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HomeMy WebLinkAboutWPO201900054 Calculations 2021-10-25WAHS Site Improvements ALBEMARLE COUNTY, VIRGINIA SCOTTSVILLE DISTRICT DESIGN CALCULATIONS & NARRATIVE WPO 2019-00054 SEPTEMBER 239 2019 REVISED: DECEMBER 30, 2019 REVISED: MAY 149 2021 TIMMONS GROUP YOUR VISION ACHIEVED THROUGH OURS. Prepared by: Jonathan Showalter, PE Timmons Group 608 Preston Avenue, Suite 200 Charlottesville, VA 22903 434.327.1681 APPROVED by the Albemarle County Datemunitv0 ev5l 1 ent Department File WP0201900054 ITIb-I\ K SHOWALTER r I.ic. No. 0402057151 �p0 05/ 13/2 1 �sS�oNAI Table of Contents Section Title Project Narrative 2.1 LD-204 Inlet Calculations 2.2 LD-229 Pipe Calculations 2.3 LD-347 Hydraulic Grade Line Analysis 2.4 LD269 Culvert Report 3 Virginia Runoff Reduction Method Worksheet Summary Project Narrative: This project included site improvements to Western Albemarle High School including a new Softball Fieldhouse, widened access road, new ADA ramp to the bus loop, and related site work. The limits of disturbance is 0.83 acres. Water Ouality The current site contains an existing field house, narrow driveway, asphalt path, and associated ramps and stairs. 0.83 acres of disturbed area was analyzed for water quality. The site will require 0.21./year to be treated. The required 0.21 lbs/yr will be satisfied by purchasing nutrient credits from a DEQ approved credit bank in accordance with LIS code of Virginia 62.1-44.15:35 Water Ouantity In the developed condition the runoff from the disturbed area will flow off as sheet flow. Level spreaders are provided at points of concentrated discharge to return runoff to sheet flow. this project fulfills the requirements of section 9VAC25-970-66 Section D. FORM LC A SHEET OF PROJECT WAHS FIeldI DMONEB: A.MABEE GATE L141=1 CHECKED: J. SHOWALTER DNGS ENGLISH mmm�mmmmo®ommmmmmmmmmmmmmmmmmmmmm�m mmm�mmm0000mmmmmmmmmmmmmmmmmmmmmm�m mmm�mmmmmmm®mmm®mmmmmmmm®mm�mmmmm�m� �m®�mmmmmmmmmmmmmmmmmmmmmmmmmmmmm�m mmm��m�mmmmmmmmmmmmmmmmmmmmmmmmmm�m mmm�mmm®o®ommmmmmmmmmmmmmmmmmmmmm�m� mmm�mmm0000mmmmmmmmmmmmmmmmmmmmmm�m mmm�mmmmmmmm®mm®mmmmmmmm®mm®mmmmm®mom �m®��mmmmmmmmmmmmmmmmmmmmmmmmmmmm�m mmm�®m�mmmmmmmmmmmmmmmmmmmmmmmmmm�m mmm�mmm®omommmmmmmmmmmmmmmmmmmmmm�m mmm�mmm0000mmmmmmmmmmmmmmmmmmmmmm�m mmm�mmmmmmm�®mm®mmmmmmmm®mmmmmmmm�m� ®�®��m�mmmmmmmmmmmmmmmmmmmmmmmmmm�m mmm�mmmomommmmmmmmmmmmmmmmmmmmmm�m mmm�mmm0000mmmmmmmmmmmmmmmmmmmmmm�m mmm�mmmmmmmm®mm®mmmmmmmm®mmmmmmmm�m� ®m®�®m®mmmmmmmmmmmmmmmmmmmmmmmmmm�m mmm�mmmomommmmmmmmmmmmmmmmmmmmmm�m mmm�mmm0000mmmmmmmmmmmmmmmmmmmmmm�m mmm�mmmmmmmm®mm®mmmmmmmm®mmmmmmmm�m� �m®��m�mmmmmmmmmmmmmmmmmmmmmmmmmm�m mmm�mmmomom®m®�o�ommmmmmmmmmmmmm�m mmm�mmm0000mmmmmmmmmmmmmmmmmmmmmm�m mmm�mmmmmmmm®mm®mmmmmmmm®mmmm�mmm�®� ��®��mmmmmmmmmmmmmmmmmmmmmmmmmmmm�m� mmm�mmmomommmmmmmmmmmmmmmmmmmmmm�m� mmm�mmm0000mmmmmmmmmmmmmmmmmmmmmm�m mmm�mmmmmmmm®mmmmmmmmmmmomm®mmmmm�m® ®m®�®m®mmmmmmmmmmmmmmmmmmmmmmmmmm�m mmm��m�mmmmmmmmmmmmmmmmmmmmmmmmmm�m mmm�mmmmomommmmmmmmmmmmmmmmmmmmmm�m mmm�mmm0000mmmmmmmmmmmmmmmmmmmmmm�m mmm�mmmmmmmm®mm®mmmmmmmm®mmmmmmmm®m® INLETSOFT BY ENSOFTEC DATE: 511C 1 LD-229 PROJECT: WAHS Reldhouse STORM SEWER DESIGN COMPUTATIONS LOCATION: COUNTY: Charlo0esNlle STORM FREQUENCY 10 NOAA STATION: Desiped by: A.MABEE Checked by: J. SHOWALTER UNITS ENGLISH PWE NO, FROMPOM TOPOWT DlA , AREA "A' Acre (3 RUNOFF COEFF. "C" 0 CA TOTAL WLET TIME M1Gnves RAW FALL WHr (8 RUNOFF INVERT ELEVATIONS LENGTH olPipe FL 12 SLOPE RJR. 13 SIZE mi. Span/Rise) la 16 SHAPE N-Ix, olPipes Opa , CFS IS Rictioa NORMAL FLOW FLOW Slope Depihol A of Hm V. Pn TRAE Flow,& FIow, Aa REMARK$ RhL FL SqF[ Ft FdS R. Sec. 16 1] 18 WCRE-ACCGM- MENT (5 ULATED 6 Ue¢ CFS Tm Q CFS (9 UPPER END (10 LOWER END 11 REFERENCE 1 STA. REFERENCH 2 STA. mi 2M 2N Ow O.W 003 5,13 6.50 &W 0.20 67492 673.61 42 0.03" 12 CirtWv 1 6.69 O.ONN 0.12 0.05 0.0 3.79 O.M 11.22 203 2N 202 007 003 0.03 003 Sql 650 &W 0.20 679.05 6T1.68 31M O.OSW3 12 CMOv 1 8.63 O.ONN 0.10 Mm 0.0 6.53 0.62 7.80 301 3M 300 065 007 0.31 031 10.W 526 &W 1.61 658Y1 656.86 31M O.WLUI 15 CMOv 1 1292 O.OWW 0.30 0.22 0.18 2.18 1.10 0.91 001 0d1 MO 058 062 0.36 053 5,10 651 &W 3.C6 667.16 66 % 53.28 O.O6W6 15 Ci . 1 1583 0.003W 0.40 0.30 0.22 1033 2.W 5.16 A03 401 A02 003 )'MI 0.12 0,17 Sql 650 &W 1.13 M8.58 M7]M 37.80 0.0M92 15 Ci . 1 1207 O.OW30 0.b 0.18 0.16 6.18 0.85 6.12 699 15M EX-1 001 0% 0.01 0,11 532 604 &W 0]6 662.D 662.01 I 25.99 0.01" 12 Ci . 1 3.86 O.O 0.30 0.20 0.12 179 0.52 6.86 501 502 5W 001 0% 0.01 0,10 SN 646 &W 0.68 662.56 662.37 VA4 Og 2 12 Ci Wv I 1M O.OW30 0.28 0.18 0.16 1.69 0.50 0.M 503 5m 5W 001 0% 0.01 0,10 5,17 609 &W 0.62 662.81 662.60 16.89 001W7 12 Ci w. 1 3.87 O.OW30 0.27 0.17 0.16 1.62 0.69 0.67 505 5W 506 001 0% 0.01 009 509 651 &W 0.56 663.08 662.91 16.89 OOIWI 12 Ci Wu 1 186 &"M O.M 0.16 0.15 1.51 0.65 0.81 5W 508 5W 022 035 0.08 008 Sql 650 &W 0.50 663.35 663.18 17.M Og 6 12 CirtWv 1 383 &"M 0.M 0.15 0.16 1.38 0.62 5.10 EXLSTlNG EX-1 EX 0,16 053 0.08 020 503 6C0 &W 1.28 661.91 65%Q 4252 0.05W3 18 CM6v 1 27,65 O.OWIO 0.M 0.16 0.16 2.96 1.20 5.M LD34T HYDRAULIC GRADE LINE ANALYSIS INCIDENCE PROBABILITY 10 Year PROJECT: WAHS Fieldhouse DESIGNED BY: Checked: A.MABEE J. SHOWALTER INLET OR JUNCTION STA. INVERT EL. OUTFLOW PIPE DEPTH OFFLOW OUTFLOW PIPE CUTLET WATER SURFACE ELEV. DIA PIPE Do INmm DESIGN DISCH. Go CFMMS LENGTH PIPE Le " FRIG➢ON SLOPE. Sb (POET) M'M FRICTION LOSS HI FIRA JUNCTION LOW SURFACE FLOW ML Hl 1S HI " InM InIH T, o1 MIA Souping? OSFINAL Water Top d lnIM PdµslmeM4 HI H Somme Elev. YM FIRA FIRA Ekw24an APPROX. Vo Cmu. He F V. Vi- 2 Hi LEW) 035'MAX. SKEW Angle K Good H FAI Sum AL FAI 1 2) 3 d 5 6 7 8 9 10 11 12 13 16 15 16 16 1718 19 200 675.750 202 673.641 1.00 675.750 12 0.196 42.54 0.00003 0.001 3.791 0.056 4.533 0.319 0.112 0.0 0.00 0.000 0.167 0.000 0.167 NO 0.167 0.169 675.919 681.460 O.K. 203 6]].681 1.00 678.481 12 0.196 35.34 0.00003 0.001 4.533 0.080 0.000 0.000 0.000 0.0 0.00 0.000 0.080 0.196 0.104 YES 0.052 0.053 679.553 682.850 O.K. d00 666.650 402 663.960 1.25 666.650 15 3.4% 53.28 0.00299 0.159 10.326 0.414 6.176 0.592 0207 0.0 0.00 0.000 0.621 2.324 0.808 YES 0.404 0.563 667.557 671.000 O.K. 404 667.260 1.25 668.260 15 1.132 37.80 0.00032 0.012 6.176 0.148 0.000 0.000 0.000 0.0 0.00 0.000 0.148 1.132 0.192 YES 0.096 0.108 668.838 671.500 O.K. PROJECT WAHS Site Improvements SHEET UNITS OF ENGLISH CULVERT DESIGNER: REVIEWER: DESIGN FORM LD-269 A. Mabee DATE: I. Showalter 9242019 ROAD COUNTY Albemarle (Zone 2) CULVERT 101 VA NOAA Station Chmlotwesille EIYDROLOGICAL DATA Method: RATIONAL Drainage Area: 0.12 Acres Timeof Concentration 5 Minutes DESIGNFLOWS Shlir. ElsF Eh= 1- S= SKEW Ek, U.= ELHWd= 667.62 0.W fl 667.84 ft 11.34 ft 3.00% Roadway Width 0 ft ROADWAY ELEVATION ft g �-------- 7 __________________________________________________ J Hwi - ---- DEPRESSION 0 u. "n''Bed 0.013 0.W ft __________ _________________________ E1o= Road Unglh 0 Freeboard= S6hlr. Eks. Rt. __. H TW DEPTH 1W TW VEL Chain 1InvE1.. 66J.50 ft Suface Type MVALIM' 0.12 0.96 667.50 PAVED ft ft ft fps ft R.I. (years) FLOW (efs) 10 Design 0.31 2 Check 0.24 10 Max. 0.31 CULVERT DESCRIPTION: TYPE: Single/Multiple Conforming Inlet Edge Description: Smeoth Tapered hdet Throat TOTAL FLOW Q cfs FLOWPER BARREL QM cfs BEADWATER CALCULATIONS CONTROL HEADWATER ELEV ft OUTLET VEL fps MLNBdI1M SHOULDER ELEV. ft COMMENTS Ill CONTROL OUTLET CONTROL Sin a/Multi le Conformin / Broken Back Call HWitD HWi ft FALL H ELHWi h TW ft do ft (dc+DM ft hn ft ke H ft ELHWO N MATERIAL SHAPE Size (in) N Mannin, Concmte Chculm 12 1 0.01 0.31 0.3 -0.22 -0.22 0.00 667.62 0.12 0.23 0.62 0.61 0.20 fi67.84 0.27 667.62 0.38 0.24 0.2 -0.24 4).24 0.00 667.60 0.10 0.20 0.60 0.60 0.20 fi67.84 0.26 667.60 0.25 0.31 0.3 -0.22 -0.22 0.00 667.62 0.12 0.23 0.62 0.61 0.20 -667.84 0.27 667.62 0.38 Broken Back Culvert TAILWATER DATA: AILWATERRESUM%O.M ROADWAY DATA: ROADWAY OVERTOPPING: LENGTH Ekv. SKEW° Shape TrepeaoWal fi- OD3$ Discharge cfs EkvaOon fl e a SF oadway Width,ft 0 Diulwge cfs OvenupTOg Dscharge Of5 Overtopping Elevation fl Daum Widdft Side Slope LL (H:1 V) Side Slope RL (HA V) Channel Slope. IM 2.50 uds-Type PAVED 2.00 66J.62 M Top OI Road Elevalion, R 0 � 0 66J.62 2.00 ck 66J.W .06 Lengto OI Road. R E Check 0 66J.60 0.0100 66J.62 .0J Max. 0 %7.62 iaanre kvadon TECHNICAL FOOTNOTES: (1) USE Q/NB FOR BOX CULVERTS (4) EILi=HWI+ELI(DNVF.RT OF INN%I CONTROL SECTION) (6)ho= TW m I&. D2)(WHICHEVER IS GREATER) (2)HWi/D= HW/D OR HWi/D FROM DESIGN CHARTS (5) TW BASED ON DOWNSTREAM CONTROL OR FLOW (7)H=[1+ke+(29oaL)/R13)s,22g (3) FALL =HWI-(ELHWd-ELsO; FALL IS ZERO FOR CULVERTS ON GRADE DEPTHINCHANNEL SUBSCRIPT DEFINITIONS: CONEU12M / DISCUSSION: CULVERT BARREL SELECTED HWd DESIGN HEADWATER t INLET SIZE: o. RNA HW IN INLET CONTROL 0 OUTLEP SHAPE: MATERIAL we HW IN OUTLET CONTROL sf Stwaul ENTRANCE @ culvert face CULVERTSOFT by ENSOFFEC, INC. PROJECT WAHS Site Improvements CULVERT DESIGN FORM LD-269 ROAD COUNTY A%e.k (Zone 2) SHEET OF DESIGNER: A. Mabee DATE: 9242019 CULVERT 101 VA UNTTS ENGLISH RE�: I. Shwa , NOAA Stnfioo Cb Ionesvi& H.W. ELEV V/S DISCHARGE OUTLET VELOCRY V/S DISCHARGE 667.6 0.4 0.4 667.E 0.3 fi67.6 _ p 0.3 &67.6 0.2 �+ 0.2 31367.6 0.1 667.E 0.1 667.6 0.0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 DISCHARGE DISCHARGE TW DEPTH V/S DISCHARGE 0.1 0.1 Z 0.1 rL 0.1 -- 0.1 0.1 _..-.._..-.._.. 0.1 0 0 0 0 0 0 0 0 DISCHARGE CULVERTSOFI by ENSOFfEC, INC. TW VELOCRY V/S DISCHARGE 1.0 1.0 1.0 0.9 0.9 O 0.9 - 0.9 0.9 0.9 - 0.9 0.9 0.9 0 0 0 0 0 0 0 0 DISCHARGE data Input cells Project Name: WAHS Site Improvements ® Dale: 5/11/2021 constant values calculation cells Linear Development Project? No Site Information Post -Development Project (Treatment Volume and Loads) Enter Total Disturbed Area (acres) 0.83 Check: BMP Desl n S ci (cations list: 2013 Draft Stds & Specs Linearproject? No r r: Land cover areas entered correctly? a '® Total disturbed area entered? Pre-ReDevelopment Land Cover (acres) A Soils BSoils7SoilsDTotals Forest/Open Space (acres) - undisturbetl 0.00 forest/open space Manned Tud(acres)-disturbed, graded for 0.65 yards or other turtto he o mwged ed/mana 0.65 Impervious Cover(aaes) 018 0.18 0.83 Post -Development Land Cover (acres) A Soils BSoils CSoils DSoils Totals Forest/Open Space (acres) -- undisturbed, 0.00 protected forest/openor refarested land s 0.00 Manned Turf (acres) disturbed, graded for D.SJ curds or other turf to be mowed/manna ed O.57 Impervious Cover (acres) 026 0.26 Area Check OK. OK. OK. OK. 0.83 Constants Runoff Coefficients Rv annual Rainfall (inches) 43 ASoils BSoils CSoils DSoils Brilliant Rainfall Event (inches) 1.00 Farest/Open Space 0.02 0.03 0.04 0.05 Wal Phosphorus (TP) EMC(ana/L) 0.26 Managec Turf 0.15 0.20 0.22 0.25 otal Nitrogen (Tell EMC(mg/L) 1.86 Impervious Cover OAS 0.95 0.95 0.95 argn TP Loatl(fiVarm/yr) 0.41 Pj(unitless correction factor) 0.90 LAND COVER SUMMARY - PRE-REDEVELOPMENTr COVER SUMMARY POST DEVELOPMENT Land Cover Summary -Pre Land Cover SummaMPost(Final) LaMCover SummaryNust IF7onalf Cover Summary -Post Pre -Re Development Listed Adjusted' Post Rates. &New Impervious Poat4leDecelapmem Port -Development New Impervious Forest/Open Space Cover (acres( 0.00 0.00 Forest/Open Space 0.00 Forest/Open Space 0.00 Cover(acres) Cover (acres) Weighted Rv(foreso 0.00 0.00 Weighted RV(mest) 0.00 Weighted Rv(forest) 0.00 %Forest 0% 0% %Forest 0% %Forest 0% Managed Turf Cover (acres) 0.65 0.57 Managed Turf Cover OSJ Managed Turf Cover 057 (acres) (acres) Weighted Rv(turf) 0.20 0.20 Weighted RV (turf) 0.20 Weighed RV (turf) 0.20 %Managed Turf 78% 76% %Manned Turf 69% %Managed Turf 76% M Cover pervious (acres) 0.18 0.18 Impervious Cover 0.26 Babes. Impervious 0.18 New Impervious Cover 0.08 (acres) Cover (acres) (acres) Rv(impervbus) 0.95 0.95 Rv(imperviaus) 0.95 Rv(impervious) 0.95 Rv(impervious) 0.95 %Iun"iaus 22% 24% %Impervious 31% %Impervious 24% Total She Areas (acres) 0.83 0.75 Final Site Area (acres) 0.83 Total Rellev. She Area 0.75 (acres) she Rv 0.36 0.38 Final Post Dev Site RV 0.43 ReDev She as 038 Treatment Volume and Nutrient Load Treatment Volume and Nutrient Load Part -Development FinalPast- Post-Rellevelopmerd Pre-ReDevelopment Treatment Volume 00251 0.0238 development 0.0301 Treabnent Vdume 0.0238 TreatmentVolume 0.0063 (acre-kl TreatmentVolume lectern) (acre-k) (acne -fit) Port -Development Final Port- Post-Reirevelopmem Pre-ReDevelopment Treatment Volume 1,093 1,035 Development 1,310 Treatment Vdume 1,035 Treatment Volume (cubic 276 (cubic feet) TreatmentVolume (cubic feet) feet) (cubicfeeu Port-0evelapmem T Pre-ReDevelopmern TP load Final Port- Post-Rellevelopmem 0.69 0.65 Development TP Load 0.82 Load ( 0.6565 0.17 (lb/yr) (Ib/yr) r (Ibty)' Load(lb/yr) pmen[lP Load For acre PmReOevelo TIF Final Part -0evelopment TP Pon-ReDevelopment lP (pment O.Ri 0.a] Load per acre 0.N Wad per acre (Ib/ave/yr) (lb/acre/yr) Baseline TP Loatl (Ib/yr) May. Reduction Required (OAl lbs/ave/yr applied to prey Nevelopment area eaduding pervious 0.31 (Below Pre, 10% land pmposetl For new impervious cover) ReDevelopment Loatl) 'Adjusted Land Cover Summary: TP Load Reduction TP Load Reduction Pre ReDevelopment land cover minus pervious land cover (rarest/open spare or Required for 0.07 , Required for New 0.14 staged turn arreogepmposediornew impervious rover. Redeveloped Area Impervious Area (Ib/yr) (lb/yr) Adjusted total orreoge is consistent with Post-ReDevelopment acreage( minus eage of new impervious cover). Column I shows food reduction requitement! for new impervious cover (based on new development bad limit, 0.41 fhs/ rroear). Post -Development TP Load Reduction Required (Ib/yrj 0.21