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HomeMy WebLinkAboutFISCHER PROPERTIES - PDP220007 - DOCUMENT MARKUPS - ROUND 3 - RESPONSE TO STAFF REVIEW COMMENTS (2) PRELIMINARY DRAINAGE REPORT FISCHER PROPERTIES FORT COLLINS, COLORADO AUGUST 24, 2022 NORTHERNENGINEERING.COM 970.221.4158 FORT COLLINS GREELEY This Drainage Report is consciously provided as a PDF. Please consider the environment before printing this document in its entirety. When a hard copy is necessary, we recommend double-sided printing. NORTHERNENGINEERING.COM | 970.221.4158 FORT COLLINS | GREELEY PRELIMINARY DRAINAGE REPORT: FISCHER PROPERTIES 11 | 11 1. LID Site Summary - New Impervious Area Total Area of Current Development 232,598 ft2 Total On-site Impervious Area 143,631 ft2 75% Required Minimum Area to be Treated by LID 107,723 ft2 Total On-site Impervious Area Treated by LID 127,813 ft2 Percent On-site Impervious Treated by LID 88.99% Additional Off-site Impervious Area Treated by LID 9,176 ft2 Percent Total Impervious Area Treated by LID 95.38% Total Impervious Area Treated by Traditional WQ 13,385 ft2 Percent Impervious Treated by Traditional Water Quality 9.32% Percent Impervious Area Treated by Traditional WQ or LID 104.70% Pond ID Extended Detention WQCV (CF) LID WQCV (CF) 100-Yr. Detention Vol. (CF) Total Volume (CF) 100-Yr. Detention WSEL(Ft) Peak Release (cfs) Pond 1 546.00 N/A 2,832.00 3,378.00 5,030.03 0.40 Pond 2 N/A 2,209.00 9,843.00 12,052.00 5,029.40 1.99 Pond 3 N/A 2,213.00 16,562.00 18,775.00 5,031.27 1.10 CHARACTER OF SURFACE1: Percentage Impervious 2-yr Runoff Coefficient 10-yr Runoff Coefficient 100-yr Runoff Coefficient Developed Asphalt .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………100%0.95 0.95 1.00 Concrete .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………100%0.95 0.95 1.00 Rooftop .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………90%0.95 0.95 1.00 Gravel .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………40%0.50 0.50 0.63 Pavers .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………40%0.50 0.50 0.63 Residential (Low Density).…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………50%0.55 0.55 0.69 Landscape or Pervious Surface Playgrounds .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………25%0.35 0.35 0.44 Lawns Clayey Soil .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………2%0.25 0.25 0.31 Lawns Sandy Soil .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………2%0.15 0.15 0.19 Notes: Basin ID Basin Area (ac) Area of Asphalt/Con crete (ac) Area of Concrete (ac) Area of Rooftop (ac) Area of Single Family (ac) Area of Gravel (ac) Area of Pavers (ac) Area of Playgrounds (ac) Area of Lawns (ac) Composite % Imperv. 2-year Composite Runoff Coefficient 10-year Composite Runoff Coefficient 100-year Composite Runoff Coefficient H1 2.742 0.00 0.06 0.26 0.28 0.00 0.00 2.49 17%0.39 0.39 0.46 H2 2.653 0.00 0.00 0.00 0.00 0.00 0.00 2.65 2%0.25 0.25 0.31 OS-1 0.133 0.105 0.03 80%0.81 0.81 0.86 OS-2 0.518 0.141 0.38 26%0.44 0.44 0.50 OS-3 0.397 0.00 0.097 0.30 25%0.43 0.43 0.49 OS-4 0.928 0.01 0.095 0.82 12%0.33 0.33 0.39 EXISTING CONDITION BASIN % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS 2) Runoff Coefficients are taken from the Fort Collins Stormwater Criteria Manual, Chapter 3. Table 3.2-1 and 3.2-2 1) Percentage impervious taken from the Fort Collins Stormwater Criteria Manual, Chapter 5, Table 4.1-2 and Table 4.1-3 Offsite Basins CHARACTER OF SURFACE1: Percentage Impervious 2-yr Runoff Coefficient 10-yr Runoff Coefficient 100-yr Runoff Coefficient Developed Asphalt .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………100%0.95 0.95 1.00 Concrete .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………100%0.95 0.95 1.00 Rooftop .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………90%0.95 0.95 1.00 Gravel .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………40%0.50 0.50 0.63 Pavers .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………40%0.50 0.50 0.63 Residential (Low Density).…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………50%0.55 0.55 0.69 Landscape or Pervious Surface Playgrounds .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………25%0.35 0.35 0.44 Lawns Clayey Soil .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………2%0.25 0.25 0.31 Lawns Sandy Soil .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………2%0.15 0.15 0.19 Notes: Basin ID Basin Area (ac) Area of Asphalt/Con crete (ac) Area of Concrete (ac) Area of Rooftop (ac) Area of Single Family (ac) Area of Gravel (ac) Area of Pavers (ac) Area of Playgrounds (ac) Area of Lawns (ac) Composite % Imperv. 2-year Composite Runoff Coefficient 10-year Composite Runoff Coefficient 100-year Composite Runoff Coefficient Notes 100 0.60 0.00 0.09 0.24 0.00 0.00 0.00 0.00 0.28 51%0.63 0.63 0.69 Detention Pond 1 200 1.83 0.57 0.43 0.52 0.00 0.00 0.00 0.00 0.30 81%0.83 0.83 0.89 Detention Pond 2 300 2.64 0.59 0.20 0.00 1.31 0.00 0.00 0.00 0.55 55%0.61 0.61 0.70 Detention Pond 3 OF-1 0.23 0.00 0.02 0.00 0.00 0.00 0.00 0.00 0.20 13%0.33 0.33 0.39 OF-2 0.04 0.02 0.01 0.00 0.00 0.00 0.00 0.00 0.02 64%0.70 0.70 0.75 Offsite Basins OS-1 0.13 0.11 0.00 0.00 0.00 0.00 0.00 0.00 0.03 80%0.81 0.81 0.86 OS-2 0.52 0.00 0.00 0.14 0.00 0.00 0.00 0.00 0.38 26%0.44 0.44 0.50 OS-3 0.40 0.00 0.00 0.10 0.00 0.00 0.00 0.00 0.30 25%0.43 0.43 0.49 OS-4 0.93 0.00 0.01 0.09 0.00 0.00 0.00 0.00 0.82 12%0.33 0.33 0.39 Combined Basins 200, OS-4 2.76 0.57 0.44 0.62 0.00 0.00 0.00 0.00 1.12 58%0.67 0.67 0.72 Tributary Area to DP 200 300, OS-1, OS2, OS-3 3.69 0.69 0.20 0.24 1.31 0.00 0.00 0.00 1.25 48%0.57 0.57 0.66 Tributary Area to DP 300 OF-1, OF-2 0.27 0.02 0.03 0.00 0.00 0.00 0.00 0.00 0.22 21%0.38 0.38 0.44 Undetained Basins 300, OS-3 3.04 0.59 0.20 0.10 1.31 0.00 0.00 0.00 0.84 51%0.58 0.58 0.67 LID - Rain Garden 200, OS-4 2.76 0.57 0.44 0.62 0.00 0.00 0.00 0.00 1.12 58%0.67 0.67 0.72 LID - Underground Stormtech Total On-Site 5.34 1.18 0.74 0.76 1.31 0.00 0.00 0.00 1.34 62%0.68 0.68 0.75 Total On-Site and Off-site 7.32 1.29 0.76 1.10 1.31 0.00 0.00 0.00 2.86 51%0.60 0.60 0.68 *The combined basins indicating tributary area to DP 200 and DP 300 provide the total area draining to these design points. These are not indicative of the total basin being detained in the Ponds 2 and 3 2) Runoff Coefficients are taken from the Fort Collins Stormwater Criteria Manual, Chapter 3. Table 3.2-1 and 3.2-2 1) Percentage impervious taken from the Fort Collins Stormwater Criteria Manual, Chapter 5, Table 4.1-2 and Table 4.1-3 DEVELOPED BASIN % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS Pond No :1 100 100-yr 0.69 5.00 min 2832 ft3 0.60 acres 0.07 ac-ft Max Release Rate =0.40 cfs Time (min) Ft Collins 100-yr Intensity (in/hr) Inflow Volume (ft3) Outflow Adjustment Factor Qav (cfs) Outflow Volume (ft3) Storage Volume (ft3) 5 9.950 1236 1.00 0.40 120 1116 10 7.720 1918 1.00 0.40 240 1678 15 6.520 2429 1.00 0.40 360 2069 20 5.600 2782 1.00 0.40 480 2302 25 4.980 3093 1.00 0.40 600 2493 30 4.520 3368 1.00 0.40 720 2648 35 4.080 3547 1.00 0.40 840 2707 40 3.740 3716 1.00 0.40 960 2756 45 3.460 3868 1.00 0.40 1080 2788 50 3.230 4012 1.00 0.40 1200 2812 55 3.030 4140 1.00 0.40 1320 2820 60 2.860 4263 1.00 0.40 1440 2823 65 2.720 4392 1.00 0.40 1560 2832 70 2.590 4503 1.00 0.40 1680 2823 75 2.480 4620 1.00 0.40 1800 2820 80 2.380 4730 1.00 0.40 1920 2810 85 2.290 4835 1.00 0.40 2040 2795 90 2.210 4941 1.00 0.40 2160 2781 95 2.130 5026 1.00 0.40 2280 2746 100 2.060 5117 1.00 0.40 2400 2717 105 2.000 5216 1.00 0.40 2520 2696 110 1.940 5301 1.00 0.40 2640 2661 115 1.890 5399 1.00 0.40 2760 2639 120 1.840 5485 1.00 0.40 2880 2605 *Note: Using the method described in Urban Storm Drainage Criteria Manual Volume 2. A = Tc = Project Location : Design Point C = Design Storm DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF Input Variables Results Required Detention Volume Fort Collins, CO 1382-002 Fischer Subdivision Project Number : Project Name : 8/23/2022 2:46 PM 1382-002_FAA_Pond 1.xls FAA Northern Engineering Services Pond No :2 200 100-yr 0.89 5.00 min 9843 ft3 1.83 acres 0.23 ac-ft Max Release Rate =1.99 cfs Time (min) Ft Collins 100-yr Intensity (in/hr) Inflow Volume (ft3) Outflow Adjustment Factor Qav (cfs) Outflow Volume (ft3) Storage Volume (ft3) 5 9.950 4862 1.00 1.99 597 4265 10 7.720 7544 1.00 1.99 1194 6350 15 6.520 9557 1.00 1.99 1791 7766 20 5.600 10945 1.00 1.99 2388 8557 25 4.980 12166 1.00 1.99 2985 9181 30 4.520 13251 1.00 1.99 3582 9669 35 4.080 13955 1.00 1.99 4179 9776 40 3.740 14619 1.00 1.99 4776 9843 45 3.460 15215 1.00 1.99 5373 9842 50 3.230 15782 1.00 1.99 5970 9812 55 3.030 16285 1.00 1.99 6567 9718 60 2.860 16769 1.00 1.99 7164 9605 65 2.720 17277 1.00 1.99 7761 9516 70 2.590 17717 1.00 1.99 8358 9359 75 2.480 18176 1.00 1.99 8955 9221 80 2.380 18606 1.00 1.99 9552 9054 85 2.290 19022 1.00 1.99 10149 8873 90 2.210 19437 1.00 1.99 10746 8691 95 2.130 19774 1.00 1.99 11343 8431 100 2.060 20131 1.00 1.99 11940 8191 105 2.000 20522 1.00 1.99 12537 7985 110 1.940 20854 1.00 1.99 13134 7720 115 1.890 21240 1.00 1.99 13731 7509 120 1.840 21577 1.00 1.99 14328 7249 *Note: Using the method described in Urban Storm Drainage Criteria Manual Volume 2. DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF Input Variables Results Required Detention Volume Fort Collins, CO 1382-002 Fischer Subdivision Project Number : Project Name : A = Tc = Project Location : Design Point C = Design Storm 8/23/2022 2:49 PM 1382-002_FAA_Pond 2.xls FAA Northern Engineering Services Pond No :3 300 100-yr 0.70 5.00 min 16562 ft3 2.64 acres 0.38 ac-ft Max Release Rate =1.10 cfs Time (min) Ft Collins 100-yr Intensity (in/hr) Inflow Volume (ft3) Outflow Adjustment Factor Qav (cfs) Outflow Volume (ft3) Storage Volume (ft3) 5 9.950 5516 1.00 1.10 330 5186 10 7.720 8560 1.00 1.10 660 7900 15 6.520 10844 1.00 1.10 990 9854 20 5.600 12419 1.00 1.10 1320 11099 25 4.980 13805 1.00 1.10 1650 12155 30 4.520 15035 1.00 1.10 1980 13055 35 4.080 15834 1.00 1.10 2310 13524 40 3.740 16588 1.00 1.10 2640 13948 45 3.460 17264 1.00 1.10 2970 14294 50 3.230 17907 1.00 1.10 3300 14607 55 3.030 18478 1.00 1.10 3630 14848 60 2.860 19027 1.00 1.10 3960 15067 65 2.720 19604 1.00 1.10 4290 15314 70 2.590 20103 1.00 1.10 4620 15483 75 2.480 20624 1.00 1.10 4950 15674 80 2.380 21112 1.00 1.10 5280 15832 85 2.290 21583 1.00 1.10 5610 15973 90 2.210 22054 1.00 1.10 5940 16114 95 2.130 22437 1.00 1.10 6270 16167 100 2.060 22841 1.00 1.10 6600 16241 105 2.000 23285 1.00 1.10 6930 16355 110 1.940 23662 1.00 1.10 7260 16402 115 1.890 24100 1.00 1.10 7590 16510 120 1.840 24482 1.00 1.10 7920 16562 *Note: Using the method described in Urban Storm Drainage Criteria Manual Volume 2. A = Tc = Project Location : Design Point C = Design Storm DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF Input Variables Results Required Detention Volume Fort Collins, CO 1382-002 Fischer Subdivision Project Number : Project Name : 8/23/2022 2:48 PM 1382-002_FAA_Pond 3.xls FAA Northern Engineering Services Pond No : 200 WQ 0.72 5.00 min 2056 ft3 2.76 acres 0.05 ac-ft Max Release Rate =0.45 cfs Time (min) Ft Collins WQ Intensity (in/hr) Inflow Volume (ft3) Outflow Adjustment Factor QWQ (cfs) Outflow Volume (ft3) Storage Volume (ft3) 5 1.425 850 1.00 0.45 135 715 10 1.105 1318 1.00 0.45 270 1048 15 0.935 1672 0.67 0.30 270 1402 20 0.805 1920 0.63 0.28 338 1582 25 0.715 2131 0.60 0.27 405 1726 30 0.650 2325 0.58 0.26 473 1853 35 0.585 2441 0.57 0.26 540 1901 40 0.535 2552 0.56 0.25 608 1944 45 0.495 2656 0.56 0.25 675 1981 50 0.460 2742 0.55 0.25 743 2000 55 0.435 2853 0.55 0.25 810 2043 60 0.410 2933 0.54 0.24 878 2056 65 0.385 2984 0.54 0.24 945 2039 70 0.365 3046 0.54 0.24 1013 2034 75 0.345 3085 0.53 0.24 1080 2005 80 0.330 3148 0.53 0.24 1148 2000 85 0.315 3192 0.53 0.24 1215 1977 90 0.305 3273 0.53 0.24 1283 1990 95 0.290 3285 0.53 0.24 1350 1935 100 0.280 3338 0.53 0.24 1418 1921 105 0.270 3380 0.52 0.24 1485 1895 110 0.260 3410 0.52 0.24 1553 1858 115 0.255 3496 0.52 0.23 1620 1876 120 0.245 3505 0.52 0.23 1688 1818 *Note: Using the method described in FCSCM Chapter 6 Section 2.3 DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF Input Variables Results Required Detention Volume Fort Collins, Colorado 1382-002 Fischer Subdivission Project Number : Project Name : Chambers 2 A = Tc = Project Location : Design Point C = Design Storm Page 1 of 1 1382-002 Chamber Summary 2.xlsx Vault ID Total Required WQ Volume (cf) Flow, WQ (cfs) Chamber Type Chamber Release Ratea (cfs) Chamber Volumeb (cf) Installed Chamber w/ Aggregatec (cf) Minimum No. of Chambersd Total Release Ratee (cfs) Required Storage Volume by FAA Method (cf) Minimum No. of Chambersf Provided Number of Chambers Provided Release Rate (cfs) Storage Provided within the Chambersg (cf) Total Installed System Volumeh (cf) Pond2 2209 2.27 MC-3500 0.024 109.90 158.73 14 0.33 2056 19 19 0.45 2088 3968 a. Release rate per chamber, limited by flow through geotextile with accumulated sediment. b. Volume within chamber only, not accounting for void spaces in surrounding aggregate. c. Volume includes chamber and void spaces (30%) in surrounding aggregate, per chamber unit. d. Number of chambers required to provide full WQCV within total installed system, including aggregate. e. Release rate per chamber times number of chambers. f. Number of chambers required to provide required FAA storage volume stored within the chamber only (no aggregate storage). g. Volume provided in chambers only (no aggregate storage). This number must meet or exceed the required FAA storage volume. h. System volume includes total number of chambers, plus surrounding aggregate. This number must meet or exceed the required WQCV. Chamber Configuration Summary P:\1382-002\Drainage\LID\1382-002 Chamber Summary 2.xlsx