Loading...
HomeMy WebLinkAboutCC - Storm Drainage Calcs DRAINAGE REPORT Burnside Ridge Estates No. 2 Prepared for: Tresidio Homes, LLC 2973 N. Eagle Rd #110 Eagle, ID 83646 Prepared by: Kimley-Horn and Associates, Inc. 1100 W Idaho Street, Suite 210 Boise, Idaho 83702 193209000 June 25 Copyright©2025,Kimley-Horn and Associates, Inc Drainage Report BURNSIDE RIDGE ESTATES NO . 2 JUNE 23, 2025 Prepared By: Kimley ))) Horn Burnside Ridge Estates No.2 I Final Drainage Report TOC .rune 25 1 193209000 1. Introduction .............................................................................................................................1 1.1 Project Description..................................................................................................................... 1 2. FEMA Floodplain Classification...............................................................................................2 3. Offsite Hydrology ....................................................................................................................3 4. Hydrologic Analysis.................................................................................................................4 4.1 Required Storage Volume..........................................................................................................4 4.2 Provided Storage Volume..........................................................................................................4 5. Proposed Drainage Infastructure.............................................................................................6 5.1 Drainage Conveyance Systems.................................................................................................6 5.3 Finished Floor Elevations And Outfall Requirements................................................................6 6. Summary and Conclusions .....................................................................................................7 7. References .............................................................................................................................8 Appendix A—Tables and Calculations Appendix B — Figures Figure 1 — Site Vicinity Map Figure 2 — FEMA FIRMette Figure 3 — Proposed Conditions Map Burnside Ridge Estates No.2 I Final Drainage Report TOC .rune 25 1 193209000 1 . INTRODUCTION 1 .1 PROJECT DESCRIPTION 1.1.1. Project Name Burnside Ridge Estates No. 2 is a proposed 44 building lot single-family subdivision development located in Meridian, Idaho. The site is located within Section 26 of Township 3 North, Range 1 West, south of Victory Rd and west of Linder Rd. The site is bound to the south by the Calkins Lateral, to the west by existing rural development fronting Rustler PI, to the north by Victory Rd, and to the east by Linder Rd. Refer to Figure 1: Vicinity Map in Appendix B for visual representation of the site location. Burnside Ridge Estates No. 2 is the second phase of a seven-phase subdivision. The proposed drainage infrastructure for Burnside Ridge Estates No. 2 accounts for drainage from subsequent phases where appropriate. 1.1.2. Purpose The purpose of this report is to ensure that the assumptions and methodologies used to develop the on- site hydrologic and hydraulic design of Burnside Ridge Estates are in conformance with the requirements of the City of Meridian and the Ada County Highway District(ACHD) Policy Manual. Burnside Ridge Estates No.2 I Final Drainage Report .rune 25 1 193209000 2. FEIVIA FLOODPLAIN CLASSIFICATION The project lies within Zone "X" as shown on FIRM map number 16001CO250J, dated October 2, 2003. Zone "X" is defined by FEMA as: "Areas of 0.2% annual chance flood; areas of 1% annual chance flood with average depths of less than 1 foot or with drainage areas less than 1 square mile;and areas protected by levees from 1%annual chance flood." See Figure 2: FIRM Map in Appendix B. Burnside Ridge Estates No.2 I Final Drainage Report .rune 25 1 193209000 OFFSITE3. DR• • The site is protected from offsite flows generated from the south by the Calkins Lateral, and flows to the west, north and east are routed away from the site via existing roadway improvements from surrounding residential areas. Existing drainage patterns on Victory Road north of the property boundary and Linder Road east of the property boundary are maintained with the proposed pavement widening. Roadside borrow ditches have been designed in Burnside Ridge Estates No. 1 per ACHD Section 8200 Standard Detail 5 along the southern edge-of-pavement of Victory Road and western edge-of-pavement of Linder Road within the limits of the Site's frontage. The roadside ditches have been sized to provide the required storage for any flows generated offsite in the 100-year 1-hour storm event. Burnside Ridge Estates No.2 I Final Drainage Report .rune 25 1 193209000 4. HYDROLOGIC 4.1 REQUIRED STORAGE VOLUME 4.1.1. Methodology and Criteria As required by ACHD, the project will provide stormwater storage for the 100-year, 1-hour storm event. The required volume was determined using the Rational Equation below: Vr= Cw(P/12)A Where: V= Runoff Volume (ac-ft) Cw=Weighted Runoff coefficient (From ACHD Policy Manual Section 8000) P = 100-year, 1-hour rainfall depth (0.96 in) (From ACHD Policy Manual Section 8200) A= Drainage area Per Section 8000 of the ACHD Policy Manual, the 100-year runoff coefficient for Residential Single-Family is 0.50, the runoff coefficient for impervious areas is 0.95, and the runoff coefficient for landscape amenity areas with Type C soil is 0.11. See Table 1: Data Sheet and Table 2: Required Volume in Appendix A for the required storage volumes for this project. The total required volume for this project is 23,126 cubic- feet. Each infiltration facility is to drain 90% of the detained volume within 48 hours. A percolation rate of 4 in/hr was used per recommendations within the geotechnical report prepared by Materials Testing and Inspection, dated November 131", 2019, to determine the drainage time for each infiltration facility. 4.1.2. Common Lot Drainage Under existing conditions, the site has a historical outfall along the northern property line and drains via surface sheet flow. Accounting for the percolation rate of 4 in/hr and the reduced runoff coefficient for common lot areas,the ultimate runoff volume generated in the common lot area is not anticipated to exceed the existing condition and will be captured through soil absorption before inundating other drainage areas. Refer to Appendix A for Table 4: Provided Seepage Bed Volumes. See also Figure 3: Proposed Conditions in Appendix B for the delineation of specific drainage areas. 4.2 PROVIDED STORAGE VOLUME Subsurface storage facilities have been designed to provide the required 100-year, 1-hour storm event volumes of Basins 4, 8, and 9 per ACHD Policy Manual Section 8007.3. Pretreatment is provided with sand and grease traps. Refer to the ACHD BMP01- Sand and Appendix A for Table 8: Sand & Grease Traps for sand and grease trap sizing. The provided volumes of the seepage beds were calculated using the ACHD Stormwater Design Spreadsheet for BMP20-Seepage Beds. A roadside ditch has been designed to provide the required 100-year, 1-hour storm event volume for Basin 10 per ACHD Section 8200 Standard Detail 5. Basin 10 encompasses the southern half of E. Holstein Dr. and will sheet flow to a series of roadside ditches to contain all flow south of the centerline. These roadside ditches are designed to be temporary surface drainage facilities that will be removed when development south of E. Holstein Dr. is constructed. Refer to Appendix A for Table 3: Borrow Ditch Volumes. Burnside Ridge Estates No.2 I Final Drainage Report .rune 25 1 193209000 Sub-basins 5.3 and OS-2.1 each flow to storage facilities designed within Burnside Ridge Estates No. 1. These sub-basins contribute to existing infrastructure and have been previously included in the drainage report for Burnside Ridge Estates No. 1. The sub-basin areas are included in this report to display consistency between phases. The infrastructure has not been resized in this report. Refer to the ACHD BMP-20 Seepage Bed tables in Appendix A for seepage bed geometry, provided volume, required volume, and drain time. See also Figure 3: Proposed Conditions in Appendix B for the delineation of specific drainage areas. Burnside Ridge Estates No.2 I Final Drainage Report .rune 25 1 193209000 5. PROPOSED DRAINAGE INFASTRUCTURE 5.1 DRAINAGE CONVEYANCE SYSTEMS 5.1.1. Street Conveyance Runoff generated onsite from lots will typically sheet flow into the adjacent roadways where it will be conveyed towards proposed catch basins. Local streets are designed to convey the 25-year peak flow at or below the top of curb with a maximum water surface level 2-inches above the crown line, and the 100- year peak runoff is contained within the right of way. The local street cross section will consist primarily of 3-inch rolled curb. See Table 6: Street Capacities in Appendix A for street capacity calculations. 5.1.2. Storm Drain Conveyance Storm drains have been sized to convey the 25-year peak flow from the streets to the proposed seepage beds. Bentley FlowMaster was utilized to analyze the peak flows through the proposed storm drains. See Appendix A for the FlowMaster outputs and profiles. 5.1.3. Inlet Sizing Catch basins are used to capture runoff from local roadways. Inlet openings are sized using the Bentley FlowMaster software in compliance with the design criteria specified by ACHD. An inlet clogging factor of 50% will be used for all proposed grated inlets. See Table 7: Inlet Calculations in Appendix A for inlet sizing calculations. 5.2 FINISHED FLOOR ELEVATIONS AND OUTFALL REQUIREMENTS The following criteria was utilized to establish the lowest finished floor elevations for this development: • Finished Floors shall be a minimum of 18-inches above the highest adjacent low curb of the lot and above local outfall, whichever is greater. • All lots are to be graded to drain to the street at the front of each lot, unless otherwise noted. Burnside Ridge Estates No.2 I Final Drainage Report .rune 25 1 193209000 • SUMMARY AND • • The Burnside Ridge Estates No. 2 subdivision is designed to meet or exceed the drainage requirements set by the City of Meridian and the Ada County Highway District (ACHD) Policy Manual. Storage will be provided for the 100-year, 1-hour storm. Storage facilities will drain 90% of the storage volume within 48 hours via percolation. Finish floor elevations are designed to be a minimum of 18-inches above the highest adjacent low curb. Burnside Ridge Estates No.2 I Final Drainage Report .rune 25 1 193209000 7. REFERENCES August 2017. ACHD Section 8000 - Drainage and Stormwater Management, Ada County Highway District. August 2017. ACHD Section 8200 - Drainage and Stormwater Management, Ada County Highway District. June 2019. Meridian Idaho Public Works Department Design Standards—Section 7, City of Meridian. Burnside Ridge Estates No.2 I Final Drainage Report .rune 25 1 193209000 AppendixA — Tables and Calculations TABLE 1 DATA SHEET Sub-Basin ID Area Area 100 year Facility ID 4.1 35,954 0.83 0.50 4.2 85,070 1.95 0.50 Basin 4 Total 121,024 2.78 0.50 Seepage Bed 4 5.1 31,511 0.72 0.50 5.2 6,647 0.15 0.50 5.3 134,175 3.08 0.50 Basin 5 Total 172,333 3.96 0.50 Seepage Bed 5(Phase 1) Basin 8 Total 225,831 5.18 0.50 Seepage Bed 8 9.1 44,305 1.02 0.50 9.2 4,135 0.09 0.95 Basin 9 Total 48,440 1.11 0.54 Seepage Bed 9 10.1 690 0.02 0.95 10.2 722 0.02 0.95 10.3 1,160 0.03 0.95 10.4 1,199 0.03 0.95 10.5 2,340 0.05 0.95 Basin 10 Total 6,111 0.14 0.95 Borrow Ditch 3 OS-2.1 14,600 0.34 0.50 OS-2.2 5,770 0.13 0.50 OS-2.3 9,255 0.21 0.50 OS-2.4 13,045 0.30 0.50 OS-2.5 19,432 0.45 0.50 OS-2.6 25,290 0.58 0.50 OS-2.7 6,202 0.14 0.50 Basin OS-2 Total 88,649 2.04 0.50 Borrow Ditch 2 (Phase 1) Total (Site): 10.02 C Factors obtained from ACHD Policy Manual Section 8000. TABLE 2 REQUIRED VOLUME 100-year, 1-hour Precipitation = 0.96 inches 00 Year Volume Major Basin ID Drainage Area (ac) Runoff Required Basin 4.1 0.83 0.50 1,426.28 4.2 1.95 0.50 3,374.69 Basin 4 Total 2.78 0.50 4,800.97 Seepage Bed 4 5.1 0.72 0.50 1,250.02 5.2 0.15 0.50 263.67 5.3 3.08 0.50 5,322.65 Basin 5 Total 3.96 0.50 6,836.34 Seepage Bed 5 (Phase 1) Basin 8 Total 5.18 0.50 8,958.60 Seepage Bed 8 9.1 1.02 0.50 1,757.55 9.2 0.09 0.95 311.66 Basin 9 Total 1.11 0.54 2,069.22 Seepage Bed 9 10.1 0.02 0.95 51.97 10.2 0.02 0.95 54.41 10.3 0.03 0.95 87.44 10.4 0.03 0.95 90.38 10.5 0.05 0.95 176.40 Basin 10 Total 0.14 0.95 460.61 Borrow Ditch 3 OS-2.1 0.34 0.50 579.17 OS-2.2 0.13 0.50 228.89 OS-2.3 0.21 0.50 367.14 OS-2.4 0.30 0.50 517.49 OS-2.5 0.45 0.50 770.86 OS-2.6 0.58 0.50 1,003.24 OS-2.7 0.14 0.50 246.03 Basin OS-2 Total 2.04 0.50 3,516.65 Borrow Ditch 2 (Phase 1) Total(Site): 23,125.73 Note: Intensity obtained from ACHD Storm Water Design Methods and Calculations TABLE 3 BORROW DITCH VOLUMES Total 10OYearVolume Excess Required Disposal Borrow Ditch or Elevation Total Area Reducting Volume Drains •i Basin ID Pond ID (ft) (ft) Factor* Provided Required Volume Drain Time Rate Drain 48 hrs Basin 10 Total Borrow Ditch 3 1.00 2,307.18 0.50 702.95 460.61 242.34 48 4.0 5.48 YES 0.00 504.62 TOTAL 460.61 242.34 Note:Refer to the ACHD Standard Drawing Detail 05 for Borrow Ditch sloping and material requirements. *Borrow ditches match street longitudinal slope. Check dams are provided such that storage depth does not exceed 1-ft between check dams, l.e., depth at upstream end is 0-ft while depth at downstream end is 1-ft.Accordingly the average end-area volume is reduced by 0.5 to account for the sloped facility. TABLE 4 PROVIDED SEEPAGE BED VOLUMES Total Seepage Bed Length In Volume Percolation Time to Drains Basin ID ID Depth (ft) Width (ft) Per ACHD Common Required . . Ratio Rate Drain 90% in 48 Basin 4 SP-4 10.0 20.0 55.0 Y 4,800.97 0.40 4.00 11.78 Yes Basin 8 SP-8 10.0 20.0 90.0 Y 8,958.60 0.40 4.00 13.44 Yes Basin 9 SP-9 10.0 10.0 65.0 Y 2,069.22 0.40 4.00 9.98 Yes TOTAL 15828.78 Note: ACHD Seepage Bed Calculations print outs for each seepage bed are included in Appendix A. This summary table provided for convenience only. TABLE 5 TIME OF CONCENTRATION CALCULATIONS Drainage Area Sheet Flow Time of Concentration Gutter Flow Time of Concentration(Tgutter) Pipe Travel Time Total Time of n L(ft) 1(in/hr)* s TS L(ft) k s Vgutter (ft/s) Tgutter (min) L(ft) V(ft/s)** Tpipe T� Basin 4 Total 0.24 235.1 1 0.001 83.34 377.8 20.3 0.015 2.49 2.53 46.5 3.21 0.24 86.1 Basin 8 Total 0.24 234 1 0.001 83.11 506 20.3 0.01 2.03 4.15 81.4 3.21 0.42 87.7 Basin 9 Total 0.24 131.4 1 0.02 23.93 300.5 20.3 0.011 2.13 2.35 17 3.21 0.09 26.4 Basin 10 Total 0.24 28 1 0.02 9.47 0 20.3 0.005 1.44 0.00 0 3.21 0.00 10.0 *A value of 1%hr was assumed for the intensity in Time of Concentration calculations **A velocity of 3.21 was calculated for a 12"dia.pipe running at a 0.5%slope. TABLE 6 STREET FLOW CALCULATIONS 25 Year 100 Year Initial Water- 3"Curb 6"Curb 6"Street 25-year 100-year Is 100 Year Approx.area Is 100-year Sub-Basin ID Drainage Drainage Rainfall Rainfall 00 Year Flow Tc Street course Street Street Street 3"Street 6"Street Capacity(6 Peak Peak runoff not contained runoff (Street Basins Only)6 Area Area Intensity Intensity Runoff Coeff. Time (min)3 Slope Length Class. Velocity Velocity Capacity Capacity max above Runoff Runoff contained within 3"curb contained (ft2) (ac) (C)2 )3 N (cfs)4 (cfs)4 curb within within 3" )7 contained Basin 4 Total 121,024 2.78 0.69 0.96 0.50 10.00 86.12 1.50% 378 Local 3.85 6.68 18.80 76.32 122.14 0.96 1.33 Yes N/A Yes Basin 8 Total 225,831 5.18 0.69 0.96 0.50 10.00 87.69 1.00% 506 Local 3.15 5.45 15.35 62.31 99.73 1.79 2.49 Yes N/A Yes Basin 9 Total 48,440 1.11 1.14 1.57 0.54 10.00 26.37 1.10% 301 Local 3.30 5.72 16.10 65.35 104.60 0.68 0.94 Yes N/A Yes Basin 10 Total 6,111 0.14 1.85 2.58 0.95 10.00 10.00 0.50% 0 Local 2.23 3.85 10.85 44.06 70.52 0.25 0.34 Yes N/A Yes Total(Site): 3.43 4.76 3 For Subasins, Initial Flow Time equals 10 minutes 5 Peak Runoff=(1)x(3)x Area=CiA 6 Refer to the Proposed Drainage Conditions Exhibit for Sub-Basin Areas. 7 Value(as applicable)is calculated by multiplying the respective Area by the ratio of the difference between the 3"Street Capacity and the 100 Year Peak Runoff to the 100 Year Peak Runoff TABLE 7 INLET CALCULATIONS 0i100- Required Inlet Label (Drainage Area) Inlet Detail Discharge Discharge Efficiency year Flow year Flow Lengthl Condition Notes 25-Year Catch Basin CB-4.1A&B (Area 4) ISPWC SD-604A Type IV 0.96 1.33 0.96 1.33 0.6 Sump Single inlet provided at this sump location. 25-Year Catch Basin CB-8.1A&B (Area 8) ISPWC SD-604A Type IV 1.79 2.49 1.79 2.49 2.1 Sump Single inlet provided at this sump location. 25-Year Catch Basin CB-9.1A&B (Area 9) ISPWC SD-604A Type IV 0.68 0.94 0.68 0.94 0.4 Sump Single inlet provided at this sump location. Total (Site): 3.43 4.76 1. Assuming 2-foot gutter width, 5% gutter cross-slope, 2% road cross-slope, 16-foot spread, 0.5-foot depth, 0-inch local depression, 2-foot local depression width, and 88 degree throat incline angle. Table 8 Sand & Grease Traps Number Baff le Velocity Is Vault Size of S&G Peak Spac ng Throat Area (ft2) (0.5 fps Velocity Basin ID Flow Width (in) Complian 1000 G 1 0.96 20 48 6.67 0.14 Basin 4 Total 1000 G 1 1.79 20 48 6.67 0.27 Basin 8 Total 1000 G 1 0.68 20 48 6.67 0.10 rk Basin 9 Total Reference for Throat Widths (in) Boise Lar-ken ADS WQU, Vault BMP 16 1000 G 48 50.5 n/a 1500 G 60 61.5 n/a WQU1000 n/a n/a 60 WQU1500 n/a n/a 60 ACHD Calculation Sheet for Finding Peak Discharge/Volume-Rational Method NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. arge Rate�ational M�!Slated for Calculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Burnside Ridge Estates No.2 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm(100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities(25 max) 4 Click to Show More Subbasins ❑ Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 6 7 8 9 10 S Area of Drainage Subbasin(SF or Acres) SF 35,954 85,070 Acres 2.78 6 Determine the Weighted Runoff Coefficient(C) 0.50 0.50 C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.50 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User Calculate to Min. Estimated Runoff Coefficients for Various Surface min - Type of Surface Runoff Coefficients"( 8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 2.58 in hr Business Downtown areas 0.70-0.95 9 Calculate the Post-Development peak discharge(QPeak) Qpe.k 3.58 cfs Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 10 Calculate total runoff vol(V)(for sizing primary storage) V 4,801 ft3 Multi-family 0.60-0.75 V=CI(Tc=60)Ax3600 Residential(rural) 0.25-0.40 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70 Industrial and Commercial Enter Percentile Storm I(95th percentile=0.60 in) 95th 0.60 in Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) Vrr 3,001 W Heavy areas 0.90 Parks,Cemeteries 0.10-0.25 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) cfs Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 13 Volume Summary Unimproved areas 0.10-0.30 Surface Storage:Basin Streets Asphalt 0.95 Basin Forebay V 480 ft' Concrete 0.95 Primary Treatment/StorageBasin V 4,321 ft' Brick 0.95 Subsurface Storage Roofs 0.95 Gravel 0.75 Volume Without Sediment Factor(See BMP 20 Tab) V 4,801 ft' Fields:Sandy soil soil Type Slope A B C D Flat:0-2% 0.04 0.07 0.11 0. Average:2-6% 0.09 0.12 0.15 0. Steep:>6% 0.13 0.13 0.23 0. Adapted from ASCE K:\BOI_Civil\193209000 Burnside Ridge Estates\_Project Files\Engineering\Drainage\Phase 2\Spreadsheets\Phase 2-ACHD Calcs.xlsm 6/19/2025,11:22 AM Version 10.5,November 2018 ACHD Calculation Sheet for Finding Peak Discharge/Volume-Rational Method NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. arge Rate�ational M�!Slated for Calculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Burnside Ridge Estates No.2,Facility 3 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm(100-Year or 25-Year With 100-Year Flood Route) 100 Click to Show More Subbasins ❑ Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 6 7 8 9 10 5 Area of Drainage Subbasin(SF or Acres) SF 225,831 Acres 5.18 6 Determine the Weighted Runoff Coefficient(C) 0.50 C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg1 0.50 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User calculate min 10 Min. Estimated Runoff Coefficients for Various Surface - Type of Surface Runoff Coefficients"( 8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 2.58 in/hr Business Downtown areas 0.70-0.95 y Calculate the Post-Development peak discharge(QPeak) Qpe.k 6.69 cfs Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 10 Calculate total runoff vol(V)(far sizing primary storage) V 8,959 ft Multi-family 0.60-0.75 V=CI(Tc=60)Ax3600 Residential(rural) 0.25-0.40 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70 Industrial and Commercial Enter Percentile Storm I(95th percentile=0.60 in) 95th 0.60 in Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) V„ 5,599 ft' Heavy areas 0.90 Parks,Cemeteries 0.10-0.25 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) cfs Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 13 Volume Summary Unimproved areas 0.10-0.30 Surface Storage:Basin Streets Asphalt 0.95 Basin Forebay V 896 ft' Concrete 0.95 Primary Treatment/StorageBasin V 8,063 ft' Brick 0.95 Subsurface Storage Roofs 0.95 Gravel 0.75 Volume Without Sediment Factor(See BMP 20 Tab) V 8,959 ft' Fields:Sandy soil Soil Type Slope A B C D Flat:0-2% 0.04 0.07 0.11 0. Average:2-6% 0.09 0.12 0.15 0. Steep:>6% 0.13 0.18 0.23 0. Adapted from ASCE K:\BOI_Civil\193209000 Burnside Ridge Estates\_Project Files\Engineering\Drainage\Phase 2\Spreadsheets\Phase 2-ACHD Calcs.xlsm 6/19/2025,11:22 AM Version 10.5,November 2018 ACHD Calculation Sheet for Finding Peak Discharge/Volume-Rational Method NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. arge Rate�ational M�!Slated for Calculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Burnside Ridge Estates No.2,Facility 4 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm(100-Year or 25-Year With 100-Year Flood Route) 100 Click to Show More Subbasins ❑ Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 6 7 8 9 10 5 Area of Drainage Subbasin(SF or Acres) SF 44,305 4,135 Acres 1.11 6 Determine the Weighted Runoff Coefficient(C) 0.50 0.95 C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg1 0.54 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User Calculate min 10 Min. Estimated Runoff Coefficients for Various Surface - Type of Surface Runoff Coefficients"( 8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 2.58 in/hr Business Downtown areas 0.70-0.95 y Calculate the Post-Development peak discharge(QPeak) Qpe.k 1.54 cfs Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 10 Calculate total runoff vol(V)(far sizing primary storage) V 2,069 ft Multi-family 0.60-0.75 V=CI(Tc=60)Ax3600 Residential(rural) 0.25-0.40 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70 Industrial and Commercial Enter Percentile Storm I(95th percentile=0.60 in) 95th 0.60 in Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) V,r 1,293 ft' Heavy areas 0.90 Parks,Cemeteries 0.10-0.25 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) cfs Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 13 Volume Summary Unimproved areas 0.10-0.30 Surface Storage:Basin Streets Asphalt 0.95 Basin Forebay V 207 ft' Concrete 0.95 Primary Treatment/StorageBasin V 1,862 ft' Brick 0.95 Subsurface Storage Roofs 0.95 Gravel 0.75 Volume Without Sediment Factor(See BMP 20 Tab) V 2,069 ft' Fields:Sandy soil Soil Type Slope A B C D Flat:0-2% 0.04 0.07 0.11 0. Average:2-6% 0.09 0.12 0.15 0. Steep:>6% 0.13 0.18 0.23 0. Adapted from ASCE K:\BOI_Civil\193209000 Burnside Ridge Estates\_Project Files\Engineering\Drainage\Phase 2\Spreadsheets\Phase 2-ACHD Calcs.xlsm 6/19/2025,11:22 AM Version 10.5,November 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the"Peak QV"tab Calculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Burnside Ridge Estates No.2 2 Enter number of Seepage Beds(25 max) 4 3 Design Storm 100 4 Weighted Runoff Coefficient C 0.50 Link to: LQV _ QV2 5 Area A(Acres) 2.78 acres QV3 6 Approved discharge rate(if applicable) 0.00 cfs QV4 QV TR55 _ 7 Is Seepage Bed in Common Lot? Yes V 4,801 ft3 0%Sediment 8 Set Total Design Width of All Drain Rock W 20.0 ft 9 Set Total Design Depth of All Drain Rock D 10.0 ft Rock Only,Do Not Include Filter Sand Depth or Cover 10 Void Ratio of Drain Rock Voids 0.4 0.4 for 1.5"-2"drain rock and 3/4"Chips 11 Design Infiltration Rate(8 in/hr max) Perc 4.00 in/hr 12 Size of WC.Perf Pipe(Pert 180°) Dia pipe 18 in 13 Size of Overflow Perf Pipe(Perfs 360°),REQD if Q100>3.3 cfs 12 in 14 Calculate Total Storage per Foot Spf 87.3 Oft 15 Calculate Design Length L 0 55 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 55 ft 17 Variable Infiltration Window W SWW 20.0 ft 18 Time to Drain 11.8 hours 90%volume in 48-hours minimum 19 Length of WQ&Overflow Perf Pipes 55 ft 20 Perf Pipe Checks.Qperf>=Qpeak; where Qperf=CdxAxy(2xgxH) Optional Storage Chambers Note:This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume,Without Rock,Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume,With Rock,Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ft2 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum K:\B01_Civil\193209000 Burnside Ridge Estates\_Project Files\Engineering\Drainage\Phase 2\Spreadsheets\Phase 2—ACHD Calcs.xlsm 6/19/2025,11:22 AM Version 10.0,May 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the"Peak QV"tab Calculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Burnside Ridge Estates No.2,Facility 3,Bed 3 2 Enter number of Seepage Beds(25 max) 4 3 Design Storm 100 4 Weighted Runoff Coefficient C 0.50 Link to: QV QV2 5 Area A(Acres) 5.18 acres [QV3� 6 Approved discharge rate(if applicable) 0.00 cfs QV4 QV TR55 _ 7 Is Seepage Bed in Common Lot? Yes V 8,959 ft3 0%Sediment 8 Set Total Design Width of All Drain Rock W 20.0 ft 9 Set Total Design Depth of All Drain Rock D 10.0 ft Rock Only,Do Not Include Filter Sand Depth or Cover 10 Void Ratio of Drain Rock Voids 0.4 0.4 for 1.5"-2"drain rock and 3/4"Chips 11 Design Infiltration Rate(8 in/hr max) Perc 4.00 in/hr 12 Size of WC.Perf Pipe(Pert 180°) Dia pipe 18 in 13 Size of Overflow Perf Pipe(Perfs 360°),REQD if Q100>3.3 cfs 12 in 14 Calculate Total Storage per Foot Spf 87.3 Oft 15 Calculate Design Length L 0 90 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 90 ft 17 Variable Infiltration Window W SWW 20.0 ft 18 Time to Drain 13.4 hours 90%volume in 48-hours minimum 19 Length of WQ&Overflow Perf Pipes 90 80 ft 20 Perf Pipe Checks.Qperf>=Qpeak; where Qperf=CdxAxy(2xgxH) Optional Storage Chambers Note:This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume,Without Rock,Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume,With Rock,Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ft2 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum K:\B01_Civil\193209000 Burnside Ridge Estates\_Project Files\Engineering\Drainage\Phase 2\Spreadsheets\Phase 2—ACHD Calcs.xlsm 6/19/2025,11:22 AM Version 10.0,May 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Note this spreadsheet pulls information from the"Peak QV"tab Calculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Burnside Ridge Estates No.2,Facility 4,Bed 4 2 Enter number of Seepage Beds(25 max) 4 3 Design Storm 100 4 Weighted Runoff Coefficient C 0.50 Link to: QV J QV2 5 Area A(Acres) 1.11 acres QV3 6 Approved discharge rate(if applicable) 0.00 cfs (Q V4� QV TR55 _ 7 Is Seepage Bed in Common Lot? No V 2,402 ft3 25%Sediment 8 Set Total Design Width of All Drain Rock W 10.0 ft 9 Set Total Design Depth of All Drain Rock D 10.0 ft Rock Only,Do Not Include Filter Sand Depth or Cover 10 Void Ratio of Drain Rock Voids 0.4 0.4 for 1.5"-2"drain rock and 3/4"Chips 11 Design Infiltration Rate(8 in/hr max) Perc 4.00 in/hr 12 Size of WC.Perf Pipe(Pert 180°) Dia pipe 18 in 13 Size of Overflow Perf Pipe(Perfs 360°),REQD if Q100>3.3 cfs in 14 Calculate Total Storage per Foot Spf 43.5 ft3/ft 15 Calculate Design Length L 0 65 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 65 ft 17 Variable Infiltration Window W SWW 10.0 ft 18 Time to Drain 10.0 hours 90%volume in 48-hours minimum 19 Length of WQ&Overflow Perf Pipes 65 ft 20 Perf Pipe Checks.Qperf>=Qpeak; where Qperf=CdxAxy(2xgxH) Optional Storage Chambers Note:This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume,Without Rock,Per Manuf 45.90 ft3/Unit 6 Chamber Storage Volume,With Rock,Per Manuf 74.90 ft3/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ft2 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum K:\B01_Civil\193209000 Burnside Ridge Estates\_Project Files\Engineering\Drainage\Phase 2\Spreadsheets\Phase 2—ACHD Calcs.xlsm 6/19/2025,11:22 AM Version 10.0,May 2018 Worksheet for 12in Capacity (Max Slope) Project Description Friction Method Manning Formula Solve For Full Flow Capacity Input Data Roughness Coefficient 0.010 Channel Slope 5.000 % Normal Depth 12.0 in Diameter 12.0 in Discharge 10.36 cfs Results Discharge 10.36 cfs Normal Depth 12.0 in Flow Area 0.8 ftz Wetted Perimeter 3.1 ft Hydraulic Radius 3.0 in Top Width 0.00 ft Critical Depth 11.9 in Percent Full 100.0 % Critical Slope 4.703 % Velocity 13.19 ft/s Velocity Head 2.70 ft Specific Energy 3.70 ft Froude Number (N/A) Maximum Discharge 11.14 cfs Discharge Full 10.36 cfs Slope Full 5.000 % Flow Type Undefined GVF Input Data Downstream Depth 0.0 in Length 0.0 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.0 in Profile Description N/A Profile Headloss 0.00 ft Average End Depth Over Rise 0.0 % Normal Depth Over Rise 100.0 % Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 12.0 in Critical Depth 11.9 in Channel Slope 5.000 % Critical Slope 4.703 % Bentley Systems,Inc. Haestad Methods Solution FlowMaster BRIE No 2.fm8 Center [10.03.00.03] 6/19/2025 27 Siemon Company Drive Suite 200 W Page 1 of 1 Watertown,CT 06795 USA +1-203-755-1666 Worksheet for 12in Capacity (Min Slope) Project Description Friction Method Manning Formula Solve For Full Flow Capacity Input Data Roughness Coefficient 0.010 Channel Slope 0.200 % Normal Depth 12.0 in Diameter 12.0 in Discharge 2.07 cfs Results Discharge 2.07 cfs Normal Depth 12.0 in Flow Area 0.8 ftz Wetted Perimeter 3.1 ft Hydraulic Radius 3.0 in Top Width 0.00 ft Critical Depth 7.4 in Percent Full 100.0 % Critical Slope 0.412 % Velocity 2.64 ft/s Velocity Head 0.11 ft Specific Energy 1.11 ft Froude Number (N/A) Maximum Discharge 2.23 cfs Discharge Full 2.07 cfs Slope Full 0.200 % Flow Type Undefined GVF Input Data Downstream Depth 0.0 in Length 0.0 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.0 in Profile Description N/A Profile Headloss 0.00 ft Average End Depth Over Rise 0.0 % Normal Depth Over Rise 0.0 % Downstream Velocity 0.00 ft/s Upstream Velocity 0.00 ft/s Normal Depth 12.0 in Critical Depth 7.4 in Channel Slope 0.200 % Critical Slope 0.412 % Bentley Systems,Inc. Haestad Methods Solution FlowMaster BRIE No 2.fm8 Center [10.03.00.03] 6/19/2025 27 Siemon Company Drive Suite 200 W Page 1 of 1 Watertown,CT 06795 USA +1-203-755-1666 Worksheet for 18in Capacity (Max Slope) Project Description Friction Method Manning Formula Solve For Full Flow Capacity Input Data Roughness Coefficient 0.010 Channel Slope 5.000 % Normal Depth 18.0 in Diameter 18.0 in Discharge 30.53 cfs Results Discharge 30.53 cfs Normal Depth 18.0 in Flow Area 1.8 ftz Wetted Perimeter 4.7 ft Hydraulic Radius 4.5 in Top Width 0.00 ft Critical Depth 17.9 in Percent Full 100.0 % Critical Slope 4.738 % Velocity 17.28 ft/s Velocity Head 4.64 ft Specific Energy 6.14 ft Froude Number (N/A) Maximum Discharge 32.84 cfs Discharge Full 30.53 cfs Slope Full 5.000 % Flow Type Undefined GVF Input Data Downstream Depth 0.0 in Length 0.0 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.0 in Profile Description N/A Profile Headloss 0.00 ft Average End Depth Over Rise 0.0 % Normal Depth Over Rise 100.0 % Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 18.0 in Critical Depth 17.9 in Channel Slope 5.000 % Critical Slope 4.738% Bentley Systems,Inc. Haestad Methods Solution FlowMaster BRIE No 2.fm8 Center [10.03.00.03] 6/19/2025 27 Siemon Company Drive Suite 200 W Page 1 of 1 Watertown,CT 06795 USA +1-203-755-1666 Worksheet for 18in Capacity (Min Slope) Project Description Friction Method Manning Formula Solve For Full Flow Capacity Input Data Roughness Coefficient 0.010 Channel Slope 0.200 % Normal Depth 18.0 in Diameter 18.0 in Discharge 6.11 cfs Results Discharge 6.11 cfs Normal Depth 18.0 in Flow Area 1.8 ftz Wetted Perimeter 4.7 ft Hydraulic Radius 4.5 in Top Width 0.00 ft Critical Depth 11.5 in Percent Full 100.0 % Critical Slope 0.371 % Velocity 3.46 ft/s Velocity Head 0.19 ft Specific Energy 1.69 ft Froude Number (N/A) Maximum Discharge 6.57 cfs Discharge Full 6.11 cfs Slope Full 0.200 % Flow Type Undefined GVF Input Data Downstream Depth 0.0 in Length 0.0 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.0 in Profile Description N/A Profile Headloss 0.00 ft Average End Depth Over Rise 0.0 % Normal Depth Over Rise 100.0 % Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 18.0 in Critical Depth 11.5 in Channel Slope 0.200 % Critical Slope 0.371 % Bentley Systems,Inc. Haestad Methods Solution FlowMaster BRIE No 2.fm8 Center [10.03.00.03] 6/19/2025 27 Siemon Company Drive Suite 200 W Page 1 of 1 Watertown,CT 06795 USA +1-203-755-1666 Worksheet for Local Rd - 3" Rolled Curb Project Description Friction Method Manning Formula Solve For Discharge Input Data Channel Slope 0.400 % Normal Depth 3.2 in Section Definitions Station Elevation (ft) (ft) 0+00 0.30 0+01 0.00 0+02 0.10 0+17 0.40 0+31 0.10 0+32 0.00 0+33 0.30 Roughness Segment Definitions Start Station Ending Station Roughness Coefficient (0+00,0.30) (0+33,0.30) 0.013 Options Current Roughness Weighted Pavlovskii's Method Method Open Channel Weighting Pavlovskii's Method Method Closed Channel Weighting Pavlovskii's Method Method Results Discharge 3.29 cfs Roughness Coefficient 0.013 Elevation Range 0.0 to 0.4 ft Flow Area 2.1 ftz Wetted Perimeter 20.3 ft Hydraulic Radius 1.2 in Top Width 20.23 ft Normal Depth 3.2 in Critical Depth 3.1 in Critical Slope 0.538 % Velocity 1.58 ft/s Velocity Head 0.04 ft Specific Energy 0.31 ft Froude Number 0.870 Flow Type Subcritical Bentley Systems,Inc. Haestad Methods Solution FlowMaster BRIE No 2.fm8 Center [10.03.00.03] 6/19/2025 27 Siemon Company Drive Suite 200 W Page 1 of 3 Watertown,CT 06795 USA +1-203-755-1666 Worksheet for Local Rd - 3" Rolled Curb GVF Input Data Downstream Depth 0.0 in Length 0.0 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.0 in Profile Description N/A Profile Headloss 0.00 ft Downstream Velocity 0.00 ft/s Upstream Velocity 0.00 ft/s Normal Depth 3.2 in Critical Depth 3.1 in Channel Slope 0.400 % Critical Slope 0.538% Bentley Systems,Inc. Haestad Methods Solution FlowMaster BRIE No 2.fm8 Center [10.03.00.03] 6/19/2025 27 Siemon Company Drive Suite 200 W Page 2 of 3 Watertown,CT 06795 USA +1-203-755-1666 Worksheet for CB-4.1A&B (Sag) Project Description Solve For Grate Length Input Data Discharge 0.96 cfs Spread 16.0 ft Gutter Width 1.50 ft Gutter Cross Slope 5.400 % Road Cross Slope 2.000 % Grate Width 1.36 ft Local Depression 0.0 in Local Depression Width 0.0 in P-50 mm x Grate Type 100 mm(P-1- 7/8"-4") Clogging 50.0% Results Grate Length 0.6 ft Depth 4.5 in Gutter Depression 0.6 in Total Depression 0.6 in Open Grate Area 0.3 ftz Active Grate Weir Length 1.9 ft Bentley Systems,Inc. Haestad Methods Solution FlowMaster BRIE No 2.fm8 Center [10.03.00.03] 6/19/2025 27 Siemon Company Drive Suite 200 W Page 1 of 1 Watertown,CT 06795 USA +1-203-755-1666 Worksheet for CB-MA&B (Sag) Project Description Solve For Grate Length Input Data Discharge 1.79 cfs Spread 16.0 ft Gutter Width 1.50 ft Gutter Cross Slope 5.400 % Road Cross Slope 2.000 % Grate Width 1.36 ft Local Depression 0.0 in Local Depression Width 0.0 in P-50 mm x Grate Type 100 mm(P-1- 7/8"-4") Clogging 50.0% Results Grate Length 2.1 ft Depth 4.5 in Gutter Depression 0.6 in Total Depression 0.6 in Open Grate Area 1.1 ftz Active Grate Weir Length 3.4 ft Bentley Systems,Inc. Haestad Methods Solution FlowMaster BRIE No 2.fm8 Center [10.03.00.03] 6/19/2025 27 Siemon Company Drive Suite 200 W Page 1 of 1 Watertown,CT 06795 USA +1-203-755-1666 Worksheet for CB-9.1A&B (Sag) Project Description Solve For Grate Length Input Data Discharge 0.68 cfs Spread 16.0 ft Gutter Width 1.50 ft Gutter Cross Slope 5.400 % Road Cross Slope 2.000 % Grate Width 1.36 ft Local Depression 0.0 in Local Depression Width 0.0 in P-50 mm x Grate Type 100 mm(P-1- 7/8"-4") Clogging 50.0% Results Grate Length 0.4 ft Depth 4.5 in Gutter Depression 0.6 in Total Depression 0.6 in Open Grate Area 0.2 ftz Active Grate Weir Length 1.8 ft Bentley Systems,Inc. Haestad Methods Solution FlowMaster BRIE No 2.fm8 Center [10.03.00.03] 6/19/2025 27 Siemon Company Drive Suite 200 W Page 1 of 1 Watertown,CT 06795 USA +1-203-755-1666 Appendix B — Figures i 1 �I L x pi b, IC fi _ -- �a —T 3 ..,;c, , is -Gu t 11 1 i y, s 1 BURNSIDE RIDGE ESTATES NO.2 VICINITY MAP NORTH June 23, 2025 National Flood Hazard Layer FI RMette FEMA Legend 116°25'26"W 439430"N SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT • W J, + Without Base Flood Elevation(BFE) + _ Zone A,V,A99 I ` SPECIAL FLOOD With BFE or Depth zone AE,AO,AH,VE,AR HAZARD AREAS Regulatory Floodway s /o 0.2 Annual Chance Flood Hazard,Areas s o of 1%annual chance flood with average d depth less than one foot or with drainage areas of less than one square mile zone x _ Future Conditions 1%Annual+ Chance Flood Hazard Zone x Area with Reduced Flood Risk due to j OTHER AREAS OF Levee.See Notes.zone FLOOD HAZARD Area with Flood Risk due to Leveezone o NO SCREEN Area of Minimal Flood Hazard zonex i Q Effective LOMRs OTHER AREAS Area of Undetermined Flood Hazard zone y • s. GENERAL ----- Channel,Culvert,or Storm Sewer STRUCTURES IIIIIII Levee,Dike,or Floodwall V Cross Sections with 1%Annual Chance 17•5 Water Surface Elevation Cc.7oxxnt , AREA F MINIMA RD s- - - Coastal Transect Z 1[ —513— Base Flood Elevation Line(BFE) 1I}1 Limit of Study Jurisdiction Boundary —--- Coastal Transect Baseline OTHER _ Profile Baseline FEATURES Hydrographic Feature Digital Data Available N No Digital Data Available MAP PANELS Unmapped QThe pin displayed on the map is an approximate point selected by the user and does not represent an authoritative property location. 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 basemap accuracy standards The flood hazard information is derived directly from the authoritative NFHL web services provided by FEMA.This map was exported on 1/2/2025 at 11:48 PM and does not { I reflect changes or amendments subsequent to this date and time.The NFHL and effective information may change or become 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, 116024'48"W 43°34'4"N FIRM panel number,and FIRM effective date.Map images for Feet 1:6 000 unmapped and unmodernized areas cannot be used for 0 250 500 1,000 1,500 2,000 regulatory purposes. Basemap Imagery Source:USGS National Map 2023 W. VICTORY ROAD -- - - - - - - _ - - : - - - BORROW DITCH VOLUMES 7", Total 100 Year BorrowTotal Excess Required Disposal Time toElevation Reducing Volume Volume Drains 90% Basin ID Ditch or (ft) Area Factor* Provided Required Volume Drain Time Rate Drain in 48 hrs Pond ID (ft2) (ft3) (ft3) (ft3) (hrs) (in/hr) (hrs) I \ r I I I I I 1 .00 2,307.18 Basin 10 Borrow Total Ditch 3 0.50 702.95 460.61 242.34 48 4.0 5.48 YES 0.00 504.62 _ II z IIII I I I II I ti \ �I sr -\ III IIII II \- �Iljl�I I I I I TOTAL 460.61 242.34 III BURNSIDE RIDGE I Note: Refer to the ACHD Standard Drawing Detail 05 for Borrow Ditch sloping and material requirements. � N ESTATES NO. 6 I I I I 9 p� 9' q l I\ (FUTURE PHASE) I I ° I`�\ \ I *Borrow ditches match street longitudinal slope. Check dams are provided such that storage depth does not exceed 1-ft between check dams, I.e., depth at upstream end is 0-ft while depth at downstream end is 1-ft. Accordingly the average end-area volume is reduced by 0.5 to account for the sloped facility. Q ❑ � I \ \ PROVIDED SEEPAGE BED VOLUMES Length In Total Volume Percolation Time to Drains Seepage Void Basin ID Depth (ft) Width (ft) Per Common Required Rate Drain 90% in 48 i■■■I ACHD ft Lot (ft3 in/hr hrs hrs Bed ID Ratio III_^ _ ��l ^I i IIII I \ \ I I II 111�`I ) I I �11 / III cJ� //1 \I I �L�� \\ \\ I I \ I I I \ \ \ I I Seepage Bed SP-4 10.0 20.0 55.0 Y 4,800.97 0.40 4.00 11.78 Yes 4 Seepage Bed SP-8 10.0 20.0 90.0 Y 8,958.60 0.40 4.00 13.44 Yes ^ Seepage Bed w SP-9 10.0 10.0 65.0 Y 2,069.22 0.40 4.00 9.98 Yes Q \ 9 LO 00 Note: ACHD Seepage Bed Calculations print outs for each seepage bed are included in Appendix A. This summary table provided for 00 Qo 0 II \ \ \ I I convenience only. 04 ° 0CD co N M W O J. II\ - I \ \ < I \ BURNSIDE RIDGE \\ \\ E. GUERNSEY ST. m ` \� � \ \ ESTATES \ \ \ / \ \ \ \ \ /\��J O O (FUTURE PHASE) \ \ \\ I \ v / I� m IJL\ \\ \\ \ �FP \ �\ \ \ \\ r \ \ \ \ / I CV Q � _ LEGEND O \ \ I \ \ \\ \ \ \ \ y l BASIN DRAINAGE AREA w Z �\ E. PIVOT ROAD- _ BURNSIDE RIDGE \ -I \ / �I CONTRIBUTING AREA FROM OTHER PHASE Q ESTATES NO. 1 I / \ SUB BASIN FLOW PATH NORTH Z \ \ \ \ \ (EXISTING PHASE) \ co Q LU N \ \ \ \\ \ \ 1 \ \ \ \ \\ \ \ ` Q 1 \ II 0.5 0.5 CB-4.1A \ I I P` A: RUNOFF COEFFICIENT W O - \ \ \ \ \ \ BURNSIDE RIDGE \ ` - �-� \y\\ \ II I g \ \ \ \ ESTATES NO. 5 - \\\ '�\\ 4.1 4.2 Q25: 0.48 CFS y \I B: BASIN ID (� \ \\ \ \ C (FUTURE PHASE) \ \1 I �� \\\ \ \ \ � 0.83 I C: BASIN AREA (AC) � W � 1.95 Q100: 0.67 CFS III \\\ \\ \ \ \ \ \ \ \ \ \ \ \ X \ 12% - CB-4.1B BURNSIDE RIDGE LU W 0 W. DRAWBAR ST. IIM LEGEND GRAPHIC AL IN \ \ \ \ \ \ „�\ �\ \ _ Q25: 0.48 CFS ESTATES NO. 7 - (n \ \ \ \ \ \ \ \ \ \ e \\ \ �< \ Q100: 0.67 CFS FUTURE PHASE I p 0 75 1 50 300 (n \\ \ \\ \\\\\ \\\ \ \ \ EX. SP-5 CS -4 ( ) i I \ \ O Z O c� \\ \\\ \�\ \\�\ \ \ \ \ \ \ \ \\ \ \ I I I I Q CB CATCH BASIN LL \ \ EX. MH-5.1A SB-4 \ \ \ \ \ \ \ �\ \ O \\\\\ \\ \\\\\\ \ \ \ \ \ \ \ \ \\ \ BURNSIDE RIDGE EX.\ EX. S&G-5.1 J 1 I LU MH MANHOLE ° o I \ \ \ \\\ \\ \ \ \ \ \ \ \ \ \ �\\�\ i� w OS OFFSITE uj \ \ \ \\ \\ \ \ \ \\ \ \ \ \ \ \ \ \ \ \ \ ESTATES NO. 4 \\\ - o \ \ \ \ \\\\\ \�\\\\ \\ \\ \ \ \ \ \ \ \ \\ \ \\ (FUTURE PHASE) \� �\ 0.5 I \ lb z PND POND m �� A EX. CB-5.1 B \ \ \ \ \ \\ \ \ \\ \\ \ \\ \ \ \ \ \ \ \ \\�\ 5.1 Q25: 0.33 CFS 4J 0 0 \ \ \ \ \ \ \\ \ \ \\\\\\\\\\\ \\ \ \ \ \ \ \ \ \\ _ S&G SAND & GREASE TRAP o \ \\\\\\\ \ \\\ \ \\ \\\\\ \\ \\ \ \ \ \ \ \ \ \ \ \ \ \ \ \\\ 0.72 Q100: 0.47 CFS I z SP SEEPAGE BED \ \ \ \ \` \ \\ \ \ \ \ \ \ \ \ \ \ \ \ \ , \�\\\ EX. CB-5.1A \ I TEMP TEMPORARY I I ❑ \ \ \ \ \ \ \\ \ \ \ \\\ \\ \ \ \ \ \ \ \ \ \ \ \ Q25: 0.33 CFS - I a \ \ \\ \ \ \ \ \ \\ \\ \ \\\ \\ \ \ \ \ \ \ \ \ \ \ \ \ 0.5 \ \ o \ \ \ \ \ \ \ \ \ \ \ \\\ \\ \ \ \ \ \ \ \ \ \ \ \ Q100: 0.47 CFS al a \ \ \ \\ \ \ \ \ \\ \\ \ \\ \ \ \ \ \ \ \ \ 5.2 \ \ \ 3 I \ \ \ \ \ \ \ \ \\ \\ \ \\ \\\\\\\\ \\ \ \ \ \ \ \ \ \ \ \\ 0.15 - J I I - -SB-8 IIII m a \ \ \ \ \ \\ \ \\ \ \ \ \\ \ \ \ \ \ \ \ \ \ - _ \ \ \ 0.5 _\ _E. IRRIGATOR STD MH-8C m N 5.3 - -a- - - - I I m m \ \ \ T- MH-8B 0 3 \ \ \ \ \ \ \ \ \ \ \\ \ \ \ \\ \\ \ \ \\ \ \ \ \ � _ `�\ \ \ \ \ \\ \ \\ 3.08 \ � \ o Z \ \ \ \ \ \ \ \ \ \ \ \ \ \\\ \\ \ \ \ \ \ \ \ \ - - \ \ ` \ \ \ \ m LU w LLJ \ \ \ \ \ \ \ \\ \ \ \\ \\\ \\ \ \ \ \ \ \ \ \ \ \ \\\\� 8.1 w U CD \ \ \ \ \ \ \ \ \ \\ \ \ \\ \\\ \\ \\ \ \ \ \ \ \ \ \ \ \ ��O\\\\ S Q25: 0.90 CFS a CB-8.1A c~n N \ \ \ \\ \\ \ \\ \ \ \\\\\\\\ \\\\\\�\\`�\\ \ \ \ \\\\\ - \\ \\ \ \ ��\\ \\\\% \\\ \ /ij,� 5.18 Q100: 1.25CFS Q25: 0.90CFS U w \ \ \ \ \ \ \ \ \ \ \ \\ \\ \\ \ \ \ \ \ \ \ \ \ \ \y \\ \ \ F = Q100: 1.25 CFS w a \ \ \ \ \ \ \ \ \ \ \ \ \\ \\\ \\ \ \ \ \ \ \ \ �� \ \ 'A \ a o w N \ \ \ \ \ \\ \\ \ \ O� \ w ❑ r I \ \ \ \ \ \ \ \ \ \ \ \ \ \\ \ \\\ \\ \\ \ \ \ \ \ \ \ \ \ \ \� \ <�\ \ \ \ \ I I � o z o \ \ \ \ \ \ \ \ \ \ \\ \ _ �Q�,\ �\ �i o LLJY o \ \ \ \ \ \\ \ \ \ \ � \ \ \\ \ \ \ \ "Y \ //� \ N \ \ \ \ \ \ \ \ \ \ \ \ \ \ \\\ \\\\\� � \ \ \ \ \ \ \ \ \ \\\` \ \ \� \ \ I M O a \ \ \\ \ \ \ \ \ \ \ \\\ \\�\\\\\\\� �\ � \ \ \ \ \ \ \\ \ \\ 1�� \\\O\\\ \\ \ 0.5 \\ S&G-9 I Q o LU o z LU Z_ U ° 9.1 \ I I 1 w w w g o I \ \ \ \ \ \ \ \\ \\ \ \\\ \ \ \�� \ \\\ \\\ \ \ \ \ \ \ \ \ 1 \ � ���� \\\\\ \ - o \ \ \ \ \ \ \\\ \ \ \ \\ \\\ \ \ \ \\ \ \\ I ��I / 1 ��� \\\� \ I ° \ \ \ \ \ \\\ \ \ \ \ l - - \\\� \ \\� \\\ \\ \ ``\ \ \ \ � �\ E. HOLSTEIN DR _ 11 OS-2.1 .m - - - - - - - - - - 1 \ SEAL N � m 0.34 D w r CB-9.1 B ° S�� EN 0.5 Q25: 0.34 CFS N N o , - 9.2 0.5 Q100: 0.47 CFS 'V � D z 0.09 10 CB-9.1A 9 ° 0.14 Q25: 0.34 CFS 2 C:) a Q100: 0.47 CFS C F 0 N U F44ER 8F' a o 0 N EXPIRES 10/31/25 nj J C) SHEET NO. N 0 rn C\1 CO co Y o PC.01 @ L 1 of 1