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TWAS Market St - Stormwater Report - 230111 DRAINAGE REPORT FOR TIDAL WAVE AUTO SPA Market Street Wilmington, North Carolina January 11, 2023 Prepared for: SHJ Construction Group 124 E Thompson St. Thomaston, GA 30286 Prepared by: Tommie L. (Trey) Little III, P.E. SeamonWhiteside 230 E Peterson Dr Charlotte, NC 28217 NCBEL # C-2466 EXECUTIVE SUMMARY Introduction The project is consisted of (2) properties (to be recombined with this project). Combined these properties are 1.75 acres. The properties are defined as New Hanover County Parcels R03600-003-074-000 & R03600-003-075-000. The properties are located in the B-1 zoning district and SHO overlay district. The proposed improvements will include the development of 1 car wash facility building, vacuum equipment building, associated parking areas, and necessary infrastructure. Existing Site Conditions Watersheds, Buffers, and Flood Plains The 1.75 acres project is located within the Pages Creek Watershed District. There are no waterways nor wetlands located onsite. Soils Based on the Natural Resources Conservation Service (NRCS) “Web Soil Survey” for the site, the soils located within the project area are defined as Leon Sand (Le) and Murville fine sand (Mu). The Web Soil Survey for the site is included in the Appendix of this report. Proposed Site Conditions Improvements The proposed improvements to the project include demolition of all existing site features, and the development of a car wash building, associated parking areas, and associated infrastructure. Drainage Any water falling on the roof of the proposed buildings and site impervious areas will be conveyed to 1 of 4 onsite Contech Filterra Water Quality devices, then to a proposed underground detention conveyance system before flowing to the existing floodplain and eventual Pages Creek. Proposed Stormwater Management Stormwater Quality and Detention The project site shall abide by the New Hanover County Stormwater Design Manual, as well as NCDEQ MDCs. All existing and proposed drainage areas are being evaluated at the Points of Interest described in the Drainage Section of this report above. Existing and Proposed Drainage Basins are shown along with the corresponding Points of Interest on the Pre- and Post-Development Maps included in Appendix. Curve number and time of concentration calculations are included in Appendix. Routing calculations were performed with HydroCAD using an SCS Methodology and a 24-hour hydrograph (based on NOAA Atlas 15 depths) as described in the County stormwater design manual. The BMP Calculations included in Appendix demonstrate compliance with the applicable requirements described in this report for the BMP requirements. Water Quality calculations are provided in the Appendix of this report. A summary of the results is shown in the Table below: POI 1 Pre and Post Development Runoff Summary Design Storm Pre-Developed Flow (cfs) Post Developed Flow (cfs) 2 Year 4.98 2.86 10 Year 9.29 7.58 25 Year 12.45 12.37 Erosion Control Erosion and sediment control measures during construction will be accomplished using temporary and permanent best management practices (BMPs). Temporary best management practices include the utilization of a silt fence, inlet protection, skimmer basin, and temporary seeding during construction. Permanent best management practices include the permanent seeding and stabilization of the site. The erosion control sediment basin calculations has been included in Appendix. Stormwater Conveyance The stormwater conveyance pipe system was designed to convey the 25-year, 24-hour storm event. The pipe modeling software, Hydraflow Storm Sewers, has been used for the design of the proposed storm drainage pipes and inlets for the site (stormwater conveyance system). Storm Sewers utilizes the Rational Method based on the 25-year, 24-hour storm event. The inlet spread for inlets within the site were not analyzed, as the parking area is private. No additional drainage is being sent towards Market Street curb inlets, therefore inlet spread was not analyzed there as well. The Hydraflow Storm Sewers report in Appendix. S S POI 1 AREA = 1.71 AC CN = 80 Tc = 18.7 Minutes C9.0 PRE DEVELOPMENT DRAINAGE MAP 10 20 40 SCALE: 1" = 20' 0 S E W N CO P Y R I G H T c S E A M O N , W H I T E S I D E & A S S O C I A T E S , I N C . TH I S D R A W I N G S H A L L N O T B E R E P R O D U C E D I N A N Y M A N N E R O R U S E D F O R A N Y P U R P O S E W I T H O U T W R I T T E N P E R M I S S I O N . 1/11/23 CL1326 ATZ DWJ 10/28/2022DATE: 50 1 W A N D O P A R K B O U L E V A R D , S U I T E 2 0 0 | M O U N T P L E A S A N T , S C 2 9 4 6 4 | 5 0 8 R H E T T S T R E E T , S U I T E 1 0 1 | G R E E N V I L L E , S C 2 9 6 0 1 WI L M I N G T O N @ M A R K E T S T R E E T WI L M I N G T O N , N O R T H C A R O L I N A TI D A L W A V E A U T O S P A REVISION HISTORY DRAWN BY: CHECKED BY: SW+ PROJECT: MOUNT PLEASANT, SC 843.884.1667 GREENVILLE, SC 864.298.0534 WWW.SEAMONWHITESIDE.COM SUMMERVILLE, SC 843.972.0710 SPARTANBURG, SC 864.272.1272 CHARLOTTE, NC 980.312.5450 NO. C-2466 SEAMON,N O R T H CAROLINA F O I WHITESIDE &ASSOCIATES, INC. T T IC C FAUTH O RIZATIONER AE 048282 SEALPROFESSIONA L ENGINEE R NO R T H CAROLIN A T O MMIE L.LI T TLE S S HC HC S 3 5 35 34 34 34 36 36 36 35 35 34 33 32 36 35 34 3333 32 31 30 29 30 31 32 33 34 35 28 33 34 33 INLET OUTLE T POI 1 TO BMP AREA = 1.155 AC CN = 94 Tc = 5 Minutes POI 1 BYPASS AREA = 0.55 AC CN = 80 Tc = 10.0 Minutes C9.1 POST DEVELOPMENT DRAINAGE MAPS 10 20 40 SCALE: 1" = 20' 0 S E W N CO P Y R I G H T c S E A M O N , W H I T E S I D E & A S S O C I A T E S , I N C . TH I S D R A W I N G S H A L L N O T B E R E P R O D U C E D I N A N Y M A N N E R O R U S E D F O R A N Y P U R P O S E W I T H O U T W R I T T E N P E R M I S S I O N . 1/11/23 CL1326 ATZ DWJ 10/28/2022DATE: 50 1 W A N D O P A R K B O U L E V A R D , S U I T E 2 0 0 | M O U N T P L E A S A N T , S C 2 9 4 6 4 | 5 0 8 R H E T T S T R E E T , S U I T E 1 0 1 | G R E E N V I L L E , S C 2 9 6 0 1 WI L M I N G T O N @ M A R K E T S T R E E T WI L M I N G T O N , N O R T H C A R O L I N A TI D A L W A V E A U T O S P A REVISION HISTORY DRAWN BY: CHECKED BY: SW+ PROJECT: MOUNT PLEASANT, SC 843.884.1667 GREENVILLE, SC 864.298.0534 WWW.SEAMONWHITESIDE.COM SUMMERVILLE, SC 843.972.0710 SPARTANBURG, SC 864.272.1272 CHARLOTTE, NC 980.312.5450 NO. C-2466 SEAMON,N O R T H CAROLINA F O I WHITESIDE &ASSOCIATES, INC. T T IC C FAUTH O RIZATIONER AE 048282 SEALPROFESSIONA L ENGINEE R NO R T H CAROLIN A T O MMIE L.LI T TLE Design Engineer:TKM Blue Cells =Input Date 10/7/2022 Black Cells =Calculation Site Information Project Name TWAS (North FT) Project State North Carolina Project Location Wilmington Drainage Area, Ad 0.22 ac Impervious Area, Ai 0.21 ac Impervious Runoff Coefficient, Ci 0.90 Pervious Area, Ap 0.01 Pervious Area Runoff Coefficient, Cp 0.30 % Impervious 95% Weighted Runoff Coefficient, Cw 0.87 Filterra Sizing Calculations Filter Surface Area / Drainage Area Ratio 0.39%Per NCDEQ Manual, Chapter D.3, Table 1 Required Filterra Media Surface Area,36 ft2 Filterra System Filterra Configuration Internal Bypass Curb Filterra Model ID FTIBC 6x6 Filterra Sizing in North Carolina ©2019 Contech Engineered Solutions ContechES.com 1 of 1 Design Engineer:TKM Blue Cells =Input Date 10/7/2022 Black Cells =Calculation Site Information Project Name TWAS (Northeast FT) Project State North Carolina Project Location Wilmington Drainage Area, Ad 0.24 ac Impervious Area, Ai 0.23 ac Impervious Runoff Coefficient, Ci 0.90 Pervious Area, Ap 0.01 Pervious Area Runoff Coefficient, Cp 0.30 % Impervious 96% Weighted Runoff Coefficient, Cw 0.88 Filterra Sizing Calculations Filter Surface Area / Drainage Area Ratio 0.39%Per NCDEQ Manual, Chapter D.3, Table 1 Required Filterra Media Surface Area,40 ft2 Filterra System Filterra Configuration Internal Bypass Curb Filterra Model ID FTIBC 6x8 / 8x6 Filterra Sizing in North Carolina ©2019 Contech Engineered Solutions ContechES.com 1 of 1 Design Engineer:TKM Blue Cells =Input Date 10/7/2022 Black Cells =Calculation Site Information Project Name TWAS (Southwest FT) Project State North Carolina Project Location Wilmington Drainage Area, Ad 0.25 ac Impervious Area, Ai 0.20 ac Impervious Runoff Coefficient, Ci 0.90 Pervious Area, Ap 0.05 Pervious Area Runoff Coefficient, Cp 0.30 % Impervious 80% Weighted Runoff Coefficient, Cw 0.78 Filterra Sizing Calculations Filter Surface Area / Drainage Area Ratio 0.39%Per NCDEQ Manual, Chapter D.3, Table 1 Required Filterra Media Surface Area,37 ft2 Filterra System Filterra Configuration Peak Diversion Filterra Model ID FTPD 6x8 Filterra Sizing in North Carolina ©2019 Contech Engineered Solutions ContechES.com 1 of 1 Design Engineer:TKM Blue Cells =Input Date 10/7/2022 Black Cells =Calculation Site Information Project Name TWAS (West FT) Project State North Carolina Project Location Wilmington Drainage Area, Ad 0.21 ac Impervious Area, Ai 0.20 ac Impervious Runoff Coefficient, Ci 0.90 Pervious Area, Ap 0.01 Pervious Area Runoff Coefficient, Cp 0.30 % Impervious 95% Weighted Runoff Coefficient, Cw 0.87 Filterra Sizing Calculations Filter Surface Area / Drainage Area Ratio 0.39%Per NCDEQ Manual, Chapter D.3, Table 1 Required Filterra Media Surface Area,35 ft2 Filterra System Filterra Configuration Internal Bypass Curb Filterra Model ID FTIBC 6x6 Filterra Sizing in North Carolina ©2019 Contech Engineered Solutions ContechES.com 1 of 1 1S pre poi 1 2S poi 1 to bmp 3S poi 1 bypass 5P BMP 1 4L poi 1 combined Routing Diagram for Market Street - hydrocad - 221214 Prepared by Seamon Whiteside, Printed 1/11/2023 HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Subcat Reach Pond Link Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 4HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Area Listing (selected nodes) Area (acres) CN Description (subcatchment-numbers) 2.485 80 >75% Grass cover, Good, HSG D (1S, 2S, 3S) 0.880 98 Paved parking, HSG B (2S) 0.050 98 ex driveway (1S, 2S) 3.415 85 TOTAL AREA Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 7HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Pipe Listing (selected nodes) Line# Node Number In-Invert (feet) Out-Invert (feet) Length (feet) Slope (ft/ft) n Width (inches) Diam/Height (inches) Inside-Fill (inches) 1 5P 28.00 27.80 21.0 0.0095 0.010 0.0 24.0 0.0 NOAA 24-hr A 2-yr Rainfall=4.69"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 8HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Time span=0.00-120.00 hrs, dt=0.05 hrs, 2401 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=1.710 ac 1.46% Impervious Runoff Depth=2.62"Subcatchment 1S: pre poi 1 Flow Length=442' Tc=18.7 min CN=80 Runoff=4.98 cfs 0.374 af Runoff Area=1.155 ac 78.35% Impervious Runoff Depth=4.00"Subcatchment 2S: poi 1 to bmp Tc=5.0 min CN=94 Runoff=7.30 cfs 0.385 af Runoff Area=0.550 ac 0.00% Impervious Runoff Depth=2.62"Subcatchment 3S: poi 1 bypass Tc=10.0 min CN=80 Runoff=2.08 cfs 0.120 af Peak Elev=29.15' Storage=0.235 af Inflow=7.30 cfs 0.385 afPond 5P: BMP 1 Outflow=0.90 cfs 0.309 af Inflow=2.86 cfs 0.429 afLink 4L: poi 1 combined Primary=2.86 cfs 0.429 af Total Runoff Area = 3.415 ac Runoff Volume = 0.879 af Average Runoff Depth = 3.09" 72.77% Pervious = 2.485 ac 27.23% Impervious = 0.930 ac NOAA 24-hr A 2-yr Rainfall=4.69"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 9HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: pre poi 1 Runoff = 4.98 cfs @ 12.28 hrs, Volume= 0.374 af, Depth= 2.62" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs NOAA 24-hr A 2-yr Rainfall=4.69" Area (ac) CN Description 1.685 80 >75% Grass cover, Good, HSG D * 0.025 98 ex driveway 1.710 80 Weighted Average 1.685 98.54% Pervious Area 0.025 1.46% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13.1 100 0.0100 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.12" 5.3 242 0.0120 0.77 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 0.3 100 0.0200 5.79 115.77 Channel Flow, Area= 20.0 sf Perim= 35.0' r= 0.57' n= 0.025 Earth, clean & winding 18.7 442 Total Subcatchment 1S: pre poi 1 Runoff Hydrograph Time (hours) 12011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 5 4 3 2 1 0 NOAA 24-hr A 2-yr Rainfall=4.69" Runoff Area=1.710 ac Runoff Volume=0.374 af Runoff Depth=2.62" Flow Length=442' Tc=18.7 min CN=80 4.98 cfs NOAA 24-hr A 2-yr Rainfall=4.69"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 10HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Hydrograph for Subcatchment 1S: pre poi 1 Time (hours) Precip. (inches) Excess (inches) Runoff (cfs) 0.00 0.00 0.00 0.00 2.50 0.09 0.00 0.00 5.00 0.20 0.00 0.00 7.50 0.35 0.00 0.00 10.00 0.64 0.01 0.02 12.50 3.52 1.65 2.85 15.00 4.19 2.20 0.19 17.50 4.41 2.38 0.10 20.00 4.54 2.49 0.07 22.50 4.64 2.58 0.05 25.00 4.69 2.62 0.00 27.50 4.69 2.62 0.00 30.00 4.69 2.62 0.00 32.50 4.69 2.62 0.00 35.00 4.69 2.62 0.00 37.50 4.69 2.62 0.00 40.00 4.69 2.62 0.00 42.50 4.69 2.62 0.00 45.00 4.69 2.62 0.00 47.50 4.69 2.62 0.00 50.00 4.69 2.62 0.00 52.50 4.69 2.62 0.00 55.00 4.69 2.62 0.00 57.50 4.69 2.62 0.00 60.00 4.69 2.62 0.00 62.50 4.69 2.62 0.00 65.00 4.69 2.62 0.00 67.50 4.69 2.62 0.00 70.00 4.69 2.62 0.00 72.50 4.69 2.62 0.00 75.00 4.69 2.62 0.00 77.50 4.69 2.62 0.00 80.00 4.69 2.62 0.00 82.50 4.69 2.62 0.00 85.00 4.69 2.62 0.00 87.50 4.69 2.62 0.00 90.00 4.69 2.62 0.00 92.50 4.69 2.62 0.00 95.00 4.69 2.62 0.00 97.50 4.69 2.62 0.00 100.00 4.69 2.62 0.00 102.50 4.69 2.62 0.00 105.00 4.69 2.62 0.00 107.50 4.69 2.62 0.00 110.00 4.69 2.62 0.00 112.50 4.69 2.62 0.00 115.00 4.69 2.62 0.00 117.50 4.69 2.62 0.00 120.00 4.69 2.62 0.00 NOAA 24-hr A 2-yr Rainfall=4.69"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 11HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: poi 1 to bmp [49] Hint: Tc<2dt may require smaller dt Runoff = 7.30 cfs @ 12.11 hrs, Volume= 0.385 af, Depth= 4.00" Routed to Pond 5P : BMP 1 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs NOAA 24-hr A 2-yr Rainfall=4.69" Area (ac) CN Description 0.880 98 Paved parking, HSG B * 0.025 98 ex driveway 0.250 80 >75% Grass cover, Good, HSG D 1.155 94 Weighted Average 0.250 21.65% Pervious Area 0.905 78.35% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 2S: poi 1 to bmp Runoff Hydrograph Time (hours) 12011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 8 7 6 5 4 3 2 1 0 NOAA 24-hr A 2-yr Rainfall=4.69" Runoff Area=1.155 ac Runoff Volume=0.385 af Runoff Depth=4.00" Tc=5.0 min CN=94 7.30 cfs NOAA 24-hr A 2-yr Rainfall=4.69"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 12HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Hydrograph for Subcatchment 2S: poi 1 to bmp Time (hours) Precip. (inches) Excess (inches) Runoff (cfs) 0.00 0.00 0.00 0.00 2.50 0.09 0.00 0.00 5.00 0.20 0.01 0.01 7.50 0.35 0.06 0.04 10.00 0.64 0.23 0.14 12.50 3.52 2.86 1.23 15.00 4.19 3.51 0.13 17.50 4.41 3.72 0.07 20.00 4.54 3.85 0.05 22.50 4.64 3.95 0.04 25.00 4.69 4.00 0.00 27.50 4.69 4.00 0.00 30.00 4.69 4.00 0.00 32.50 4.69 4.00 0.00 35.00 4.69 4.00 0.00 37.50 4.69 4.00 0.00 40.00 4.69 4.00 0.00 42.50 4.69 4.00 0.00 45.00 4.69 4.00 0.00 47.50 4.69 4.00 0.00 50.00 4.69 4.00 0.00 52.50 4.69 4.00 0.00 55.00 4.69 4.00 0.00 57.50 4.69 4.00 0.00 60.00 4.69 4.00 0.00 62.50 4.69 4.00 0.00 65.00 4.69 4.00 0.00 67.50 4.69 4.00 0.00 70.00 4.69 4.00 0.00 72.50 4.69 4.00 0.00 75.00 4.69 4.00 0.00 77.50 4.69 4.00 0.00 80.00 4.69 4.00 0.00 82.50 4.69 4.00 0.00 85.00 4.69 4.00 0.00 87.50 4.69 4.00 0.00 90.00 4.69 4.00 0.00 92.50 4.69 4.00 0.00 95.00 4.69 4.00 0.00 97.50 4.69 4.00 0.00 100.00 4.69 4.00 0.00 102.50 4.69 4.00 0.00 105.00 4.69 4.00 0.00 107.50 4.69 4.00 0.00 110.00 4.69 4.00 0.00 112.50 4.69 4.00 0.00 115.00 4.69 4.00 0.00 117.50 4.69 4.00 0.00 120.00 4.69 4.00 0.00 NOAA 24-hr A 2-yr Rainfall=4.69"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 13HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Summary for Subcatchment 3S: poi 1 bypass Runoff = 2.08 cfs @ 12.18 hrs, Volume= 0.120 af, Depth= 2.62" Routed to Link 4L : poi 1 combined Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs NOAA 24-hr A 2-yr Rainfall=4.69" Area (ac) CN Description 0.550 80 >75% Grass cover, Good, HSG D 0.550 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment 3S: poi 1 bypass Runoff Hydrograph Time (hours) 12011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 2 1 0 NOAA 24-hr A 2-yr Rainfall=4.69" Runoff Area=0.550 ac Runoff Volume=0.120 af Runoff Depth=2.62" Tc=10.0 min CN=80 2.08 cfs NOAA 24-hr A 2-yr Rainfall=4.69"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 14HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Hydrograph for Subcatchment 3S: poi 1 bypass Time (hours) Precip. (inches) Excess (inches) Runoff (cfs) 0.00 0.00 0.00 0.00 2.50 0.09 0.00 0.00 5.00 0.20 0.00 0.00 7.50 0.35 0.00 0.00 10.00 0.64 0.01 0.01 12.50 3.52 1.65 0.56 15.00 4.19 2.20 0.06 17.50 4.41 2.38 0.03 20.00 4.54 2.49 0.02 22.50 4.64 2.58 0.02 25.00 4.69 2.62 0.00 27.50 4.69 2.62 0.00 30.00 4.69 2.62 0.00 32.50 4.69 2.62 0.00 35.00 4.69 2.62 0.00 37.50 4.69 2.62 0.00 40.00 4.69 2.62 0.00 42.50 4.69 2.62 0.00 45.00 4.69 2.62 0.00 47.50 4.69 2.62 0.00 50.00 4.69 2.62 0.00 52.50 4.69 2.62 0.00 55.00 4.69 2.62 0.00 57.50 4.69 2.62 0.00 60.00 4.69 2.62 0.00 62.50 4.69 2.62 0.00 65.00 4.69 2.62 0.00 67.50 4.69 2.62 0.00 70.00 4.69 2.62 0.00 72.50 4.69 2.62 0.00 75.00 4.69 2.62 0.00 77.50 4.69 2.62 0.00 80.00 4.69 2.62 0.00 82.50 4.69 2.62 0.00 85.00 4.69 2.62 0.00 87.50 4.69 2.62 0.00 90.00 4.69 2.62 0.00 92.50 4.69 2.62 0.00 95.00 4.69 2.62 0.00 97.50 4.69 2.62 0.00 100.00 4.69 2.62 0.00 102.50 4.69 2.62 0.00 105.00 4.69 2.62 0.00 107.50 4.69 2.62 0.00 110.00 4.69 2.62 0.00 112.50 4.69 2.62 0.00 115.00 4.69 2.62 0.00 117.50 4.69 2.62 0.00 120.00 4.69 2.62 0.00 NOAA 24-hr A 2-yr Rainfall=4.69"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 15HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Summary for Pond 5P: BMP 1 Inflow Area = 1.155 ac, 78.35% Impervious, Inflow Depth = 4.00" for 2-yr event Inflow = 7.30 cfs @ 12.11 hrs, Volume= 0.385 af Outflow = 0.90 cfs @ 12.60 hrs, Volume= 0.309 af, Atten= 88%, Lag= 29.3 min Primary = 0.90 cfs @ 12.60 hrs, Volume= 0.309 af Routed to Link 4L : poi 1 combined Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs Peak Elev= 29.15' @ 12.60 hrs Surf.Area= 0.191 ac Storage= 0.235 af Plug-Flow detention time= 224.6 min calculated for 0.308 af (80% of inflow) Center-of-Mass det. time= 166.0 min ( 933.3 - 767.3 ) Volume Invert Avail.Storage Storage Description #1A 27.00' 0.301 af 45.58'W x 182.92'L x 5.92'H Field A 1.133 af Overall - 0.381 af Embedded = 0.752 af x 40.0% Voids #2A 28.00' 0.381 af CMP Arch 71x47 x 45 Inside #1 Effective Size= 71.0"W x 47.0"H => 18.31 sf x 20.00'L = 366.1 cf Overall Size= 71.0"W x 47.0"H x 20.00'L Row Length Adjustment= -7.00' x 18.31 sf x 5 rows 41.58' Header x 18.31 sf x 1 = 761.3 cf Inside 0.682 af Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Primary 28.00'24.0" Round Culvert L= 21.0' RCP, groove end projecting, Ke= 0.200 Inlet / Outlet Invert= 28.00' / 27.80' S= 0.0095 '/' Cc= 0.900 n= 0.010, Flow Area= 3.14 sf #2 Device 1 28.00'6.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Device 1 29.25'2.5' long Sharp-Crested Rectangular Weir 0 End Contraction(s) Primary OutFlow Max=0.90 cfs @ 12.60 hrs HW=29.15' (Free Discharge) 1=Culvert (Passes 0.90 cfs of 6.22 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.90 cfs @ 4.58 fps) 3=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs) NOAA 24-hr A 2-yr Rainfall=4.69"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 16HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Pond 5P: BMP 1 - Chamber Wizard Field A Chamber Model = CMP Arch 71x47 (1/2" Corrugated Pipe Arch, AISI Handbook 1994, Table 2.18) Effective Size= 71.0"W x 47.0"H => 18.31 sf x 20.00'L = 366.1 cf Overall Size= 71.0"W x 47.0"H x 20.00'L Row Length Adjustment= -7.00' x 18.31 sf x 5 rows 71.0" Wide + 36.0" Spacing = 107.0" C-C Row Spacing 9 Chambers/Row x 20.00' Long -7.00' Row Adjustment +5.92' Header x 1 = 178.92' Row Length +24.0" End Stone x 2 = 182.92' Base Length 5 Rows x 71.0" Wide + 36.0" Spacing x 4 + 24.0" Side Stone x 2 = 45.58' Base Width 12.0" Stone Base + 47.0" Chamber Height + 12.0" Stone Cover = 5.92' Field Height 45 Chambers x 366.1 cf -7.00' Row Adjustment x 18.31 sf x 5 Rows + 41.58' Header x 18.31 sf = 16,597.0 cf Chamber Storage 49,332.9 cf Field - 16,597.0 cf Chambers = 32,735.8 cf Stone x 40.0% Voids = 13,094.3 cf Stone Storage Chamber Storage + Stone Storage = 29,691.4 cf = 0.682 af Overall Storage Efficiency = 60.2% Overall System Size = 182.92' x 45.58' x 5.92' 45 Chambers 1,827.1 cy Field 1,212.4 cy Stone NOAA 24-hr A 2-yr Rainfall=4.69"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 17HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Pond 5P: BMP 1 Inflow Primary Hydrograph Time (hours) 12011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 8 7 6 5 4 3 2 1 0 Inflow Area=1.155 ac Peak Elev=29.15' Storage=0.235 af 7.30 cfs 0.90 cfs Pond 5P: BMP 1 Primary Stage-Discharge Discharge (cfs) 35302520151050 El e v a t i o n ( f e e t ) 32 31 30 29 28 27 Culvert + Orifice/Grate Sharp-Crested Rectangular Weir NOAA 24-hr A 2-yr Rainfall=4.69"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 19HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Hydrograph for Pond 5P: BMP 1 Time (hours) Inflow (cfs) Storage (acre-feet) Elevation (feet) Primary (cfs) 0.00 0.00 0.000 27.00 0.00 2.50 0.00 0.000 27.00 0.00 5.00 0.01 0.001 27.01 0.00 7.50 0.04 0.005 27.07 0.00 10.00 0.14 0.021 27.28 0.00 12.50 1.23 0.234 29.14 0.89 15.00 0.13 0.149 28.57 0.53 17.50 0.07 0.104 28.25 0.16 20.00 0.05 0.094 28.16 0.08 22.50 0.04 0.090 28.13 0.05 25.00 0.00 0.086 28.10 0.03 27.50 0.00 0.082 28.06 0.01 30.00 0.00 0.081 28.04 0.01 32.50 0.00 0.079 28.03 0.00 35.00 0.00 0.079 28.03 0.00 37.50 0.00 0.078 28.02 0.00 40.00 0.00 0.078 28.02 0.00 42.50 0.00 0.078 28.01 0.00 45.00 0.00 0.077 28.01 0.00 47.50 0.00 0.077 28.01 0.00 50.00 0.00 0.077 28.01 0.00 52.50 0.00 0.077 28.01 0.00 55.00 0.00 0.077 28.01 0.00 57.50 0.00 0.077 28.01 0.00 60.00 0.00 0.077 28.01 0.00 62.50 0.00 0.077 28.01 0.00 65.00 0.00 0.077 28.01 0.00 67.50 0.00 0.077 28.01 0.00 70.00 0.00 0.077 28.00 0.00 72.50 0.00 0.077 28.00 0.00 75.00 0.00 0.077 28.00 0.00 77.50 0.00 0.077 28.00 0.00 80.00 0.00 0.077 28.00 0.00 82.50 0.00 0.077 28.00 0.00 85.00 0.00 0.077 28.00 0.00 87.50 0.00 0.077 28.00 0.00 90.00 0.00 0.077 28.00 0.00 92.50 0.00 0.077 28.00 0.00 95.00 0.00 0.077 28.00 0.00 97.50 0.00 0.077 28.00 0.00 100.00 0.00 0.077 28.00 0.00 102.50 0.00 0.077 28.00 0.00 105.00 0.00 0.077 28.00 0.00 107.50 0.00 0.077 28.00 0.00 110.00 0.00 0.077 28.00 0.00 112.50 0.00 0.077 28.00 0.00 115.00 0.00 0.077 28.00 0.00 117.50 0.00 0.077 28.00 0.00 120.00 0.00 0.077 28.00 0.00 NOAA 24-hr A 2-yr Rainfall=4.69"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 20HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Stage-Discharge for Pond 5P: BMP 1 Elevation (feet) Primary (cfs) 27.00 0.00 27.05 0.00 27.10 0.00 27.15 0.00 27.20 0.00 27.25 0.00 27.30 0.00 27.35 0.00 27.40 0.00 27.45 0.00 27.50 0.00 27.55 0.00 27.60 0.00 27.65 0.00 27.70 0.00 27.75 0.00 27.80 0.00 27.85 0.00 27.90 0.00 27.95 0.00 28.00 0.00 28.05 0.01 28.10 0.03 28.15 0.07 28.20 0.11 28.25 0.17 28.30 0.23 28.35 0.30 28.40 0.36 28.45 0.43 28.50 0.47 28.55 0.52 28.60 0.56 28.65 0.60 28.70 0.63 28.75 0.67 28.80 0.70 28.85 0.73 28.90 0.76 28.95 0.79 29.00 0.82 29.05 0.85 29.10 0.87 29.15 0.90 29.20 0.92 29.25 0.95 29.30 1.06 29.35 1.25 29.40 1.49 29.45 1.77 29.50 2.08 29.55 2.42 29.60 2.79 Elevation (feet) Primary (cfs) 29.65 3.19 29.70 3.61 29.75 4.05 29.80 4.51 29.85 5.00 29.90 5.50 29.95 6.02 30.00 6.56 30.05 7.12 30.10 7.69 30.15 8.28 30.20 8.89 30.25 9.51 30.30 10.15 30.35 10.80 30.40 11.47 30.45 12.15 30.50 12.84 30.55 13.55 30.60 14.27 30.65 15.01 30.70 15.75 30.75 16.51 30.80 17.29 30.85 18.07 30.90 18.87 30.95 19.67 31.00 20.49 31.05 21.32 31.10 22.17 31.15 23.02 31.20 23.88 31.25 24.76 31.30 25.65 31.35 26.54 31.40 27.40 31.45 27.82 31.50 28.24 31.55 28.65 31.60 29.06 31.65 29.46 31.70 29.86 31.75 30.25 31.80 30.63 31.85 31.01 31.90 31.39 31.95 31.76 32.00 32.13 32.05 32.49 32.10 32.85 32.15 33.20 32.20 33.55 32.25 33.90 Elevation (feet) Primary (cfs) 32.30 34.25 32.35 34.59 32.40 34.87 32.45 35.12 32.50 35.37 32.55 35.63 32.60 35.88 32.65 36.12 32.70 36.37 32.75 36.62 32.80 36.86 32.85 37.10 32.90 37.34 NOAA 24-hr A 2-yr Rainfall=4.69"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 21HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond 5P: BMP 1 Elevation (feet) Storage (acre-feet) 27.00 0.000 27.05 0.004 27.10 0.008 27.15 0.011 27.20 0.015 27.25 0.019 27.30 0.023 27.35 0.027 27.40 0.031 27.45 0.034 27.50 0.038 27.55 0.042 27.60 0.046 27.65 0.050 27.70 0.054 27.75 0.057 27.80 0.061 27.85 0.065 27.90 0.069 27.95 0.073 28.00 0.077 28.05 0.081 28.10 0.086 28.15 0.092 28.20 0.098 28.25 0.105 28.30 0.111 28.35 0.118 28.40 0.125 28.45 0.132 28.50 0.139 28.55 0.146 28.60 0.153 28.65 0.160 28.70 0.168 28.75 0.175 28.80 0.182 28.85 0.190 28.90 0.197 28.95 0.205 29.00 0.212 29.05 0.220 29.10 0.227 29.15 0.235 29.20 0.242 29.25 0.250 29.30 0.257 29.35 0.265 29.40 0.272 29.45 0.280 29.50 0.287 29.55 0.295 29.60 0.302 Elevation (feet) Storage (acre-feet) 29.65 0.310 29.70 0.317 29.75 0.324 29.80 0.332 29.85 0.339 29.90 0.347 29.95 0.354 30.00 0.361 30.05 0.369 30.10 0.376 30.15 0.383 30.20 0.390 30.25 0.398 30.30 0.405 30.35 0.412 30.40 0.419 30.45 0.426 30.50 0.433 30.55 0.440 30.60 0.447 30.65 0.454 30.70 0.461 30.75 0.468 30.80 0.474 30.85 0.481 30.90 0.488 30.95 0.494 31.00 0.501 31.05 0.507 31.10 0.514 31.15 0.520 31.20 0.526 31.25 0.533 31.30 0.539 31.35 0.545 31.40 0.551 31.45 0.557 31.50 0.562 31.55 0.568 31.60 0.574 31.65 0.579 31.70 0.584 31.75 0.590 31.80 0.595 31.85 0.599 31.90 0.604 31.95 0.608 32.00 0.611 32.05 0.615 32.10 0.619 32.15 0.623 32.20 0.627 32.25 0.631 Elevation (feet) Storage (acre-feet) 32.30 0.634 32.35 0.638 32.40 0.642 32.45 0.646 32.50 0.650 32.55 0.654 32.60 0.657 32.65 0.661 32.70 0.665 32.75 0.669 32.80 0.673 32.85 0.677 32.90 0.680 NOAA 24-hr A 2-yr Rainfall=4.69"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 22HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Summary for Link 4L: poi 1 combined Inflow Area = 1.705 ac, 53.08% Impervious, Inflow Depth = 3.02" for 2-yr event Inflow = 2.86 cfs @ 12.19 hrs, Volume= 0.429 af Primary = 2.86 cfs @ 12.19 hrs, Volume= 0.429 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs Link 4L: poi 1 combined Inflow Primary Hydrograph Time (hours) 12011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 3 2 1 0 Inflow Area=1.705 ac 2.86 cfs2.86 cfs NOAA 24-hr A 2-yr Rainfall=4.69"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 23HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Hydrograph for Link 4L: poi 1 combined Time (hours) Inflow (cfs) Elevation (feet) Primary (cfs) 0.00 0.00 0.00 0.00 2.50 0.00 0.00 0.00 5.00 0.00 0.00 0.00 7.50 0.00 0.00 0.00 10.00 0.01 0.00 0.01 12.50 1.45 0.00 1.45 15.00 0.59 0.00 0.59 17.50 0.19 0.00 0.19 20.00 0.10 0.00 0.10 22.50 0.07 0.00 0.07 25.00 0.03 0.00 0.03 27.50 0.01 0.00 0.01 30.00 0.01 0.00 0.01 32.50 0.00 0.00 0.00 35.00 0.00 0.00 0.00 37.50 0.00 0.00 0.00 40.00 0.00 0.00 0.00 42.50 0.00 0.00 0.00 45.00 0.00 0.00 0.00 47.50 0.00 0.00 0.00 50.00 0.00 0.00 0.00 52.50 0.00 0.00 0.00 55.00 0.00 0.00 0.00 57.50 0.00 0.00 0.00 60.00 0.00 0.00 0.00 62.50 0.00 0.00 0.00 65.00 0.00 0.00 0.00 67.50 0.00 0.00 0.00 70.00 0.00 0.00 0.00 72.50 0.00 0.00 0.00 75.00 0.00 0.00 0.00 77.50 0.00 0.00 0.00 80.00 0.00 0.00 0.00 82.50 0.00 0.00 0.00 85.00 0.00 0.00 0.00 87.50 0.00 0.00 0.00 90.00 0.00 0.00 0.00 92.50 0.00 0.00 0.00 95.00 0.00 0.00 0.00 97.50 0.00 0.00 0.00 100.00 0.00 0.00 0.00 102.50 0.00 0.00 0.00 105.00 0.00 0.00 0.00 107.50 0.00 0.00 0.00 110.00 0.00 0.00 0.00 112.50 0.00 0.00 0.00 115.00 0.00 0.00 0.00 117.50 0.00 0.00 0.00 120.00 0.00 0.00 0.00 NOAA 24-hr A 10-yr Rainfall=7.28"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 24HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Time span=0.00-120.00 hrs, dt=0.05 hrs, 2401 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=1.710 ac 1.46% Impervious Runoff Depth=4.95"Subcatchment 1S: pre poi 1 Flow Length=442' Tc=18.7 min CN=80 Runoff=9.29 cfs 0.706 af Runoff Area=1.155 ac 78.35% Impervious Runoff Depth=6.57"Subcatchment 2S: poi 1 to bmp Tc=5.0 min CN=94 Runoff=11.63 cfs 0.632 af Runoff Area=0.550 ac 0.00% Impervious Runoff Depth=4.95"Subcatchment 3S: poi 1 bypass Tc=10.0 min CN=80 Runoff=3.87 cfs 0.227 af Peak Elev=29.76' Storage=0.325 af Inflow=11.63 cfs 0.632 afPond 5P: BMP 1 Outflow=4.11 cfs 0.555 af Inflow=7.58 cfs 0.782 afLink 4L: poi 1 combined Primary=7.58 cfs 0.782 af Total Runoff Area = 3.415 ac Runoff Volume = 1.565 af Average Runoff Depth = 5.50" 72.77% Pervious = 2.485 ac 27.23% Impervious = 0.930 ac NOAA 24-hr A 10-yr Rainfall=7.28"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 25HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: pre poi 1 Runoff = 9.29 cfs @ 12.28 hrs, Volume= 0.706 af, Depth= 4.95" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs NOAA 24-hr A 10-yr Rainfall=7.28" Area (ac) CN Description 1.685 80 >75% Grass cover, Good, HSG D * 0.025 98 ex driveway 1.710 80 Weighted Average 1.685 98.54% Pervious Area 0.025 1.46% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13.1 100 0.0100 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.12" 5.3 242 0.0120 0.77 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 0.3 100 0.0200 5.79 115.77 Channel Flow, Area= 20.0 sf Perim= 35.0' r= 0.57' n= 0.025 Earth, clean & winding 18.7 442 Total Subcatchment 1S: pre poi 1 Runoff Hydrograph Time (hours) 12011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 10 9 8 7 6 5 4 3 2 1 0 NOAA 24-hr A 10-yr Rainfall=7.28" Runoff Area=1.710 ac Runoff Volume=0.706 af Runoff Depth=4.95" Flow Length=442' Tc=18.7 min CN=80 9.29 cfs NOAA 24-hr A 10-yr Rainfall=7.28"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 26HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Hydrograph for Subcatchment 1S: pre poi 1 Time (hours) Precip. (inches) Excess (inches) Runoff (cfs) 0.00 0.00 0.00 0.00 2.50 0.13 0.00 0.00 5.00 0.31 0.00 0.00 7.50 0.55 0.00 0.00 10.00 1.00 0.08 0.12 12.50 5.47 3.30 5.12 15.00 6.51 4.24 0.32 17.50 6.84 4.55 0.17 20.00 7.05 4.74 0.12 22.50 7.20 4.88 0.09 25.00 7.28 4.95 0.00 27.50 7.28 4.95 0.00 30.00 7.28 4.95 0.00 32.50 7.28 4.95 0.00 35.00 7.28 4.95 0.00 37.50 7.28 4.95 0.00 40.00 7.28 4.95 0.00 42.50 7.28 4.95 0.00 45.00 7.28 4.95 0.00 47.50 7.28 4.95 0.00 50.00 7.28 4.95 0.00 52.50 7.28 4.95 0.00 55.00 7.28 4.95 0.00 57.50 7.28 4.95 0.00 60.00 7.28 4.95 0.00 62.50 7.28 4.95 0.00 65.00 7.28 4.95 0.00 67.50 7.28 4.95 0.00 70.00 7.28 4.95 0.00 72.50 7.28 4.95 0.00 75.00 7.28 4.95 0.00 77.50 7.28 4.95 0.00 80.00 7.28 4.95 0.00 82.50 7.28 4.95 0.00 85.00 7.28 4.95 0.00 87.50 7.28 4.95 0.00 90.00 7.28 4.95 0.00 92.50 7.28 4.95 0.00 95.00 7.28 4.95 0.00 97.50 7.28 4.95 0.00 100.00 7.28 4.95 0.00 102.50 7.28 4.95 0.00 105.00 7.28 4.95 0.00 107.50 7.28 4.95 0.00 110.00 7.28 4.95 0.00 112.50 7.28 4.95 0.00 115.00 7.28 4.95 0.00 117.50 7.28 4.95 0.00 120.00 7.28 4.95 0.00 NOAA 24-hr A 10-yr Rainfall=7.28"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 27HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: poi 1 to bmp [49] Hint: Tc<2dt may require smaller dt Runoff = 11.63 cfs @ 12.11 hrs, Volume= 0.632 af, Depth= 6.57" Routed to Pond 5P : BMP 1 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs NOAA 24-hr A 10-yr Rainfall=7.28" Area (ac) CN Description 0.880 98 Paved parking, HSG B * 0.025 98 ex driveway 0.250 80 >75% Grass cover, Good, HSG D 1.155 94 Weighted Average 0.250 21.65% Pervious Area 0.905 78.35% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 2S: poi 1 to bmp Runoff Hydrograph Time (hours) 12011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 13 12 11 10 9 8 7 6 5 4 3 2 1 0 NOAA 24-hr A 10-yr Rainfall=7.28" Runoff Area=1.155 ac Runoff Volume=0.632 af Runoff Depth=6.57" Tc=5.0 min CN=94 11.63 cfs NOAA 24-hr A 10-yr Rainfall=7.28"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 28HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Hydrograph for Subcatchment 2S: poi 1 to bmp Time (hours) Precip. (inches) Excess (inches) Runoff (cfs) 0.00 0.00 0.00 0.00 2.50 0.13 0.00 0.00 5.00 0.31 0.04 0.04 7.50 0.55 0.17 0.09 10.00 1.00 0.50 0.26 12.50 5.47 4.77 1.94 15.00 6.51 5.80 0.21 17.50 6.84 6.13 0.12 20.00 7.05 6.33 0.08 22.50 7.20 6.49 0.06 25.00 7.28 6.57 0.00 27.50 7.28 6.57 0.00 30.00 7.28 6.57 0.00 32.50 7.28 6.57 0.00 35.00 7.28 6.57 0.00 37.50 7.28 6.57 0.00 40.00 7.28 6.57 0.00 42.50 7.28 6.57 0.00 45.00 7.28 6.57 0.00 47.50 7.28 6.57 0.00 50.00 7.28 6.57 0.00 52.50 7.28 6.57 0.00 55.00 7.28 6.57 0.00 57.50 7.28 6.57 0.00 60.00 7.28 6.57 0.00 62.50 7.28 6.57 0.00 65.00 7.28 6.57 0.00 67.50 7.28 6.57 0.00 70.00 7.28 6.57 0.00 72.50 7.28 6.57 0.00 75.00 7.28 6.57 0.00 77.50 7.28 6.57 0.00 80.00 7.28 6.57 0.00 82.50 7.28 6.57 0.00 85.00 7.28 6.57 0.00 87.50 7.28 6.57 0.00 90.00 7.28 6.57 0.00 92.50 7.28 6.57 0.00 95.00 7.28 6.57 0.00 97.50 7.28 6.57 0.00 100.00 7.28 6.57 0.00 102.50 7.28 6.57 0.00 105.00 7.28 6.57 0.00 107.50 7.28 6.57 0.00 110.00 7.28 6.57 0.00 112.50 7.28 6.57 0.00 115.00 7.28 6.57 0.00 117.50 7.28 6.57 0.00 120.00 7.28 6.57 0.00 NOAA 24-hr A 10-yr Rainfall=7.28"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 29HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Summary for Subcatchment 3S: poi 1 bypass Runoff = 3.87 cfs @ 12.17 hrs, Volume= 0.227 af, Depth= 4.95" Routed to Link 4L : poi 1 combined Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs NOAA 24-hr A 10-yr Rainfall=7.28" Area (ac) CN Description 0.550 80 >75% Grass cover, Good, HSG D 0.550 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment 3S: poi 1 bypass Runoff Hydrograph Time (hours) 12011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 4 3 2 1 0 NOAA 24-hr A 10-yr Rainfall=7.28" Runoff Area=0.550 ac Runoff Volume=0.227 af Runoff Depth=4.95" Tc=10.0 min CN=80 3.87 cfs NOAA 24-hr A 10-yr Rainfall=7.28"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 30HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Hydrograph for Subcatchment 3S: poi 1 bypass Time (hours) Precip. (inches) Excess (inches) Runoff (cfs) 0.00 0.00 0.00 0.00 2.50 0.13 0.00 0.00 5.00 0.31 0.00 0.00 7.50 0.55 0.00 0.00 10.00 1.00 0.08 0.04 12.50 5.47 3.30 0.97 15.00 6.51 4.24 0.10 17.50 6.84 4.55 0.05 20.00 7.05 4.74 0.04 22.50 7.20 4.88 0.03 25.00 7.28 4.95 0.00 27.50 7.28 4.95 0.00 30.00 7.28 4.95 0.00 32.50 7.28 4.95 0.00 35.00 7.28 4.95 0.00 37.50 7.28 4.95 0.00 40.00 7.28 4.95 0.00 42.50 7.28 4.95 0.00 45.00 7.28 4.95 0.00 47.50 7.28 4.95 0.00 50.00 7.28 4.95 0.00 52.50 7.28 4.95 0.00 55.00 7.28 4.95 0.00 57.50 7.28 4.95 0.00 60.00 7.28 4.95 0.00 62.50 7.28 4.95 0.00 65.00 7.28 4.95 0.00 67.50 7.28 4.95 0.00 70.00 7.28 4.95 0.00 72.50 7.28 4.95 0.00 75.00 7.28 4.95 0.00 77.50 7.28 4.95 0.00 80.00 7.28 4.95 0.00 82.50 7.28 4.95 0.00 85.00 7.28 4.95 0.00 87.50 7.28 4.95 0.00 90.00 7.28 4.95 0.00 92.50 7.28 4.95 0.00 95.00 7.28 4.95 0.00 97.50 7.28 4.95 0.00 100.00 7.28 4.95 0.00 102.50 7.28 4.95 0.00 105.00 7.28 4.95 0.00 107.50 7.28 4.95 0.00 110.00 7.28 4.95 0.00 112.50 7.28 4.95 0.00 115.00 7.28 4.95 0.00 117.50 7.28 4.95 0.00 120.00 7.28 4.95 0.00 NOAA 24-hr A 10-yr Rainfall=7.28"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 31HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Summary for Pond 5P: BMP 1 Inflow Area = 1.155 ac, 78.35% Impervious, Inflow Depth = 6.57" for 10-yr event Inflow = 11.63 cfs @ 12.11 hrs, Volume= 0.632 af Outflow = 4.11 cfs @ 12.26 hrs, Volume= 0.555 af, Atten= 65%, Lag= 9.1 min Primary = 4.11 cfs @ 12.26 hrs, Volume= 0.555 af Routed to Link 4L : poi 1 combined Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs Peak Elev= 29.76' @ 12.26 hrs Surf.Area= 0.191 ac Storage= 0.325 af Plug-Flow detention time= 182.3 min calculated for 0.555 af (88% of inflow) Center-of-Mass det. time= 133.7 min ( 891.9 - 758.2 ) Volume Invert Avail.Storage Storage Description #1A 27.00' 0.301 af 45.58'W x 182.92'L x 5.92'H Field A 1.133 af Overall - 0.381 af Embedded = 0.752 af x 40.0% Voids #2A 28.00' 0.381 af CMP Arch 71x47 x 45 Inside #1 Effective Size= 71.0"W x 47.0"H => 18.31 sf x 20.00'L = 366.1 cf Overall Size= 71.0"W x 47.0"H x 20.00'L Row Length Adjustment= -7.00' x 18.31 sf x 5 rows 41.58' Header x 18.31 sf x 1 = 761.3 cf Inside 0.682 af Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Primary 28.00'24.0" Round Culvert L= 21.0' RCP, groove end projecting, Ke= 0.200 Inlet / Outlet Invert= 28.00' / 27.80' S= 0.0095 '/' Cc= 0.900 n= 0.010, Flow Area= 3.14 sf #2 Device 1 28.00'6.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Device 1 29.25'2.5' long Sharp-Crested Rectangular Weir 0 End Contraction(s) Primary OutFlow Max=4.07 cfs @ 12.26 hrs HW=29.75' (Free Discharge) 1=Culvert (Passes 4.07 cfs of 12.18 cfs potential flow) 2=Orifice/Grate (Orifice Controls 1.16 cfs @ 5.90 fps) 3=Sharp-Crested Rectangular Weir (Weir Controls 2.91 cfs @ 2.32 fps) NOAA 24-hr A 10-yr Rainfall=7.28"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 32HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Pond 5P: BMP 1 - Chamber Wizard Field A Chamber Model = CMP Arch 71x47 (1/2" Corrugated Pipe Arch, AISI Handbook 1994, Table 2.18) Effective Size= 71.0"W x 47.0"H => 18.31 sf x 20.00'L = 366.1 cf Overall Size= 71.0"W x 47.0"H x 20.00'L Row Length Adjustment= -7.00' x 18.31 sf x 5 rows 71.0" Wide + 36.0" Spacing = 107.0" C-C Row Spacing 9 Chambers/Row x 20.00' Long -7.00' Row Adjustment +5.92' Header x 1 = 178.92' Row Length +24.0" End Stone x 2 = 182.92' Base Length 5 Rows x 71.0" Wide + 36.0" Spacing x 4 + 24.0" Side Stone x 2 = 45.58' Base Width 12.0" Stone Base + 47.0" Chamber Height + 12.0" Stone Cover = 5.92' Field Height 45 Chambers x 366.1 cf -7.00' Row Adjustment x 18.31 sf x 5 Rows + 41.58' Header x 18.31 sf = 16,597.0 cf Chamber Storage 49,332.9 cf Field - 16,597.0 cf Chambers = 32,735.8 cf Stone x 40.0% Voids = 13,094.3 cf Stone Storage Chamber Storage + Stone Storage = 29,691.4 cf = 0.682 af Overall Storage Efficiency = 60.2% Overall System Size = 182.92' x 45.58' x 5.92' 45 Chambers 1,827.1 cy Field 1,212.4 cy Stone NOAA 24-hr A 10-yr Rainfall=7.28"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 33HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Pond 5P: BMP 1 Inflow Primary Hydrograph Time (hours) 12011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=1.155 ac Peak Elev=29.76' Storage=0.325 af 11.63 cfs 4.11 cfs Pond 5P: BMP 1 Primary Stage-Discharge Discharge (cfs) 35302520151050 El e v a t i o n ( f e e t ) 32 31 30 29 28 27 Culvert + Orifice/Grate Sharp-Crested Rectangular Weir NOAA 24-hr A 10-yr Rainfall=7.28"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 34HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Pond 5P: BMP 1 Storage Stage-Area-Storage Storage (acre-feet) 0.650.60.550.50.450.40.350.30.250.20.150.10.050 El e v a t i o n ( f e e t ) 32 31 30 29 28 27 Field A CMP Arch 71x47 NOAA 24-hr A 10-yr Rainfall=7.28"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 35HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Hydrograph for Pond 5P: BMP 1 Time (hours) Inflow (cfs) Storage (acre-feet) Elevation (feet) Primary (cfs) 0.00 0.00 0.000 27.00 0.00 2.50 0.00 0.000 27.00 0.00 5.00 0.04 0.004 27.05 0.00 7.50 0.09 0.016 27.20 0.00 10.00 0.26 0.047 27.61 0.00 12.50 1.94 0.305 29.62 2.96 15.00 0.21 0.183 28.81 0.71 17.50 0.12 0.116 28.33 0.27 20.00 0.08 0.099 28.21 0.12 22.50 0.06 0.094 28.17 0.08 25.00 0.00 0.088 28.12 0.04 27.50 0.00 0.083 28.07 0.01 30.00 0.00 0.081 28.05 0.01 32.50 0.00 0.080 28.04 0.00 35.00 0.00 0.079 28.03 0.00 37.50 0.00 0.078 28.02 0.00 40.00 0.00 0.078 28.02 0.00 42.50 0.00 0.078 28.01 0.00 45.00 0.00 0.077 28.01 0.00 47.50 0.00 0.077 28.01 0.00 50.00 0.00 0.077 28.01 0.00 52.50 0.00 0.077 28.01 0.00 55.00 0.00 0.077 28.01 0.00 57.50 0.00 0.077 28.01 0.00 60.00 0.00 0.077 28.01 0.00 62.50 0.00 0.077 28.01 0.00 65.00 0.00 0.077 28.01 0.00 67.50 0.00 0.077 28.01 0.00 70.00 0.00 0.077 28.00 0.00 72.50 0.00 0.077 28.00 0.00 75.00 0.00 0.077 28.00 0.00 77.50 0.00 0.077 28.00 0.00 80.00 0.00 0.077 28.00 0.00 82.50 0.00 0.077 28.00 0.00 85.00 0.00 0.077 28.00 0.00 87.50 0.00 0.077 28.00 0.00 90.00 0.00 0.077 28.00 0.00 92.50 0.00 0.077 28.00 0.00 95.00 0.00 0.077 28.00 0.00 97.50 0.00 0.077 28.00 0.00 100.00 0.00 0.077 28.00 0.00 102.50 0.00 0.077 28.00 0.00 105.00 0.00 0.077 28.00 0.00 107.50 0.00 0.077 28.00 0.00 110.00 0.00 0.077 28.00 0.00 112.50 0.00 0.077 28.00 0.00 115.00 0.00 0.077 28.00 0.00 117.50 0.00 0.077 28.00 0.00 120.00 0.00 0.077 28.00 0.00 NOAA 24-hr A 10-yr Rainfall=7.28"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 36HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Stage-Discharge for Pond 5P: BMP 1 Elevation (feet) Primary (cfs) 27.00 0.00 27.05 0.00 27.10 0.00 27.15 0.00 27.20 0.00 27.25 0.00 27.30 0.00 27.35 0.00 27.40 0.00 27.45 0.00 27.50 0.00 27.55 0.00 27.60 0.00 27.65 0.00 27.70 0.00 27.75 0.00 27.80 0.00 27.85 0.00 27.90 0.00 27.95 0.00 28.00 0.00 28.05 0.01 28.10 0.03 28.15 0.07 28.20 0.11 28.25 0.17 28.30 0.23 28.35 0.30 28.40 0.36 28.45 0.43 28.50 0.47 28.55 0.52 28.60 0.56 28.65 0.60 28.70 0.63 28.75 0.67 28.80 0.70 28.85 0.73 28.90 0.76 28.95 0.79 29.00 0.82 29.05 0.85 29.10 0.87 29.15 0.90 29.20 0.92 29.25 0.95 29.30 1.06 29.35 1.25 29.40 1.49 29.45 1.77 29.50 2.08 29.55 2.42 29.60 2.79 Elevation (feet) Primary (cfs) 29.65 3.19 29.70 3.61 29.75 4.05 29.80 4.51 29.85 5.00 29.90 5.50 29.95 6.02 30.00 6.56 30.05 7.12 30.10 7.69 30.15 8.28 30.20 8.89 30.25 9.51 30.30 10.15 30.35 10.80 30.40 11.47 30.45 12.15 30.50 12.84 30.55 13.55 30.60 14.27 30.65 15.01 30.70 15.75 30.75 16.51 30.80 17.29 30.85 18.07 30.90 18.87 30.95 19.67 31.00 20.49 31.05 21.32 31.10 22.17 31.15 23.02 31.20 23.88 31.25 24.76 31.30 25.65 31.35 26.54 31.40 27.40 31.45 27.82 31.50 28.24 31.55 28.65 31.60 29.06 31.65 29.46 31.70 29.86 31.75 30.25 31.80 30.63 31.85 31.01 31.90 31.39 31.95 31.76 32.00 32.13 32.05 32.49 32.10 32.85 32.15 33.20 32.20 33.55 32.25 33.90 Elevation (feet) Primary (cfs) 32.30 34.25 32.35 34.59 32.40 34.87 32.45 35.12 32.50 35.37 32.55 35.63 32.60 35.88 32.65 36.12 32.70 36.37 32.75 36.62 32.80 36.86 32.85 37.10 32.90 37.34 NOAA 24-hr A 10-yr Rainfall=7.28"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 37HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond 5P: BMP 1 Elevation (feet) Storage (acre-feet) 27.00 0.000 27.05 0.004 27.10 0.008 27.15 0.011 27.20 0.015 27.25 0.019 27.30 0.023 27.35 0.027 27.40 0.031 27.45 0.034 27.50 0.038 27.55 0.042 27.60 0.046 27.65 0.050 27.70 0.054 27.75 0.057 27.80 0.061 27.85 0.065 27.90 0.069 27.95 0.073 28.00 0.077 28.05 0.081 28.10 0.086 28.15 0.092 28.20 0.098 28.25 0.105 28.30 0.111 28.35 0.118 28.40 0.125 28.45 0.132 28.50 0.139 28.55 0.146 28.60 0.153 28.65 0.160 28.70 0.168 28.75 0.175 28.80 0.182 28.85 0.190 28.90 0.197 28.95 0.205 29.00 0.212 29.05 0.220 29.10 0.227 29.15 0.235 29.20 0.242 29.25 0.250 29.30 0.257 29.35 0.265 29.40 0.272 29.45 0.280 29.50 0.287 29.55 0.295 29.60 0.302 Elevation (feet) Storage (acre-feet) 29.65 0.310 29.70 0.317 29.75 0.324 29.80 0.332 29.85 0.339 29.90 0.347 29.95 0.354 30.00 0.361 30.05 0.369 30.10 0.376 30.15 0.383 30.20 0.390 30.25 0.398 30.30 0.405 30.35 0.412 30.40 0.419 30.45 0.426 30.50 0.433 30.55 0.440 30.60 0.447 30.65 0.454 30.70 0.461 30.75 0.468 30.80 0.474 30.85 0.481 30.90 0.488 30.95 0.494 31.00 0.501 31.05 0.507 31.10 0.514 31.15 0.520 31.20 0.526 31.25 0.533 31.30 0.539 31.35 0.545 31.40 0.551 31.45 0.557 31.50 0.562 31.55 0.568 31.60 0.574 31.65 0.579 31.70 0.584 31.75 0.590 31.80 0.595 31.85 0.599 31.90 0.604 31.95 0.608 32.00 0.611 32.05 0.615 32.10 0.619 32.15 0.623 32.20 0.627 32.25 0.631 Elevation (feet) Storage (acre-feet) 32.30 0.634 32.35 0.638 32.40 0.642 32.45 0.646 32.50 0.650 32.55 0.654 32.60 0.657 32.65 0.661 32.70 0.665 32.75 0.669 32.80 0.673 32.85 0.677 32.90 0.680 NOAA 24-hr A 10-yr Rainfall=7.28"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 38HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Summary for Link 4L: poi 1 combined Inflow Area = 1.705 ac, 53.08% Impervious, Inflow Depth = 5.51" for 10-yr event Inflow = 7.58 cfs @ 12.21 hrs, Volume= 0.782 af Primary = 7.58 cfs @ 12.21 hrs, Volume= 0.782 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs Link 4L: poi 1 combined Inflow Primary Hydrograph Time (hours) 12011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 8 7 6 5 4 3 2 1 0 Inflow Area=1.705 ac 7.58 cfs7.58 cfs NOAA 24-hr A 10-yr Rainfall=7.28"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 39HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Hydrograph for Link 4L: poi 1 combined Time (hours) Inflow (cfs) Elevation (feet) Primary (cfs) 0.00 0.00 0.00 0.00 2.50 0.00 0.00 0.00 5.00 0.00 0.00 0.00 7.50 0.00 0.00 0.00 10.00 0.04 0.00 0.04 12.50 3.94 0.00 3.94 15.00 0.80 0.00 0.80 17.50 0.33 0.00 0.33 20.00 0.16 0.00 0.16 22.50 0.11 0.00 0.11 25.00 0.04 0.00 0.04 27.50 0.01 0.00 0.01 30.00 0.01 0.00 0.01 32.50 0.00 0.00 0.00 35.00 0.00 0.00 0.00 37.50 0.00 0.00 0.00 40.00 0.00 0.00 0.00 42.50 0.00 0.00 0.00 45.00 0.00 0.00 0.00 47.50 0.00 0.00 0.00 50.00 0.00 0.00 0.00 52.50 0.00 0.00 0.00 55.00 0.00 0.00 0.00 57.50 0.00 0.00 0.00 60.00 0.00 0.00 0.00 62.50 0.00 0.00 0.00 65.00 0.00 0.00 0.00 67.50 0.00 0.00 0.00 70.00 0.00 0.00 0.00 72.50 0.00 0.00 0.00 75.00 0.00 0.00 0.00 77.50 0.00 0.00 0.00 80.00 0.00 0.00 0.00 82.50 0.00 0.00 0.00 85.00 0.00 0.00 0.00 87.50 0.00 0.00 0.00 90.00 0.00 0.00 0.00 92.50 0.00 0.00 0.00 95.00 0.00 0.00 0.00 97.50 0.00 0.00 0.00 100.00 0.00 0.00 0.00 102.50 0.00 0.00 0.00 105.00 0.00 0.00 0.00 107.50 0.00 0.00 0.00 110.00 0.00 0.00 0.00 112.50 0.00 0.00 0.00 115.00 0.00 0.00 0.00 117.50 0.00 0.00 0.00 120.00 0.00 0.00 0.00 NOAA 24-hr A 25-yr Rainfall=9.13"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 40HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Time span=0.00-120.00 hrs, dt=0.05 hrs, 2401 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=1.710 ac 1.46% Impervious Runoff Depth=6.69"Subcatchment 1S: pre poi 1 Flow Length=442' Tc=18.7 min CN=80 Runoff=12.45 cfs 0.954 af Runoff Area=1.155 ac 78.35% Impervious Runoff Depth=8.41"Subcatchment 2S: poi 1 to bmp Tc=5.0 min CN=94 Runoff=14.69 cfs 0.809 af Runoff Area=0.550 ac 0.00% Impervious Runoff Depth=6.69"Subcatchment 3S: poi 1 bypass Tc=10.0 min CN=80 Runoff=5.15 cfs 0.307 af Peak Elev=30.08' Storage=0.373 af Inflow=14.69 cfs 0.809 afPond 5P: BMP 1 Outflow=7.46 cfs 0.732 af Inflow=12.37 cfs 1.039 afLink 4L: poi 1 combined Primary=12.37 cfs 1.039 af Total Runoff Area = 3.415 ac Runoff Volume = 2.069 af Average Runoff Depth = 7.27" 72.77% Pervious = 2.485 ac 27.23% Impervious = 0.930 ac NOAA 24-hr A 25-yr Rainfall=9.13"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 41HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: pre poi 1 Runoff = 12.45 cfs @ 12.27 hrs, Volume= 0.954 af, Depth= 6.69" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs NOAA 24-hr A 25-yr Rainfall=9.13" Area (ac) CN Description 1.685 80 >75% Grass cover, Good, HSG D * 0.025 98 ex driveway 1.710 80 Weighted Average 1.685 98.54% Pervious Area 0.025 1.46% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13.1 100 0.0100 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.12" 5.3 242 0.0120 0.77 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 0.3 100 0.0200 5.79 115.77 Channel Flow, Area= 20.0 sf Perim= 35.0' r= 0.57' n= 0.025 Earth, clean & winding 18.7 442 Total Subcatchment 1S: pre poi 1 Runoff Hydrograph Time (hours) 12011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 13 12 11 10 9 8 7 6 5 4 3 2 1 0 NOAA 24-hr A 25-yr Rainfall=9.13" Runoff Area=1.710 ac Runoff Volume=0.954 af Runoff Depth=6.69" Flow Length=442' Tc=18.7 min CN=80 12.45 cfs NOAA 24-hr A 25-yr Rainfall=9.13"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 42HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Hydrograph for Subcatchment 1S: pre poi 1 Time (hours) Precip. (inches) Excess (inches) Runoff (cfs) 0.00 0.00 0.00 0.00 2.50 0.17 0.00 0.00 5.00 0.39 0.00 0.00 7.50 0.69 0.01 0.03 10.00 1.25 0.17 0.20 12.50 6.86 4.56 6.74 15.00 8.16 5.78 0.41 17.50 8.58 6.17 0.22 20.00 8.84 6.41 0.15 22.50 9.03 6.60 0.12 25.00 9.13 6.69 0.00 27.50 9.13 6.69 0.00 30.00 9.13 6.69 0.00 32.50 9.13 6.69 0.00 35.00 9.13 6.69 0.00 37.50 9.13 6.69 0.00 40.00 9.13 6.69 0.00 42.50 9.13 6.69 0.00 45.00 9.13 6.69 0.00 47.50 9.13 6.69 0.00 50.00 9.13 6.69 0.00 52.50 9.13 6.69 0.00 55.00 9.13 6.69 0.00 57.50 9.13 6.69 0.00 60.00 9.13 6.69 0.00 62.50 9.13 6.69 0.00 65.00 9.13 6.69 0.00 67.50 9.13 6.69 0.00 70.00 9.13 6.69 0.00 72.50 9.13 6.69 0.00 75.00 9.13 6.69 0.00 77.50 9.13 6.69 0.00 80.00 9.13 6.69 0.00 82.50 9.13 6.69 0.00 85.00 9.13 6.69 0.00 87.50 9.13 6.69 0.00 90.00 9.13 6.69 0.00 92.50 9.13 6.69 0.00 95.00 9.13 6.69 0.00 97.50 9.13 6.69 0.00 100.00 9.13 6.69 0.00 102.50 9.13 6.69 0.00 105.00 9.13 6.69 0.00 107.50 9.13 6.69 0.00 110.00 9.13 6.69 0.00 112.50 9.13 6.69 0.00 115.00 9.13 6.69 0.00 117.50 9.13 6.69 0.00 120.00 9.13 6.69 0.00 NOAA 24-hr A 25-yr Rainfall=9.13"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 43HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: poi 1 to bmp [49] Hint: Tc<2dt may require smaller dt Runoff = 14.69 cfs @ 12.11 hrs, Volume= 0.809 af, Depth= 8.41" Routed to Pond 5P : BMP 1 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs NOAA 24-hr A 25-yr Rainfall=9.13" Area (ac) CN Description 0.880 98 Paved parking, HSG B * 0.025 98 ex driveway 0.250 80 >75% Grass cover, Good, HSG D 1.155 94 Weighted Average 0.250 21.65% Pervious Area 0.905 78.35% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 2S: poi 1 to bmp Runoff Hydrograph Time (hours) 12011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 NOAA 24-hr A 25-yr Rainfall=9.13" Runoff Area=1.155 ac Runoff Volume=0.809 af Runoff Depth=8.41" Tc=5.0 min CN=94 14.69 cfs NOAA 24-hr A 25-yr Rainfall=9.13"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 44HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Hydrograph for Subcatchment 2S: poi 1 to bmp Time (hours) Precip. (inches) Excess (inches) Runoff (cfs) 0.00 0.00 0.00 0.00 2.50 0.17 0.00 0.01 5.00 0.39 0.08 0.06 7.50 0.69 0.26 0.13 10.00 1.25 0.72 0.35 12.50 6.86 6.15 2.44 15.00 8.16 7.44 0.26 17.50 8.58 7.86 0.15 20.00 8.84 8.11 0.11 22.50 9.03 8.31 0.08 25.00 9.13 8.41 0.00 27.50 9.13 8.41 0.00 30.00 9.13 8.41 0.00 32.50 9.13 8.41 0.00 35.00 9.13 8.41 0.00 37.50 9.13 8.41 0.00 40.00 9.13 8.41 0.00 42.50 9.13 8.41 0.00 45.00 9.13 8.41 0.00 47.50 9.13 8.41 0.00 50.00 9.13 8.41 0.00 52.50 9.13 8.41 0.00 55.00 9.13 8.41 0.00 57.50 9.13 8.41 0.00 60.00 9.13 8.41 0.00 62.50 9.13 8.41 0.00 65.00 9.13 8.41 0.00 67.50 9.13 8.41 0.00 70.00 9.13 8.41 0.00 72.50 9.13 8.41 0.00 75.00 9.13 8.41 0.00 77.50 9.13 8.41 0.00 80.00 9.13 8.41 0.00 82.50 9.13 8.41 0.00 85.00 9.13 8.41 0.00 87.50 9.13 8.41 0.00 90.00 9.13 8.41 0.00 92.50 9.13 8.41 0.00 95.00 9.13 8.41 0.00 97.50 9.13 8.41 0.00 100.00 9.13 8.41 0.00 102.50 9.13 8.41 0.00 105.00 9.13 8.41 0.00 107.50 9.13 8.41 0.00 110.00 9.13 8.41 0.00 112.50 9.13 8.41 0.00 115.00 9.13 8.41 0.00 117.50 9.13 8.41 0.00 120.00 9.13 8.41 0.00 NOAA 24-hr A 25-yr Rainfall=9.13"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 45HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Summary for Subcatchment 3S: poi 1 bypass Runoff = 5.15 cfs @ 12.17 hrs, Volume= 0.307 af, Depth= 6.69" Routed to Link 4L : poi 1 combined Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs NOAA 24-hr A 25-yr Rainfall=9.13" Area (ac) CN Description 0.550 80 >75% Grass cover, Good, HSG D 0.550 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment 3S: poi 1 bypass Runoff Hydrograph Time (hours) 12011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 5 4 3 2 1 0 NOAA 24-hr A 25-yr Rainfall=9.13" Runoff Area=0.550 ac Runoff Volume=0.307 af Runoff Depth=6.69" Tc=10.0 min CN=80 5.15 cfs NOAA 24-hr A 25-yr Rainfall=9.13"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 46HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Hydrograph for Subcatchment 3S: poi 1 bypass Time (hours) Precip. (inches) Excess (inches) Runoff (cfs) 0.00 0.00 0.00 0.00 2.50 0.17 0.00 0.00 5.00 0.39 0.00 0.00 7.50 0.69 0.01 0.01 10.00 1.25 0.17 0.07 12.50 6.86 4.56 1.27 15.00 8.16 5.78 0.12 17.50 8.58 6.17 0.07 20.00 8.84 6.41 0.05 22.50 9.03 6.60 0.04 25.00 9.13 6.69 0.00 27.50 9.13 6.69 0.00 30.00 9.13 6.69 0.00 32.50 9.13 6.69 0.00 35.00 9.13 6.69 0.00 37.50 9.13 6.69 0.00 40.00 9.13 6.69 0.00 42.50 9.13 6.69 0.00 45.00 9.13 6.69 0.00 47.50 9.13 6.69 0.00 50.00 9.13 6.69 0.00 52.50 9.13 6.69 0.00 55.00 9.13 6.69 0.00 57.50 9.13 6.69 0.00 60.00 9.13 6.69 0.00 62.50 9.13 6.69 0.00 65.00 9.13 6.69 0.00 67.50 9.13 6.69 0.00 70.00 9.13 6.69 0.00 72.50 9.13 6.69 0.00 75.00 9.13 6.69 0.00 77.50 9.13 6.69 0.00 80.00 9.13 6.69 0.00 82.50 9.13 6.69 0.00 85.00 9.13 6.69 0.00 87.50 9.13 6.69 0.00 90.00 9.13 6.69 0.00 92.50 9.13 6.69 0.00 95.00 9.13 6.69 0.00 97.50 9.13 6.69 0.00 100.00 9.13 6.69 0.00 102.50 9.13 6.69 0.00 105.00 9.13 6.69 0.00 107.50 9.13 6.69 0.00 110.00 9.13 6.69 0.00 112.50 9.13 6.69 0.00 115.00 9.13 6.69 0.00 117.50 9.13 6.69 0.00 120.00 9.13 6.69 0.00 NOAA 24-hr A 25-yr Rainfall=9.13"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 47HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Summary for Pond 5P: BMP 1 Inflow Area = 1.155 ac, 78.35% Impervious, Inflow Depth = 8.41" for 25-yr event Inflow = 14.69 cfs @ 12.11 hrs, Volume= 0.809 af Outflow = 7.46 cfs @ 12.22 hrs, Volume= 0.732 af, Atten= 49%, Lag= 6.3 min Primary = 7.46 cfs @ 12.22 hrs, Volume= 0.732 af Routed to Link 4L : poi 1 combined Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs Peak Elev= 30.08' @ 12.22 hrs Surf.Area= 0.191 ac Storage= 0.373 af Plug-Flow detention time= 160.1 min calculated for 0.732 af (91% of inflow) Center-of-Mass det. time= 117.8 min ( 871.7 - 753.9 ) Volume Invert Avail.Storage Storage Description #1A 27.00' 0.301 af 45.58'W x 182.92'L x 5.92'H Field A 1.133 af Overall - 0.381 af Embedded = 0.752 af x 40.0% Voids #2A 28.00' 0.381 af CMP Arch 71x47 x 45 Inside #1 Effective Size= 71.0"W x 47.0"H => 18.31 sf x 20.00'L = 366.1 cf Overall Size= 71.0"W x 47.0"H x 20.00'L Row Length Adjustment= -7.00' x 18.31 sf x 5 rows 41.58' Header x 18.31 sf x 1 = 761.3 cf Inside 0.682 af Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Primary 28.00'24.0" Round Culvert L= 21.0' RCP, groove end projecting, Ke= 0.200 Inlet / Outlet Invert= 28.00' / 27.80' S= 0.0095 '/' Cc= 0.900 n= 0.010, Flow Area= 3.14 sf #2 Device 1 28.00'6.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Device 1 29.25'2.5' long Sharp-Crested Rectangular Weir 0 End Contraction(s) Primary OutFlow Max=7.31 cfs @ 12.22 hrs HW=30.07' (Free Discharge) 1=Culvert (Passes 7.31 cfs of 15.45 cfs potential flow) 2=Orifice/Grate (Orifice Controls 1.27 cfs @ 6.49 fps) 3=Sharp-Crested Rectangular Weir (Weir Controls 6.03 cfs @ 2.95 fps) NOAA 24-hr A 25-yr Rainfall=9.13"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 48HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Pond 5P: BMP 1 - Chamber Wizard Field A Chamber Model = CMP Arch 71x47 (1/2" Corrugated Pipe Arch, AISI Handbook 1994, Table 2.18) Effective Size= 71.0"W x 47.0"H => 18.31 sf x 20.00'L = 366.1 cf Overall Size= 71.0"W x 47.0"H x 20.00'L Row Length Adjustment= -7.00' x 18.31 sf x 5 rows 71.0" Wide + 36.0" Spacing = 107.0" C-C Row Spacing 9 Chambers/Row x 20.00' Long -7.00' Row Adjustment +5.92' Header x 1 = 178.92' Row Length +24.0" End Stone x 2 = 182.92' Base Length 5 Rows x 71.0" Wide + 36.0" Spacing x 4 + 24.0" Side Stone x 2 = 45.58' Base Width 12.0" Stone Base + 47.0" Chamber Height + 12.0" Stone Cover = 5.92' Field Height 45 Chambers x 366.1 cf -7.00' Row Adjustment x 18.31 sf x 5 Rows + 41.58' Header x 18.31 sf = 16,597.0 cf Chamber Storage 49,332.9 cf Field - 16,597.0 cf Chambers = 32,735.8 cf Stone x 40.0% Voids = 13,094.3 cf Stone Storage Chamber Storage + Stone Storage = 29,691.4 cf = 0.682 af Overall Storage Efficiency = 60.2% Overall System Size = 182.92' x 45.58' x 5.92' 45 Chambers 1,827.1 cy Field 1,212.4 cy Stone NOAA 24-hr A 25-yr Rainfall=9.13"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 49HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Pond 5P: BMP 1 Inflow Primary Hydrograph Time (hours) 12011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=1.155 ac Peak Elev=30.08' Storage=0.373 af 14.69 cfs 7.46 cfs Pond 5P: BMP 1 Primary Stage-Discharge Discharge (cfs) 35302520151050 El e v a t i o n ( f e e t ) 32 31 30 29 28 27 Culvert + Orifice/Grate Sharp-Crested Rectangular Weir NOAA 24-hr A 25-yr Rainfall=9.13"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 50HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Pond 5P: BMP 1 Storage Stage-Area-Storage Storage (acre-feet) 0.650.60.550.50.450.40.350.30.250.20.150.10.050 El e v a t i o n ( f e e t ) 32 31 30 29 28 27 Field A CMP Arch 71x47 NOAA 24-hr A 25-yr Rainfall=9.13"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 51HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Hydrograph for Pond 5P: BMP 1 Time (hours) Inflow (cfs) Storage (acre-feet) Elevation (feet) Primary (cfs) 0.00 0.00 0.000 27.00 0.00 2.50 0.01 0.000 27.00 0.00 5.00 0.06 0.007 27.09 0.00 7.50 0.13 0.025 27.32 0.00 10.00 0.35 0.067 27.87 0.00 12.50 2.44 0.324 29.75 4.05 15.00 0.26 0.195 28.89 0.75 17.50 0.15 0.123 28.38 0.34 20.00 0.11 0.102 28.23 0.15 22.50 0.08 0.097 28.19 0.10 25.00 0.00 0.090 28.13 0.05 27.50 0.00 0.084 28.07 0.02 30.00 0.00 0.081 28.05 0.01 32.50 0.00 0.080 28.04 0.00 35.00 0.00 0.079 28.03 0.00 37.50 0.00 0.078 28.02 0.00 40.00 0.00 0.078 28.02 0.00 42.50 0.00 0.078 28.01 0.00 45.00 0.00 0.078 28.01 0.00 47.50 0.00 0.077 28.01 0.00 50.00 0.00 0.077 28.01 0.00 52.50 0.00 0.077 28.01 0.00 55.00 0.00 0.077 28.01 0.00 57.50 0.00 0.077 28.01 0.00 60.00 0.00 0.077 28.01 0.00 62.50 0.00 0.077 28.01 0.00 65.00 0.00 0.077 28.01 0.00 67.50 0.00 0.077 28.01 0.00 70.00 0.00 0.077 28.00 0.00 72.50 0.00 0.077 28.00 0.00 75.00 0.00 0.077 28.00 0.00 77.50 0.00 0.077 28.00 0.00 80.00 0.00 0.077 28.00 0.00 82.50 0.00 0.077 28.00 0.00 85.00 0.00 0.077 28.00 0.00 87.50 0.00 0.077 28.00 0.00 90.00 0.00 0.077 28.00 0.00 92.50 0.00 0.077 28.00 0.00 95.00 0.00 0.077 28.00 0.00 97.50 0.00 0.077 28.00 0.00 100.00 0.00 0.077 28.00 0.00 102.50 0.00 0.077 28.00 0.00 105.00 0.00 0.077 28.00 0.00 107.50 0.00 0.077 28.00 0.00 110.00 0.00 0.077 28.00 0.00 112.50 0.00 0.077 28.00 0.00 115.00 0.00 0.077 28.00 0.00 117.50 0.00 0.077 28.00 0.00 120.00 0.00 0.077 28.00 0.00 NOAA 24-hr A 25-yr Rainfall=9.13"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 52HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Stage-Discharge for Pond 5P: BMP 1 Elevation (feet) Primary (cfs) 27.00 0.00 27.05 0.00 27.10 0.00 27.15 0.00 27.20 0.00 27.25 0.00 27.30 0.00 27.35 0.00 27.40 0.00 27.45 0.00 27.50 0.00 27.55 0.00 27.60 0.00 27.65 0.00 27.70 0.00 27.75 0.00 27.80 0.00 27.85 0.00 27.90 0.00 27.95 0.00 28.00 0.00 28.05 0.01 28.10 0.03 28.15 0.07 28.20 0.11 28.25 0.17 28.30 0.23 28.35 0.30 28.40 0.36 28.45 0.43 28.50 0.47 28.55 0.52 28.60 0.56 28.65 0.60 28.70 0.63 28.75 0.67 28.80 0.70 28.85 0.73 28.90 0.76 28.95 0.79 29.00 0.82 29.05 0.85 29.10 0.87 29.15 0.90 29.20 0.92 29.25 0.95 29.30 1.06 29.35 1.25 29.40 1.49 29.45 1.77 29.50 2.08 29.55 2.42 29.60 2.79 Elevation (feet) Primary (cfs) 29.65 3.19 29.70 3.61 29.75 4.05 29.80 4.51 29.85 5.00 29.90 5.50 29.95 6.02 30.00 6.56 30.05 7.12 30.10 7.69 30.15 8.28 30.20 8.89 30.25 9.51 30.30 10.15 30.35 10.80 30.40 11.47 30.45 12.15 30.50 12.84 30.55 13.55 30.60 14.27 30.65 15.01 30.70 15.75 30.75 16.51 30.80 17.29 30.85 18.07 30.90 18.87 30.95 19.67 31.00 20.49 31.05 21.32 31.10 22.17 31.15 23.02 31.20 23.88 31.25 24.76 31.30 25.65 31.35 26.54 31.40 27.40 31.45 27.82 31.50 28.24 31.55 28.65 31.60 29.06 31.65 29.46 31.70 29.86 31.75 30.25 31.80 30.63 31.85 31.01 31.90 31.39 31.95 31.76 32.00 32.13 32.05 32.49 32.10 32.85 32.15 33.20 32.20 33.55 32.25 33.90 Elevation (feet) Primary (cfs) 32.30 34.25 32.35 34.59 32.40 34.87 32.45 35.12 32.50 35.37 32.55 35.63 32.60 35.88 32.65 36.12 32.70 36.37 32.75 36.62 32.80 36.86 32.85 37.10 32.90 37.34 NOAA 24-hr A 25-yr Rainfall=9.13"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 53HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond 5P: BMP 1 Elevation (feet) Storage (acre-feet) 27.00 0.000 27.05 0.004 27.10 0.008 27.15 0.011 27.20 0.015 27.25 0.019 27.30 0.023 27.35 0.027 27.40 0.031 27.45 0.034 27.50 0.038 27.55 0.042 27.60 0.046 27.65 0.050 27.70 0.054 27.75 0.057 27.80 0.061 27.85 0.065 27.90 0.069 27.95 0.073 28.00 0.077 28.05 0.081 28.10 0.086 28.15 0.092 28.20 0.098 28.25 0.105 28.30 0.111 28.35 0.118 28.40 0.125 28.45 0.132 28.50 0.139 28.55 0.146 28.60 0.153 28.65 0.160 28.70 0.168 28.75 0.175 28.80 0.182 28.85 0.190 28.90 0.197 28.95 0.205 29.00 0.212 29.05 0.220 29.10 0.227 29.15 0.235 29.20 0.242 29.25 0.250 29.30 0.257 29.35 0.265 29.40 0.272 29.45 0.280 29.50 0.287 29.55 0.295 29.60 0.302 Elevation (feet) Storage (acre-feet) 29.65 0.310 29.70 0.317 29.75 0.324 29.80 0.332 29.85 0.339 29.90 0.347 29.95 0.354 30.00 0.361 30.05 0.369 30.10 0.376 30.15 0.383 30.20 0.390 30.25 0.398 30.30 0.405 30.35 0.412 30.40 0.419 30.45 0.426 30.50 0.433 30.55 0.440 30.60 0.447 30.65 0.454 30.70 0.461 30.75 0.468 30.80 0.474 30.85 0.481 30.90 0.488 30.95 0.494 31.00 0.501 31.05 0.507 31.10 0.514 31.15 0.520 31.20 0.526 31.25 0.533 31.30 0.539 31.35 0.545 31.40 0.551 31.45 0.557 31.50 0.562 31.55 0.568 31.60 0.574 31.65 0.579 31.70 0.584 31.75 0.590 31.80 0.595 31.85 0.599 31.90 0.604 31.95 0.608 32.00 0.611 32.05 0.615 32.10 0.619 32.15 0.623 32.20 0.627 32.25 0.631 Elevation (feet) Storage (acre-feet) 32.30 0.634 32.35 0.638 32.40 0.642 32.45 0.646 32.50 0.650 32.55 0.654 32.60 0.657 32.65 0.661 32.70 0.665 32.75 0.669 32.80 0.673 32.85 0.677 32.90 0.680 NOAA 24-hr A 25-yr Rainfall=9.13"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 54HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Summary for Link 4L: poi 1 combined Inflow Area = 1.705 ac, 53.08% Impervious, Inflow Depth = 7.31" for 25-yr event Inflow = 12.37 cfs @ 12.20 hrs, Volume= 1.039 af Primary = 12.37 cfs @ 12.20 hrs, Volume= 1.039 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs Link 4L: poi 1 combined Inflow Primary Hydrograph Time (hours) 12011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=1.705 ac 12.37 cfs12.37 cfs NOAA 24-hr A 25-yr Rainfall=9.13"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 55HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Hydrograph for Link 4L: poi 1 combined Time (hours) Inflow (cfs) Elevation (feet) Primary (cfs) 0.00 0.00 0.00 0.00 2.50 0.00 0.00 0.00 5.00 0.00 0.00 0.00 7.50 0.01 0.00 0.01 10.00 0.07 0.00 0.07 12.50 5.32 0.00 5.32 15.00 0.88 0.00 0.88 17.50 0.41 0.00 0.41 20.00 0.19 0.00 0.19 22.50 0.14 0.00 0.14 25.00 0.05 0.00 0.05 27.50 0.02 0.00 0.02 30.00 0.01 0.00 0.01 32.50 0.00 0.00 0.00 35.00 0.00 0.00 0.00 37.50 0.00 0.00 0.00 40.00 0.00 0.00 0.00 42.50 0.00 0.00 0.00 45.00 0.00 0.00 0.00 47.50 0.00 0.00 0.00 50.00 0.00 0.00 0.00 52.50 0.00 0.00 0.00 55.00 0.00 0.00 0.00 57.50 0.00 0.00 0.00 60.00 0.00 0.00 0.00 62.50 0.00 0.00 0.00 65.00 0.00 0.00 0.00 67.50 0.00 0.00 0.00 70.00 0.00 0.00 0.00 72.50 0.00 0.00 0.00 75.00 0.00 0.00 0.00 77.50 0.00 0.00 0.00 80.00 0.00 0.00 0.00 82.50 0.00 0.00 0.00 85.00 0.00 0.00 0.00 87.50 0.00 0.00 0.00 90.00 0.00 0.00 0.00 92.50 0.00 0.00 0.00 95.00 0.00 0.00 0.00 97.50 0.00 0.00 0.00 100.00 0.00 0.00 0.00 102.50 0.00 0.00 0.00 105.00 0.00 0.00 0.00 107.50 0.00 0.00 0.00 110.00 0.00 0.00 0.00 112.50 0.00 0.00 0.00 115.00 0.00 0.00 0.00 117.50 0.00 0.00 0.00 120.00 0.00 0.00 0.00 NOAA 24-hr A 100-yr Rainfall=12.70"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 56HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Time span=0.00-120.00 hrs, dt=0.05 hrs, 2401 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=1.710 ac 1.46% Impervious Runoff Depth=10.13"Subcatchment 1S: pre poi 1 Flow Length=442' Tc=18.7 min CN=80 Runoff=18.47 cfs 1.443 af Runoff Area=1.155 ac 78.35% Impervious Runoff Depth=11.96"Subcatchment 2S: poi 1 to bmp Tc=5.0 min CN=94 Runoff=20.58 cfs 1.152 af Runoff Area=0.550 ac 0.00% Impervious Runoff Depth=10.13"Subcatchment 3S: poi 1 bypass Tc=10.0 min CN=80 Runoff=7.62 cfs 0.464 af Peak Elev=30.54' Storage=0.438 af Inflow=20.58 cfs 1.152 afPond 5P: BMP 1 Outflow=13.38 cfs 1.075 af Inflow=20.91 cfs 1.539 afLink 4L: poi 1 combined Primary=20.91 cfs 1.539 af Total Runoff Area = 3.415 ac Runoff Volume = 3.059 af Average Runoff Depth = 10.75" 72.77% Pervious = 2.485 ac 27.23% Impervious = 0.930 ac NOAA 24-hr A 100-yr Rainfall=12.70"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 59HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: poi 1 to bmp [49] Hint: Tc<2dt may require smaller dt Runoff = 20.58 cfs @ 12.11 hrs, Volume= 1.152 af, Depth=11.96" Routed to Pond 5P : BMP 1 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs NOAA 24-hr A 100-yr Rainfall=12.70" Area (ac) CN Description 0.880 98 Paved parking, HSG B * 0.025 98 ex driveway 0.250 80 >75% Grass cover, Good, HSG D 1.155 94 Weighted Average 0.250 21.65% Pervious Area 0.905 78.35% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 2S: poi 1 to bmp Runoff Hydrograph Time (hours) 12011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 NOAA 24-hr A 100-yr Rainfall=12.70" Runoff Area=1.155 ac Runoff Volume=1.152 af Runoff Depth=11.96" Tc=5.0 min CN=94 20.58 cfs NOAA 24-hr A 100-yr Rainfall=12.70"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 60HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Hydrograph for Subcatchment 2S: poi 1 to bmp Time (hours) Precip. (inches) Excess (inches) Runoff (cfs) 0.00 0.00 0.00 0.00 2.50 0.23 0.02 0.03 5.00 0.54 0.16 0.10 7.50 0.96 0.47 0.20 10.00 1.74 1.15 0.51 12.50 9.54 8.81 3.41 15.00 11.36 10.62 0.36 17.50 11.94 11.20 0.21 20.00 12.29 11.56 0.15 22.50 12.57 11.83 0.11 25.00 12.70 11.96 0.00 27.50 12.70 11.96 0.00 30.00 12.70 11.96 0.00 32.50 12.70 11.96 0.00 35.00 12.70 11.96 0.00 37.50 12.70 11.96 0.00 40.00 12.70 11.96 0.00 42.50 12.70 11.96 0.00 45.00 12.70 11.96 0.00 47.50 12.70 11.96 0.00 50.00 12.70 11.96 0.00 52.50 12.70 11.96 0.00 55.00 12.70 11.96 0.00 57.50 12.70 11.96 0.00 60.00 12.70 11.96 0.00 62.50 12.70 11.96 0.00 65.00 12.70 11.96 0.00 67.50 12.70 11.96 0.00 70.00 12.70 11.96 0.00 72.50 12.70 11.96 0.00 75.00 12.70 11.96 0.00 77.50 12.70 11.96 0.00 80.00 12.70 11.96 0.00 82.50 12.70 11.96 0.00 85.00 12.70 11.96 0.00 87.50 12.70 11.96 0.00 90.00 12.70 11.96 0.00 92.50 12.70 11.96 0.00 95.00 12.70 11.96 0.00 97.50 12.70 11.96 0.00 100.00 12.70 11.96 0.00 102.50 12.70 11.96 0.00 105.00 12.70 11.96 0.00 107.50 12.70 11.96 0.00 110.00 12.70 11.96 0.00 112.50 12.70 11.96 0.00 115.00 12.70 11.96 0.00 117.50 12.70 11.96 0.00 120.00 12.70 11.96 0.00 NOAA 24-hr A 100-yr Rainfall=12.70"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 63HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Summary for Pond 5P: BMP 1 Inflow Area = 1.155 ac, 78.35% Impervious, Inflow Depth = 11.96" for 100-yr event Inflow = 20.58 cfs @ 12.11 hrs, Volume= 1.152 af Outflow = 13.38 cfs @ 12.19 hrs, Volume= 1.075 af, Atten= 35%, Lag= 4.7 min Primary = 13.38 cfs @ 12.19 hrs, Volume= 1.075 af Routed to Link 4L : poi 1 combined Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs Peak Elev= 30.54' @ 12.19 hrs Surf.Area= 0.191 ac Storage= 0.438 af Plug-Flow detention time= 131.9 min calculated for 1.074 af (93% of inflow) Center-of-Mass det. time= 99.8 min ( 848.2 - 748.4 ) Volume Invert Avail.Storage Storage Description #1A 27.00' 0.301 af 45.58'W x 182.92'L x 5.92'H Field A 1.133 af Overall - 0.381 af Embedded = 0.752 af x 40.0% Voids #2A 28.00' 0.381 af CMP Arch 71x47 x 45 Inside #1 Effective Size= 71.0"W x 47.0"H => 18.31 sf x 20.00'L = 366.1 cf Overall Size= 71.0"W x 47.0"H x 20.00'L Row Length Adjustment= -7.00' x 18.31 sf x 5 rows 41.58' Header x 18.31 sf x 1 = 761.3 cf Inside 0.682 af Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Primary 28.00'24.0" Round Culvert L= 21.0' RCP, groove end projecting, Ke= 0.200 Inlet / Outlet Invert= 28.00' / 27.80' S= 0.0095 '/' Cc= 0.900 n= 0.010, Flow Area= 3.14 sf #2 Device 1 28.00'6.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Device 1 29.25'2.5' long Sharp-Crested Rectangular Weir 0 End Contraction(s) Primary OutFlow Max=13.21 cfs @ 12.19 hrs HW=30.53' (Free Discharge) 1=Culvert (Passes 13.21 cfs of 19.54 cfs potential flow) 2=Orifice/Grate (Orifice Controls 1.43 cfs @ 7.26 fps) 3=Sharp-Crested Rectangular Weir (Weir Controls 11.79 cfs @ 3.69 fps) NOAA 24-hr A 100-yr Rainfall=12.70"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 64HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Pond 5P: BMP 1 - Chamber Wizard Field A Chamber Model = CMP Arch 71x47 (1/2" Corrugated Pipe Arch, AISI Handbook 1994, Table 2.18) Effective Size= 71.0"W x 47.0"H => 18.31 sf x 20.00'L = 366.1 cf Overall Size= 71.0"W x 47.0"H x 20.00'L Row Length Adjustment= -7.00' x 18.31 sf x 5 rows 71.0" Wide + 36.0" Spacing = 107.0" C-C Row Spacing 9 Chambers/Row x 20.00' Long -7.00' Row Adjustment +5.92' Header x 1 = 178.92' Row Length +24.0" End Stone x 2 = 182.92' Base Length 5 Rows x 71.0" Wide + 36.0" Spacing x 4 + 24.0" Side Stone x 2 = 45.58' Base Width 12.0" Stone Base + 47.0" Chamber Height + 12.0" Stone Cover = 5.92' Field Height 45 Chambers x 366.1 cf -7.00' Row Adjustment x 18.31 sf x 5 Rows + 41.58' Header x 18.31 sf = 16,597.0 cf Chamber Storage 49,332.9 cf Field - 16,597.0 cf Chambers = 32,735.8 cf Stone x 40.0% Voids = 13,094.3 cf Stone Storage Chamber Storage + Stone Storage = 29,691.4 cf = 0.682 af Overall Storage Efficiency = 60.2% Overall System Size = 182.92' x 45.58' x 5.92' 45 Chambers 1,827.1 cy Field 1,212.4 cy Stone NOAA 24-hr A 100-yr Rainfall=12.70"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 65HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Pond 5P: BMP 1 Inflow Primary Hydrograph Time (hours) 12011511010510095908580757065605550454035302520151050 Fl o w ( c f s ) 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=1.155 ac Peak Elev=30.54' Storage=0.438 af 20.58 cfs 13.38 cfs Pond 5P: BMP 1 Primary Stage-Discharge Discharge (cfs) 35302520151050 El e v a t i o n ( f e e t ) 32 31 30 29 28 27 Culvert + Orifice/Grate Sharp-Crested Rectangular Weir NOAA 24-hr A 100-yr Rainfall=12.70"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 67HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Hydrograph for Pond 5P: BMP 1 Time (hours) Inflow (cfs) Storage (acre-feet) Elevation (feet) Primary (cfs) 0.00 0.00 0.000 27.00 0.00 2.50 0.03 0.001 27.02 0.00 5.00 0.10 0.015 27.20 0.00 7.50 0.20 0.044 27.58 0.00 10.00 0.51 0.103 28.24 0.16 12.50 3.41 0.349 29.91 5.64 15.00 0.36 0.214 29.01 0.83 17.50 0.21 0.138 28.49 0.47 20.00 0.15 0.109 28.28 0.20 22.50 0.11 0.101 28.22 0.14 25.00 0.00 0.092 28.15 0.06 27.50 0.00 0.084 28.08 0.02 30.00 0.00 0.082 28.05 0.01 32.50 0.00 0.080 28.04 0.01 35.00 0.00 0.079 28.03 0.00 37.50 0.00 0.079 28.02 0.00 40.00 0.00 0.078 28.02 0.00 42.50 0.00 0.078 28.01 0.00 45.00 0.00 0.078 28.01 0.00 47.50 0.00 0.077 28.01 0.00 50.00 0.00 0.077 28.01 0.00 52.50 0.00 0.077 28.01 0.00 55.00 0.00 0.077 28.01 0.00 57.50 0.00 0.077 28.01 0.00 60.00 0.00 0.077 28.01 0.00 62.50 0.00 0.077 28.01 0.00 65.00 0.00 0.077 28.01 0.00 67.50 0.00 0.077 28.01 0.00 70.00 0.00 0.077 28.00 0.00 72.50 0.00 0.077 28.00 0.00 75.00 0.00 0.077 28.00 0.00 77.50 0.00 0.077 28.00 0.00 80.00 0.00 0.077 28.00 0.00 82.50 0.00 0.077 28.00 0.00 85.00 0.00 0.077 28.00 0.00 87.50 0.00 0.077 28.00 0.00 90.00 0.00 0.077 28.00 0.00 92.50 0.00 0.077 28.00 0.00 95.00 0.00 0.077 28.00 0.00 97.50 0.00 0.077 28.00 0.00 100.00 0.00 0.077 28.00 0.00 102.50 0.00 0.077 28.00 0.00 105.00 0.00 0.077 28.00 0.00 107.50 0.00 0.077 28.00 0.00 110.00 0.00 0.077 28.00 0.00 112.50 0.00 0.077 28.00 0.00 115.00 0.00 0.077 28.00 0.00 117.50 0.00 0.077 28.00 0.00 120.00 0.00 0.077 28.00 0.00 NOAA 24-hr A 100-yr Rainfall=12.70"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 68HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Stage-Discharge for Pond 5P: BMP 1 Elevation (feet) Primary (cfs) 27.00 0.00 27.05 0.00 27.10 0.00 27.15 0.00 27.20 0.00 27.25 0.00 27.30 0.00 27.35 0.00 27.40 0.00 27.45 0.00 27.50 0.00 27.55 0.00 27.60 0.00 27.65 0.00 27.70 0.00 27.75 0.00 27.80 0.00 27.85 0.00 27.90 0.00 27.95 0.00 28.00 0.00 28.05 0.01 28.10 0.03 28.15 0.07 28.20 0.11 28.25 0.17 28.30 0.23 28.35 0.30 28.40 0.36 28.45 0.43 28.50 0.47 28.55 0.52 28.60 0.56 28.65 0.60 28.70 0.63 28.75 0.67 28.80 0.70 28.85 0.73 28.90 0.76 28.95 0.79 29.00 0.82 29.05 0.85 29.10 0.87 29.15 0.90 29.20 0.92 29.25 0.95 29.30 1.06 29.35 1.25 29.40 1.49 29.45 1.77 29.50 2.08 29.55 2.42 29.60 2.79 Elevation (feet) Primary (cfs) 29.65 3.19 29.70 3.61 29.75 4.05 29.80 4.51 29.85 5.00 29.90 5.50 29.95 6.02 30.00 6.56 30.05 7.12 30.10 7.69 30.15 8.28 30.20 8.89 30.25 9.51 30.30 10.15 30.35 10.80 30.40 11.47 30.45 12.15 30.50 12.84 30.55 13.55 30.60 14.27 30.65 15.01 30.70 15.75 30.75 16.51 30.80 17.29 30.85 18.07 30.90 18.87 30.95 19.67 31.00 20.49 31.05 21.32 31.10 22.17 31.15 23.02 31.20 23.88 31.25 24.76 31.30 25.65 31.35 26.54 31.40 27.40 31.45 27.82 31.50 28.24 31.55 28.65 31.60 29.06 31.65 29.46 31.70 29.86 31.75 30.25 31.80 30.63 31.85 31.01 31.90 31.39 31.95 31.76 32.00 32.13 32.05 32.49 32.10 32.85 32.15 33.20 32.20 33.55 32.25 33.90 Elevation (feet) Primary (cfs) 32.30 34.25 32.35 34.59 32.40 34.87 32.45 35.12 32.50 35.37 32.55 35.63 32.60 35.88 32.65 36.12 32.70 36.37 32.75 36.62 32.80 36.86 32.85 37.10 32.90 37.34 NOAA 24-hr A 100-yr Rainfall=12.70"Market Street - hydrocad - 221214 Printed 1/11/2023Prepared by Seamon Whiteside Page 69HydroCAD® 10.20-2b s/n 12150 © 2021 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond 5P: BMP 1 Elevation (feet) Storage (acre-feet) 27.00 0.000 27.05 0.004 27.10 0.008 27.15 0.011 27.20 0.015 27.25 0.019 27.30 0.023 27.35 0.027 27.40 0.031 27.45 0.034 27.50 0.038 27.55 0.042 27.60 0.046 27.65 0.050 27.70 0.054 27.75 0.057 27.80 0.061 27.85 0.065 27.90 0.069 27.95 0.073 28.00 0.077 28.05 0.081 28.10 0.086 28.15 0.092 28.20 0.098 28.25 0.105 28.30 0.111 28.35 0.118 28.40 0.125 28.45 0.132 28.50 0.139 28.55 0.146 28.60 0.153 28.65 0.160 28.70 0.168 28.75 0.175 28.80 0.182 28.85 0.190 28.90 0.197 28.95 0.205 29.00 0.212 29.05 0.220 29.10 0.227 29.15 0.235 29.20 0.242 29.25 0.250 29.30 0.257 29.35 0.265 29.40 0.272 29.45 0.280 29.50 0.287 29.55 0.295 29.60 0.302 Elevation (feet) Storage (acre-feet) 29.65 0.310 29.70 0.317 29.75 0.324 29.80 0.332 29.85 0.339 29.90 0.347 29.95 0.354 30.00 0.361 30.05 0.369 30.10 0.376 30.15 0.383 30.20 0.390 30.25 0.398 30.30 0.405 30.35 0.412 30.40 0.419 30.45 0.426 30.50 0.433 30.55 0.440 30.60 0.447 30.65 0.454 30.70 0.461 30.75 0.468 30.80 0.474 30.85 0.481 30.90 0.488 30.95 0.494 31.00 0.501 31.05 0.507 31.10 0.514 31.15 0.520 31.20 0.526 31.25 0.533 31.30 0.539 31.35 0.545 31.40 0.551 31.45 0.557 31.50 0.562 31.55 0.568 31.60 0.574 31.65 0.579 31.70 0.584 31.75 0.590 31.80 0.595 31.85 0.599 31.90 0.604 31.95 0.608 32.00 0.611 32.05 0.615 32.10 0.619 32.15 0.623 32.20 0.627 32.25 0.631 Elevation (feet) Storage (acre-feet) 32.30 0.634 32.35 0.638 32.40 0.642 32.45 0.646 32.50 0.650 32.55 0.654 32.60 0.657 32.65 0.661 32.70 0.665 32.75 0.669 32.80 0.673 32.85 0.677 32.90 0.680 National Flood Hazard Layer FIRMette 0 500 1,000 1,500 2,000250 Feet Ü SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT SPECIAL FLOODHAZARD AREAS Without Base Flood Elevation (BFE)Zone A, V, A99With BFE or DepthZone AE, AO, AH, VE, AR Regulatory Floodway 0.2% Annual Chance Flood Hazard, Areasof 1% annual chance flood with averagedepth less than one foot or with drainageareas of less than one square mileZone X Future Conditions 1% Annual Chance Flood HazardZone X Area with Reduced Flood Risk due to Levee. See Notes.Zone X Area with Flood Risk due to LeveeZone D NO SCREENArea of Minimal Flood Hazard Zone X Area of Undetermined Flood HazardZone D Channel, Culvert, or Storm Sewer Levee, Dike, or Floodwall Cross Sections with 1% Annual Chance 17.5 Water Surface Elevation Coastal Transect Coastal Transect Baseline Profile Baseline Hydrographic Feature Base Flood Elevation Line (BFE) Effective LOMRs Limit of Study Jurisdiction Boundary Digital Data Available No Digital Data Available Unmapped This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below.The basemap shown complies with FEMA's basemapaccuracy standards The flood hazard information is derived directly from theauthoritative NFHL web services provided by FEMA. This mapwas exported on 8/23/2022 at 5:06 PM and does notreflect changes or amendments subsequent to this date andtime. The NFHL and effective information may change orbecome superseded by new data over time. This map image is void if the one or more of the following map elements 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 unmapped and unmodernized areas cannot be used for regulatory purposes. Legend OTHER AREAS OF FLOOD HAZARD OTHER AREAS GENERAL STRUCTURES OTHER FEATURES MAP PANELS 8 B 20.2 The pin displayed on the map is an approximatepoint selected by the user and does not representan authoritative property location. 1:6,000 77°48'12"W 34°17'48"N 77°47'35"W 34°17'19"N Basemap: USGS National Map: Orthoimagery: Data refreshed October, 2020 10/26/22, 11:57 AM Precipitation Frequency Data Server https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=34.2926&lon=-77.7983&data=depth&units=english&series=pds 1/4 NOAA Atlas 14, Volume 2, Version 3 Location name: Wilmington, North Carolina, USA* Latitude: 34.2926°, Longitude: -77.7983° Elevation: 31.73 ft** * source: ESRI Maps ** 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 | PF_graphical | Maps_&_aerials PF tabular PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1 Duration Average recurrence interval (years) 1 2 5 10 25 50 100 200 500 1000 5-min 0.521 (0.486‑0.563) 0.619 (0.576‑0.669) 0.724 (0.672‑0.781) 0.806 (0.746‑0.869) 0.910 (0.838‑0.979) 0.988 (0.906‑1.06) 1.07 (0.974‑1.15) 1.15 (1.04‑1.24) 1.25 (1.12‑1.35) 1.34 (1.19‑1.45) 10-min 0.832 (0.775‑0.899) 0.991 (0.921‑1.07) 1.16 (1.08‑1.25) 1.29 (1.19‑1.39) 1.45 (1.34‑1.56) 1.57 (1.44‑1.69) 1.70 (1.55‑1.83) 1.82 (1.65‑1.96) 1.98 (1.78‑2.14) 2.11 (1.87‑2.28) 15-min 1.04 (0.969‑1.12) 1.25 (1.16‑1.35) 1.47 (1.36‑1.58) 1.63 (1.51‑1.76) 1.84 (1.69‑1.98) 1.99 (1.83‑2.15) 2.15 (1.96‑2.31) 2.30 (2.08‑2.48) 2.49 (2.24‑2.70) 2.65 (2.35‑2.87) 30-min 1.43 (1.33‑1.54) 1.72 (1.60‑1.86) 2.09 (1.94‑2.25) 2.36 (2.19‑2.55) 2.72 (2.51‑2.93) 3.00 (2.75‑3.23) 3.29 (3.00‑3.54) 3.57 (3.24‑3.85) 3.97 (3.56‑4.29) 4.28 (3.81‑4.64) 60-min 1.78 (1.66‑1.92) 2.16 (2.01‑2.33) 2.67 (2.48‑2.88) 3.08 (2.85‑3.32) 3.62 (3.34‑3.90) 4.07 (3.73‑4.38) 4.53 (4.13‑4.88) 5.01 (4.54‑5.41) 5.69 (5.11‑6.16) 6.25 (5.56‑6.77) 2-hr 2.11 (1.94‑2.30) 2.57 (2.37‑2.81) 3.27 (3.01‑3.57) 3.85 (3.54‑4.21) 4.70 (4.29‑5.12) 5.42 (4.92‑5.90) 6.20 (5.60‑6.75) 7.06 (6.33‑7.68) 8.33 (7.39‑9.08) 9.43 (8.29‑10.3) 3-hr 2.25 (2.07‑2.47) 2.74 (2.52‑3.01) 3.51 (3.22‑3.85) 4.17 (3.81‑4.56) 5.15 (4.67‑5.62) 6.00 (5.42‑6.55) 6.95 (6.23‑7.58) 8.01 (7.12‑8.72) 9.62 (8.44‑10.5) 11.0 (9.56‑12.0) 6-hr 2.79 (2.57‑3.08) 3.41 (3.14‑3.75) 4.36 (4.00‑4.80) 5.19 (4.74‑5.70) 6.43 (5.84‑7.04) 7.52 (6.78‑8.23) 8.74 (7.82‑9.56) 10.1 (8.95‑11.1) 12.2 (10.7‑13.3) 14.1 (12.1‑15.4) 12-hr 3.27 (2.99‑3.63) 3.99 (3.64‑4.42) 5.14 (4.68‑5.70) 6.15 (5.57‑6.80) 7.68 (6.89‑8.46) 9.04 (8.06‑9.94) 10.6 (9.36‑11.6) 12.3 (10.8‑13.5) 15.0 (12.9‑16.5) 17.4 (14.8‑19.1) 24-hr 3.86 (3.51‑4.30) 4.69 (4.26‑5.23) 6.07 (5.51‑6.76) 7.28 (6.59‑8.09) 9.13 (8.18‑10.1) 10.8 (9.57‑12.0) 12.7 (11.1‑14.1) 14.8 (12.8‑16.5) 18.1 (15.4‑20.3) 21.1 (17.5‑23.7) 2-day 4.57 (4.18‑5.07) 5.53 (5.06‑6.14) 7.10 (6.47‑7.88) 8.46 (7.68‑9.39) 10.5 (9.48‑11.7) 12.4 (11.0‑13.8) 14.4 (12.7‑16.1) 16.8 (14.6‑18.8) 20.4 (17.3‑22.9) 23.5 (19.6‑26.7) 3-day 4.88 (4.46‑5.41) 5.90 (5.40‑6.53) 7.52 (6.86‑8.33) 8.92 (8.10‑9.88) 11.0 (9.92‑12.2) 12.9 (11.5‑14.3) 14.9 (13.2‑16.6) 17.2 (15.0‑19.2) 20.8 (17.7‑23.3) 23.9 (20.0‑27.0) 4-day 5.19 (4.75‑5.75) 6.26 (5.74‑6.93) 7.94 (7.24‑8.79) 9.37 (8.52‑10.4) 11.5 (10.4‑12.7) 13.3 (11.9‑14.8) 15.4 (13.6‑17.1) 17.7 (15.4‑19.7) 21.2 (18.1‑23.7) 24.2 (20.4‑27.4) 7-day 5.97 (5.51‑6.53) 7.20 (6.65‑7.88) 9.06 (8.34‑9.91) 10.6 (9.73‑11.6) 12.9 (11.7‑14.1) 14.8 (13.4‑16.2) 16.9 (15.1‑18.5) 19.2 (17.0‑21.1) 22.5 (19.6‑25.0) 25.4 (21.8‑28.3) 10-day 6.75 (6.24‑7.35) 8.09 (7.48‑8.81) 10.0 (9.25‑10.9) 11.7 (10.7‑12.7) 14.0 (12.8‑15.3) 16.0 (14.5‑17.4) 18.1 (16.3‑19.8) 20.4 (18.2‑22.4) 23.8 (20.9‑26.3) 26.6 (23.1‑29.7) 20-day 9.05 (8.42‑9.75) 10.8 (10.0‑11.6) 13.1 (12.2‑14.2) 15.1 (14.0‑16.3) 17.9 (16.5‑19.3) 20.1 (18.5‑21.8) 22.6 (20.5‑24.5) 25.2 (22.7‑27.4) 28.8 (25.6‑31.6) 31.9 (28.0‑35.2) 30-day 11.1 (10.4‑11.9) 13.2 (12.4‑14.1) 15.8 (14.8‑16.9) 18.0 (16.8‑19.2) 20.9 (19.5‑22.4) 23.3 (21.6‑25.0) 25.8 (23.8‑27.7) 28.3 (25.9‑30.5) 31.9 (28.8‑34.6) 34.7 (31.0‑37.8) 45-day 13.8 (13.0‑14.7) 16.3 (15.4‑17.4) 19.4 (18.3‑20.7) 21.9 (20.6‑23.3) 25.3 (23.7‑27.0) 28.0 (26.1‑29.9) 30.8 (28.5‑32.9) 33.7 (31.0‑36.2) 37.6 (34.2‑40.6) 40.7 (36.7‑44.3) 60-day 16.6 (15.7‑17.6) 19.5 (18.5‑20.8) 22.9 (21.6‑24.3) 25.6 (24.1‑27.1) 29.1 (27.3‑30.9) 31.9 (29.8‑33.9) 34.7 (32.3‑37.0) 37.5 (34.7‑40.1) 41.2 (37.8‑44.3) 44.1 (40.2‑47.7) 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 frequencyestimates (for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values. Please refer to NOAA Atlas 14 document for more information. Back to Top 10/26/22, 11:58 AM Precipitation Frequency Data Server https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=34.2926&lon=-77.7983&data=intensity&units=english&series=pds 1/4 NOAA Atlas 14, Volume 2, Version 3 Location name: Wilmington, North Carolina, USA* Latitude: 34.2926°, Longitude: -77.7983° Elevation: 31.73 ft** * source: ESRI Maps ** 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 | PF_graphical | Maps_&_aerials PF tabular PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches/hour)1 Duration Average recurrence interval (years) 1 2 5 10 25 50 100 200 500 1000 5-min 6.25 (5.83‑6.76) 7.43 (6.91‑8.03) 8.69 (8.06‑9.37) 9.67 (8.95‑10.4) 10.9 (10.1‑11.7) 11.9 (10.9‑12.8) 12.8 (11.7‑13.8) 13.8 (12.5‑14.9) 15.0 (13.5‑16.2) 16.1 (14.3‑17.4) 10-min 4.99 (4.65‑5.39) 5.95 (5.53‑6.42) 6.96 (6.46‑7.51) 7.73 (7.16‑8.33) 8.70 (8.02‑9.36) 9.44 (8.65‑10.2) 10.2 (9.29‑11.0) 10.9 (9.89‑11.8) 11.9 (10.7‑12.9) 12.6 (11.2‑13.7) 15-min 4.16 (3.88‑4.49) 4.98 (4.63‑5.38) 5.87 (5.45‑6.33) 6.52 (6.04‑7.03) 7.35 (6.77‑7.91) 7.97 (7.30‑8.58) 8.58 (7.83‑9.24) 9.18 (8.32‑9.90) 9.98 (8.94‑10.8) 10.6 (9.40‑11.5) 30-min 2.85 (2.66‑3.08) 3.44 (3.20‑3.72) 4.17 (3.87‑4.50) 4.72 (4.37‑5.09) 5.44 (5.02‑5.86) 6.00 (5.50‑6.46) 6.57 (5.99‑7.08) 7.15 (6.48‑7.71) 7.94 (7.12‑8.58) 8.57 (7.62‑9.28) 60-min 1.78 (1.66‑1.92) 2.16 (2.01‑2.33) 2.67 (2.48‑2.88) 3.08 (2.85‑3.32) 3.62 (3.34‑3.90) 4.07 (3.73‑4.38) 4.53 (4.13‑4.88) 5.01 (4.54‑5.41) 5.69 (5.11‑6.16) 6.25 (5.56‑6.77) 2-hr 1.05 (0.970‑1.15) 1.29 (1.18‑1.40) 1.64 (1.51‑1.79) 1.93 (1.77‑2.10) 2.35 (2.14‑2.56) 2.71 (2.46‑2.95) 3.10 (2.80‑3.38) 3.53 (3.16‑3.84) 4.17 (3.69‑4.54) 4.71 (4.15‑5.16) 3-hr 0.749 (0.690‑0.824) 0.913 (0.840‑1.00) 1.17 (1.07‑1.28) 1.39 (1.27‑1.52) 1.71 (1.56‑1.87) 2.00 (1.81‑2.18) 2.31 (2.07‑2.53) 2.67 (2.37‑2.90) 3.20 (2.81‑3.49) 3.67 (3.18‑4.01) 6-hr 0.467 (0.429‑0.514) 0.569 (0.524‑0.627) 0.728 (0.668‑0.802) 0.867 (0.792‑0.953) 1.07 (0.975‑1.18) 1.25 (1.13‑1.38) 1.46 (1.31‑1.60) 1.69 (1.49‑1.85) 2.04 (1.78‑2.23) 2.35 (2.03‑2.57) 12-hr 0.272 (0.248‑0.302) 0.331 (0.302‑0.367) 0.427 (0.389‑0.473) 0.511 (0.463‑0.564) 0.637 (0.572‑0.703) 0.750 (0.669‑0.825) 0.877 (0.776‑0.964) 1.02 (0.894‑1.12) 1.24 (1.07‑1.37) 1.44 (1.23‑1.59) 24-hr 0.161 (0.146‑0.179) 0.195 (0.178‑0.218) 0.253 (0.229‑0.282) 0.303 (0.274‑0.337) 0.381 (0.341‑0.423) 0.450 (0.399‑0.499) 0.528 (0.463‑0.587) 0.617 (0.534‑0.687) 0.756 (0.640‑0.846) 0.879 (0.730‑0.988) 2-day 0.095 (0.087‑0.106) 0.115 (0.105‑0.128) 0.148 (0.135‑0.164) 0.176 (0.160‑0.196) 0.220 (0.197‑0.244) 0.258 (0.230‑0.287) 0.301 (0.265‑0.335) 0.350 (0.304‑0.392) 0.425 (0.361‑0.478) 0.490 (0.409‑0.556) 3-day 0.068 (0.062‑0.075) 0.082 (0.075‑0.091) 0.104 (0.095‑0.116) 0.124 (0.112‑0.137) 0.153 (0.138‑0.170) 0.179 (0.159‑0.198) 0.207 (0.183‑0.231) 0.239 (0.208‑0.267) 0.288 (0.246‑0.324) 0.331 (0.278‑0.375) 4-day 0.054 (0.049‑0.060) 0.065 (0.060‑0.072) 0.083 (0.075‑0.092) 0.098 (0.089‑0.108) 0.120 (0.108‑0.133) 0.139 (0.124‑0.154) 0.160 (0.142‑0.178) 0.184 (0.161‑0.205) 0.220 (0.189‑0.247) 0.252 (0.213‑0.285) 7-day 0.036 (0.033‑0.039) 0.043 (0.040‑0.047) 0.054 (0.050‑0.059) 0.063 (0.058‑0.069) 0.077 (0.070‑0.084) 0.088 (0.080‑0.096) 0.101 (0.090‑0.110) 0.114 (0.101‑0.126) 0.134 (0.117‑0.149) 0.151 (0.130‑0.169) 10-day 0.028 (0.026‑0.031) 0.034 (0.031‑0.037) 0.042 (0.039‑0.046) 0.049 (0.045‑0.053) 0.058 (0.053‑0.064) 0.067 (0.061‑0.073) 0.075 (0.068‑0.083) 0.085 (0.076‑0.093) 0.099 (0.087‑0.110) 0.111 (0.096‑0.124) 20-day 0.019 (0.018‑0.020) 0.022 (0.021‑0.024) 0.027 (0.025‑0.030) 0.031 (0.029‑0.034) 0.037 (0.034‑0.040) 0.042 (0.038‑0.045) 0.047 (0.043‑0.051) 0.052 (0.047‑0.057) 0.060 (0.053‑0.066) 0.066 (0.058‑0.073) 30-day 0.015 (0.014‑0.016) 0.018 (0.017‑0.020) 0.022 (0.021‑0.023) 0.025 (0.023‑0.027) 0.029 (0.027‑0.031) 0.032 (0.030‑0.035) 0.036 (0.033‑0.038) 0.039 (0.036‑0.042) 0.044 (0.040‑0.048) 0.048 (0.043‑0.052) 45-day 0.013 (0.012‑0.014) 0.015 (0.014‑0.016) 0.018 (0.017‑0.019) 0.020 (0.019‑0.022) 0.023 (0.022‑0.025) 0.026 (0.024‑0.028) 0.029 (0.026‑0.031) 0.031 (0.029‑0.033) 0.035 (0.032‑0.038) 0.038 (0.034‑0.041) 60-day 0.012 (0.011‑0.012) 0.014 (0.013‑0.014) 0.016 (0.015‑0.017) 0.018 (0.017‑0.019) 0.020 (0.019‑0.021) 0.022 (0.021‑0.024) 0.024 (0.022‑0.026) 0.026 (0.024‑0.028) 0.029 (0.026‑0.031) 0.031 (0.028‑0.033) 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 (fora given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values. Please refer to NOAA Atlas 14 document for more information. Back to Top Soil Map—New Hanover County, North Carolina Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/25/2022 Page 1 of 3 37 9 8 1 1 0 37 9 8 1 3 0 37 9 8 1 5 0 37 9 8 1 7 0 37 9 8 1 9 0 37 9 8 2 1 0 37 9 8 2 3 0 37 9 8 2 5 0 37 9 8 2 7 0 37 9 8 2 9 0 37 9 8 1 1 0 37 9 8 1 3 0 37 9 8 1 5 0 37 9 8 1 7 0 37 9 8 1 9 0 37 9 8 2 1 0 37 9 8 2 3 0 37 9 8 2 5 0 37 9 8 2 7 0 37 9 8 2 9 0 242370 242390 242410 242430 242450 242470 242490 242510 242370 242390 242410 242430 242450 242470 242490 242510 34° 17' 38'' N 77 ° 4 7 ' 5 6 ' ' W 34° 17' 38'' N 77 ° 4 7 ' 5 0 ' ' W 34° 17' 32'' N 77 ° 4 7 ' 5 6 ' ' W 34° 17' 32'' N 77 ° 4 7 ' 5 0 ' ' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 18N WGS84 0 45 90 180 270 Feet 0 10 20 40 60 Meters Map Scale: 1:986 if printed on A portrait (8.5" x 11") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:15,800. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the 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: New Hanover County, North Carolina Survey Area Data: Version 23, Jan 21, 2022 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Oct 5, 2020—Nov 24, 2020 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. Soil Map—New Hanover County, North Carolina Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/25/2022 Page 2 of 3 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI Le Leon sand 1.9 89.3% Mu Murville fine sand 0.2 10.7% Totals for Area of Interest 2.1 100.0% Soil Map—New Hanover County, North Carolina Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/25/2022 Page 3 of 3 ECS Southeast, LLP Geotechnical Engineering Report Tidal Wave Auto Spa - Wilmington Wilmington, New Hanover County, North Carolina ECS Project No. 22:31390 February 25, 2022 February 25, 2022 Mr. Brian Braun, PE Advanced Engineering Services, LLC 110-A Tommy Stalnaker Drive Warner Robins, Georgia 31088 ECS Project No. 22:31390 Reference: Geotechnical Engineering Report Tidal Wave Auto Spa - Wilmington Wilmington, New Hanover County, North Carolina Dear Mr. Braun: ECS Southeast, LLP (ECS) has finished the subsurface exploration and geotechnical engineering analyses for the above-referenced project. Our services were performed in general accordance with our agreed to scope of work. This report presents our understanding of the geotechnical aspects of the project along with the results of the field exploration and our design and construction recommendations. It has been our pleasure to be of service to Advanced Engineering Services, LLC during the design phase of this project. We would appreciate the opportunity to remain involved during the continuation of the design phase, and we would like to provide our services during construction phase operations as well to verify subsurface conditions assumed for this report. Should you have questions concerning the information contained in this report, or if we can be of further assistance to you, please contact us. Respectfully submitted, ECS Southeast, LLP Annemarie Crumrine, PE Winslow Goins, PE Project Manager Principal Engineer ACrumrine@ecslimited.com WGoins@ecslimited.com 2/25/22 Tidal Wave Auto Spa - Wilmington February 25, 2022 ECS Project No. 22:31390 Page i TABLE OF CONTENTS EXECUTIVE SUMMARY ............................................................................................................. 1 1.0 INTRODUCTION .................................................................................................................. 2 2.0 PROJECT INFORMATION ..................................................................................................... 3 2.1 Project Location/Current Site Use/Past Site Use ................................................................... 3 2.2 Proposed Construction ........................................................................................................... 3 3.0 FIELD EXPLORATION testing ................................................................................................ 4 3.1 Subsurface Characterization .................................................................................................. 4 3.2 Groundwater Observations .................................................................................................... 4 4.0 DESIGN RECOMMENDATIONS ............................................................................................. 5 4.1 Shallow Foundations .............................................................................................................. 5 4.2 Slabs On Grade ....................................................................................................................... 5 4.3 Seismic Design Considerations ............................................................................................... 6 4.4 Pavements .............................................................................................................................. 7 5.0 SITE CONSTRUCTION RECOMMENDATIONS ....................................................................... 10 5.1 Subgrade Preparation .......................................................................................................... 10 5.1.1 Stripping and Grubbing ............................................................................................... 10 5.1.2 Proofrolling ................................................................................................................. 10 5.2 Earthwork Operations .......................................................................................................... 10 5.2.1 Structural Fill ............................................................................................................... 10 5.3 Foundation and Slab Observations ...................................................................................... 11 5.4 Utility Installations ............................................................................................................... 12 6.0 CLOSING ........................................................................................................................... 13 APPENDICES Appendix A – Drawings & Reports • Site Location Diagram • Exploration Location Diagram Appendix B – Field Operations • Reference Notes for CPT Soundings • Cone Penetration Test Sounding Logs (S-1 through S-3) • Reference Notes for Boring Logs • Hand Auger Boring Logs (K-1 through K-4) • Kessler DCP Test Data Appendix C – Supplemental Report Documents • GBA Document Tidal Wave Auto Spa - Wilmington February 25, 2022 ECS Project No. 22:31390 Page 1 EXECUTIVE SUMMARY The following summarizes the main findings of the exploration, particularly those that may have a cost impact on the planned development. Further, our principal foundation recommendations are summarized. Information gleaned from the executive summary should not be utilized in lieu of reading the geotechnical report. • The geotechnical exploration performed for the site included three (3) electronic cone penetration test (CPT) soundings drilled to termination and refusal depths of approximately 10 to 33.5 feet. Four (4) Kessler dynamic cone penetrometer (DCP) tests with hand auger borings were performed in the proposed pavements. • Provided the subgrades are prepared as recommended in this report and the column and wall loads do not exceed the anticipated column and wall loads provided in the table in Section 2.2, the planned structures may be supported by conventional shallow foundations consisting of column or strip footings bearing on compacted structural fill and natural soils using a net allowable soil bearing pressure of 3,000 psf. • Groundwater was encountered in the soundings at depths ranging from approximately 4.4 feet to 7.33 feet below existing grade. Groundwater was not encountered in the hand auger borings K-1 through and K-4 at the depths explored. • Due to the near surface loose sands encountered in the hand auger borings K-1 and K-4, in-place densification should be anticipated to be performed in the vicinity of the borings prior to construction of pavements or placement of Structural Fill. Please note this Executive Summary is an important part of this report and should be considered a “summary” only. The subsequent sections of this report constitute our findings, conclusions, and recommendations in their entirety. Tidal Wave Auto Spa - Wilmington February 25, 2022 ECS Project No. 22:31390 Page 2 1.0 INTRODUCTION The purpose of this study was to provide geotechnical information for the design of foundations and pavements for the proposed Tidal Wave carwash located at 8005 and 8015 Market Street in Wilmington, North Carolina. The recommendations developed for this report are based on project information supplied by Mr. Brian Braun, PE of Advanced Engineering Services, LLC. Our services were provided in accordance with our Proposal No. 22:25948, dated February 2, 2022, as authorized by Mr. Brian Braun, PE of Advanced Engineering Services, LLC. This report contains the procedures and results of our subsurface exploration programs, review of existing site conditions, engineering analyses, and recommendations for the design and construction of the project. The report includes the following items. • A brief review and description of our field test procedures and the results of testing conducted; • A review of surface topographical features and site conditions; • A review of subsurface soil stratigraphy with pertinent available physical properties; • Foundation recommendations; o Allowable bearing pressure; o Settlement estimates (total and differential); • Site development recommendations; • Reusability of soils for use as fill material; • Pavement design recommendations; • Seismic site class and liquefaction recommendations; • Discussion of groundwater impact; • Compaction recommendations; • Site vicinity map; • Exploration location plan; • Hand Auger boring logs with Kessler DCP test results; and • CPT sounding logs. Tidal Wave Auto Spa - Wilmington February 25, 2022 ECS Project No. 22:31390 Page 3 2.0 PROJECT INFORMATION 2.1 PROJECT LOCATION/CURRENT SITE USE/PAST SITE USE The proposed site is located at 8005 and 8015 Market Street in Wilmington, North Carolina. The site is bounded on the southeast by Market Street, on the southwest by Sweetwater Drive, on the northwest by existing residential properties, and on the northeast by the existing paved driveway for the Walmart shopping center. Figure 2.1.1 below shows an image of where the site is located. Figure 2.1.1 Site Location At the time of our exploration, the site currently consisted of an open site with some vegetation. ECS understands the site consists of two parcels that total approximately 1.7 acres. Based on our site visit and approximate elevations from Google Earth, the site is relatively level with typical elevations on site ranging from approximately 30 to 33 feet. 2.2 PROPOSED CONSTRUCTION The following information explains our understanding and assumptions of the planned development including proposed building and related infrastructure. SUBJECT DESIGN INFORMATION / ASSUMPTIONS Usage Car Wash Column Loads Up to 125 kips Wall Loads Up to 6 kips per linear foot (klf) Finish Floor Elevation within +/- 4 feet of existing grades ECS understands the project consists of construction of a new approximately 2,310 square foot Carwash building and an adjacent 896 square foot equipment room with associated paved drives, dumpster pad, and parking throughout the site. Tidal Wave Auto Spa - Wilmington February 25, 2022 ECS Project No. 22:31390 Page 4 3.0 FIELD EXPLORATION TESTING Our exploration procedures are explained in greater detail in Appendix B including the Reference Notes for Cone Penetration Soundings. Our scope of work included performing three (3) CPT soundings and four (4) hand auger borings with Kessler DCP tests. Our approximate CPT soundings and hand auger boring locations are shown on the Exploration Location Diagram in Appendix A. 3.1 SUBSURFACE CHARACTERIZATION The subsurface conditions encountered were generally consistent with published geological mapping. The following sections provide generalized characterizations of the soil. Please refer to the CPT sounding logs in Appendix B. The site is located in the Coastal Plain Physiographic Province of North Carolina. The Coastal Plain is composed of seven terraces, each representing a former level of the Atlantic Ocean. Soils in this area generally consist of sedimentary materials transported from other areas by the ocean or rivers. These deposits vary in thickness from a thin veneer along the western edge of the region to more than 10,000 feet near the coast. The sedimentary deposits of the Coastal Plain rest upon consolidated rocks similar to those underlying the Piedmont and Mountain Physiographic Provinces. In general, shallow unconfined groundwater movement within the overlying soils is largely controlled by topographic gradients. Recharge occurs primarily by infiltration along higher elevations and typically discharges into streams or other surface water bodies. The elevation of the shallow water table is transient and can vary greatly with seasonal fluctuations in precipitation. Table 3.1.1 Subsurface Stratigraphy Approximate Depth Range Stratum Description Ranges of N*-Values(1) blows per foot (bpf) 0 to (0.2-0.5) (Surface cover) N/A Topsoil was encountered on-site with an observed thickness of approximately 2 to 6 inches. Deeper topsoil or organic laden soils are likely present in wet, poorly drained areas and potentially unexplored areas of the site. N/A (0.2-0.5) to 10 I Very Loose to Medium Dense, SILTY TO CLEAN SAND (SM, SP) 3 to 25 10 to 25 II Very Soft to Stiff, CLAYEY SILT (ML) and SILTY, SANDY LEAN, and LEAN CLAY (CL-ML, CL) with interbedded layers of Very Loose to Medium Dense, SILTY TO CLEAN SAND (SM, SP) 2 to 28 25 to 30 III Loose to Medium Dense, SILTY TO CLEAN SAND (SM, SP) 5 to 15 30 to 33.5 IV Very Loose to Very Dense, SILTY TO CLEAN, and CEMENTED SAND (SM, SP) with interbedded layers of Soft to Stiff, SILTY and LEAN CLAY (CL-ML, CL) 4 to 66 Notes: (1) Equivalent Corrected Standard Penetration Test Resistances 3.2 GROUNDWATER OBSERVATIONS Water levels were encountered in our CPT soundings and are shown in Appendix B. Groundwater depths measured at the time of exploration ranged from approximately 4.4 to 7.33 feet below the ground surface. Groundwater was not encountered in the hand auger borings K-1 through K-4 at the time of exploration at the depths explored. Variations in the long-term water table may occur as a result of changes in precipitation, evaporation, surface water runoff, construction activities, and other factors. Tidal Wave Auto Spa - Wilmington February 25, 2022 ECS Project No. 22:31390 Page 5 4.0 DESIGN RECOMMENDATIONS 4.1 SHALLOW FOUNDATIONS Provided subgrades and structural fills are prepared as recommended in this report and the anticipated column and wall loads in Section 2.2 are not exceeded, the proposed structures can be supported by shallow foundations including column footings and continuous wall footings. We recommend the foundation design use the following parameters: Design Parameter Column Footing Wall Footing Net Allowable Bearing Pressure(1) 3,000 psf 3,000 psf Recommended Bearing Soil Material Stratum I Soils or Structural Fill Stratum I Soils or Structural Fill Minimum Width 30 inches 18 inches Minimum Footing Embedment Depth (below slab or finished grade) (2) 12 inches 12 inches Minimum Exterior Frost Depth (below final exterior grade) 6 inches 6 inches Estimated Total Settlement (3) Less than 1- inch Less than 1- inch Estimated Differential Settlement (4) Less than ½ inches between columns Less than ½ inches Notes: (1) Net allowable bearing pressure is the applied pressure in excess of the surrounding overburden soils above the base of the foundation. (2) For bearing considerations and frost penetration requirements. (3) Based on assumed structural loads. If final loads are different, ECS must be contacted to update foundation recommendations and settlement calculations. (4) Based on maximum column/wall loads and variability in borings. Differential settlement can be re- evaluated once the foundation plans are finished. Potential Undercuts: A majority of the soils at the estimated foundation bearing elevation are anticipated to be adequate for support of the proposed structure. If soft or loose soils are observed at the footing bearing elevations, the soils should be undercut and removed. Undercut should be backfilled with Structural Fill up to the original design bottom of footing elevation; the original footing may be constructed on top of the Structural Fill. 4.2 SLABS ON GRADE The on-site natural soils are generally considered adequate for support of the slab-on-grade floor slabs. Based on the assumption that the finished floor elevation is around current grades, it appears that the slabs for the structure will likely bear on the Stratum I SAND (SM, SP) or Structural Fill. The following graphic depicts our soil-supported slab recommendations: Tidal Wave Auto Spa - Wilmington February 25, 2022 ECS Project No. 22:31390 Page 6 Figure 4.2.1 1. Drainage Layer Thickness: 4 inches 2. Drainage Layer Material: GRAVEL (GP) or SAND containing <5% fines passing #200 sieve (SP, SW) Soft or yielding soils may be encountered in some areas. Those soils should be removed and replaced with compacted Structural Fill in accordance with the recommendations included in this report. Subgrade Modulus: Provided the Structural Fill and Granular Drainage Layer are constructed in accordance with our recommendations, the slab may be designed assuming a modulus of subgrade reaction, k1 of 175 pci (lbs./cu. inch). The modulus of subgrade reaction value is based on a 1 ft by 1 ft plate load test basis. Vapor Barrier: Before the placement of concrete, a vapor barrier may be placed on top of the granular drainage layer to provide additional protection against moisture penetration through the floor slab. Curing of the slab should be performed in accordance with ACI specifications to reduce the potential for uneven drying, curling and/or cracking of the slab. Depending on proposed flooring material types, the structural engineer and/or the architect may choose to do away with the vapor barrier. Slab Isolation: Soil-supported slabs should be isolated from the foundations and foundation-supported elements of the structure so that differential movement between the foundations and slab will not induce excessive shear and bending stresses in the floor slab. Where the structural configuration inhibits the use of a free-floating slab such as in a drop down footing/monolithic slab configuration, the slab should be designed to avoid overstressing of the slab. 4.3 SEISMIC DESIGN CONSIDERATIONS Seismic Site Classification: The International Building Code (IBC) 2015 requires site classification for seismic design based on the upper 100 feet of a soil profile. At least two methods are utilized in classifying sites, namely the shear wave velocity (vs) method and the Standard Penetration Resistance (N-value) method. The first method (shear wave velocity) was used in classifying this site. Based upon our interpretation of the subsurface conditions, the appropriate Seismic Site Classification is “D”. Concrete Slab Vapor Barrier Granular Drainage Layer Compacted Subgrade Tidal Wave Auto Spa - Wilmington February 25, 2022 ECS Project No. 22:31390 Page 7 Liquefaction: When a saturated soil with little to approximately no cohesion liquefies during a major earthquake, it experiences a temporary loss of shear strength as a result of a transient rise in excess pore water pressure generated by strong ground motion. Flow failure, lateral spreading, differential settlement, loss of bearing, ground fissures, and sand boils are evidence of excess pore pressure generation and liquefaction. The potential for liquefaction at the site is considered low based upon the CPT results and the liquefaction index procedure developed by Iwasaki (1982). Based on our CPT results and our evaluation using a site peak ground acceleration of 0.16 (PGAm) per IBC 2015, an earthquake event with a magnitude of 7.3 and procedures developed by Robertson (2009) and Boulanger and Idriss (2014), the liquefaction induced settlement at the subject site is estimated to be approximately 1.5 inches or less. The max differential settlement is estimated to be approximately 1.3 inches over a distance of 100 feet. Ground Motion Parameters: In addition to the seismic site classification, ECS has determined the design spectral response acceleration parameters following the IBC 2015 methodology. The Mapped Reponses were estimated from the ATC Hazards by Location Tool available from the USGS website (https://hazards.atcouncil.org). The design responses for the short (0.2 sec, SDS) and 1-second period (SD1) are noted in bold at the far right end of the following table. GROUND MOTION PARAMETERS – SITE CLASS D [IBC 2015 Method] Period (sec) Mapped Spectral Response Accelerations (g) Values of Site Coefficient for Site Class Maximum Spectral Response Acceleration Adjusted for Site Class (g) Design Spectral Response Acceleration (g) Reference Figures 1613.3.1 (1) & (2) Tables 1613.3.3 (1) & (2) Eqs. 16-37 & 16-38 Eqs. 16-39 & 16-40 0.2 SS 0.202 Fa 1.6 SMS=FaSs 0.324 SDS=2/3 SMS 0.216 1.0 S1 0.087 Fv 2.4 SM1=FvS1 0.208 SD1=2/3 SM1 0.139 The Site Class definition should not be confused with the Seismic Design Category designation which the Structural Engineer typically assesses. 4.4 PAVEMENTS Subgrade Characteristics: Based on the results of our hand auger borings, it appears that the pavement subgrades will consist mainly of SILTY and CLEAN SAND (SM, SP) or Structural Fill. Due to the near surface loose sands encountered in the hand auger borings, in-place densification should be anticipated to be performed in the vicinity of the borings, K-1 and K-4, prior to construction of pavements or placement of Structural Fill. Tidal Wave Auto Spa - Wilmington February 25, 2022 ECS Project No. 22:31390 Page 8 California Bearing Ratio (CBR) values were estimated from the Kessler DCP tests performed on site adjacent to the hand auger borings. For preliminary design purposes, provided subgrade preparation and in-place densification recommendations are followed, we recommend assuming a preliminary CBR value of 10. We were not provided traffic loading information, so we have assumed loadings typical of this type of project. Our recommended pavement sections are based on up to 25,000 ESALs over a 20 year design life for light duty and up to 75,000 ESALs over a 20 year design life for heavy duty. The preliminary pavement sections below are guidelines that may or may not comply with local jurisdictional minimums. PROPOSED PAVEMENT SECTIONS FLEXIBLE PAVEMENT RIGID PAVEMENT MATERIAL Heavy Duty Light Duty Heavy Duty Light Duty Portland Cement Concrete (f’c = 4000 psi) - - 6.5 in. 5 in. Asphalt Surface Course 3 in 2 in - - Graded Aggregate Base Course (ABC) 6 in 6 in - - In general, heavy duty sections are areas that will be subjected to trucks, buses, or other similar vehicles including main drive lanes of the development. Light duty sections are appropriate for vehicular traffic and parking areas. Large, front loading trash dumpsters frequently impose concentrated front wheel loads on pavements during loading. This type of loading typically results in rutting of asphalt pavement and ultimately pavement failures. For preliminary design purposes, we recommend that the pavement in trash pickup areas consist of a 6-inch thick, 4,000 psi, reinforced concrete slab underlain by 4-inches of aggregate base course. When traffic loading becomes available, ECS or the Civil Engineer can design the pavements. Prior to subbase placement and paving, CBR testing of the subgrade soils (both natural and fill soils) should be performed to determine the soil engineering properties for final pavement design. A minimum distance of 18 inches should be maintained between the bottom of the pavement section and the groundwater table. The soil subgrade should be smooth-rolled and proofrolled prior to ABC placement. Areas that pump, rut, or are otherwise unstable should be re-compacted or undercut and replaced. The ABC should conform to the gradation, liquid limit, plasticity index, resistance to abrasion, and soundness per Section 1005 of the 2012 NCDOT Standard Specifications for Roads and Structures. Tidal Wave Auto Spa - Wilmington February 25, 2022 ECS Project No. 22:31390 Page 9 The ABC should be placed and be compacted in accordance with Section 520 of the 2012 NCDOT Standard Specifications for Roads and Structures. The ABC should be placed in a single lift. It should be spread after end-dumping on previously-placed ABC to prevent rutting and degradation of the relatively clean sand subgrade soils by rubber-tired dump trucks. The ABC should be compacted to at least 98 percent of its Modified Proctor maximum dry unit weight per ASTM D1557 or AASHTO T180 (as modified by NCDOT), provided nuclear density testing is performed. Otherwise, at least 100% compaction is recommended. To confirm that the specified degree of compaction is being obtained, field compaction testing should be performed in each ABC lift by the ECS’ representative. We recommend that compaction tests be performed at a minimum frequency of one test per 5,000 square feet per lift in pavement areas. Minimum Material Lift Thickness: The minimum lift thickness for asphalt surface course mix S9.5B is 1.0 inch and the maximum lift thickness for S9.5B is 1.5 inches. For sections with more than 1.5 inches of S9.5B surface asphalt, it should be placed in two lifts. Asphalt pavement S9.5B should be compacted to least 90.0 percent of the material’s specific gravity Gmm. Drainage: An important consideration with the design and construction of pavements is surface and subsurface drainage. Where standing water develops, either on the pavement surface or within the aggregate base course layer, softening of the subgrades and other problems related to the deterioration of the pavement can be expected. This is particularly important at the site due to the moisture sensitive near-surface soils. Furthermore, good drainage should help reduce the possibility of the subgrade materials becoming saturated during the normal service period of the pavement. Tidal Wave Auto Spa - Wilmington February 25, 2022 ECS Project No. 22:31390 Page 10 5.0 SITE CONSTRUCTION RECOMMENDATIONS 5.1 SUBGRADE PREPARATION 5.1.1 Stripping and Grubbing The subgrade preparation should consist of stripping vegetation, rootmat, topsoil, existing fill, existing foundations, existing pavements, and soft or loose materials from the 10-foot expanded building and 5- foot expanded pavement limits. The soundings and borings performed in “undisturbed” areas of the site contained an observed thickness of approximately 2 to 6 inches of topsoil. Deeper topsoil or organic laden soils may be present in wet, low-lying, and poorly drained areas. ECS should be retained to verify that topsoil, existing foundations, and substandard surficial materials have been removed prior to the placement of Structural Fill or construction of structures. 5.1.2 Proofrolling Prior to fill placement or other construction on subgrades, the subgrades should be evaluated by an ECS field technician. The exposed subgrade should be proofrolled with construction equipment having a minimum axle load of 10 tons [e.g. tandem-axle dump truck loaded to capacity]. Proofrolling should be traversed in two perpendicular directions with overlapping passes of the vehicle under the observation of an ECS technician. This procedure is intended to assist in identifying localized yielding materials. Where proofrolling identifies areas that are unsteady or “pumping” subgrade those areas should be repaired prior to the placement of subsequent Structural Fill or other construction materials. Methods of stabilization include undercutting and moisture conditioning. The situation should be discussed with ECS to determine the appropriate procedure. Test pits may be excavated to explore the shallow subsurface materials to help in determining the cause of the observed unsteady materials, and to assist in the evaluation of appropriate remedial actions to stabilize the subgrade. Due to the near surface loose sands encountered in the hand auger borings, in-place densification should be anticipated to be performed in the vicinity of the borings, K-1 and K-4, prior to construction of pavements or placement of Structural Fill. 5.2 EARTHWORK OPERATIONS 5.2.1 Structural Fill Prior to placement of Structural Fill, bulk samples (about 50 pounds) of on-site and/or off-site borrow should be submitted to ECS for laboratory testing, which typically include Atterberg limits, natural moisture content, grain-size distribution, and moisture-density relationships (i.e., Proctors) for compaction. Import materials should be tested prior to being hauled to the site to determine if they meet project specifications. Alternatively, Proctor data from other accredited laboratories can be submitted if the test results are within the last 90 days. Tidal Wave Auto Spa - Wilmington February 25, 2022 ECS Project No. 22:31390 Page 11 Structural Fill Materials: Materials selected for use as Structural Fill should consist of inorganic soils with the following engineering properties and compaction requirements. STRUCTURAL FILL INDEX PROPERTIES Subject Property Building and Pavement Areas LL < 40, PI<10 Max. Particle Size 3 inches Fines Content Max. 20 % < #200 sieve Max. organic content 5% by dry weight STRUCTURAL FILL COMPACTION REQUIREMENTS Subject Requirement Compaction Standard Standard Proctor, ASTM D698 Required Compaction 98% of Max. Dry Density Dry Unit Weight >100 pcf Moisture Content -2 to +2 % points of the soil’s optimum value Loose Thickness 8 inches prior to compaction On-Site Borrow Suitability: Natural deposits of possible fill material are present on the site. The on-site sands (SM, SP) in the upper 10 feet across the site with fines contents less than 20 percent should meet the recommendations for re-use as Structural Fill. Fill Placement: Fill materials should not be placed on frozen soils, on frost-heaved soils, and/or on excessively wet soils. Borrow fill materials should not contain frozen materials at the time of placement, and frozen or frost-heaved soils should be removed prior to placement of Structural Fill or other fill soils and aggregates. Excessively wet soils or aggregates should be scarified, aerated, and moisture conditioned. 5.3 FOUNDATION AND SLAB OBSERVATIONS Protection of Foundation Excavations: Exposure to the environment may weaken the soils at the footing bearing level if the foundation excavations remain open for too long a time. Therefore, foundation concrete should be placed the same day that excavations are made. If the bearing soils are softened by surface water intrusion or exposure, the softened soils must be removed from the foundation excavation bottom immediately prior to placement of concrete. If the excavation must remain open overnight, or if rainfall becomes imminent while the bearing soils are exposed, a 1 to 3-inch thick “mud mat” of “lean” concrete should be placed on the bearing soils before the placement of reinforcing steel. Footing Subgrade Observations: A majority of the soils encountered on site at the foundation bearing elevation are anticipated to be adequate for support of the proposed structure. It is important to have ECS observe the foundation subgrade prior to placing foundation concrete, to confirm the bearing soils are what was anticipated. Slab Subgrade Verification: Prior to placement of a drainage layer, the subgrade should be prepared in accordance with the recommendations found in Section 5.1.2 Proofrolling. Tidal Wave Auto Spa - Wilmington February 25, 2022 ECS Project No. 22:31390 Page 12 5.4 UTILITY INSTALLATIONS Utility Subgrades: The soils encountered in our exploration are expected to be generally adequate for support of utility pipes. The pipe subgrades should be observed and probed for stability by ECS. Loose or unsteady materials encountered should be removed and replaced with compacted Structural Fill, or pipe stone bedding material. Utility Backfilling: The granular bedding material (AASHTO #57 stone) should be 4 inches thick, but not less than that specified by the civil engineer’s project drawings and specifications. We recommend that the bedding materials be placed up to the springline of the pipe. Fill placed for support of the utilities, as well as backfill over the utilities, should meets the requirements for Structural Fill and fill placement. Excavation Safety: Excavations and slopes should be constructed and maintained in accordance with OSHA excavation safety standards. The contractor is solely responsible for designing, constructing, and maintaining steady temporary excavations and slopes. The contractor’s responsible person, as defined in 29 CFR Part 1926, should evaluate the soil exposed in the excavations as part of the contractor’s safety procedures. The slope height, slope inclination, or excavation depth, including utility trench excavation depth, should not exceed those specified in local, state, and federal safety regulations. ECS is providing this information solely as a service to our client. ECS is not assuming responsibility for construction site safety or the contractor’s activities; such responsibility is not being implied and should not be inferred. Tidal Wave Auto Spa - Wilmington February 25, 2022 ECS Project No. 22:31390 Page 13 6.0 CLOSING ECS has prepared this report to guide the geotechnical-related design and construction aspects of the project. We performed these services in accordance with the standard of care expected of professionals in the industry performing similar services on projects of like size and complexity at this time in the region. No other representation, expressed or implied, and no warranty or guarantee is included or intended in this report. The description of the proposed project is based on information provided to ECS by Mr. Brian Braun, PE of Advanced Engineering Services, LLC. If this information is untrue or changes, either because of our interpretation of the documents provided or site or design changes that may occur later, ECS should be contacted so we can review our recommendations and provide additional or alternate recommendations that reflect the proposed construction. We recommend that ECS review the project plans and specifications so we can confirm that those plans/specifications are in accordance with the recommendations of this geotechnical report. Field observations and quality assurance testing during earthwork and foundation installation are an extension of, and integral to, the geotechnical design. We recommend that ECS be retained to apply our expertise throughout the geotechnical phases of construction, and to provide consultation and recommendation should issues arise. ECS is not responsible for the conclusions, opinions, or recommendations of others based on the data in this report. APPENDIX A – Diagrams & Reports Site Location Diagram Exploration Location Diagram Service Layer Credits: Esri, HERE, Garmin, (c) OpenStreetMap contributors ² ADVANCED ENGINEERING SERVICES, LLC TIDAL WAVE AUTO SPA - WILMINGTON 8005-8015 MARKET STREET, WILMINGTON, NC SITE LOCATION DIAGRAM 0 600300Feet 2/25/2022 ENGINEER SCALE 22:31390 1 OF 2 PROJECT NO. SHEET DATE WEG AS NOTED Service Layer Credits: Esri, HERE, Garmin, (c) OpenStreetMap contributors ² Legend Approximate Hand Auger Boring with Kessler DCP Test Location Approximate CPT Sounding Location ADVANCED ENGINEERING SERVICES, LLC TIDAL WAVE AUTO SPA - WILMINGTON 8005-8015 MARKET STREET, WILMINGTON, NC BORING LOCATION DIAGRAM 0 12060Feet 2/25/2022 ENGINEER SCALE 22:31390 2 OF 2 PROJECT NO. SHEET DATE WEG AS NOTED APPENDIX B – Field Operations Reference Notes for CPT Sounding Logs Cone Penetration Test Sounding Logs (S-1 through S-3) Reference Notes for Boring Logs Hand Auger Boring Logs (K-1 through K-4) Kessler DCP Test Data REFERENCE NOTES FOR CONE PENETRATION TEST (CPT) SOUNDINGS In the CPT sounding procedure (ASTM-D-5778), an electronically instrumented cone penetrometer is hydraulically advanced through soil to measure point resistance (qc), pore water pressure (u2), and sleeve friction (fs). These values are recorded continuously as the cone is pushed to the desired depth. CPT data is corrected for depth and used to estimate soil classifications and intrinsic soil parameters such as angle of internal friction, preconsolidation pressure, and undrained shear strength. The graphs below represent one of the accepted methods of CPT soil behavior classification (Robertson, 1990). 1. Sensitive, Fine Grained 6. Clean Sands to Silty Sands 2. Organic Soils-Peats 7. Gravelly Sand to Sand 3. Clays; Clay to Silty Clay 8. Very Stiff Sand to Clayey Sand 4. Clayey Silt to Silty Clay 9. Very Stiff Fine Grained 5. Silty Sand to Sandy Silt The following table presents a correlation of corrected cone tip resistance (q ) to soil consistency or relative density: SAND SILT/CLAY Corrected Cone Tip Resistance (q ) (tsf) Relative Density Corrected Cone Tip Resistance (q ) (tsf) Relative Density <20 Very Loose <5 Very Soft 20-40 Loose 5-10 Soft 40-120 Medium Dense 10-15 15-30 Stiff 120-200 Dense 30-45 Very Stiff >200 Very Dense 45-60 Hard >60 Very Hard Pore Pressure Ratio, Bq Co n e R e s i s t a n c e , Q t Co n e R e s i s t a n c e , Q t Friction Ratio, Fr (%) SUBSURFACE EXPLORATION PROCEDURE: CONE PENETRATION TESTING (CPT) ASTM D 5778 In the CPT sounding procedure, an electronically instrumented cone penetrometer is hydraulically advanced through soil to measure point resistance (qc), pore water pressure (U2), and sleeve fricon (fs). These values are recorded connuously as the cone is pushed to the desired depth. CPT data is corrected for depth and used to esmate soil classificaons and intrinsic soil parameters such as angle of internal fricon, pre-consolidaon pressure, and undrained shear strength. Involves the direct push of an electronically instrumented cone penetrometer* through the soil Values are recorded connuously CPT data is corrected and correlated to soil parameters *CPT Penetrometer Size May Vary CPT Procedure: Project: Tidal Wave Auto Spa - Wilmington ECS Southeast, LLP 6714 Netherlands Drive Wilmington, NC 28403 ECS Project # 22-31390 Total depth: 19.85 ft, Date: 2/17/2022 Wilmington, New Hanover County, North Carolina Cone Operator: Devon Highfield CPT: S-1 Location: Cone resistance Tip resistance (tsf) 15010050 De p t h ( f t ) 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 Cone resistance Sleeve friction Friction (tsf) 1.510.5 De p t h ( f t ) 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 Sleeve friction Pore pressure u Pressure (psi) 6040200 De p t h ( f t ) 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 Pore pressure u SPT N60 N60 (blows/ft) 6040200 De p t h ( f t ) 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 SPT N60 Norm. Soil Behaviour Type SBTn (Robertson 1990) 1612840 De p t h ( f t ) 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 Norm. Soil Behaviour Type Sand & silty sand Silty sand & sandy silt Sand & silty sand Silty sand & sandy silt Clay & silty clay Silty sand & sandy silt Clay & silty clay Clay Clay & silty clay Silty sand & sandy silt Sand & silty sand CPeT-IT v.2.0.1.16 - CPTU data presentation & interpretation software - Report created on: 2/24/2022, 4:54:16 PM 0 Project file: D:\CPT\31390 - Tidal Wave\sounding_files.cpt Project: Tidal Wave Auto Spa - Wilmington ECS Southeast, LLP 6714 Netherlands Drive Wilmington, NC 28403 ECS Project # 22-31390 Total depth: 33.46 ft, Date: 2/17/2022 Wilmington, New Hanover County, North Carolina Cone Operator: Devon Highfield CPT: S-2 Location: Cone resistance Tip resistance (tsf) 5000 De p t h ( f t ) 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 Cone resistance Sleeve friction Friction (tsf) 210 De p t h ( f t ) 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 Sleeve friction Pore pressure u Pressure (psi) 500 De p t h ( f t ) 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 Pore pressure u SPT N60 N60 (blows/ft) 6040200 De p t h ( f t ) 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 SPT N60 Seismic Velocity Velocity (ft/s) 5000 De p t h 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 Seismic Velocity Norm. Soil Behaviour Type SBTn (Robertson 1990) 1612840 De p t h ( f t ) 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Norm. Soil Behaviour Type Sand & silty sand Silty sand & sandy silt Clay & silty clay Clay Clay & silty clay Clay Clay & silty clay Clay Clay & silty clay Silty sand & sandy silt Sand & silty sand Silty sand & sandy silt Clay & silty clay Clay & silty clay Sand & silty sand Sand Clay CPeT-IT v.2.0.1.16 - CPTU data presentation & interpretation software - Report created on: 2/24/2022, 4:54:47 PM 0 Project file: D:\CPT\31390 - Tidal Wave\sounding_files.cpt Project: Tidal Wave Auto Spa - Wilmington ECS Southeast, LLP 6714 Netherlands Drive Wilmington, NC 28403 ECS Project # 22-31390 Total depth: 9.84 ft, Date: 2/17/2022 Wilmington, New Hanover County, North Carolina Cone Operator: Devon Highfield CPT: S-3 Location: Cone resistance Tip resistance (tsf) 80604020 De p t h ( f t ) 9.5 9 8.5 8 7.5 7 6.5 6 5.5 5 4.5 4 3.5 3 2.5 2 1.5 1 0.5 Cone resistance Sleeve friction Friction (tsf) 0.60.50.40.30.2 De p t h ( f t ) 9.5 9 8.5 8 7.5 7 6.5 6 5.5 5 4.5 4 3.5 3 2.5 2 1.5 1 0.5 Sleeve friction Pore pressure u Pressure (psi) 10.50-0.5 De p t h ( f t ) 9.5 9 8.5 8 7.5 7 6.5 6 5.5 5 4.5 4 3.5 3 2.5 2 1.5 1 0.5 Pore pressure u SPT N60 N60 (blows/ft) 6040200 De p t h ( f t ) 9 8 7 6 5 4 3 2 1 SPT N60 Norm. Soil Behaviour Type SBTn (Robertson 1990) 181614121086420 De p t h ( f t ) 9.5 9 8.5 8 7.5 7 6.5 6 5.5 5 4.5 4 3.5 3 2.5 2 1.5 1 0.5 Norm. Soil Behaviour Type Sand & silty sand Silty sand & sandy silt Clay & silty clay Sand & silty sand CPeT-IT v.2.0.1.16 - CPTU data presentation & interpretation software - Report created on: 2/24/2022, 4:55:18 PM 0 Project file: D:\CPT\31390 - Tidal Wave\sounding_files.cpt REFERENCE NOTES FOR BORING LOGS MATERIAL1,2 1Classifications and symbols per ASTM D 2488-17 (Visual-Manual Procedure) unless noted otherwise. 2To be consistent with general practice, “POORLY GRADED” has been removed from GP, GP-GM, GP-GC, SP, SP-SM, SP-SC soil types on the boring logs. 3Non-ASTM designations are included in soil descriptions and symbols along with ASTM symbol [Ex: (SM-FILL)]. 4Typically estimated via pocket penetrometer or Torvane shear test and expressed in tons per square foot (tsf). 5Standard Penetration Test (SPT) refers to the number of hammer blows (blow count) of a 140 lb. hammer falling 30 inches on a 2 inch OD split spoon sampler required to drive the sampler 12 inches (ASTM D 1586). “N-value” is another term for “blow count” and is expressed in blows per foot (bpf). SPT correlations per 7.4.2 Method B and need to be corrected if using an auto hammer. 6The water levels are those levels actually measured in the borehole at the times indicated by the symbol. The measurements are relatively reliable when augering, without adding fluids, in granular soils. In clay and cohesive silts, the determination of water levels may require several days for the water level to stabilize.In such cases, additional methods of measurement are generally employed. 7Minor deviation from ASTM D 2488-17 Note 14. 8Percentages are estimated to the nearest 5% per ASTM D 2488-17. Reference Notes for Boring Logs (09-02-2021).doc © 2021 ECS Corporate Services, LLC. All Rights Reserved COHESIVE SILTS & CLAYS UNCONFINED COMPRESSIVE STRENGTH, QP4 <0.25 0.25 - <0.50 0.50 - <1.00 1.00 - <2.00 2.00 - <4.00 4.00 - 8.00 >8.00 SPT5 (BPF) CONSISTENCY7 (COHESIVE) GRAVELS, SANDS & NON-COHESIVE SILTS SPT5 DENSITY <5 5 - 10 11 - 30 31 - 50 >50 Very Loose Loose Medium Dense Dense Very Dense WATER LEVELS6 RELATIVE AMOUNT7 Trace With Adjective (ex: “Silty”) COARSE GRAINED (%)8 <5 FINE GRAINED (%)8 <5 DRILLING SAMPLING SYMBOLS & ABBREVIATIONS PARTICLE SIZE IDENTIFICATION DESIGNATION PARTICLE SIZES Hollow Stem Auger Power Auger (no sample) Bulk Sample of Cuttings Wash Sample Shelby Tube Sampler Split Spoon Sampler Rock Quality Designation % Rock Sample Recovery % Rock Core, NX, BX, AX Rock Bit Drilling Pressuremeter TestSS ST WS BS PA HSA RQD PM RD RC REC Boulders Cobbles Gravel: Sand: Silt & Clay (“Fines”) Fine Medium Coarse Fine Coarse 0.074 mm to 0.425 mm (No. 200 to No. 40 sieve) <0.074 mm (smaller than a No. 200 sieve) 0.425 mm to 2.00 mm (No. 40 to No. 10 sieve) 2.00 mm to 4.75 mm (No. 10 to No. 4 sieve) 4.75 mm to 19 mm (No. 4 sieve to ¾ inch) ¾ inch to 3 inches (19 mm to 75 mm) 3 inches to 12 inches (75 mm to 300 mm) 12 inches (300 mm) or larger >50 31 - 50 16 - 30 9 - 15 5 - 8 2 - 4 <2 Very Hard Hard Very Stiff Stiff Firm Soft Very Soft ASPHALT CONCRETE GRAVEL TOPSOIL VOID BRICK AGGREGATE BASE COURSE GW GP GM GC SW SP SM SC ML MH CL CH OL OH PT WELL-GRADED GRAVEL gravel-sand mixtures, little or no fines POORLY-GRADED GRAVEL gravel-sand mixtures, little or no fines SILTY GRAVEL gravel-sand-silt mixtures CLAYEY GRAVEL gravel-sand-clay mixtures WELL-GRADED SAND gravelly sand, little or no fines POORLY-GRADED SAND gravelly sand, little or no fines SILTY SAND sand-silt mixtures CLAYEY SAND sand-clay mixtures SILT non-plastic to medium plasticity ELASTIC SILT high plasticity LEAN CLAY low to medium plasticity FAT CLAY high plasticity ORGANIC SILT or CLAY non-plastic to low plasticity ORGANIC SILT or CLAY high plasticity PEAT highly organic soils WL (First Encountered) WL (Completion) WL (Seasonal High Water) WL (Stabilized) FILL POSSIBLE FILL PROBABLE FILL ROCK FILL AND ROCK 25 - 45 10 - 20 30 - 45 10 - 25 DE PTH ( F T ) 5 WATE R L E V E L S EL E VATI O N ( F T ) DESCRIPTION OF MATERIAL Topsoil Thickness[4.00"] (SP) FINE TO MEDIUM SAND, gray to tan, moist (SM) SILTY FINE TO MEDIUM SAND, brown, moist END OF DRILLING AT 4.0 FT EXCAVATI O N E F FORT DC P SA M P L E N U M B E R FI N ES CON T E N T (% ) MO I S T U R E CON T E N T (% ) CLIENT:PROJECT NO.: Advanced Engineering Services, LLC 22:31390 PROJECT NAME:HAND AUGER NO.: Tidal Wave Auto Spa -Wilmington K-01 SITE LOCATION: 8005 Market Street, Wilmington, North Carolina 28411 NORTHING:EASTING: SHEET: 1 of 1 SURFACE ELEVATION: STATION: REMARKS: THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDRY LINES BETWEEN SOIL TYPES. IN-SITU THE TRANSITION MAY BE GRADUAL EXCAVATION EFFORT: E -EASY M -MEDIUM D -DIFFICULT VD -VERY DIFFICULT WL (First Encountered)WL (Seasonal High)ECS REP:DATE COMPLETED:UNITS:CAVE-IN-DEPTH: WL (CompleƟon)Feb 11 2022 English HAND AUGER LOG DCP TEST DATA Project:Tidal Wave Auto Spa - Wilmington Date: 11-Feb-22 Location: K-1 Soil Type(s):SAND (SP, SM) No. of Accumulative Type of Blows Penetration Hammer (mm) 0 0 1 3 203.2 1 5 368.3 1 5 515.62 1 5 650.24 1 5 754.38 1 5 866.14 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 5 10 15 20 25 30 35 40 0.1 1.0 10.0 100.0 0 127 254 381 508 635 762 889 1016 0.1 1.0 10.0 100.0 DE P T H , i n . CBR DE P T H , m m 10.1 lbs. 17.6 lbs. Both hammers used Soil Type CH CL All other soils Hammer 0 127 254 381 508 635 762 889 1016 0 14 28 42 56 69 83 0 5 10 15 20 25 30 35 40 0 2000 4000 6000 8000 10000 12000 DE P T H , m m BEARING CAPACITY, psi DE P T H , i n BEARING CAPACITY, psf Based on approximate interrelationships of CBR and Bearing values (Design of Concrete Airport Pavement, Portland Cement Association, page 8, 1955) DE PTH ( F T ) 5 WATE R L E V E L S EL E VATI O N ( F T ) DESCRIPTION OF MATERIAL Topsoil Thickness[6.00"] (SP) FINE TO MEDIUM SAND, gray, moist (SM) SILTY FINE TO MEDIUM SAND, brown, moist END OF DRILLING AT 4.0 FT EXCAVATI O N E F FORT DC P SA M P L E N U M B E R FI N ES CON T E N T (% ) MO I S T U R E CON T E N T (% ) CLIENT:PROJECT NO.: Advanced Engineering Services, LLC 22:31390 PROJECT NAME:HAND AUGER NO.: Tidal Wave Auto Spa -Wilmington K-02 SITE LOCATION: 8005 Market Street, Wilmington, North Carolina 28411 NORTHING:EASTING: SHEET: 1 of 1 SURFACE ELEVATION: STATION: REMARKS: THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDRY LINES BETWEEN SOIL TYPES. IN-SITU THE TRANSITION MAY BE GRADUAL EXCAVATION EFFORT: E -EASY M -MEDIUM D -DIFFICULT VD -VERY DIFFICULT WL (First Encountered)WL (Seasonal High)ECS REP:DATE COMPLETED:UNITS:CAVE-IN-DEPTH: WL (CompleƟon)Feb 11 2022 English HAND AUGER LOG DCP TEST DATA Project:Tidal Wave Auto Spa - Wilmington Date: 11-Feb-22 Location: K-2 Soil Type(s):SAND (SP, SM) No. of Accumulative Type of Blows Penetration Hammer (mm) 0 0 1 5 111.76 1 5 215.9 1 5 302.26 1 5 381 1 5 457.2 1 10 604.52 1 10 751.84 1 7 883.92 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 5 10 15 20 25 30 35 40 0.1 1.0 10.0 100.0 0 127 254 381 508 635 762 889 1016 0.1 1.0 10.0 100.0 DE P T H , i n . CBR DE P T H , m m 10.1 lbs. 17.6 lbs. Both hammers used Soil Type CH CL All other soils Hammer 0 127 254 381 508 635 762 889 1016 0 14 28 42 56 69 83 0 5 10 15 20 25 30 35 40 0 2000 4000 6000 8000 10000 12000 DE P T H , m m BEARING CAPACITY, psi DE P T H , i n BEARING CAPACITY, psf Based on approximate interrelationships of CBR and Bearing values (Design of Concrete Airport Pavement, Portland Cement Association, page 8, 1955) DE PTH ( F T ) 5 WATE R L E V E L S EL E VATI O N ( F T ) DESCRIPTION OF MATERIAL Topsoil Thickness[6.00"] (SM) SILTY FINE TO MEDIUM SAND, gray to brown, moist END OF DRILLING AT 4.0 FT EXCAVATI O N E F FORT DC P SA M P L E N U M B E R FI N ES CON T E N T (% ) MO I S T U R E CON T E N T (% ) CLIENT:PROJECT NO.: Advanced Engineering Services, LLC 22:31390 PROJECT NAME:HAND AUGER NO.: Tidal Wave Auto Spa -Wilmington K-03 SITE LOCATION: 8005 Market Street, Wilmington, North Carolina 28411 NORTHING:EASTING: SHEET: 1 of 1 SURFACE ELEVATION: STATION: REMARKS: THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDRY LINES BETWEEN SOIL TYPES. IN-SITU THE TRANSITION MAY BE GRADUAL EXCAVATION EFFORT: E -EASY M -MEDIUM D -DIFFICULT VD -VERY DIFFICULT WL (First Encountered)WL (Seasonal High)ECS REP:DATE COMPLETED:UNITS:CAVE-IN-DEPTH: WL (CompleƟon)Feb 11 2022 English HAND AUGER LOG DCP TEST DATA Project:Tidal Wave Auto Spa - Wilmington Date: 11-Feb-22 Location: K-3 Soil Type(s):SAND (SM) No. of Accumulative Type of Blows Penetration Hammer (mm) 0 0 1 5 116.84 1 5 215.9 1 5 358.14 1 5 467.36 1 5 546.1 1 5 601.98 1 5 655.32 1 5 698.5 1 5 734.06 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 5 10 15 20 25 30 35 40 0.1 1.0 10.0 100.0 0 127 254 381 508 635 762 889 1016 0.1 1.0 10.0 100.0 DE P T H , i n . CBR DE P T H , m m 10.1 lbs. 17.6 lbs. Both hammers used Soil Type CH CL All other soils Hammer 0 127 254 381 508 635 762 889 1016 0 14 28 42 56 69 83 0 5 10 15 20 25 30 35 40 0 2000 4000 6000 8000 10000 12000 DE P T H , m m BEARING CAPACITY, psi DE P T H , i n BEARING CAPACITY, psf Based on approximate interrelationships of CBR and Bearing values (Design of Concrete Airport Pavement, Portland Cement Association, page 8, 1955) DE PTH ( F T ) 5 WATE R L E V E L S EL E VATI O N ( F T ) DESCRIPTION OF MATERIAL Topsoil Thickness[6.00"] (SP) FINE TO MEDIUM SAND, gray, moist (SM) SILTY FINE TO MEDIUM SAND, brown, moist END OF DRILLING AT 4.0 FT EXCAVATI O N E F FORT DC P SA M P L E N U M B E R FI N ES CON T E N T (% ) MO I S T U R E CON T E N T (% ) CLIENT:PROJECT NO.: Advanced Engineering Services, LLC 22:31390 PROJECT NAME:HAND AUGER NO.: Tidal Wave Auto Spa -Wilmington K-04 SITE LOCATION: 8005 Market Street, Wilmington, North Carolina 28411 NORTHING:EASTING: SHEET: 1 of 1 SURFACE ELEVATION: STATION: REMARKS: THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDRY LINES BETWEEN SOIL TYPES. IN-SITU THE TRANSITION MAY BE GRADUAL EXCAVATION EFFORT: E -EASY M -MEDIUM D -DIFFICULT VD -VERY DIFFICULT WL (First Encountered)WL (Seasonal High)ECS REP:DATE COMPLETED:UNITS:CAVE-IN-DEPTH: WL (CompleƟon)Feb 11 2022 English HAND AUGER LOG DCP TEST DATA Project:Tidal Wave Auto Spa - Wilmington Date: 11-Feb-22 Location: K-4 Soil Type(s):SAND (SP, SM) No. of Accumulative Type of Blows Penetration Hammer (mm) 0 0 1 1 238.76 1 5 353.06 1 5 403.86 1 5 538.48 1 5 624.84 1 5 701.04 1 5 772.16 1 5 840.74 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 5 10 15 20 25 30 35 40 0.1 1.0 10.0 100.0 0 127 254 381 508 635 762 889 1016 0.1 1.0 10.0 100.0 DE P T H , i n . CBR DE P T H , m m 10.1 lbs. 17.6 lbs. Both hammers used Soil Type CH CL All other soils Hammer 0 127 254 381 508 635 762 889 1016 0 14 28 42 56 69 83 0 5 10 15 20 25 30 35 40 0 2000 4000 6000 8000 10000 12000 DE P T H , m m BEARING CAPACITY, psi DE P T H , i n BEARING CAPACITY, psf Based on approximate interrelationships of CBR and Bearing values (Design of Concrete Airport Pavement, Portland Cement Association, page 8, 1955) APPENDIX C – Supplemental Report Documents GBA Document Geotechnical-Engineering Report Important Information about This Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes. While you cannot eliminate all such risks, you can manage them. The following information is provided to help. The Geoprofessional Business Association (GBA) has prepared this advisory to help you – assumedly a client representative – interpret and apply this geotechnical-engineering report as effectively as possible. In that way, clients can benefit from a lowered exposure to the subsurface problems that, for decades, have been a principal cause of construction delays, cost overruns, claims, and disputes. If you have questions or want more information about any of the issues discussed below, contact your GBA-member geotechnical engineer. Active involvement in the Geoprofessional Business Association exposes geotechnical engineers to a wide array of risk-confrontation techniques that can be of genuine benefit for everyone involved with a construction project. Geotechnical-Engineering Services Are Performed for Specific Purposes, Persons, and ProjectsGeotechnical engineers structure their services to meet the specific needs of their clients. A geotechnical-engineering study conducted for a given civil engineer will not likely meet the needs of a civil-works constructor or even a different civil engineer. Because each geotechnical-engineering study is unique, each geotechnical-engineering report is unique, prepared solely for the client. Those who rely on a geotechnical-engineering report prepared for a different client can be seriously misled. No one except authorized client representatives should rely on this geotechnical-engineering report without first conferring with the geotechnical engineer who prepared it. And no one – not even you – should apply this report for any purpose or project except the one originally contemplated. Read this Report in FullCostly problems have occurred because those relying on a geotechnical-engineering report did not read it in its entirety. Do not rely on an executive summary. Do not read selected elements only. Read this report in full. You Need to Inform Your Geotechnical Engineer about ChangeYour geotechnical engineer considered unique, project-specific factors when designing the study behind this report and developing the confirmation-dependent recommendations the report conveys. A few typical factors include: • the client’s goals, objectives, budget, schedule, and risk-management preferences; • the general nature of the structure involved, its size, configuration, and performance criteria; • the structure’s location and orientation on the site; and • other planned or existing site improvements, such as retaining walls, access roads, parking lots, and underground utilities. Typical changes that could erode the reliability of this report include those that affect: • the site’s size or shape; • the function of the proposed structure, as when it’s changed from a parking garage to an office building, or from a light-industrial plant to a refrigerated warehouse; • the elevation, configuration, location, orientation, or weight of the proposed structure; • the composition of the design team; or • project ownership. As a general rule, always inform your geotechnical engineer of project changes – even minor ones – and request an assessment of their impact. The geotechnical engineer who prepared this report cannot accept responsibility or liability for problems that arise because the geotechnical engineer was not informed about developments the engineer otherwise would have considered. This Report May Not Be ReliableDo not rely on this report if your geotechnical engineer prepared it: • for a different client; • for a different project; • for a different site (that may or may not include all or a portion of the original site); or • before important events occurred at the site or adjacent to it; e.g., man-made events like construction or environmental remediation, or natural events like floods, droughts, earthquakes, or groundwater fluctuations. Note, too, that it could be unwise to rely on a geotechnical-engineering report whose reliability may have been affected by the passage of time, because of factors like changed subsurface conditions; new or modified codes, standards, or regulations; or new techniques or tools. If your geotechnical engineer has not indicated an “apply-by” date on the report, ask what it should be, and, in general, if you are the least bit uncertain about the continued reliability of this report, contact your geotechnical engineer before applying it. A minor amount of additional testing or analysis – if any is required at all – could prevent major problems. Most of the “Findings” Related in This Report Are Professional Opinions Before construction begins, geotechnical engineers explore a site’s subsurface through various sampling and testing procedures. Geotechnical engineers can observe actual subsurface conditions only at those specific locations where sampling and testing were performed. The data derived from that sampling and testing were reviewed by your geotechnical engineer, who then applied professional judgment to form opinions about subsurface conditions throughout the site. Actual sitewide-subsurface conditions may differ – maybe significantly – from those indicated in this report. Confront that risk by retaining your geotechnical engineer to serve on the design team from project start to project finish, so the individual can provide informed guidance quickly, whenever needed. This Report’s Recommendations Are Confirmation-DependentThe recommendations included in this report – including any options or alternatives – are confirmation-dependent. In other words, they are not final, because the geotechnical engineer who developed them relied heavily on judgment and opinion to do so. Your geotechnical engineer can finalize the recommendations only after observing actual subsurface conditions revealed during construction. If through observation your geotechnical engineer confirms that the conditions assumed to exist actually do exist, the recommendations can be relied upon, assuming no other changes have occurred. The geotechnical engineer who prepared this report cannot assume responsibility or liability for confirmation-dependent recommendations if you fail to retain that engineer to perform construction observation. This Report Could Be MisinterpretedOther design professionals’ misinterpretation of geotechnical-engineering reports has resulted in costly problems. Confront that risk by having your geotechnical engineer serve as a full-time member of the design team, to: • confer with other design-team members, • help develop specifications, • review pertinent elements of other design professionals’ plans and specifications, and • be on hand quickly whenever geotechnical-engineering guidance is needed. You should also confront the risk of constructors misinterpreting this report. Do so by retaining your geotechnical engineer to participate in prebid and preconstruction conferences and to perform construction observation. Give Constructors a Complete Report and GuidanceSome owners and design professionals mistakenly believe they can shift unanticipated-subsurface-conditions liability to constructors by limiting the information they provide for bid preparation. To help prevent the costly, contentious problems this practice has caused, include the complete geotechnical-engineering report, along with any attachments or appendices, with your contract documents, but be certain to note conspicuously that you’ve included the material for informational purposes only. To avoid misunderstanding, you may also want to note that “informational purposes” means constructors have no right to rely on the interpretations, opinions, conclusions, or recommendations in the report, but they may rely on the factual data relative to the specific times, locations, and depths/elevations referenced. Be certain that constructors know they may learn about specific project requirements, including options selected from the report, only from the design drawings and specifications. Remind constructors that they may perform their own studies if they want to, and be sure to allow enough time to permit them to do so. Only then might you be in a position to give constructors the information available to you, while requiring them to at least share some of the financial responsibilities stemming from unanticipated conditions. Conducting prebid and preconstruction conferences can also be valuable in this respect. Read Responsibility Provisions Closely Some client representatives, design professionals, and constructors do not realize that geotechnical engineering is far less exact than other engineering disciplines. That lack of understanding has nurtured unrealistic expectations that have resulted in disappointments, delays, cost overruns, claims, and disputes. To confront that risk, geotechnical engineers commonly include explanatory provisions in their reports. Sometimes labeled “limitations,” many of these provisions indicate where geotechnical engineers’ responsibilities begin and end, to help others recognize their own responsibilities and risks. Read these provisions closely. Ask questions. Your geotechnical engineer should respond fully and frankly. Geoenvironmental Concerns Are Not Covered The personnel, equipment, and techniques used to perform an environmental study – e.g., a “phase-one” or “phase-two” environmental site assessment – differ significantly from those used to perform a geotechnical-engineering study. For that reason, a geotechnical- engineering report does not usually relate any environmental findings, conclusions, or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Unanticipated subsurface environmental problems have led to project failures. If you have not yet obtained your own environmental information, ask your geotechnical consultant for risk-management guidance. As a general rule, do not rely on an environmental report prepared for a different client, site, or project, or that is more than six months old. Obtain Professional Assistance to Deal with Moisture Infiltration and Mold While your geotechnical engineer may have addressed groundwater, water infiltration, or similar issues in this report, none of the engineer’s services were designed, conducted, or intended to prevent uncontrolled migration of moisture – including water vapor – from the soil through building slabs and walls and into the building interior, where it can cause mold growth and material-performance deficiencies. Accordingly, proper implementation of the geotechnical engineer’s recommendations will not of itself be sufficient to prevent moisture infiltration. Confront the risk of moisture infiltration by including building-envelope or mold specialists on the design team. Geotechnical engineers are not building-envelope or mold specialists. Copyright 2016 by Geoprofessional Business Association (GBA). Duplication, reproduction, or copying of this document, in whole or in part, by any means whatsoever, is strictly prohibited, except with GBA’s specific written permission. Excerpting, quoting, or otherwise extracting wording from this document is permitted only with the express written permission of GBA, and only for purposes of scholarly research or book review. Only members of GBA may use this document or its wording as a complement to or as an element of a report of any kind. Any other firm, individual, or other entity that so uses this document without being a GBA member could be committing negligent Telephone: 301/565-2733 e-mail: info@geoprofessional.org www.geoprofessional.org August 24, 2022 Mr. Alex Perry Tidal Wave Auto Spa 124 East Thompson Street Thomaston, Georgia 30286 Reference: Report of Seasonal High Water Table Estimation and Infiltration Testing Tidal Wave Market Street Wilmington, New Hanover County, North Carolina ECS Project No. 49.18254 Dear Mr. Perry: ECS Southeast, LLP (ECS) recently conducted a seasonal high water table (SHWT) estimation and infiltration testing within the stormwater control measure (SCM) area(s) at 8005 Market Street in Wilmington, New Hanover County, North Carolina. This letter, with attachments, is the report of our testing. Field Testing On August 22, 2022, ECS conducted an exploration of the subsurface soil conditions, in accordance with the NCDEQ Stormwater Design Manual section A-2, at two requested locations shown on the attached Boring Location Plan (Figure 1). ECS used GPS equipment in order to determine the boring locations. The purpose of this exploration was to obtain subsurface information of the in situ soils for the SCM area(s). ECS explored the subsurface soil conditions by advancing one hand auger boring into the existing ground surface at each of the requested boring locations. ECS visually classified the subsurface soils and obtained representative samples of each soil type encountered. ECS also recorded the SHWT elevation observed at the time of the hand auger borings. The attached Infiltration Testing Form provides a summary of the subsurface conditions encountered at the hand auger boring locations. The SHWT elevation was estimated at the boring locations below the existing grade elevation. A summary of the findings are as follows: Location SHWT I-1 24 inches I-2 20 inches ECS has conducted three infiltration tests utilizing a compact constant head permeameter near the hand auger borings in order to estimate the infiltration rate for the subsurface soils. Infiltration tests are typically conducted at two feet above the SHWT or in the most restrictive soil horizon. Tests in clayey conditions are conducted for durations of up to 30 minutes. If a more precise hydraulic conductivity value is desired for these locations, then ECS recommends collecting samples and performing laboratory permeability testing. Report of SHWT Estimation and Infiltration Testing Tidal Wave Market Street Wilmington, New Hanover County, North Carolina ECS Project No. 49.18254 August 24, 2022 2 Field Test Results Below is a summary of the infiltration test results: Location Description Depth Inches/ hour I-1 Black/brown silty SAND (Hardpan) 29 inches 0.10 I-2 Black/brown silty SAND (Hardpan) 30 inches 0.10 I-2A Dark gray fine-medium SAND 12 inches 18.85 Infiltration rates and SHWT may vary within the proposed site due to changes in elevation, soil classification and subsurface conditions. ECS recommends that a licensed surveyor provide the elevations of the boring locations. ECS conducted an additional test, I-2A, to demonstrate a change in hydraulic conductivity with the change in soil classification. This test was conducted near the surface elevation in case pervious pavement is designed. Closure ECS’s analysis of the site has been based on our understanding of the site, the project information provided to us, and the data obtained during our exploration. If the project information provided to us is changed, please contact us so that our recommendations can be reviewed and appropriate revisions provided, if necessary. The discovery of any site or subsurface conditions during construction which deviate from the data outlined in this exploration should be reported to us for our review, analysis and revision of our recommendations, if necessary. The assessment of site environmental conditions for the presence of pollutants in the soil and groundwater of the site is beyond the scope of this geotechnical exploration. ECS appreciates the opportunity to provide our services to you on this project. If you have any questions concerning this report or this project, please contact us. Respectfully, ECS SOUTHEAST, LLP K. Brooks Wall W. Brandon Fulton, PSC, PWS, LSS Project Manager Environmental Department Manager bwall@ecslimited.com bfulton@ecslimited.com 910-686-9114 704-525-5152 Attachments: Figure 1 - Boring Location Plan Infiltration Testing Form GBA Document APPROXIMATE BORING LOCATIONS SCALE SHOWN ABOVE Tidal Wave Market StreetWilmington, New Hanover County, North Carolina ECS Project # 49.18254August 22, 2022JF Figure 1–Boring Location Plan Provided by: Google Earth I-1 I-2 N W S E N W S E Infiltration Testing Form Tidal Wave Market Street Wilmington, New Hanover County, North Carolina ECS Project No. 49.18254 August 22, 2022 Location Depth USCS Soil Description I-1 0-20” SP Dark gray fine-medium SAND 20”-27” SM Black/brown silty SAND (Hardpan) Seasonal High Water Table was estimated to be at 24 inches below the existing grade elevation. Test was conducted at 29 inches below existing grade elevation Infiltration Rate: 0.10 inches per hour Location Depth USCS Soil Description I-2 0-20” SP Dark gray fine-medium SAND 20”-48” SM Black/brown silty SAND (Hardpan) Seasonal High Water Table was estimated to be at 20 inches below the existing grade elevation. I-2 test was conducted at 30 inches below existing grade elevation Infiltration Rate: 0.10 inches per hour I-2A test was conducted at 12 inches below existing grade elevation Infiltration Rate: 18.85 inches per hour Geotechnical-Engineering Report Important Information about This Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes. While you cannot eliminate all such risks, you can manage them. The following information is provided to help. The Geoprofessional Business Association (GBA) has prepared this advisory to help you – assumedly a client representative – interpret and apply this geotechnical-engineering report as effectively as possible. In that way, clients can benefit from a lowered exposure to the subsurface problems that, for decades, have been a principal cause of construction delays, cost overruns, claims, and disputes. If you have questions or want more information about any of the issues discussed below, contact your GBA-member geotechnical engineer. Active involvement in the Geoprofessional Business Association exposes geotechnical engineers to a wide array of risk-confrontation techniques that can be of genuine benefit for everyone involved with a construction project. Geotechnical-Engineering Services Are Performed for Specific Purposes, Persons, and ProjectsGeotechnical engineers structure their services to meet the specific needs of their clients. A geotechnical-engineering study conducted for a given civil engineer will not likely meet the needs of a civil-works constructor or even a different civil engineer. Because each geotechnical-engineering study is unique, each geotechnical-engineering report is unique, prepared solely for the client. Those who rely on a geotechnical-engineering report prepared for a different client can be seriously misled. No one except authorized client representatives should rely on this geotechnical-engineering report without first conferring with the geotechnical engineer who prepared it. And no one – not even you – should apply this report for any purpose or project except the one originally contemplated. Read this Report in FullCostly problems have occurred because those relying on a geotechnical-engineering report did not read it in its entirety. Do not rely on an executive summary. Do not read selected elements only. Read this report in full. You Need to Inform Your Geotechnical Engineer about ChangeYour geotechnical engineer considered unique, project-specific factors when designing the study behind this report and developing the confirmation-dependent recommendations the report conveys. A few typical factors include: • the client’s goals, objectives, budget, schedule, and risk-management preferences; • the general nature of the structure involved, its size, configuration, and performance criteria; • the structure’s location and orientation on the site; and • other planned or existing site improvements, such as retaining walls, access roads, parking lots, and underground utilities. Typical changes that could erode the reliability of this report include those that affect: • the site’s size or shape; • the function of the proposed structure, as when it’s changed from a parking garage to an office building, or from a light-industrial plant to a refrigerated warehouse; • the elevation, configuration, location, orientation, or weight of the proposed structure; • the composition of the design team; or • project ownership. As a general rule, always inform your geotechnical engineer of project changes – even minor ones – and request an assessment of their impact. The geotechnical engineer who prepared this report cannot accept responsibility or liability for problems that arise because the geotechnical engineer was not informed about developments the engineer otherwise would have considered. This Report May Not Be ReliableDo not rely on this report if your geotechnical engineer prepared it: • for a different client; • for a different project; • for a different site (that may or may not include all or a portion of the original site); or • before important events occurred at the site or adjacent to it; e.g., man-made events like construction or environmental remediation, or natural events like floods, droughts, earthquakes, or groundwater fluctuations. Note, too, that it could be unwise to rely on a geotechnical-engineering report whose reliability may have been affected by the passage of time, because of factors like changed subsurface conditions; new or modified codes, standards, or regulations; or new techniques or tools. If your geotechnical engineer has not indicated an “apply-by” date on the report, ask what it should be, and, in general, if you are the least bit uncertain about the continued reliability of this report, contact your geotechnical engineer before applying it. A minor amount of additional testing or analysis – if any is required at all – could prevent major problems. Most of the “Findings” Related in This Report Are Professional Opinions Before construction begins, geotechnical engineers explore a site’s subsurface through various sampling and testing procedures. Geotechnical engineers can observe actual subsurface conditions only at those specific locations where sampling and testing were performed. The data derived from that sampling and testing were reviewed by your geotechnical engineer, who then applied professional judgment to form opinions about subsurface conditions throughout the site. Actual sitewide-subsurface conditions may differ – maybe significantly – from those indicated in this report. Confront that risk by retaining your geotechnical engineer to serve on the design team from project start to project finish, so the individual can provide informed guidance quickly, whenever needed. This Report’s Recommendations Are Confirmation-DependentThe recommendations included in this report – including any options or alternatives – are confirmation-dependent. In other words, they are not final, because the geotechnical engineer who developed them relied heavily on judgment and opinion to do so. Your geotechnical engineer can finalize the recommendations only after observing actual subsurface conditions revealed during construction. If through observation your geotechnical engineer confirms that the conditions assumed to exist actually do exist, the recommendations can be relied upon, assuming no other changes have occurred. The geotechnical engineer who prepared this report cannot assume responsibility or liability for confirmation-dependent recommendations if you fail to retain that engineer to perform construction observation. This Report Could Be MisinterpretedOther design professionals’ misinterpretation of geotechnical-engineering reports has resulted in costly problems. Confront that risk by having your geotechnical engineer serve as a full-time member of the design team, to: • confer with other design-team members, • help develop specifications, • review pertinent elements of other design professionals’ plans and specifications, and • be on hand quickly whenever geotechnical-engineering guidance is needed. You should also confront the risk of constructors misinterpreting this report. Do so by retaining your geotechnical engineer to participate in prebid and preconstruction conferences and to perform construction observation. Give Constructors a Complete Report and GuidanceSome owners and design professionals mistakenly believe they can shift unanticipated-subsurface-conditions liability to constructors by limiting the information they provide for bid preparation. To help prevent the costly, contentious problems this practice has caused, include the complete geotechnical-engineering report, along with any attachments or appendices, with your contract documents, but be certain to note conspicuously that you’ve included the material for informational purposes only. To avoid misunderstanding, you may also want to note that “informational purposes” means constructors have no right to rely on the interpretations, opinions, conclusions, or recommendations in the report, but they may rely on the factual data relative to the specific times, locations, and depths/elevations referenced. Be certain that constructors know they may learn about specific project requirements, including options selected from the report, only from the design drawings and specifications. Remind constructors that they may perform their own studies if they want to, and be sure to allow enough time to permit them to do so. Only then might you be in a position to give constructors the information available to you, while requiring them to at least share some of the financial responsibilities stemming from unanticipated conditions. Conducting prebid and preconstruction conferences can also be valuable in this respect. Read Responsibility Provisions Closely Some client representatives, design professionals, and constructors do not realize that geotechnical engineering is far less exact than other engineering disciplines. That lack of understanding has nurtured unrealistic expectations that have resulted in disappointments, delays, cost overruns, claims, and disputes. To confront that risk, geotechnical engineers commonly include explanatory provisions in their reports. Sometimes labeled “limitations,” many of these provisions indicate where geotechnical engineers’ responsibilities begin and end, to help others recognize their own responsibilities and risks. Read these provisions closely. Ask questions. Your geotechnical engineer should respond fully and frankly. Geoenvironmental Concerns Are Not Covered The personnel, equipment, and techniques used to perform an environmental study – e.g., a “phase-one” or “phase-two” environmental site assessment – differ significantly from those used to perform a geotechnical-engineering study. For that reason, a geotechnical- engineering report does not usually relate any environmental findings, conclusions, or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Unanticipated subsurface environmental problems have led to project failures. If you have not yet obtained your own environmental information, ask your geotechnical consultant for risk-management guidance. As a general rule, do not rely on an environmental report prepared for a different client, site, or project, or that is more than six months old. Obtain Professional Assistance to Deal with Moisture Infiltration and Mold While your geotechnical engineer may have addressed groundwater, water infiltration, or similar issues in this report, none of the engineer’s services were designed, conducted, or intended to prevent uncontrolled migration of moisture – including water vapor – from the soil through building slabs and walls and into the building interior, where it can cause mold growth and material-performance deficiencies. Accordingly, proper implementation of the geotechnical engineer’s recommendations will not of itself be sufficient to prevent moisture infiltration. Confront the risk of moisture infiltration by including building-envelope or mold specialists on the design team. Geotechnical engineers are not building-envelope or mold specialists. Copyright 2016 by Geoprofessional Business Association (GBA). Duplication, reproduction, or copying of this document, in whole or in part, by any means whatsoever, is strictly prohibited, except with GBA’s specific written permission. Excerpting, quoting, or otherwise extracting wording from this document is permitted only with the express written permission of GBA, and only for purposes of scholarly research or book review. Only members of GBA may use this document or its wording as a complement to or as an element of a report of any kind. Any other firm, individual, or other entity that so uses this document without being a GBA member could be committing negligent Telephone: 301/565-2733 e-mail: info@geoprofessional.org www.geoprofessional.org