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HomeMy WebLinkAboutWPO202300009 Calculations 2023-03-01Biscuit Run Park: Phase is Entrance and Parking WPO Plan County of Albemarle, Virginia ENGINEERING CALCULATIONS Prepared for: Albemarle County 401 McIntire Road Charlottesville, Virginia 22902 OF P NO 97088 2?�20 23 G ZONAL F'% Prepared by: I An WoomLy ENGINEERING 210 5th Street NE Charlottesville, Virginia 22902 February 10, 2023 Revised: February 27, 2023 Woolley Engineering Biscuit Run Park: Phase la Entrance and Parking Job # 22120 WPO Plan TALE OF CONTENTS DIVISION t - Stormwater Management Summary page 1 Introduction Method of Analysis Assumptions Stormwater Management Analysis Summary and Conclusions Stormwater Management Apendix page 6 Pre -Construction Drainage Area Exhibit Post -Construction Drainage Area Exhibit HydroCAD Reports for Point of Interest Analysis VRRM Spreadsheet Woolley Engineering Biscuit Run Park: Phase la Entrance and Parking Job # 22120 WPO Plan Division i - Stormwater Management Woolley Engineering Biscuit Run Park: Phase ]a Entrance and Parking Job 4 22120 WPO Plan Introduction• The engineering calculations contained within this report support the WPO plan that has been prepared by Anhold Associates and Woolley Engineering for Phase la of Biscuit Run Park. The calculations and support material demonstrate that the project meets both water quality standards and water quantity requirements for new development. This report has been prepared on behalf of The County of Albemarle Facilities Planning & Construction Department in support of the development of the Biscuit Run Park project in Albemarle County, Virginia. Biscuit Run Park is located along Scottsville Road (Rt 20) within the Scottsville Magisterial District of the County of Albemarle. The County has entered a 99-year property lease agreement with the Commonwealth of Virginia Department of Conservation & Recreation to enable the property to be developed as a County Park. A park Master Plan was prepared by Anhold Associates and Woolley Engineering and was adopted by the County Board of Supervisors. The combination of parcels encompassing the park totals 1194.78 acres and is zoned Rural Areas (RA). The Park will likely be brought on-line in phased development. The current WPO Plan improvements are for phase 1 a of the development. Phase 1 a improvements for the park include: select tree clearing and mulching of the downed trees. The pre -construction conditions of the site are in various states of vegetation covering three vacant parcels. Stormwater from the site currently conveys via overland flow. There are no significant site improvements or stormwater treatment facilities existing on the site. There are three existing stormwater pipes that convey runoff off -site to the east side of Scottsville Road (Route 20). The flow from these conveyance pipes combine with flow from the east side of Scottsville Road in a channel before conveying through an existing box culvert back onto the Biscuit Run Park property. The proposed plan for phase la of the park includes mulching existing site trees and conveying the stormwater via sheet flow to each point of interest. A shallow stormwater quantity control basin is being proposed within an existing drainage swale in drainage area 4 to meet energy balance, 1-YR 24-HR design storm, requirements. The location of the shallow basin was chosen based on site conditions and general topography. Albemarle County intends to purchase offsite nutrient credits to meet stormwater management regulations for water quality under VSMP regulation 9VAC25-870-65 and Albemarle County Code Section 17-502.A.2. The proposed stormwater management plan meets water quantity regulations under 9VAC25-870-66B.3.a. for channel protection by meeting energy balance at the six individual chosen points of interest. The proposed stormwater plan meets flood protection quantity regulations under 9VAC25-870-66 C.3.D. by maintaining sheet flow prior to meeting the point of interest. Woolley Engineering Biscuit Run Park: Phase la Entrance and Parking Job # 22120 WPO Plan Method of Analysis: General Method of Analysis: The six points of interest for our analysis were chosen as the point where all drainage from each drainage divide converge. These points allow for the quantification of stormwater including all new improvements. Adjacent property information, field -run survey, and County GIS documents were utilized to develop the limits of each drainage divide. Rain data was obtained from NOAA National Weather Service Data. Soil information was obtained from the United States Department of Agriculture Natural Resources Conservation Service for soil surveys. As determined by USDA resources, the soil type for the project area is fully within hydrologic soil group type B. Stormwater Quantity Pre -construction and post -construction flows were modelled using HydroCAD software to demonstrate that this project meets energy balance and State stormwater regulations. The projected flow rates for the 1-YR 24-HR storm were then analyzed to confirm that energy balance requirements will be achieved with the proposed site improvements. HydroCAD Reports showing the peak flow rates for each of the six points of interest can be found in the Stormwater Appendix on plan sheet C-601. Stormwater Quality A VRRM spreadsheet provided by the Virginia Department of Environmental Quality was utilized to determine the amount of pollutant removal required to meet stormwater quality compliance under the State regulations. Impervious and pervious surfaces for pre -construction and post -construction site conditions were quantified and entered into the Standard DEQ VRRM spreadsheet for new development. This method of evaluation allowed us to ensure that State required stormwater quality benchmarks are being met with the proposed site improvements. A copy of the VRRM spreadsheet for this project can be found in the Stormwater Management Appendix. Woolley Engineering Biscuit Run Park: Phase la Entrance and Parking Job # 22120 WPO Plan q Assumptions' The Lag/CN method was used within the HydroCAD software to determine the time of concentration (Tc) values for each drainage area. A curve number (CN) of 98 was assumed for all impervious surfaces, a CN of 48 was assumed for the proposed cleared and mulched cover area, and a CN of 55 was assumed for all wooded areas. These assumptions were based on soil information obtained from the U.S. Department of Agriculture (USDA) web soil survey, the USDA National Engineering Handbook and with the recommendations found in the Virginia Stormwater Management Handbook Volume II, Chapter 4, Table 4-6b for agricultural lands. The curve number for the proposed new cleared land area with intermixed mulched cover was interpolated and based upon similar land cover examples for brush -weed -grass mixture in hydrologic group type B soils. The existing wooded area of the park was primarily pasture land as recently as 15 years ago. Due to the abundance of pioneer tree species that populates the park today, there is currently a good amount of young undergrowth shrub and meadow grasses interspersed amongst the wooded areas. The existing trees to be cleared will be transformed into mulch containing a mixture of cedars, pines, and deciduous trees. Proposed erosion and sediment control measures for the tree clearing would combine the mulched areas with new temporary grass seeding. The plan specifies a post -construction tree clearing area with undergrowth shrub, new and existing grasses and the addition of a fairly uniform spreading of wood mulch. Woolley Engineering Biscuit Run Park: Phase la Entrance and Parking Job # 22120 WPO Plan E Analysis: Water Quantity: Channel Protection: Pre -construction and post -construction peak flows and runoff volumes were calculated at each point of interest. See the summary for these calculations on plan sheet C-602. Drainage conveyed at each point of interest is shown to meet energy balance in the post - construction condition of the site. The energy balance at the point of interest for the 1- YR, 24-hr design storm is being met with the proposed site improvements. This satisfies VSMP regulations under Part II B, Water Quantity (9VAC25-870-66.B.3.a.). Flood Protection: The post -construction condition of the site includes 9.9 acres of cleared land area. The cleared area will contain a fairly uniform spreading of mulch. This intermixed mulch application will impact the SCS Curve Number for overland flow prior to reaching the point of interest. The intermixed mulch application will not impede existing sheet flow of to each point of interest. Sheet flow satisfies VSMP regulations under Part II B, Water Quantity (9VAC25-870-66.C.3.D). Water Quality: The Owner (Albemarle County, Lessee) is eligible to purchase offsite nutrient credits under Albemarle County Code, Chapter 17, Sec. 17-502.A.2. due to the total post - construction pollution control (measured in phosphorus) requirement totaling less than 10 lb/yr. The County intends to purchase offsite stormwater nutrient credits to meet State Regulated stormwater quality requirements. The County will purchase nutrient credits to meet Water Quality (9VAC25-870-65). The DEQ VRRM spreadsheet summary can be found in the Stormwater Appendix. The proposed improvements require 0.46 lb/yr of total phosphorus nutrient loads. Total Phosphorus Nutrient Total Phosphorus Nutrient Reserved Nutrient Credits Required Credits to be Purchased Credits for Future Build - out 0.46lb/ r 3.0lb/ r 2.54lb/ r Source: VRRM Spreadsheet (found in Stormwater Management Appendix) Woolley Engineering Biscuit Run Park: Phase la Entrance and Parking Job # 22120 WPO Plan Summary and Conclusions: This plan meets the VSMP regulations under Part II B, Water Quantity for Channel Protection (9VAC25-870-66 13.3.a.) by meeting energy balance requirements for the 1- YR, 24-HR design storm. The plan meets VSMP regulations under Part II B, Water Quantity for Flood Protection (9VAC25-870-66.C.3.D.) by maintaining sheet flow prior to each point of analysis. This plan also meets the VSMP regulations under Part II B, Water Quality (9VAC25- 870-65) with the purchase of offsite stormwater nutrient credits. Woolley Engineering Biscuit Run Park: Phase la Entrance and Parking Job # 22120 WPO Plan �7 Stormwater Management Appendix Woolley Engineering Biscuit Run Park: Phase ]a Entrance and Parking Job 4 22120 WPO Plan 100 Stormwater Management Narrative: Water Quantity: Pre -Construction Site Conditions: There are six drainage divides located within the project area. Stormwater quantity was evaluated at each of these points of interest for pre -construction and post -construction conditions. Point of Interest 1: Drainage area 1 drains via overland flow to the point of interest. In the pre -construction condition the drainage area is wooded with a mix of deciduous and non -deciduous trees. Point of Interest 2: Drainage area 2 drains via overland flow to the point of interest prior to entering an exisitng 24" CMP. This pipe conveys under the existing roadway. In the pre -construction condition the drainage area is wooded with a mix of deciduous and non -deciduous trees. A portion of the existing roadway for Avon Street Ext. and Scottsville Road (Route 20) converge at point of interest 2. Point of Interest 3: Drainage area 3 drains via overland flow to the point of interest. This point of interest is located prior to entering an existing 21" DI pipe. This pipe conveys under the existing roadway. In the pre -construction condition the drainage area is wooded with a mix of deciduous and non -deciduous trees. A portion of the existing roadway for Scottsville Road (Route 20) conveys through point of interest 3. Point of Interest 4: Drainage area 4 drains via overland flow to the point of interest prior to entering an exisitng 18" CMP. This pipe conveys under the existing roadway. In the pre -construction condition the drainage area is wooded with a mix of deciduous and non -deciduous trees. A portion of the existing roadway for Scottsville Road (Route 20) conveys through point of interest 4. Point of Interest 5: Drainage area 5 drains via overland flow to the point of interest prior to entering an unnamed tributary. In the pre -construction condition the drainage area is wooded with a mix of deciduous and non -deciduous trees. Point of Interest 6: Drainage area 6 drains via overland flow to the point of interest prior to entering an unnamed tributary. In the pre -construction condition the drainage area is wooded with a mix of deciduous and non -deciduous trees. A portion of the existing roadway for Scottsville Road (Route 20) conveys through point of interest 6. Post -Construction Site Conditions: Post -construction improvements include tree clearing and mulching 9.8 acres of the site. The post -construction conditions of the site were evaluated at each point of interest to ensure State Regulations are being met. The following improvements were made to the existing drainage pattern in order to meet energy balance requirements: Point of Interest 1: The post -construction condition contains 0.73 acres of mulched area. Post -construction drainage for drainage area 1 flows through the point of interest before travelling overland and ultimately entering an existing culvert. The overall drainage pattern will remain relatively unchanged from the pre -construction to the post -construction condition. Point of Interest 2: The post -construction condition contains 1.48 acres of mulched area. Post -construction drainage for drainage area 2 flows through the point of interest before entering the existing 24" CMP. The overall drainage pattern will remain relatively unchanged from the pre -construction to the post -construction condition. Point of Interest 3: The post -construction condition contains 4.63 acres of mulched area. Post -construction drainage for drainage area 3 flows through the point of interest before entering the existing 21" DI pipe. The overall drainage pattern will remain relatively unchanged from the pre -construction to the post -construction condition. Point of Interest 4: The post -construction condition contains 0.89 acres of mulched area. Post -construction drainage for drainage area 4 flows through the point of interest before entering the existing 18" CMP. A shallow stormwater quantity control device will be installed to reduce stormwater flow within the existing swale. This device is located just upstream of the right-of-way line within the existing swale for drainage area 4. See C-601 for location information. See C-612 for device details. Point of Interest The post -construction condition contains 0.82 acres of mulched area. Post -construction drainage for drainage area 5 flows through the point of interest before entering the existing tributary to Biscuit Run. The overall drainage pattern will remain relatively unchanged from the pre -construction to the post -construction condition. Point of Interest 6: The post -construction condition contains 1.28 acres of mulched area. Post -construction drainage for drainage area 6 flows through the point of interest before entering the existing tributary to Biscuit Run. The overall drainage pattern will remain relatively unchanged from the pre -construction to the post -construction condition. Method of Analysis: The six points of interest for our analysis were chosen as the point where all drainage from each drainage divide converge. These points allow for the quantification of stormwater including all new improvements. A shallow stormwater quantity control basin is being proposed on -site to meet State regulations and energy balance. Adjacent property information, field -run survey, and County GIS documents were utilized to develop the limits of each drainage divide. Rain data was obtained from NOAA National Weather Service Data. Soil information was obtained from the United States Department of Agriculture Natural Resources Conservation Service for soil surveys. A curve number (CN) of 98 was assumed for all impervious surfaces, a CN of 48 was assumed for the proposed cleared and mulched cover area, and a CN of 55 was assumed for all wooded areas. These assumptions were based on soil information obtained from the U.S. Department of Agriculture (USDA) web soil survey, the USDA National Engineering Handbook and with the recommendations found in the Virginia Stormwater Management Handbook Volume II, Chapter 4, Table 4-6b for agricultural lands. The curve number for the proposed new cleared land area with intermixed mulched cover was interpolated and based upon similar land cover examples for brush -weed -grass mixture in hydrologic group type B soils. The existing wooded area of the park was primarily pasture land as recently as 15 years ago. Due to the abundance of pioneer tree species that populates the park today, there is currently a good amount of young undergrowth shrub and meadow grasses interspersed amongst the wooded areas. The existing trees to be cleared will be transformed into mulch containing a mixture of cedars, pines, and deciduous trees. Proposed erosion and sediment control measures for the tree clearing would combine the mulched areas with new temporary grass seeding. The plan specifies a post -construction tree clearing area with undergrowth shrub, new and existing grasses and the addition of a fairly uniform spreading of wood mulch. Pre -construction and post -construction flows were modelled using HydroCAD software to demonstrate that this project meets energy balance and State regulations. The modelling software projected flow rates were then analyzed to confirm that energy balance requirements will be achieved with the proposed site improvements. Summary: Channel Protection: Pre -construction and post -construction peak flows and runoff volumes were calculated at each point of interest. See the summary for these calculations on plan sheet C-602. Drainage conveyed at each point of interest is shown to meet energy balance in the post -construction condition of the site. The energy balance at the point of interest for the 1-YR, 24-hr storm is being met with the proposed site improvements. This satifies VSMP regulations under Part II B, Water Quantity (9VAC25-870-66.B.3.a.). Flood Protection: The post -construction condition of the site includes 9.9 acres of cleared land. The cleared area will contain a fairly uniform spreading of mulch. This mulched area will act as an erosion control and stormwater measure. The mulch will continue to sheet flow the stormwater to the point of interest. Sheet flow satisfies VSMP regulations under Part II B, Water Quantity (9VAC25-870-66.C.3.D). "/10I I I I V GI VI Water Quality: Pre -Construction Site Conditions: There are no existing stormwater quality measures located on -site. Post -Construction Site Conditions: The Owner (Albemarle County, Lesee) is eligible to purchase offsite nutrient credits under Albemarle County Code, Chapter 17, Sec. 17-502.A.2. due to the total post -construction pollution control (measured in phosphorus) requirement totalling less than 10 lb/yr. The County intends to purchase offsite stormwater nutrient credits to meet State Regulated stormwater quality requirements. Method of Analysis: Impervious and pervious surfaces for pre -construction and post -construction site conditions were quanitfied and entered into the DEQ VRRM spreadsheet. This allowed us to ensure that State required stormwater quality benchmarks are being met with the proposed site improvements. Summary: The County will purchase nutrient credits to meet Water Quality (9VAC25-870-65). The DEQ VRRM spreadsheet summary can be found on sheet C-630 of the plan set. The proposed improvements require 0.46 Ib/yr of total phosporus nutrient loads. NOTE: APPROVED INITIAL SITE PLAN SDP202100015 ALBEMARLE COUNTY CLIENT 401 MCI NTIRE ROAD CHARLOTTESVILLE, VA 22901 ADDRESS BISCUIT RUN PHASE 1A, ENTRANCE AND PARKING PROJECT WPO - CLEARING SUBMISSION ANHOLD ASSOCIATES 8311 Rockfish Gap Turnpike Greenwood, VA 22943 434.882.3420 anholdla.com WOOLLEY ENGINEERING 210 5th Street NE Charlottesville, VA 22902 434.973.0045 wool ley-eng.com TH OF v\ G 'RTC W. 1900LLEY LTC. NO. 3708e 2-27-2023 WIONAL REVISION: NO. DESCRIPTION DATE 01 REVISED WPO CLEARING PLAN 02.27.23 SCALE: 11I = 1001 SHEET NAME: PRE -CONSTRUCTION DRAINAGE DIVIDES SHEET NUMBER: C-600 February 10, 2023 dmwingl.Qwg © Anhold Associates 2023 Sheet 14 of 17 100 3 2 n POINT OF INTEREST 3 POINT OF INTEREST 2 POINT OF INTEREST 1 Energy Balance Equation Summary Biscuit Run Park: 1-Year 24-Hour Design Storm: Qdeveloped = I.F.' )Qpre-developed' RVpre-developed)/RVdeveloped Point of Interest Analysis: Qpre-developed 1.23 cfs RVpre-developed 0.34 of RVdeveloped 0.26 of I.F. 0.80 Max Allowed Qdeveloped 1.26 cfs Peak Qdeveloped Achieved 0.71 cfs Energy Balance Equation Summary Biscuit Run Park: 1-Year 24-Hour Design Storm: Qdeveloped = I.F.' (Qpre-developed' RVpre-developed)/RVdeveloped Point of Interest Analysis: Qpre-developed 1.02 cfs RVpre-developed 0.20 of RVdeveloped 0.16 of I.F. 0.80 Max Allowed Qdeveloped 1.01 cfs Peak Qdeveloped Achieved 0.63 cfs Energy Balance Equation Summary Biscuit Run Park: 1-Year 24-Hour Design Storm: Qdeveloped = I.F.' (Qpre-developed' RVpre-developed)/RVdeveloped Point of Interest Analysis: Qpre-developed 0.18 cfs RVpre-developed 0.04 of RVdeveloped 0.03 of I.F. 0.80 Max Allowed Qdeveloped 0.18 cfs Peak Qdeveloped Achieved 0.09 cfs 6 5 4 POINT OF INTEREST 6 POINT OF INTEREST 5 POINT OF INTEREST 4 Energy Balance Equation Summary Biscuit Run Park: 1-Year 24-Hour Design Storm: Qdeveloped = I.F.' )Qpre-developed' RVpre-developed)/RVdeveloped Point of Interest Analysis: Qpre-developed 0.40 cfs RVpre-developed 0.07 of RVdeveloped 0.05 of I.F. 0.80 Max Allowed Qdeveloped 0.45 cfs Peak Qdeveloped Achieved 0.18 cfs Energy Balance Equation Summary Biscuit Run Park: 1-Year 24-Hour Design Storm: Qdeveloped = I.F.' )Qpre-developed ` RVpre-developed)/RVdeveloped Point of Interest Analysis: Qpre-developed 0.39 cfs RVpre-developed 0.13 of RVdeveloped 0.12 of I.F. 0.80 Allowed Qdeveloped F 0.35 cfs k Qdeveloped Achieved 0.30 cfs Energy Balance Equation Summary Biscuit Run Park: 1-Year 24-Hour Design Storm: Qdeveloped = I.F.' )Qpre-developed' RVpre-developed)/RVdeveloped Point of Interest Analysis: Qpre-developed 0.59 cfs RVpre-developed 0.18 of RVdeveloped 0.15 of I.F. 0.80 Max Allowed Qdeveloped 0.58 cfs Peak Qdeveloped Achieved 0.40 cfs ti"�Z HATCHED AREA DENOTES APPROXIMATE LIMITS OF MULCHING POST -CONSTRUCTION DRAINAGE DIVIDES (TYP) HATCHED AREA DENOTES APPROXIMATE LIMITS OF MULCHING DRAINAGE AREA TOTAL AREA (AC) TOTAL MULCHED AREA (AC) 1 2.40 0.73 2 8.16 1.48 3 17.47 4.63 4 10.69 0.89 5 7.79 0.82 6 2.76 1.28 LIMITS OF CLEARING (TYP) 0 0 200 POST CONSTRUCTION MULCHING AREA KEY VA PROPERTY LINE (TYP) ALBEMARLE COUNTY CLIENT 401 MCI NTIRE ROAD CHARLOTTESVILLE, VA 22901 ADDRESS BISCUIT RUN PHASE 1A, ENTRANCE AND PARKING PROJECT WPO - CLEARING SUBMISSION ANHOLD ASSOCIATES 8311 Rockfish Gap Turnpike Greenwood, VA 22943 434.882.3420 anholdla.com WOOLLEY ENGINEERING 210 5th Street NE Charlottesville, VA 22902 434.973.0045 wool ley-eng.com 5�TH OF v\ G 'RTC W. WOOLLEY LTC. NO. 3708e 2-27-2023 WIONAL REVISION: NO. DESCRIPTION DATE 01 REVISED WPO CLEARING PLAN 02.27.23 SCALE: 1'I = 100, SHEET NAME: POST -CONSTRUCTION DRAINAGE DIVIDES SITE ENERGY BALANCE SUMMARY 1-YR, 24-HR DESIGN STORM SHEET NUMBER: C-601 February 10, 2023 dmwingl.Qwg © Anhold Associates 2023 Sheet 15 of 17 PRE1 PRE-1 Sub4 Reach Aon Llflk 230207_DAl BISCUIT RUN PARK PH 1A - DA 1 ANALYSIS Type 1124-hr 1-YR Rainfall=3.04" Prepared by Woolley Engineering HydroCAD® 10.10-3a s/n 11332 © 2020 HydroCAD Software Solutions LLC Page 9 Summary for Subcatchment PRE1: PRE-1 Runoff = 0.18 cfs @ 12.21 hrs, Volume= 0.041 af, Depth= 0.21" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 1-YR Rainfall=3.04" Area (ac) CN 0.000 98 Paved parking, HSG B 2.400 55 Woods, Good, HSG B 0.000 48 Brush, Good, HSG B (MULCH) 2.400 55 Weighted Average 2.400 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.7 980 0.1200 0.92 Lag/CN Method, Subcatchment PRE1: PRE-1 Hydrograph I I --r-r--r-T--'-----�__r-r-r__r--I--r-r-r--r--r--I--r-r-r--r-- ■RUnoff - 0..10 _-r_-T -T -r -7 -T -T r -- -T -r -r-r -r IO Y�J 0.18 0.17 0.16 --'-___________ I I I I 0.150-14 - -'- -I 0.13 ---------'--- 0.12 o.,, v --L-J--J--1 3 0.1 LL 0.09 0.08 0.07 006 0.05 0 04 0.03 ' 0.02 -'i--'i'I--T-- T --r--i----,-- TA--�Ii/-p-i pI �I s ,rT-/r�-�-I --'i ---- -- -- --' I--- -- -- I�-�ii�'-IFaiFI fa[14&WF1'- I r = __-l-- n6ff'Afee-2.40aa1b= I I I I I I I I I I I --------;--;-ujngff_1tQllymje=O:Q�=# -- -- -- --; -- -- -- anof# Dep#Fy:;E}2 , I--J--1--1--L--L_-I--J--1--L--L--I-__I_____L--L--L- I I I I I I I I I I I -- -- --; -- - -- ;-- ; Tope= :1 0y T I I I I I I I I I I I I I 1 c t I -y-- -- --------- -- --t--�l -mm- I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I -r--r-�--r--r--r--r--r-T--r--r--r- I I I I I I I I I I Time (hours) POST1 POST-1 Subcat Reach Aon Llflk 10 230207_DAl BISCUIT RUN PARK PH 1A - DA 1 ANALYSIS Type 1124-hr 1-YR Rainfall=3.04" Prepared by Woolley Engineering HydroCAD® 10.10-3a s/n 11332 © 2020 HydroCAD Software Solutions LLC Page 11 Summary for Subcatchment POST1: POST-1 Runoff = 0.09 cfs @ 12.31 hrs, Volume= 0.032 af, Depth= 0.16" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 1-YR Rainfall=3.04" Area (ac) CN 0.000 98 Paved parking, HSG B 1.680 55 Woods, Good, HSG B 0.730 48 Brush, Good, HSG B (MULCH) 2.410 53 Weighted Average 2.410 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 18.6 980 0.1200 0.88 Lag/CN Method, Subcatchment POST1: POST-1 Hydrograph I__ __ __I__ I__ __ _____I_ _ i__�__i__ i__L__1__ i__.. � _�__i__�_ i__�__i__i__ ■Runoff i I 0.09 cfs I i j L L I I I I L I i I L 0.085 ---J--i--i--� 0.08 0.075 _1--i- 0.06 0.055 _ __i_-'_ a c 0.045 LL 0_04 0.035 I I I I I 0.03 0.025 I I I I I 0.02 0.015 0.01 r !1 11I14 1 I 1 I I L L- ;-Tylpe'-N'24-hr-- -J--1--L--1-- 1--J--1--L--I I J 1 L I J 1__� f-Y1�-1� in 11=;3.44, I -Rtindff-Ater=2.410 ad- - -�qi {�i Ve611:40.t 61 - --- --I-- I-- I-- I ---- 1 1- 1 filolnr L-_en",- _ _8_ fl_'-_ - ___ _______________S/�_�+^_/u� _ C min- 1-- 1 -- 1 1 I 1 Y�11 ___________________________________ 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 r__r__r__1__r__r__�__1__4__r__r__1__�__7__r__ 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 I I I I I I I 1 I I I I I I Time (horns) 11 PRE2 PRE-2 Subcat Reach Aon Llflk 12 230207_DA2 BISCUIT RUN PARK PH 1A - DA 2 ANALYSIS Type 1124-hr 1-YR Rainfall=3.04" Prepared by Woolley Engineering HydroCAD® 10.10-3a s/n 11332 © 2020 HydroCAD Software Solutions LLC Page 13 Summary for Subcatchment PRE2: PRE-2 Runoff = 1.02 cfs @ 12.31 hrs, Volume= 0.195 af, Depth= 0.29" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 1-YR Rainfall=3.04" Area (ac) CN 0.480 98 Paved parking, HSG B 7.680 55 Woods, Good, HSG B 8.160 58 Weighted Average 7.680 94.12% Pervious Area 0.480 5.88% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 26.2 1,558 0.0988 0.99 Lag/CN Method, Subcatchment PRE2: PRE-2 Hydrograph ■Runoff 1.02 cfs r Ype 11;24-Fllr 1-YR R'ainfa11:;3.04 Rtinbff Aret=8.1:60 alp rkOnO'f(V911tsm6=;0. j 9$ elf kunoff:De0'h40.29"' M F16 W, Ldnath=1,S58' $100=0-0�98,8 7 Tc=16 . min CN=58 Time (hours) 13 POST2 POST-2 Subcat Reach Aon Llflk 14 230207_DA2 BISCUIT RUN PARK PH 1A - DA 2 ANALYSIS Type 1124-hr 1-YR Rainfall=3.04" Prepared by Woolley Engineering HydroCAD® 10.10-3a s/n 11332 © 2020 HydroCAD Software Solutions LLC Page 15 Summary for Subcatchment POST2: POST-2 Runoff = 0.63 cfs @ 12.37 hrs, Volume= 0.157 af, Depth= 0.23" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 1-YR Rainfall=3.04" Area (ac) CN 0.480 98 Paved parking, HSG B 6.200 55 Woods, Good, HSG B 1.480 48 Brush, Good, HSG B (Mulch) 8.160 56 Weighted Average 7.680 94.12% Pervious Area 0.480 5.88% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 27.6 1,558 0.0988 0.94 Lag/CN Method, Subcatchment POST2: POST-2 Hydrograph -- -- -- -- -- I I I I I I I I I I I I _I__I 0.7 -- - 0.63cfs - 1----;--; ----------;--1 --II-- 1----;-- --11-- 6.65------;--;--1--;--;--;--------------- 0.8 '1r--yp�11;2r --, -,--,- - --------- I R� 0.55F-YRinTatfN3:04"- --I--J--J-- --1--J--1--1--L--1--I--1--1--1--L--1---I--1--1--L--1-- 0.5 " 11 Rtlin6ff'IAteA=8.1:60 alp " I I I I I I I I I I�/I�{{I /I� ��I�Ip ,I/� Cy/ .�I{ 0.45-I--;__I__. __ - a'Y.•rV1i�M'•aY=�'V. JY-Of r_ r_ 6.4 - -- -- --=----=--=----------=--I�at�aii#-111DepFi�0:2-37- 3 0.35 LL 0.3 I I I I I I I I I I I I I I /� 6.25 " $To11p6=0.0080'r --r-1----T------T--T--r 1 1 1--7--T--r I T--T-.-i- 02 1 1 I I I I C /6 min ------------- -------------------------------------------- 1 1 1 1 1 1 1 6.15 I 1 1 I I I 1 1 I I I 1 1 1 I CNr56- _I 0., _1 _1 _--T -h _1 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hove) ■ Runoff 15 PRE3 PRE-3 Subcat Reach Aon Llflk 16 230207_DA3 BISCUIT RUN PARK PH 1A - DA 3 ANALYSIS Type 1124-hr 1-YR Rainfall=3.04" Prepared by Woolley Engineering HydroCAD® 10.10-3a s/n 11332 © 2020 HydroCAD Software Solutions LLC Page 17 Summary for Subcatchment PRE3: PRE-3 Runoff = 1.23 cfs @ 12.47 hrs, Volume= 0.337 af, Depth= 0.23" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type II 24-hr 1-YR Rainfall=3.04" Area (ac) CN 0.290 98 Paved parking, HSG B 17.180 55 Woods, Good, HSG B 17.470 56 Weighted Average 17.180 98.34% Pervious Area 0.290 1.66% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 33.8 1,900 0.0905 0.94 Lag/CN Method, Subcatchment PRE3: PRE-3 Hydrograph ■ RunoH 1.23 cfs T 'p411;24-hr 1-I Rai nfa11:;3.04 Runoff Ard&17.470 at ROnpff'1Vp1LPm6=;0.$37 Of kunoff :DepthT0.23"' F16W, Ldnath=1, 3900' $Iop�=0-000',5 7' Tc=33 8min CN-56 12 Time (hours) MA POST3 POST-3 Subcat Reach Aon Llflk IM 230207_DA3 BISCUIT RUN PARK PH 1A - DA 3 ANALYSIS Type 1124-hr 1-YR Rainfall=3.04" Prepared by Woolley Engineering HydroCAD® 10.10-3a s/n 11332 © 2020 HydroCAD Software Solutions LLC Page 19 Summary for Subcatchment POSTS: POST-3 Runoff = 0.71 cfs @ 12.61 hrs, Volume= 0.264 af, Depth= 0.18" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Type II 24-hr 1-YR Rainfall=3.04" Area (ac) CN 0.290 98 Paved parking, HSG B 12.560 55 Woods, Good, HSG B 4.630 48 Brush, Good, HSG B (Mulch) 17.480 54 Weighted Average 17.190 98.34% Pervious Area 0.290 1.66% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 35.6 1,900 0.0905 0.89 Lag/CN Method, 08 0.75 1 I 0.1 _1 0.7 0.65 li li 0.8 0.55 0.5 I I I I 0.45 v 6.4 I I I I n 0.35 ' 0.3 0.25 I I I I 62 0.15 01 Subcatchment POST3: POST-3 Hydrograph -J--1--1--L--1---I--,--1--1--L--1---I--1--1--L--1-- fs T__r__r__i__T__T__r__r_____i__T_1_r//�_ r_ I I I I I I I I I I _T�IIp�JI;�!_ Jar I I I I I I I I IA ��II//pI pI NI �,�I',rI I/��I --i--41 R-Ra111 aRq$04"- I I I I I I I I I I I I I I I --;- ---'I___I-RudoffArda"T.48Qad- n_/�1�)/�IL�)_�_�L�_J/r_��I_1(,-_ r__T__r__r__r_ -I�VII IDep4lwV.11 O,, ----T--T--r--i --I-- I- FFdw LPin_O1.17=7>9VV,- __F __I___II__ I__ I__� __f-_lpe IT�IDJLil,L- �Inm- __L_�__L__I__ CN�54 T__r__r__r_ I I I I I I I I I I I I I I I I I I I I I I I I I 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hove) ■ Runoff 19 PRE4 PRE-4 Subcat Reach Aon Llflk 20 230207_DA4 BISCUIT RUN PARK PH 1A - DA 4 ANALYSIS Type 1124-hr 1-YR Rainfall=3.04" Prepared by Woolley Engineering HydroCAD® 10.10-3a s/n 11332 © 2020 HydroCAD Software Solutions LLC Page 21 Summary for Subcatchment PRE4: PRE-4 Runoff = 0.59 cfs @ 12.51 hrs, Volume= 0.183 af, Depth= 0.21" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 10.00-48.00 hrs, dt= 0.01 hrs Type II 24-hr 1-YR Rainfall=3.04" Area (ac) CN 0.090 98 Paved parking, HSG B 10.600 55 Woods, Good, HSG B 10.690 55 Weighted Average 10.600 99.16% Pervious Area 0.090 0.84% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 33.6 1,685 0.0794 0.84 Lag/CN Method, Subcatchment PRE4: PRE-4 Hydrograph 0.05 0.59 cfs i_I__I_ i_ i_ i_I_ I_i_L_I__I_i_ i_i_I_J_1_ L_L1i�l'-/dJL11_ 0.55 _�_y-I-_�_�_}_L_I__I_a_}-L_�_�_;-L-I--I-;-A-L� I. �\~RIy�M�w•• �. AA� 0.5 AfNP"O-690 -96- 0.45 I I I I I I I I I 0.4 * I~ i•I-1•TM�Y• JJ5••Ji=V•�•YY 0.35 k6nof Depth-FO.21", - Y-I--I-Y-Y-r-I--I-Y-t-r-I-1'Y-r- 0.3 ' ' ' ' ' ' Flbw: Leh th=h ' 685' ---rrr-r-r-rY-r-r-r�-Y-r-r-rY-r-r-I-r-Y-r-r-i 0.25 $'/�0piq it �y ----r-r-r-rT-r-r--1-T-rr--T-r-r-rr-T r t I r T r r 02 -r-r--r-r-I-r-r-r-i-T-r-r-r-r�-r-r-i-r-r-r-r b•'fJ 0.15 I I I I� � i i I I I i i i i i I I I i i I 1 ICN �*5� -r-r-r-i-1---r1-r-r-r-r7-r-r-rr-r-r-r-r..-r-r 01 r- r-r--- - - - - -- r 0.05 I I Time (hours) ■ Runoff 21 Q0101CA POST-4 4 QUANTITY CONTROL BASIN Subcat Reach Aon Llflk 04 230207_DA4 BISCUIT RUN PARK PH 1A - DA 4 ANALYSIS Type 1124-hr 1-YR Rainfall=3.04" Prepared by Woolley Engineering HydroCAD® 10.10-3a s/n 11332 © 2020 HydroCAD Software Solutions LLC Page 23 Summary for Subcatchment POST4: POST-4 Runoff = 0.59 cfs @ 12.51 hrs, Volume= 0.183 af, Depth= 0.21" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 10.00-48.00 hrs, dt= 0.01 hrs Type II 24-hr 1-YR Rainfall=3.04" Area (ac) CN 0.090 98 Paved parking, HSG B 9.710 55 Woods, Good, HSG B 0.890 48 Brush, Good, HSG B (Mulch) 10.690 55 Weighted Average 10.600 99.16% Pervious Area 0.090 0.84% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 33.6 1,685 0.0794 0.84 Lag/CN Method, Subcatchment POST4: POST-4 Hydrograph 0.65 0s0.59 cfs 0.55 -- -A- -A- -- t--YWRainf R:;3.04" 0.5 �I �I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 0.45 I I I I I I yI I��� ������_0- Y•I 0.4 •F I[� ---- - - -- - - -- ;- ; - - -;- ; Fk6naf 6l p--F 0.35 0.3 � �-�-�-r-r-r-i-r-*-r-�-�-T-r-I--�-r-*-r-i-r-r-r-r-�-� LL I FIbw': L'eh�th=;'11685' - ---r-r---r�-r-r----r-r--- r- rr - r -rr-r I I I --r�-r-r-r-rrr-r-r�-r-r-r-r�-r-r-I-r-r �lr%6l Tl_lr I r r r -r-r-r7-r-r--1-T3U n 015 , 01 nnc � I I I i I I I I I I I I I I I I I I I I I I I I I I I I 10 1112 13 1415 16 1718 19 20 2122 23 2425 26 2728 29 3031 32 3334 35 3637 38 39 4041 42 4344 45 4647 48 Time (hove) ■ Runoff 23 230207_DA4 BISCUIT RUN PARK PH 1A - DA 4 ANALYSIS Type 1124-hr 1-YR Rainfall=3.04" Prepared by Woolley Engineering HydroCAD® 10.10-3a s/n 11332 © 2020 HydroCAD Software Solutions LLC Page 24 Summary for Pond 4: QUANTITY CONTROL BASIN Inflow Area = 10.690 ac, 0.84% Impervious, Inflow Depth = 0.21" for 1-YR event Inflow = 0.59 cfs @ 12.51 hrs, Volume= 0.183 of Outflow = 0.40 cfs @ 13.09 hrs, Volume= 0.149 af, Atten= 32%, Lag= 35.1 min Primary = 0.40 cfs @ 13.09 hrs, Volume= 0.149 of Routing by Stor-Ind method, Time Span= 10.00-48.00 hrs, dt= 0.01 hrs Peak Elev= 498.02' C& 13.09 hrs Surf.Area= 1,756 sf Storage= 1,534 cf Plug -Flow detention time=138.7 min calculated for 0.149 of (81 % of inflow) Center -of -Mass det. time=57.2 min ( 1,051.6 - 994.4 ) Volume Invert Avail.Storage Storage Description #1 497.00' 3,249 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation SUrt.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic -feet) (cubic -feet) 497.00 1,230 0 0 498.00 1,756 1,493 1,493 499.00 1,756 1,756 3,249 Device Routing Invert Outlet Devices #1 Primary 498.00' 45.0' long x 6.0' breadth Broad -Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.37 2.51 2.70 2.68 2.68 2.67 2.65 2.65 2.65 2.65 2.66 2.66 2.67 2.69 2.72 2.76 2.83 Primary OutFow Max=0.38 cfs @ 13.09 hrs HW=498.02' (Free Discharge) t1=Broad-Crested Rectangular Weir (Weir Controls 0.38 cfs @ 0.36 fps) 24 230207_DA4 BISCUIT RUN PARK PH 1A - DA 4 ANALYSIS Type 1124-hr 1-YR Rainfall=3.04" Prepared by Woolley Engineering HydroCAD® 10.10-3a s/n 11332 © 2020 HydroCAD Software Solutions LLC Page 25 Pond 4: QUANTITY CONTROL BASIN I- -r-- -r I .Inflow 0.65 Q, rj9 (�`f$-_+_a__a_a___a_a_I_a_a_I_y_+_�_I-a_a_�_I-+_a _I_a_a_�_I_+_�_I_� ■Prima I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ry 0.6 "-.-r-I-7-r-'-"-r-r-'-"-r-'-"-r1";') vlrAFeaG411,6",Ac I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 0.55 rrr'I 1I -r-II -:-I -rI rI- T -TI -II -:-I -rI rI I II -rI -Ir7I^#a kE1a-V; 4YV.VT - I 0.5 -I-T-F -,I -r --- -- -- -- -I- -- r -I-r -I I- -- r-I- -I- - I r-I -I- I 0.45 0.40 cfs 04 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 0.35 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 0.3_,-+-r-,-y- LL I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 0.25 -'- r--r-T-r---r----r---r-r---r---T-r-I-T-r _,_�_ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I i i I i I I I I I I I I I I I I I I I I I I I I I I 0.15 I I I I I I I I I I I I I I I I I I I I I I I I l l l l l l l l l l l l l l l l l l l 01 _1 _'L _I_ I I 1 I I I I I I I I i I I I I I I I I 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 Time (hours) 25 PRE5 PRE-5 Subcat Reach Aon Llflk 26 230207_DA5 BISCUIT RUN PARK PH 1A - DA 5 ANALYSIS Type 1124-hr 1-YR Rainfall=3.04" Prepared by Woolley Engineering HydroCAD® 10.10-3a s/n 11332 © 2020 HydroCAD Software Solutions LLC Page 27 Summary for Subcatchment PRE5: PRE-5 Runoff = 0.39 cfs @ 12.63 hrs, Volume= 0.133 af, Depth= 0.21" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 1-YR Rainfall=3.04" Area (ac) CN 0.000 98 Paved parking, HSG B 7.790 55 Woods, Good, HSG B 7.790 55 Weighted Average 7.790 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 40.5 2,028 0.0737 0.84 Lag/CN Method, iY11eTiF.1MI rT iMIN NU0.1%M 7:N= Hydrograph 044 _-r--1--,--T--r--r--r-�--,--T--r--r--r-,--,--r--r--r--r-,--T--r--r-- ■Runoff 0.42 ----1---- 0.39 cfs -,1- --- - -- -----I-- -- -- --' - 'r --' -- 0.4 0.38 __r_y__y__+__. ,__+__r__r__1__y__+__+__r_ 1 sh 0 36 / I ; 1 I I I I I I I I I I I r -r----1- ImYWRai rlTa1M3:Q4"-- U 0.3 -- -J,----;---- I 028 __r_r__r__ __r_ y�� y -_,__,--i--r--------r1Aff---------�- 0.28 Fj 0.24_ku��{ I I I I I I I I I I I I I _�,I g__I __I__4___T__I/y�_+��____ I© I Yh4�i �,6 V�� 0.22ppIyy 0.z __I r-,--,--,---��� �_yI� /j_I� ---,--T--r--r__I--,--F-16w L6 th-Z,a2W-- 1L , 018-- 0.18 -T--1--T-T-- __I__J__J__1_ I --I I I I I T__r__I--I---I I--T--------1--_-------fir-- 11__1__�__I___11__ ;__1__t_ 1pe—O A7-37- _r__ —I r 0.12 -r---� 0.1 i 1' 0.06 --------- �- ---- -- -------------CN-35-- 1 I 1 1 1 1 1 1 0.02 1 1 1 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hove) MA POST5 POST-5 Subcat Reach Aon Llflk ON 230207_DA5 BISCUIT RUN PARK PH 1A - DA 5 ANALYSIS Type 1124-hr 1-YR Rainfall=3.04" Prepared by Woolley Engineering HydroCAD® 10.10-3a s/n 11332 © 2020 HydroCAD Software Solutions LLC Page 29 Summary for Subcatchment POSTS: POST-5 Runoff = 0.30 cfs @ 12.69 hrs, Volume= 0.118 af, Depth= 0.18" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 1-YR Rainfall=3.04" Area (ac) CN 0.000 98 Paved parking, HSG B 6.970 55 Woods, Good, HSG B 0.820 48 Brush, Good, HSG B (Mulch) 7.790 54 Weighted Average 7.790 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 41.5 2,028 0.0737 0.81 Lag/CN Method, Subcatchment POSTS: POST-5 Hydrograph I I 1 _y _t -i -F -1 -1 -y -1 -f -F -1 -1 J_ . _ _ . _ _ 0.30 cfs _ i 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 LL 0.14 0.12 0.1 0.08 0.06. 0.04 nm I I I I I I I I I I I I I 1 1 ........ ; --1,--1--,--fiM3-. YWRa1n a1OF "- --i--�--�--�---'1--R,rr►csffll���-7 7�9aa1�- 1 I I I 1 1 I I 1 1 1 1 I 1 1 1 -- -- --; -- - -- -- tuno-fl'1Qej)&gO. 8,"` 1 I I I 1 1 I I 1 1 1 1 I 1 1 1 --;- ;---'1-- Fidw L,61!Vtkr l02W- I I 1 1 I I 1 1 1 -----1r--11-----Sf6pe=Q:0737_P- '1 '--1--L--1---1--�--1--+- I I 1 1 1 I I 1 1 1 1 1 1 .1 -'-- -------'-- L--L 'Te- -mtn 1 1 1 1 1 1 1 1 I I 1 I I I 1 1 1 I 1 1 1 1 1 1 1 1 1 1 I 1 1 1 1 1 I I I I I 1 I I I I Time (hours) ■ Runoff 04-1 PRE6 PRE-6 Subcat Reach Aon Llflk 30 230207_DA6 BISCUIT RUN PARK PH 1A - DA 6 ANALYSIS Type 1124-hr 1-YR Rainfall=3.04" Prepared by Woolley Engineering HydroCAD® 10.10-3a s/n 11332 © 2020 HydroCAD Software Solutions LLC Page 31 Summary for Subcatchment PRE6: PRE-6 Runoff = 0.40 cfs @ 12.23 hrs, Volume= 0.066 af, Depth= 0.29" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 1-YR Rainfall=3.04" Area (ac) CN 0.200 98 Paved parking, HSG B 2.560 55 Woods, Good, HSG B 2.760 58 Weighted Average 2.560 92.75% Pervious Area 0.200 7.25% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 21.2 880 0.0610 0.69 Lag/CN Method, Subcatchment PRE6: PRE-6 Hydrograph ,--T--T--r I I T--T--T--r I I T--T--T-T- 0.40 cfs ----- -- -------1-- -- - -------1-- - - - 0.4 0.38 I I I I I --L-----,--L 0.36 0.34 0.32 0 28 --I---I--T--T- _ 0.26 --I_ .0 0.24 ----J--J--1--- 0.22 0.2 LL 018 0.18 0.14 0.12 0.1 0.08 0.06 --L-�--J--1-- ----- Time (hours) ■ Runoff 31 POSTE\,- / POST-6 Subcat Reach Aon Llflk 32 230207_DA6 BISCUIT RUN PARK PH 1A - DA 6 ANALYSIS Type 1124-hr 1-YR Rainfall=3.04" Prepared by Woolley Engineering HydroCAD® 10.10-3a s/n 11332 © 2020 HydroCAD Software Solutions LLC Page 33 Summary for Subcatchment POST6: POST-6 Runoff = 0.18 cfs @ 12.30 hrs, Volume= 0.047 af, Depth= 0.21" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 1-YR Rainfall=3.04" Area (ac) CN 0.200 98 Paved parking, HSG B 1.280 55 Woods, Good, HSG B 1.280 48 Brush, Good, HSG B (Mulch) 2.760 55 Weighted Average 2.560 92.75% Pervious Area 0.200 7.25% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 22.8 880 0.0610 0.64 Lag/CN Method, Subcatchment POSTE: POST-6 Hydrograph 0.2 --L-�—J-- __ __ ____J--J--1--L--I---I--J--1--1--J--I--�--J--1--J--I-- 019._ 0.18 Q 018 ---r--rr-- II r_ 0.17 IIIITr;T �I--r- IyIi1 ITp4 __ rTrr--- I__r__r__ 0.16 __T__TI__r__r_____T_ tea✓f;?, Rai nft11=;3-.0r-_4 1" I 0.15 _-r--I--� -r-T--T--T--r--r--I-- r 0.14 �# _ T r 0.13 -r,--,- rrAu J" I��p 0.12 --------------------------------�-- 6.11 OF2 0.1_H1 3 0.09 1" Il�ndth=asO'- I__J__1__1__L__I___I__J_ 1_ �L LLO __L_J__J__1___ i _ � WY 6.08 -- -JI-- --;--; --JI-- -- --------- -- -- - o e= A010FIr- 0.07 --L---J--'--L -J--J--'--L-------J--'--`- 0.06 .I 0.05 _I 0.04 --r-r--T--r-r --r- - r--r----r-r-r--r--r--I--r r� CN �� 0.03 0.02 --I -T - ---I r-1- T I 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hove) ■ Runoff 33 Virginia Runoff Reduction Method Mrloi DEC! Virginia Runoff Reduction Method New Development Compliance Spreadsheet - Version 3.0 BMP Design Specifications List: 2013 Draft Stds & Specs Site Summary Project Title: Biscuit Run Park Date: 44984 Total Rainfall = 43 inches Site Land Cover Summary A soils !.Soils CSoils DSoils Totals %of Total Forest/Open (acres) 0.00 0.00 0.00 0.00 0.00 0 Managed Turf (acres) 1 0.00 9.90 0.00 0.00 9.90 100 Impervious Cover (acres) 1 0.00 0.00 0.00 0.00 0.00 0 9.90 100 Site Tv and Land Cover Nutrient Loads Site Rv 0.20 Treatment Volume fts 7,187 TP Load (lb/yr) 4.52 TN Load (lb/yr) 32.31 Total TP Load Reduction Required (lb/yr) 0.46 Site Compliance Summary Total Runoff Volume Reduction (ft) 0 Total TP Load Reduction Achieved (lb/yr) 0.00 Total TN Load Reduction Achieved (lb/yr) 0.00 Remaining Post Development TP Load 4.52 (Ib/yr) Remaining TP Load Reduction (lb/yr) 0.46 Required 34 Summary Print Virginia Runoff Reduction Method Worksheet Drainage Area Summary D.A. A D.A. B DA. C DA. D DA. E Total Forest/Open (acres) 0.00 0.00 0.00 0.00 0.00 0.00 Managed Turf(acres) 0.00 0.00 0.00 0.00 0.00 0.00 Impervious Cover (acres) 0.00 0.00 0.00 0.00 0.00 0.00 Total Area(acres) 0.00 0.00 0.00 0.00 0.00 0.00 Drainage Area Compliance Summary D.A. A D.A. B D.A. C DA. D D.A. E Total TP Load Reduced (lb/yr) 1 0.00 0.00 1 0.00 1 0.00 0.00 0.00 TN Load Reduced (Ih/yr) 1 0.00 0.00 1 0.00 1 0.00 0.00 0.00 35 Summary Print Virginia Runoff Reduction Method Wort sheet Runoff Volume amw ON Calculations 1-yearstorm 2-yearstorm 10-yearstorm Tar et Rainfall Even[ in 3.03 3.67 5.55 Drainage Areas RV&CN Drainage AreaA Drainage AreaB Drainage AreaC Drainage Area Drainage Area CN 0 0 0 0 0 RR(fta) 0 0 0 0 0 I -year return period RV we RR lws-inl 0.00 0.00 0.00 0.00 0.00 RV w RR (ws-in) 0.00 0.00 0.00 0.00 0.00 M adjusted 0 0 0 0 0 2-year return period RV was RR (ws-in) 0.00 0.00 0.00 0.00 0.00 RV w RR (wsin) 0.00 0.00 0.00 0.00 0.00 a adjusted 0 0 0 0 0 10-year return period RV wo RR lws-in) 0.00 0.00 0.00 0.00 0.00 RV w RR Iwsin) 0.00 0.00 0.00 0.00 0.00 M adjusted 0 0 0 0 0 36 Summary Print