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Home My WebLink AboutSWA000216_Stormwater Report_20230801 • TIMMONS GROUP YOUR VISION ACHIEVED THROUGH OURS. STORMWATER REPORT CIRCLE K - EXPANSION 2723205 WINSTON-SALEM, NORTH CAROLINA PO MAY 11, 2023 PREPARED FOR: Circle K Stores Inc. 1100 Situs Court Suite 100 Raleigh, NC 27606 PREPARED BY: Timmons Group, NC License No. 023728 5410 Trinity Road, Suite 102 Raleigh, North Carolina 27607 www.tmmons.corn Circle K—Expansion 2723205 Winston-Salem, NC Project Number: 37630.142 Table of Contents Stormwater Narrative 1 Project Background 1 Proposed Project Description 1 Proposed Stormwater Management 1 Stormwater Runoff Control 1 TSS Removal 1 Seasonal High Water Table 2 Methodology for Stormwater Modeling 2 Hydrology 2 Hydraulics 2 Pre & Post Development Runoff Summary 2 Reference Material 3 NOAA Rainfall Data 3 USGS Map 3 FEMA Map 3 Soil Survey Map 3 Pre/Post Development Drainage Area Maps 3 Peak Flow Analysis 4 Worksheet— Curve Numbers 4 Hydraflow Report 4 SCM Design Calculations 5 Bioretention Worksheet 5 Outlet Protection Calculations 5 Stormwater Operation & Maintenance Agreement 5 Hydraulic Grade Line Calculations 7 Q10 Analysis Using Hydraflow Software 7 Circle K—Expansion 2723205 Winston-Salem, NC Project Number: 37630.142 Stormwater Narrative Project Background The proposed Circle K project is located at the intersection of Hickory Tree Road (SR-1508) and Old U.S. Highway 52 (SR-2932). The project site currently consists of three lots with vacant land on two lots and an existing Circle K on one lot. This project will result in one combined parcel. The total tract area of the combined lots is 1.72 acres. For reference, the subject property information is as follows: PINs: 6830-02-89-0427, 6830-02-79-7520, 6830-02-79-8499 River Basin: Yadkin Pee-Dee Classification: C Stream: Fryes Creek Total Project Site Acreage: 1.72 ac Total Disturbed Acreage: 0.95 ac Latitude & Longitude: 35°58'4"N 80°13'23"W There are 0.84 acres (48%) of existing impervious cover onsite. The site is in hydrologic soil group "B". Approximately half of the site flows away from Old U.S. Highway 52, where it is collected in a pipe system and discharges to a stormwater pond south of the site. The rest of the site drains to the west of the property. FIRM Panel 3710683000J indicates the site does not contain special flood hazard areas. No site development is proposed near a jurisdictional stream. Proposed Project Description This project proposes new high speed diesel pumps with associated parking lot, canopy, driveways and utilities. There is approximately 0.84 AC of existing impervious cover within the property boundary. The proposed improvements will result in a post-developed impervious cover of 1.10 AC (including 0.05 ac (2,178 SF) future impervious), which is approximately 67% of the total site area. Proposed Stormwater Management The proposed project consists of high-speed diesel and associated parking lot, canopy, driveways and utilities. The proposed development will increase the onsite impervious cover from 0.84 acres to 1.15 acres (66.9% of the site). Much of the onsite impervious runoff will be directed toward a proposed bioretention cell onsite. The remaining impervious area will flow offsite via a permanent diversion ditch. The bioretention cell will also discharge offsite. This design maintains the existing drainage pattern. Stormwater Runoff Control One bioretention facility is proposed to improve the quantity and quality of stormwater runoff for the site in compliance with the rules contained in the NCDEQ Stormwater Design Manual. TSS Removal The NCDEQ requirement of 85% Total Suspended Solid removal requirement has been exceeded by the proposed bioretention facility. • • If TIMMONS GROUP 1 I www.timmons.com Y___.v111 VAN _IIIL'v LV [!tHV 4[I VVIt]. Circle K—Expansion 2723205 Winston-Salem, NC Project Number: 37630.142 Seasonal High Water Table A seasonal high water table report has been requested and will be included with future submittals. Methodology for Stormwater Modeling A pre-development and post-development hydrologic analysis was completed for the site using the SCS TR20 method. A hydraulic analysis was completed using Hydraflow modeling software to route these storm events through the proposed bioretention facility and outlet structure. Hydrology The SCS TR20 method was used to determine the peak discharge rates for the pre-development and post- development conditions, develop runoff hydrographs and size the detention storage for the SCM. Rainfall data used in the design was taken from published NOAA data for the City of Winston-Salem. SCS runoff curve numbers were based on Table 2-2 in the TR55 manual. The Time of Concentration (Tc) values were determined using the TR55 method for sheet, shallow and concentrated flows, with a minimum Tc of 5 minutes. Hydraulics Computer simulated reservoir routing using Hydraflow modeling software was completed for the 1-year, 2-year, 10-year, and 100-year storm events utilizing stage-storage and stage-discharge functions. Stage-storage was determined using the proposed grading contours of the detention system and stage-discharge functions were developed using the proposed outlet structures. The outlet structures were designed to attenuate the post- development discharge rates for the 1 and 2-year events equal to or less than pre-development levels. Pre & Post Development Runoff Summary Analysis Point 1: Site Condition Storm Event (cfs) 1-year (cfs) 2-year (cfs) 10-year (cfs) 100-year (cfs) Pre-Development 0.211 0.530 1.587 3.635 Post Development 1.429 1.969 3.464 5.944 without Detention Post-Development 0.162 0.305 2.287 5.871 with Detention I• • I. TIMMONS GROUP 21 www.timmons.com Y___.v111 VAN _IIIL'v LV [!tHV 4[I VVIt]. Circle K—Expansion 2723205 Winston-Salem, NC Project Number: 37630.142 Reference Material NOAA Rainfall Data USGS Map FEMA Map Soil Survey Map Pre/Post Development Drainage Area Maps ••••s•• • TIMMONS GROUP 3 I www.timmons.com YOUR VISION ACHIEVED THROUGH OURS. 3/30/23,8:19 AM Precipitation Frequency Data Server NOAA Atlas 14,Volume 2,Version 3 es,.co Location name:Winston Salem,North Carolina, r°"""°.,,, \ USA* I none Latitude:35.968°, Longitude: -80.2232° Elevation:m/ft** '"'E$0' *source:ESRI Maps "4,,,„r. y **source:USGS POINT PRECIPITATION FREQUENCY ESTIMATES G.M.Bonnin,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)1 Average recurrence interval(years) Duration 1 2 5 10 25 50 100 200 500 1000 5-min 0.382 0.454 0.529 0.579 ' 0.634 0.669 0.699 0.723 0.747 1 0.762 (0.352-0.415) (0.418-0.494) (0.487-0.575) (0.532-0.628) (0.580-0.687) (0.608-0.726) (0.632-0.759) (0.651-0.786) (0.666-0.814) (0.673-0.832) 10-min 0.610 0.726 0.847 0.926 1.01 1.07 1.11 1.15 1.18 1.20 (0.562-0.663) (0.669-0.790) (0.779-0.921) (0.851-1.00) (0.924-1.10) (0.969-1.16) (1.00-1.21) (1.03-1.25) (1.05-1.29) (1.06-1.31) 15-min 0.762 0.912 1.07 1.17 1.28 1.35 1.40 1.45 1.49 1.51 (0.702-0.828) (0.841-0.993) (0.986-1.17) (1.08-1.27) (1.17-1.39) (1.23-1.46) (1.27-1.52) (1.30-1.57) (1.33-1.62) I (1.33-1.64) 30-min 1.05 1.26 1.52 1.70 1.90 2.03 2.15 2.25 2.37 2.44 (0.962-1.14) (1.16-1.37) (1.40-1.66) (1.56-1.84)_ (1.73-2.06) (1.85-2.20)_ (1.94-2.33) (2.03-2.45) (2.11-2.58) (2.15-2.66) 60-min 1.30 1.58 1.95 2.21 2.53 2.75 2.96 3.16 3.40 3.56 (1.20-1.42) (1.46-1.72) (1.80-2.12) (2.03-2.40)_ (2.31-2.74) (2.50-2.99) (2.68-3.22) (2.84-3.43) (3.03-3.70) (3.14-3.89) 2-hr 1.52 1.84 2.29 2.62 3.04 3.35 3.65 3.94 4.30 4.57 (1.40-1.64) (1.70-2.00) (2.11-2.48) (2.41-2.84) (2.78-3.28) (3.04-3.62) (3.29-3.95) (3.53-4.26)_ (3.81-4.67) (4.00-4.97) 3-hr 1.62 1.97 2.45 2.81 3.27 3.62 3.95 4.28 4.70 5.00 (1.50-1.76) (1.82-2.13) (2.26-2.66) (2.58-3.04) (2.99-3.53) (3.29-3.90) (3.57-4.26) (3.83-4.62) (4.15-5.09) (4.37-5.43) r - 6-hr 1.97 2.38 2.97 3.42 4.01 4.47 4.92 5.38 5.99 6.45 (1.82-2.14) (2.21-2.59) (2.74-3.23) (3.14-3.71) (3.66-4.34) (4.04-4.83) (4.42-5.32) (4.78-5.81) (5.24-6.49) , (5.58-6.99) 12-hr 2.33 2.81 3.52 4.08 4.83 5.43 6.05 6.68 7.55 8.22 (2.15-2.54) (2.59-3.08) (3.24-3.84) (3.74-4.43) (4.39-5.24) (4.89-5.87) (5.40-6.52) (5.89-7.20) (6.54-8.13) (7.00-8.86) 24-hr 2.80 3.39 4.23 4.89 5.80 6.51 7.24 8.00 9.03 9.85 (2.61-3.03) (3.15-3.65) (3.93-4.57) (4.53-5.28) (5.34-6.25) (5.99-7.03) (6.64-7.83) (7.30-8.65) (8.19-9.79) (8.89-10.7) 2-day 3.26 3.91 4.85 5.57 6.53 7.29 8.05 8.83 9.89 10.7 (3.04-3.49) (3.65-4.20) (4.52-5.21) (5.18-5.97) (6.05-7.01) (6.73-7.83) (7.41-8.66) (8.10-9.52) (9.02-10.7) (9.73-11.6) 3-day 3.45 4.14 5.11 5.87 6.88 7.68 r 8.49 9.32 10.4 11.3 (3.23-3.70) (3.88-4.44)_ (4.78-5.48) (5.47-6.28) (6.39-7.37) (7.11-8.24) (7.83-9.13) (8.56-10.0) (9.54-11.3) (10.3-12.3) 4-day 3.64 4.37 5.38 6.17 7.23 8.07 8.93 9.81 11.0 11.9 (3.42-3.90) (4.10-4.68) (5.04-5.76) (5.76-6.60) (6.73-7.74) (7.49-8.66) (8.26-9.60) (9.03-10.6) (10.1-11.9) (10.9-12.9)_ 7-day 4.17 4.98 6.04 6.89 8.03 8.93 9.85 10.8 12.1 13.1 (3.92-4.45) (4.67-5.31) (5.67-6.45) (6.45-7.35)_ (7.49-8.57) (8.30-9.54) (9.12-10.5) (9.96-11.6) (11.1-13.0) (11.9-14.1) 10-day 4.74 5.64 6.77 7.67 8.87 9.81 10.8 11.7 13.1 14.1 (4.47-5.04) (5.32-5.98) (6.38-7.18) (7.21-8.13) (8.32-9.41)j (9.17-10.4) (10.0-11.5) (10.9-12.5) (12.0-14.0) (12.9-15.1) 20-day 6.38 7.53 8.91 10.0 11.5 12.7 13.8 15.1 16.7 18.0 (6.04-6.74) (7.14-7.95) (8.44-9.41) (9.46-10.6) (10.8-12.1) (11.9-13.4) (13.0-14.7) (14.0-16.0) (15.4-17.8) (16.5-19.2) 30-day 7.90 9.30 10.8 12.0 13.5 14.7 15.8 17.0 18.5 19.7 (7.55-8.29) (8.87-9.73) (10.3-11.3) (11.4-12.5) (12.8-14.1) (13.9-15.4) (14.9-16.6) (16.0-17.9) (17.3-19.5) (18.3-20.8) 45-day 9.94 11.6 13.3 14.6 16.3 17.6 18.9 20.2 21.8 23.1 (9.52-10.4) (11.1-12.2) (12.7-13.9) (14.0-15.3) (15.6-17.1) (16.8-18.4) (17.9-19.8) (19.1-21.2) (20.5-23.0) (21.6-24.4) 60-day 11.9 13.9 15.7 17.0 18.8 20.1 21.4 22.6 24.1 25.3 (11.4-12.4) (13.3-14.5) (15.0-16.3) (16.3-17.7) (18.0-19.6) (19.2-21.0) (20.4-22.3) (21.5-23.6) (22.9-25.3) (23.9-26.6) 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 NOAAAtlas 14 document for more information. Back to Top PF graphical https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=35.9680&Ion=-80.2232&data=depth&units=english&series=pds 1/4 • f v fa , a ' y . ' �. qo t " 9QMldway ' ; oodY. iill . 119 •C. .fl,JO 1 1 ..� ° : s '�R ('/ ';•t ", \e :'!, . ,81 %r ,. his, Vi J �'. u t ; + `�v _'e7 "' _ice•- .-:<.`, --''.•„,.-,...,.,,..-, .0 y R T m6 4 ' _,_., .. .. —, v SITE AREA • o ig / 6) acro LIP - .. . — 41t)c, ' , . Q POND ffl:OFIgY *§k,.M..I,i,!• :41 T 0. 80 \. a,-lis•i,.,.,,.-t.•„„:.,,,,1-_-,0-_.i:1_0-1J,`W.1.-_-,-—1_A1,4 m-.-",,,. - 4' - .'•, .!--s-,.',.,t,,,,-„0...,-1,,._', .-, -„ <..-f%--i-_1-i,.tl•t.,'o ' WEST D '` • •t'.:_.,Ic/u,_-o_„ ELLER 4' ) xO Ca ,1 ,i t•fpiI— r National Flood Hazard Layer FIRMette :$ FEMA Legend 80°13'42"W 35°58'19"N SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT 4. I. f • llIllirIIIIIIIIrlIllr ) PI Without Base Flood Elevation(BFE) Zone A,V A99 t SPECIAL FLOOD With BFE or Depth Zone AE,AO,AH,VE,AR HAZARD AREAS Regulatory Floodway 0.2%Annual Chance Flood Hazard,Areas of 1%annual chance flood with average b '.dis - depth less than one foot or with drainage I• areas of less than one square mile zone x , . ' s • ' Future Conditions 1%Annual L s ' Chance Flood Hazard zonex 4. 1'• A Area with Reduced Flood Risk due to 111:14'11111t. 371U683100J � ' OTHER AREAS OF �" Levee.See Notes.Zonex Po �eff.�3/16/2009 4 FLOOD HAZARD Area with Flood Risk due to Leveezone D • mi... NO SCREEN Area of Minimal Flood Hazard zonex 31I Effective LOMRs N. • , OTHER AREAS Area of Undetermined Flood Hazard ZoneD • . adft GENERAL ----- Channel,Culvert,or Storm Sewer f STRUCTURES 1 1 1 1 1 1 1 Levee,Dike,or Floodwall 0 20.2 Cross Sections with Annual Chance • AREA OF MINIMAL FLOOD HAZARD - Water Surface Elevation TOWN MIDWAY a Coastal Transect 019 .Z X • ••••••••513^^^^^• Base Flood Elevation Line(BFE) •�7(]�9�*� , Limit of Study re • Jurisdiction Boundary t 1 — Coastal Transect Baseline t� OTHER _-'——'- Profile Baseline FEATURES Hydrographic Feature 11114 i .i am• .� i • Digital Data Available �' 9 N No Digital Data Available r, Ali No ? • 4 • t MAP PANELS Unmapped _ _ ii J� r • 9�, The pin displayed on the map is an approximate ;' 3710683000� - point selected by the user and does not represent eff. 3/16/2009 an authoritative property location. • • ` This map complies with FEMA's standards for the use of r ' Ilk �- digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap •4 r A0 r accuracy standards ' "', "' �� 1 WO 1 .if• 11 The flood hazard information is derived directly from the • authoritative NFHL web services provided by FEMA.This map •, _ L was exported on 3/30/2023 at 9:12 AM and does not • IR . • reflect changes or amendments subsequent to this date and .� time.The NFHL and effective information may change or • iJ + become superseded by new data over time. , 1:.. . • .' a , 7 Ail ♦T 11111111111116' tThis map image is void if the one or more of the following map ^ '.444(," ,0elements do not appear:basemap imagery,flood zone labels, legend,scale bar,map creation date,community identifiers, = FIRM panel number,and FIRM effective date.Map images for Feet 1:6 80°13'5"W 35°57'50"N unmapped and unmodernized areas cannot be used for 0 250 500 1,000 1,500 2,000 '�� regulatory purposes. Basemap:USGS National Map:Orthoimagery:Data refreshed October,2020 Custom Soil Resource Report a Map—Hydrologic Soil Group M - 56970 569650 569730 569810 569890 569970 570050 570130 570210 5/1.16110 570370 35°58'12"N p - , ,` 1 35°58'12"N ' .1\ . — T—— �PaE 41,06 PaB I • ; Ir • PaD oAd PaE _0 109). t,t, f4 - �� PaD t"‘ PaB — "PaB . � - t "PaD E X000 Gap�a� �ot�bQ daDo 7 a�aG)o��CaOQo4kifiiiii 3:; •� - ', q• 4 r :y • µkilkAi —fir . 35°57'55"N 35°57'55"N 569570 569650 569730 569810 569890 569970 570050 570130 570210 570293 568310 3 3 iN c+ M Map Scale:1:3,730 if pinted on A landscape(11"x 8.5")sheet. Meters $ N 0 50 100 200 300 A 0 150 300 600 900 Map projection:Web Mercator Corner coordinates:WG584 Feet Edge tics:UTM Zone 17N WGS84 16 Custom Soil Resource Report MAP LEGEND MAP INFORMATION Area of Interest(AOI) 0 C The soil surveys that comprise your AOI were mapped at Area of Interest(AOI) CID 1:24,000. Soils D Soil Rating Polygons Warning:Soil Map may not be valid at this scale. A 0 Not rated or not available Enlargement of maps beyond the scale of mapping can cause I Water Features A/D misunderstanding of the detail of mapping and accuracy of soil 1 Streams and Canals line placement.The maps do not show the small areas of I I B Transportation contrasting soils that could have been shown at a more detailed I B/D scale. 1-FF Rails I C ^,/ Interstate Highways C/D Please rely on the bar scale on each map sheet for map ti US Routes measurements. D Major Roads Not rated or not available Source of Map: Natural Resources Conservation Service Local Roads Web Soil Survey URL: Soil Rating Lines Background Coordinate System: Web Mercator(EPSG:3857) • Ael Aerial Photography Maps from the Web Soil Survey are based on the Web Mercator . • A/D projection,which preserves direction and shape but distorts • B distance and area.A projection that preserves area,such as the Albers equal-area conic projection,should be used if more ....we B/D accurate calculations of distance or area are required. ✓ w c This product is generated from the USDA-NRCS certified data as • r C/D of the version date(s)listed below. . r D Soil Survey Area: Davidson County,North Carolina • Not rated or not available Survey Area Data: Version 24,Sep 8,2022 Soil Rating Points A Soil map units are labeled(as space allows)for map scales 1:50,000 or larger. ▪ A/D ▪ B Date(s)aerial images were photographed: Mar 13,2022—May 9,2022 ▪ B/D 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. 17 Custom Soil Resource Report Table—Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI PaB Pacolet sandy loam,2 to B 37.2 55.6% 8 percent slopes PaD Pacolet sandy loam,8 to B 18.2 27.2% 15 percent slopes PaE Pacolet sandy loam, 15 B 11.5 17.2% to 25 percent slopes Totals for Area of Interest 66.9 100.0% Rating Options—Hydrologic Soil Group Aggregation Method: Dominant Condition Component Percent Cutoff.None Specified Tie-break Rule: Higher 18 SCS Weighted Curve Numbers-Pre-Development SSMH TOP=89786 lE IN=891.36 \ DA 1.0(TO I3MP) IEOUT=991.26 \ Category 'CN A(AO) CNi o A MONUMENT I I Woods(B Soils) 55 0.23 13 DISTURBED 1 Lawns/Managed Open Space(B Soils) 61 0.53 32 \ \0 \ I Impervious 98 0.01 1 \ r r d �, 0.77 46 4 (c,.A,) cc. TCSEGMENT 1: \ EIP 1/2"REBAR BENT v. SHEET FLOW `� o LEGEND —® 103 LF @9.5% - PART PARCEL#13-014-0-000-0006 B \ ;• N79^ N/F • a \•`- ONSITE IMPERVIOUS AREA - 52 83 TRACO 11W \ \ DB2521-640 - \ \\ - -\-\ \cy "COMMERCIAL" I,ASPHALT \ \RE u. \\ m\ \\ ROW ONSITE IMPERVIOUS �y \oe \ AREA TC SEGMENT 2: 892 \ w \ .... DRAINAGE AREA BOUNDARY SHALLOW CONCENTRATED FLOW -� �8s5,7 AL vv - - TIME OF CONCENTRATION 229 LF @6.7°/0 B \ (TC)PATH ae8 \ - ----- \ 1 V �\V v 891, _ \ v I a, \\ \ >.\ 888- v � v 886--• v v ' v _ \ ' > o NE 5/8" � I \ 1\ \ 1.; REBAR n �� —885 �� o � I 1 1 ' I _ i PART PACEL#13-014 00-0006A I DA1•0 bri...? , N/F , 1 i I\H2111H J / EIP i/2\REBAR jl !-1_, \ \ , It te la 5' Bl(T16) I HUBBARD REALTY OF WS INC ETAL I I \// 'V \,. ../ ' / _ �i I OB 1647-1156 I 1 ry ,� 1111 \ EIP 12" ¢ I (VACANT)! I 1 _ . REBAR ®/ 883' 25,789 SQ.FT. /I \ -TIlt 0.592 ACESii 11 / 1 I // / 20p 21 �� A g8_ __ -� v ABANDONEDSEPTIC 1v 1SAGOE Lo 1 47 56"W ' O. >?S. s � / rvoswei�i 5 l �5 vilk 1 1 8S v / I / wv v A �F�\ w ` gyres STUB /// g8° -. \ aONGON ACCESS,\ 7/1/ / ' \, , \ z NAL / \ \\ \ LJ -vlr e _ L�f\ ElP 12" i 8,9 ; - \� \REBAR \\ ;/ �w11 z � \ it► RIGHT-OF-WAY a v 9l 4T 56"E ' m� a m a a s q) - • - 878-- � N \ I l I \ ♦ 74,8. 1.71 REBAR \\ �\ \\ \ \ 1 j I t I \ N \ \\ �\ \ X N�0 I V v 111,2 I 1 I 'tee \g" *' \ r "' �N I 1 A � 2 _ ANALYSIS POINT#1 a Vy; r�T' I v \ \\�� v� � -3 \ \ I N Si \ N \ .4fith- 1 Iti; 1 ' N -it \I �\ A V �\ N PARCEL#13-514O-000-0006D I % ,v, I '�'!'1 2 '1 y.,/ f��® ..-. -. ... (0)VENTS "' \\ \\ \\\�una\ \ �` TAYLOR FAMILY PROPERTIES LLC I c I \ \ ^/ \ \ \ \92 C\ \ ,, is DB 1666-071 o. I 33R (VACANT) ' ` mo, 11 \\ �, DA1.1 __Al" \VA\ \\ ,sue% ' 4,so2sa.Fr. I - _ �� ; • IMPERVIOUS AREA: 0.89 AC Nh\ v,AvA\v it►r' 0.106 ACRES \ ' \ - I \I I /I I\ \\OI \\2"\ \\ \ > 1 \ IE IN=8B7 1 \ \\\ \ \ W G G 1 / \\I, 1 1\ ^ • 1 / IEOUT=BB7.4r \ \ \�\ N PART PARCEL#13-014-0-000-0006 A I n / ' /t�4 .9 \\ I CBDI /'\ 4 ,•�� \ 1 I \) \\ �\ Y�\ m sr RMw # ' TOPT-SOS3 / "`ZZZ HUBBARDRB REALTY OF W9 INC ETAL I �I W OVERG �I \ INLET=886.33 " 3 \ / '\ 11\\I \ \ \ \ N/F \ `\• OB ifid7-1156 ^ 9�4 tea'+ _ Ig 1 /E=881.56 �� a �! y / 1 ANALYSIS POINT#2 -P IEaOR �' - I‘ IN � \ EXISTING STORMWATER ' e1 \ �_ * \�R� \\\ ` \ POND I v ---_ ti"I oPM,,,, E _ _ �IB�s� V`v 1 Fs / O t zo‘ I c»NG 1 ' \ �0 / / \PART PARCEL#13-014-0-000-0006C 1 / I\ \ � \ 47 / �' /I I / � \ N/F \ EIP 12 \ REBAR / \ CIRCLE-21STORES, S 23-69 \\ / / / / / 1 I OB 2262-2132 PS \ I I \ ` ° \ \ �,: ( d / \ 44,432SQ.FT. \,__ 1 v z \ a ---_ Sad ,i,e,$,0 / NN 1.020ACRES --v ...• i 1 1. r �.� 1 - / . j8 // 1 ;Y rziw \ v �895 \ l 0 / �1 0 _ / / 1 EIP CONC / OP'P �0. �1 ` .... - MONUMENT / 1 II rSG yr I :, - EIP 1/2"_ I 89 I I LLJJ `D,SIGNAL / Pot REBAR % / ��O I O P W 0 1 / I 'g J 516NA' O 1 sicNAie / sG I/ AnL - g88 -- / - I 1 ;_ — - tO ,Y/ ' / vP/sP/su _ \ -_ 1-- ——— SIGN INe i 1 illk 37630. 142 - CIRCLE K EXPANSION 2723205 WINSTON SALEM, NC T SCALE •1"=20' •••• �1c PRE DEVELOPMENT DRAINAGE AREA MAP — April 21 , 2023 N ° z 4 TIMMONS GROUP S...3rc3a142NWc_Hi ory auss2_winamnsziemNcnWGish.m[mIA.763o.u,eioA-PREdgI Plotted on 4un023 rase An l by Alexia Pam SCS Weighted Curve Numbers-Post-Development \ DA 2.0(TO SCM) . \\l. Category •CNi A(AO) CNI x A \\ Impervious 98 0.36 35 \ Lawns/Managed Open Space(B Soils) 61 0.15 9 \ 0 0.51 44 o� .� cc_ E(G x Ad = a7 v-^-\a�_V v FAi \� `\ r-rr i DA 2.1(SCM BYPASS) BVILOIND \ \ . .0 I Category •CNi A(Ao) CNi.A � \ \ roc • ��., Impervious 98 0.01 1 _f �\ Lawns/Managed Open Spew(B Soils) 61 0.26 16 q7'E — �® PART PARCEL#13-014-0-000-0006 B \ I \ \ s� 0.27 17 N7__38' N/F • F(G%Ai) 5 TRACO-64 • C<= EA, = 62 OB 2521-640 - "COMMERCIAL" svwur I \ - - �_ �� y ��,1\ vv LEGEND -ir/ ; .qp "\\ m \ ONSITE IMPERVIOUS AREA SSS. DA2.1 - , _O �?\i„, g` °moo O\ 1 \ ROW IMPERVIOUS AREA N _ 1 .... DRAINAGE AREA BOUNDARY I _ _ _ _ �� oA� of \ �p v .;8-- I n \ TIME OF CONCENTRATION \ ,. r, % "..7. p \�, 1 (TC)PATH ° _ .. � ' w -.. — s�� — mow■ I o ° —! 1 f4j6)/ DA2.0 (TO SCM) ill i _ \,.., • 46 fill\ \ \ , \ \ 10 I fir �; g1�(11E) / 8g roll�� '' � , ... ,, � I, ...,,,..MPERVIOUS AREA: 0.33 ACRES , 40,,,4,, ki, � BIORETENTION SCM88 — \ \\ 9\ �, N � A , RIGHT-OF-WAY Ili\ / `A \, ,\V `d_._, \ \ A;A% co, _ v v I I v g V \ \ .� r�C V ` ' I ' I \ A� 87 \ �� \ \ DA2.1 I ! :! ip— ANALYSIS , 1 PPIW POINT#1 o ��` 4�'1r m\ \ , \ �"i T _-� �m v v I 1, 11 1 w°I �a -RI q� `a V A � v ��N \ I 1 \ \ 1 DA2.2 i�� 1v II I IMPERVIOUS AREA: 0.88 ACRES 4v A \I ' �; I \. \ 2,557So A\ \V A rO _ ' I I 1 I \ \ c \ /GN \ •• 1 I\ II 'I 11 1 'i \ m - 1 \ I, 1 1 \ I \ I I PART PARCEL#13-0 7 4-0-000.000HA ' n / / \\\\ 'I \ \ I, \\ \\\ NY I \\\\ I \, \ HUBBARD DB 1647-115 INC ETAL I I W' A - - it \ // ,1 \ ANALYSIS POINT#2 " '' ��`-� �� '/III EXISTING STORMWATER ` 1 \di_ /�Il,LI; ,' - - / �\�R VA \ ,1 POND \- '/// I , e•,(T, Rs ,' \` \ \ L /I � I I \` \ v'''.P \I , z %a OT__-0 ggz � Qp.bm°, , I i' I H QZ \A r m soo - cP SIGNAL vA � tii ) � °°� �/ D a� �a s� r� / .10411161101. 88g / ' I I -o / / / / vPisvisu 1 \ - -_- SIGN IHe i \ 37630. 142 - CIRCLE K EXPANSION 2723205 WINSTON SALEM, NC T SCALE1"=20' .. 1. POST DEVELOPMENT DRAINAGE AREA MAP - May 1 , 2023 1 2U 4o TIMMONS GROUP 5.3za7630 ra3 HWC_HickonTree8.52 WnelmSabnI.DWG.M1eet.hibd37630.01C3-0MPOST,ev I Plotted m 5/.0232.PM I by Alexis Foal Circle K—Expansion 2723205 Winston-Salem, NC Project Number: 37630.142 Peak Flow Analysis Worksheet — Curve Numbers Hydraflow Report �..•••• • • • TIMMONS GROUP 4 1 www.timmons.com YOUR VISION ACHIwto THROUGH OURS. TIMMONS GROUP Project: Circle K Project No.: 37630.142 Calculated By: Alexis Pocai Date: 03/29/2023 SCS Weighted Curve Numbers - Pre-Development DA 1.0 (TO BMP) Category *CN; A;(Ac) CN;x A; Woods(B Soils) 55 0.23 13 Lawns/Managed Open Space(B Soils) 61 0.53 32 Impervious 98 0.01 1 0.77 46 C�_ (C,xA') = 60 A, TIMMONS GROUP SCS Weighted Curve Numbers - Post-Development DA 2.0 (TO SCM) Category *CN; A;(Ac) CN;x A; Impervious 98 0.36 35 Lawns/Managed Open Space(B Soils) 61 0.15 9 0 0.51 44 Cc= (CI x AI) — = 87 A, DA 2.1 (SCM BYPASS) Category *CN; A;(Ac) CN;x A; Impervious 98 0.01 1 Lawns/Managed Open Space(B Soils) 61 0.26 16 0.27 17 C� (C,x A,) = 62 A, 1 Watershed Model Schematic Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 1 2 4 5 4 8 Legend Hyd. Origin Description 1 SCS Runoff DA1.0 Pre-Development 2 SCS Runoff DA2.0-Post-Development(To SCM) 3 Reservoir Bioretention 4 SCS Runoff DA2.1 -Post-Development(SCM Bypass) 5 Combine Post-Development(Detained) 8 Combine Post-Development(No Detention) Project: 2023-04-20 Biocell Routing.gpw Monday, 05/ 1 /2023 Hydraflow Table of Contents 2023-04-20 Biocell Routing.gpw Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Watershed Model Schematic 1 Hydrograph Return Period Recap 2 1 - Year Summary Report 3 Hydrograph Reports 4 Hydrograph No. 1, SCS Runoff, DA1.0 Pre-Development 4 TR-55 Tc Worksheet 5 Hydrograph No. 2, SCS Runoff, DA2.0 - Post-Development (To SCM). 6 Hydrograph No. 3, Reservoir, Bioretention 7 Pond Report - Bioretention 8 Hydrograph No. 4, SCS Runoff, DA2.1 - Post-Development (SCM Bypass) 9 Hydrograph No. 5, Combine, Post-Development (Detained) 10 Hydrograph No. 8, Combine, Post-Development (No Detention) 11 2 - Year Summary Report 12 Hydrograph Reports 13 Hydrograph No. 1, SCS Runoff, DA1.0 Pre-Development 13 Hydrograph No. 2, SCS Runoff, DA2.0 - Post-Development (To SCM). 14 Hydrograph No. 3, Reservoir, Bioretention 15 Hydrograph No. 4, SCS Runoff, DA2.1 - Post-Development (SCM Bypass) 16 Hydrograph No. 5, Combine, Post-Development (Detained) 17 Hydrograph No. 8, Combine, Post-Development (No Detention) 18 10 - Year Summary Report 19 Hydrograph Reports 20 Hydrograph No. 1, SCS Runoff, DA1.0 Pre-Development 20 Hydrograph No. 2, SCS Runoff, DA2.0 - Post-Development (To SCM). 21 Hydrograph No. 3, Reservoir, Bioretention 22 Hydrograph No. 4, SCS Runoff, DA2.1 - Post-Development (SCM Bypass) 23 Hydrograph No. 5, Combine, Post-Development (Detained) 24 Hydrograph No. 8, Combine, Post-Development (No Detention) 25 100 - Year Summary Report 26 Hydrograph Reports 27 Hydrograph No. 1, SCS Runoff, DA1.0 Pre-Development 27 Hydrograph No. 2, SCS Runoff, DA2.0 - Post-Development (To SCM). 28 Hydrograph No. 3, Reservoir, Bioretention 29 Hydrograph No. 4, SCS Runoff, DA2.1 - Post-Development (SCM Bypass) 30 Hydrograph No. 5, Combine, Post-Development (Detained) 31 Hydrograph No. 8, Combine, Post-Development (No Detention) 32 IDF Report 33 2 Hydrograph Return Period RecaD draflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Hyd. Hydrograph Inflow Peak Outflow(cfs) Hydrograph No. type hyd(s) Description (origin) 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr 1 SCS Runoff 0.211 0.530 1.587 2.338 3.635 DA1.0 Pre-Development 2 SCS Runoff 1.339 1.767 2.871 3.540 4.594 DA2.0-Post-Development(To SCM) 3 Reservoir 2 0.077 0.086 1.782 3.325 4.505 Bioretention 4 SCS Runoff 0.107 0.231 0.623 0.897 1.366 DA2.1 -Post-Development(SCM Byp 5 Combine 3,4 0.162 0.305 2.287 4.222 5.871 Post-Development(Detained) 8 Combine 2,4, 1.429 1.969 3.464 4.411 5.944 Post-Development(No Detention) Proj. file: 2023-04-20 Biocell Routing.gpw Monday, 05/ 1 /2023 3 Hydrograph Summary Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph No. type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cuft) (ft) (cuft) 1 SCS Runoff 0.211 2 720 693 DA1.0 Pre-Development 2 SCS Runoff 1.339 2 716 2,717 DA2.0-Post-Development(To SCM) 3 Reservoir 0.077 2 772 2,699 2 885.96 1,443 Bioretention 4 SCS Runoff 0.107 2 718 296 DA2.1 -Post-Development(SCM Byp 5 Combine 0.162 2 720 2,994 3,4 Post-Development(Detained) 8 Combine 1.429 2 718 3,013 2,4, Post-Development(No Detention) 2023-04-20 Biocell Routing.gpw Return Period: 1 Year Monday, 05/ 1 /2023 4 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 1 DA1.0 Pre-Development Hydrograph type = SCS Runoff Peak discharge = 0.211 cfs Storm frequency = 1 yrs Time to peak = 720 min Time interval = 2 min Hyd. volume = 693 cuft Drainage area = 0.770 ac Curve number = 60 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 6.40 min Total precip. = 2.80 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 DA1.0 Pre-Development Q (cfs) Hyd. No. 1 -- 1 Year Q (cfs) 0.50 0.50 0.45 0.45 0.40 0.40 0.35 0.35 0.30 0.30 0.25 0.25 0.20 0.20 0.15 0.15 0.10 0.10 0.05 0.05 0.00 — - 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 1 Time (min) 5 TR55 Tc Worksheet Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Hyd. No. 1 DA1.0 Pre-Development Description A B C Totals Sheet Flow Manning's n-value = 0.150 0.011 0.011 Flow length (ft) = 100.0 0.0 0.0 Two-year 24-hr precip. (in) = 3.46 0.00 0.00 Land slope (%) = 8.00 0.00 0.00 Travel Time (min) = 5.41 + 0.00 + 0.00 = 5.41 Shallow Concentrated Flow Flow length (ft) = 230.00 0.00 0.00 Watercourse slope (%) = 6.00 0.00 0.00 Surface description = Unpaved Paved Paved Average velocity (ft/s) =3.95 0.00 0.00 Travel Time (min) = 0.97 + 0.00 + 0.00 = 0.97 Channel Flow X sectional flow area (sqft) = 0.00 0.00 0.00 Wetted perimeter(ft) = 0.00 0.00 0.00 Channel slope (%) = 0.00 0.00 0.00 Manning's n-value = 0.015 0.015 0.015 Velocity (ft/s) =0.00 0.00 0.00 Flow length (ft) ({0})0.0 0.0 0.0 Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00 Total Travel Time, Tc 6.40 min 6 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 2 DA2.0 - Post-Development (To SCM) Hydrograph type = SCS Runoff Peak discharge = 1.339 cfs Storm frequency = 1 yrs Time to peak = 716 min Time interval = 2 min Hyd. volume = 2,717 cuft Drainage area = 0.510 ac Curve number = 87 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 2.80 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 DA2.0 - Post-Development (To SCM) Q (cfs) Hyd. No. 2 -- 1 Year Q (cfs) 2.00 - 2.00 1.00 - 1.00 0.00 - 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Hyd No. 2 Time (min) 7 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 3 Bioretention Hydrograph type = Reservoir Peak discharge = 0.077 cfs Storm frequency = 1 yrs Time to peak = 772 min Time interval = 2 min Hyd. volume = 2,699 cuft Inflow hyd. No. = 2 - DA2.0 - Post-Development I(VFaxSElMation = 885.96 ft Reservoir name = Bioretention Max. Storage = 1,443 cuft Storage Indication method used. Outflow includes exfiltration. Bioretention Q (cfs) Hyd. No. 3 -- 1 Year Q (cfs) 2.00 - 2.00 1.00 - 1.00 0.00 - - 0.00 0 240 480 720 960 1200 1440 1680 1920 2160 2400 2640 Time (min) Hyd No. 3 Hyd No. 2 111111111 Total storage used = 1,443 cuft Pond Report 8 Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Pond No. 1 - Bioretention Pond Data Contours-User-defined contour areas.Average end area method used for volume calculation.Begining Elevation=885.00 ft Stage/Storage Table Stage(ft) Elevation(ft) Contour area(sqft) Incr.Storage(cuft) Total storage(cuft) 0.00 885.00 1,280 0 0 1.00 886.00 1,724 1,502 1,502 1.50 886.50 1,967 923 2,425 2.00 887.00 2,224 1,048 3,473 3.00 888.00 2,747 2,486 5,958 Culvert/Orifice Structures Weir Structures [A] [B] [C] [PrfRsr] [A] [B] [C] [0] Rise(in) = 18.00 0.00 0.00 0.00 Crest Len(ft) = 16.00 20.00 0.00 0.00 Span(in) = 18.00 0.00 0.00 0.00 Crest El.(ft) = 886.50 887.00 0.00 0.00 No.Barrels = 1 0 0 0 Weir Coeff. = 3.33 3.33 3.33 3.33 Invert El.(ft) = 880.00 0.00 0.00 0.00 Weir Type = 1 Rect --- --- Length(ft) = 50.00 0.00 0.00 0.00 Multi-Stage = Yes No No No Slope(%) = 1.00 0.00 0.00 n/a N-Value = .013 .013 .013 n/a Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(in/hr) = 2.000(by Contour) Multi-Stage = n/a No No No 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(ft) Stage I Discharge Elev(ft) 3.00 - 888.00 2.00 887.00 1.00 886.00 0.00 885.00 0.00 9.00 18.00 27.00 36.00 45.00 54.00 63.00 72.00 81.00 90.00 Total Q Discharge(cfs) 9 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 4 DA2.1 - Post-Development (SCM Bypass) Hydrograph type = SCS Runoff Peak discharge = 0.107 cfs Storm frequency = 1 yrs Time to peak = 718 min Time interval = 2 min Hyd. volume = 296 cuft Drainage area = 0.270 ac Curve number = 62 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 2.80 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 DA2.1 - Post-Development (SCM Bypass) Q (cfs) Hyd. No. 4 -- 1 Year Q (cfs) 0.50 0.50 0.45 0.45 0.40 0.40 0.35 0.35 0.30 0.30 0.25 0.25 0.20 0.20 0.15 0.15 0.10 0.10 0.05 0.05 0.00 - 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 4 Time (min) 10 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 5 Post-Development (Detained) Hydrograph type = Combine Peak discharge = 0.162 cfs Storm frequency = 1 yrs Time to peak = 720 min Time interval = 2 min Hyd. volume = 2,994 cuft Inflow hyds. = 3, 4 Contrib. drain. area = 0.270 ac Post-Development (Detained) Q (cfs) Hyd. No. 5-- 1 Year Q (cfs) 0.50 0.50 0.45 0.45 0.40 0.40 0.35 0.35 0.30 0.30 0.25 0.25 0.20 0.20 0.15 0.15 0.10 0.10 0.05 0.05 0.00 ]LiF11111111111.111111" 0.00 0 240 480 720 960 1200 1440 1680 1920 2160 2400 Time (min) Hyd No. 5 Hyd No. 3 Hyd No. 4 11 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 8 Post-Development (No Detention) Hydrograph type = Combine Peak discharge = 1.429 cfs Storm frequency = 1 yrs Time to peak = 718 min Time interval = 2 min Hyd. volume = 3,013 cuft Inflow hyds. = 2, 4 Contrib. drain. area = 0.780 ac Post-Development (No Detention) Q (cfs) Hyd. No. 8 -- 1 Year Q (cfs) 2.00 2.00 1.00 - 1.00 0.00 � 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Time (min) Hyd No. 8 Hyd No. 2 Hyd No. 4 12 Hydrograph Summary Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph No. type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cuft) (ft) (cuft) 1 SCS Runoff 0.530 2 718 1,270 DA1.0 Pre-Development 2 SCS Runoff 1.767 2 716 3,617 DA2.0-Post-Development(To SCM) 3 Reservoir 0.086 2 782 3,598 2 886.27 2,004 Bioretention 4 SCS Runoff 0.231 2 718 519 DA2.1 -Post-Development(SCM Byp 5 Combine 0.305 2 718 4,117 3,4 Post-Development(Detained) 8 Combine 1.969 2 716 4,136 2,4, Post-Development(No Detention) 2023-04-20 Biocell Routing.gpw Return Period: 2 Year Monday, 05/ 1 /2023 13 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 1 DA1.0 Pre-Development Hydrograph type = SCS Runoff Peak discharge = 0.530 cfs Storm frequency = 2 yrs Time to peak = 718 min Time interval = 2 min Hyd. volume = 1,270 cuft Drainage area = 0.770 ac Curve number = 60 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 6.40 min Total precip. = 3.39 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 DA1.0 Pre-Development Q (cfs) Hyd. No. 1 -- 2 Year Q(cfs) 1.00 - 1.00 0.90 0.90 0.80 0.80 0.70 0.70 0.60 0.60 0.50 0.50 0.40 0.40 0.30 0.30 0.20 0.20 0.10 0.10 0.00 - A 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 1 Time (min) 14 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 2 DA2.0 - Post-Development (To SCM) Hydrograph type = SCS Runoff Peak discharge = 1.767 cfs Storm frequency = 2 yrs Time to peak = 716 min Time interval = 2 min Hyd. volume = 3,617 cuft Drainage area = 0.510 ac Curve number = 87 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 3.39 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 DA2.0 - Post-Development (To SCM) Q (cfs) Hyd. No. 2 -- 2 Year Q (cfs) 2.00 - 2.00 1.00 - 1.00 0.00 - ' 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 Hyd No. 2 Time (min) 15 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 3 Bioretention Hydrograph type = Reservoir Peak discharge = 0.086 cfs Storm frequency = 2 yrs Time to peak = 782 min Time interval = 2 min Hyd. volume = 3,598 cuft Inflow hyd. No. = 2 - DA2.0 - Post-Development I(VFaxSEll ation = 886.27 ft Reservoir name = Bioretention Max. Storage = 2,004 cuft Storage Indication method used. Outflow includes exfiltration. Bioretention Q (cfs) Hyd. No. 3 -- 2 Year Q (cfs) 2.00 2.00 1.00 - 1.00 0.00 - 0.00 0 240 480 720 960 1200 1440 1680 1920 2160 2400 2640 Time (min) Hyd No. 3 Hyd No. 2 111111111 Total storage used = 2,004 cuft 16 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 4 DA2.1 - Post-Development (SCM Bypass) Hydrograph type = SCS Runoff Peak discharge = 0.231 cfs Storm frequency = 2 yrs Time to peak = 718 min Time interval = 2 min Hyd. volume = 519 cuft Drainage area = 0.270 ac Curve number = 62 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 3.39 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 DA2.1 - Post-Development (SCM Bypass) Q (cfs) Hyd. No. 4 -- 2 Year Q (cfs) 0.50 0.50 0.45 0.45 0.40 0.40 0.35 0.35 0.30 0.30 0.25 0.25 0.20 0.20 0.15 0.15 0.10 0.10 ::: t 0.05 — J ' 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 4 Time (min) 17 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 5 Post-Development (Detained) Hydrograph type = Combine Peak discharge = 0.305 cfs Storm frequency = 2 yrs Time to peak = 718 min Time interval = 2 min Hyd. volume = 4,117 cuft Inflow hyds. = 3, 4 Contrib. drain. area = 0.270 ac Post-Development (Detained) Q (cfs) Hyd. No. 5-- 2 Year Q (cfs) 0.50 0.50 0.45 0.45 0.40 0.40 0.35 0.35 0.30 0.30 0.25 0.25 0.20 0.20 0.15 0.15 0.10 0.10 0.05 — - 0.05 0.00 0.00 0 240 480 720 960 1200 1440 1680 1920 2160 2400 Time (min) Hyd No. 5 Hyd No. 3 Hyd No. 4 18 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 8 Post-Development (No Detention) Hydrograph type = Combine Peak discharge = 1.969 cfs Storm frequency = 2 yrs Time to peak = 716 min Time interval = 2 min Hyd. volume = 4,136 cuft Inflow hyds. = 2, 4 Contrib. drain. area = 0.780 ac Post-Development (No Detention) Q (cfs) Hyd. No. 8 -- 2 Year Q (cfs) 2.00 2.00 1.00 - 1.00 1\ 111111 0.00 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Time (min) Hyd No. 8 Hyd No. 2 Hyd No. 4 19 Hydrograph Summary Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph No. type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cuft) (ft) (cuft) 1 SCS Runoff 1.587 2 718 3,242 DA1.0 Pre-Development 2 SCS Runoff 2.871 2 716 6,012 DA2.0-Post-Development(To SCM) 3 Reservoir 1.782 2 722 5,993 2 886.60 2,635 Bioretention 4 SCS Runoff 0.623 2 718 1,260 DA2.1 -Post-Development(SCM Byp 5 Combine 2.287 2 720 7,253 3,4 Post-Development(Detained) 8 Combine 3.464 2 716 7,271 2,4, Post-Development(No Detention) 2023-04-20 Biocell Routing.gpw Return Period: 10 Year Monday, 05/ 1 /2023 20 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 1 DA1.0 Pre-Development Hydrograph type = SCS Runoff Peak discharge = 1.587 cfs Storm frequency = 10 yrs Time to peak = 718 min Time interval = 2 min Hyd. volume = 3,242 cuft Drainage area = 0.770 ac Curve number = 60 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 6.40 min Total precip. = 4.89 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 DA1.0 Pre-Development Q (cfs) Hyd. No. 1 -- 10 Year Q (cfs) 2.00 - i 2.00 • 1.00 - l • 1.00 • 0.00 ' 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 1 Time (min) 21 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 2 DA2.0 - Post-Development (To SCM) Hydrograph type = SCS Runoff Peak discharge = 2.871 cfs Storm frequency = 10 yrs Time to peak = 716 min Time interval = 2 min Hyd. volume = 6,012 cuft Drainage area = 0.510 ac Curve number = 87 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 4.89 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 DA2.0 - Post-Development (To SCM) Q (cfs) Hyd. No. 2 -- 10 Year Q (cfs) 3.00 3.00 2.00 2.00 1.00 1.00 0.00 — 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 Hyd No. 2 Time (min) 22 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 3 Bioretention Hydrograph type = Reservoir Peak discharge = 1.782 cfs Storm frequency = 10 yrs Time to peak = 722 min Time interval = 2 min Hyd. volume = 5,993 cuft Inflow hyd. No. = 2 - DA2.0 - Post-Development kVFaxSE1M ation = 886.60 ft Reservoir name = Bioretention Max. Storage = 2,635 cuft Storage Indication method used. Outflow includes exfiltration. Bioretention Q (cfs) Hyd. No. 3 -- 10 Year Q (cfs) 3.00 3.00 2.00 2.00 1.00 1.00 0.00 ' 0.00 0 240 480 720 960 1200 1440 1680 1920 Time (min) Hyd No. 3 Hyd No. 2 111111111 Total storage used = 2,635 cuft 23 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 4 DA2.1 - Post-Development (SCM Bypass) Hydrograph type = SCS Runoff Peak discharge = 0.623 cfs Storm frequency = 10 yrs Time to peak = 718 min Time interval = 2 min Hyd. volume = 1,260 cuft Drainage area = 0.270 ac Curve number = 62 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 4.89 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 DA2.1 - Post-Development (SCM Bypass) Q (cfs) Hyd. No. 4 -- 10 Year Q(cfs) 1.00 - 1.00 0.90 0.90 0.80 0.80 0.70 0.70 0.60 0.60 0.50 0.50 0.40 0.40 0.30 0.30 0.20 0.20 0.10 0.10 0.00 J 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 4 Time (min) 24 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 5 Post-Development (Detained) Hydrograph type = Combine Peak discharge = 2.287 cfs Storm frequency = 10 yrs Time to peak = 720 min Time interval = 2 min Hyd. volume = 7,253 cuft Inflow hyds. = 3, 4 Contrib. drain. area = 0.270 ac Post-Development (Detained) Q (cfs) Hyd. No. 5-- 10 Year Q (cfs) 3.00 3.00 2.00 2.00 1.00 1.00 0.00 - -. 0.00 0 240 480 720 960 1200 1440 1680 1920 Time (min) Hyd No. 5 Hyd No. 3 Hyd No. 4 25 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 8 Post-Development (No Detention) Hydrograph type = Combine Peak discharge = 3.464 cfs Storm frequency = 10 yrs Time to peak = 716 min Time interval = 2 min Hyd. volume = 7,271 cuft Inflow hyds. = 2, 4 Contrib. drain. area = 0.780 ac Post-Development (No Detention) Q (cfs) Hyd. No. 8 -- 10 Year Q (cfs) 4.00 4.00 3.00 3.00 2.00 2.00 1.00 1.00 0.00 — 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Time (min) — Hyd No. 8 Hyd No. 2 Hyd No. 4 26 Hydrograph Summary Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph No. type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cuft) (ft) (cuft) 1 SCS Runoff 3.635 2 718 7,271 DA1.0 Pre-Development 2 SCS Runoff 4.594 2 716 9,913 DA2.0-Post-Development(To SCM) 3 Reservoir 4.505 2 718 9,894 2 886.69 2,822 Bioretention 4 SCS Runoff 1.366 2 718 2,737 DA2.1 -Post-Development(SCM Byp 5 Combine 5.871 2 718 12,631 3,4 Post-Development(Detained) 8 Combine 5.944 2 716 12,650 2,4, Post-Development(No Detention) 2023-04-20 Biocell Routing.gpw Return Period: 100 Year Monday, 05/ 1 /2023 27 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 1 DA1.0 Pre-Development Hydrograph type = SCS Runoff Peak discharge = 3.635 cfs Storm frequency = 100 yrs Time to peak = 718 min Time interval = 2 min Hyd. volume = 7,271 cuft Drainage area = 0.770 ac Curve number = 60 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 6.40 min Total precip. = 7.24 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 DA1.0 Pre-Development Q (cfs) Hyd. No. 1 -- 100 Year Q (cfs) 4.00 4.00 3.00 3.00 2.00 2.00 1.00 1.00 0.00 _ - 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Time (min) — Hyd No. 1 28 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 2 DA2.0 - Post-Development (To SCM) Hydrograph type = SCS Runoff Peak discharge = 4.594 cfs Storm frequency = 100 yrs Time to peak = 716 min Time interval = 2 min Hyd. volume = 9,913 cuft Drainage area = 0.510 ac Curve number = 87 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 7.24 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 DA2.0 - Post-Development (To SCM) Q (cfs) Hyd. No. 2 -- 100 Year Q(cfs) 5.00 5.00 4.00 4.00 3.00 3.00 2.00 2.00 1.00 "'"'°°.'*....--.' 1.00 0.00 0.00 0 120 240 360 480 600 720 840 960 1080 1200 Hyd No. 2 Time (min) 29 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 3 Bioretention Hydrograph type = Reservoir Peak discharge = 4.505 cfs Storm frequency = 100 yrs Time to peak = 718 min Time interval = 2 min Hyd. volume = 9,894 cuft Inflow hyd. No. = 2 - DA2.0 - Post-Development KM<SEltiNation = 886.69 ft Reservoir name = Bioretention Max. Storage = 2,822 cuft Storage Indication method used. Outflow includes exfiltration. Bioretention Q (cfs) Hyd. No. 3 -- 100 Year Q (cfs) 5.00 5.00 4.00 4.00 3.00 3.00 2.00 2.00 1.00 1.00 0.00 —' I 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 1680 Time (min) — Hyd No. 3 Hyd No. 2 TTTTTT II Total storage used = 2,822 cuft 30 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 4 DA2.1 - Post-Development (SCM Bypass) Hydrograph type = SCS Runoff Peak discharge = 1.366 cfs Storm frequency = 100 yrs Time to peak = 718 min Time interval = 2 min Hyd. volume = 2,737 cuft Drainage area = 0.270 ac Curve number = 62 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 7.24 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 DA2.1 - Post-Development (SCM Bypass) Q (cfs) Hyd. No. 4 -- 100 Year Q (cfs) 2.00 - 2.00 1.00 - 1.00 0.00 - 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 4 Time (min) 31 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 5 Post-Development (Detained) Hydrograph type = Combine Peak discharge = 5.871 cfs Storm frequency = 100 yrs Time to peak = 718 min Time interval = 2 min Hyd. volume = 12,631 cuft Inflow hyds. = 3, 4 Contrib. drain. area = 0.270 ac Post-Development (Detained) Q (cfs) Hyd. No. 5 -- 100 Year Q(cfs) 6.00 I 6.00 5.00 5.00 4.00 4.00 3.00 3.00 2.00 2.00 1.00 1.00 0.00 - - - �L ' 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Time (min) Hyd No. 5 Hyd No. 3 Hyd No. 4 32 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Hyd. No. 8 Post-Development (No Detention) Hydrograph type = Combine Peak discharge = 5.944 cfs Storm frequency = 100 yrs Time to peak = 716 min Time interval = 2 min Hyd. volume = 12,650 cuft Inflow hyds. = 2, 4 Contrib. drain. area = 0.780 ac Post-Development (No Detention) Q (cfs) Hyd. No. 8 -- 100 Year Q(cfs) 6.00 6.00 5.00 5.00 4.00 M 4.00 3.00 3.00 2.00 2.00 1.00 1.00 0.00 - �� 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 Time (min) Hyd No. 8 Hyd No. 2 Hyd No. 4 33 Hydraflow Rainfall Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2023 Monday,05/1 /2023 Return Intensity-Duration-Frequency Equation Coefficients(FHA) Period (Yrs) B D E (N/A) 1 60.0390 12.8000 0.8939 2 68.4261 12.8000 0.8789 3 0.0000 0.0000 0.0000 5 69.1848 12.6000 0.8329 10 70.4909 12.6000 0.8081 25 57.4969 10.8000 0.7332 50 53.2976 10.1000 0.6975 100 47.9028 9.2000 0.6571 File name:Winston-Salem(South),IDF Intensity= B/(Tc+ D)^E Return Intensity Values(in/hr) Period (Yrs) 5 min 10 15 20 25 30 35 40 45 50 55 60 1 4.58 3.67 3.07 2.65 2.34 2.09 1.89 1.73 1.60 1.48 1.39 1.30 2 5.45 4.38 3.68 3.18 2.81 2.52 2.29 2.10 1.94 1.80 1.68 1.58 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5 6.35 5.15 4.36 3.80 3.37 3.04 2.77 2.55 2.36 2.21 2.07 1.95 10 6.95 5.67 4.83 4.22 3.76 3.40 3.11 2.87 2.66 2.49 2.34 2.21 25 7.60 6.21 5.30 4.66 4.17 3.79 3.48 3.23 3.01 2.83 2.67 2.53 50 8.02 6.57 5.63 4.96 4.46 4.06 3.74 3.48 3.25 3.06 2.90 2.75 100 8.38 6.87 5.90 5.22 4.70 4.30 3.97 3.70 3.48 3.28 3.11 2.96 Tc=time in minutes.Values may exceed 60. Precip.file name:K:\300\332-Raleigh Commercial\Reference\HYDRAFLOW\Rainfall Data\DURHAM.pcp Rainfall Precipitation Table (in) Storm Distribution 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr SCS 24-hour 2.80 3.39 0.00 4.40 4.89 5.80 6.70 7.24 SCS 6-Hr 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-1st 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-2nd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-3rd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-4th 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-Indy 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Custom 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Circle K—Expansion 2723205 Winston-Salem, NC Project Number: 37630.142 SCM Design Calculations Bioretention Worksheet Outlet Protection Calculations Stormwater Supplement Forms .•••s•• • TIMMONS GROUP 5 1 www.timmons.com YOUR VISION ACHIEVED THROUGH OURS. BIORETENTION NAME .•••••� PROJECT NAME BIORETENTION . O. Circle K-Winston Salem CALCULATED BY TIMMONS GROUP PROJECT NUMBER Alexis Pocai "" 37630.142 BIORETENTION CELL CALCULATIONS BIORETENTION NAME: BIORETENTION SITE INFORMATION NOTES&FORMULAS Drainage Area(A)= 0.49 Acres (Drainage Area to Bioretention-Including Bioretention) Impervious Area= 0.35 Acres Includes.03 ac future impervious Percent Impervious= 71.43 REQUIRED WATER QUALITY VOLUME WO,=(PI(I,)(A) 12 Design Storm(P)= 1.00 inch where: Rv Value(Rv) 0.69 WO, =water quality volume in ac-ft P =1 inch of rainfall Drainage Area(A)= 0.49 Acres R, =0.05+0.009(1),where 1=the percent impervious cover A =drainage area in acres Water Quality Volume= 0.03 Ac-ft Required Water Quality Volume= [ 1232 Cu-ft (Required Storage Volume for Water Quality) PROVIDED WATER QUALITY VOLUME Elevation Contour Area(sf) Depth(ft) Incremental Volume Cumulative Volume Elevation Notes 885.00 1280 0.00 0 0 (Bottom Elevation/Planted Surface Elevation) 886.00 1724 1.00 1502 1502 (Design Water Quality Surface Elevation) 886.50 1967 1.50 923 2425 (Peak Attenuation Outlet Elevation) 887.00 2224 2.00 1048 3473 (Peak Attenuation Volume Surface Elevation) Required Water Quality Volume= 1232 Cu-ft Provided Water Quality Volume= 1502 Cu-ft OK-1 Maximum Ponding Depth for Water 12 Inches Provided Ponding Depth for Water 12.00 Inches OK Quality Volume Quality Volume Maximum Ponding Depth for Peak 18 Inches Provided Ponding Depth for Peak 18.00 Inches i OK Attenuation Outlet Elevation Attenuation Outlet Elevation Maximum Ponding Depth for Peak 24 Inches Provided Ponding Depth for Peak 24.00 Inches OK Attenuation Volume(DepthATT) Attenuation Volume MEDIA DEPTH AND ELEVATION Bioretention Cells Design Criteria In-Situ Soils Infiltration Rate N/A in/hr (Obtained from Geotechnical Evaluation) Select Planting Type Grass/Herbaceous Plants with Underdrains (Option without Underdrains is only allowed if In- Select Top Vegetation Vegetated with Grass Situ Soils Infiltration Rate from Geotechnical Required Media Depth= 30 inches Evaluation is 2 in/hr or greater) Bottom of Media Elevation= 882.50 ft (2-4"Mulch Req.if not vegetated with grass) DRAWDOWN TIME I UNDERDRAIN SIZING Soil Media Infiltration Rate(Ir)= 2.00 in/hr 4.63E-05 ft/s (Minimum infiltration rate must be 1 in/hr) Underdrain Flow(F)= 0.08 cfs Flow=(Ir*WQ Surface Area) Factor of Safety(FS=10) 10.00 cfs (Factor of Safety should be 2-10) Underdrain Design Flow(Q)= 0.80 cfs (Design Flow=F*FS) Underdrain Pipe Slope(S)= 0.50% (0.5%is recommended) Diameter of Single Pipe(D)= 3.09 inches (D=16*[(Q*0.011)/(S^0.5)]^3/8) Underdrain Pipe Size= 4 inches (Recommend 4"or 6"pipes,OK) Number of 4"Pipes= 2 (Derived from NCDEQ SW Design Maunal A-5) Number of Cleanouts= 1.724 (Cleanout Required for every 1000 SF of SA) 2"Washed Sand Bottom Elevation= 882.33 ft Install Filter Fabric @ this Elevation (Media Bottom-2"Washed Sand-2"#89 Washed Choking Stone-2"Washed#57 Stone-Underdrain Underdrain Invert Elevation= 881.67 ft Diameter) Bottom of Bioretention Cell= 881.50 ft (Underdrain Invert-2"Washed#57 Stone) Seasonal High Water Table Elev.= TBD ft Verify Seasonal High Water Table SHWT>2'below bottom TBD from Geotechnical Report LATEST REVISION:5/2/2023 10:33 AM ifiv I*a' PROJECT NAME Circle K- Expansion 2723205 CALCULATED BY T I M M O N S GROUP PROJECT NUMBER April Blye ENGINEERING I DESIGN TECHNOLO= 37630.142 Pipe Outlet Protection (NYDOT Method) Structure Name: FES100 Pipe Diameter= 15 in From Fig. 8.06.c: ZONE = 2 Pipe Slope = 0.025 ft/ft Mannings n = 0.013 Rip Rap Class= B Velocity Flowing Full = 8.35 fps Apron Thickness= 18 in Apron Length = 7.5 ft Apron Width = 3xDia.= 3.8 ft From Fig. 8.06.e: Length Structure Name: FES102 Pipe Diameter= 15 in From Fig. 8.06.c: ZONE = 1 Pipe Slope= 0.01 ft/ft Mannings n = 0.013 Rip Rap Class= A Velocity Flowing Full = 5.28 fps Apron Thickness= 12 in Apron Length = 5.0 ft Apron Width = 3xDia.= 3.8 ft From Fig. 8.06.e: Length LATEST REVISION:5/2/2023 10:26 AM SUPPLEMENT-EZ COVER PAGE FORMS LOADED PROJECT INFORMATION 1 Project Name CIRCLE K-EXPANSION 2723205 -WINSTON SALEM,NC 2 Project Area(ac) 1.72 3 Coastal Wetland Area(ac) N/A 4 Surface Water Area(ac) N/A 5 Is this project High or Low Density? High 6 Does this project use an off-site SCM? No COMPLIANCE WITH 02H.1003(4) 7 Width of vegetated setbacks provided(feet) 0 8 Will the vegetated setback remain vegetated? N/A 9 If BUA is proposed in the setback,does it meet NCAC 02H.1003(4)(c-d)? N/A 10 Is streambank stabilization proposed on this project? No NUMBER AND TYPE OF SCMs: 11 Infiltration System 12 Bioretention Cell 1 13 Wet Pond 14 Stormwater Wetland 15 Permeable Pavement 16 Sand Filter 17 Rainwater Harvesting(RWH) 18 Green Roof 19 Level Spreader-Filter Strip(LS-FS) 20 Disconnected Impervious Surface(DIS) 21 Treatment Swale 22 Dry Pond 23 StormFilter 24 Silva Cell 25 Bayfilter 26 Filterra FORMS LOADED DESIGNER CERTIFICATION 27 Name and Title: Jacob Dooley 28 Organization: Timmons Group 29 Street address: 5410 Trinity Rd Suite 102 30 City,State,Zip: Raleigh,NC 27607 31 Phone number(s): 919-866-4937 32 Email: jacob.dooley@timmons.com Certification Statement: I certify,under penalty of law that this Supplement-EZ form and all supporting information were prepared under my direction or supervision;that the information provided in the form is,to the best of my knowledge and belief,true,accurate,and complete;and that the engineering plans, specifications,operation and maintenance agreements and other supporting information are consistent with the information provided here. Designer Signature of Designer Seal Date DRAINAGE AREAS 1 Is this a high density project? Yes 2 If so,number of drainage areas/SCMs _ 4 3 Does this project have low density areas? _ No 4 If so,number of low density drainage areas _ 0 Is all/part of this project subject to previous rule 5 versions? No FORMS LOADED DRAINAGE AREA INFORMATION Entire Site 1 2 3 4 4 Type of SCM Bioretention Cell N/A(Bypass) 5 Total drainage area(sq ft) 34202 22300 11902 6 Onsite drainage area(sq ft) 30503 19291 11212 7 Offsite drainage area(sq ft) 3699 3016 683 8 Total BUA in project(sq ft) 12004 sf 11878 sf 126 sf New BUA on subdivided lots(subject to 9 permitting)(sq ft) New BUA not on subdivided lots(subject to 10 permitting)(sf) 11889 sf 11878 sf 11 sf 11 Offsite BUA(sq ft) 2835 sf 2554 sf 281 sf 12 Breakdown of new BUA not on subdivided lots: -Parking(sq ft) 13179 sf 10625 sf 2554 sf -Sidewalk(sq ft) 412 sf 412 sf -Roof(sgft) 816sf 816sf -Roadway(sq ft) -Future(sq ft) 1307 sf 1307 sf -Other,please specify in the comment box below(sq ft) New infiltrating permeable pavement on 13 subdivided lots(sq ft) New infiltrating permeable pavement not on 14 subdivided lots(sq ft) Existing BUA that will remain(not subject to 15 permitting)(sq ft) 16 Existing BUA that is already permitted(sq ft) 1403 sf 17 Existing BUA that will be removed(sq ft) 1403 sf 18 Percent BUA 62% 19 Design storm(inches) 1.0 in 20 Design volume of SCM(cu ft) 1502 cf 21 Calculation method for design volume Simple Method ADDITIONAL INFORMATION Please use this space to provide any additional information about the 22 drainage area(s): BIORETENTION CELL 1 Drainage area number 1 2 Minimum required treatment volume(cu ft) 1232 cf GENERAL MDC FROM 02H.1050 3 Is the SCM sized to treat the SW from all surfaces at build-out? Yes 4 Is the SCM located away from contaminated soils? Yes 5 What are the side slopes of the SCM(H:V)? 3:1 6 Does the SCM have retaining walls,gabion walls or other engineered side slopes? No Are the inlets,outlets,and receiving stream protected from erosion 7 (10-year storm)? Yes _ 8 Is there an overflow or bypass for inflow volume in excess of the design volume? Yes 9 What is the method for dewatering the SCM for maintenance? Pump(preferred) 10 If applicable,will the SCM be cleaned out after construction? Yes 11 Does the maintenance access comply with General MDC(8)? Yes _ 12 Does the drainage easement comply with General MDC(9)? Yes If the SCM is on a single family lot,does(will?)the plat comply with 13 General MDC(10)? N/A 14 Is there an O&M Agreement that complies with General MDC(11)? Yes 15 Is there an O&M Plan that complies with General MDC(12)? Yes _ 16 Does the SCM follow the device specific MDC? Yes 17 Was the SCM designed by an NC licensed professional? Yes BIORETENTION CELL MDC FROM 02H.1052 18 SHWT elevation(fmsl) TBD 19 Bottom of the bioretention cell(fmsl) 880.83 _ 20 Ponding depth of the design storm(inches) 12 in _ 21 Surface area of the bioretention cell(square feet) 1724 sf 22 Design volume of SCM(cu ft) 1502 cf 23 Is the bioretention cell used for peak attenuation? Yes 24 Depth of peak attenuation over planting surface(in) 24 in _ 25 Height of peak attenuation outlet above the planting surface(in) 18 in 26 Infiltration rate of the in situ soil(inch/hour) TBD 27 Diameter of the underdrain pipes(if applicable) 4 in 28 Does the design include Internal Water Storage(IWS)? Yes 29 if so,elevation of the top of the IWS(fmsl) 883.5 _ 30 Elevation of the planting surface(fmsl) 885 _ 31 What type of vegetation will be planted? (grass,trees/shrubs, other)? Grass _ 32 Media depth(inches) 30 in _ 33 Percentage of medium to coarse washed sand by volume 75-85% 34 Percentage of fines(silt and clay)by volume 8-10% 35 Percentage of organic matter by volume 5-10% 36 Type of organic material Pine bark fines_ 37 Phosphorus Index(P-Index)of media(unitless) <50 _ 38 Will compaction be avoided during construction? Yes _ 39 Will cell be maintained to a one inch/hour standard? Yes _ 40 Depth of mulch,if applicable(inches) N/A _ 41 Type of mulch,if applicable N/A 42 How many clean out pipes are being installed? 2 Grass/Gravel 43 Type of pretreatment that will be used: Combination ADDITIONAL INFORMATION 44 Please use this space to provide any additional information about the bioretention cell(s): Bioretention 3 11:14 AM 5/2/2023 Circle K—Expansion 2723205 Winston-Salem, NC Project Number:37630.142 Stormwater Operation & Maintenance Agreement ,•••s•. . TIMMONS GROUP 6 I www.timmons.com YOUR VISION ACHIEVED THROUGH OURS. uperation at maintenance Agreement Project Name: Circle K - Expansion 2723205 Old US HWY 52 & Hickory Tree Rd Project Location: 106 Hickory Tree Rd, Winston-Salem, NC 27107 Cover Page laintenance records shall be kept on the following SCM(s). This maintenance record shall be kept in a log in a known set location. ,ny deficient SCM elements noted in the inspection will be corrected, repaired, or replaced immediately. These deficiencies can ffect the integrity of structures, safety of the public, and the pollutant removal efficiency of the SCM(s). he SCM(s) on this project include (check all that apply&corresponding O&M sheets will be added automatically): Infiltration Basin Quantity: Location(s): Infiltration Trench Quantity: Location(s): Bioretention Cell Quantity: 1 Location(s): Northwest corner of the property Wet Pond Quantity: Location(s): Stormwater Wetland Quantity: Location(s): Permeable Pavement Quantity: Location(s): Sand Filter Quantity: Location(s): Rainwater Harvesting Quantity: Location(s): Green Roof Quantity: Location(s): Level Spreader- Filter Strip Quantity: Location(s): Proprietary System Quantity: Location(s): Treatment Swale Quantity: Location(s): Dry Pond Quantity: Location(s): Disconnected Impervious Surface Present: No Location(s): User Defined SCM Present: No Location(s): Low Density Present: No Type: acknowledge and agree by my signature below that I am responsible for the performance of the maintenance procedures listed for ach SCM above, and attached O&M tables. I agree to notify NCDEQ of any problems with the system or prior to any changes to le system or responsible party. Responsible Party: Meredith Will Rice,Jr. Title &Organization: Vice President-Circle K Stores, Inc. Street address: 1100 Situs Court; Suite 100 City, state, zip: Raleigh, NC 27606 Phone number(s): 919-774-6700 Email: wrice@circlek.com Signature: // ` Date: 5 i( o ;" 2 L, n d A I ; (�r-U-v e- , a Notary Public for the State of 1\3 G fl 014 f ) 11 n rt W :ounty of W , do hereby certify that ��€.c L' cS -�h , it qc i L e ,1 t rJ ersonally appeared before me this ti it day of ( ,J , ,.0, 3 and cknowledge the due execution of the 0 rations and Maintenance Agreement . fitness my h� ileac cial seal, �/J? ,.A /� , 31,4)--7 _ „, i • o NOTARY PUBOO eal My commission expires I I "Ir I f�0 0 73 "ORM-EZ 4/19/20 Bioretention Maintenance Requirements Important operation and maintenance procedures: Immediately after the bioretention cell is established, the plants will be watered twice weekly if needed - until the plants become established (commonly six weeks). - Snow, mulch or any other material will NEVER be piled on the surface of the bioretention cell. - Heavy equipment will NEVER be driven over the bioretention cell. - Special care will be taken to prevent sediment from entering the bioretention cell. - Once a year, a soil test of the soil media will be conducted. Remove top layer of fill media when the pool does not drain quickly. Based on the media specification, - the pool should drain within 24 hours. After the bioretention cell is established, it will be inspected quarterly and within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a Coastal County). Records of operation and maintenance shall be kept in a known set location and shall be available upon request. Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately. SCM element: Potential problem: How to remediate the problem: The entire bioretention Trash/debris is present. Remove the trash/debris. cell The perimeter of the Areas of bare soil and/or Regrade the soil if necessary to remove the gully, plant ground bioretention cell erosive gullies have cover and water until it is established. Provide lime and a one-time formed. fertilizer application. • The structure is clogged. Unclog the structure and dispose of any sediment off-site. The flow diversion structure (if applicable) The structure is damaged. Make any necessary repairs or replace if the damage is too much for repair. The inlet pipe is clogged (if Unclog the pipe and dispose of any sediment in a location where it applicable). will not cause impacts to streams or the SCM. The inlet pipe is cracked or otherwise damaged (if Repair or replace the pipe. applicable). The inlet device Regrade the swale if necessary and provide erosion control Erosion is occurring in the devices such as reinforced turf matting or riprap to avoid future swale (if applicable). erosion problems. Stone verge is clogged or Remove sediment and clogged stone and replace with clean covered in sediment (if applicable). stone. Flow is bypassing Regrade if necessary to route all flow to the pretreatment area. pretreatment area and/or Restabilize the area after grading. gullies have formed. Sediment has accumulated Search for the source of the sediment and remedy the problem if to a depth greater than possible. Remove the sediment and dispose of it in a location The pretreatment area three inches. where it will not cause impacts to streams or the SCM. Erosion has occurred. Provide additional erosion protection such as reinforced turf matting or riprap if needed to prevent future erosion problems. Weeds are present. Remove the weeds, preferably by hand. If pesticide is used, wipe it on the plants rather than spraying. 1 Bioretention Maintenance Requirements (continued) SCM element: Potential problem: How to remediate the problem: Best professional practices show that pruning is Prune according to best professional practices. Maintain lines of needed to maintain optimal sight between 2'-6'. plant health. Determine the source of the problem: soils, hydrology, disease, etc. Remedy the problem and replace plants. Provide a one-time Bioretention cell Plants are dead, diseased fertilizer application to establish the ground cover if a soil test vegetation or dying. indicates it is necessary. If sod was used, check to see that it was not grown on clay or impermeable soils. Replace sod if necessary. Weeds are present. Remove the weeds, preferably by hand. If pesticide is used, wipe it on the plants rather than spraying. Tree stakes/wires are present six months after Remove tree stake/wires (which can kill the tree if not removed). planting. • Spot mulch if there are only random void areas. Replace whole Mulch is breaking down or mulch layer if necessary. Remove the remaining mulch and has floated away. replace with triple shredded hard wood mulch at a maximum depth of four inches. Determine the extent of the clogging - remove and replace either Soils and/or mulch are just the top layers or the entire media as needed. Dispose of the Bioretention cell mulch spoil in an appropriate off-site location. Use triple shredded hard and media clogged with sediment. wood mulch at a maximum depth of four inches. Search for the source of the sediment and remedy the problem if possible. An annual soil test shows that pH has dropped or Dolomitic lime shall be applied as recommended per the soil test heavy metals have and toxic soils shall be removed, disposed of properly and accumulated in the soil replaced with new planting media. _media. Clogging has occurred. Wash out the underdrain system. The underdrain, filter Clean out the drop inlet. Dispose of the sediment in a location fabric element, and outlet Clogging has occurred. where it will not cause impacts to streams or the SCM.. system The drop inlet is damaged Repair or replace the drop inlet. Erosion or other signs of damage have occurred at Repair the damage and improve the flow dissipation structure. the outlet. The receiving water Discharges from the bioretention cell are causing erosion or Contact the local NCDEQ Regional Office. sedimentation in the receiving water. 1 Circle K—Expansion 2723205 Winston-Salem, NC Project Number: 37630.142 Hydraulic Grade Line Calculations Q10 Analysis Using Hydraflow Software .•••s•• • TIMMONS GROUP 71 www.timmons.com YOUR VISION ACHIEVED THROUGH OURS. Hydraflow Storm Sewers Extension for Autodesk® Civil 3D® Plan CB103 1 FES102 2 DI104 7 3 CB105 Project File: 37630.142-2023.05.02.stm Number of lines: 3 Date: 5/2/2023 Storm Sewers v2019.20 Hydraulic Grade Line Computations Pagel Line Size Q Downstream Len Upstream Check JL Minor coeff loss Invert HGL Depth Area Vel Vel EGL Sf Invert HGL Depth Area Vel Vel EGL Sf Ave Enrgy elev elev head elev elev elev head elev Sf loss (in) (cfs) (ft) (ft) (ft) (sqft) (ft/s) (ft) (ft) (%) (ft) (ft) (ft) (ft) (sqft) (ft/s) (ft) (ft) (%) (%) (ft) (K) (ft) 1 15 2.28 885.00 885.60 0.60 0.58 3.91 0.24 885.84 0.000 19.274 885.19 885.80 0.60** 0.59 3.89 0.24 886.03 0.000 0.000 n/a 1.07 n/a 2 15 1.01 885.19 885.80 0.60 0.33 1.71 0.14 885.94 0.000 63.011 885.82 886.21 j 0.39** 0.33 3.04 0.14 886.36 0.000 0.000 n/a 1.35 n/a 3 15 0.77 885.82 886.21 0.39 0.27 2.34 0.12 886.34 0.000 15.511 885.98 886.32 j 0.34** 0.27 2.82 0.12 886.44 0.000 0.000 n/a 1.00 0.12 Project File: 37630.142-2023.05.02.stm Number of lines:3 Run Date: 5/2/2023 Notes: ;**Critical depth.;j-Line contains hyd.jump ; c=cir e=ellip b=box Storm Sewers v2019.20 Storm Sewer Profile Proj. file: 37630.142 -2023.05.02.stm FES102 CB103 D1104 CB105 N CO CCSC 7 7 C C 7 O C J 0 C J Q C J O W LO N coLoLo N coo. cLo cot Elev. (ft) DI 0' °° o -o w o Www o www o Ww m E j co E » co E >: m E >: ci) 0 E ci) E E E co E E E co E E 897.00 897.00 894.00 894.00 891.00 891.00 — —888.00 888.00 885.00 0� 63.011 Lf-15"@ 1.00% 885.00 19.274E - _ • • 15.611•Lf 15"@ 1.00% 882.00 882.00 0 10 20 30 40 50 60 70 80 90 100 HGL EGL Reach (ft) Storm Sewers