher than currently valid PMP values. - Please refer to NOAA Atlas 14 document for more information. Back to Top I I I I http://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.htm l'?tat=38.0253&1on=-78.6538&dat... 11/21/2016 I 1992 1 TABLE 5-2 I VALUES OF RUNOFF COEFFICIENT (C) FOR RATIONAL FORMULA 1 Land Use C Land Use C I Business: Lawns: Downtown areas 0.70-0.95 Sandy soil, flat, 2% 0.05-0.10 Neighborhood areas 0.50-0.70 Sandy soil, average, 2-7% 0.10-0.15 Sandy soil, steep, 7% 0.15-0.20 Heavy soil, flat, 2% 0.13-0.17 Heavy soil, average, 2-7% 0.18-0.22 Heavy soil, steep, 7% 0.25-0 35 OSE. c)-,," Residential: Agricultural land: Single-family areas 0.30-0.50 Bare packed soil Multi units, detached 0.40-0.60 * Smooth 0.30-0.60 l Multi units, attached 0.60-0.75 * Rough 0.20-0.50 � Suburban 0.25-0.40 Cultivated rows I * Heavy soil, no crop 0.30-0.60 * Heavy soil, with crop 0.20-0.50 * Sandy soil, no crop 0.20-0.40 I * Sandy soil, with crop 0.10-0.25 Pasture * Heavy soil 0.15-0.45 * Sandy soil 0.05-0.25 I Woodlands 0.05-0.25 Industrial: Streets: Light areas 0.50-0.80 Asphalt{€` .- 0.70-0.95 'Y"' I Heavy areas 0.60-0.90 Concrete 0.80-0.95 O'"° Brick 0.70-0.85 Parks, cemeteries 0.10-0.25 Unimproved areas 0.10-0.30 1 Playgrounds 0.20-0.35 Drives and walks 0.75-0.85 Railroad yard areas 0.20-0.40 Roofs 0.75-0.95 1 Note: The designer must use judgement to select the appropriate "C" value within the range. Generally, larger areas with permeable soils, flat slopes and dense vegetation should have the lowest C values. Smaller areas with dense soils, moderate to steep slopes, and sparse vegetation should be assigned the highest C values. a Source: American Society of Civil Engineers ma am V - 29 a Channel Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk,Inc. Friday,Mar 3 2017 Channel A21/ A18 VDOT STD Paved Ditch Type A Triangular Highlighted Side Slopes (z:1) = 6.00, 4.00 Depth (ft) = 0.21 Total Depth (ft) = 0.50 Q (cfs) = 2.000 Area (sqft) = 0.22 Invert Elev (ft) = 1.00 Velocity (ft/s) = 9.07 Slope (%) = 13.30 Wetted Perim (ft) = 2.14 N-Value = 0.013 Crit Depth, Yc (ft) = 0.40 Top Width (ft) = 2.10 Calculations EGL (ft) = 1.49 Compute by: Known Q Known Q (cfs) = 2.00 Elev ft ( ) Depth (ft) Section 2.00 - 1.00 - 1.75 0.75 1.50 - 0.50 1.25 4NNN.%'%N. 0.25 1.00 0.00 0.75 -0.25 0 1 2 3 4 5 6 7 Reach (ft) r. 1 1 Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108.01 Subject By Date A18/A21 Paved VDOT Channel NTJ/DCC 7/14/2017 Checked Date Sheet 1 of 1 AST 7/14/2017 Purpose: Determine Peak Flow for a 10 yr storm for Channel A21 Given: Total Drainage Area,A: 5767.579 sq.ft. 0.13 acre Assumptions: Assume 5 minute duration therefore,Rainfall Intensity,i= 6.53 in/hr Runoff Coefficent,C: 0.90 assume entire area paved. Channel Dimensions per VDOT Standard Paved Ditch PG-2A,Type Al Calculations: Peak Flow Qp=C*i*A 0.78 cfs use 2 cfs for design. Conclusions: Channel A21 lined with VDOT type Al is adequate to handle the design peak flow. Also,use PG-2A type Al paved ditch for channel A18(smaller drainage area). I I 1 ✓ S s S s L Precipitation Frequency Data Server Page 1 of 4 km NOAA Atlas 14,Volume 2,Version 3 Location name:Charlottesville,Virginia,USA" ./'V.--."'.` MN 0 Latitude:38.0253°,Longitude:-78.6538° Elevation:662.27 ft** 'source'E5RI Maps "source'USGS POINT PRECIPITATION FREQUENCY ESTIMATES G M Bonnin,,D Martin,8 Lin,T Farzybok,M Yekta,and D Riley klo NOAH,National Weather Service,Silver Spring,Maryland PF tabular(PF graphical I Maps & aerials PF tabular PDS-based point precipitation frequency estimates with 90%confidence intervals(in inches/hour)1 Duration I Average recurrence interval(years) 1 1 2 5 OMMI 25 50 100 200 11 500 I 1000 AM 5-m)n 4.12 4.92 6.80 6.53 7.37^ 8.02 8.63 9.20 9.90 10.5 (3.72-4.57) (4.45-5.45) (5,23-6.41) (5.88-7.21) (6.60-8.11) (7.15-8.83) (7.64-9.52) (8.09-10.2) (8.60-11.0) (9.00-11.7)1 10-min 3.29 3.94 4.64 :.22'"- 6.87 6.38 6.86 7.30 7.83 8.24 (2.98-3.65) (3.56-4.36) (4.19-5.13) (4.70-5.76) (5.26-6A7) (5.69-7.03) , (6.08-7.56) (6.41-8.06) (6.80.8.69) (7.09-9.19) 2.74 3.30 3.92 4.40 4.96 6.39 5.78 6.14 6.67 6.90 am 15-min r(2.48-3.04) (2,99-3.65) (3.54-4.32) (3.97-4.86) 1(4.45-5.46) (4.80-5.94)1 (5.12-6.37) (5.40-6.78) (5.71-7.29) (5.93.7,69)) 30-min 1.88 2.28 2.78 3.19 3.67 4.06 4.42 4.78 5.23 6.69 (1.70.2.08) (2.06.2.52) (2.51-3.07) (2.87-3.52) (3.29-4.05) (3.62-4.47) (3.92-4.88) (4.20-5.28) (4.54-5.80) (4.80-6.23) 60-min 1.17 1.43 1.78 2.08 2.45 2.75 3.06 3.35 [ 3.76 4.08 (1.06-1.30) (1.29.1.58) (1.61.1.97) (L87-2.29) (2.19-2.70) (2.45-3.03) (2.70-3.36) (2.95-3.70) I (3.26-4.16) (3.51-4.55) ma 2-hr 0.700 0.862 1.07 1.26 1.50 1.70 1.91 2.12 2.42 2.67 (0.622-0.792)(0.756.0.961) (0.948-1.20) (1.12-1.41) (1.32-1.68) (1.49-1.91) (1.66-2.14) (1.83-2.38) (2.06-2.73) (2.25-3.02) 3-hr 0.611 0.621 0.778 0.914 1.09 1.24 1.39 1.55 1.77 1.96 (0.454-0.582)(0.549.0.705)(0.687-0.884) (0.805.1.04) (0.956-1.23) (1.08-1.40) (1.21-1.58) (1.33-1.76) (1.50-2.02) (1.64-2.24) rim6-hr 0.331 0.401 0.498 0.587 0.706 0.809 0.918 1.04 1.20 1.36 (0.296.0.374)(0.357.0.452)(0.442-0.561)(0.518-0.660)(0.619-0,793)(0.704-0.908) (0.791.1.03) (0.882-1.17) (1.01-1.36) (1.12-1.53) 12-hr 0.209 0.262 0.316 0.372 0.453 0.525 0.603 0.689 0.817 0.932 (0.186.0.238)(0.224.0.288)(0.278-0.358)(0.328-0.423)(0.396-0.514)(0.453-0.595)(0.514-0.684)(0579-0.782)(0.671-0.931) (0.753-1.07) 24-hr 0.127 0.164 0.196 0.231 0.284 0.329 0.378 -11 0.433 0.514 0.583 WIN (0,114.0.142)(0.138-0.172)(0.176-0.219)(0.207-0.258)(0.252-0.316)(0.289-0.365)(0.330-0.420)(0 374-0 479)(0.436.0.570)(0.488-0.647) I 2-day1 0.075 0.091 0.116 0.135 1 0.164 0.188 0.216 0.243 0.285 0.320 L.. (0,067.0.083)(0.081.0.101)(0.103-0.128) 0.121-0151)(0.146-0,183)(0.166-0.209)(0.188-0.239)I(0.211.0.271)(0.244-0.318)11(0.271-0.358)! ( 3-day 0.063 0.064 0.082 0.096 0,116 0.133 0.162 0.172 0.201 0.226 ._](0.048-0.059)(0.058-0.071)(0.074.0.090)(0.086.0.106)l(0.104-0.128)(0.119.0.147)'(D.134.0.168)(0.151-0.190)(0.174-0.223)(0.193-0251)) i 4-day 0.042 0.061 0.066 0.076 0.092 0.106 0.120 0.136 ` 0.169 0.178 L (0.039.0.047)(0.047-0.056)(0.059.0.072)(0.069.0.0841(0.083.0.101) 0.095.0.116)(0.107.0.132)(0.120-0.150)(0.139.0.175 (0.154-0.197) I-7 7-da 0.028 0.034 0.042 0.049 0.069 0.067 0.076 0.086 0.098 0.109 -day]1(0.026.0.033 (0.031-0.037)(0.039-0.046)(0.045-0,053)10.053.0.064)(0.060.0.073)(0.068.0.083)(0.075-0.093)(0.086.0.108)(0 099-0.120) um 10-day 0.022 0.027 0.033 0.038 0.046 0.061 0.067 0.063 0.072 0.079 (0.020-0.024)(0.025.0.029)(0.030.0.036)(0.035.0.041)1(0.041.0-049 (0.046.0.055),(0.051.0,061)(0.057-0.068((0.064.0.078)(0.070.0.086) 20-day 0.016 0.017 0.021 0.024 0.028 0.031 0.034 0.037 0.041 0.044 (0.014-0.016)(0.016.0.019)(0.020-0.023)(0.022-0.026) 10,026-0.030)(0.028-0.033)(0.031.0.036)(0.034-0.040)(0.037-0.044)(0.040-0.048)1 30-day 0.012 0.014 0.017 0.019 0.021 0.023 0.025 0.027 0.029 0.031 (0.011.0.013)(0.013-0.015)(0.016-0.018)(0.017.0.020)(0.020-0.023)(0.022-0.025),(0.023-0.027)(0.025-0.029)(0.027-0.031)(0.029-0,033) ma 0.010 0.012 0.014 0.015 0.017 0.018 - 0.020 0.021 0.023 0.024 45-day (0.009.0.011)(0.011-0.012)(0.013-0.015)(0.014-0.016)'(0.016.0.018)(0.017-0.020),(0.018-0.021)(0.020-0.022)(0.021-0.024)(0.022-0.026) (0.0 60-day 0.009 0.010 0.012 1 0.013 0.014 0.016 0.017 0.016 0.019 0.020 (0.008.0.009)(0.010-0.011)(0.011-0.013) 12-0.014)'(0.014-0.015)(0.015-0.016)(0.016-0.018)(0.016-0.019)(0.018-0.020)(0.018-0.021)l INI 1 Precipitation frequency(PF)estimates in this table are based on frequency analysis of partial duration series(PDS). Numbers in parenthesis are PF estimates at lower and upper bounds of the 90%confidence interval The probability that precipitation frequency estimates (for a given duration and average recurrence interval)will be greater than the upper bound(or less than the lower bound)is 5%.Estimates at upper bounds are not checked against probable maximum precipitation(PMP)estimates and may be higher than currently valid PMP values. Please refer to NOAA Atlas 14 document for more information am Back to Top 4r http://hdsc.nws-noaa.gov/hdsc/pfds/pfds_printpage.htm l?Iat=38.0253&Ion=-78.653 8&dat... 11/21/2016 I 1992 1 TABLE 5-2 I VALUES OF RUNOFF COEFFICIENT (C) FOR RATIONAL FORMULA I Land Use C Land Use C I Business: Lawns: Downtown areas 0.70-0.95 Sandy soil, flat, 2% 0.05-0.10 I Neighborhood areas 0.50-0.70 Sandy soil, average, 2-7% 0.10-0.15 Sandy soil, steep, 7% 0.15-0.20 Heavy soil, flat, 2% 0.13-0.17 Heavy soil, average, 2-7% 0.18-0.22 t Heavy soil, steep, 7% 0.25-0.35 .)St 0.3' Residential: Agricultural land: Single-family areas 0.30-0.50 Bare packed soil I Multi units, detached 0.40-0.60 * Smooth 0.30-0.60 Multi units, attached 0.60-0.75 * Rough 0.20-0.50 Suburban 0.25-0.40 Cultivated rows I * Heavy soil, no crop 0.30-0.60 * Heavy soil, with crop 0.20-0.50 * Sandy soil, no crop 0.20-0.40 * Sandy soil, with crop 0.10-0.25 I Pasture * Heavy soil 0.15-0.45 * Sandy soil 0.05-0.25 I Woodlands 0.05-0.25 Industrial: Streets: Light areas 0.50-0.80 Asphaltic 11111111111. 0.70-0.95 ' 6,, A Heavy areas 0.60-0.90 Concrete 0.80-0.95 CO' O il Brick 0.70-0.85 Parks, cemeteries 0.10-0.25 Unimproved areas 0.10-0.30 I Playgrounds 0.20-0.35 Drives and walks 0.75-0.85 Railroad yard areas 0.20-0.40 Roofs 0.75-0.95 Note: The designer must use judgement to select the appropriate "C" value within the range. Generally, larger areas with permeable soils, flat slopes and dense vegetation should have the lowest C values. Smaller areas with dense soils, moderate to steep slopes, and sparse vegetation should be assigned the highest C values. i Source: American Society of Civil Engineers No V - 29 rr Channel Report Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk,Inc. Thursday,Jul 6 2017 Channel A20 Adequacy and Liner Type Triangular Highlighted Side Slopes (z:1) = 3.00, 3.00 Depth (ft) = 0.33 Total Depth (ft) = 0.75 Q (cfs) = 1.060 Area (sqft) = 0.33 Invert Elev (ft) = 1.00 Velocity (ft/s) = 3.24 Slope (%) = 8.10 Wetted Perim (ft) = 2.09 N-Value = 0.035 Crit Depth, Yc (ft) = 0.38 Top Width (ft) = 1.98 Calculations EGL (ft) = 0.49 "` Compute by: Known Q Known Q (cfs) = 1.06 a Elev (ft) Depth ft( ) Section 2.00 1.00 a 1.75 - 0.75 1.50 0.50 1.25 0.25 1.00 0.00 0.75 -0.25 I 0 .5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 Reach (ft) i 1 i 1 i 1 1 APPENDIX G Storm Drains 1 1 ' 1 U 1 1 i SCS ENGINEERS a Client Project Job No Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108 01 Subject By Date a Storm Drains NTJ 3/13/2017 Checked Date .� Purpose: Establish storm drain size and adequacy for 10 year storm event for drains in Drainage Area A. Given: Reinforced concrete pipe and concrete manhole design. Drainage area to storm drain is deliniated on Drawing 5W2. Assumptions' 1.Manning's number(n)=0.013 2.For hydrualic grade line calculations,HGL set to crown of pipe at discharge point. Calculations 1.See attached dydrotogy cacluations for drainage areas. Peak Flows Drainage Area,A= 9 cfs 2.See attached hydrualic calculations for strom drain hydualic gradient and capacity. Conclusions: The storm drain as designed has adequate capacity to handle the 10-year storm event without causing a pressure situation in the pipes. also the HGL is below ground surface,therefore manholes will not be overtopped. mok 111111 a 1 SCS ENGINEERS I Client Project Job No, Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108.01 I Subject By Date Storm Drains NTJ 3/3/2017 Checked Date i Purpose: Calculate the peak discharge for Drainage Area A for a 10 year event I Given: I 1 Use 10 year storm for design 2 Areas Taken from autocad Drawings SW2 Assumptions: It 1 Use NOM Atlas 14 for intensity 2.TR55 used to find time of concentration 4.Cf value From VDOT Drainage Manual= 1 __ 5 C values taken from page V-29 Table 5-2 of the VESCH. Calculations: Cumulative"C" C=((A1`C1)+(A2*C2)+_,+(An+Cn))/(A1+A2+.._+An) MD Peak Flow 010=C*i*A'Cf Area A=A1+A2+ +An Contributing Drainage Area Area(ac) Assmued C Value Mb Impervious Area 0.56 0.90 Pervious Area 2 50 0.35 II Intensity-assume 5 min duration 6 53 in/hr Total Area: I =lmpervous+Pervious 3 06 acres Cumulative"C" C=((Al"C1)+(A2"C2)+, +(An+Cn))/(A1+A2+_ +An) 0 45 I Peak Discharge,Q10: Q10=Cf ASW1"C"i 9.0 cfs Conclusion: I The peak flow for drainage area A is 9 0 cfs, Use this peak flow for calculating structure sizes I I I I I I 4 1 Soil Map—Albemarle County,Virginia p to P k 705750 705900 705850 705900 705950 706000 706050 38°I'20"N gyp( 38°1'20'N 8 w 1.43F 9 �p ' .e ., o { Y ,D11114., 4 tB O b Aio., yF r. { yh a 11 s p' a q' t k�y{4 , t'S . 141i,'�" gar , ft 4, ya �' s ,-...--„:41,-,N,,,,, ,....fiY° i ri ",, , ,a, ,.. 3,..;i6:11 •„; ",a '116" e } }' /' y Q t'4,..: $;' 5 { xj° xr-. {}' xi x, `wL, m yp .. �• 3) �s l '' t^ ff �¢ . �f'� } +�i It „...,-,,,... 4„,1,I, B1 Y ,--#. ^ if ho, ,1 I g , w,,, „d '4 .1* Ay e ; . Asttri,,,, 4 l' #1t4:;* #4"41-°.41 of- 4,r , It' 04 1'O td �' n § psi 3, 14,' ,' M ^ 1 '377C3t, C3 y 4,,,,,* 4.i$1,-*,4 t, a s 368 k n + a N V Q 38°1'5^N 38°1'S'N 705750 705800 705850 705900 705950 706000 706050 3 ea Map Scale:1:2,160 f printed on A porha t(8.5"x 11")sheet -Meters N o 30 60 120 180 iA — Feet 0 100 200 4Op 600 Map projedbn:Web Merotor Coma coordinates:WGSS4 Edge t cs:1IEM Zone 17N WGS&1 u 01111 Natural Resources Web Soil Survey 7/6/2016 .. Conservation Service National Cooperative Soil Survey Page 1 of 3 I I I I I Soil Map—Albemarle County,Virginia I MAP LEGEND MAP INFORMATION Area of Interest(A01) g Spoil Area The soil surveys that comprise your AOI were mapped at 1:16,800. I Area of Interest(ACMStony Spot f1 Warning:Soil Map may not be valid at this scale. Soils as Very Stony Spot J Soil Map Unit Polygons Enlargement of maps beyond the scale of mapping can cause i Wel Spot% misunderstanding of the detail of mapping and accuracy of soil line „ . Boll Map Unit Lines placement.The maps do not show the small areas of contrasting I A Other soils that could have been shown ata more detailed scale. ® Soil Map Unit Points Special Line Features Special Point Features Please rely on the bar scale on each map sheet for map V Blowout Water Features measurements Streams and Canals ® Borrow Pit - Source of Map: Natural Resources Conservation Service I Transportation Web Soil Survey URL. hlipllwebsoilsurvey.nres,usda.gov X Clay Spot ..+4. Rails Coordinate System'. Web Mercator(EPSG:3657) Q Closed Depression ../ Interstate Highways Maps from the Web Soil Survey are based on the Web Mercator x Gravel Pit US Routes projection,which preserves direction and shape but distorts distance and area.A projection that preserves area,such as the Gravelly Spot Major Roads Albers equal-area conic projection,should be used if more accurate I O Landfill Local Roads calculations of distance or area are required. A. Lava Flow Background This product is generated from the USDA-NRCS certified data as of 9 the version date(s)listed below. a{6 Marsh or swamp . Aerial Photography Soil Survey Area: Albemarle County,Virginia it, Mine or Quarry Survey Area Data: Version 10.Dec 11,2013 I ® Miscellaneous Water Soil map units are labeled(as space allows(formap scales 1:50,000 ® Perennial Water or larger, v r Rock outcrop Date(s)aerial images were photographed: May 9,2011—Jun 4, 2011 1 + I The Saline Spot The orthophoto or other base map on which the soil lines were Sandy Spot compiled and digitized probably differs from the background .p Severely Eroded Spot imagery displayed on these maps.As a result,some minor shifting of map unit boundaries may be evident. O Sinkhole ig, Slide or Slip I p4 Sodic Spot ile USDA Natural Resources Web Soil Survey 716/2016 aillil Conservation Service National Cooperative Soil Survey Page 2 of 3 • UN IS NO OM NM Soil Map—Albemarle County,Virginia MS Map Unit Legend Albemarle County,Virginia(VA003) Map Unit Symbol Map Unit Name Acres in AOi Percent of AOI 1B Abell silt loam,2 to 7 percent 0.0 0.1% slopes 14C Chester loam,7 to 15 percent 1.2 5.3% slopes 198 Cullen loam,2 to 7 percent 8.3 35.9% slopes 20C3 Cullen clay loam,7 to 15 2.0 8.8% percent slopes,severely eroded 20D3 Cullen clay loam,15 to 25 0.0 0.0% percent slopes,severely eroded 368 Hayesville loam,2 to 7 percent 1.6 6.8% slopes 36C Hayesville loam,7 to 15 percent 3.4 15.0% slopes 37C3 Hayesville clay loam,7 to 15 6.0 26.2% percent slopes,severely eroded 37D3 Hayesville clay loam, 15 to 25 0.4 1.9% percent slopes,severely eroded Totals for Area of Interest 23.0 100.0% An/ 01111 AIM USDA Natural Resources Web Soil Survey 7/6/2016 1111 Conservation Service National Cooperative Soil Survey Page 3 of 3 ir. 1992 i Soil name surftex hydgrp kfact wtdepl wtdeph GLENWOOD CB-L B 0.20 6.00 6.00 II GLENWOOD VARIANT RB-L B 0.05 6.00 6.00 GOLDSBORO FSL B 0.20 2.00 3.00 GOLDSBORO SL B 0.20 2.00 3.00 GOLDSTON CN-L C 0.15 6.00 6.00 II GOLDSTON CN-SIL C 0.15 6.00 6.00 GOLDSTON CNV-SIL C 0.05 6.00 6.00 IIGOLDSTON SIL C 0.15 6.00 6.00 GOLDVEIN GRF-SIL C 0.28 1.00 2.00 GOLDVEIN GRITTY GRF-SIL C 0.28 1.00 2.00 GORESVILLE* GR-SIL B 0.24 6.00 6.00 IIGREENLEE STV-L B 0.10 6.00 6.00 GRIMSLEY CB-L B 0.20 6.00 6.00 GRIMSLEY CB-SL B 0.20 6.00 6.00 IIGRIMSLEY ST-L 8 0.20 6.00 6.00 GRIMSLEY STX-L B 0.20 6.00 6.00 GRITNEY FSL C 0.20 6.00 6.00 GRITNEY GR-FSL C 0.15 6.00 6.00 IIGROSECLOSE GR-L C 0.28 6.00 6.00 GROSECLOSE GR-SIL C 0.28 6.00 6.00 GROSECLOSE L C 0.43 6.00 6.00 IIGROSECLOSE SICL C 0.32 6.00 6.00 GROSECLOSE SIL C 0.43 6.00 6.00 GROVER FSL B 0.24 6.00 6.00 GROVER SCL B 0.28 6.00 6.00 GROVER SL B 0.24 6.00 6.00 GUERNSEY SIL C 0.43 1.50 3.00 GULLIED LAND VAR 6.00 6.00 GULLION L C 0.32 1.50 3.00 GULLION SIL C 0.32 1.50 3.00 GUNSTOCK CN-L C 0.37 6.00 6.00 GUNSTOCK SL C 0.28 6.00 6.00 GUYAN SIL C 0.32 0.50 1.50 GWINNETT VARIANT CL B 0.28 6.00 6.00 HAGERSTOWN SIL C 0.32 6.00 6.00 HAGERSTWON SIL C 0.32 6.00 6.00 HALEWOOD L B 0.32 6.00 6.00 HALEWOOD STV-FSL C 0.24 6.00 6.00 HARTLETON CN-L B 0.20 6.00 6.00 HARTLETON STV-L B 0.15 6.00 6.00 HATBORO L D 0.49 0.00 0.50 HATBORO SIL D 0.49 0.00 0.50 HAWKSBILL CB-L B 0.17 6.00 6.00 HAWKSBILL CBV-L B 0.17 6.00 6.00 HAWKSBILL STX-L B 0.17 6.00 6.00 HAYESVILE L B 0.20 6.00 6.00 HAYESVILLE CB-L B 0.20 6.00 6.00 HAYESVILLE CL B 0.20 6.00 6.00 HAYESVILLE CL B 0.24 6.00 6.00 HAYESVILLE FSL 8 0.20 6.00 6.00 HAYESVILLE GR-FSL B 0.20 6.00 6.00 HAYESVILLE L B 0.20 6.00 6.00 HAYESVILLE STV-FSL C 0.15 6.00 6.00 HAYESVILLE STV-L C 0.15 6.00 6.00 VI - 63 1992 Soil name surftex hydgrp kfact wtdepl wtdeph HAYESVILLE STV-L C 0.24 6.00 6.00 HAYESVILLE STV-SCL C 0.32 6.00 6.00 HAYMARKET SIL D 0.32 6.00 6.00 HAYTER CH-L B 0.20 6.00 6.00 HAYTER CBV-L B 0.15 6.00 6.00 HAYTER L B 0.28 6.00 6.00 HAYWOOD L B 0.24 6.00 6.00 HAZEL CN-L C 0.24 6.00 6.00 HAZEL L C 0.32 6.00 6.00 HAZEL SIL C 0.32 6.00 6.00 HAZEL ST-L C 0.24 6.00 6.00 HAZEL STV-L C 0.24 6.00 6.00 HAZEL CHANNERY CN-SIL C 0.32 6.00 6.00 HAZELTON STV-L B 0.15 6.00 6.00 HAZLETON CN-SL B 0.17 6.00 6.00 HAZLETON ST-SL B 0.15 6.00 6.00 HAZLETON STV-SL B 0.15 6.00 6.00 HAZLETON STX-SL B 0.15 6.00 6.00 RN HELENA CL C 0.28 1.50 2.50 HELENA FSL C 0.20 1.50 2.50 II HELENA FSL C 0.24 1.50 2.50 HELENA GR-COBE C 0.15 1.50 2.50 HELENA GRF-FSL C 0.15 1.50 2.50 HELENA L C 0.20 1.50 2.50 IIHELENA L C 0.24 1.50 2.50 HELENA SL C 0.20 1.50 2.50 HELENA SL C 0.24 1.50 2.50 HERNDON L B 0.43 6.00 6.00 HERNDON SICL B 0.49 6.00 6.00 HERNDON SIL B 0.43 6.00 6.00 HERNDON VFSL B 0.43 6.00 6.00 HIWASSEE CB-FSL B 0.28 6.00 6.00 HIWASSEE CB-SL B 0.24 6.00 6.00 HIWASSEE CL B 0.28 6.00 6.00 HIWASSEE FSL B 0.28 6.00 6.00 HIWASSEE GR-L B 0.24 6.00 6.00 HIWASSEE L B 0.28 6.00 6.00 HIWASSEE SIL B 0.32 6.00 6.00 HIWASSEE VARIANT L B 0.32 6.00 6.00 HOADLY L C 0.28 0.50 1.50 HOBUCKEN L D 0.10 HOGELAND* CB-SIL C 0.24 6.00 6.00 II HOLLYWOOD CL D 0.32 6.00 6.00 HUNTINGTON L B 0.28 6.00 6.00 HUNTINGTON SIL B 0.28 6.00 6.00 II HYATTSVILLE FSL B 0.28 4.00 6.00 HYDE SIL B/D 0.17 0.00 1.50 HYDRAQUENTS SL B 0.37 4.00 6.00 II HYDRAQUENTS SL D 0.37 INGLEDOVE L B 0.32 6.00 6.00 IREDELL CL C/D 0.32 1.00 2.00 IREDELL FSL C/D 0.28 1.00 2.00 IREDELL L C/D 0.32 1.00 2.00 II IREDELL SIL C/D 0.32 1.00 2.00 IIVI - 64 II 1992 i Soil name eurftex hydgrp kfact wtdepl wtdeph CATOCTIN STX-SIL C 0.20 6.00 6.00 II CATPOINT FS A 0.10 4.00 6.00 CATPOINT LS A 0.10 4.00 6.00 CAVERNS SL B 0.20 6.00 6.00 , CECIL CB-FSL B 0.28 6.00 6.00 CECIL CL B 0.24 6.00 6.00 CECIL CL B 0.28 6.00 6.00 IICECIL FSL B 0.20 6.00 6.00 CECIL FSL B 0.28 6.00 6.00 CECIL GR-FSL B 0.15 6.00 6.00 CECIL GR-SL B 0.15 6.00 6.00 II CECIL GRF-SL B 0.28 6.00 6.00 CECIL L B 0.28 6.00 6.00 CECIL SCL $ 0.28 6.00 6.00 IICECIL SL B 0.28 6.00 6.00 CECIL VFSL B 0.28 6.00 6.00 CHAGRIN FSL B 0.32 4.00 6.00 CHAGRIN L B 0.32 4.00 6.00 I CHAGRIN SIL B 0.32 4.00 6.00 CHAGRIN VARIANT LS A 0.10 6.00 6.00 CHAPANOKE SIL C 0.43 0.50 1.50 IICHASTAIN L D 0.32 0.00 1.00 CHASTAIN SICL D 0.32 0.00 1.00 CHASTAIN SIL D 0.32 0.00 1.00 CHATUGE L D 0.32 1.00 2.00 IICHATUGE SL D 0.32 1.00 2.00 CHAVIES FSL B 0.24 6.00 6.00 CHAVIES SL B 0.24 6.00 6.00 CHAVIES VARIANT SL B 0.24 3.50 3.50 IICHENNEBY L C 0.37 1.00 2.50 CHENNEBY SIL C 0.37 1.00 2.50 CHESTER CB-L B 0.32 6.00 6.00 IICHESTER CN-L B 0.28 6.00 6.00 CHESTER L B 0.32 6.00 6.00 CHESTER SIL B 0.32 6.00 6.00 CHESTER SL B 0.32 6.00 6.00 I CHESTER STV-L B 0.24 5.00 5.00 CHESTER STV-L B 0.32 5.00 5.00 CHESTER LOAM L B 0.32 6.00 6.00 CHEWACLA FSL C 0.24 0.50 1.50 CHEWACLA L C 0.28 0.50 1.50 CHEWACLA L C 0.49 1.00 2.00 CHEWACLA SIL C 0.28 0.50 1.50 CHEWACLA SIL C 0.49 1.00 2.00 CHICKAHOMINY L D 0.37 CHICKAHOMINY L D 0.37 0.00 0.50 CHICKAHOMINY SIL D 0.37 0.00 0.50 CHILHOWIE C C 0.37 6.00 6.00 CHILHOWIE CN-SICL C 0.20 6.00 6.00 CHILHOWIE CN-SICL C 0.37 6.00 6.00 CHILHOWIE SIC C 0.37 6.00 6.00 CHILHOWIE SICL C 0.37 6.00 6.00 CHINCOTEAGUE SIL D 0.32 CHIPLEY S C 0.10 2.00 3.00 VI - 56 1992 Soil name surftex hydgrp kfact wtdepl wtdeph COTACO CB-FSL C 0.24 1.50 2.50 COTACO FSL C 0.37 1.50 2.50 COTACO L C 0.37 1.50 2.50 COTACO SIL C 0.37 1.50 2.50 COTACO VARIANT CB-L C 0.24 2.00 3.00 COTACO VARIANT SIL C 0.43 2.00 3.00 COURSEY L C 0.32 2.00 3.00 COWEE CH-L 8 0.20 6.00 6.00 COXVILLE FSL D 0.24 0.00 1.50 COXVILLE L D 0.24 0.00 1.50 CRAIGSVILLE CB-FSL B 0.28 6.00 6.00 CRAIGSVILLE CB-SL B 0.20 6.00 6.00 CRAIGSVILLE CB-SL B 0.28 6.00 6.00 CRAIGSVILLE CBV-L P 0.10 6.00 6.00 II CRAIGSVILLE GR-FSL B 0.17 6.00 6.00 CRAIGSVILLE L B 0.28 6.00 6.00 CRAIGSVILLE SL B 0.17 6.00 6.00 II CRAVEN CL C 0.37 2.00 3.00 CRAVEN FSL C 0.32 2.00 3.00 CRAVEN L C 0.32 2.00 3.00 II CRAVEN SCL C 0.37 2.00 3.00 CRAVEN SIL C 0.32 2.00 3.00 CREEDMOOR FSL C 0.28 1.50 2.00 CREEDMOOR GR-FSL C 0.26 1.50 2.00 CREEDMOOR GRV-SL C 0.28 1.50 2.00 ■ 11 CREEDMOOR L C 0.28 1.50 2.00 CREEDMOOR SL C 0.28 1.50 2.00 CREEDMOOR VARIANT FSL C 0.37 0.50 1.50 CREEDMORE FSL C 0.28 1.50 2.00 ■ el CROTON SIL D 0.37 0.00 1.50 CROTON SIL D 0.43 0.00 0.50 CULLEN CL C 0.24 6.00 6.00 CULLEN L C 0.37 6.00 6.00 CULPEPER CL C 0.37 6.00 6.00 CULPEPER FSL C 0.37 6.00 6.00 CULPEPER L C 0.37 6.00 6.00 II DALEVILLE L D 0.32 0.00 1.00 DALEVILLE SIL D 0.32 0.00 1.00 II DANDRIDGE SH-BICC D 0.17 6.00 6.00 DAVIDSON C B 0.28 6.00 6.00 DAVIDSON CL B 0.24 6.00 6.00 DAVIDSON CL B 0.28 6.00 6.00 II DAVIDSON CL B 0.37 6.00 6.00 DAVIDSON ST-CL B 0.20 6.00 6.00 DAWHOO VARIANT FSL 0.17 II DECATUR CL B 0.32 6.00 6.00 DEKALB CB-FSL C 0.17 6.00 6.00 DEKALB CB-L C 0.17 6.00 6.00 DEKALB CB-SL C 0.17 6.00 6.00 II DEKALB DEKALB CN-FSL C 0.17 6.00 6.00 CN-L C 0.17 6.00 6.00 DEKALB CN-SL C 0.17 6.00 6.00 DEKALB FSL C 0.24 6.00 6.00 DEKALB RB-FSL C 0.17 6.00 6.00 VI - 58 I 1992 1 TABLE 5-2 VALUES OF RUNOFF COEFFICIENT (C) FOR RATIONAL FORMULA III I Land Use C Land Use C Business: Lawns: Downtown areas 0.70-0.95 Sandy soil, flat, 2% 0.05-0.10 I Neighborhood areas 0.50-0.70 Sandy soil, average, 2-7% 0.10-0.15 Sandy soil, steep, 7% 0.15-0.20 Heavy soil, flat, 2% 0.13-0.17 Heavy soil, average, 2-7% 0.18-0.22 I Heavy soil, steep, 7% 0.25-0.35 �)S(; o.3' Residential: Agricultural land: Single-family areas 0.30-0.50 Bare packed soil Multi units, detached 0.40-0.60 * Smooth 0.30-0.60 Multi units, attached 0.60-0.75 * Rough 0.20-0.50 Suburban 0.25-0.40 Cultivated rows * Heavy soil, no crop 0.30-0.60 * Heavy soil, with crop 0.20-0.50 * Sandy soil, no crop 0.20-0.40 * Sandy soil, with crop 0.10-0.25 I Pasture * Heavy soil 0.15-0.45 * Sandy soil 0.05-0.25 I Woodlands 0.05-0.25 Industrial: Streets: Light areas 0.50-0.80 Asphaltic 0.70-0.95 UsG Heavy areas 0.60-0.90 Concrete 0.80-0.95 0'1° Brick 0.70-0.85 ow Parks, cemeteries 0.10-0.25 Unimproved areas 0.10-0.30 Playgrounds 0.20-0.35 Drives and walks 0.75-0.85 •' Railroad yard areas 0.20-0.40 Roofs 0.75-0.95 WI Note: The designer must use judgement to select the appropriate "C" value within the range. Generally, larger areas with permeable soils, flat slopes and dense vegetation should have the lowest C values. Smaller areas with dense soils, MI moderate to steep slopes, and sparse vegetation should be assigned the highest C values. Source: American Society of Civil Engineers US IIIg V - 29 Precipitation Frequency Data Server Page 1 of 4 .. NOAA Atlas 14,Volume 2,Version 3 Location name:Charlottesville,Virginia,USA* Latitude:38.0253°.Longitude:-78.6538° e>• Elevation:662.27 ft** f ? �w ��ttt••• ,Ar 'source ESP,!Maps .` "source.USGS POINT PRECIPITATION FREQUENCY ESTIMATES G M.Bonnie,D Martin,B.Lin,T Parzybok,M Yekla,and D.Riley Am NOA.A,National Weather Service,Silver Spring,Maryland PF tabular I PF graphical I Maps & aerials PF tabular PDS-based point precipitation frequency estimates with 90%confidence intervals(in inches/hour)1 _� Average recurrence interval(years) I Duration 1 2 .I 5 I1 10 J 25 50 100 200 500 1000 5-min 4.12 4.92 6.80 6.63 7.37 8.02 8,63 9.20 9.90 -r 10.6 (3.72-4.57) (4.45.5.45) (5.23-6.41) (5.88-7.21) (6.60-8.11) (7.15-8.83)iL(7.64-9.52))1(8.09.10.2) (8.60-11.0) (9.00-11,7) 10-min 3.29 3.94 4.64 5.22 5.87 6.38 6.86 7.30 7.83 ( 6.24 (2.96.3.65) (3.55.4.36) (4.19-5.13) ;(4.705.76) (5.26-6.47) I(5.69-7.03i I (6.08-7.56) (641-8.06) (6.80-8.69) I (709-919) +. 15-min 2.74 I 3,30 3,92 I 4.40 4.96 6,39 I 6,78 6.14 6.57 6.90 (2.46.3.04) ((2.99-3,65)1 (3.54-4.32) (397 .880 (4.45-5.46) (4.80-5.94)�t (5.12-6.37) (5.40-6.78) (5.71-7.29), (5.93-7.69) 30-min 1.88 2.28 2.78 3.19 3.67 4.06 4.42 4.78 5.23 6.59 (1.70.2.08) (2.06-2.52) (2.51-3.07) (2.87.3.52) (3.29.4.05) (3.62-4.47)1 (3.92-4.88) (4.20-5.28) (4.54-5.80) (4.80-6.23) 60•min 1.17 1.43 1.78 2.08 2.46 2.76 3.06 3.35 3.75 4.08 (1.06-1.30) (1.25-1.58) (1.61-1.97) (1.87-2.29) (2.19.2.70) (2.45.3.03) (2.70.3.36) (2.953..70) (3.26-4.16) (3.51-4.55) 2-hr 0.700 0.862 1.07 1.26 1.60 1.70 1.91 2.12 2.42 2.67 !(0.622.0.792)(0.756-0.961) (0.948-1.20) (1.12-1.411 (1.32.1.68) (1.49-1.91) (1.66-2.141 (1.83_2.38) (2-06-2.73) (2,25;3.02) 3-hr 0.511 0.621 0.778 0.914 1.09 1.24 1.39 1.55 1.77 1.96 (0.454-0.582) (0.549.0.705)(0.687.0.884) (0.805.1.04) (0.956-1.23) (1.08.1.40) (1.21-1.58) (1.33.1 76) (1.50.2.02) (1 64-2 24) J Air 0.331 0.401 0.498 0.687 0.706 0.809 0.918 1.04 1.20 (I 1,35 (0.296.0.374)(0 357.0.452 (0.442-0561)((0.518.0.660)(0.619-0.793)(0.704-0.908)1(0.791-103) (0.882.1 17)) (1.01-1.36)II (1.12-1.53) 12-hr 0.209 0.262 0.316 0.372 0.453 0.525 0.603 0.689 0.817 0.932 (0.186.0.238) (0.224.0.288)(0.278.0.358);(0.328.0.423)(0.396-0.514)(0.453.0.595)-(0.514.0.684)(0.579.0.782)(0.671.0.931) (0.753-1 07) 24-hr 0.127 0.164 0.196 0.231 0.284 0.329 0.378 0.433 0.614 0.583 r (0.114-0 1421!)0.138-0.172j�((0 176-0.219)!1(0.207.0.258)(0.252.0.316)(0.289.0.365)(0.330.0.420)(0.374.0.479)(0.436.0.570)(0.488.0.647)) 2-da 0.075 0.091 0.116 0.136 0.164 0.188 0.216 0.243 0.285 0.320 y (0.067-0.0831(0.081-0.101�((b.103-0.12811(0121-0.151)l�(0.146.0.163) 0.166.0.2091(0188.0.239}(0.211.0.271){0.244-0.318}(0.271-0.358)1 3-day 0.063 0.064 .082 0.096 0.116 0.133 0.162 0.172 0.201 0.226 (0.048.0.059) (0.058.0.071)( 0 0.074.0.090) (0.066.0.106)(0.104-0.128)(0.119-0.147)(0 134-0.168)(0.151.0.190)'(0.174.0.223)(0.193-0.251) - 4-day 0,042 0.051 0.066 I 0.076 0.092 0.106 0,120 0.136 0.169 0.178 l (0.039-0.047) �j0.047.0.056)(0.059-0.072),(0.069.0.084)(0.083-0.101),(0.095-0.116)(0.107.0.132 (0.120.0.150)(0.139-0.175)(D.154-0.197)1 7-day 0.028 0.034 0.042 0.049 0.059 0.067 0.076 0.085 0.098 0.109 (0.026.1.031) (0.031.0.0371(0.039-0.046) (0045.0.053)(0.053-0.064)(0.060.0,073)(0.068-0.0831(0.075.0.093)(0.086.0.108)(0.095-0.120) .ere 10-day 0.022 ,`� 0.027 0.033 0.038 0.045 0.061 0.067 0.063 0.072 0.079 (0.020-0.02) (0.025-0.029) (0.030-0.036)[{0.035.0041)(0.041.0.049)(0.046.0,055)(0.051.0.061)(0.057.0.068)(0.064.0.078)(0.070-0.086) 0.015 0.017 0.021 0.024 0.028 0.031 0.034 _ 0.037 0.041 ( 0.044 20-day (0.014.0.016)(0.016-0.019)(0.020-0.023)(0.022-0.026) (0.026-0.030)(0.028.0.033)(0.031.0.036)(0.034.0.040)(0.037.0.044)10.04041048)1 �- 0.012 0.014 0.017 0.019 0.021 0,023 0.025 0.027 0.029 0.031 30-day (0.011-0.013)(0.013-0.015)(0.016-0.018)(0,017-0.020) (0.020-0.023)(0.022.0.025)(0.023.0.027)(0.025.0.029)(0.027.0.031)(0.029-0 033) L 45-day 0.010 0.012 0.014 0.016 0.017 0.018 0.020 0.021 0.023 0.024 (0.009-0.011)r0-.011-0.0121110.013-0.015)((0.014-0.016)(0.016-0.018)(0.01 7-0 020)((0 018-0.0211) 0 020-0.022)1(0.021-0.024){0.022-0.026)1 60-day ( 0.009 ) 0.010 )11. 0.012 ) 0.013 i 0.014 1 0.016 0.017 1 0.018 )r 0,019 II 0.020 )I 0 008-0.009 (0.010-0.011 I`(0.011-0,013 0.012-0.014)(0.014-0.015)(0,015-0.016) (0.016-0.018 ((0.016-0.019)!!(0.018-0.020)(0.018-0.021 - 'Precipitation frequency(PF)estimates in this table are based on frequency analysis of portal duration series(PDS). Numbers in parenthesis are PF estimates at lower and upper bounds of the 90%confidence interval The probability that precipitation frequency estimates (for a given duration and average recurrence interval)will be greater than the upper bound(or less than the lower bound)is 5%.Estimates al upper bounds are not checked against probable maximum precipitation(PMP)estimates and may be higher than currently valid PMP values. Please refer to NOAA Atlas 14 document for more information. Back to Top s http://hdsc.nws-noaa.gov/hdsc/pfds/pfds_printpage,html?Iat=38.0253&Ion=-78.6538&dat... 11/21/2016 o 0 T ; m CO N a o I 7 o. 0 >. L a) a) U) F- MI al m W a) C .. G J Z W r O C 7 J v o m c oN- _ � N- N- 0 111 C N^ N M CO M O U) 0) N 4 G,^. p a- O C f 2= ` rt` t ._.. - V) 00 .15 J 3 rn r oo z 0 o m rt• 0 a a) 0 0) C _o e o r to co • 0 n CO t a ao a 0 a)M rno 0w$ CO r ti O M r t- t c ae o pj O 00) C J O N co W i Lo .0 O CO 01 O C C ^ _M J .... 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N- CO (1) It •.... c am I --_ 15 e a = cc• I N- 2 0. 113 T 0 Q IN I C7 CT C7 C7 CI CT Vin M O b O O 0 O 0 N . T N I EN — C7 PM (D j (0 C N a to CO N LL = ori ct- rsi re Z' (7-) N w —f c j ' v I rn Cr)1 C34-4 C N- c ti c _ m _ O O W 0 Z C• O r VCL AV 0 ` O � I + I - �d C $ O O a ...I- ,- C O = v IN0 IIr N I m I O / I r. to Q V r , N M I I . a • o CO Q a coN- ^ a) i M (yd W li43) N �� O i O ppI a U ,' 0- OQ O O O Q N a IN IT.:ai t�� LO CT totQ7 N * M O a) a I I SCS ENGINEERS ' Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216106 01 Subject By Date Storm Drains NTJ 3/13/2017 Checked Date Establish storm drain size and adequacy for 10 year storm event for drains in Drainage Area B. ' Purpose: q Y Given: Reinforced concrete pipe and concrete manhole design. Drainage area to storm drain is deliniated on Drawing SW2. ASSUmpiions: 1.Manning's number(n)=0.013 2.For hydrualic grade line calculations,HGL set to crown of pipe at discharge point. Calculations: 1.See attached dydrology cacluations for drainage areas. Peak Flows Drainage Area,A= 5.23 cfs 2.See attached hydrualic calculations for strom drain hydualic gradient and capacity. Conclusions: The storm drain as designed has adequate capacity to handle the 10-year storm event without causing a pressure situation in the pipes. also the HGL is below ground surface,therefore manholes will not be overtopped. IA I 1 1 3 a SCS ENGINEERS Client Project Job No Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station _02216108.01 Subject By Date • Storm Drains NTJ 3/3/2017 Checked Date +� Purpose: Calculate the peak discharge and storm structure size for pipes in Drainage Area B for a 10 year event Given: 1 Use 10 year storm for design 2 Areas Taken from autocad Drawings SW2 Assumptions: 1 Use NOAA Atlas 14 for intensity 2 TR55 used to find time of concentration mos 4.Cf value From VDOT Drainage Manual= 1 5.C values taken from page V-29 Table 5-2 of the VESCH. Calculations: a Cumulative"C" C=((A1*C1)+(A2"C2)+ ,+(An+Cn))/(A1+A2+_.,+An) Peak Flow Q10=C*A*Cf Area A=A1+A2+...+An Contributing Drainage Area Area(ac) Assmued C Value Impervious Area 0,68 0 90 Pervious Area 0 54 0 35 ▪ Intensity-assume 5 min duration 6 53 in/hr Total Area: =lmpervous+Pervious 1.22 acres sist Cumulative"C" C=((A1*C1)+(A2*C2)+...+(An+Cn))/(A1+A2+_.+An) 0.66 • Peak Discharge,Q10: Q10=CPA'C1 5.2 cfs Conclusion: ▪ The peak flow for drainage area b is 5 2 cfs Use this peak flow for sizing storm structures in this area, MIN rr MINI 1 s Soil Map—Albemarle County,Virginia N to A IR 705750 705800 745850 765900 705950 706000 706050 38°1'20"N I 38°I'20"N rye{ >, . gg�{ • ..._. , _ ,.., i, ;.i II 1 ci ill. i '36B :-.1i,/ `r Cts t 3 J - �- y .., % , .1.,,,s. r , ..._'8 , .- -44-0,„, 'd. 4''' - A , 0 , __.„.......; .. .. , . ,,..".._„ , -. - , , ..... -01-- - ‘,, ___ - _ _,.......... , ..„ , i ... . ........ . t .. ...._...... .._ ... , i ‘r,..ir. „ -,..„ , i,- ... . , ,. -,,,, , i ,, / , „.„ _ 1 ,. :,,,, �8 �� r' f/ ��• �� t a ,:.„ 37.C3 20C s *" .. 37D3 v f v f -- � ° 368 36( � a a 38°1 5.1N I 39°1'S"N 705750 705803 705850 705900 705950 706030 706050 3 3 to M Scale:1:2,16(1 if rinted on A rt ait(8.5"x 11')sheet. i Map P Metas '0 N 0".. ."3---0 60 120 180 A ---- Feet 0 100 200 600 Map projection:Web Mercator Comer WGS84 Edge tics:UfM Zone 17N WGS84 I USDA Natural Resources Web Soil Survey 7/6/2016 5" Conservation Service National Cooperative Soil Survey Page 1 of 3 E INN NIB Soil Map—Albemarle County,Virginia MAP LEGEND MAP INFORMATION Area of Interest(Aol) Spoil Area The soil surveys that comprise your AOI were mapped at 1:15,800. U Area of Interest(AOI) id a 4Stony Spot Warning:Soil Map may not be valid at this scale. Sells Very Stony Spot jj Soil Map Unit Polygons Enlargement of maps beyond the scale of mapping can cause e Wet Spot misunderstanding of the detail of mapping and accuracy of sad line ,-✓ Soil Map Unit Lines placement.The maps do not show the small areas of contrasting ;,, other soils that could have been shown at a more detailed scale. 8 Soil Map Unit Points •• Special Line Features --._......_.___.__...___._ .___.,...,,...„.. Special Point Features Please rely on the bar scale on each map sheet for map V Water Features Blowout measurements. _ Streams and Canals ® Borrow Pit Source of Map: Natural Resources Conservation Service Transportation Web Soil Survey URL. hbp://websoilsurvey.nres.usda.gov 31/4 Clay Spot f+4 Rails Coordinate System: Web Mercator(EPSG:3857) ` Closed Depression ,y Interstate Highways Maps from the Web Soil Survey are based an the Web Mercator X Gravel Pit US Routes projection,which preserves direction and shape but distorts Gravelly Spot distance and area A projection that preserves area,such as the Major Roads Albers equal-area conic projection,should be used if more accurate O Landfill Local Roads calculations of distance or area are required. A Lava Flow Back round This product is generated from the USDA-NR CS certified data as of g the version date(s)listed below. 46 Marsh or swamp . Aerial Photography Mine or Quarry Soil Survey Area: Albemarle Courtly,Virginia Survey Area Data: Version 10,Dec 11,2D13 Mal • Miscellaneous Water Soil map units are labeled(as space allows)for map scales 1:50,000 • Perennial Water or larger. �,. Rock Outcrop Date(s)aerial images were photographed: May 9,2011—Jun 4, 2011 + Saline Spot Sandy Spot The onhopholo or other base map on which the soil lines were icompiled and digitized probably differs from the background g Severely Eroded Spot imagery displayed on these maps.As a result,some minor shifting of map unit boundaries may be evident ® Sinkhole 0 Slide or Slip r♦ Sodic Spot USDA Natural Resources Web Soil Survey 7/612016 ryi Conservation Service National Cooperative Soil Survey Page 2 of 3 — I 1 i Soil Map—Albemarle County,Virginia ' Map Unit Legend Albemarle County,Virginia(VA003) Map Unit Symbol Map Unit Name Acres In AOl Percent of AOI 113 Abell silt loam,2 to 7 percent 0.0 0.1% slopes 14C Chester loam,7 to 15 percent 1.2 5.3% slopes 198 Cullen loam,2 to 7 percent 8.3 35.9% slopes 20C3 Cullen clay loam,7 to 15 2.0 8.8% percent slopes,severely eroded 20D3 Cullen clay loam,15 to 25 0.0 0.0% percent slopes,severely eroded 3613 Hayesville loam,2 to 7 percent 1.6 6.8% slopes 36C Hayesville loam,7 to 15 percent 3.4 15.0% slopes 37C3 Hayesville clay loam,7 to 15 6.0 26.2% percent slopes,severely eroded 37D3 Hayesville clay loam,15 to 25 0.4 1.9% percent slopes,severely eroded Totals for Area of Interest 23.0 100.0% IR ea • ■1 Yr NM Web Soil Survey 7/6/2016 21111 USDA Natural Resources Page 3 of 3 Conservation Service National Cooperative Soil Survey 1992 Soil name surftex hydgrp kfact wtdepl wtdeph GLENWOOD CB-L B 0.20 6.00 6.00 GLENWOOD VARIANT RB-L B 0.05 6.00 6.00 GOLDSBORO FSL B 0.20 2.00 3.00 GOLDSBORO SL B 0.20 2.00 3.00 GOLDSTON CN-L C 0.15 6.00 6.00 GOLDSTON CN-SIL C 0.15 6.00 6.00 GOLDSTON CNV-SIL C 0.05 6.00 6.00 GOLDSTON SIL C 0.15 6.00 6.00 GOLDVEIN GRF-SIL C 0.28 1.00 2.00 GOLDVEIN GRITTY GRF-SIL C 0.28 1.00 2.00 GORESVILLE* GR-SIL B 0.24 6.00 6.00 GREENLEE STV-L B 0.10 6.00 6.00 GRIMSLEY CB-L B 0.20 6.00 6.00 GRIMSLEY CB-SL B 0.20 6.00 6.00 GRIMSLEY ST-L B 0.20 6.00 6.00 GRIMSLEY STX-L B 0.20 6.00 6.00 GRITNEY FSL C 0.20 6.00 6.00 GRITNEY GR-FSL C 0.15 6.00 6.00 GROSECLOSE GR-L C 0.28 6.00 6.00 GROSECLOSE GR-SIL C 0.28 6.00 6.00 GROSECLOSE L C 0.43 6.00 6.00 GROSECLOSE SICL C 0.32 6.00 6.00 GROSECLOSE SIL C 0.43 6.00 6.00 GROVER FSL B 0.24 6.00 6.00 GROVER SCL B 0.28 6.00 6.00 GROVER SL B 0.24 6.00 6.00 GUERNSEY SIL C 0.43 1.50 3.00 GULLIED LAND VAR 6.00 6.00 GULLION L C 0.32 1.50 3.00 GULLION SIL C 0.32 1.50 3.00 GUNSTOCK CN-L C 0.37 6.00 6.00 GUNSTOCK SL C 0.28 6.00 6.00 GUYAN SIL C 0.32 0.50 1.50 GWINNETT VARIANT CL B 0.28 6.00 6.00 HAGERSTOWN SIL C 0.32 6.00 6.00 HAGERSTWON SIL C 0.32 6.00 6.00 HALEWOOD L B 0.32 6.00 6.00 HALEWOOD STV-FSL C 0.24 6.00 6.00 HARTLETON CN-L B 0.20 6.00 6.00 HARTLETON STV-L B 0.15 6.00 6.00 HATBORO L D 0.49 0.00 0.50 HATBORO SIL D 0.49 0.00 0.50 HAWKSBILL CB-L B 0.17 6.00 6.00 HAWKSBILL CBV-L B 0.17 6.00 6.00 HAWKSBILL STX-L B 0.17 6.00 6.00 HAYESVILE L B 0.20 6.00 6.00 HAYESVILLE CB-L B 0.20 6.00 6.00 HAYESVILLE CL B 0.20 6.00 6.00 HAYESVILLE CL B 0.24 6.00 6.00 HAYESVILLE FSL B 0.20 6.00 6.00 HAYESVILLE GR-FSL 8 0.20 6.00 6.00 HAYESVILLE L B 0.20 6.00 6.00 HAYESVILLE STV-FSL C 0.15 6.00 6.00 HAYESVILLE STV-L C 0.15 6.00 6.00 VI - 63 I 1992 I Soil name surftex hydgrp kfact wtdepl wtdeph II HAYESVILLE STV-L C 0.24 6.00 6.00 HAYESVILLE STV-SCL C 0.32 6.00 i 6.00 HAYMARKET SIL D 0.32 6.00 6.00 IIHAYTER CB-L B 0.20 6.00 6.00 HAYTER CBV-L B 0.15 6.00 6.00 HAYTER L B 0.28 6.00 6.00 HAYWOOD L B 0.24 6.00 6.00 II CN-L C 0.24 6.00 6.00 HAZEL L C 0.32 6.00 6.00 HAZEL SIL C 0.32 6.00 6.00 IIHAZEL ST-L C 0.24 6.00 6.00 HAZEL STV-L C 0.24 6.00 6.00 HAZEL CHANNERY CN-SIL C 0.32 6.00 6.00 HAZELTON STV-L B 0.15 6.00 6.00 IIHAZLETON CN-SL B 0.17 6.00 6.00 HAZLETON ST-SL B 0.15 6.00 6.00 HAZLETON STV-SL B 0.15 6.00 6.00 HAZLETON STX-SL B 0.15 6.00 6.00 HELENA CL C 0.28 1.50 2.50 II HELENA FSL C 0.20 1.50 2.50 HELENA FSL C 0.24 1.50 2.50 HELENA GR-COSL C 0.15 1.50 2.50 HELENA GRF-FSL C 0.15 1.50 2.50 HELENA L C 0.20 1.50 2.50 I HELENA L C 0.24 1.50 2.50 HELENA SL C 0.20 1.50 2.50 HELENA SL C 0.24 1.50 2.50 HERNDON L B 0.43 6.00 6.00 11HERNDON SICL B 0.49 6.00 6.00 HERNDON SIL B 0.43 6.00 6.00 HERNDON VFSL B 0.43 6.00 6.00 HIWASSEE CB-FSL B 0.28 6.00 6.00 II HIWASSEE CB-SL 3 0.24 6.00 6.00 HIWASSEE CL B 0.28 6.00 6.00 HIWASSEE FSL B 0.28 6.00 6.00 HIWASSEE GR-L B 0.24 6.00 6.00 II HIWASSEE L B 0.28 6.00 6.00 HIWASSEE SIL B 0.32 6.00 6.00 HIWASSEE VARIANT L B 0.32 6.00 6.00 HOADLY L C 0.28 0.50 1.50 II HOBUCKEN L D 0.10 HOGELAND* CB-SIL C 0.24 6.00 6.00 HOLLYWOOD CL D 0.32 6.00 6.00 HUNTINGTON L B 0.28 6.00 6.00 HUNTINGTON SIL B 0.28 6.00 6.00 HYATTSVILLE FSL B 0.28 4.00 6.00 HYDE SIL B/D 0.17 0.00 1.50 HYDRAQUENTS SL B 0.37 4.00 6.00 HYDRAQUENTS SL D 0.37 INGLEDOVE L B 0.32 6.00 6.00 IREDELL CL C/D 0.32 1.00 2.00 IREDELL FSL C/D 0.28 1.00 2.00 IREDELL L C/D 0.32 1.00 2.00 IREDELL SIL C/D 0.32 1.00 2.00 VI - 64 1992 Soil name surftex hydgrp kfact wtdepl wtdeph 6 CATOCTIN STX-SIL C 0.20 6.00 6.00 CATPOINT FS A 0.10 4.00 6.00 II CATPOINT LS A 0.10 4.00 6.00 CAVERNS SL B 0.20 6.00 6.00 CECIL CB-FSL B 0.28 6.00 6.00 CECIL CL B 0.24 6.00 6.00 II CECIL CL B 0.28 6.00 6.00 CECIL FSL B 0.20 6.00 6.00 CECIL FSL B 0.28 6.00 6.00 ® CECIL GR-FSL B B 0.15 6.00 6.00 CECIL GR-SL 0.15 6.00 6.00 CECIL GRF-SL B 0.28 6.00 6.00 CECIL L B 0.28 6.00 6.00 II CECIL SCL 0.28 6.00 6.00 CECIL SL B 0.28 6.00 6.00 CECIL VFSL B 0.28 6.00 6.00 II CHAGRIN FSL B 0.32 4.00 6.00 CHAGRIN L B 0.32 4.00 6.00 CHAGRIN SIL B 0.32 4.00 6.00 CHAGRIN VARIANT LS A 0.10 6.00 6.00 II CHAPANOKE SIL C 0.43 0.50 1.50 CHASTAIN L D 0.32 0.00 1.00 CHASTAIN SICL D 0.32 0.00 1.00 CHASTAIN SIL D 0.32 0.00 1.00 II CHATUGE L D 0.32 1.00 2.00 CHATUGE SL D 0.32 1.00 2.00 CHAVIES FSL B 0.24 6.00 6.00 CHAVIES SL B 0.24 6.00 6.00 CHAVIES VARIANT SL B 0.24 3.50 3.50 i IN CHENNEBY L C 0.37 1.00 2.50 CHENNEBY SIL C 0.37 1.00 2.50 li CHESTER CB-L B 0.32 6.00 6.00 CHESTER CN-L B 0.28 6.00 6.00 CHESTER L B 0.32 6.00 6.00 CHESTER SIL B 0.32 6.00 6.00 ® CHESTER SL B 0.32 6.00 6.00 CHESTER STV-L B 0.24 5.00 5.00 CHESTER STV-L B 0.32 5.00 5.00 II CHESTER LOAM e; L 8 0.32 6.00 6.00 CHEWACLA FSL C 0.24 0.50 1.50 CHEWACLA L C 0.28 0.50 1.50 II CHEWACLA L C 0.49 1.00 2.00 CHEWACLA SIL C 0.28 0.50 1.50 CHEWACLA SIL C 0.49 1.00 2.00 CHICKAHOMINY L D 0.37 CHICKAHOMINY L D 0.37 0.00 0.50 1 ii CHICKAHOMINY SIL D 0.37 0.00 0.50 CHILHOWIE C C 0.37 6.00 6.00 CHILHOWIE CN-SICL C 0.20 6.00 6.00 1 0 CHILHOWIE CN-SICL C 0.37 6.00 6.00 CHILHOWIE SIC C 0.37 6.00 6.00 CHILHOWIE SICL C 0.37 6.00 6.00 II CHINCOTEAGUE SIL D 0.32 CHIPLEY S C 0.10 2.00 3.00 I VI - 56 II 1992 i Soil name surftex hydgrp kfact wtdepl wtdeph COTACO CB-FSL C 0.24 1.50 2.50 II COTACO FSL C 0.37 1.50 2.50 COTACO L C 0.37 1.50 2.50 COTACO SIL C 0.37 1.50 2.50 II VARIANT CB-L C 0.24 2.00 3.00 COTACO VARIANT SIL C 0.43 2.00 3.00 COURSEY L C 0.32 2.00 3.00 IICOWEE CH-L B 0.20 6.00 6.00 COXVILLE FSL D 0.24 0.00 1.50 COXVILLE L D 0.24 0.00 1.50 CRAIGSVILLE CB-FSL B 0.28 6.00 6.00 II CB-SL B 0.20 6.00 6.00 CRAIGSVILLE CB-SL B 0.28 6.00 6.00 CRAIGSVILLE CBV-L 0 0.10 6.00 6.00 IICRAIGSVILLE GR-FSL B 0.17 6.00 6.00 CRAIGSVILLE L B 0.28 6.00 6.00 CRAIGSVILLE SL B 0.17 6.00 6.00 CRAVEN CL C 0.37 2.00 3.00 CRAVEN FSL C 0.32 2.00 3.00 CRAVEN L C 0.32 2.00 3.00 CRAVEN SCL C 0.37 2.00 3.00 CRAVEN SIL C 0.32 2.00 3.00 CREEDMOOR FSL C 0.28 1.50 2.00 110 CREEDMOOR GR-FSL C 0.28 1.50 2.00 CREEDMOOR GRV-SL C 0.28 1.50 2.00 I CREEDMOOR L C 0.28 1.50 2.00 CREEDMOOR SL C 0.28 1.50 2.00 CREEDMOOR VARIANT FSL C 0.37 0.50 1.50 CREEDMORE FSL C 0.28 1.50 2.00 II CROTON SIL D 0.37 0.00 1.50 CROTON SIL D 0.43 0.00 0.50 CULLEN CL C 0.24 6.00 6.00 CULLEN L C 0.37 6.00 6.00 CULPEPER CL C 0.37 6.00 6.00 kr CULPEPER FSL C 0.37 6.00 6.00 CULPEPER L C 0.37 6.00 6.00 II L D 0.32 0.00 1.00 DALEVILLE SIL D 0.32 0.00 1.00 DANDRIDGE SH-SICL D 0.17 6.00 6.00 IIDAVIDSON C B 0.28 6.00 6.00 DAVIDSON CL B 0.24 6.00 6.00 DAVIDSON CL B 0.28 6.00 6.00 DAVIDSON CL B 0.37 6.00 6.00 II ST-CL B 0.20 6.00 6.00 DAWHOO VARIANT FSL 0.17 DECATUR CL B 0.32 6.00 6.00 DEKALB CB-FSL C 0.17 6.00 6.00 DEKALB CB-L C 0.17 6.00 6.00 DEKALB CB-SL C 0.17 6.00 6.00 DEKALB CN-FSL C 0.17 6.00 6.00 CN-L C 0.17 6.00 6.00 DEKALB DEKALB CN-SL C 0.17 6.00 6.00 DEKALB FSL C 0.24 6.00 6.00 DEKALB RB-FSL C 0.17 6.00 6.00 VI - 58 1992 TABLE 5-2 VALUES OF RUNOFF COEFFICIENT (C) FOR RATIONAL FORMULA ' Land Use C Land Use C Business: Lawns: Downtown areas 0.70-0.95 Sandy soil, flat, 2% 0.05-0.10 Neighborhood areas 0.50-0.70 Sandy soil, average, 2-7% 0.10-0.15 Sandy soil, steep, 7% 0.15-0.20 Heavy soil, flat, 2% 0.13-0.17 • Heavy soil, average, 2-7% 0.18-0.22 Heavy soil, steep, 7% 025-0.35 OW o.3, Residential: Agricultural land: Single-family areas 0.30-0.50 Bare packed soil I • Multi units, detached 0.40-0.60 * Smooth 0.30-0.60 Multi units, attached 0.60-0.75 * Rough 0.20-0.50 Suburban 0.25-0.40 Cultivated rows * Heavy soil, no crop 0.30-0.60 * Heavy soil, with crop 0.20-0.50 * Sandy soil, no crop 0.20-0.40 * Sandy soil, with crop 0.10-0.25 Pasture * Heavy soil 0.15-0.45 * Sandy soil 0.05-0.25 Woodlands 0.05-0.25 III Industrial: Streets: Light areas 0.50-0.80 Asphaltic 0.70-0.95 `fie Heavy areas 0.60-0.90 Concrete 0.80-0.95 0'-i° Brick 0.70-0.85 Parks, cemeteries 0.10-0.25 Unimproved areas 0.10-0.30 Playgrounds 0.20-0.35 Drives and walks 0.75-0.85 Railroad yard areas 0.20-0.40 Roofs 0.75-0.95 Note: The designer must use judgement to select the appropriate "Cu value within the range. Generally, larger areas with permeable soils, flat slopes and dense vegetation should have the lowest C values. Smaller areas with dense soils, moderate to steep slopes, and sparse vegetation should be assigned the highest C values. Source: American Society of Civil Engineers I V - 29 Data Server Page 1 of 4 I Precipitation Frequency D a Se b I NOAA Atlas 14,Volume 2,Version 3 ' Location name:Charlottesville,Virginia,USA' ," 1t Latitude:38.0253°,Longitude:-78.6538' F Hatt I 1 Elevation:662.27 ft*` iVi « *source:ESRI Maps f "source' POINT PRECIPITATION FREQUENCY ESTIMATES G.M.8onnin,D Martin,8 Lin,T Parzybok,M Yekta,and D Riley I NOAA,National Weather Service.Silver Spring,Maryland PF tabular I PF graphical I Maps & aerials PF tabular ' PDS-based point precipitation frequency estimates with 90%confidence intervals(in inchesthour)1 Average recurrence interval(years) 1 I Duration( 1 I 2 4. 5 II 10 ( 25 50 100 1 200 _ 500 I 1000 5-min 4.12 4.92 - 5.80 =e 7.37 8.02 8.63 9.20 9.90 I 10.6 (3.72.4.5711 (4.45.5.45) (5.23.6.41) -,i ,� - `- (6.60-8.11) (7.15-8.83) (7.64-9.52) (8.09.10.2) (8.60.11.0) (9.00-11.7) 10-min 3.29 3.94 4.64 6.22 6.87 6.38 6.86 7.30 7.83 8.24 (2.98-3.65) (3.56-4.36) (4.19-5.13) (4.70-5.76) (5.26-6.47) I (5.69-7.03) (6.08-7 56) (6.41-8.06) (6.80.8.69) (7.09-9.19) I 15-min 2.74 3.30 3.92 4.96 5.39 5.78 6.14 6.67 6.90 (2.48-3.04) I(2.89.3.65) (3.54-4.32) Fri •i I (4.45-5.46) (4,80-5.94) (5.12-6.37) (5.40-6.78) (5.71-7.29) (5.93.7.69) 30-min 1.88 2.28 2.78 3.19 3.67 4.06 4.42 4.78 6.23 6.69 (1.70-2.08) (2.06-2.52) (2.51.3.07) (2.87-3.52) (3.29-4.05) (3.62-4.47) (3.92-4.88)I (4.20.5-28) (4.54-5.80) (4.80-6.23) 60-min 1.17 1.43 1.78 2.08 2.45 2.75 3.05 3.36 3.76 - 4.08 I(1.06-1.30) (1.29-1.58) (1.61-1.97) (1.87-2.29) (2.19-2.70) (2.45-3.03) (2.70-3.36) (2.95-3.70) (3.26.4,16) (3.51-4.55) 2-hr 0.700 0.852 1.07 1.26 1.50 1.70 1.91 2.12 2.67 (0.622-0.792)(0.756-0,961) (0.948-1.20) (1.12-1.41) (1.32-1.68) (1.49-1.91) (1.66-2.14) (1.83.2.38) +6 (2.25.3.02) 0.511 0.621 0.778 0.914 1.09 1.24 1.39 1.55 1.77 1.96 I 3-hr (0.454-0.582)(0.549-0.705)(0.687-0.884) (0.805.1.04) (0.956-1.23) (1.08-1.40) (1.21-1.58) (1.33-1,76) (t50-2.02) (1.64-2.24) 0.331 0.401 0.498 0.5870.705 0.809 0.918 1.04 1.20 1.35 6-hr (0.296-0.374)(0.357-0.452)(0.442-0.561) (0.518-0.660)I(0.619.0.793)(0.704-0.908) (0.791-1.03) (0,882.1.17) (1.01-1.36) (1.12.1.53) 12-hr 0.209 0.252 0,315 0.372 0.453 0.625 0.603 0.689 0.817 0.932 (0.186-0.238)(0.224-0.288)(0.278-0.358)(0.328-0.423)(0.396.0.514)(0.453-0.595)(0.514-0.684)(0.579.0.782)(0.671-0.931) (0.753-1.07) 24-hr 0.127 0.154 0.196 0.231 0.284 0.329 0.378 0.433 0.514 0.583 (0.114-0.142)(0.138-0.172)(0.176-0.219)(0.207-0.258)(0.252.0.316)(0.289-0.365)(0.330-0.420)(0.374.0,479)(0.436.0.570)(0.488-0.647) Mb 2-day 0.075 0.091 0.115 0.135 0.164 0.188 0.215 0.243 0.285 0.320 (0.067.0.083)(0.081-0.101)(0.103-0.128)(0.121-0.151)(0.146-0.183)(0.166-0.209)(0.188-0.239)(0.211-0.271)(0.244-0.318)(0.271.0.358) 3-day 0.063 0.064 0.082 0.096 0.116 0.133 0.162 0.172 0.201 0.225 (0.048-0.059)(0.058-0.071)(0.074-0.090)(0.086-0.106)(0,104-0.128)(0.119-0.147)(0.134-0.168)(0.151-0.190)(0.174.0.223)(0.193-0.251) No 4-day 0.042 0.061 0.066 0.076 0.092 0.106 0.120 0.136 0,159 0.178 (0.039.0,047)(0.047.0,0(0.059-0.072)(0.089.0.084)(0.083.0.101)(0.095.0.116)(0.107-0.132)(0.120.0.150)+(0.139-0.175)(0.154-0.197) T-day 0.028 0.034 0.042 0.049 0.059 0.067 0.076 0.085 0.098 0.109 ,)(0.026-0.0311(0.031-0.037)(0.039-0.046)(0.045.0.053)(0.053-0.064)(0.060-0.073)(0.068.0.083)(0.075-0.093)(0.086-0.108)(0.095-0.120) 110-day (0. 0.022 0.027 0.033 0.038 0.046 0.051 0.067 0.063 0.072 0.079 am020.0.024)(0.025.0.029)0.030-0.036)(0.035-0.041)(0.041-0.049)(0.046-0.055)(0.051-0.061)(0.057.0.068)(0.064-0.078)(0.070-0.086) LO-day 0.016 0.017 0.021 0.024 0.028 0.031 0.034 0.037 0.041 0.044 _(0.014-0.016)(0.016-0.019)(0.020-0.023)(0.022-0.026)(0,028.0.030)(0.028.0.033)(0.031-0.036)(0.034.0,040)(0.037.0.044)(0.040-0.0481 1 0.012 0.014 0.017 0.019 0.021 0.023 0.025 0.027 0.029 0.031 C0-day)(0,011-0.013)10.013-0.015)(0.016-0.018)(0.017-0.020)(0.020-0.023)(0.022.0.025)'(0.023.0.027)(0.025.0.029)(0.027.0.031)(0.029.0.033) no 45-day 0.010 0.012 0.014 0.015 0.017 0.018 0.020 0.021 0.023 0.024 - (0.009.0.011))(0.011.0.012)(0.013-0.015)(0.014.0.016))(0.016-0.018)(0.017-0.020)(0.018-0.021)(0.020-0.022)(0.02i-0.024)(0.022-0.026)1 60-day 0.009 0.010 0.012 0.013 0.014 0.016 0.017 0.018 0,019 0.020 (0.006.0.009) 0.010-0.011)I(0.011-0.013)(0.012-0.1114)(0.014.0,015))(0.015-0.016)(0.016-0.018)(0.016-0,019)(0.018.0.020)(0.018-0.021) i r Precipitation frequency(PE)estimates in this table are based on frequency analysis of partial duration series(PDS). Numbers in parenthesis ere PF estimates at lower and upper bounds of the 90%confidence interval.The probability that precipitation frequency estimates (for a given duration and average recurrence interval)will be greater then the upper bound(or less than the lower bound)is 5%.Estimates at upper bounds are not checked against probable maximum precipitation(PMP)estimates and may be higher than currently valid PMP values. Please refer to NOAH Atlas 14 document for more information. a Back to Top ito is mo, http://hdsc.nws.noaa.gov/hdsc/pfds/pfdsJ3rintpage.html?lat=38.0253&lon=-78.6538&dat... 11/21/2016 .t. o • m 0 I > a N 3 47.0 CD a) a) a) a) l m N E = >, L L _C _c -9 -9 p 7 V- C C C C CIS O O CO 2 2 2 2 0 0 r` O N CO 0 N C C� C C O W ,- N CO a) a n z m 0 — Co co N CO CO C) X V N- N 0) CO O CO CO CO _ r N-CV N- n N- r z' CN (0 CO (0 f0 f0 ,0- 0. 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Client Project Job No. r Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108.01 Subject By Date Trench Drains NTJ 1/20/2017 Checked Date Sheet 1 of 1 Purpose: Determine Peak Flow for a 10 yr storm for Typical Trench Drain. r Given: Largest drainage area contributing to a trench drain: 111 Total Area,A: 3454.893 sq.ft. 0.08 acre Assumptions: Rainfall Intensity(Use a 5 min duration),i: 6.53 in/hr Runoff Coefficent(impervious runoff),C: 0.901 Calculations: Peak Flow Qp=C*i*A 0.47 cfs Conclusions: Peak flow to a trench drain will have a peak flow of 0.47 cfs. Using an ACOUSA FlowDrain FG200 with a 6"outlet can be designed for flows of 0.77 cfs. Use ACOUSA FlowDrain FG200 or simular. r r r r r r Is Is Is Is 1111 APPENDIX I Is Drop Inlets Is SIP Is Is Is Is SCS ENGINEERS Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108.01 Subject By Date Drop Inlets NTJ/DCC 7/14/2017 Checked Date AST 7/14/2017 Purpose: Size the Drop inlet A3 to protect from overtopping the berm around Sand Filter A. Given: Height of Berm at Sand Filter A: 2 ft Rim elevation above Sand Filter Surface,= 0.55 ft Assumptions: 1.Peak Flow from Drainage Area A(see Drainage Area A calculations)= 9 cfs 2.Use Performance Curve DI-1 in a Sump,From Appendix 9C-13 of the VDOT Drainage Manual. 3.Intalling multiple drop inlets at the same elevation will divide flow evenly. Calculations: Two Drop inlets Used,Qd= Qd=Q10/2 4.5 cfs See calcualtions on Appendix 9C-13. Depth of water 0.65 ft Rim Elevation+Depth of water= 1.2 Conclusions: Two drop inlets are required to keep the depth of water to 0.65ft. With the rim set 0.55 ft above filter bed surface and depth of water being 0.65 ft above the rim,the water elevation will be 0.8 ft bellow top of berm. I I I '4 r. SCS ENGINEERS Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216106.01 Subject By Date lee Storm Drains NTJ 3/3/2017 Checked Date Ow Purpose: Calculate the peak discharge for Drainage Area A fora 10 year event Given: 1.Use 10 year storm for design. 2,Areas Taken from autocad Drawings SW2. Assumptions: 1.Use NOAA Atlas 14 for intensity. 2.TR55 used to find time of concentration. 4.Cf value From VDOT Drainage Manual= 5.C values taken from page V-29 Table 5-2 of the VESCH. Calculations: 0111 Cumulative"C" C=((A1"C1)+(A2"C2)+,.,+(An+Cn))/(A1+A2+....+An) Peak Flow Q10=C"i"A"Cf Area A=A1+A2+...+An Contributing Drainage Area Area(ac) Assmued C Value Impervious Area 0.56 0.90 Pervious Area 2.50 0.35 a Intensity-assume 5 min duration. 6.53 in/hr Total Area: =lmpervous+pervious 3.06 acres Ytr Cumulative"C" C=((A1"C1)+(A2"C2)+...+(An+Cn))/(A1+A2+....+An) 0.45 tt� Peak Discharge,010: Q10=Cf"ASW1"C"i 9.0 cfs Conclusion: MO The peak flow for drainage area A is 9.0 cfs. Use this peak flow for calculating structure sizes. a ■ai 1�1 a 11U a ir Precipitation Frequency Data Server Page 1 of 4 NOAA Atlas 14,Volume 2,Version 3 0 Location name:Charlottesville,Virginia,USA* • Latitude:38.0253°,Longitude:-78.6538° Elevation:662.27 ft** •source:ESRI Maps "source:USGS POINT PRECIPITATION FREQUENCY ESTIMATES G,M.Bonin,0,Martin.B.Lin,T.Parzybok,M.Yekta,and 0.Riley NOAH,National Weather Service,Silver Spring.Maryland PF tabular I pF araDhical I Mans & aerials PF tabular I PDS-based point precipitation frequency estimates with 90%confidence intervals(in inches/hour)' 1 Average recurrence interval(years) Duration 1 2 5 10 I 25 1_10_11_2181_11 200 1 500 I 1000 4.12 4.92 6.80 1' 6.63 7.37 6.02 8.63 9.20 9.90 10.6 5-min (3.72-4.57) .(4.45-5.45) (5.23-6.41) (5.88.7.21) (6.60-8.11) (7.15-8.83) 1 (7.64-9.52) (8.09-10.2) (8.60.11,0) (9.00-11.7) 3.29 44 • 3.94 4.64 . 5.87 6.38 6.86 7.30 7.83 8.24 10-min (2.98-3.65) (3.66.4.36) (4.19-5.13) (4.70-5.76) (5.26-6.47) (5.69.7.03) , (6.08-7.56) (6.41-8.06) (6.80-8.69) ((7.09-9.19) 15-min 2.74 3.30 3.92 4.40 4.96 5.39 5.78 6,14 6.67 6.90 (2.48-3.04) (2.99-3.65) (3.64-4.32) (3.97.4.86) (4.45.5.46)I (4.80-5.94) (5.12-6.37) (5.40-6.78)I (5.71-7.29) (5.93-7.69) 30-min 1.88 2.28 2.78 3.19 3.67 4.06 I 4.42 4.78 5.23 5.69 (1.70-2.08) (2.06.2.52) (2.51-3.07) (2.87-3.52) (3.29.4,05) (3.624.47) (3.92-4.68) (4.20-5.28) (4.54.5.50) (4.80-6,23) 60-min 1.17 1.43 1.78 2.08 2.45 2.75 3.06 3.35 3.75 4.08 (1.06-1.30) (1.29.1.58) (1.61-1.97) (1.87-2.29) 1 (2.19-2.70) (2.45.3.03) (2.70.3.36) (2.95-3.70)I (3.26.4.16) I(3.514.55) 2-hr 0.700 0.862 1.07 1.26 1.50 1.70 1.91 2.12 2.42 2.67 (0.622.0.792)(0.756.0.961) (0.948-1.20) (1,12-1.41) (1.32-1.68) (1.49.1.91) (1.66-2.14) (1,83-2.38) (2.06-2.73) (2.25-3.02) 0.611 0.621 0.778 0.914 1.09 1.24 1.39 1.55 1.77 1.96 3-hr (0.454.0.582)(0.549-0.705)(0.687-0.884) (0.805.1.04) (0.956-1.23) (1.08.1.40) (1.21-1.58) (1.33-1.78) (1.50.2.02) ((1.64.2.24) 1 6-hr 0.331 0.401 0.498 0.687 0.706 0.809 - 0.918 1.04 1.20 1.35 (0.296.0.374)1{0.357.0.452(1(0.442-0.561)(0.518-0.860)0619.0.793)(0.7040.908) (0.791-103) (0.882.1.17)' (1:01.1.36) (1.12-1.53) 12-hr 0.209 0.252 0.315 0.372 0.463 0.526 0.603 0.689 0.897 0.932 (0.188.0.238}1(0.224-0.288)(0.278-0.358)1(0.328-0.423)(0.396-0.514(1(0.453-0.5>5) .514-0.684 0.579.0.782)(0.671.0.931 (0.753.1.07) 24-hr 0.127 0.154 0.196 0.231 0.284 0.329 0.378 0.433 0.514 0.683 (0.114-0.142)(0.138-0.172)(0.176-0.219)(0.207-0.258)(0.252-0.316 (0.289.0.365)4(0.330.0.420 0.374.0.479)(0.436-0.570 0.4880.647) T 2-day 0.075 0.091 0.116 0.135 0.164 0.188 0.215 0.243 0.285 0.320 (0.067.0.083)(0.081.0.101)(0.103-0.128)(0.121-0.151)(0.146-0.183) 0.166-0.209)1(0.188.0.239)(0.211-0,271)5(0.244-0.318)(0.271-0.358), 0:063 0.064 0.082 0.096 0.116 0.133 0.152 0.172 0.201 0.225 (0.048.0.059)(0.058-0.071)1(0.074-0.090)(0.086-0.106)(0.104-0-128)(0.119-0.147)1(0.134-0.168)(0.151-0.190)(0.174-0.223)(0.193-0.251)1 3-day 4-day 0.042 0.061 0.066 0.076 0.092 0.108 0.120 0.136 0.169 0.178 (0.039-0.047)(0.047-0.056)(0.059-0.072)(0.069-0.084)(0.083-0.101) (0,095-0.116)'(0.107-0.132)(0.120-0.150)(0.139-0.175)1(0.154-0.197)1 0.034 0.042 0.049 .069 0.028 0.027 0.033 0.038 OD 045 .0 051 0.057 0 063 0 072 0.07920) 87 0.076 0.085 98 (0.026-0.031)(0.031-0.037)(05.039-0.046) 0.045-0.053)(0.053-0.064) 00600 073)(0.068-0.083) 0.075-0.093)(0086 -00.108) 0.095 .1 7-day 10-day 0.022 (0.0200.0.024)(0.025-0.029)(0.030.0.096) 0.035-0.041)(0.041-0.049)1 0.046.0.055 (0.051-0.061) 0.057-0.068)(0.0640.078)(0.0700.088). 20-day 0.015 0.017 0.021 0.024 0.028 0.031 0.034 0.037 0.041 0.044 (0.014.0.016)(0.016.0.019)(0020.0.623)(0.022-0.026)11(0.026.0.030(0.028-0.033)(0,031-0.036)(0,034-0.040)(0.037-0.044)(0.040-0.048) 0.012 0.014 0.017 0.019 0.021 0.023 0.025 0.027 0.029 0:031 30-day (0.011-0.013)(0.013.0.015)(0.016-0,018((0.017.0020).(0.020-0.023)(0.022.0.0254(0.023-0.027)(0.025-0.029)(0.027-0.031)(0.029.0033) 45-day 0.010 0.012 0.014 0.016 0.017 0.018 0.020 0.021 0.023 0.024 (0.009-0.011)(0.011.0.012)(0,013.0.015)(0.0140.018).(0.016-0.018)(0.017.0.020)1(0.018-0.021)(0.020.0.022)(0.021.0.024)(0.022-0.026) 60-day 0.009 0.010 0.012 0.013 0.014 0.016 0.017 0.018 0.019 0.020 (0.008-0.009)(0.010-0.011) (0.011-0.013)1(0.012-0.014)(0.014-0.015)(0.015-0,016)(0.016.0.018)(0.016.0.019)(0.018.0.020)(0.018-0.021) 'Precipitation frequency(PF)estimates in this table are based on frequency analysis of partial duration series(PDS). Numbers in parenthesis are PF estimates at lower and upper bounds of the 90%confidence interval.The probability that precipitation frequency estimates (for a given duration and average recurrence interval)will be greeter than the upper bound(or less than the lower bound)Is 5%.Estimates at upper bounds are not checked against probable maximum precipitation(PMP)estimates and may be higher than currently valid PMP values. Please refer to NOM Atlas 14 document for more information. Back to Top http://hdsc.nws.noxa-gov/hdsc/pfds/pfds_printpage.html?Iat=3 8.0253&lon=-78.653 8&dot... 11/21/2016 6.4—Design Concepts The Rational Method Formula is expressed as follows: Q=CfCiA (6.4) Where: Q = Maximum rate of runoff, cubic feet per second (cfs) Cf = Saturation factor C = Runoff coefficient representing a ratio of runoff to rainfall (dimensionless) i = Average rainfall intensity for a duration equal to the time of concentration for a selected return period, inches per hour (in/hr) A = Drainage area contributing to the point of study, acres (ac) Note that conversion to consistent units is not required as 1 acre-inch per hour approximately equals 1 cubic foot/second. 6.4.4.1.5 Infrequent Storm The coefficients given in Appendix 6E-1 are for storms with less than a 10-year recurrence interval. Less frequent, higher intensity storms will require modification of the coefficient because infiltration and other losses have a proportionally smaller effect on runoff (Wright-McLaughlin 1969). The adjustment of the Rational Method for use with larger storms can be made by multiplying the right side of the Rational Formula by a saturation factor, C . The product of Cf and C should not111111. 1.0. Table 6-2 lists the saturation factors for the Rational Method. Table 6-2. Saturation Factors For Rational Formula Recurrence Interval (Years) Cf 2, 5, and 10 1.0 25 1.1 50 1.2 100 1.25 Note: Cf multiplied by C should not 1.0 6.4.4.1.6 Time of Concentration The time of concentration is the time required for water to flow from the hydraulically most remote point in the drainage area to the point of study. Use of the rational formula requires the time of concentration (ta) for each design point within the drainage basin. The duration of rainfall is then set equal to the time of concentration and is used to estimate the design average rainfall intensity (i) by using the B, D, & E factors in the procedure described in Appendix 6C-1. A table showing the B, D, & E factors for Virginia counties and larger cities is presented in Appendix 6C-2. Rev 4/10 Chapter 6—Hydrology VDOT Drainage Manual 6-16 of 57 I 1992 I TABLE 5-2 VALUES OF RUNOFF COEFFICIENT (C) FOR RATIONAL FORMULA I Land Use C Land Use C Business: Lawns: Downtown areas 0.70-0.95 Sandy soil, flat, 2% 0.05-0.10 Neighborhood areas 0.50-0.70 Sandy soil, average, 2-7% 0.10-0.15 Sandy soil, steep, 7% 0.15-0.20 Heavy soil,flat, 2% 0.13-0.17 Heavy soil, average, 2-7% 0.18-0.22 R y soil,steep,7% t3:"25.0 VS6 03. Residential: Agricultural land: I Single-family areas 0.30-0.50 Bare packed soil Multi units, detached 0.40-0.60 * Smooth 0.30-0.60 Multi units, attached 0.60-0.75 * Rough 0.20-0.50 I Suburban 0.25-0.40 Cultivated rows * Heavy soil, no crop 0.30-0.60 * Heavy soil,with crop 0.20-0.50 * Sandy soil, no crop 0.20-0.40 I* Sandy soil, with crop 0.10-0.25 Pasture * Heavy soil 0.15-0.45 * Sandy soil 0.05-0.25 I Woodlands 0.05-0.25 Industrial: Streets: I Light areas 050-0.80 Asphaltic r` , " ' '-'6 Heavy areas 0.60-0.90 Concrete 0.80-0.95 0'4® Brick 0.70-0.85 - Parks, cemeteries 0.10-0.25 Unimproved areas 0.10-0.30 1 Playgrounds 0.20-0.35 Drives and walks 0.75-0.85 Railroad yard areas 0.20-0.40 Roofs 0.75-0.95 I Not@: The designer must use judgement to select the appropriate "C" value within the I range. Generally, larger areas with permeable soils, flat slopes and dense vegetation should have the lowest C values. Smaller areas with dense soils, moderate to steep slopes, and sparse vegetation should be assigned the highest C values. I Source: American Society of Civil Engineers I V - 29 I Chapter 9— Storm Drains Appendix 9C-13 Performance Curve DI-1 in a Sump cY4_ S-74.vCvc AAE A3 Q. DES\LIN = 1'I►S L�rS i Dol- e, 1— I— l w .o 111 • r { OPEN AREA = 2.33 FT2 PERIMETER = 9.00 FT 1 in tkSc4S DI Si_HA E ( CFS ) 1 -010 YN L-FTs v Seb flews q 1V t)Et) arwieeN Z-N-'twt , Source: VDOT Transportation Research Council publication "HYDRAULIC EFFICIENCY OF GRATE INLET", 1988 1 of 1 VDOT Drainage Manual SCS ENGINEERS Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108.01 Subject By Date Drop Inlets NTJ/DCC 7/14/2017 Checked Date AST 7/14/2017 Purpose: Size the Drop inlet A4 to protect from overtopping the berm. Given: Height of Berm at Sand Filter B: 4 ft Rim Elevation(From Sand Filter Rim Elevations) 0.5 ft • Assumptions: 1.Peak flow from Drainage Area B(see Drainage Area B Calculations)= 5.2 cfs 1.Assume a design flow of: 6.0 cfs 2.Use Performance Curve DI-1 in a Sump From Appendix 9C-13 of the VDOT Drainage Manual. 4.Assume 50%o clogged. Calculations: ' See calcualtions on Appendix 9C-13. Depth of water 1.1 ft Water Surface height=Depth of Water+Rim Elevation 1.6 ' Conclusions: One drop inlet is required to keep the depth of water to 1.6 ft which is less than the Sand Filter berm. I 1 I I Chapter 9–Storm Drains Appendix 9C-13 Performance Curve 01-1 in a Sump �0 Z s't-(tV CTV P A c( iso _ QDeSiUN 6.o (CS — j r r _- - r — As _.— _ /f Tt q% � --r I--LL w i 5 rj r• OPEN AREA = 2.33 FT2 PERIMETER = 9.00 FT D I }C H r'=a R O E ( CP; Source: VDOT Transportation Research Council publication "HYDRAULIC EFFICIENCY OF GRATE INLET", 1988 1 of 1 VDOT Drainage Manual SCS ENGINEERS Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108.01 Subject By Date Drop Inlets NTJ/DCC 7/14/2017 Checked Date AST 7/14/2017 Purpose: Size the Drop Inlet A7 yard drain to prevent overtopping into the tunnel access road. ' Given: Height to roadway surrounding yard inlet= 0.75 ft 1 Assumptions: 1.Peak Flow from Drainage Area C(drainage area smaller)= 1.2 cfs 2.Assume a design flow of= 2.0 cfs 3.Use Performance Curve DI-1 in a Sump,From Appendix 9C-13 of the VDOT Drainage Manual. 4.Assume 50%clogging: Calculations: ' See calcualtions on Appendix 9C-13. Depth of water 0.25 ft Conclusions: The water will pool to 0.25 feet above the rim of the drop inlet and not run into the roadway for a 10 year storm event. , 1 I I Chapter 9— Storm Drains Appendix 9C-13 Performance Curve DI-1 in a Sump S—crtl.U0161E A (s. l 6,") 2 c95. I 0 11111 / 1/11111111111111111 IM■ ■ ■■II / 11111111K1111111111111•111111111■��■U■IIM�M �■■ ■ I o — IIHWAS • 1.111111.1111111111.11.1151111111..11111- ■■■11t� � 11.11111110 II / Mill II ^r` IL 11111 d11117 ��111I■1 MUM CJ "MEM EN 1=111.11.111111111110111 Pi, . 111 ran 1111111111111111.11 .111.111111111. .. om! uII Rulni NJ . - i ynhI 1 1 111 OPEN AREA = 2.33 FT2 '" PERIMETER = 9.00 FT • 0_ I I I Fi I ei t ci I i'j(f ti CS DI'�C.HARC E ( CFS ) I Source: VDOT Transportation Research Council publication "HYDRAULIC IEFFICIENCY OF GRATE INLET", 1988 I 1 of 1 VDOT Drainage Manual I SCS ENGINEERS Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108.01 Subject By Date Drop Inlets NTJ/DCC 7/14/2017 Checked Date AST 7/14/2017 Purpose: Size the Drop inlet A9 to protect from overtopping the berm of Sand Filter C. Given: Height of Berm at Sand Filter C: 2 ft Rim Elevation above Sand Filter Surface= 0.5 ft , Assumptions: 1.Peak Flow from Drainage Area C= 1.2 cfs 2.Assume a design flow of: 2.0 cfs 3.Use Performance Curver DI-1 in a Sump From Appendix 9C-13 of the VDOT Drainage Manual. 4.Assume 50%Clogging. Calculations: See calcualtions on Appendix 9C-13. Depth of water 0.25 ft Water Surface Height=Rim Elevation+Depth of Water 0.75 Conclusions: The Water Surface Height is 0.75 ft and will not overtop the Sand Filters Perimeter Berm. ' Ii 1 I s r r a SCS ENGINEERS Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108.01 Subject By Date + Storm Drains NTJ 3/3/2017 Checked Date - Purpose: Calculate the peak discharge for Drainage Area C for a 10 year event Given: 1.Use 10 year storm for design. 2.Areas Taken from autocad Drawings SW2. Assumptions: 1.Use NOAA Atlas 14 for intensity 2.Assume a Time of Concentration of 5 min 4.Cf value From VDOT Drainage Manual= 1 5.C values taken from page V-29 Table 5-2 of the VESCH Calculations: M Cumulative"C" C=((A1"C1)+(A2"C2)+,,,+(An+Cn))/(A1+A2+....+An) Peak Flow Q10=C"i"A"Cf Area A=A1+A2+.. +An Contributing Drainage Area Area(ac) Assmued C Value Impervious Area 0.13 0.90 Pervious Area 0.17 0.35 r, Intensity-5 min duration. 6 53 in/hr Total Area: =lmpervous+pervious 0 30 acres Cumulative"C' I C ((A1"C1)+(A2"C2)+.._+(An+Cn))/(A1+A2+ ,+An) 0,59 ge,Q10: Q10=Cf A*C"i 1 2 cfs Conclusion: The peak flow for drainage area c is 1.2 cfs and need a minimum pipe diameter of 6 inches to support peak discharge, NIB I I Precipitation Frequency Data Server Page 1 of 4 I NOAA Atlas 14,Volume 2,Version 3 • \ Location name:Charlottesville,Virginia,USA* - ! Latitude:38.0253°,Longitude:-78.6538° :. [ ili , Elevation:662.27 ft** I 'source.ESRI Maps source:USGS POINT PRECIPITATION FREQUENCY ESTIMATES I G M.Bonnin,0 Martin,B.Lin,T.Parzybok,M Yekta,and 0 Riley NOAA,National Weather Service.Silver Spring,Maryland PF tabular I PF graphical I Mans & aerials PF tabular I PDS-based point precipitation frequency estimates with 90% confidence intervals(in incheslhour)1 I Average recurrence interval(years) I Duration1 ( 2 j__..5_ j 10 j 25 j so 100 200 500 1000 5-min 4.12 4.92 5.80 6.63 7.37 8.02 8.63 9.20 9.90 10.5 (3.72.4.57) (4.45-5.45) (5.23-6.41) (5.88-7.21) (6.60-8.11) (7.15-8.83) (7.64-9.52) (8,09-10.2)ii (8.60-11.0) I(9,00-11 7) 10-min 3.29 3.94 4.64 5.87 6.38 6.86 7.30 7.83 8.24 (2.98-3.65) (3.56.4.36) (4.19-5.13) (4.70-5.76) (5.26-6.47) (5.69-7.03) (6.08-7.56) (6.41-8,06) (6.80-8.69) (7.09-9.19) ,' 15-min 2.74 3.30 3.92 4.40 4.96 5.39 5.78 6.14 6.57 6.90 (2.48-3.04) (2.99.3.65) (3.54-4.32) (3.97.4.86) (4.45.5.46) (4.80-5.94) (5-12-6.37) I (5.40.6.78) (5.71-7.29) [(55993.7.69) 30-min 1.88 2.28 2.78 3.19 3.67 4.06 4.42 4.78 6.23 6.59 (1,70.2.08) (2.06-2.52) (2.51-3.07) (2.87.3.52) (3.29.4.05) (3.62.4.47) (3.92.4.88) (4.20-5.28) (4,54-5.80) (4,80.6,23) 60-min 1.17 1.43 1.78 2.08 2.46 2.75 3.06 3.35 3.76 4.08 I(1.06-1.30) (1.29-1.58) (1.61-1.97) (1.87-2.29) (2.19-2.70) (2.45-3.03) (2.70-3.36) (2.95.3.70) (3.29.4.16) (3.51-4.55) 2-hr 0.700 0.852 1.07 1.26 1.50 1.70 1.91 2.12 2.42 2.67 1(0.6224.792)(0.756-0.961) (0.948-1.20) (1.12-1.41) (1.32-1.68) (1.49-1.91)_ (1.66-2.14) (1.83-2.38) (2.06-2.73) (2.25.3.02) 3-hr 0.511 0.621 0.778 0.914 1.09 1.24 1.39 1.55 1.77 1.96 I(0.454-0.582)(0.549-0.705)(0.687-0.884) (0.805.1.04) (0.956-1.23) (1.08-1.40) (1.21-1.58) (1,33-1.76) (1.50-2.02) (1.64.2.24) 6-hr 0.331 0.401 0.498 0.587 0.705 0.809 0.918 1.04 1.20 1.35 (0.296.0.374)(0.357-0.452)(0.442.0.561)(0.518.0.660)(0.619-0.793)(0.704.0.908).(0.791-1.03) (0.882-1.17) (1.01-1.36) (1.12-1.53) 12-hr 0.209 0.252 0.316 0.372 0.453 0.526 0.603 0.689 0.817 0.932 (0.186-0.238)(0.224.0.288)(0.278-0.358)(0.328-0.423)(0.396-0.514)(0.453-0.595)(0.514-0.684)(0.579-0.782)(0.671-0 931) (0.753-1.07) I24-hr 0.127 0.154 0.196 0.231 0.284 0.329 0.378 0.433 0.614 0.683 I(0.114-0.142)(0.138-0.172)(0.176-0.219)(0.207.0.258)((0.252.0.316)(0.289.0.365)(0.330.0.420)(0374-0.479)(0.436-0.570)(0.488.0.647) 2-day 0.075 0.091 ) 0.115 0.136 0.164 0.188 0.216 0.243 0.285 0.320 1( y )(0.067-0.083)j(0.081-0.101 (0.103-0.128)(0.121-0.151)(0.146-0.183(0.166.0.209)(0.188.0.239)(0.211-0.271)(0.244-0.318)(0.271-0.358) I 3-day 0:063 0.064 0.082 0.096 0.116 0.133 0.162 0.172 0.201 0.225 {0.048-0.059)(0.058.0.071)(0.074.0.090)(0.086.0.106)(0.104-0.128(0.119.0.147)(0.134-0.168)( 1 0.151-0.190)(0.1740.223)(0.193-0.251) I. 4-day 0.042 0.051 0.065 0.076 0.092 0.106 0.120 0.136 0.159 0.178 (0.039-0.047)1(0.047.0.056)(0.059-0.072)(0.069.0.084)(0.083-0.101)(0.095-0.116)(0.107-0.132)(0.120-0.150)(0.139-0.175)(0.154.0.197) 7-day 0.028 0.034 0.042 0.049 0.069 0.067 0.076 0.086 0.098 0.109 I(0.026.0.031)(0.031.0.037)(0.039-0.0461(0.045.0.053)(0.053.0.064)(0.060.0.073)(0.068.0.083)(0.075-0.093)(0.086-0.108)(0.095-0.120) 10-day 0.022 0.027 0.033 0.038 0.045 0.061 0.057 0.063 0.072 0.079 (0.020-0.024)(0.025-0.029)(0.030.0.036)(0.035-0.041) (0.041-0,049)(0.046.0.055)4(0.051-0.061)(0.057.0.068)(0.064-0.078)(0.070-0.086) 20-day 0.015 0.017 0.021 0.024 0.028 0.031 0.034 0.037 0.041 0.044 (0.014.0.016)40.016.0.019)(0.020-0.023)(0.022.0.026)(0.026-0.030)(0,028-0.033)(0.031-0.036)(0.034-0.040)(0.037-0.044)(0.040-0.048) 30-day 0.012 0.014 0.017 0.019 0.021 0.023 0.025 0.027 0.029 0.031I (0.011.0.013)(0.013.0.015)(0.016-0.018)(0.017.0.020)(0,020.0.023)(0.022-0.025)(0.0234.027)(0.025-0.029)(0.027-0.031)(0.029-0.033) 45-day 0.0100.012 0.014 0.015 0.017 0.018 0.020 0.021 0.023 0.024 (0.009-0,011)(0.011-0.012)(0.013-0.015)(0.014-0.0161(0.016.0.018)(0.017-0.020)(0.018-0.021)(0.020-0.022)(0.021-0.024)(0.022-0.026) - 60-day 0.009 0.010 0.012 0.013 0.014 0.016 0.017 0.018 0.019 0.020 I (0.008.0.009)(0.010.0.011)(0.011.0.013)(0.012-0.014) (0.014-0.015)(0.015-0.016)(0.016-0.018)(0.016-0.019)(0.018-0.020) (0.018-0.021) Precipitation frequency(PF)estimates in this table are based on frequency analysis of partial duration series(PDS). Numbers In parenthesis are PF estimates at lower and upper bounds of the 90%confidence interval.The probability that precipitation frequency estimates (for a given duration and average recurrence interval)will be greater than the upper bound(or less than the lower bound)is 5%.Estimates at upper bounds I are not checked against probable maximum precipitation(PMP)estimates and may be higher than currently valid PMP values. _Please refer to NOAA Atlas 14 document for more information. Sack to TOD i me i http://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.htm I?lat=3 8.0253&ton=-78.653 8&dat... 11/21/2016 i 6.4—Design Concepts The Rational Method Formula is expressed as follows: Q=CfCiA (6.4) Where: Q = Maximum rate of runoff, cubic feet per second (cfs) Cf = Saturation factor C = Runoff coefficient representing a ratio of runoff to rainfall (dimensionless) i = Average rainfall intensity for a duration equal to the time of concentration for a selected return period, inches per hour(in/hr) A = Drainage area contributing to the point of study, acres (ac) Note that conversion to consistent units is not required as 1 acre-inch per hour approximately equals 1 cubic foot/second. 6.44.1.5 Infrequent Storm The coefficients given in Appendix 6E-1 are for storms with less than a 10-year recurrence interval. Less frequent, higher intensity storms will require modification of the coefficient because infiltration and other losses have a proportionally smaller effect on runoff(Wright-McLaughlin 1969). The adjustment of the Rational Method for use with larger storms can be made by multiplying the right side of the Rational Formula by a saturation factor, Cf. The product of Cf and C should not 1.0. Table 6-2 lists the saturation factors for the Rational Method. Table 6-2. Saturation Factors For Rational Formula Recurrence Interval (Years) Cf 2, 5, and 10 1.0 25 1.1 50 1.2 100 1.25 Note: Cf multiplied by C should not 1.0 64.4.1.6 Time of Concentration The time of concentration is the time required for water to flow from the hydraulically most remote point in the drainage area to the point of study. Use of the rational formula requires the time of concentration (tc) for each design point within the drainage basin. The duration of rainfall is then set equal to the time of concentration and is used to estimate the design average rainfall intensity (i) by using the B, D, & E factors in the procedure described in Appendix 6C-1. A table showing the B, D, & E factors for Virginia counties and larger cities is presented in Appendix 6C-2. * Rev 4/10 Chapter 6—Hydrology VDOT Drainage Manual 6-16 of 57 I 1992 I TABLE 5-2 I VALUES OF RUNOFF COEFFICIENT (C) FOR RATIONAL FORMULA 1 Land Use C Land Use C - I Business: Lawns: Downtown areas 0.70-0.95 Sandy soil, flat, 2% 0.05-0.10 I Neighborhood areas 0.50-0.70 Sandy soil, average, 2-7% 0.10-0.15 Sandy soil, steep, 7% 0.15-0.20 Heavy soil, flat, 2% 0.13-0.17 Heavy soil, average, 2-7% 0.18-0.22 I Heavy soil, steep, 7% 0.25-0.35 JSP 0 3' Residential: Agricultural land: Single-family areas 0.30-0.50 Bare packed soil Multi units, detached 0.40-0.60 * Smooth 0.30-0.60 Multi units, attached 0.60-0.75 * Rough 0.20-0.50 Suburban 0.25-0.40 Cultivated rows I* Heavy soil, no crop 0.30-0.60 * Heavy soil, with crop 0.20-0.50 * Sandy soil, no crop 0.20-0.40 I* Sandy soil, with crop 0.10-0.25 Pasture * Heavy soil 0.15-0.45 * Sandy soil 0.05-0.25 I Woodlands 0.05-0.25 Industrial: Streets: Light areas 0.50-0.80 Asphaltic , £ - ' 0.70-0.95 `r'`' I Heavy areas 0.60-0.90 Concrete 0.80-0.95 '.1 � ° Brick 0.70-0.85 Parks, cemeteries 0.10-0.25 Unimproved areas 0.10-0.30 I Playgrounds 0.20-0.35 Drives and walks 0.75-0.85 Railroad yard areas 0.20-0.40 Roofs 0.75-0.95 I Note: The designer must use judgement to select the appropriate "C" value within the range. Generally, larger areas with permeable soils, flat slopes and dense I vegetation should have the lowest C values. Smaller areas with dense soils, moderate to steep slopes, and sparse vegetation should be assigned the highest C values. or Source: American Society of Civil Engineers la al V - 29 in Chapter 9— Storm Drains Appendix 9C-13 Performance Curve DI-1 in a Sump �Dt2 S�'(ZULTV RE f� I a D., t,„.) = 2 c �S J 0 . I;t / i f I f r - i r J . � L' . 5 /f i L OPEN AREA = 2.33 FT2 PERIMETER = 9.00 FT I . i � 10 11,)0 C!I CHAR C,F t is F Source: VDOT Transportation Research Council publication "HYDRAULIC EFFICIENCY OF GRATE INLET", 1988 1 of 1 VDOT Drainage Manual 1 SCS ENGINEERS ' Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108.01 Subject By Date Drop Inlets NTJ/DCC 7/14/2017 Checked Date AST 7/14/2017 Purpose: Size the Drop Inlet All yard drain to prevent overtopping into surrounding access road. i Given: Height to roadway surrounding yard inlet= 2 ft Assumptions: 1.Peak Flow from Drainage Area C(drainage area smaller)= 1.2 cfs 2.Assume a design flow of= 2.0 cfs 3.Use Performance Curve DI-1 in a Sump,From Appendix 9C-13 of the VDOT Drainage Manual. 4.Assume 50%clogging: Calculations: See calcualtions on Appendix 9C-13. Depth of water 0.25 ft Conclusions: The water will pool to 0.25 feet above the rim of the drop inlet and not run into the roadway for a 10 year storm event. ' 1 1 I r Chapter 9—Storm Drains Appendix 9C-13 Performance Curve 01-1 in a Sump S1'ZuCrvftC— A11 Q �FS�c�H1 Z � �S .1 " �- 1 1- 1 . 0LL - u i I a \-)i 0 �1 OPEN AREA = 2.33 FT2 PERIMETER = 9.00 FT 171 Z C•S DISCHAR[ E :) Source: VDOT Transportation Research Council publication "HYDRAULIC EFFICIENCY OF GRATE INLET", 1988 1 of 1 VDOT Drainage Manual SCS ENGINEERS ' Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108.01 Subject By Date Drop Inlets NTJ/DCC 7/14/2017 Checked Date AST 7/14/2017 Purpose: Size the Drop inlet Al2 to protect from overtopping the Sand Filter D Berm. Given: Height of Berm at Sand Filter D: 2 ft Rim Elevation of drop Inlet above filter bed(See Sand Filter D Calculations)= 0.5 ft Assumptions: 1.Peak Flow from Drainage Area D= 1.2 cfs 2.Assume a design flow of= 2.0 cfs 3.Use Performance Curver DI-1 in a Sump From Appendix 9C-13 of the VDOT Drainage Manual. 4.Intalling multiple drop inlets at the same elevation will divide flow evenly. Calculations: See calcualtions on Appendix 9C-13. Depth of water 0.25 ft Water Surface Height=Rim Elevation+Depth of Water 0.75 Conclusions: The water surface height is 0.75 ft and will not overtop the Sand Filter D perimeter berm. I t SCS ENGINEERS i Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108.01 Subject By Date +. Storm Drains NTJ 3/3/2017 Checked Date ▪ Purpose: Calculate the peak discharge for Drainage Area D for a 10 year event Given: 1 Use 10 year storm for design. 2 Areas Taken from autocad Drawings SW2 kiss Assumptions: 1 Use NOAA Atlas 14 for intensity. 2 Assume a Time of Concentration of 5 min 4.Cf value From VDOT Drainage Manual= 1 5 C values taken from page V-29 Table 5-2 of the VESCH. Calculations: ▪ Cumulative"C" C=((A1*C1)+(A2*C2)+...+(An+Cn))/(A1+A2+_..+An) Peak Flow Q10=C*i*A*Cf Area A=A1+A2+. +An Contributing Drainage Area Area(ac) Assmued C Value Impervious Area 0.17 0.90 Pervious Area 0.08 0 35 Intensity-assume 5 min duration 6 53 in/hr Total Area: =lmpervous+Pervious 0.25 acres ✓ Cumulative"C' C=((A1'C1)+(A2'C2)+.._+(An+Cn))/(A1+A2+... +An) 0.72 Peak Discharge,Q10: Q10=Cf A`C1 1 2 cfs Conclusion: The peak flow for drainage area D is 1 2 cfs. OM r I Chapter 9—Storm Drains I Appendix 9C-13 Performance Curve DI-1 in a Sump I ST 2v c-N-v2 C- A I`2._. I C4 Es i c, A) 2 c 4)5 / / / / I r' r'-! i / �J r' L=1 _ . / . 0. F / / OPEN AREA = 2.33 FT2 I C PERIMETER = 9.00 FT I 140 L50 Ili)01 Z C,- .S DIS[THPRGE ( CFS ) I I Source: VDOT Transportation Research Council publication"HYDRAULIC EFFICIENCY OF GRATE INLET", 1988 I I I of 1 VDOT Drainage Manual SCS ENGINEERS Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108.01 Subject By Date Drop Inlets NTJ/DCC 7/14/2017 Checked Date AST 7/14/2017 Purpose: Size the Drop Inlet A16 to protect overtoping into the north access road. Given: Height of roadway above rim elevation= 2 ft ar Assumptions: 1.Peak Flow from A16= 2.8 cfs 2.Assume a design flow of= 3.0 cfs r 3.Use Performance Curve DI-1 in a Sump,From Appendix 9C-13 of the VDOT Drainage Manual. 4.Assume 50%clogging: Calculations: See calcualtions on Appendix 9C-13. Depth of water 0.35 ft Conclusions: The water will pool to 0.35 feet above the rim of the drop inlet and not run into the roadway for a 10 year storm event. Oil MIN 1111111 NIB SCS ENGINEERS ' Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108.01 Subject By Date Storm Drains NTJ 3/3/2017 Checked Date Purpose: Calculate the peak discharge for drainage area contributing to structure Al6 on the the landfill cap for a 10 year event Given: 1 Use 10 year storm for design. 2 Areas Taken from autocad Drawings SW2 Assumptions: 1 Use NOAA Atlas 14 for intensity 2 Assume a Time of Concentration of 5 min. 4 Cf value From VDOT Drainage Manual= 1 5.C values taken from page V-29 Table 5-2 of the VESCH. Calculations: Cumulative"C' C=((A1*C1)+(A2*C2)+_,+(An+Cn))/(A1+A2+. .+-An) Peak Flow Q10=C*i*A*Cf Area A=A1+A2+,.+An Contributing Drainage Area Area(ac) Assmued C Value Impervious Area 0 09 0.90 Pervious Area 1.00 0 35 Time of Concentration,TC= 5.00 min Intensity-assume 5 min duration 6.53 in/hr Total Area: =Impervous+Pervious 1.09 acres Cumulative"C" C=((A1'C1)+(A2'C2)+,. +(An+Cn))/(A1+A2+.. .+An) 040 Peak Discharge,Q10: 010=Cf'ASW1'C'1 2.8 cfs Conclusion: The peak flow for drainage area to structure A16 is 2.8 cfs use a design of 3.0 cfs. 1 . i `If � II .. II ��Ii ��'i ��f err �i ■�rl �� fl1 • -H m Y ` ' Z > 1 k. 1 cMZO 0 III 1 x l ti l► \I Illill x i z v/ 3j ti U)1 i. D (� 0 fes -rl ' ) I • W = D Cr x ..0 ,r I Z V x t A ` .0 CD ' \ 1 1 (0 ''.,, D Ifi G7 `` I 0 0 1, fle '4 1 \ 1(7141 • ---- 1) 1 .; - Ie ' - - - _ - -- "- I -- y fF l`J -�� 4� x1 "� (,) , f ni : rD f- nm TI . mom Ar � pG� D mi , Q0 I- � o (,, . . D, �� AZO D3i 1 I ii , ,--- I.- �11 �, I I:.:- n I _ ,,1..) I a ii ,. O y j '''. --)* ' mZ 1 MDi la _73. 1 hii___„ ,„ rw.% w II iii° , , ,- „,,,, D ► � _ r � -- ,,,,,,, - _ _ _ _ \ , )I,, - cr,-- \ ......,_ _ _ ,.. i-' Irz, r- 1 ... : 1 _...„ I1 prA>16.7 L:: .. . .. _.i,” 1 \ ,-,-, 0 - \ ___ \N ---!,-.,.......-:\ - 7,--0. , ,„.., ,,,,--: 1---JF----4>,.---- _ r, ` ,,,. r1 0 _ __ .„\ ,..A, . . , 0 , . ) ..,... \ , , , ___ _ _ ____ _ _ _ _ _ _ _ __ ____ i _ , , '.. \ _ , , › _ r,-, _ _ _ - 0 --_ oa, 0x___, m - "�\�\--, .4. - - -` umillN m0 71Z \ e _.-c, Ni.. ...„....s,, , ,, ,+ p (i) > -1-12 ° ,-,..,..„. ci., , , ___ _ _ _ AIM Precipitation Frequency Data Server Page 1 of 4 AEI NOAA Atlas 14,Volume 2,Version 3 ' Location name:Charlottesville,Virginia,USA* t ,. -, Latitude:38.0253°,Longitude:-78.6538` ., Elevation:662.27 ft" woi AN . .' -source'ESRI Maps f "source:USGS POINT PRECIPITATION FREQUENCY ESTIMATES G.M Bonnin,0 Martin,B On,T Parzybok,M.Yekta,and U Riley .. NOAA,National Weather Service,Silver Spring,Maryland PF tabular i PF graphical(Maps & aerials ..... PF tabular PDS-based point precipitation frequency estimates with 90% confidence intervals(in inches/hour)1 Average recurrence interval(years) _3 Duration 1 J1 2 I 5 11 10 r 25-11-- --11-710-in 200 500 1000 (-m5-mtn 4.12 4.92 6.80 7.37 8.02 8.63 9.20 9.90 10.5 (372.4.57) (4.45-5.45)]((5.23.6.41) (z' Ij (6.60-8.11) ((7.15-8.83) (7.64-9.52) (8.09-10.2) (8.60-11.0) (9.00-11 7) 10-min 3.29 3.94 4.64 5.22 5.87 6.38 6.86 7.30 7.83 8.24 (2 98-3.65) (3.56.4.361 (4.19-5.13) (4 70-5 76) (5.26-6.47) (5.69-7.03) (6.08-7.56) (6.41-8.06) (6.80-8.69), (7.09-9.(9) me 2,74 3.30 3.92 4.40 (I 4.96 5.39 5.78 6.14 6.57 6.90 15-min] (2.48-3.04)l (2.99.3.65) (3.54-4.32) (3.97.4.86) ]l(4.45-5.46) (4.80.5.94)(5.12-6.37) (5.40-6.78) (5.71-7.29) (5.93.7.69) 30-min 11 1.88 2.28 2.78 3.19 3.67 4.06 4.42 4.78 6.23 5.59 (1 70-2.08) (2.06.2.52) (2.51-3.07) (2.87.3.52) (3.29.4.05) (3.62.4.47) (3.92488)] (4.20.5-28) (4.54.5.80) (4.80-6.23) 60-min 1.17 1.43 1.78 2.08 2.45 2.75 3.06 3.35 3.75 4.08 .M I (1.06-1.30) (1.29-1.58) (1.61-1.97) (1.87-2.29)l (2.19-2.70) (2.45-3.03) (2.70.3.36) (2.95-3.70) (3.26-4.16) (3.51-4.55) L2-hr 0.700 0.852 1.07 1.26 1.50 1.70 1.91 2.12 2.42 2.67 _.- (0.622-0.792) (0.756-0.9611 (0.948.1.20) (1.12-1.411 (1.32-1.68) (1.49-1.91) (1.66-2.14) (1.83-2.38) (2.06.2.73 (2.25-3.02) 3-hr 0.611 0.621 0.778 0.914 1.09 1.24 1.39 1.55 1.77 1.96 (0.454-0.582)(0.549-0.705)(0.687-0.884) (0.805.1.04) (0.956.1.23)] (1.08-140) (1.21.1.58) (1.33-1.76) (1.50-2.02) (1.64.2.24) 6-hr 0.331 0.401 0.498 0.587 0.706 0.809 0.918 1.04 1.20 1.35 (0.296.0.374) (0.357-0.452)(0.442.0.561)(0.518-0.660)(0.619-0.793)(0.704-0.908) (0.791-1-03) (0.882-1.17) (1.01-1.36) (1.12-1.53) ( 0.209 0.262 0.315 0.372 0.453 0.526 0.603 0.689 0.817 0.932 I 12-hr (0.186.0.238)(0.224-0.288)0.2780.358)(0.328-0.423)(0.396-0.514)(0.453.0.595)(0.514.0.684)(0.579-0.782)'(0.671.0,931) (0.753-1.07) lI 0.127 0.154 0.196 0.231 0.284 0.329 0.378 0.433 0.514 0.683 24-hr 11(0.114-0.142)(0.138-0 172)10.176-0.219)1(0.207.0.258)10.252.0.316) (0.289.0.365) .330-0.420)(0.374-0.479)-(0.436-0.510)(0.488-0.647), 0 075 0 091 43 0 285 0 20 2-day 1(0.06.7-0.083)I((0.061-0 101)l(0.103-05 28))0 12110.151)(0.146-0.4183)(0.166.0 209)(0.18.8-0.239 (0.211-0 271)(0.244.U 318)(0.271-0 358)} I 3-day 0:053 0.064 0.0820.096 0.116 0.133 0.152 0.172 0.201 0.225 (0.048.0.059)(0.058-0.071)(0.074.0.09) 0.086-0.106)(0.104-0.128)(0.119-0.147) (0.134-0.168)(0.151-0.190)(0.174.0.223)(0.193-0.251) 4-da 0.042 0.061 0.066 0.076 0.092 0.106 0.120 D.1 0.159 0.178 y 10.039-0.047)(0.047-0.056)(0.059.0.072)[(0.069-0.084)(0.083-0.101)(0.095.0.116)( 360.107-0.132)(0.120-0.150)(0.139-0.175)(0.154-0.197) 7-day 0.028 -0.034 0.042 0.049 0.059 0.067 0.076 0.085 I 0.098 0.109 (0.026-0.031)(0.031.0.037)(0.039-0.046)(0.045.0.053)(0.053-0.064)(0.060.0.073)(0.068-0.083)1{0.075.0.093)1(0086.0.108)(0.095.0.120) 10-day 0.022 0.027 0.033 0.038 0.046 0.061 0.057 0.063 0.072 0.079 (0.020-0.024)(0.025.0.029)(0.030-0.036)(0.035.0.041)(0041-0.049)40.046.0.055)(0.051-0.061)(0.057.0.068)(0.064.0.078)(0070.0.086), 20-day1 0.016 0.017 0.021 0.024 0.028 0.031 0.034 0.037 0.041 0.044 T (0.014-0.016)(0.016-0.019)(0.020-0.023)(0.022.0.026)(0.026-0.030)(0.028.0.033)(0.031-0.036)(0.034-0.040)(0.037-0.044)(0.040-0,048) 30-day 0.012 0.014 0.017 0.019 0.021 0.023 0.026 0.027 0.029 0.031 Alli 10.011-0.013)(0.013-0.015)(0.016.0.018)(0.017-0.020) (0.020.0.023)10.022-0.025)(0.023-0.027)40.025.0.029)(0.027-0.031)(0.029.0.033)] 45-day 0.010 0.012 0.014 0.015 0.017 0.018 0.020 0.021 0.023 0.024 (0.009-0.011)(0.011-0.012)((0.013-0.015)(0.014.0.0161(0.016.0.018)(0.017.0.020)(0.018-0.021) (0.020-0.022)(0.021.0.024)(0.022.0.026) 60-day 0.009 0.010 0.012 j 0.013 0.014 I 0.016 0 017 0.016 0.019 0.020 I (0.008.0.009) (0.01D-0.011)(0.011-0.013)I(0.U12-0.014)(0.014.0.0151110.015-0.016)((0.016-0.018)(0.016-0.019)(0.018-0.020)(0.018.0.02t) MN Precipitation frequency(PF)estimates in this table are based on frequency analysis of partial duration series(PDS). Numbers in parenthesis are PF estimates at lower and upper bounds of the 90%confidence interval.The probability that precipitation frequency estimates (for a given duration and average recurrence interval)will be greater than the upper bound(or less than the lower bound)is 5%.Estimates at upper bounds are not checked against probable maximum precipitation(PMP)estimates and may be higher than currently valid PMP values Please refer to NOAA Atlas 14 document for more information. Back to Top II i i http://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.htm l?1at=3 8.0253&ton=-78.6538&dat... 11/21/2016 1 F 1992 1 TABLE 5-2 VALUES OF RUNOFF COEFFICIENT (C) FOR RATIONAL FORMULA Land Use C Land Use C Business: Lawns: Downtown areas 0.70-0.95 Sandy soil, flat, 2% 0.05-0.10 Neighborhood areas 0.50-0.70 Sandy soil, average, 2-7% 0.10-0.15 Sandy soil, steep, 7% 0.15-0.20 Heavy soil, flat, 2% 0.13-0.17 Heavy soil, average, 2-7% 0.18-0.22 Heavy soil, steep, 7% 0.25-0.35 OSS o. ' Residential: Agricultural land: Single-family areas 0.30-0.50 Bare packed soil Multi units, detached 0.40-0.60 * Smooth 0.30-0.60 Multi units, attached 0.60-0.75 * Rough 0.20-0.50 Suburban 0.25-0.40 Cultivated rows * Heavy soil, no crop 0.30-0.60 ■r * Heavy soil, with crop 0.20-0.50 * Sandy soil, no crop 0.20-0.40 * Sandy soil, with crop 0.10-0.25 Pasture ea * Heavy soil 0.15-0.45 * Sandy soil 0.05-0.25 Woodlands 0.05-0.25 Industrial: Streets: Light areas 0.50-0.80 Asphaltic 0.70-0.95 `SE Heavy areas 0.60-0.90 Concrete 0.80-0.95 �� rn Brick 0.70-0.85 Parks, cemeteries 0.10-0.25 Unimproved areas 0.10-0.30 Playgrounds 0.20-0.35 Drives and walks 0.75-0.85 Railroad yard areas 0.20-0.40 Roofs 0.75-0.95 Note: The designer must use judgement to select the appropriate "C" value within the range. Generally, larger areas with permeable soils, flat slopes and dense vegetation should have the lowest C values. Smaller areas with dense soils, moderate to steep slopes, and sparse vegetation should be assigned the highest C values. r Source: American Society of Civil Engineers ea V - 29 Chapter 9— Storm Drains Appendix 9C-13 Performance Curve DI-1 in a Sump Alb ' ?0'� . 'i7r✓S (pit/ �� GP:s 1 0 . 1%t - / . ei Z ! r' - L sr IJ OPEN AREA = 2.33 FT2 PERIMETER = 9.00 FT 0. 1 ^ j 1 0 50 1I:)0 UG yJ DISCHARGE i CFS U I Source: VDOT Transportation Research Council publication "HYDRAULIC EFFICIENCY OF GRATE INLET", 1988 Ii 1 of 1 VDOT Drainage Manual 1 I 1 1 APPENDIX J ' Outlet Protection ' SCS ENGINEERS Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108.01 Subject By Date Storm Drain Outlet Protection NTJ/DCC 7/14/2017 Checked AST 7/14/2017 Purpose: Determine adequate outlet protection into to the Stormwater Basin for a 10 year event. Given: 1.Use 10 year storm for design. 2.Outlet Pipe Size= 24 inches Assumptions: 1. Use the Peak Dishcarge From Structure Al Fomr the Storm Sewers Extension, 0= 14.4 cfs 2.Assume Minimum Tailwater Condition. Calculations: Using Plate 3.18-3 From VESCH d50= 0.5 ft Width= 14 ft Conclusion: The peak flow for the project area is 14.4 cfs and need a minimum pipe diameter of 24 inches to support peak discharge. Class Al Standard VDOT riprap will be needed for the outlet protection for a minimum distance of 14 feet. For design,the riprap will extend to the permanent pool elevation. 11111 1r IMO i 15 in co CO — Cs1 > 0 cv Lr) — r-- 0 I CO ce; r; 4 ca to iti CO up -4. 0 cp N g. cc I ID c, ce 0. i.r.-4 tg o 1 8 > I On 8 0 .......... (.0 ..,- cz. I • to 8 CI e-- . . %. . --) c ...., . ..] ..:.1 I . a) a ,0 z cg . . Es ., . a r 8 A.. _ t.... . .., ., . 3 .. . ..,-- 0 ....... co (.0 . c. "... .. 1g cs.-x C•1 4 VPI CL .. 01 1-0: r--. v- Cl) 6. 1 •...-, ‘- •MOP . .I; . *I. g 0 I I 2 u_ ..... 2.. ..cLI Q. D •,....- ,-- . to ..:, cp t-,.. . t-- . c , 0 t: MB c) qt.-. . LI, i-- Ct. \ C (0 a 0 ca zr. . co (D MI , > 0 owww. . C) c, -C a) 0 O. tv > 8.... . imml .. 0 v- CD . 0 0 111111 (7 'V 0 15 0 8 8 8 8 8 8 iii L r<I to g us CIto 6 - P to' i: N. 0N- tfl ti a) CD C a) a. c ....1 :-.1 _ le IN 1992 3.18 OM ‘1n — 1.aa4 'azis de.AdLU OSp --V — � i./. II inn1Ci1tia s Z� 6 �_C=C_Cr mask.-3 , i - /94 � 6 € == =ems -t - - �`.O; l4� _ .'=_ "—gym ..'�- i�`:m�'aa, .. - • - __�_ fn • s �__ . ___ Rte_ _ /9 � _ i -- ME 116...A.-1 ---f--,-*loir+.74:.: ....&---Lf-SE=7.=5-....--- -t I MI �'� 0TH►=L . w w 'ai-ifi.�iiG =MUM Y� _�:� w - 3 �• - . = , dam::. 1 ..9 :UM"` ia. Bk: Pio.:`,oza:a�" o l�Y� '7ifiiiifiiOf f■�'� lo N -.Q it 7 Mff Cfwf*\y iii KS ___,_. \ Nf - c-/0 .. .. tSi1[!fEi }a MIIMI sa l { . . A ..__ GS MN —_ -nfaa flea- 4a,— fursoiss mos r R � r 0 ......s 4-7 11.0115111411 I•••- C� SSMill= _L= _ `S v- INN 1u Eftn-_! ii�w��,iiii�=mss_�v ..O _c f. oH�a - .1 -i �...A,_.�A t J 'gco ot Mg i ;i=fi:!Viii 0 A r w two m- s-Mni� _ �L¢� j-_ �n ��O Cl) y ii .a .ayyuw lir �In ■fiC� L -� N J W W▪ W s✓ -i/fO■II��allainli 0 y ■ffrfff ■■■■ 1'1i1■ p ■f„.___.` ` fa- 9 \ 4 ' •� rj e G�• b -- (, vi Go .. .L0 ci ‘,,,i -e ._-=am iii t.Riff___. ,l 1 Li 11111 g , 1111111 i illi f i La C3 N J --- _---T=_. ..N .- �• Wiriiiii Mile J Q M p I 1-3 {$ E M I o-. -, 01 N i tll t • Z? E G co f i-f G,- .{ '._ ..' O 0. z 0505 e �o ,%\ o e I Source: USDA-SCS Plate 3.18-3 III - 164 I Chapter 7—Ditches and Channels ` ' - I Appendix 7D-3 Standard VDOT Riprap Classifications, I Weights, and Blanket Thickness Classification DS0 (ft) W50 (lbs) T (in) I Class Al 0.8 50 20 Class I 1.1 100 26 Class II 1.6 300 38 I Class III 2.2 1000 53 Type I 2.8 2000 60 I Type II 4.5 8000 r 97 II I . I I I I . b, 1 of 1 VDOT Drainage Manual . SCS ENGINEERS Client Project Job No. Rivanna Solid Waste Authority New Ivy Solid Waste Transfer Station 02216108.01 Subject By Date Trench Drain Gravel Diaphragm Outlet Protection DCC 7/14/2017 Checked Date AST 7/14/2017 Purpose: Determine adequate outlet protection for the trench drains. Given: 1.Use 10 year storm for design. 2.Outlet Pipe Size= 6 inches 3.Drainage area used as surrogate for all drainage areas going to trench drains: 0.08 acres 4.Trench drain has slope of 1.0%slope. 5.Mannings(in trench drain pipe),n: 0.013 Assumptions: 1. Use 5-Minute time of concentration. 2.Rainfall Intensity(NOAA Atlas 14 for Charlottesville,VA),is 6.53 in/hour 3.Runoff Coefficient(Table 5-2 for"Asphalt Streets"),C: 0.9 NMI Calculations: Rational Method Qpeak=CiA Qpeak= 0.5 cfs Vpeak= 3.2 fps Conclusion: The peak flow for the surrogate area to the trench drain is 0.5 cfs.At the peak,a velocity of 3.2 fps is obtained. Based on the peak velocity,VDOT#78,#8,or#8P pea gravel shall be used for outlet protection as Mil NMI 40 i i SCS ENGINEERS Client Project Job No. Rivanna Solid Waste Authority New Solid Waste Transfer Station 02216108.01 Subject By Date Exising Zero Discharge Sediment basin discharge DCC 7/14/2017 Checked Date Sheet 1 of 1 Purpose: Determine the existing sediment basin discharge during a 1,2,10,25,100 year storm event. Given: Existing water elevation= 693.6 ft From Topograph dated 7/7/99. Emergency Spill way elevation= 697.9 ft From Joyce Engineering dated 1998 Drainage Area= 11.03 acres From Drawing G2. n. Assumptions: 1.Existing water elevation acts as drainage basin bottom. 2.Contours taken from drawing G2 Property Information 1. 3.Distribution Type II SIN 4.Shape Factor 484 5.24 hour storm duration. Calculations: Composite curve number= 77 From Hydrograph No.1 Rivanna Stormwater Basin-Inflow Time of Concentration= 18.3 min From Hydrograph No.1 Rivanna Stormwatei Water Elevation for 1 year strom= 694.06 ft Water Elevation for 2 year strom= 694.26 ft Water Elevation for 10 year strom= 694.85 ft Water Elevation for 25 year strom= 695.43 ft Water Elevation for 100 year strom= 696.08 ft Conclusions: The existing stormwater basin will not discharge during a 24 hour 1,2,10,25,or 100 year storm event. 1 1 1 1 in _ 1 0 O C .. N T O) O T T O a ON N T -- N co F°-W m O N CNI OO 3 Eo` N d Cr) M U m COCO r (d c o m w ( 1 !Q 0 0o.a�0 oN''�`NcwL a m ° S' ma o °ao 0 T -17 G O L I frau = S 1 r C III 4 Y s O J I• (n H Z i CNM N co 03 i C/) in CC C CO 1116 Ce a , c • Cal• 1 O j a) Oft Z x o 0 0 O O Oo O OD U tly N +� _ I 1 1 I I I i 1 I L._�—1 I I 1 1 1 I i I 1 I I 1 I (n o 0 .2 .. a. i�. Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v10.5 Monday,03/13 1 2017 Hyd. No. 2 Stormwater Basin-Inflo Hydrograph type = Reservoir Peak discharge = 0.000 cfs Storm frequency = 100 yrs Time to peak = n/a Time interval = 1 min Hyd. volume = 0 cuft Inflow hyd. No. = 1 - Rivanna Stormwater Basin evElevation = 696.08 ft Reservoir name = Rivanna Sed Basin Max. Storage = 247,960 cuft Storage Indication method used. rrr Stormwater Basin-Inflo Elev(ft) Hyd. No.2--100 Year Elev(ft) 698.00 698.00 697.00 697.00 r�r 696.00 696.00 rrr , 695.00 695.00 694.00 694.00 .ri 693.00 693.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time(hrs) 1. Rivanna Sed Basin .rr I Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v10.5 Monday,03/13/2017 Hyd. No. 2 I Stormwater Basin-Inflo Hydrograph type = Reservoir Peak discharge = 0.000 cfs Storm frequency = 10 yrs Time to peak = n/a Time interval = 1 min Hyd. volume = 0 cuft Inflow hyd. No. = 1 - Rivanna Stormwater Basin-lolly Elevation = 694.85 ft Reservoir name = Rivanna Sed Basin Max. Storage = 122,288 cuft Storage Indication method used. I Stormwater Basin-Inflo Elev ftElev(ft) ( ) Hyd. No.2--10 Year 696.00 — 696.00 I 695.00 - - - 695.00 a 694.00 694.00 I .0001 693.00 693.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time(hrs) 1.Rivanna Sed Basin I Itir Hydrograph Reportif Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2018 by Autodesk,Inc.v10.5 Monday,03/13/2017 Hyd. No. 2 rr Stormwater Basin-Inflo Hydrograph type = Reservoir Peak discharge = 0.000 cfs +� Storm frequency = 2 yrs Time to peak = n/a Time interval = 1 min Hyd. volume = 0 cuft Inflow hyd. No. = 1 - Rivanna Stormwater Basin-kifinviElevation = 694.26 ft Reservoir name = Rivanna Sed Basin Max. Storage = 62,272 cuft Storage Indication method used. r rr Stormwater Basin-Inflo Elev(ft) Hyd. No. 2--2 Year Elev(ft) 696.00 - 696.00 +rr 695.00 695.00 rr 694.00 694.00 rr rr 693.00 693.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time(hrs) ,r 1. Rivanna Sed Basin rr Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v11 Thursday,07/6/2017 Hyd. No. 2 Stormwater Basin-Inflo Hydrograph type = Reservoir Peak discharge = 0.000 cfs Storm frequency = 1 yrs Time to peak = n/a Time interval = 1 min Hyd. volume = 0 cuft Inflow hyd. No. = 1 - Rivanna Stormwater BasinovElevation = 694.06 ft Reservoir name = Rivanna Sed Basin Max. Storage = 42,396 cuft I Storage Indication method used. I I Stormwater Basin-Inflo I Elev(ft) Hyd. No. 2-- 1 Year Elev(ft) 696.00 696.00 I I 695.00 695.00 I 1 694.00 694.00 I I 693.00 693.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time(hrs) 1. Rivanna Sed Basin rr Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v10.5 Monday,03/13/2017 Hyd. No. 1 Rivanna Stormwater Basin-Inflow Hydrograph type = SCS Runoff Peak discharge = 82.42 cfs Storm frequency = 100 yrs Time to peak = 12.07 hrs Time interval = 1 min Hyd. volume = 247,960 cuft Drainage area = 11.030 ac Curve number = 77* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 18.30 min Total precip. = 9.07 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 Composite(Area/CN)_[(1.220 x 87)+(3.060 x 78)+(6.750 x 74)]/11.030 1- Rivanna Stormwater Basin-Inflow Q(cfs) Hyd. No. 1 —100 Year Q(cfs) 90.00 90.00 rr 80.00 80.00 70.00 70.00 �.' 60.00 60.00 50.00 50.00 40.00 40.00 30.00 30.00 ✓r 20.00 - 20.00 ✓r 10.00 - 10.00 rri 0.00 — 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Hyd No. 1 Time(hrs) I Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v10.5 Monday,03/13/2017 Hyd. No. 1I Rivanna Stormwater Basin-Inflow Hydrograph type = SCS Runoff Peak discharge = 41.29 cfs Storm frequency = 10 yrs Time to peak = 12.07 hrs Time interval = 1 min Hyd. volume = 122,289 cuft Drainage area = 11.030 ac Curve number = 77* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 18.30 min Total precip. = 5.55 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 Composite(Area/CN)=[(1.220 x 87)+(3.060 x 78)+(6.750 x 74))/11.030 Rivanna Stormwater Basin-Inflow Q(cfs) Q(cfs) � Hyd. No. 1 --10 Year 50.00 50.00 40.00 40.00 1 I 30.00 30.00 20.00 20.00 I 10.00 10.00 0.00 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time(hrs) Hyd No. 1 I :3 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v10.5 Monday,03/13/2017 Hyd. No. 1 Rivanna Stormwater Basin-Inflow Hydrograph type = SCS Runoff Peak discharge = 20.81 cfs - Storm frequency = 2 yrs Time to peak = 12.07 hrs Time interval = 1 min Hyd. volume = 62,272 cuft Drainage area = 11.030 ac Curve number = 77* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 18.30 min Total precip. = 3.69 in Distribution = Type II ss Storm duration = 24 hrs Shape factor = 484 Composite(Area/CN)=((1.220 x 87)+(3.060 x 78)+(6.750 x 74)]/11.030 Rivanna Stormwater Basin-Inflow Q(cfs) Hyd. No. 1 --2 Year Q(cfs) 21.00 21.00 18.00 18.00 W 15.00 - 15.00 i.r 12.00 12.00 rrw 9.00 9.00 6.00 6.00 +• 3.00 3.00 r.' 0.00 41/4"".... 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 1111 Time(hrs) Hyd No. 1 r■ 1111 1 Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk,Inc.v11 Thursday,07/6/2017 Hyd. No. 1 Rivanna Stormwater Basin-Inflow Hydrograph type = SCS Runoff Peak discharge = 13.88 cfs Storm frequency = 1 yrs Time to peak = 725 min I Time interval = 1 min Hyd. volume = 42,396 cuft Drainage area = 11.030 ac Curve number = 77* Basin Slope = 0.0 % Hydraulic length = 0 ftI Tc method = TR55 Time of conc. (Tc) = 18.30 min Total precip. = 3.00 in Distribution = Type II Storm duration = 24 hrs Shape factor = 4841 *Composite(Area/CN)=[(1.220 x 87)+(3.060 x 78)+(6.750 x 74)]/11.030 Rivanna Stormwater Basin-Inflow Q (cfs) Hyd. No. 1 -- 1 Year Q(cfs) 14.00 14.00 12.00 12.00 10.00 10.00 8.00 8.00 I 6.00 6.00 I 4.00 4.00 2.00 - 2.00 0.00 - / - 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Time(min) Hyd No. 1 SEDIMENT BASIN ADEQUACY CHECK Project: New Ivy Solid Waste Transfer Station Location:Existing Zero Discharge Sediment Basin Total design area draining to basin: 11.3 acres. Basin Volume Design Wet Storage: 1.Minimum required Volume=67 cu.Yds.X Total Drainage Area(acres). i 67 cu.Yds X 11.3 acres= 757.1 cu.Yds. ow 2.Available Basin Volume= 19360.0 cu.Yds at elevation 693.6 ft. (From Joyce Engineering,INC.Water Storage Pond Drawings,dated 1998) Dry Storage: wr 3.Minimum required Volume=67 cu.Yds.X Total Drainage Area(acres). 67 cu.Yds X 11.3 acres= 757.1 cu.Yds. 4. Total available dry storage basin volume at maximum allowable water level= 11454.6 cu.Yds at elevation 696.40 ft. (From Joyce Engineering,INC.Water Storage Pond Drawings,dated 1998) Minimum=134 cu.Yds./acre of total drainage area. Required Total Storage= 1514.2 cu.Yds. Available Total Storage= 30814.6 cu.Yds. ✓w O N 1 1 1 1 1 1 1 1 1 i i 1 1 1 1 1 1 Runoff Volume and Curve Number Calculations enter design ti002 rainfall depth lin) ixe..Mona t ya.Vann 1 O y..r porn, NOW Ilsreairanol Ill ns cars rv.mur, ., .....<....a:.,,...... a..... .............. .....,........ bl.amp Vol..OM to,rate..1...vetoc....11 Oran.,wen mml.e In vwum.uvnrn le s,a.4erLne.b.Iraq Moan.. .0 Oa.rre ryuaeun Runoff mnsuM 1,hater.. irew.and sham,Inthe weasn.n as IIVIrrageoc.land cao Wy Ce cr00Ice Cm.y Orlars<Oslo,nsawn Ow ceg ace pmta<.ei000*0d!«m.arras re eaoat.OOflr x.r.: m.)rr.Ib.rnulli.Iad by[ha drarw.e we. SO tit,an ea.]..n.meedx _a..ev,e- O a e s egyx- Ire a_Im ,1m.......0.5.a,c1 OK, ar'..rvea..e Nos Drainage Area Curve Numbers and Runoff Depths. Curve number,if N.(Nud,)and runoff depict(RV,,,,,,„1 ore remputed w11O and wdveut eedvet.en procures. am nm u:10 uw I -.... w a.nNn.. Om 59 I iiiee.waw tte.r.aw.n tor•...± RVp,.,. ,(....0.4 CoN.urhrsolwa laysloa000. 1l 14 ma l •ee.., t-r.-r.rv.„iN wrM Rano*arearl im t. la —"'See Ooxe.abuw t a: ,.a. rsa,ss 1 uin14 • iea...l•rnl_.._i rr tea, I.m j . .r1.1 a w.�...0; am am Sew.pig awate.asCoact abr am 1k 00 1 —rol 11VF„*(.10.1 MlrcN.N.hm Rwren•edue.bn•{ 1 h 101 +31/,,,,,,lu.nr el..isiiti with 0u..11 a.dw Iron•, gtt 115 em adtuaeCN• I, n at .a.M. —�_`� �mW res above '�I.aa . a.nlM1 1 assn, -__-. ors1 _. C Seals e o 1 DDD ..... . Om Ga+aa++w. �+a I.r.a'�; om 00o p0.1 7 am u.w r.......rx..ala _ .: c1 a ss „„rawen..r.w 0m Am 0 C a.w --.•f oa w as v. Sh0.0 el_...I (_-t.- I t ye,'Mew aye.poem__..i> .e.a. 00,„,,,,,,feve.00 00.0ur v a0f One no. AV... ( .r wammr l h fl a.d 000 Obs _.. OW _ ad}.mdru• a a • _..,... . e Nnrcr nor,.., .—��_-. y ...... .....,s,... �- mama,.aru0 Otma ...1.00 CfaM 05... _.._„ ,.. Ca. am .0 J..m.....- -.,.acre.•:✓,,:.,. .. 0 O Dm000 }an y,g CO .s.<.. um AW MOO .g pp C'10-6211, .____}..___1 t.Le.u0ewr !,year scorn. 1r,-"plats RNp,,,..g.a fwm ...e. ortaa. N von. a.non sears tIon• Om Cpu om am Nva•,,.,.,teme..M nroOl wiehle00411.1ut1eae• 00a Dcc ...a�._. 010 adluned or I a a • -Spy No!es above I _ 1t O N M ( aM Cres *sent to o co m am am 3 o o Vie.,storm trm.t�^•_.to-v.ra ii Av.....a,.Menorw oral wino no awaff•Nsatlive nn 0m om y,.,eetwes wig wl.h•IwwaaeIadan• 000 - om _t "See Note:000w I Chapter 2 Estimating Runoff Technical Release 55 I Urban Hydrology for Small Watersheds Co a U E F0.2 -,.. 0 ,^) c A i Al d#C7 C— I p-2C"A Table 2-2d Runoff curve numbers for arid and semiarid rangelands 1/ lommemmi Curve numbers for Cover description -- hydrologic soil group I Hydrologic Cover type condition 21 A 3/ B C D Herbaceous—mixture of grass,weeds,and Poor 80 87 93 I low-growing brush,with brush the Fair 71 81 89 minor element. Good 62 'I'+* 85 Oak-aspen—mountain brush mixture of oak brush, Poor 66 74 79 I aspen,mountain mahogany,bitter brush,maple, Fair 48 57 63 and other brush. Good 30 41 48 Pinyon-juniper—pinyon,juniper,or both; Poor 75 85 89 I grass understory. Fair 58 73 80 Good 41 61 71 Sagebrush with grass understory. Poor 67 80 85 I Fair 51 63 70 Good 35 47 55 i Ili Desert shrub—major plants include saltbush, Poor 63 77 85 88 greasewood,creosotebush,blackbrush,bursage, Fair 55 72 81 86 palo verde,mesquite,and cactus. Good 49 68 79 84 Mb 1 Average runoff condition,and Ia,=0.2S.For range in humid regions,use table 2-2c. 2 Poor: <30%ground cover(litter,grass,and brush overstory). Fair: 30 to 70%ground cover. Good: >70%ground cover. NB 3 Curve numbers for group A have been developed only for desert shrub. IND Mb ilk ilia SW s 2-8 (210-VI-TR-55,Second Ed.,June 1986) TR55 Tc Worksheet Hydraflow Hydrographs Extension for AutoCAD®Civil 3D®2016 by Autodesk, Inc.v10.5 Hyd. No. 1 Rivanna Sed Basin Description A B C Totals Sheet Flow Manning's n-value = 0.240 0.011 0.011 Flow length (ft) = 150.0 0.0 0.0 Two-year 24-hr precip. (in) = 5.55 0.00 0.00 Land slope (%) = 2.00 0.00 0.00 Travel Time (min) = 14.99 + 0.00 + 0.00 = 14.99 Shallow Concentrated Flow Flow length (ft) = 150.00 0.00 0.00 Watercourse slope (%) = 8.00 0.00 0.00 Surface description = Unpaved Paved Paved Average velocity (ft/s) =4.56 0.00 0.00 Travel Time (min) = 0.55 + 0.00 + 0.00 = 0.55 Channel Flow X sectional flow area (sqft) = 1.87 2.15 0.00 Wetted perimeter (ft) = 5.00 3.74 0.00 Channel slope (%) = 5.00 1.00 0.00 Manning's n-value = 0.035 0.015 0.015 Velocity (ft/s) =4.93 6.85 0.00 Flow length (ft) ({0})520.0 400.0 0.0 Travel Time (min) = 1.76 + 0.97 + 0.00 = 2.73 Total Travel Time, Tc 18.27 min t 1 1 Chapter 3 Time of Concentration and Travel Time Technical Release 55 ' Urban Hydrology for Small Watersheds Sheet flow For sheet flow of less than 300 feet,use Manning's kinematic solution(Overtop and Meadows 1976)to Sheet flow is flow over plane surfaces.It usually compute Tt: occurs in the headwater of streams.With sheet flow, , 0.8 the friction value(Manning's n)is an effective rough- _0.007nL) ness coefficient that includes the effect of raindrop Tt (P `0.530.4 [eq.3-3] impact;drag over the plane surface;obstacles such as L) litter,crop ridges,and rocks; and erosion and trans- where: portation of sediment.These n values are for very shallow flow depths of about 0.1 foot or so.Table 3-1 Tt = travel time(hr), gives Marming's n values for sheet flow for various n = Manning's roughness coefficient(table 3-1) surface conditions. L =flow length(ft) P2 = 2-year,24-hour rainfall(in) s = slope of hydraulic grade line Table 3-1 Roughness coefficients(Manning's n)for (land slope,ft/ft) sheet flow I This simplified form of the Manning's kinematic solu- Surface description n tion is based on the following:(1)shallow steady uniform flow,(2)constant intensity of rainfall excess Smooth surfaces(concrete,asphalt, (that part of a rain available for runoff), (3)rainfall gravel,or bare soil) 0.011 duration of 24 hours,and(4)minor effect of infiltra- Fallow(no residue) 0.05 tion on travel time.Rainfall depth can be obtained Cultivated soils: from appendix B. ' Residue cover 520% 0.06 Residue cover>20% 0.17 Shallow concentrated flow Grass: Short grass prairie 0.15 After a maximum of 300 feet,sheet flow usually be- Dense grasses 2;} comes shallow concentrated flow.The average veloc- Bermudagrass. 0.41 ity for this flow can be determined from figure 3-1,in 0.13 which average velocity is a function of watercourse Range(natural) slope and type of channel.For slopes less than 0.005 Woo Light underbrush 0.40 ftlft,use equations given in appendix F for figure 3-1. Dense underbrush 0.80 Tillage can affect the direction of shallow concen- --- — trated flow.Flow may not always be directly down the I The n values are a composite of information compiled by Engman watershed slope if tillage runs across the slope. .� (1986). 2 Includes species such as weeping lovegrass,bluegrass,buffalo After determining average velocity in figure 3-1,use grass,blue grama grass,and native grass mixtures. s When selecting n,consider cover to a height of about 0.1 ft.This equation 3-1 to estimate travel time for the shallow is the only part of the plant cover that will obstruct sheet flow. concentrated flow segment. Open channels Open channels are assumed to begin where surveyed cross section information has been obtained,where channels are visible on aerial photographs,or where blue lines(indicating streams)appear on United States Geological Survey(USGS)quadrangle sheets. Manning's equation or water surface profile informa- tion can be used to estimate average flow velocity. rr Average flow velocity is usually determined for bank- full elevation. a (210-VI-TR-55,Second Ed.,June 1986) 3-3 r Channel Report c �,U�v � n°t t7 Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk,Inc. Tuesday,Jan 24 2017 Channel 1 East of Site Triangular Highlighted Side Slopes (z:1) = 3.00, 3.00 Depth (ft) = 0.79 Total Depth (ft) = 1.00 Q (cfs) = 9.000 Area (sqft) = 1.87 Invert Elev (ft) = 1.00 Velocity (ft/s) = 4.81 Slope (%) = 5.00 Wetted Perim (ft) = 5.00 N-Value = 0.035 Crit Depth, Yc (ft) = 0.90 Top Width (ft) = 4.74 Calculations EGL (ft) = 1.15 Compute by: Known Q Known Q (cfs) = 9.00 Elev (ft) Depth ft( , Section 3.00 - 2.00 2.50 - - - 1.50 2.00 1.00 1.50 - - 0.50 1.00 - --- 0.00 0.50 -0.50 0 1 2 3 4 5 6 7 8 Reach (ft) I Figure B-2 Approximate geographic boundaries for NRCS(SCS)rainfall distributions 1 I ), / --- - 1 1-----IA -1,---/' L- -¢iii j �__ 1 , HI I C ..tJ T ! y �- I 1 III 1 otik Rainfall Distribution � j ~ J:7 r, z. ` ill Type 1 1 i r. �x s t _ n Type IA ,a t, E i I I Type II I Vsb its ® Type III I III oar III 1 Rainfall data sources 1 This section lists the most current 24-hour rainfall data Commerce,National Weather Service,NOAA Atlas 2. published by the National Weather Service(NWS)for Silver Spring,MD. various parts of the country.Because NWS Technical 1 Paper 40(TP-40)is out of print,the 24-hour rainfall Alaska maps for areas east of the 105th meridian are included Miller,John F. 1963.Probable maximum precipitation here as figures B-3 through B-8.For the area generally and rainfall-frequency data for Alaska for areas to 400 west of the 105th meridian,TP-40 has been superseded square miles,durations to 24 hours and return periods by NOAA Atlas 2,the Precipitation-Frequency Atlas of from 1 to 100 years.U.S.Dept.of Commerce,Weather the Western United States,published by the National Bur.Tech. Pap. No.47.Washington,DC. 69 p. Ocean and Atmospheric Administration. Hawaii East of 105th meridian Weather Bureau. 1962.Rainfall-frequency atlas of the "r Hershfield,D.M. 1961.Rainfall frequency atlas of the Hawaiian Islands for areas to 200 square miles,dura- United States for durations from 30 minutes to 24 tions to 24 hours and return periods from 1 to 100 hours and return periods from 1 to 100 years.U.S. years.U.S. Dept.Commerce,Weather Bur.Tech.Pap. us Dept.Commerce,Weather Bur.Tech.Pap.No.40. No.43.Washington,DC.60 p. Washington,DC. 155 p. Puerto Rico and Virgin Islands West of 105th meridian Weather Bureau. 1961.Generalized estimates of prob- r Miller,J.F.,R.H. Frederick,and R.J.Tracey. 1973. able maximum precipitation and rainfall-frequency Precipitation-frequency atlas of the Western United data for Puerto Rico and Virgin Islands for areas to 400 States.Vol.I Montana;Vol.II,Wyoming;Vol III,Colo- square miles, durations to 24 hours,and return periods a rado;Vol.IV,New Mexico;Vol V,Idaho;Vol.VI,Utah; from 1 to 100 years.U.S. Dept. Commerce,Weather Vol.VII,Nevada;Vol.VIII,Arizona;Vol.IX,Washing- Bur.Tech. Pap. No.42.Washington,DC.94 P. ton;Vol.X,Oregon;Vol.XI,California.U.S.Dept.of a B-2 (210-VI-TR-55,Second Ed.,June 1986) a bill Precipitation Frequency Data Server Page 1 of 4 r NOAA Atlas 14,Volume 2,Version 3 e N. Location name:Charlottesville,Virginia,USA' r t P Latitude:38.0253°,Longitude:-78.6538° Elevation:662.27 ft" i `source:ESRI Maps •`source.USGS POINT PRECIPITATION FREQUENCY ESTIMATES G.M Bonnie,D.Martin,B.Lin.T.Parzybok,M.Yekta.and D.Riley aim NOAA,National Weather Service,Silver Spring,Maryland PF tabular I PF graphical I Maps & aerials ,. PF tabular PDS-based point precipitation frequency estimates with 90%confidence intervals(in inches)1 Durations- Average recurrence interval(years) 1 2 5 10 25 50 1 100 200 soo 1000 1 rir 0.343 0.410 0.483 0.644 0.614 0.668 0.719 0.767 0.825 0.873 5-min (0-310-0.3811(0.371-0.454)(0.436-0.534)(0.490-0.601)10.550-0.676)I(0.596.0.736)I(0.637.0.793)(0.674.0.847)1(0.717-0.915) 0.750-0.973) 10-min 0.648 0.656 0.774 0.870 0.978 1.06 1.14 1.22 1.31 1.37 (0.496.0.608)(0.594-0.727)(0.699.0.855)(0.784-0.960) (0.877-1.08) (0.949-1.17) (1,01•1.26)(1,01.1.26) (1.07-1,34) I (1.13-1.45) (1.18-1,53) 41111 15-min 0.686 0.825 0.979 1.10 1.24 1.35 1.44 1.54 1.64 1.73 (0.620-0.760)(0.747-0.913) (0.884-1.08) (0.992-1.22)1 (1.11-1.37) (1.20.1.48) (1.28.1,59) (1.35-1.70) (1.43-1.82) (1.48-1.92) 30-min 0.940 1.14 1.39 1.59 1.84 2.03 2.21 2.39 2.61 2.79 (0.849-1.04) (1.03-1.26) (1.26-1,54) (1.44-1.76) 1165-2.02) (1.81-2.24) (1.96-2.44) (2.10-2.64) (2.27-2.90) (2.40.3.11) 60-min 1.17 1.43 1.78 2.08 2.46 2.76 3.05 3.35 3.75 4.08 INN (1.06-1.30) (1.29-1.58) (1.61-1.97) (1.87-2.29) (2.19-2.70) (2,45.3.03) (2.70-3.36) (2.95-3.70) (3.26-4.16) (3.51-4.55) 2-hr 1.40 1.70 2.14 2.61 3.00 3.40 3.81 4.24 4.84 6.34 (1.25-1.59) (1.51-1.92) (1.90-2.41) (2.23-2.83) (2.64-3.37) (2.98-3.82) (3.32.4.28) (3.66-4,77) (4.12-5.45) (4 49-6 04) 3-hr 1.64 1.87 2.34 2.74 3.28 3.72 4.18 4.66 6.33 6.89 (1.36-1.75) (1.65-2.12) (2.06.2.66) (2.42-3.11) (2,87-3.71) (3.24-4.21) (3.62.4.73)J (4.00-5.28) (4.50-6.05) (4.92.6,71) 6-hr 1.99 2.40 2.98 3.61 4.22 4.86 5.50 6.20 7.21 8.10 (1.77-2.24) (2.14-2.71) (2.65-3.36) (3.10-3.96) (3.71-4.75) (4.22-5.44) (4.74-6.18) (5.28-6.98) (6.04-8.14) (6.68-9.17) 12-hr 2.62 3.04 3.79 4.49 6.46 6.33 7.27 8.31 9.84 11.2 I (2.24-2.87) (2.70.3.46) (3.35-4.32) (3.95-5.10) (4.77-6.19) (5.46-7.17) (6.19-8.24) (6.98-9.42) (8.09-11.2) (9.07-12.8) 24-hr 3.05 3.69 4.70 5.556,81 7.89 9.07 10.4 12,3 14.0 (2.74-3.41) (3.32-4.13) (4.22-5.26) (4.96-6.200 (6.04-7.59) (6.95-8.77) (7.92-10.1) (8.96-11.5) (10.5-13.7) (11.7-15.5) 3.59 4.36 6.52 6.48 7.88 9.05 10.3 11.7 13.7 16.4 2-day (3.23-4.01) (3.91.4.861 (4.96.6.16) (5.80-7.23) (7.00-8.76) (7.98-10.0) (9.02-11.5) I(10.1-13.0) (11.7-15.3) (13.0-17.2) I 3-day 3.82 4.63 5.87 6.36 9.59 10.9 12.4 (3.46-4.24) (4.19.5.14) (5.31-6.51) 6.89(6.22-7.63) I 17,50-9.25) (8.55-10.6) (9.66-12.1) (10.9-13.7)Jj( 14.6 16.2 12.5-16.0) (13.9-18.0) 4-day 4.05 4.91 6.22 7.29 8.84 10.1 11,6 13.0 16.2 17.1 (3.70-4.48) (4.48-5.41) (5.67-6.86) (6.63-8.03) (8.01-9.74) (9.12-11.2)l 110.3-12.7)I (11.6-14.4) (13.4-16.8) (14.8-18.9) I ;11.70- 7-day 6.66 7.07 8.23 9.87 112 12.7 14.2 16.5 18.3 (4,31.5.14) (5.19-6.19) (6.47-7.73) (7.51.8.99) (8.97-10.8) (10.1-12.3) l(11.4-13.9) ((12.7-15 6) (14,5.18.1) (15.9-20.2) 10-day 6.34 SAO 7.90 9.10 10.8 12.1 13.6 16.1 17.2 19.0 (4.91-5.79) (5.90.6.94) (7.27-8.551 (8.35-9.85) (9.85-11.7) (11.0-13.2) (12.3-14.77) (13.6-16.4) i (15.3-18.7 (16.7-20.7) 20-da] 7.00 1.35 10.1 11.4 13.3 14.7 16.2 17.7 19.7 21.3 �JJJJJJ (6.54.7.53) 17.80.8.97) (9.40.10.8) (10.6-12.3) (12.3-14.2) (13.6.15.8) (14.9.17.4) (16.2-19,0) (17.9-21.3) (19.2-23.0) I 30-dav I 8.60 10.2 12.0 13.4 16.3 16.7 18.0 19.4 21.1 22.4 J (8.07-9.17) (9.57-10.9) (11.3-12.8) (12.6-14.3) (14.3-16.31 (15.5.17.8) (16.8-19.2) (17.9-20,7) (19.5-22.7) (20.6-24.1) 45-day 107 7 12.7 1.4,8 16.4 18.4 19.9 21.4 22.7 245. 26.9 (10.1-11.4) (12.0-13.5) (13.9.15.7) (15.4-17.4) (17.3-19.5) (18.7-21.1) (20.0-22.7) -(21.2_24.2) I (227-26,2) (23.9-27,7) 60-day 12.6 14.8 17.1 18.8 20.9 22.4 23.9 25,3 27.1 28.4 (11.9-13.3) (14.0-15.6) (16.1-18.0) (17.7-19.8) (19.7-22.0) (21.1-23.7) (22.5-25.3) (23.7-26.8) (25.3-28.7) (26.4-30.2) 'Precipitation frequency(PF)estimates in this table are based on frequency analysis of partial duration series(PDS). Numbers in parenthesis are PF estimates at lower and upper bounds of the 90%confidence interval.The probability that precipitation frequency estimates I Iare (for a given duration and average recurrence interval)will be greater than the upper bound(or less than the lower bound)is 5%.Estimates at upper bounds not checked against probable maximum precipitation(PMP)estimates and may be higher than currently valid PMP values. Please refer to NOAH Atlas 14 document for more information. Back to Too 1 pi A. ill 1 http://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.htm l?lat=38.0253&Ion=-78.6538&dat... 11/21/2016 Precipitation Frequency Data Server Page 2 of 4 I PF graphical PDS-based depth-duration-frequency(DDF)curves t Latitude:38.0253°,Longitude:-78.6538° 30 II 1 41 1 1 1 1 1 1 41 1 r 1 Average recurrence interval 7,0„/ 25 -.. (years) — t 20 2er I o. 5 c 15 - — 25 y /'. f— 50 I a `� -- 100 .3 10 - :2. f "�lJ -� 200 � _',.. -.�.� 500 5 _ ...--__--- � ._..-•..""' — 1000 I _..- 0 -- Y 1 1 ft 1 1 1 1 1 1 11 ill G c c C cT >,T T T T T T T • .2- L L L L ry 4 43 47 �� E E E N b N N V� p 1(1 O tIf 1. O N R V S , r-r rl r�r1 '�D Duration 30 r 1 I 25 __ i �r c i --j! Duration ao 20 i 5{nin 2-day l 0 15 - .-----"' — 10-min 3-day 15 min -- 4-day 0 L ..-4,-- a.. 30-min — 7-clay 1D ._ -" - — 6O-min — 10-day ,,.,..... ---'""� -- 2-hr — 20-day — 3-hr — 30-day 5 --_-- --m:' "--"------ _ - --- __ .'` '— 6-hr — 45-day _ -- ", — 12-hr — 50-day T r I _..---- 1 i 1 1 1 — 24-hr 01 2 5 10 25 50 100 200 500 1000 Average recurrence interval(years) NOAA Atlas 14,Volume 2,Version 3 Created(GMT):Mon Nov 21 16:29:22 2016 Back to Top IN NM Ma i IN Mk http://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?tat=38.0253&ton=-78.6538&dat... 11/21/2016 Precipitation Frequency Data Server Page 3 of 4 Maps & aerials Small scale terrain �SQ Ott tlAl MOUNTAIN 1 g A Batesville ,l Large scale terrain • • Washington, D.C." ti as monbutg. Stam- • �•� VIRGINIA vtA Richrt1ond • d • Lyntury s<kthurt Roanoke Nott Large scale map x't Washington Harrisonburg Richt 'nfl Lyndibrug `I- !( Blacksburg Rovtoke — tUUkm T 60nu Na http://hdsc.nws.noaa.gov/hdsc/pfds/pfdsj,rintpage.htm l?lat=38.0253&ion=-78.653 8&dat... 11/21/2016 Precipitation Frequency Data Server Page 4 of 4 I La !e scale aerial t Hnill m,_>h n ISI n,;nl. : ill'. Al I • • • it�„ Back to Too US Department of Commerce National Oceanic and Atmospheric Administration National Weather Service National Water Center 1325 East West Highway Silver Spring,MD 20910 Questions? HDSC.Questionst noaa.aov Disclaimer 1 aft 1 I sr oft http://hdsc.nws.noaa.gov/hdsc/pfds/pfdsJrintpage.htm l?lat=38.0253&lon=-78.6538&dat... 11/21/2016 i