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HomeMy WebLinkAboutWPO202000028 Stormwater Management Maintenance Agree. 2022-09-15SHIMP ENGINEERING, P.C. Design Focused Engineering Stormwater Management Plan Calculation Packet Project Name: REGENTS SCHOOL OF CHARLOTTESVILLE — STORM MANAGEMENT. Prepared by: Shimp Engineering P.C. Date: September 14, 2022 2 n t.. SF 1P 9 45 83 14R-L Al- SHIMP ENGINEERING, P.C. Design Focused Engineering Table of Contents Cover Page Table of Contents Project Narrative Project Description Stormwater Quality Calculations: Post -Development VRRM Map Post -Development VRRM Spreadsheet. Pre - Development Stormwater Management Calculations: Pre -Development HydroCAD Analysis POA - B. Pre -Development Time of Concentration Calculations TOC Nomographs Post - Development Stormwater Management Calculations: Post -Development HydroCAD Analysis POA - B. Post -Development Time of Concentration Calculations TOC Nomographs Independent Reports: NRCS Soils Report NOAA Precipitation Report SHIMP ENGINEERING, P.C. Design Famsed Engineering September 14, 2022 Albemarle County Regarding: Regents School of Charlottesville Stormwater Management Plan WP0202000028 Amendment Proiect Description The purpose of this project is to develop a private school with multiple small buildings and a recreation area on what is currently undeveloped land off of reservoir Road. The development property has an area of 19.11 acres and development will disturb a total area total area of 9.55 Acres. Runoff from the site is analyzed at two points, labeled POA A and POA B. The proposed stormwater design for the point POA A meets water quality requirement set forth in 9VAC25-870-66-B. La and 9VAC25-870-66.C.3.a. and for the point POA B meets 9VAC25-870-66. B.3.a. and 9VAC25-870-66. C.2.b. VSMPAmendment Description: WPO202000028 Regents school of Charlottesville, was approved on December 16 2021. This amendment increased (LOD) Limits of Disturbance area by 0.79 acres, the scope of this amendment adds a large athletic field, a small warm-up field and the additional classrooms, located adjacent to the athletic field. SKMQaantity The requirements for stormwater quantity are satisfied by analyzing concentrated runoff from the development to the two points, labeled POA A and POA B. The drainage area to POA A at Moores creek stream is located at the south of the property. The drainage area to POA A was analyzed and found to be in compliance with the channel protection requirements 9VAC25-870-66-B.l.a and flood protection requirements 9VAC25-870-66.C.3.a. Runoff from this drainage area is conveyed in a riprap channel to the manmade portion of stream mentioned above, where it is less than 1% of the overall drainage area at that point. Sheet C6 shows the delineation of site area versus total drainage area to POA A in Moores creek. The drainage area to POA B was analyzed and found to be in compliance with channel protection requirement 9VAC25-870-66-B.3.a and flood protection requirements 9VAC25-870-66-C.2.b. Runoff from this drainage area is conveyed in a pipe and outlets to a natural stream which eventually drains into Moores creek at rates which satisfies the energy Balance. The post development 10yr, 24 hr. peak flow rate to POA B is less than Pre -Development. 7���:i��3.1:L•Z•P Energy Balance Equation Summary: POA B (POND ) 24 Hr 1 year Storm Comparison: Qe eDWzI.F.'(Qp.d.,.uv.e'RVemow.ao.e)/Rv,_b Qaeve�un` (�we'RVrwewel/Rvan.oae Limits Disturbance = 9.55 ' Acres Qp.m.ebp.a = 10. RV�ce_W = Max Qw v = 0 58 ch RVm,. Achieved Past-Dev Max Runoff Qrw — 0.43 ds. Site complies with 9VAC25-R70868(3) Max. DID, — 5.70 cis (predev) Achieved Digr — 3.26 cis Site camplies with 9VAC2587D86C(3)b SHIMP ENGINEERING, P.C. Design Focused Engineering SWM OunliJy To satisfy water quality requirements., 5.48 acres of the property has been placed within a forest and open space/ SWM Easement. 9VAC25-870-65 Requires that the total phosphorous (TP) nutrient reduction required by the site development be treated in accordance with the VRRM New development spreadsheet reduction requirements. Per the VRRM New Development Spreadsheet, the new total TP reduction required for the site is 3.51 lbs./yr., the original design required 2.79 lbs./yr., to address this, and additional 0.72 lbs./yr., nutrient credits will be purchased from the same nutrient bank. This additional amount was caused by the addition of 0.27 ac Turf and 0.41 Ac impervious to the project area. SHIMP ENGINEERING, P.C. Design Focused Engineering Stormwater Quality Calculations: Post -Development VRRM Map Post -Development VRRM Spreadsheet. 0 '0 ox, O ° 0I 0O 0 � �0°0Q°G 000 °0 0�00�000C O 0 QO 0qO 0 000 O 0 O\ 000< O 0. 00o 000 ° 00ou00 �0 Ogo00 oOg0 O ♦� 00000 �o \ O O O m \ 10 �0 0 00C SIG ° O D.B. 4110, rn. __ TM 75-59 ZONE: R1 RESIDENTIAL USE: SINGLE FAMILY RESIDENTIAL AREA DEDICATED TO ALBEMARLE C01Tot B. 660, PG. 774 SSG B O O� O OOO� O Q�°00 R � �j ° 0 C 0 OGT O O N/F O\O O SF N/F I UNIVERSITY OF VIRGINIA FOUNDATION CIL JOHNSON D.B. 4170, PG. 689 /1) O R(, / TM 7RESID r D. C. 1% 7 PG. 722 O O O O R ' o / ZONE: Rt RESIDENTIAL 11K 76-14 TM 7RESID SINGLE FAMILY RESIDENTIAL � ZONE: R1A@ESIDENTIAL ' SINGLE FA Y RESIDENTIAL ZONE: RI RESIDENTIAL .. O 0 Q q /Y o ._ a � � N �B�rk� E USE: SINGLE FAMILY RESIDENTIAL Q O 0 0 0 0 0 u* •t Q O Q 0, O Q 4T0yr y. ----- - t� si RE e I�RQAD --- - -- / -tr AREA DEDICATED TO gLBEAgLE COUNT'1� PER INST# 202200003247 S2S Q Q ° ! 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O 00 0O00o0O O u:;;;:::::;;;: Project Engineer + O O O Q FOo Shimp Engineering, P.C. ° Q° 0 O 0 0 Q O �':Lov-►�. �oov 1 9 D 912 East High St. Charlottesville, VA 22902 '® O ° 0 Q O O 0 O o� Via email to' KendraCaDShimp-Engineering.com a te° O� O Q O /: H S G B Poo O O 0 A Q Q . ,n With a copy to: �N O Q Q °o LIMITS OF DISTURBANCE AREA Courtney Palumbo (cpal umho�iients-schooLol'e Q O O �t 9.55 ACRES Owner: Regents School of Charlottesville Inc. _�P' � O�RO�� 0 0 O :o Contact: Courtney Palumbo (cualumboii rceents-schOol.orB) �O Q Project: Regents School of Charlottesville 0 O /' Project No.: 18.020 Q O (O :6 DEQ SWM No.: O Location: Near 1 155 Reservoir Road Charlottesville, VA 22903 +� 00, O Q O Coordinates: (38.024612, -78.538353) �C Legal Reference: TMP 75-66 & 76-17 \+ O O a` Receiving Water: Moores Creek HUC12: 020802040402 Estimated Credits Required: 2.79 lb Dear Kendra and Courtney. This letter is to confirm the availability to your project (referenced above ) of authorized Nutrient Credits sufficient to meet the your above referenced estimated requirements of Nutrient Credits at our Rivanna River nutrient offset credit bank facility (the "Bank"). The Bank has been registered with the Virginia Department of Environmental Quality (DEQ). These Nutrient Credits are generated and managed under the terms of the Reduction Implementation Plan for the Bank dated November 2017. which was authorized by (DEQ) on September 5, 2018. The Bank has been authorized to provide Nutrient Credits for use in the James River watershed. These credits are transferable to those entities regulated under DEQ's Storm Water Management program in accordance with VA Code 62.1-44.15:27. If we can provide furl assistance please feel free to contact our office. Hotel Sir ital, LLC. Bank Sponsor By ana l r lk REGENTS SCHOOL ::11 11_' LEGEND El VRRM-TURF - LOD VRRM - IMPERV. Open Space/ SWM Easement 71 River Nutrient Offset Trading Bank, 31 Garrett Street, Warrenton, Virginia 20186 V N/F / DAVID HARLOW D.B. TM 7 PG. 154 TM 75-61 ZONE: R1 RESIDENTI USE: SINGLE FAMILY R I NTIAL N /F / / RICH ARD SHRUM / D.B. 2678, PG. 194 TM 75-60 / ZONE: R1 RESIDENTIAL USE: SINGLE FAMILY RESIDENTIAL / 7 � N/F TON DINH D B 4415 PG. 7 AMENDMENT : REVISE CREDIT LPURCHASE TO 3.51 LBS/YR 100 80 0 80 160 240 Graphic Scale: 1 "=80' 15' PRIVATE SANITARY SEWER EASEMENT b8" 611 PG 639 0 0 ° 0I Runoff Coefficients IRv) Asoik BSolis CSoils DSoik Forest/Open Spare 0.02 003 Od4 0.05 ManageciTud 0.15 020 022 0.25 Impervious Cover 0.95 095 0.95 0.95 SA8 SAS Treatment Volume (acre-R) Treatment volume(cubk feet) TP load (Ib/Tr) TN Load llb/vr) Infarmatlmal Pu eus ON 15,391 9.67 69.18 0.09 36% 6.65 0.20 44% 2.89 0.95 719% 15.(12 028 I \V X Project Name: Repots School Date: 11 9/13/2022 BMP Design SperiTrratiars tat: 2013 Draft Stds & Specs Site Information Post -Development Project (Treatment Volume and Loads) Land Cover (acres( A Soils BSmi, CSoils DSoils Totals rarest/Ocen Space lacresl - undinurbed, rated form o ens are ormforested 5.49 5.48 ManagiMTud (acres) -disturbed, graded torliamsmotherwrUtobe 6.65 6.65 Impervous Cower (acres) 2.89 2.89 •Porest/Opea Spaceamas must bepmIKWdm aw"ance vdth Me 14Mmp RulWfRad mion Merhad 15.02 Constants Annual Rainfall (Inches) 43 Target Rainfall Event(Inches) 1110 Total Phosphomi(TP)EM-(mg/U 026 Total Nitrogen (TN) EMC ( 1B6 Target TP Loatl(Ib/acre/Vd OAS Pj(unitlesscorrecuonfacnsr) 090 Forest/Open Space Caver (acres) Weighted Rv (forest) %Forest Ma raged Turf Cover (acres) Weighted Rv (turf) % Managed Turf Impervious Cover acres) Rv (impervious) %Impervious Ste Area (acres) Site Rv R <01 \\ :w1 ��A 1� n data inputcelk constantvalues cakulation cells SHIMP ENGINEERING2. LAND PLANNING - PROJECT MANAGEMENT 912 E. HIGH ST. 434.227.5140 CHARLOTTESVILLE VA, 22902 JUSTIN@SHIMP-ENGINEERING.COM 1 Q;' JU SHIMP oAAa9S'IONAL VSMP PLAN AMENDMENT REGENTS SCHOOL ALBEMARLE COUNTY, VIRGINIA SUBMISSION: 2020.09.14 REVISION: FILE NO. 18.020 \ LAND USE MAP - C5_ DEQ Viryinia Runoff Reduction Method New Development Complionre Spreadsheet - Version 3.0 C 2011 ship Standards and Spedficadons 0 2013 Draft Basis Standards and Spedficadons Project Name: Regents Schaal Date: 9/13/2022 BMp Design specifications List. 2013 Draft Sods & Specs Site Information Post -Development Project (Treatment Volume and Loads) land Cover (acres) Asons BSons CSoils DSoils Totals Forest/Open span lacres)- undlsmrbed, protected foresVo a remrertM and 5.48 sm Managed Tun (acres) f d,oum,1, paded Mr ands or other curt to be mowed/man. d 6.65 6.65 Imperuiaus Ornehaoes) 2.89 -it L15.D2 'Foresr/Open spore areas must be protected in accordance wits the Viryinia Runoff Reduction Meahatl Constants Annual Rainfall (inches' 03 Target Rainfall Event hnches) S.W Total Phosphorus(TP) EMC(mg/E' 1 0.26 Total wmogen (TM' EMC (mg/4 1.86 Target m mad (m/aaeMl 0.41 Pi lumdess com ration famorl 0.90 ennnN rnarfrNenea foul ASoils BSoils Csolls Dsolls Forest/Open spare 0.02 0.03 0.04 0.85 ManagdTurf 0.15 0.20 0.22 0.25 Impereous cover 0.95 0.95 0.95 0.95 Forest/Open space Cover(soes) 5.48 Trea(aacreft)lume 0.3533 Treatment Volume (cubic feet) 15,391 TP Load(lb/yr) 9.67 TN mad QbyQ 69.18 IMa_.i.e. Pu oses Onl Weighted RV (forest) 0.03 %Forest 36% Managed Turf Cover(acres) 6.65 Weighted Rv (turf) 0.20 %Managed Turf 46% ImperviousC er(arms) 2.89 Rv(ImprM...) 0.95 %Impervious 19% Site area (acres) 15.02 Site RV 0.28 data input rellz nsmnt slues calculation cells Virginia Runoff Reduction Method Worksheet DEQ Virginia Runoff Reduction Method New Development Compliance Spreadsheet - Version 3.0 BMP Design Specifications List: 2013 Draft Stds & Specs Site Summary Project Title: Regents School Date: 44817 Total Rainfall = 43 inches Site Land Cover Summary A soils BSoils CSoils DSoils Totals % Total Forest/Open (acres) 0.00 5.48 0.00 0.00 5.48 36 Managed Turf (acres) 0.00 6.65 0.00 0.00 6.65 44 Impervious Cover (acres) 0.00 2.89 0.00 0.00 2.89 19 15.02 100 Site Tv and Land Cover Nutrient Loads Site Rv 0.28 Treatment Volume (ft') 15,391 TP Load (lb/yr) 9.67 TN Load (lb/yr) 69.18 Total TP Load Reduction Required (lb/yr) 3.51 Site Compliance Summary Total Runoff Volume Reduction (ft') 0 Total TP Load Reduction Achieved (lb/yr) 0.00 Total TN Load Reduction Achieved (lb/yr) 0.00 Remaining Post Development TP Load 9.67 (Ib/yr) Remaining TP Load Reduction (lb/yr) Required 3.51 Summary Print Virginia Runoff Reduction Method Worksheet Drainage Area Summary D.A. A D.A. B D.A. C D.A. D D.A. E Total Forest/Open (acres) 0.00 0.00 0.00 0.00 0.00 0.00 Managed Turf (acres) 0.00 0.00 0.00 0.00 0.00 0.00 Impervious Cover (acres) 0.00 0.00 0.00 0.00 0.00 0.00 Total Area (acres) 0.00 0.00 0.00 0.00 0.00 0.00 Drainage Area Compliance Summary D.A. A D.A. B D.A. C D.A. D D.A. E Total TP Load Reduced (lb/yr) 1 0.00 1 0.00 0.00 1 0.00 1 0.00 0.00 TN Load Reduced (lb/yr) 1 0.00 1 0.00 0.00 1 0.00 1 0.00 0.00 Summary Print SHIMP ENGINEERING, P.C. Design Focused Engineering Pre - Development Stormwater Management Calculations: Pre -Development HydroCAD Analysis POA - B. Pre -Development Time of Concentration Calculations TOC Nomographs PRE-DEV HYDROCAD ANALYSIS POA - B 1S PRE_DRAI Sub4 Reach Aon Llflk AGE AREA 2L PRE-DEV HYDROCAD ANALYSIS POA - B PreDev POINT B- 9 - 13 - 2022 Type 1124-hr 1 yr Rainfall=3.05" Prepared by {enter your company name here} Printed 9/14/2022 HydroCADO 9.10 s/n 07054 © 2010 HydroCAD Software Solutions LLC Page 2 Time span=0.00-48.00 hrs, dt=0.05 hrs, 961 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method SubcatchmentlS:PRE_DRAINAGEAREA Runoff Area=3.550ac 0.00%Impervious Runoff Depth=0.29" Tc=17.9 min CN=58 Runoff=0.58 cfs 0.086 of Link 2L: POA B Inflow=0.58 cfs 0.086 of Primary=0.58 cfs 0.086 of Total Runoff Area = 3.550 ac Runoff Volume = 0.086 of Average Runoff Depth = 0.29" 100.00% Pervious = 3.550 ac 0.00% Impervious = 0.000 ac PreDev POINT B- 9 - 13 - 2022 Prepared company name here} PRE-DEV HYDROCAD ANALYSIS POA - B Type 11 24-hr 1 yr Rainfall=3.05" Printed 9/14/2022 Summary for Subcatchment 1S: PRE —DRAINAGE AREA Runoff = 0.58 cfs @ 12.18 hrs, Volume= 0.086 af, Depth= 0.29" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 1 yr Rainfall=3.05" Area (ac) CN Description 0.540 61 >75% Grass cover, Good, HSG B 3.010 58 Woods/grass comb., Good, HSG B 3.550 58 Weighted Average 3.550 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.9 Direct Entry, Summary for Link 2L: POA B Inflow Area = 3.550 ac, 0.00% Impervious, Inflow Depth = 0.29" for 1 yr event Inflow = 0.58 cfs @ 12.18 hrs, Volume= 0.086 of Primary = 0.58 cfs @ 12.18 hrs, Volume= 0.086 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs PRE-DEV HYDROCAD ANALYSIS POA - B PreDev POINT B- 9 - 13 - 2022 Type 1124-hr 10 yr Rainfall=5.57" Prepared by {enter your company name here} Printed 9/14/2022 HydroCADO 9.10 s/n 07054 © 2010 HydroCAD Software Solutions LLC Page 4 Time span=0.00-48.00 hrs, dt=0.05 hrs, 961 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method SubcatchmentlS:PRE_DRAINAGEAREA Runoff Area=3.550ac 0.00%Impervious Runoff Depth=1.50" Tc=17.9 min CN=58 Runoff=5.70 cfs 0.442 of Link 2L: POA B Inflow=5.70 cfs 0.442 of Primary=5.70 cfs 0.442 of Total Runoff Area = 3.550 ac Runoff Volume = 0.442 of Average Runoff Depth = 1.50' 100.00% Pervious = 3.550 ac 0.00% Impervious = 0.000 ac PreDev POINT B- 9 - 13 - 2022 Prepared company name here} PRE-DEV HYDROCAD ANALYSIS POA - B Type 11 24-hr 10 yr Rainfall=5.57" Printed 9/14/2022 Summary for Subcatchment 1S: PRE —DRAINAGE AREA Runoff = 5.70 cfs @ 12.12 hrs, Volume= 0.442 af, Depth= 1.50" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 10 yr Rainfall=5.57" Area (ac) CN Description 0.540 61 >75% Grass cover, Good, HSG B 3.010 58 Woods/grass comb., Good, HSG B 3.550 58 Weighted Average 3.550 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.9 Direct Entry, Summary for Link 2L: POA B Inflow Area = 3.550 ac, 0.00% Impervious, Inflow Depth = 1.50" for 10 yr event Inflow = 5.70 cfs @ 12.12 hrs, Volume= 0.442 of Primary = 5.70 cfs @ 12.12 hrs, Volume= 0.442 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs PRE-DEV HYDROCAD ANALYSIS POA - B PreDev POINT B- 9 - 13 - 2022 Type 1124-hr 100 yr Rainfall=9.15" Prepared by {enter your company name here} Printed 9/14/2022 HydroCADO 9.10 s/n 07054 © 2010 HydroCAD Software Solutions LLC Page 6 Time span=0.00-48.00 hrs, dt=0.05 hrs, 961 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method SubcatchmentlS:PRE_DRAINAGEAREA Runoff Area=3.550ac 0.00%Impervious Runoff Depth=3.97" Tc=17.9 min CN=58 Runoff=16.42 cfs 1.174 of Link 2L: POA B Inflow=16.42 cfs 1.174 of Primary=16.42 cfs 1.174 of Total Runoff Area = 3.550 ac Runoff Volume = 1.174 of Average Runoff Depth = 3.97" 100.00% Pervious = 3.550 ac 0.00% Impervious = 0.000 ac PreDev POINT B- 9 - 13 - 2022 Prepared company name here} PRE-DEV HYDROCAD ANALYSIS POA - B Type/1 24-hr 100 yr Rainfall=9.15" Printed 9/14/2022 Summary for Subcatchment 1S: PRE —DRAINAGE AREA Runoff = 16.42 cfs @ 12.11 hrs, Volume= 1.174 af, Depth= 3.97" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 100 yr Rainfall=9.15" Area (ac) CN Description 0.540 61 >75% Grass cover, Good, HSG B 3.010 58 Woods/grass comb., Good, HSG B 3.550 58 Weighted Average 3.550 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.9 Direct Entry, Summary for Link 2L: POA B Inflow Area = 3.550 ac, 0.00% Impervious, Inflow Depth = 3.97" for 100 yr event Inflow = 16.42 cfs @ 12.11 hrs, Volume= 1.174 of Primary = 16.42 cfs @ 12.11 hrs, Volume= 1.174 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs REGENTS SCHOOL OF CHARLOTTESVILLE Time of Concentration Calculations PREDEV TOC_ POA B 100 ft Overland Flow 7.50%1 slope 1 0.33 C-value 10.4 min ISeelye Chart 765.0 ft S.C. Flow 12.00% slop I 1.7 fps ivelocity 7.5 min. NEH Figure 15-4 0.0 ft Channel 1 0.0 ft 1height 0.0 min. Kirpich Chart TOC= 17.9 min. 35 30 ;v Paved 9 z 25 o .e 300 Bore o 20 in w 200 Soil 6 r Poor Grass W z \Surface U-,5 w w Average = .a z 0.5 w z — u_ f005 Grass U 1.0 0 15 w .� z — 90 e � 20 In / 800 Grass z a 0 z/ 0 I N 60 � \� 10 w � a ¢ 50 '` /� 20 a w v V -J = 40 10 zz 0 x 30 9 w z w z 8 — 20 7 10 6 OVERLAND FLOW TIME (Seelye Chart) Source: Data Book for Civil Engineers. E.E. Seelye Plate 5-1 1.00 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.09 0. 0.08 0.07 e 0.06 0.05 0.04 0.03 0.02 0.01 0.005 0 2 ci c� v 1c i- 00 a o N as v� ro ti m a o d d d d d ddd.: Velocity (f fs) SHIMP ENGINEERING, P.C. Design Focused Engineering Post - Development Stormwater Management Calculations: Post -Development HydroCAD Analysis POA - B. Post -Development Time of Concentration Calculations TOC Nomographs POST-DEV HYDROCAD ANALYSIS POA - B 1S POST -DRAINAGE AREA 2L POA B Subcat Reach on Link Drainage Diagram for PostDev POINT B - 9 -13 - 2022 FpHydroCADO repared by {enter your company name here}, Printed 9/14/2022 9.10 s/n 07054 0 2010 HydroCAD Software Solutions LLC PostDev POINT B - 9 -13 - 2022 Prepared by {enter your company name here} POST-DEV HYDROCAD ANALYSIS POA - B Type 11 24-hr 1 yr Rainfall=3.05" Printed 9/14/2022 Time span=0.00-48.00 hrs, dt=0.05 hrs, 961 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method SubcatchmentlS:POST_DRAINAGEAREA Runoff Area=1.700ac 0.00%Impervious Runoff Depth=0.35" Tc=16.2 min CN=60 Runoff=0.43 cfs 0.050 of Link 2L: POA B Inflow=0.43 cfs 0.050 of Primary=0.43 cfs 0.050 of Total Runoff Area = 1.700 ac Runoff Volume = 0.050 of Average Runoff Depth = 0.35" 100.00% Pervious = 1.700 ac 0.00% Impervious = 0.000 ac PostDev POINT B - 9 -13 - 2022 Prepared by {enter your company name here} POST-DEV HYDROCAD ANALYSIS POA - B Type 11 24-hr 1 yr Rainfall=3.05" Printed 9/14/2022 Summary for Subcatchment 1S: POST —DRAINAGE AREA Runoff = 0.43 cfs @ 12.14 hrs, Volume= 0.050 af, Depth= 0.35" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 1 yr Rainfall=3.05" Area (ac) CN Description 1.290 61 >75% Grass cover, Good, HSG B 0.410 58 Meadow, non -grazed, HSG B 1.700 60 Weighted Average 1.700 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 16.2 Direct Entry, Summary for Link 2L: POA B Inflow Area = 1.700 ac, 0.00% Impervious, Inflow Depth = 0.35" for 1 yr event Inflow = 0.43 cfs @ 12.14 hrs, Volume= 0.050 of Primary = 0.43 cfs @ 12.14 hrs, Volume= 0.050 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs PostDev POINT B - 9 -13 - 2022 Prepared by {enter your company name here} POST-DEV HYDROCAD ANALYSIS POA - B Type 11 24-hr 10 yr Rainfall=5.57" Printed 9/14/2022 Time span=0.00-48.00 hrs, dt=0.05 hrs, 961 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method SubcatchmentlS:POST_DRAINAGEAREA Runoff Area=1.700ac 0.00%Impervious Runoff Depth=1.65" Tc=16.2 min CN=60 Runoff=3.26 cfs 0.233 of Link 2L: POA B Inflow=3.26 cfs 0.233 of Primary=3.26 cfs 0.233 of Total Runoff Area = 1.700 ac Runoff Volume = 0.233 of Average Runoff Depth = 1.65' 100.00% Pervious = 1.700 ac 0.00% Impervious = 0.000 ac PostDev POINT B - 9 -13 - 2022 Prepared by {enter your company name here} POST-DEV HYDROCAD ANALYSIS POA - B Type 11 24-hr 10 yr Rainfall=5.57" Printed 9/14/2022 Summary for Subcatchment 1S: POST —DRAINAGE AREA Runoff = 3.26 cfs @ 12.10 hrs, Volume= 0.233 af, Depth= 1.65" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 10 yr Rainfall=5.57" Area (ac) CN Description 1.290 61 >75% Grass cover, Good, HSG B 0.410 58 Meadow, non -grazed, HSG B 1.700 60 Weighted Average 1.700 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 16.2 Direct Entry, Summary for Link 2L: POA B Inflow Area = 1.700 ac, 0.00% Impervious, Inflow Depth = 1.65" for 10 yr event Inflow = 3.26 cfs @ 12.10 hrs, Volume= 0.233 of Primary = 3.26 cfs @ 12.10 hrs, Volume= 0.233 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs PostDev POINT B - 9 -13 - 2022 Prepared by {enter your company name here} POST-DEV HYDROCAD ANALYSIS POA - B Type/1 24-hr 100 yr Rainfall=9.15" Printed 9/14/2022 Time span=0.00-48.00 hrs, dt=0.05 hrs, 961 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method SubcatchmentlS:POST_DRAINAGEAREA Runoff Area=1.700ac 0.00%Impervious Runoff Depth=4.22" Tc=16.2 min CN=60 Runoff=8.84 cfs 0.598 of Link 2L: POA B Inflow=8.84 cfs 0.598 of Primary=8.84 cfs 0.598 of Total Runoff Area = 1.700 ac Runoff Volume = 0.598 of Average Runoff Depth = 4.22" 100.00% Pervious = 1.700 ac 0.00% Impervious = 0.000 ac PostDev POINT B - 9 -13 - 2022 Prepared by {enter your company name here} POST-DEV HYDROCAD ANALYSIS POA - B Type/1 24-hr 100 yr Rainfall=9.15" Printed 9/14/2022 Summary for Subcatchment 1S: POST —DRAINAGE AREA Runoff = 8.84 cfs @ 12.09 hrs, Volume= 0.598 af, Depth= 4.22" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 100 yr Rainfall=9.15" Area (ac) CN Description 1.290 61 >75% Grass cover, Good, HSG B 0.410 58 Meadow, non -grazed, HSG B 1.700 60 Weighted Average 1.700 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 16.2 Direct Entry, Summary for Link 2L: POA B Inflow Area = 1.700 ac, 0.00% Impervious, Inflow Depth = 4.22" for 100 yr event Inflow = 8.84 cfs @ 12.09 hrs, Volume= 0.598 of Primary = 8.84 cfs @ 12.09 hrs, Volume= 0.598 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs REGENTS SCHOOL OF CHARLOTTESVILLE Time of Concentration Calculations POSTDEV TOC _ POA B 100 ft Overland Flow 1.00%1 slope 1 0.33 C-value 15.0 min ISeelye Chart 50.0 ft S.C. Flow 1.00% slope 0.7 fps velocity 1.2 min. INEH Figure 15-4 0.0 ft Channel I 1 0.0 ft 1height 0.0 min. I Kirpich Chart TOC= 16.2 min. 35 30 Paved y z 25 o .e 300 c� Bare o 2 Cn 200 Sol \ Poor Grass z Surface U-.5 w Average = .a z 0.5 w z U- Grass U a. w Z gp 9 \ O 2A J N/ / / H a Dense Grass \ a r Z o 70 z \� 5.0 Z �- n 60 / 10 ¢ cr 50 '` 20 a w v U 40 10 0 U 2 30 9 w Z W J Z J � S 20 7 10 6 OVERLAND FLOW TIME (Seelye Chart) Source: Data Book for Civil Engineers, E.E. Seelye Plate 5-1 1.00 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10 0.09 0.08 0.07 e 0.06 0.05 0.04 0.03 0.02 0.01 0.005 L 0 2 Velocity (ft(s) SHIMP ENGINEERING, P.0 Design Focused Engineering Independent Reports: NRCS Soils Report NOAA Precipitation Report Custom Soil Resource Report Soil Map II 1-n - II• thi- .I nslm namo 715= 715= Mn nmm n 3 Map Soale: 1:5,M W pnntad m A landwpe (11'• x 8.57) dle t. N Meb3s 0 50 100 200 300 AFeet o za 500 ,aoo 1500 Mapprojacth:Web Maomr Cornermordnktm:WGS84 E*ptu:UTMZo 17NW(S84 9 moo ne100 7182Do ]imm nw nm p 3d°1'3YN F 3 1'12N nmm 3 MAPLEGEND Area of Interest (AOQ O Area of Interest (AOI) Solis Soil Map Unit Polygons N Soil Map Unit Lines Soil Map Unit Points Special Point Features V Blowout ® Borrow Pit Clay Spot O Closed Depression Gravel Pit Gravelly Spot O Landfill A. Lava Flow Marsh or swamp Mine or Quarry O Miscellaneous Water O Perennial Water y Rock Outcrop + Saline Spot Sandy Spot Severely Eroded Spot Q Sinkhole Slide or Slip J, Sodic Spot Custom Soil Resource Report MAP INFORMATION g Spoil Area The soil surveys that comprise your AOI were mapped at 1:15,800. o Stony Spot W Very Stony Spot Warning: Soil Map may not be valid at this scale. wet Spot Enlargement of maps beyond the scale of mapping can cause Other misunderstanding of the detail of mapping and accuracy of soil Special Line Features line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed Water Features scale. Streams and Canals Transportation Please rely on the bar scale on each map sheet for map �..ry Rails measurements. N Interstate Highways Source of Map: Natural Resources Conservation Service ti US Routes Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Major Roads Local Roads Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts Background distance and area. A projection that preserves area, such as the . Aerial Photography Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Albemarle County, Virginia Survey Area Data: Version 13, Sep 17, 2019 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: May 20, 2019—Aug 1, 2019 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. 10 Custom Soil Resource Report Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 14C Chester loam, 7 to 15 percent 3.0 4.3% slopes 14D Chester loam, 15 to 25 percent 1.7 2.5% slopes 14E Chester loam, 25 to 45 percent 7.9 11.4% slopes 19B Minnieville loam, 2 to 7 percent 9.8 14.1% slopes 19C Minnieville loam, 7 to 15 6.5 9.3% percent slopes 19D Minnieville loam, 15 to 25 22.1 31.8% percent slopes 36B Hayesville loam, 2 to 7 percent 2.0 2.8% slopes 36C Hayewille loam, 7 to 15 percent 7.5 10.7% slopes 56B Meadowville loam, 2 to 7 0.3 0.4% percent slopes 77 Dan River-Codorus complex, 0 8.8 12.6% to 2 percent slopes, occasionally flooded Totals for Area of Interest 69.4 100.0% Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a 11 Custom Soil Resource Report Albemarle County, Virginia 14C—Chester loam, 7 to 15 percent slopes Map Unit Setting National map unit symbol: kb81 Mean annual precipitation: 25 to 65 inches Mean annual air temperature: 54 to 59 degrees F Frost -free period: 195 to 231 days Farmland classification: Farmland of statewide importance Map Unit Composition Chester and similar soils: 80 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Chester Setting Landform: Hillslopes Landform position (two-dimensional): Summit Landform position (three-dimensional): Interfluve Down -slope shape: Convex Across -slope shape: Convex Parent material: Residuum weathered from granite and gneiss Typical profile H1 - 0 to 7 inches: loam H2 - 7 to 41 inches: clay loam H3 - 41 to 79 inches: loam Properties and qualities Slope: 7 to 15 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Moderate (about 6.9 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 3e Hydrologic Soil Group: B Hydric soil rating: No 14 Custom Soil Resource Report 14D—Chester loam, 15 to 25 percent slopes Map Unit Setting National map unit symbol: kb82 Mean annual precipitation: 25 to 65 inches Mean annual air temperature: 54 to 59 degrees F Frost -free period: 195 to 231 days Farmland classification: Farmland of statewide importance Map Unit Composition Chester and similarsoils: 80 percent Estimates are based on observations, Description of Chester descriptions, and transects of the mapunit. Setting Landform: Hillslopes Landform position (two-dimensional): Summit Landform position (three-dimensional): Interfluve Down -slope shape: Convex Across -slope shape: Convex Parent material: Residuum weathered from granite and gneiss Typical profile H1 - 0 to 7 inches: loam H2 - 7 to 41 inches: clay loam H3 - 41 to 79 inches: loam Properties and qualities Slope: 15 to 25 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: High Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Moderate (about 6.9 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 4e Hydrologic Soil Group: B Hydric soil rating: No 15 Custom Soil Resource Report 14E—Chester loam, 25 to 45 percent slopes Map Unit Setting National map unit symbol: kb83 Mean annual precipitation: 25 to 65 inches Mean annual air temperature: 54 to 59 degrees F Frost -free period: 195 to 231 days Farmland classification: Not prime farmland Map Unit Composition Chester and similarsoils: 75 percent Estimates are based on observations, Description of Chester descriptions, and transects of the mapunit. Setting Landform: Hillslopes Landform position (two-dimensional): Summit Landform position (three-dimensional): Interfluve Down -slope shape: Convex Across -slope shape: Convex Parent material: Residuum weathered from granite and gneiss Typical profile H1 - 0 to 7 inches: loam H2 - 7 to 41 inches: clay loam H3 - 41 to 79 inches: loam Properties and qualities Slope: 25 to 45 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: High Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Moderate (about 6.9 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 7e Hydrologic Soil Group: B Hydric soil rating: No Custom Soil Resource Report 1913—Minnieville loam, 2 to 7 percent slopes Map Unit Setting National map unit symbol: 2v7hq Elevation: 360 to 1,540 feet Mean annual precipitation: 25 to 65 inches Mean annual air temperature: 54 to 59 degrees F Frost -free period: 195 to 231 days Farmland classification: All areas are prime farmland Map Unit Composition Minnieville and similar soils: 80 percent Estimates are based on observations, descriptions, and transacts of the mapunit. Description of Minnieville Setting Landform: Hillslopes Landform position (two-dimensional): Summit Landform position (three-dimensional): Interfluve Down -slope shape: Convex Across -slope shape: Convex Parent material: Residuum weathered from acid and basic igneous rock Typical profile Ap - 0 to 8 inches: loam Bt - 8 to 60 inches: clay C - 60 to 67 inches: clay Cr- 67 to 79 inches: bedrock Properties and qualities Slope: 2 to 7 percent Depth to restrictive feature: 60 to 120 inches to paralithic bedrock Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Very low to moderately high (0.00 to 0.20 iNhr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Moderate (about 7.6 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 2e Hydrologic Soil Group: B Hydric soil rating: No IVA Custom Soil Resource Report 19C—Minnieville loam, 7 to 15 percent slopes Map Unit Setting National map unit symbol: 2v7hr Elevation: 360 to 1,540 feet Mean annual precipitation: 25 to 65 inches Mean annual air temperature: 54 to 59 degrees F Frost -free period: 195 to 231 days Farmland classification: Farmland of statewide importance Map Unit Composition Minnieville and similar soils: 80 percent Estimates are based on observations, descriptions, and transacts of the mapunit. Description of Minnieville Setting Landform: Hillslopes Landform position (two-dimensional): Summit Landform position (three-dimensional): Interfluve Down -slope shape: Convex Across -slope shape: Convex Parent material: Residuum weathered from acid and basic igneous rock Typical profile Ap - 0 to 8 inches: loam Bt - 8 to 60 inches: clay C - 60 to 67 inches: clay Cr- 67 to 79 inches: bedrock Properties and qualities Slope: 7 to 15 percent Depth to restrictive feature: 60 to 120 inches to paralithic bedrock Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Very low to moderately high (0.00 to 0.20 iNhr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Moderate (about 7.6 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 3e Hydrologic Soil Group: B Hydric soil rating: No iV Custom Soil Resource Report 19D—Minnieville loam, 15 to 25 percent slopes Map Unit Setting National map unit symbol: 2v7hs Elevation: 360 to 1,540 feet Mean annual precipitation: 25 to 65 inches Mean annual air temperature: 54 to 59 degrees F Frost -free period: 195 to 231 days Farmland classification: Farmland of statewide importance Map Unit Composition Minnieville and similar soils: 80 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Minnieville Setting Landform: Hillslopes Landform position (two-dimensional): Summit Landform position (three-dimensional): Interfluve Down -slope shape: Convex Across -slope shape: Convex Parent material: Residuum weathered from acid and basic igneous rock Typical profile Ap - 0 to 8 inches: loam Bt - 8 to 60 inches: clay C - 60 to 67 inches: clay Cr- 67 to 79 inches: bedrock Properties and qualities Slope: 15 to 25 percent Depth to restrictive feature: 60 to 120 inches to paralithic bedrock Natural drainage class: Well drained Runoff class: High Capacity of the most limiting layer to transmit water (Ksat): Very low to moderately high (0.00 to 0.20 iNhr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Moderate (about 7.6 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 4e Hydrologic Soil Group: B Hydric soil rating: No 19 Custom Soil Resource Report 36B—Hayesville loam, 2 to 7 percent slopes Map Unit Setting National map unit symbol: 2xxy2 Elevation: 360 to 1,540 feet Mean annual precipitation: 25 to 65 inches Mean annual air temperature: 54 to 59 degrees F Frost -free period: 195 to 231 days Farmland classification: All areas are prime farmland Map Unit Composition Hayesville and similar soils: 80 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Hayesville Setting Landform: Hillslopes Landform position (two-dimensional): Summit Landform position (three-dimensional): Interfluve Down -slope shape: Convex Across -slope shape: Convex Parent material: Residuum weathered from granite and gneiss Typical profile A - 0 to 7 inches: loam Bt - 7 to 58 inches: clay BC - 58 to 67 inches: sandy clay loam C - 67 to 83 inches: fine sandy loam Properties and qualities Slope: 2 to 7 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: High (about 10.6 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 2e Hydrologic Soil Group: B Hydric soil rating: No 20 Custom Soil Resource Report 36C—Hayesville loam, 7 to 15 percent slopes Map Unit Setting National map unit symbol: 2xxy4 Elevation: 360 to 1,540 feet Mean annual precipitation: 25 to 65 inches Mean annual air temperature: 54 to 59 degrees F Frost -free period: 195 to 231 days Farmland classification: Farmland of statewide importance Map Unit Composition Hayesville and similar soils: 80 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Hayesville Setting Landform: Hillslopes Landform position (two-dimensional): Summit Landform position (three-dimensional): Interfluve Down -slope shape: Convex Across -slope shape: Convex Parent material: Residuum weathered from granite and gneiss Typical profile A - 0 to 7 inches: loam Bt - 7 to 58 inches: clay BC - 58 to 67 inches: sandy clay loam C - 67 to 83 inches: fine sandy loam Properties and qualities Slope: 7 to 15 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: High (about 10.6 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 4e Hydrologic Soil Group: B Hydric soil rating: No 21 Custom Soil Resource Report 56B—Meadowville loam, 2 to 7 percent slopes Map Unit Setting National map unit symbol: 2xxyc Elevation: 360 to 1,540 feet Mean annual precipitation: 25 to 65 inches Mean annual air temperature: 54 to 59 degrees F Frost -free period: 195 to 231 days Farmland classification: All areas are prime farmland Map Unit Composition Meadowville and similar soils: 85 percent Minor components: 5 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Meadowville Setting Landform: Interfluves Landform position (two-dimensional): Summit Landform position (three-dimensional): Interfluve Down -slope shape: Convex Across -slope shape: Convex Parent material: Colluvium derived from igneous rock Typical profile A - 0 to 14 inches: loam Bt - 14 to 46 inches: loam 2C - 46 to 79 inches: loam Properties and qualities Slope: 2 to 7 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 5.95 in/hr) Depth to water table: About 36 to 60 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: High (about 10.0 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 2e Hydrologic Soil Group: A Hydric soil rating: No Minor Components Delila Percent of map unit: 5 percent PA Custom Soil Resource Report Landform: Drainageways Landform position (two-dimensional): Footslope Landform position (three-dimensional): Head slope, tread Down -slope shape: Concave Across -slope shape: Convex Hydric soil rating: Yes 77—Dan River-Codorus complex, 0 to 2 percent slopes, occasionally flooded Map Unit Setting National map unit symbol: 2v7k0 Elevation: 360 to 1,540 feet Mean annual precipitation: 25 to 65 inches Mean annual air temperature: 54 to 59 degrees F Frost -free period: 195 to 231 days Farmland classification: Prime farmland if drained and either protected from flooding or not frequently flooded during the growing season Map Unit Composition Dan river, occasionally flooded, and similar soils: 50 percent Codorus, occasionally flooded, and similar soils: 40 percent Minor components: 5 percent Estimates are based on observations, descriptions, and transacts of the mapunit. Description of Dan River, Occasionally Flooded Setting Landform: Flood plains Down -slope shape: Linear Across -slope shape: Linear Parent material: Alluvium derived from igneous rock Typical profile A - 0 to 12 inches: loam Bw - 12 to 35 inches: silt loam C - 35 to 79 inches: silt loam Properties and qualities Slope: 0 to 2 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: About 36 to 60 inches Frequency of flooding: Occasional Frequency of ponding: None Available water storage in profile: High (about 9.0 inches) 23 Custom Soil Resource Report Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 2w Hydrologic Soil Group: B Hydric soil rating: No Description of Codorus, Occasionally Flooded Setting Landform: Flood plains Down -slope shape: Linear Across -slope shape: Linear Parent material: Alluvium derived from igneous rock Typical profile A - 0 to 8 inches: silt loam BA - 8 to 16 inches: silt loam Bwl - 16 to 26 inches: silty clay loam Bw2 - 26 to 40 inches: silty clay loam Bw3 - 40 to 79 inches: silt loam Properties and qualities Slope: 0 to 2 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Somewhat poorly drained Runoff class: Very high Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: About 8 to 18 inches Frequency of flooding: Occasional Frequency of ponding: None Available water storage in profile: High (about 11.6 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 3w Hydrologic Soil Group: B/D Hydric soil rating: No Minor Components Hatboro, occasionally flooded Percent of map unit: 5 percent Landform: Flood plains Down -slope shape: Linear Across -slope shape: Linear Hydric soil rating: Yes 24 NOAA Atlas 14, Volume 2, Version 3 Location name: Charlottesville, Virginia, USA*`r Latitude: 38.0244°, Longitude:-78.5368° Elevation: 491.46 ft** 'source: ESRI Maps iA -" source: USGS POINT PRECIPITATION FREQUENCY ESTIMATES G.M. Bonin, D. Martin, B. Lin, T. Parzybok, M.Yekta. and D. Riley 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)t Average recurrence interval (years) Duretion 7 2 5 10 25 60 1 100 00 200 500 1000 0.492 5-min (0.3117-0391) (0.3078-0.465) (0.443-0.544) (OA96 0 611) (0.556-0686) (0.602-0..745) (0.642-0.80) (0.680-0852) (0.722-0 917) (0.755-0 972) 1.31 70-min (0.6-0624) 0 (0.605-0.0744) (0.709-0872) (0.793-0978) (0.8110) 86- (0.958-1.19) (1.021527) (1.08-21335) : (14-IA5) : (19-16 .53) 1. 75-min (0.32-0..780) (0.760-0935) (0. 977-1.10) (1.0-?24) (1. 2-21639) (1.21-11..50) (1.29-1..61) (1.0-516.71) 1 (1.44-1583) 1 (14 9- .92) 30-min (0.696207) 1 (1.05-1..29) 1 (1.274257) 1(1.45-279) (1.66-2605) (1.32526) (1.982.46) (2.2-2.65) (2.92391) (2.283.11) 1.20 60-min �62) �73) (1.08-1..33) (1.3 (1.63-2 01) (18 9-2.33) (2.2 (2. 8 3807) (2. 2 3839) (2.97-3.72) (3. 8-4.17) (35 3-4.54) 2.19 4.32 6.43 2-hr (1.26- 65) (1.53-1599) (1.92 2A9) (2.252.57 5-2.92) (2.67-3.47) (3.01 3793) (33 5-4.40) (3. 0-4.89) (4.15358) (4.54-6.17) 2.80 3.34 3-hr (1.38 $82) (1.67-220) (2.09 2975) (2.44-3.22) (2. 033.83) (3.27�33) (36 5-4.86) (a. 3-5.41) (a. 38.18) (49 5-6.83) 6-hr (1: 9-2.29) (2.176) (2.67 3343) (3134.03) (3.74-a.84) (4. 55253) (4: 86.27) (5.33-7807) (6.09�22) 8.18 (6.74-9.23) 12-hr (2F-2..92) 248) (2.71-3.51) (3.37�338) (3.975317) (4. 08.27) (5. -37225) 0 (63-8.32) (7.0297 (8.14--11.2) (9.12- 2.8) 205 4-hr (2.74-341) (3.32-4913) 71 (42 3-5.27) (4.99-6.21) (6.3-67560) (7. 0--84.80) 15 (8.0- 0.1) (9.06-11 .6) (10.6-13.8) (11.9-15.6) 2-0ey (32 3-4.01) (3.91-4587) (4.968.18) (5.82---7226) (7.03-8.81) (8.0210.1) (9.08- 1.5) (102- 3.1) (11.8- 5.4) (132-167.3) 3-day (3.48-423) (424155.13) (5.34851) (62 6- .64) (7.5 9?28) (8.64-0.6) (9.77- 2.1) (11.0-13.8) (12� 6.2) (14116- 8.2) 4-day : 3 (34.45) (4.515z39) 2 (5. -6.85) : 0 (6-8.02) (8.161 974) (9.25-111.2) (10.5- 2.7) (11.8-14A) (13.6- 6.9) (1511- 9.1) 7-day (4.34-5.13) (52 38.17) (6.52 7..72) (7.58-8.98) (9.0--10.8) (10.3- 2.3) (11.5-13.9) (129-15.7) (14.7- 8.2) (1613- 0.4) 10 dey (4.94-5..77) (5.948.93) (7.32 8.55) (8.43-9.0) (9.97--111.7) (11 2-13.2) (12.5-14.8) (138-16.6) (157- 9.0) (17.1--21.1) 20 dey (6.58- .50) (78 58.95) (9.47---10.8) (107- 2.3) (12.4-14.2) (1374 5.8) (15.1-1 4) (16.4 9.1) (182-21A) (19.5 3.2) 30 dey (8.129.15) (9.62- 0.8) (114-12.8) (127--14.3) (144-16.3) (187---17.8) (16.9-19.3) (18.1- 0.7) (19.722.7) (20.824.2) 45-day (102- 1.4) 1 (12.0- 3.4) 1 (14.0- 5.7) 1 (15.5-17.4) 1 (174$ 9.6) 1 (1821.2) 1 (2021' 2.7) (21424.3) (23?0-26.3) (242627.8) 60-day (12.0. 3.3) (141415.6) (162-18.o) (178 9.8) (19922.1) (213? 3.8) (22274--25.5) (2421--267.0) (25z7- 9.0) (26.8 0.5) 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 AOas 14 document for more information. Back to Top PF graphical