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DRAINAGE CALCULATIONS 2 - 18-00305 - Approx. 1000 Yellowstone Hwy - Thomson Farms - The Grove Final Plat Phase 1
SALT LAKE CITY 45 West 10000 South, Ste 500 Sandy, UT 84070 P 801.255.0529 LAYTON 1485 W Hill Field Rd, Ste 204 Layton, UT 84041 P 801.547.1100 CEDAR CITY 1870 North Main Street, Ste 104 Cedar City, UT 84721 P 435.865.1453 TOOELE 169 N. Main Street, Unit 1 Tooele, UT 84074 P 435.843.3590 RICHFIELD 225 North 100 East Richfield, UT 84701 P 435.896.2983 www.ensigneng.com Civil Engineering Land Surveying Structural Design Water Design Aerial Technologies March 28, 2018 Drainage Narrative Thomson Farms PUD The proposed site is located at approximately Old US Highway 191 and Stegelmeier Lane in Rexburg Idaho. The proposed site has been designed to meet the drainage requirements of Rexburg City. From discussions with city staff a 25-year 1-hour event of 0.9 inches was used. This rainfall event was then distributed across a local IDF curve. The 24-hour, 25-year storm event was used to size retention areas and the 10-year storm event was used to size underground conveyance systems. The Rational method was used to determine the required retention volumes for the site. Both surface and underground retention are proposed for the site. Based on the geotechnical report gravels were found across the site from 5 to 7 feet below the existing surface. For this gravel percolation rate was estimated to be 10 inches per hour. In the public road areas, Infiltrator rows are proposed to handle runoff. In the townhome, apartment, and commercial areas surface retention ponds with an infiltration beds are proposed. See the attached storm drain calculations for each of the retention basins and infiltrators. Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 0.31 acres Cp :0.90 0.07 acres Cl :0.20 0.38 acres WEIGHTED C:0.78 995 ft2 10 in/hr 0.230 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 0.29 2.75 600 484 138 346 15 0.29 2.25 900 594 207 387 20 0.29 1.75 1,200 616 276 340 30 0.29 1.40 1,800 740 414 325 40 0.29 1.25 2,400 881 553 328 50 0.29 1.05 3,000 925 691 234 60 0.29 0.90 3,600 951 829 122 120 0.29 0.55 7,200 1,162 1,658 -496 180 0.29 0.41 10,800 1,300 2,487 -1,187 240 0.29 0.33 14,400 1,395 3,316 -1,921 300 0.29 0.28 18,000 1,479 4,145 -2,666 360 0.29 0.25 21,600 1,585 4,974 -3,389 480 0.29 0.19 28,800 1,606 6,632 -5,026 600 0.29 0.16 36,000 1,691 8,290 -6,599 720 0.29 0.14 43,200 1,775 9,948 -8,173 1080 0.29 0.11 64,800 2,092 14,922 -12,830 1440 0.29 0.08 86,400 2,130 19,896 -17,765 387 450 Percolation Area Percolation Rate Total Percolation Rate TOTAL AREA (A): Runoff Calculations NOTE: 25 Year Storm STORAGE REQUIRED : STORAGE PROVIDED : LANDSCAPE AREA (Al): BASIN 01 9-Feb-2018 INFILTRATOR RETENTION CALCULATION Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 0.24 acres Cp :0.90 0.04 acres Cl :0.20 0.29 acres WEIGHTED C:0.80 711 ft2 10 in/hr 0.165 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 0.23 2.75 600 377 99 278 15 0.23 2.25 900 463 148 315 20 0.23 1.75 1,200 480 198 282 30 0.23 1.40 1,800 576 296 280 40 0.23 1.25 2,400 686 395 290 50 0.23 1.05 3,000 720 494 226 60 0.23 0.90 3,600 741 593 148 120 0.23 0.55 7,200 905 1,186 -281 180 0.23 0.41 10,800 1,012 1,778 -766 240 0.23 0.33 14,400 1,086 2,371 -1,285 300 0.23 0.28 18,000 1,152 2,964 -1,812 360 0.23 0.25 21,600 1,234 3,557 -2,323 480 0.23 0.19 28,800 1,251 4,742 -3,492 600 0.23 0.16 36,000 1,316 5,928 -4,611 720 0.23 0.14 43,200 1,382 7,114 -5,731 1080 0.23 0.11 64,800 1,629 10,670 -9,041 1440 0.23 0.08 86,400 1,659 14,227 -12,568 315 315 BASIN 02 STORAGE PROVIDED : LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : 9-Feb-2018 INFILTRATOR RETENTION CALCULATION Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 0.22 acres Cp :0.90 0.04 acres Cl :0.20 0.26 acres WEIGHTED C:0.80 711 ft2 10 in/hr 0.165 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 0.21 2.75 600 340 99 241 15 0.21 2.25 900 417 148 269 20 0.21 1.75 1,200 432 198 235 30 0.21 1.40 1,800 519 296 223 40 0.21 1.25 2,400 618 395 223 50 0.21 1.05 3,000 649 494 155 60 0.21 0.90 3,600 667 593 74 120 0.21 0.55 7,200 816 1,186 -370 180 0.21 0.41 10,800 912 1,778 -866 240 0.21 0.33 14,400 979 2,371 -1,393 300 0.21 0.28 18,000 1,038 2,964 -1,926 360 0.21 0.25 21,600 1,112 3,557 -2,445 480 0.21 0.19 28,800 1,127 4,742 -3,615 600 0.21 0.16 36,000 1,186 5,928 -4,742 720 0.21 0.14 43,200 1,246 7,114 -5,868 1080 0.21 0.11 64,800 1,468 10,670 -9,202 1440 0.21 0.08 86,400 1,495 14,227 -12,732 269 315 BASIN 03 STORAGE PROVIDED : LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : 9-Feb-2018 INFILTRATOR RETENTION CALCULATION Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 0.31 acres Cp :0.90 0.07 acres Cl :0.20 0.38 acres WEIGHTED C:0.78 995 ft2 10 in/hr 0.230 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 0.29 2.75 600 483 138 345 15 0.29 2.25 900 593 207 385 20 0.29 1.75 1,200 615 276 338 30 0.29 1.40 1,800 738 414 323 40 0.29 1.25 2,400 878 553 325 50 0.29 1.05 3,000 922 691 231 60 0.29 0.90 3,600 948 829 119 120 0.29 0.55 7,200 1,159 1,658 -499 180 0.29 0.41 10,800 1,296 2,487 -1,191 240 0.29 0.33 14,400 1,391 3,316 -1,925 300 0.29 0.28 18,000 1,475 4,145 -2,670 360 0.29 0.25 21,600 1,581 4,974 -3,393 480 0.29 0.19 28,800 1,602 6,632 -5,030 600 0.29 0.16 36,000 1,686 8,290 -6,604 720 0.29 0.14 43,200 1,770 9,948 -8,178 1080 0.29 0.11 64,800 2,086 14,922 -12,835 1440 0.29 0.08 86,400 2,124 19,896 -17,771 385 450 BASIN 04 STORAGE PROVIDED : LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : 9-Feb-2018 INFILTRATOR RETENTION CALCULATION Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 0.46 acres Cp :0.90 0.08 acres Cl :0.20 0.54 acres WEIGHTED C:0.79 1373 ft2 10 in/hr 0.318 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 0.43 2.75 600 705 191 515 15 0.43 2.25 900 866 286 580 20 0.43 1.75 1,200 898 381 516 30 0.43 1.40 1,800 1,077 572 505 40 0.43 1.25 2,400 1,282 763 520 50 0.43 1.05 3,000 1,346 953 393 60 0.43 0.90 3,600 1,385 1,144 241 120 0.43 0.55 7,200 1,693 2,288 -595 180 0.43 0.41 10,800 1,893 3,432 -1,539 240 0.43 0.33 14,400 2,031 4,576 -2,544 300 0.43 0.28 18,000 2,154 5,720 -3,565 360 0.43 0.25 21,600 2,308 6,864 -4,555 480 0.43 0.19 28,800 2,339 9,151 -6,812 600 0.43 0.16 36,000 2,462 11,439 -8,977 720 0.43 0.14 43,200 2,585 13,727 -11,142 1080 0.43 0.11 64,800 3,047 20,591 -17,544 1440 0.43 0.08 86,400 3,102 27,454 -24,352 580 630 BASIN 05 STORAGE PROVIDED : LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : 9-Feb-2018 INFILTRATOR RETENTION CALCULATION Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 0.32 acres Cp :0.90 0.06 acres Cl :0.20 0.38 acres WEIGHTED C:0.79 995 ft2 10 in/hr 0.230 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 0.30 2.75 600 491 138 353 15 0.30 2.25 900 602 207 395 20 0.30 1.75 1,200 625 276 348 30 0.30 1.40 1,800 750 414 335 40 0.30 1.25 2,400 892 553 340 50 0.30 1.05 3,000 937 691 246 60 0.30 0.90 3,600 964 829 135 120 0.30 0.55 7,200 1,178 1,658 -480 180 0.30 0.41 10,800 1,317 2,487 -1,170 240 0.30 0.33 14,400 1,414 3,316 -1,902 300 0.30 0.28 18,000 1,499 4,145 -2,646 360 0.30 0.25 21,600 1,606 4,974 -3,368 480 0.30 0.19 28,800 1,628 6,632 -5,004 600 0.30 0.16 36,000 1,713 8,290 -6,577 720 0.30 0.14 43,200 1,799 9,948 -8,149 1080 0.30 0.11 64,800 2,120 14,922 -12,802 1440 0.30 0.08 86,400 2,159 19,896 -17,737 395 450 BASIN 06 STORAGE PROVIDED : LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : 9-Feb-2018 INFILTRATOR RETENTION CALCULATION Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 0.09 acres Cp :0.90 0.02 acres Cl :0.20 0.10 acres WEIGHTED C:0.78 333 ft2 10 in/hr 0.077 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 0.08 2.75 600 133 46 86 15 0.08 2.25 900 163 69 93 20 0.08 1.75 1,200 169 93 76 30 0.08 1.40 1,800 202 139 64 40 0.08 1.25 2,400 241 185 56 50 0.08 1.05 3,000 253 232 21 60 0.08 0.90 3,600 260 278 -18 120 0.08 0.55 7,200 318 556 -238 180 0.08 0.41 10,800 356 834 -478 240 0.08 0.33 14,400 382 1,111 -730 300 0.08 0.28 18,000 405 1,389 -984 360 0.08 0.25 21,600 434 1,667 -1,233 480 0.08 0.19 28,800 440 2,223 -1,783 600 0.08 0.16 36,000 463 2,779 -2,316 720 0.08 0.14 43,200 486 3,334 -2,849 1080 0.08 0.11 64,800 573 5,002 -4,429 1440 0.08 0.08 86,400 583 6,669 -6,086 93 135 BASIN 07 STORAGE PROVIDED : LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : 9-Feb-2018 INFILTRATOR RETENTION CALCULATION Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 0.35 acres Cp :0.90 0.08 acres Cl :0.20 0.43 acres WEIGHTED C:0.78 1089 ft2 10 in/hr 0.252 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 0.33 2.75 600 551 151 400 15 0.33 2.25 900 677 227 450 20 0.33 1.75 1,200 702 303 399 30 0.33 1.40 1,800 842 454 388 40 0.33 1.25 2,400 1,002 605 397 50 0.33 1.05 3,000 1,052 756 296 60 0.33 0.90 3,600 1,082 908 175 120 0.33 0.55 7,200 1,323 1,815 -493 180 0.33 0.41 10,800 1,479 2,723 -1,244 240 0.33 0.33 14,400 1,588 3,631 -2,043 300 0.33 0.28 18,000 1,684 4,539 -2,855 360 0.33 0.25 21,600 1,804 5,446 -3,642 480 0.33 0.19 28,800 1,828 7,262 -5,434 600 0.33 0.16 36,000 1,924 9,077 -7,153 720 0.33 0.14 43,200 2,021 10,893 -8,872 1080 0.33 0.11 64,800 2,381 16,339 -13,958 1440 0.33 0.08 86,400 2,425 21,785 -19,361 450 495 BASIN 08 STORAGE PROVIDED : LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : 9-Feb-2018 INFILTRATOR RETENTION CALCULATION Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 0.38 acres Cp :0.90 0.05 acres Cl :0.20 0.44 acres WEIGHTED C:0.81 1089 ft2 10 in/hr 0.252 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 0.36 2.75 600 588 151 437 15 0.36 2.25 900 722 227 495 20 0.36 1.75 1,200 748 303 446 30 0.36 1.40 1,800 898 454 444 40 0.36 1.25 2,400 1,069 605 464 50 0.36 1.05 3,000 1,123 756 366 60 0.36 0.90 3,600 1,155 908 247 120 0.36 0.55 7,200 1,411 1,815 -404 180 0.36 0.41 10,800 1,578 2,723 -1,145 240 0.36 0.33 14,400 1,693 3,631 -1,937 300 0.36 0.28 18,000 1,796 4,539 -2,743 360 0.36 0.25 21,600 1,924 5,446 -3,522 480 0.36 0.19 28,800 1,950 7,262 -5,312 600 0.36 0.16 36,000 2,053 9,077 -7,025 720 0.36 0.14 43,200 2,155 10,893 -8,737 1080 0.36 0.11 64,800 2,540 16,339 -13,799 1440 0.36 0.08 86,400 2,586 21,785 -19,199 495 495 BASIN 09 STORAGE PROVIDED : LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : 9-Feb-2018 INFILTRATOR RETENTION CALCULATION Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 0.26 acres Cp :0.90 0.97 acres Cl :0.20 1.23 acres WEIGHTED C:0.35 1373 ft2 10 in/hr 0.318 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 0.43 2.75 600 713 191 522 15 0.43 2.25 900 875 286 589 20 0.43 1.75 1,200 907 381 526 30 0.43 1.40 1,800 1,089 572 517 40 0.43 1.25 2,400 1,296 763 534 50 0.43 1.05 3,000 1,361 953 408 60 0.43 0.90 3,600 1,400 1,144 256 120 0.43 0.55 7,200 1,711 2,288 -577 180 0.43 0.41 10,800 1,913 3,432 -1,518 240 0.43 0.33 14,400 2,053 4,576 -2,522 300 0.43 0.28 18,000 2,178 5,720 -3,542 360 0.43 0.25 21,600 2,333 6,864 -4,530 480 0.43 0.19 28,800 2,364 9,151 -6,787 600 0.43 0.16 36,000 2,489 11,439 -8,950 720 0.43 0.14 43,200 2,613 13,727 -11,114 1080 0.43 0.11 64,800 3,080 20,591 -17,511 1440 0.43 0.08 86,400 3,136 27,454 -24,318 589 630 BASIN 10 STORAGE PROVIDED : LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : 9-Feb-2018 INFILTRATOR RETENTION CALCULATION Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 0.43 acres Cp :0.90 1.58 acres Cl :0.20 2.01 acres WEIGHTED C:0.35 2129 ft2 10 in/hr 0.493 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 0.70 2.75 600 1,159 296 864 15 0.70 2.25 900 1,423 443 979 20 0.70 1.75 1,200 1,475 591 884 30 0.70 1.40 1,800 1,770 887 883 40 0.70 1.25 2,400 2,108 1,183 925 50 0.70 1.05 3,000 2,213 1,478 735 60 0.70 0.90 3,600 2,276 1,774 502 120 0.70 0.55 7,200 2,782 3,548 -766 180 0.70 0.41 10,800 3,111 5,321 -2,211 240 0.70 0.33 14,400 3,338 7,095 -3,757 300 0.70 0.28 18,000 3,541 8,869 -5,328 360 0.70 0.25 21,600 3,794 10,643 -6,849 480 0.70 0.19 28,800 3,844 14,190 -10,346 600 0.70 0.16 36,000 4,047 17,738 -13,691 720 0.70 0.14 43,200 4,249 21,285 -17,037 1080 0.70 0.11 64,800 5,008 31,928 -26,921 1440 0.70 0.08 86,400 5,099 42,571 -37,472 979 990 BASIN 11 STORAGE PROVIDED : LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : 9-Feb-2018 INFILTRATOR RETENTION CALCULATION Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 1.21 acres Cp :0.90 4.43 acres Cl :0.20 5.64 acres WEIGHTED C:0.35 5908 ft2 10 in/hr 1.368 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 1.97 2.75 600 3,256 821 2,436 15 1.97 2.25 900 3,996 1,231 2,766 20 1.97 1.75 1,200 4,144 1,641 2,503 30 1.97 1.40 1,800 4,973 2,462 2,512 40 1.97 1.25 2,400 5,921 3,282 2,638 50 1.97 1.05 3,000 6,217 4,103 2,114 60 1.97 0.90 3,600 6,394 4,923 1,471 120 1.97 0.55 7,200 7,815 9,846 -2,031 180 1.97 0.41 10,800 8,739 14,769 -6,031 240 1.97 0.33 14,400 9,378 19,692 -10,314 300 1.97 0.28 18,000 9,947 24,615 -14,669 360 1.97 0.25 21,600 10,657 29,539 -18,882 480 1.97 0.19 28,800 10,799 39,385 -28,586 600 1.97 0.16 36,000 11,367 49,231 -37,863 720 1.97 0.14 43,200 11,936 59,077 -47,141 1080 1.97 0.11 64,800 14,067 88,616 -74,548 1440 1.97 0.08 86,400 14,323 118,154 -103,831 2,766 2,790 BASIN 12 STORAGE PROVIDED : LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : 9-Feb-2018 INFILTRATOR RETENTION CALCULATION Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 12.59 acres Cp :0.90 3.49 acres Cl :0.20 16.08 acres WEIGHTED C:0.75 2160 ft2 10 in/hr 0.500 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 12.03 2.75 600 19,849 300 19,549 15 12.03 2.25 900 24,360 450 23,910 20 12.03 1.75 1,200 25,262 600 24,662 30 12.03 1.40 1,800 30,314 900 29,414 40 12.03 1.25 2,400 36,089 1,200 34,889 50 12.03 1.05 3,000 37,893 1,500 36,393 60 12.03 0.90 3,600 38,976 1,800 37,176 120 12.03 0.55 7,200 47,637 3,600 44,037 180 12.03 0.41 10,800 53,267 5,400 47,867 240 12.03 0.33 14,400 57,164 7,200 49,964 300 12.03 0.28 18,000 60,629 9,000 51,629 360 12.03 0.25 21,600 64,959 10,800 54,159 480 12.03 0.19 28,800 65,825 14,400 51,425 600 12.03 0.16 36,000 69,290 18,000 51,290 720 12.03 0.14 43,200 72,754 21,600 51,154 1080 12.03 0.11 64,800 85,746 32,400 53,346 1440 12.03 0.08 86,400 87,305 43,200 44,105 54,159 59,328 BASIN 13 STORAGE PROVIDED : LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : 9-Feb-2018 INFILTRATOR RETENTION CALCULATION Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 7.81 acres Cp :0.90 6.32 acres Cl :0.20 14.13 acres WEIGHTED C:0.59 1800 ft2 10 in/hr 0.417 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 8.29 2.75 600 13,686 250 13,436 15 8.29 2.25 900 16,796 375 16,421 20 8.29 1.75 1,200 17,418 500 16,918 30 8.29 1.40 1,800 20,902 750 20,152 40 8.29 1.25 2,400 24,883 1,000 23,883 50 8.29 1.05 3,000 26,127 1,250 24,877 60 8.29 0.90 3,600 26,874 1,500 25,374 120 8.29 0.55 7,200 32,846 3,000 29,846 180 8.29 0.41 10,800 36,728 4,500 32,228 240 8.29 0.33 14,400 39,415 6,000 33,415 300 8.29 0.28 18,000 41,804 7,500 34,304 360 8.29 0.25 21,600 44,790 9,000 35,790 480 8.29 0.19 28,800 45,387 12,000 33,387 600 8.29 0.16 36,000 47,776 15,000 32,776 720 8.29 0.14 43,200 50,165 18,000 32,165 1080 8.29 0.11 64,800 59,123 27,000 32,123 1440 8.29 0.08 86,400 60,198 36,000 24,198 35,790 42,314 BASIN 14 STORAGE PROVIDED : LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : 9-Feb-2018 INFILTRATOR RETENTION CALCULATION Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 7.99 acres Cp :0.90 6.05 acres Cl :0.20 14.04 acres WEIGHTED C:0.60 1200 ft2 10 in/hr 0.278 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 8.40 2.75 600 13,857 167 13,691 15 8.40 2.25 900 17,007 250 16,757 20 8.40 1.75 1,200 17,637 333 17,303 30 8.40 1.40 1,800 21,164 500 20,664 40 8.40 1.25 2,400 25,195 667 24,529 50 8.40 1.05 3,000 26,455 833 25,622 60 8.40 0.90 3,600 27,211 1,000 26,211 120 8.40 0.55 7,200 33,258 2,000 31,258 180 8.40 0.41 10,800 37,188 3,000 34,188 240 8.40 0.33 14,400 39,909 4,000 35,909 300 8.40 0.28 18,000 42,328 5,000 37,328 360 8.40 0.25 21,600 45,351 6,000 39,351 480 8.40 0.19 28,800 45,956 8,000 37,956 600 8.40 0.16 36,000 48,375 10,000 38,375 720 8.40 0.14 43,200 50,793 12,000 38,793 1080 8.40 0.11 64,800 59,864 18,000 41,864 1440 8.40 0.08 86,400 60,952 24,000 36,952 41,864 42,851 BASIN 15 STORAGE PROVIDED : LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : 9-Feb-2018 INFILTRATOR RETENTION CALCULATION Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 0.38 acres Cp :0.90 0.09 acres Cl :0.20 0.47 acres WEIGHTED C:0.76 1184 ft2 10 in/hr 0.274 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 0.36 2.75 600 589 164 424 15 0.36 2.25 900 723 247 476 20 0.36 1.75 1,200 749 329 421 30 0.36 1.40 1,800 899 493 406 40 0.36 1.25 2,400 1,071 658 413 50 0.36 1.05 3,000 1,124 822 302 60 0.36 0.90 3,600 1,156 986 170 120 0.36 0.55 7,200 1,413 1,973 -560 180 0.36 0.41 10,800 1,580 2,959 -1,379 240 0.36 0.33 14,400 1,696 3,946 -2,250 300 0.36 0.28 18,000 1,798 4,932 -3,134 360 0.36 0.25 21,600 1,927 5,919 -3,992 480 0.36 0.19 28,800 1,953 7,892 -5,939 600 0.36 0.16 36,000 2,055 9,865 -7,809 720 0.36 0.14 43,200 2,158 11,838 -9,679 1080 0.36 0.11 64,800 2,544 17,756 -15,213 1440 0.36 0.08 86,400 2,590 23,675 -21,085 476 540 BASIN 16 STORAGE PROVIDED : LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : 9-Feb-2018 INFILTRATOR RETENTION CALCULATION Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 0.46 acres Cp :0.90 0.02 acres Cl :0.20 0.48 acres WEIGHTED C:0.87 1278 ft2 10 in/hr 0.296 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 0.42 2.75 600 689 178 511 15 0.42 2.25 900 845 266 579 20 0.42 1.75 1,200 877 355 522 30 0.42 1.40 1,800 1,052 533 519 40 0.42 1.25 2,400 1,252 710 542 50 0.42 1.05 3,000 1,315 888 427 60 0.42 0.90 3,600 1,352 1,065 287 120 0.42 0.55 7,200 1,653 2,130 -477 180 0.42 0.41 10,800 1,848 3,196 -1,347 240 0.42 0.33 14,400 1,984 4,261 -2,277 300 0.42 0.28 18,000 2,104 5,326 -3,222 360 0.42 0.25 21,600 2,254 6,391 -4,137 480 0.42 0.19 28,800 2,284 8,522 -6,237 600 0.42 0.16 36,000 2,404 10,652 -8,248 720 0.42 0.14 43,200 2,525 12,782 -10,258 1080 0.42 0.11 64,800 2,975 19,173 -16,198 1440 0.42 0.08 86,400 3,030 25,565 -22,535 579 585 BASIN 17 STORAGE PROVIDED : LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : 9-Feb-2018 INFILTRATOR RETENTION CALCULATION Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 0.16 acres Cp :0.90 0.03 acres Cl :0.20 0.18 acres WEIGHTED C:0.80 522 ft2 10 in/hr 0.121 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 0.15 2.75 600 242 73 170 15 0.15 2.25 900 297 109 189 20 0.15 1.75 1,200 308 145 163 30 0.15 1.40 1,800 370 218 152 40 0.15 1.25 2,400 441 290 150 50 0.15 1.05 3,000 463 363 100 60 0.15 0.90 3,600 476 435 41 120 0.15 0.55 7,200 582 871 -289 180 0.15 0.41 10,800 650 1,306 -656 240 0.15 0.33 14,400 698 1,741 -1,043 300 0.15 0.28 18,000 740 2,177 -1,436 360 0.15 0.25 21,600 793 2,612 -1,819 480 0.15 0.19 28,800 804 3,483 -2,679 600 0.15 0.16 36,000 846 4,353 -3,507 720 0.15 0.14 43,200 888 5,224 -4,336 1080 0.15 0.11 64,800 1,047 7,836 -6,789 1440 0.15 0.08 86,400 1,066 10,448 -9,382 189 225 BASIN 18 STORAGE PROVIDED : LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : 9-Feb-2018 INFILTRATOR RETENTION CALCULATION Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 0.32 acres Cp :0.90 0.05 acres Cl :0.20 0.37 acres WEIGHTED C:0.81 995 ft2 10 in/hr 0.230 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 0.30 2.75 600 494 138 356 15 0.30 2.25 900 606 207 399 20 0.30 1.75 1,200 628 276 352 30 0.30 1.40 1,800 754 414 340 40 0.30 1.25 2,400 898 553 345 50 0.30 1.05 3,000 943 691 252 60 0.30 0.90 3,600 969 829 140 120 0.30 0.55 7,200 1,185 1,658 -473 180 0.30 0.41 10,800 1,325 2,487 -1,162 240 0.30 0.33 14,400 1,422 3,316 -1,894 300 0.30 0.28 18,000 1,508 4,145 -2,637 360 0.30 0.25 21,600 1,616 4,974 -3,358 480 0.30 0.19 28,800 1,637 6,632 -4,995 600 0.30 0.16 36,000 1,723 8,290 -6,566 720 0.30 0.14 43,200 1,810 9,948 -8,138 1080 0.30 0.11 64,800 2,133 14,922 -12,789 1440 0.30 0.08 86,400 2,172 19,896 -17,724 399 450 BASIN 19 STORAGE PROVIDED : LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : 9-Feb-2018 INFILTRATOR RETENTION CALCULATION Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 0.43 acres Cp :0.90 0.06 acres Cl :0.20 0.49 acres WEIGHTED C:0.81 1278 ft2 10 in/hr 0.296 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 0.40 2.75 600 655 178 478 15 0.40 2.25 900 804 266 538 20 0.40 1.75 1,200 834 355 479 30 0.40 1.40 1,800 1,001 533 468 40 0.40 1.25 2,400 1,191 710 481 50 0.40 1.05 3,000 1,251 888 363 60 0.40 0.90 3,600 1,287 1,065 221 120 0.40 0.55 7,200 1,572 2,130 -558 180 0.40 0.41 10,800 1,758 3,196 -1,437 240 0.40 0.33 14,400 1,887 4,261 -2,374 300 0.40 0.28 18,000 2,001 5,326 -3,325 360 0.40 0.25 21,600 2,144 6,391 -4,247 480 0.40 0.19 28,800 2,173 8,522 -6,349 600 0.40 0.16 36,000 2,287 10,652 -8,365 720 0.40 0.14 43,200 2,402 12,782 -10,381 1080 0.40 0.11 64,800 2,830 19,173 -16,343 1440 0.40 0.08 86,400 2,882 25,565 -22,683 538 585 BASIN 20 STORAGE PROVIDED : LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : 9-Feb-2018 INFILTRATOR RETENTION CALCULATION Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 0.41 acres Cp :0.90 0.06 acres Cl :0.20 0.47 acres WEIGHTED C:0.81 1184 ft2 10 in/hr 0.274 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 0.38 2.75 600 627 164 462 15 0.38 2.25 900 769 247 523 20 0.38 1.75 1,200 798 329 469 30 0.38 1.40 1,800 957 493 464 40 0.38 1.25 2,400 1,140 658 482 50 0.38 1.05 3,000 1,197 822 375 60 0.38 0.90 3,600 1,231 986 244 120 0.38 0.55 7,200 1,504 1,973 -469 180 0.38 0.41 10,800 1,682 2,959 -1,277 240 0.38 0.33 14,400 1,805 3,946 -2,141 300 0.38 0.28 18,000 1,914 4,932 -3,018 360 0.38 0.25 21,600 2,051 5,919 -3,868 480 0.38 0.19 28,800 2,079 7,892 -5,813 600 0.38 0.16 36,000 2,188 9,865 -7,677 720 0.38 0.14 43,200 2,297 11,838 -9,540 1080 0.38 0.11 64,800 2,708 17,756 -15,049 1440 0.38 0.08 86,400 2,757 23,675 -20,918 523 540 BASIN 21 STORAGE PROVIDED : LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : 9-Feb-2018 INFILTRATOR RETENTION CALCULATION Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 0.24 acres Cp :0.90 0.04 acres Cl :0.20 0.28 acres WEIGHTED C:0.79 711 ft2 10 in/hr 0.165 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 0.22 2.75 600 366 99 267 15 0.22 2.25 900 449 148 301 20 0.22 1.75 1,200 466 198 268 30 0.22 1.40 1,800 559 296 262 40 0.22 1.25 2,400 665 395 270 50 0.22 1.05 3,000 698 494 204 60 0.22 0.90 3,600 718 593 126 120 0.22 0.55 7,200 878 1,186 -308 180 0.22 0.41 10,800 982 1,778 -797 240 0.22 0.33 14,400 1,054 2,371 -1,318 300 0.22 0.28 18,000 1,117 2,964 -1,847 360 0.22 0.25 21,600 1,197 3,557 -2,359 480 0.22 0.19 28,800 1,213 4,742 -3,529 600 0.22 0.16 36,000 1,277 5,928 -4,651 720 0.22 0.14 43,200 1,341 7,114 -5,773 1080 0.22 0.11 64,800 1,580 10,670 -9,090 1440 0.22 0.08 86,400 1,609 14,227 -12,618 301 315 BASIN 22 STORAGE PROVIDED : LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : 9-Feb-2018 INFILTRATOR RETENTION CALCULATION Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 0.28 acres Cp :0.90 0.07 acres Cl :0.20 0.35 acres WEIGHTED C:0.76 900 ft2 10 in/hr 0.208 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 0.26 2.75 600 435 125 310 15 0.26 2.25 900 534 188 346 20 0.26 1.75 1,200 554 250 304 30 0.26 1.40 1,800 665 375 289 40 0.26 1.25 2,400 791 500 291 50 0.26 1.05 3,000 831 625 206 60 0.26 0.90 3,600 854 750 104 120 0.26 0.55 7,200 1,044 1,501 -456 180 0.26 0.41 10,800 1,168 2,251 -1,083 240 0.26 0.33 14,400 1,253 3,001 -1,748 300 0.26 0.28 18,000 1,329 3,751 -2,422 360 0.26 0.25 21,600 1,424 4,502 -3,077 480 0.26 0.19 28,800 1,443 6,002 -4,559 600 0.26 0.16 36,000 1,519 7,503 -5,984 720 0.26 0.14 43,200 1,595 9,003 -7,408 1080 0.26 0.11 64,800 1,880 13,505 -11,625 1440 0.26 0.08 86,400 1,914 18,006 -16,092 346 405 Hardscaped Area (Ap): 9-Feb-2018 INFILTRATOR RETENTION CALCULATION BASIN 23 Area Calculations Area Runoff Coefficients LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : STORAGE PROVIDED : Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 0.38 acres Cp :0.90 0.10 acres Cl :0.20 0.48 acres WEIGHTED C:0.76 1184 ft2 10 in/hr 0.274 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 0.36 2.75 600 601 164 437 15 0.36 2.25 900 738 247 491 20 0.36 1.75 1,200 765 329 436 30 0.36 1.40 1,800 918 493 425 40 0.36 1.25 2,400 1,093 658 436 50 0.36 1.05 3,000 1,148 822 326 60 0.36 0.90 3,600 1,181 986 194 120 0.36 0.55 7,200 1,443 1,973 -530 180 0.36 0.41 10,800 1,614 2,959 -1,346 240 0.36 0.33 14,400 1,732 3,946 -2,214 300 0.36 0.28 18,000 1,837 4,932 -3,096 360 0.36 0.25 21,600 1,968 5,919 -3,951 480 0.36 0.19 28,800 1,994 7,892 -5,898 600 0.36 0.16 36,000 2,099 9,865 -7,766 720 0.36 0.14 43,200 2,204 11,838 -9,634 1080 0.36 0.11 64,800 2,597 17,756 -15,159 1440 0.36 0.08 86,400 2,645 23,675 -21,030 491 540 Hardscaped Area (Ap): 9-Feb-2018 INFILTRATOR RETENTION CALCULATION BASIN 24 Area Calculations Area Runoff Coefficients LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : STORAGE PROVIDED : Project : Thomson Farms Project No. : 7835 By : D. Cowley Checked By : J. Ford Date : Sheet : 0.23 acres Cp :0.90 0.06 acres Cl :0.20 0.28 acres WEIGHTED C:0.76 711 ft2 10 in/hr 0.165 cfs Time (min) CA (Acres) Precipitation Intensity (in/hr) Time (sec) Cumulative Runoff (ft3) Allowed Runoff (ft3) Storage (ft3) 10 0.21 2.75 600 354 99 255 15 0.21 2.25 900 434 148 286 20 0.21 1.75 1,200 450 198 253 30 0.21 1.40 1,800 540 296 244 40 0.21 1.25 2,400 643 395 248 50 0.21 1.05 3,000 675 494 181 60 0.21 0.90 3,600 695 593 102 120 0.21 0.55 7,200 849 1,186 -337 180 0.21 0.41 10,800 949 1,778 -829 240 0.21 0.33 14,400 1,019 2,371 -1,352 300 0.21 0.28 18,000 1,081 2,964 -1,883 360 0.21 0.25 21,600 1,158 3,557 -2,399 480 0.21 0.19 28,800 1,173 4,742 -3,569 600 0.21 0.16 36,000 1,235 5,928 -4,693 720 0.21 0.14 43,200 1,297 7,114 -5,817 1080 0.21 0.11 64,800 1,528 10,670 -9,142 1440 0.21 0.08 86,400 1,556 14,227 -12,671 286 315 Hardscaped Area (Ap): 9-Feb-2018 INFILTRATOR RETENTION CALCULATION BASIN 25 Area Calculations Area Runoff Coefficients LANDSCAPE AREA (Al): TOTAL AREA (A): Runoff Calculations Percolation Area Percolation Rate Total Percolation Rate NOTE: 25 Year Storm STORAGE REQUIRED : STORAGE PROVIDED :