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HomeMy WebLinkAbout5365 Stormwater Memorandum 12-8-20231 | Page Drainage Memorandum To: City of Springfield From: Destin Takenaka-Amodo, EIT Reviewed by: Scott Morris, PE Date: 12/8/2023 Taxmap & TL: 18-02-06-11-00400 Re: Drainage Report for Spiker – North Street Partition Project Overview This storm analysis is for a proposed three-lot partition located at 4096 North Street in Springfield, Oregon. The applicant is proposing to partition the above property into three new parcels. Parcel 3 has an existing single home structure that is to be demolished and transitioned into one of the duplex structures proposed. The new driveway locations for Parcel 1 are on Redwood Dr, Parcel 2 is on Filbert Ln, and Parcel 3 is on North St. Parcels 1 & 3 are proposed new residential duplex dwellings and are to be served by their own driveways. Parcel 2 will serve as a single-family floor plan. All parcels are proposed to treat and infiltrate stormwater runoff with three separate infiltration rain gardens with pipe storage located on each property. Infiltration An infiltration test is to be completed during the building permit process to verify actual infiltration rate and water table elevation. Web Soil Survey classifies the soils on-site as Chapman-Urban Land Complex (#25) with a hydrologic soil group B. Web Soil Survey also describes in the infiltration rate as being 0.57 to 1.98 inches per hour, as well as the water table elevation being greater than 80” below the grounds surface. 380 Q Street, Ste 200 Springfield, Oregon 97477 (541) 302-9790 destinta@ao-engr.com 2 | Page Stormwater Calculation Parameters To perform the stormwater calculations City of Springfield standards were followed. HydroCAD software was utilized to perform hydraulic and hydrology calculations. Below are the parameters that were used for the stormwater calculations with their respective sources in (parenthesis). All parameters were taken from the City of Springfield Engineering Design Standards & Procedures Manual unless otherwise noted: Water Quality Precipitation: 0.83” in 24 hours On-Site Design Storm: 2-Year design storm 2-Year Precipitation: 3.30” in 24 hours 25-Year Precipitation: 4.80” in 24 hours Storm Distribution Type: IA – 24-hour (NRCS SCS Rainfall Distributions) Manning’s n Number: 0.011 Runoff Method: Santa Barbara Urban Hydrograph Method (SBUH) Time of Concentration: Minimum 10 minutes Proposed Stormwater System It is proposed to construct infiltration rain gardens to process, treat and convey stormwater runoff from each of the future home roofs. Since site soils were shown to have good infiltration characteristics, no overflows are proposed. Each facility’s depth is 12 inches, with a side slope maximum of 3:1. The minimum bottom width is 2 feet. The infiltration rain gardens are placed 10 ft from building foundations and 5 ft from property lines. Hydraulic Calculations The total driveway square-footage for each parcel is expected to be around 467.90 – 497.00sq-ft. Per City of Springfield Code 3.02.5, the driveways for each parcel are excluded from storm drainage design due to the square footage being less than 500 sq-ft. 65% of the parcel area per parcel is considered impervious for preliminary design. Final sizes for stormwater facilities will be determined during the building permit process. The infiltration rain gardens were designed with the following variables: Table 2: Impervious Area Dimensions and Curve Numbers. Parcel Number Drainage Area Impervious Area (sf) CN 1 Duplex Roof 3,200 98 2 Duplex Roof 1,600 98 3 Duplex Roof 3,200 98 3 | Page The existing conditions were designed with the following variables: Table 3: Existing Conditions. Description Area (sf) CN HydroCAD Node >75% Grass Cover, Good, HSG B 12,952 61 EC Existing Roofs and Pavement 2,965 98 EC Hydraulic calculations were performed to ensure the stormwater facilities are sized accordingly to be contained within the stormwater facilities. HydroCAD software was utilized to perform the hydrologic calculations and the HGL determinations. Shown below is a summary of the proposed infiltration rain gardens with pipe storage physical characteristics: Table 4: Infiltration Rain Garden Physical Characteristics. Facility Open Storage Depth (ft) Growing Medium Depth (ft) Rock Chamber Depth (ft) Side Slopes Depth (ft) Infiltration Rain Garden #1 1 1 5 3:1 6 Infiltration Rain Garden #2 1 1 5 3:1 6 Infiltration Rain Garden #3 1 1 5 3:1 6 Table 5: Pipe Storage Physical Characteristics. Facility Invert Elevation (ft) Length (Ft) Diameter (inches) Infiltration Rain Garden #1 477.50 13 36 Infiltration Rain Garden #2 477.50 9 12 Infiltration Rain Garden #3 477.50 13 36 The HGLs of the infiltration rain gardens were checked to ensure no damage would occur on any of the structures. Below is a table summary of each of the trenches: Table 5: Stormwater Facility Elevations and Hydraulic Grade Lines. Facility FL Elevation (ft) Flood Elevation (ft) 2-Year HGL (ft) 25-Year HGL (ft) Infiltration Rain Garden #1 482.50 483.50 483.21 483.64 Infiltration Rain Garden #2 482.50 483.50 483.22 483.55 Infiltration Rain Garden #3 482.50 483.50 483.21 484.64 4 | Page As shown in the table above, HGL ranges from 0.05 – 0.14 ft above the flood elevation of the stormwater facility flood elevations which is not significant to cause damage to surrounding infrastructure. Another component is detaining peak flowrates. Since the proposal is to infiltrate all stormwater runoff from the new impervious areas, detention requirements are met. Conclusion The proposed stormwater system will serve the development adequately. Water quality will be provided by the vegetative contact time by allowing for infiltration during the water quality storm event. The proposed system will not cause any damage to the proposed development or surrounding infrastructure. Appendix • HydroCAD calculations for Spiker – North Street Partition • Storm Scoping Sheet 1S Parcel 1 2S Parcel 2 3S Parcel 3 4S Parcel 1 5S Parcel 2 6S Parcel 3 7S Parcel 1 8S Parcel 2 9S Parcel 3 EC Existing Conditions 1R Post Construction Peak Flowrate 24R POST 1P1 Foundation Planter (1) 1P2 Rock Chamber (1) 1P3 Rock Chamber w Pipe (1) 2P1 Foundation Planter (2) 2P2 Rock Chamber (2) 2P3 Rock Chamber w Pipe (2) 3P1 Foundation Planter (3) 3P2 Rock Chamber (3) 3P3 Rock Chamber w Pipe (3) 4P Soakage Trench (1) 5P Soakage Trench (2) 6P Soakage Trench (3) 10P Infiltration Rain Garden #1 16P Infiltration Rain Garden #2 22P Infiltration Rain Garden #3 Routing Diagram for 5365 Spiker Storm BAW-sdm-10-24-2023Prepared by A&O Engineering LLC, Printed 1/3/2024 HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Subcat Reach Pond Link Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 2HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: Parcel 1 At time of modeling, future impervious area is unknown. 46% of the lot assumed to be impervious based on expected residence sizes. Model can be refined once home footprints are known. [49] Hint: Tc<2dt may require smaller dt Runoff = 0.04 cfs @ 7.90 hrs, Volume= 0.015 af, Depth= 3.07" Routed to Pond 1P3 : Rock Chamber w Pipe (1) Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type IA 24-hr 2-Year Rainfall=3.30" Area (sf) CN Description 2,500 98 Unconnected roofs, HSG B 2,500 98 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 1S: Parcel 1 Runoff Hydrograph Time (hours)484644424038363432302826242220181614121086420Flow (cfs)0.048 0.046 0.044 0.042 0.04 0.038 0.036 0.034 0.032 0.03 0.028 0.026 0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 Type IA 24-hr 2-Year Rainfall=3.30" Runoff Area=2,500 sf Runoff Volume=0.015 af Runoff Depth=3.07" Tc=5.0 min CN=0/98 0.04 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 3HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: Parcel 2 At time of modeling, future impervious area is unknown. 49% of the lot assumed to be impervious based on expected residence sizes. Model can be refined once home footprints are known. [49] Hint: Tc<2dt may require smaller dt Runoff = 0.05 cfs @ 7.94 hrs, Volume= 0.017 af, Depth= 1.79" Routed to Pond 2P3 : Rock Chamber w Pipe (2) Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type IA 24-hr 2-Year Rainfall=3.30" Area (sf) CN Description * 5,101 80 49% imp, HSG B 2,602 63 51.00% Pervious Area 2,499 98 49.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 2S: Parcel 2 Runoff Hydrograph Time (hours)484644424038363432302826242220181614121086420Flow (cfs)0.05 0.048 0.046 0.044 0.042 0.04 0.038 0.036 0.034 0.032 0.03 0.028 0.026 0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 Type IA 24-hr 2-Year Rainfall=3.30" Runoff Area=5,101 sf Runoff Volume=0.017 af Runoff Depth=1.79" Tc=5.0 min CN=63/98 0.05 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 4HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment 3S: Parcel 3 At time of modeling, future impervious area is unknown. 46% of the lot assumed to be impervious based on expected residence sizes. Model can be refined once home footprints are known. [49] Hint: Tc<2dt may require smaller dt Runoff = 0.04 cfs @ 7.93 hrs, Volume= 0.017 af, Depth= 1.67" Routed to Pond 3P3 : Rock Chamber w Pipe (3) Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type IA 24-hr 2-Year Rainfall=3.30" Area (sf) CN Description * 5,413 78 46% imp, HSG B 2,923 61 54.00% Pervious Area 2,490 98 46.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 3S: Parcel 3 Runoff Hydrograph Time (hours)484644424038363432302826242220181614121086420Flow (cfs)0.048 0.046 0.044 0.042 0.04 0.038 0.036 0.034 0.032 0.03 0.028 0.026 0.024 0.0220.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 Type IA 24-hr 2-Year Rainfall=3.30" Runoff Area=5,413 sf Runoff Volume=0.017 af Runoff Depth=1.67" Tc=5.0 min CN=61/98 0.04 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 5HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment 4S: Parcel 1 At time of modeling, future impervious area is unknown. 46% of the lot assumed to be impervious based on expected residence sizes. Model can be refined once home footprints are known. [49] Hint: Tc<2dt may require smaller dt Runoff = 0.06 cfs @ 7.90 hrs, Volume= 0.019 af, Depth= 3.07" Routed to Pond 4P : Soakage Trench (1) Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type IA 24-hr 2-Year Rainfall=3.30" Area (sf) CN Description 3,200 98 Unconnected roofs, HSG B 3,200 98 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 4S: Parcel 1 Runoff Hydrograph Time (hours)484644424038363432302826242220181614121086420Flow (cfs)0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Type IA 24-hr 2-Year Rainfall=3.30" Runoff Area=3,200 sf Runoff Volume=0.019 af Runoff Depth=3.07" Tc=5.0 min CN=0/98 0.06 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 6HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment 5S: Parcel 2 At time of modeling, future impervious area is unknown. 49% of the lot assumed to be impervious based on expected residence sizes. Model can be refined once home footprints are known. [49] Hint: Tc<2dt may require smaller dt Runoff = 0.03 cfs @ 7.90 hrs, Volume= 0.009 af, Depth= 3.07" Routed to Pond 5P : Soakage Trench (2) Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type IA 24-hr 2-Year Rainfall=3.30" Area (sf) CN Description 1,600 98 Unconnected roofs, HSG B 1,600 98 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 5S: Parcel 2 Runoff Hydrograph Time (hours)484644424038363432302826242220181614121086420Flow (cfs)0.03 0.028 0.026 0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 Type IA 24-hr 2-Year Rainfall=3.30" Runoff Area=1,600 sf Runoff Volume=0.009 af Runoff Depth=3.07" Tc=5.0 min CN=0/98 0.03 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 7HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment 6S: Parcel 3 At time of modeling, future impervious area is unknown. 46% of the lot assumed to be impervious based on expected residence sizes. Model can be refined once home footprints are known. [49] Hint: Tc<2dt may require smaller dt Runoff = 0.06 cfs @ 7.90 hrs, Volume= 0.019 af, Depth= 3.07" Routed to Pond 6P : Soakage Trench (3) Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type IA 24-hr 2-Year Rainfall=3.30" Area (sf) CN Description 3,200 98 Unconnected roofs, HSG B 3,200 98 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 6S: Parcel 3 Runoff Hydrograph Time (hours)484644424038363432302826242220181614121086420Flow (cfs)0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Type IA 24-hr 2-Year Rainfall=3.30" Runoff Area=3,200 sf Runoff Volume=0.019 af Runoff Depth=3.07" Tc=5.0 min CN=0/98 0.06 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 8HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment 7S: Parcel 1 At time of modeling, future impervious area is unknown. 46% of the lot assumed to be impervious based on expected residence sizes. Model can be refined once home footprints are known. [49] Hint: Tc<2dt may require smaller dt Runoff = 0.06 cfs @ 7.90 hrs, Volume= 0.019 af, Depth= 3.07" Routed to Pond 10P : Infiltration Rain Garden #1 Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type IA 24-hr 2-Year Rainfall=3.30" Area (sf) CN Description 3,200 98 Unconnected roofs, HSG B 3,200 98 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 7S: Parcel 1 Runoff Hydrograph Time (hours)484644424038363432302826242220181614121086420Flow (cfs)0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Type IA 24-hr 2-Year Rainfall=3.30" Runoff Area=3,200 sf Runoff Volume=0.019 af Runoff Depth=3.07" Tc=5.0 min CN=0/98 0.06 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 9HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment 8S: Parcel 2 At time of modeling, future impervious area is unknown. 49% of the lot assumed to be impervious based on expected residence sizes. Model can be refined once home footprints are known. [49] Hint: Tc<2dt may require smaller dt Runoff = 0.03 cfs @ 7.90 hrs, Volume= 0.009 af, Depth= 3.07" Routed to Pond 16P : Infiltration Rain Garden #2 Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type IA 24-hr 2-Year Rainfall=3.30" Area (sf) CN Description 1,600 98 Unconnected roofs, HSG B 1,600 98 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 8S: Parcel 2 Runoff Hydrograph Time (hours)484644424038363432302826242220181614121086420Flow (cfs)0.03 0.028 0.026 0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 Type IA 24-hr 2-Year Rainfall=3.30" Runoff Area=1,600 sf Runoff Volume=0.009 af Runoff Depth=3.07" Tc=5.0 min CN=0/98 0.03 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 10HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment 9S: Parcel 3 At time of modeling, future impervious area is unknown. 46% of the lot assumed to be impervious based on expected residence sizes. Model can be refined once home footprints are known. [49] Hint: Tc<2dt may require smaller dt Runoff = 0.06 cfs @ 7.90 hrs, Volume= 0.019 af, Depth= 3.07" Routed to Pond 22P : Infiltration Rain Garden #3 Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type IA 24-hr 2-Year Rainfall=3.30" Area (sf) CN Description 3,200 98 Unconnected roofs, HSG B 3,200 98 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 9S: Parcel 3 Runoff Hydrograph Time (hours)484644424038363432302826242220181614121086420Flow (cfs)0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Type IA 24-hr 2-Year Rainfall=3.30" Runoff Area=3,200 sf Runoff Volume=0.019 af Runoff Depth=3.07" Tc=5.0 min CN=0/98 0.06 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 11HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment EC: Existing Conditions Impervious area included existing home roof, existing garage roof and existing on-site pavement. Runoff = 0.05 cfs @ 8.00 hrs, Volume= 0.029 af, Depth= 0.97" Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type IA 24-hr 2-Year Rainfall=3.30" Area (sf) CN Description 12,952 61 >75% Grass cover, Good, HSG B * 2,965 98 Existing Roofs and Pavement 15,917 68 Weighted Average 12,952 61 81.37% Pervious Area 2,965 98 18.63% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment EC: Existing Conditions Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Type IA 24-hr 2-Year Rainfall=3.30" Runoff Area=15,917 sf Runoff Volume=0.029 af Runoff Depth=0.97" Tc=10.0 min CN=61/98 0.05 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 12HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Reach 1R: Post Construction Peak Flowrate [40] Hint: Not Described (Outflow=Inflow) Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Outflow = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Reach 1R: Post Construction Peak Flowrate InflowOutflow Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 0.00 cfs0.00 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 13HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Reach 24R: POST [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 0.184 ac,100.00% Impervious, Inflow Depth = 0.00" for 2-Year event Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Outflow = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Reach 24R: POST InflowOutflow Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Inflow Area=0.184 ac 0.00 cfs0.00 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 14HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Pond 1P1: Foundation Planter (1) [43] Hint: Has no inflow (Outflow=Zero) Volume Invert Avail.Storage Storage Description #1 483.21' 0.003 af 4.00'W x 29.00'L x 1.00'H Open Basin #2 482.21' 0.000 af 4.00'W x 29.00'L x 1.00'H Growing Medium 0.003 af Overall x 10.0% Voids #3 481.21' 0.001 af 4.00'W x 29.00'L x 1.00'H Rock Chamber 0.003 af Overall x 35.0% Voids 0.004 af Total Available Storage Device Routing Invert Outlet Devices #1 Primary 481.21'4.0" Round 4" Outflow Pipe L= 10.0' CPP, mitered to conform to fill, Ke= 0.700 Inlet / Outlet Invert= 481.21' / 481.21' S= 0.0000 '/' Cc= 0.900 n= 0.011, Flow Area= 0.09 sf #2 Device 1 481.21'2.000 in/hr Infiltration into Soil over Horizontal area #3 Device 1 484.00'4.0" Horiz. 4" Overflow C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=0.00' TW=0.00' (Dynamic Tailwater) 1=4" Outflow Pipe ( Controls 0.00 cfs) 2=Infiltration into Soil ( Controls 0.00 cfs) 3=4" Overflow ( Controls 0.00 cfs) Pond 1P1: Foundation Planter (1) Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Peak Elev=0.00' Storage=0.000 af 0.00 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 15HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Pond 1P2: Rock Chamber (1) [43] Hint: Has no inflow (Outflow=Zero) Volume Invert Avail.Storage Storage Description #1 479.21' 0.004 af 5.00'W x 20.00'L x 5.00'H Rock Chamber 0.011 af Overall x 35.0% Voids Device Routing Invert Outlet Devices #1 Discarded 479.21'2.000 in/hr Infiltration into Soil over Wetted area Discarded OutFlow Max=0.00 cfs @ 0.00 hrs HW=0.00' (Free Discharge) 1=Infiltration into Soil ( Controls 0.00 cfs) Pond 1P2: Rock Chamber (1) Discarded Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Peak Elev=0.00' Storage=0.000 af 0.00 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 16HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Pond 1P3: Rock Chamber w Pipe (1) Inflow Area = 0.057 ac,100.00% Impervious, Inflow Depth = 3.07" for 2-Year event Inflow = 0.04 cfs @ 7.90 hrs, Volume= 0.015 af Outflow = 0.01 cfs @ 9.78 hrs, Volume= 0.015 af, Atten= 77%, Lag= 113.0 min Discarded = 0.01 cfs @ 9.78 hrs, Volume= 0.015 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 482.93' @ 9.78 hrs Surf.Area= 0.002 ac Storage= 0.004 af Flood Elev= 484.21' Surf.Area= 0.002 ac Storage= 0.004 af Plug-Flow detention time= 177.3 min calculated for 0.015 af (100% of inflow) Center-of-Mass det. time= 177.4 min ( 842.9 - 665.6 ) Volume Invert Avail.Storage Storage Description #1 479.21' 0.002 af 5.00'W x 15.00'L x 5.00'H Rock Chamber 0.009 af Overall - 0.002 af Embedded = 0.006 af x 35.0% Voids #2 480.21' 0.002 af 36.0" Round Pipe Storage - 36" Inside #1 L= 14.0' 0.004 af Total Available Storage Device Routing Invert Outlet Devices #1 Discarded 479.21'2.000 in/hr Infiltration into Soil over Wetted area Discarded OutFlow Max=0.01 cfs @ 9.78 hrs HW=482.93' (Free Discharge) 1=Infiltration into Soil (Exfiltration Controls 0.01 cfs) Pond 1P3: Rock Chamber w Pipe (1) InflowDiscarded Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.048 0.046 0.044 0.042 0.04 0.038 0.036 0.034 0.032 0.03 0.028 0.026 0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 Inflow Area=0.057 ac Peak Elev=482.93' Storage=0.004 af 0.04 cfs 0.01 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 17HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Pond 2P1: Foundation Planter (2) [43] Hint: Has no inflow (Outflow=Zero) Volume Invert Avail.Storage Storage Description #1 483.09' 0.003 af 4.00'W x 29.00'L x 1.00'H Open Basin #2 482.09' 0.000 af 4.00'W x 29.00'L x 1.00'H Growing Medium 0.003 af Overall x 10.0% Voids #3 481.09' 0.001 af 4.00'W x 29.00'L x 1.00'H Rock Chamber 0.003 af Overall x 35.0% Voids 0.004 af Total Available Storage Device Routing Invert Outlet Devices #1 Primary 481.09'4.0" Round 4" Outflow Pipe L= 10.0' CPP, mitered to conform to fill, Ke= 0.700 Inlet / Outlet Invert= 481.09' / 481.09' S= 0.0000 '/' Cc= 0.900 n= 0.011, Flow Area= 0.09 sf #2 Discarded 481.09'2.000 in/hr Infiltration into Soil over Horizontal area #3 Device 1 483.89'4.0" Horiz. 4" Overflow C= 0.600 Limited to weir flow at low heads Discarded OutFlow Max=0.00 cfs @ 0.00 hrs HW=0.00' (Free Discharge) 2=Infiltration into Soil ( Controls 0.00 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=0.00' TW=0.00' (Dynamic Tailwater) 1=4" Outflow Pipe ( Controls 0.00 cfs) 3=4" Overflow ( Controls 0.00 cfs) Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 18HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Pond 2P1: Foundation Planter (2) Discarded Primary Hydrograph Time (hours)484644424038363432302826242220181614121086420Flow (cfs)1 0 Peak Elev=0.00' Storage=0.000 af 0.00 cfs0.00 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 19HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Pond 2P2: Rock Chamber (2) [43] Hint: Has no inflow (Outflow=Zero) Volume Invert Avail.Storage Storage Description #1 474.09' 0.006 af 5.00'W x 15.00'L x 10.00'H Rock Chamber 0.017 af Overall x 35.0% Voids Device Routing Invert Outlet Devices #1 Discarded 474.09'2.000 in/hr Infiltration into Soil over Wetted area Discarded OutFlow Max=0.00 cfs @ 0.00 hrs HW=0.00' (Free Discharge) 1=Infiltration into Soil ( Controls 0.00 cfs) Pond 2P2: Rock Chamber (2) Discarded Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Peak Elev=0.00' Storage=0.000 af 0.00 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 20HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Pond 2P3: Rock Chamber w Pipe (2) Inflow Area = 0.117 ac, 49.00% Impervious, Inflow Depth = 1.79" for 2-Year event Inflow = 0.05 cfs @ 7.94 hrs, Volume= 0.017 af Outflow = 0.01 cfs @ 9.98 hrs, Volume= 0.017 af, Atten= 74%, Lag= 122.5 min Discarded = 0.01 cfs @ 9.98 hrs, Volume= 0.017 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 481.29' @ 9.98 hrs Surf.Area= 0.003 ac Storage= 0.003 af Flood Elev= 484.09' Surf.Area= 0.003 ac Storage= 0.007 af Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 107.4 min ( 818.5 - 711.1 ) Volume Invert Avail.Storage Storage Description #1 479.09' 0.006 af 15.00'W x 10.00'L x 5.00'H Rock Chamber 0.017 af Overall - 0.001 af Embedded = 0.016 af x 35.0% Voids #2 480.09' 0.001 af 36.0" Round Pipe Storage - 36" Inside #1 L= 8.0' 0.007 af Total Available Storage Device Routing Invert Outlet Devices #1 Discarded 479.09'2.000 in/hr Infiltration into Soil over Wetted area Discarded OutFlow Max=0.01 cfs @ 9.98 hrs HW=481.29' (Free Discharge) 1=Infiltration into Soil (Exfiltration Controls 0.01 cfs) Pond 2P3: Rock Chamber w Pipe (2) InflowDiscarded Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Inflow Area=0.117 ac Peak Elev=481.29' Storage=0.003 af 0.05 cfs 0.01 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 21HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Pond 3P1: Foundation Planter (3) [43] Hint: Has no inflow (Outflow=Zero) Volume Invert Avail.Storage Storage Description #1 482.97' 0.003 af 4.00'W x 29.00'L x 1.00'H Open Basin #2 481.97' 0.000 af 4.00'W x 29.00'L x 1.00'H Growing Medium 0.003 af Overall x 10.0% Voids #3 480.97' 0.001 af 4.00'W x 29.00'L x 1.00'H Rock Chamber 0.003 af Overall x 35.0% Voids 0.004 af Total Available Storage Device Routing Invert Outlet Devices #1 Primary 480.97'4.0" Round 4" Outflow Pipe L= 10.0' CPP, mitered to conform to fill, Ke= 0.700 Inlet / Outlet Invert= 480.97' / 480.97' S= 0.0000 '/' Cc= 0.900 n= 0.011, Flow Area= 0.09 sf #2 Discarded 480.97'2.000 in/hr Infiltration into Soil over Horizontal area #3 Device 1 483.77'4.0" Horiz. 4" Overflow C= 0.600 Limited to weir flow at low heads Discarded OutFlow Max=0.00 cfs @ 0.00 hrs HW=0.00' (Free Discharge) 2=Infiltration into Soil ( Controls 0.00 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=0.00' TW=0.00' (Dynamic Tailwater) 1=4" Outflow Pipe ( Controls 0.00 cfs) 3=4" Overflow ( Controls 0.00 cfs) Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 22HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Pond 3P1: Foundation Planter (3) Discarded Primary Hydrograph Time (hours)484644424038363432302826242220181614121086420Flow (cfs)1 0 Peak Elev=0.00' Storage=0.000 af 0.00 cfs0.00 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 23HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Pond 3P2: Rock Chamber (3) [43] Hint: Has no inflow (Outflow=Zero) Volume Invert Avail.Storage Storage Description #1 473.97' 0.006 af 5.00'W x 15.00'L x 10.00'H Rock Chamber 0.017 af Overall x 35.0% Voids Device Routing Invert Outlet Devices #1 Discarded 473.97'2.000 in/hr Exfiltration over Wetted area Discarded OutFlow Max=0.00 cfs @ 0.00 hrs HW=0.00' (Free Discharge) 1=Exfiltration ( Controls 0.00 cfs) Pond 3P2: Rock Chamber (3) Discarded Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Peak Elev=0.00' Storage=0.000 af 0.00 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 24HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Pond 3P3: Rock Chamber w Pipe (3) Inflow Area = 0.124 ac, 46.00% Impervious, Inflow Depth = 1.67" for 2-Year event Inflow = 0.04 cfs @ 7.93 hrs, Volume= 0.017 af Outflow = 0.01 cfs @ 9.94 hrs, Volume= 0.017 af, Atten= 73%, Lag= 121.2 min Discarded = 0.01 cfs @ 9.94 hrs, Volume= 0.017 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 481.11' @ 9.94 hrs Surf.Area= 0.003 ac Storage= 0.003 af Plug-Flow detention time= 104.8 min calculated for 0.017 af (100% of inflow) Center-of-Mass det. time= 105.2 min ( 818.2 - 713.1 ) Volume Invert Avail.Storage Storage Description #1 478.97' 0.006 af 15.00'W x 10.00'L x 5.00'H Rock Chamber 0.017 af Overall - 0.001 af Embedded = 0.016 af x 35.0% Voids #2 479.97' 0.001 af 36.0" Round Pipe Storage - 36" Inside #1 L= 8.0' 0.007 af Total Available Storage Device Routing Invert Outlet Devices #1 Discarded 478.97'2.000 in/hr Infiltration into Soil over Wetted area Discarded OutFlow Max=0.01 cfs @ 9.94 hrs HW=481.11' (Free Discharge) 1=Infiltration into Soil (Exfiltration Controls 0.01 cfs) Pond 3P3: Rock Chamber w Pipe (3) InflowDiscarded Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.048 0.046 0.044 0.042 0.04 0.038 0.036 0.034 0.032 0.03 0.028 0.026 0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 Inflow Area=0.124 ac Peak Elev=481.11' Storage=0.003 af 0.04 cfs 0.01 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 25HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Pond 4P: Soakage Trench (1) Inflow Area = 0.073 ac,100.00% Impervious, Inflow Depth = 3.07" for 2-Year event Inflow = 0.06 cfs @ 7.90 hrs, Volume= 0.019 af Outflow = 0.01 cfs @ 3.90 hrs, Volume= 0.019 af, Atten= 90%, Lag= 0.0 min Primary = 0.01 cfs @ 3.90 hrs, Volume= 0.019 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 482.21' @ 21.12 hrs Surf.Area= 124 sf Storage= 362 cf Flood Elev= 483.50' Surf.Area= 124 sf Storage= 375 cf Plug-Flow detention time= 625.5 min calculated for 0.019 af (100% of inflow) Center-of-Mass det. time= 626.2 min ( 1,291.7 - 665.6 ) Volume Invert Avail.Storage Storage Description #1 476.50' 199 cf 7.75'W x 16.00'L x 6.00'H Rock Chamber 744 cf Overall - 176 cf Embedded = 568 cf x 35.0% Voids #2 477.50' 176 cf 48.0" Round Pipe Storage - 48" Inside #1 L= 14.0' 375 cf Total Available Storage Device Routing Invert Outlet Devices #1 Primary 476.50'1.980 in/hr Infiltration into Soil over Surface area Primary OutFlow Max=0.01 cfs @ 3.90 hrs HW=476.57' (Free Discharge) 1=Infiltration into Soil (Exfiltration Controls 0.01 cfs) Pond 4P: Soakage Trench (1) InflowPrimary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Inflow Area=0.073 ac Peak Elev=482.21' Storage=362 cf 0.06 cfs 0.01 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 26HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Pond 5P: Soakage Trench (2) Inflow Area = 0.037 ac,100.00% Impervious, Inflow Depth = 3.07" for 2-Year event Inflow = 0.03 cfs @ 7.90 hrs, Volume= 0.009 af Outflow = 0.00 cfs @ 4.50 hrs, Volume= 0.009 af, Atten= 88%, Lag= 0.0 min Discarded = 0.00 cfs @ 4.50 hrs, Volume= 0.009 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 482.03' @ 17.89 hrs Surf.Area= 0.002 ac Storage= 0.003 af Flood Elev= 483.50' Surf.Area= 0.002 ac Storage= 0.004 af Plug-Flow detention time= 435.5 min calculated for 0.009 af (100% of inflow) Center-of-Mass det. time= 436.0 min ( 1,101.6 - 665.6 ) Volume Invert Avail.Storage Storage Description #1 478.50' 0.002 af 5.00'W x 15.00'L x 5.00'H Rock Chamber 0.009 af Overall - 0.002 af Embedded = 0.006 af x 35.0% Voids #2 479.50' 0.002 af 36.0" Round Pipe Storage - 36" Inside #1 L= 13.0' 0.004 af Total Available Storage Device Routing Invert Outlet Devices #1 Discarded 478.50'1.980 in/hr Infiltration into Soil over Surface area Discarded OutFlow Max=0.00 cfs @ 4.50 hrs HW=478.55' (Free Discharge) 1=Infiltration into Soil (Exfiltration Controls 0.00 cfs) Pond 5P: Soakage Trench (2) InflowDiscarded Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.03 0.028 0.026 0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 Inflow Area=0.037 ac Peak Elev=482.03' Storage=0.003 af 0.03 cfs 0.00 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 27HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Pond 6P: Soakage Trench (3) Inflow Area = 0.073 ac,100.00% Impervious, Inflow Depth = 3.07" for 2-Year event Inflow = 0.06 cfs @ 7.90 hrs, Volume= 0.019 af Outflow = 0.01 cfs @ 3.90 hrs, Volume= 0.019 af, Atten= 90%, Lag= 0.0 min Discarded = 0.01 cfs @ 3.90 hrs, Volume= 0.019 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 482.21' @ 21.12 hrs Surf.Area= 0.003 ac Storage= 0.008 af Flood Elev= 483.50' Surf.Area= 0.003 ac Storage= 0.009 af Plug-Flow detention time= 625.5 min calculated for 0.019 af (100% of inflow) Center-of-Mass det. time= 626.2 min ( 1,291.7 - 665.6 ) Volume Invert Avail.Storage Storage Description #1 476.50' 0.005 af 7.75'W x 16.00'L x 6.00'H Rock Chamber 0.017 af Overall - 0.004 af Embedded = 0.013 af x 35.0% Voids #2 477.50' 0.004 af 48.0" Round Pipe Storage - 48" Inside #1 L= 14.0' 0.009 af Total Available Storage Device Routing Invert Outlet Devices #1 Discarded 476.50'1.980 in/hr Infiltration into Soil over Surface area Discarded OutFlow Max=0.01 cfs @ 3.90 hrs HW=476.57' (Free Discharge) 1=Infiltration into Soil (Exfiltration Controls 0.01 cfs) Pond 6P: Soakage Trench (3) InflowDiscarded Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Inflow Area=0.073 ac Peak Elev=482.21' Storage=0.008 af 0.06 cfs 0.01 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 28HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Pond 10P: Infiltration Rain Garden #1 [87] Warning: Oscillations may require smaller dt or Finer Routing (severity=22) Inflow Area = 0.073 ac,100.00% Impervious, Inflow Depth = 3.07" for 2-Year event Inflow = 0.06 cfs @ 7.90 hrs, Volume= 0.019 af Outflow = 0.01 cfs @ 9.47 hrs, Volume= 0.019 af, Atten= 76%, Lag= 94.6 min Discarded = 0.01 cfs @ 9.47 hrs, Volume= 0.019 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routed to Reach 24R : POST Routing by Dyn-Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 483.21' @ 9.47 hrs Surf.Area= 301 sf Storage= 266 cf Flood Elev= 483.50' Surf.Area= 342 sf Storage= 321 cf Plug-Flow detention time= 378.4 min calculated for 0.019 af (100% of inflow) Center-of-Mass det. time= 379.2 min ( 1,044.8 - 665.6 ) Volume Invert Avail.Storage Storage Description #1 482.50' 138 cf Open Storage (Prismatic) Listed below (Recalc) #2 481.50' 7 cf Growing Medium (Prismatic) Listed below (Recalc) 67 cf Overall x 10.0% Voids #3 476.50' 85 cf Rock Chamber (Prismatic) Listed below (Recalc) 335 cf Overall - 92 cf Embedded = 243 cf x 35.0% Voids #4 477.50' 92 cf 36.0" Round Pipe Storage - 36" Inside #3 L= 13.0' 321 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 482.50 67 0 0 483.50 208 138 138 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 481.50 67 0 0 482.50 67 67 67 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 476.50 67 0 0 481.50 67 335 335 Device Routing Invert Outlet Devices #1 Discarded 476.50'1.980 in/hr Infiltration through native soil over Surface area #2 Primary 483.49'3.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 29HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Discarded OutFlow Max=0.01 cfs @ 9.47 hrs HW=483.21' (Free Discharge) 1=Infiltration through native soil (Exfiltration Controls 0.01 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=476.50' TW=0.00' (Dynamic Tailwater) 2=Orifice/Grate ( Controls 0.00 cfs) Pond 10P: Infiltration Rain Garden #1 Inflow Outflow Discarded Primary Hydrograph Time (hours)484644424038363432302826242220181614121086420Flow (cfs)0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Inflow Area=0.073 ac Peak Elev=483.21' Storage=266 cf 0.06 cfs 0.01 cfs0.01 cfs 0.00 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 30HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Pond 16P: Infiltration Rain Garden #2 [87] Warning: Oscillations may require smaller dt or Finer Routing (severity=24) Inflow Area = 0.037 ac,100.00% Impervious, Inflow Depth = 3.07" for 2-Year event Inflow = 0.03 cfs @ 7.90 hrs, Volume= 0.009 af Outflow = 0.01 cfs @ 9.17 hrs, Volume= 0.009 af, Atten= 72%, Lag= 76.4 min Discarded = 0.01 cfs @ 9.17 hrs, Volume= 0.009 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routed to Reach 24R : POST Routing by Dyn-Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 483.22' @ 9.17 hrs Surf.Area= 173 sf Storage= 126 cf Flood Elev= 483.50' Surf.Area= 203 sf Storage= 160 cf Plug-Flow detention time= 311.0 min calculated for 0.009 af (100% of inflow) Center-of-Mass det. time= 311.7 min ( 977.3 - 665.6 ) Volume Invert Avail.Storage Storage Description #1 482.50' 86 cf Open Storage (Prismatic) Listed below (Recalc) #2 481.50' 3 cf Growing Medium (Prismatic) Listed below (Recalc) 32 cf Overall x 10.0% Voids #3 475.50' 65 cf Rock Chamber (Prismatic) Listed below (Recalc) 192 cf Overall - 7 cf Embedded = 185 cf x 35.0% Voids #4 476.50' 7 cf 12.0" Round Pipe Storage - 12" Inside #3 L= 9.0' 160 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 482.50 32 0 0 483.50 139 86 86 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 481.50 32 0 0 482.50 32 32 32 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 475.50 32 0 0 481.50 32 192 192 Device Routing Invert Outlet Devices #1 Discarded 475.50'1.980 in/hr Infiltration through native soil over Surface area #2 Primary 483.49'3.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 31HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Discarded OutFlow Max=0.01 cfs @ 9.17 hrs HW=483.22' (Free Discharge) 1=Infiltration through native soil (Exfiltration Controls 0.01 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=475.50' TW=0.00' (Dynamic Tailwater) 2=Orifice/Grate ( Controls 0.00 cfs) Pond 16P: Infiltration Rain Garden #2 Inflow Outflow Discarded Primary Hydrograph Time (hours)484644424038363432302826242220181614121086420Flow (cfs)0.03 0.028 0.026 0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 Inflow Area=0.037 ac Peak Elev=483.22' Storage=126 cf 0.03 cfs 0.01 cfs0.01 cfs 0.00 cfs Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 32HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Summary for Pond 22P: Infiltration Rain Garden #3 [87] Warning: Oscillations may require smaller dt or Finer Routing (severity=22) Inflow Area = 0.073 ac,100.00% Impervious, Inflow Depth = 3.07" for 2-Year event Inflow = 0.06 cfs @ 7.90 hrs, Volume= 0.019 af Outflow = 0.01 cfs @ 9.47 hrs, Volume= 0.019 af, Atten= 76%, Lag= 94.6 min Discarded = 0.01 cfs @ 9.47 hrs, Volume= 0.019 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routed to Reach 24R : POST Routing by Dyn-Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 483.21' @ 9.47 hrs Surf.Area= 301 sf Storage= 266 cf Flood Elev= 483.50' Surf.Area= 342 sf Storage= 321 cf Plug-Flow detention time= 378.4 min calculated for 0.019 af (100% of inflow) Center-of-Mass det. time= 379.2 min ( 1,044.8 - 665.6 ) Volume Invert Avail.Storage Storage Description #1 482.50' 138 cf Open Storage (Prismatic) Listed below (Recalc) #2 481.50' 7 cf Growing Medium (Prismatic) Listed below (Recalc) 67 cf Overall x 10.0% Voids #3 476.50' 85 cf Rock Chamber (Prismatic) Listed below (Recalc) 335 cf Overall - 92 cf Embedded = 243 cf x 35.0% Voids #4 477.50' 92 cf 36.0" Round Pipe Storage - 36" Inside #3 L= 13.0' 321 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 482.50 67 0 0 483.50 208 138 138 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 481.50 67 0 0 482.50 67 67 67 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 476.50 67 0 0 481.50 67 335 335 Device Routing Invert Outlet Devices #1 Discarded 476.50'1.980 in/hr Infiltration through native soil over Surface area #2 Primary 483.49'3.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Type IA 24-hr 2-Year Rainfall=3.30"5365 Spiker Storm BAW-sdm-10-24-2023 Printed 1/3/2024Prepared by A&O Engineering LLC Page 33HydroCAD® 10.20-2g s/n 04993 © 2022 HydroCAD Software Solutions LLC Discarded OutFlow Max=0.01 cfs @ 9.47 hrs HW=483.21' (Free Discharge) 1=Infiltration through native soil (Exfiltration Controls 0.01 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=476.50' TW=0.00' (Dynamic Tailwater) 2=Orifice/Grate ( Controls 0.00 cfs) Pond 22P: Infiltration Rain Garden #3 Inflow Outflow Discarded Primary Hydrograph Time (hours)484644424038363432302826242220181614121086420Flow (cfs)0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Inflow Area=0.073 ac Peak Elev=483.21' Storage=266 cf 0.06 cfs 0.01 cfs0.01 cfs 0.00 cfs