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HomeMy WebLinkAboutDRAINAGE CALCULATIONS - 18-00305 - Approx. 1000 Yellowstone Hwy - Thomson Farms - The Grove Final Plat Phase 1p ENSIGN May 22, 2018 THE STANDARD IN ENE IN EER IND Drainage Narrative Civil Engineering The Grove at Thomson Farms Land Surveying Structural Design Water Design Aerial Technologies 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 the percolation rate was estimated to be 10 inches per hour. In the public road areas, infiltrator rows are proposed to handle runoff. For the apartments a surface retention pond with an infiltration bed is proposed. See the attached storm drain calculations for each of the retention basins and infiltrators. SALT LAKE CITY LAYTON CEDAR CITY TOOELE RICHFIELD 45 West 10000 South, Ste 500 1485 W Hill Field Rd, Ste 204 1870 North Main Street, Ste 104 169 N. Main Street, Unit 1 225 North 100 East Sandy, UT 84070 P 801.255.0529 Layton, UT 84041 Cedar City, UT 84721 Tecate, UT 84074 Richfield, UT 84701 P 801.547.1100 P 435.865.1453 P 435.843.3590 P 435.896.2983 II uuorawE BENCHMARK IlAllll ®eii n.�usrw.aws rows wus TMssxas.swsr uwx romr aure�ascn yrs wer.aass c�n.w,v. cowuraBxxsa ur esu enu..,,,y asmuc,kx �� FUTURi DAWN Project : Thomson Farms _ Project No.: 7835 By: D. Cowley Checked By: J. Ford Date : 22 -May -2018 - Sheet: E N s ' G N THE STANDARD IN ENGINEERING INFILTRATOR RETENTION CALCULATION BASIN 01 Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): ��___dac res Cp : 0.9C LANDSCAPE AREA (AI): �acres Cl 0.20 TOTAL AREA (A): 13.97 acres WEIGHTED C: 0.61 Runoff Calculations Percolation Area ft Percolation Rate in/hr Total Percolation Rate 1.111 cfs Time (min) CA (Acres) Intensity Cumulative I Allowed Runoff Storage (in/hr) Time (sec) Runoff (ft') ) (ft3) (ft')8.52 10 2.75 600 14,061 667 13,39 15 8.52 2.25 900 17,257 1,000 16,257 20 8.52 1.75 1,200 17,896 1,333 16,563 30 8.52 1.40 1,800 21,475 2,000 19,476 40 8.52 1.25 2,400 25,566 2,666 22,900 50 8.52 1.05 3,000 26,844 3,333 23,512 60 8.52 0.90 3,600 27,611 3,999 23,612 120 8.52 0.55 7,200 33,747 7,998 25,749 180 8.52 0.41 10,800 37,735 11,998 25,738 240 8.52 0.33 14,400 40,497 15,997 24,500 300' 8.52 0.28 18,000 42,951 19,996 22,955 360 8.52 0.25 21,600 46,019 23,995 22,024 480 8.52 0.19 28,800, 46,632 31,993 14,639 600 8.52 0.16 36,000 49,087 39,992 9,095 720 8.52 0.14 43,200 51,541 47,990 3,551 1080 8.52 0.11 64,800' 60,745 71,985 -11,240 1440 8.52 0.08 86,400 61,849 95,980 -34,131 NOTE: 25 Year Storm STORAGE REQUIRED : 25,749 STORAGE PROVIDED: " 44.556 Time Project : Thomson Farms Project No.: 7835 By: D. CowleyChecked By: J. Ford '► Date : 22 -May -2018 _ Sheet: �• N $ ' G N THE STANDARD IN ENGINEERING CA 15 20 30 120 180 240 300 INFILTRATOR RETENTION CALCULATION RACInI m Area Calculations Area Runoff Coefficients Hardscaped Area (A=acres Cp: 0.90 LANDSCAPEAREA (Aes CI :1 0.20 TOTAL AREA (A):, 0.43 acres WEIGHTED C:1 0.81 0.34 0.34 0.34 4CUI ft 0.34 600 in/hr 0.34 720 cfs 0.34 1080 0.34 1440, Storage 0.34 NOTE: 25 Year Storm Runup uaTcruanons Tc Intensity (in/hr) Time (sec 2.751 ft 601 2.25 in/hr 901 1.75, cfs 1,201 1.40 1,80( 1251 1.05 Storage 2,40( 3,00( 0.90, 3,60( 0.55 7,20( 0.41 10,80( 0.33 14140( 0.28 18,00( 0.25 21,60( 0.19 28,800 0.16 36,00[ 0.14 43,200 0.11 64,80C 0.08 86,400 Percolation Areal�� ft Percolation Rate in/hr lal Percolation Rate 0.2521 cfs Cumulative Allowed Runoff Storage Runoff (ft) (ft3) (ft3) (' 568 1511 417 698 227 471 I 724 303 421 868 454 414 1,034 605 428 1,085 756329 1,116 908 209 1,364 1,815 -451 1,526 2,723 -1,198 1,637 3,631 -1,994 1,736 4,539 2,802 1,860 5,446 -3,586 1,885 7,262 -5,377 1,985 9,077 -7,093 2,084 10,893 -8,809 2,456 16,339 -13,883 2,500, 21,785 -19,285 STORAGE REQUIRED : 471 STORAGE PROVIDED •: Time Project : Thomson Farms By: D. Cowley ----------- Project No. Date : 22 -May -2018 - Checked By: Sheet: 10 15 20 30 40 50 60 120 180 240. 300 360 480' 600' 720 1080 1440 7835 J. Ford N------------- -----rE N G C IN!NG I N EERING INFILTRATOR RETENTION CALCULATION BASIN 03 Area Calculations LANDSCAPE AREA CA (Acrecl I in NOTE p5 Year 0.26 0.26 0.26 0.26 0.26 0.26 0.26 0.26 0.26 0.26' 0.26 0.26 0.26 0.26 0.26 0.26; 0.26 2.75 2.25 1.75 1.40 1.25 1.05 0.90 0.55 0.41 0.33 0.28 0.25 0.19 0.16 0.14 0.11 0.08 acres acres 0.32; acres Runoff Calculations Percolation Area Percolation Rate Toil Peroolation Rate Time 900 1,200 1,800 2,400 3,000 3,600 7,200 10,800 14,400 18,000 21,600 28,800 36,000 43,200; 64,800 86,400 Cumulative Runoff (ft3i Area Runoff COefficients CP'_ 0.90 CI 0.20 WEIGHTED C: 0.81 ft C - in/hr 0.187 cfs Allowed Runoff Storage -1,471 -2,648 -6,512 -10,265 -14,261, 518 168 537, 224 644 336 767 448 805; 560 829 672 1,013 1,343; 1,132 2,015 1,215 2,686' 1'289, 3,358 1,381, 4,029 1,399 5,372 1,473, 6,715 1,547: 8,058 1,823; 12,088 1,856' 16,117 RAGE REQUIRED :; STOR ROVIDED: -1,471 -2,648 -6,512 -10,265 -14,261, Project: Thomson Farms Project No.: 7835 By: Cowley Checked : J. Ford N S ' G N Date: 22 -May -2018 Sheet et THE STANDARD IN ENGINEERING INFILTRATOR RETENTION CALCULATION BASIN 04 Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): � acres Cp : 0.90 LANDSCAPE AREA (AI): E= acres Cl: 0.20 TOTAL AREA (A): 0.38 acres WEIGHTED C: 0,81 Runoff calculations Percolation Area 0 ft Percolation Rate 0 in/hr Total Percolation Rate 0.230 cfs recipe ation Intensity Cumulative Allowed Runoff Storage Time (min) CA (Acres) (in/hr) Time (sec) Runoff (ft) (ft) (ft) 10 0.31 2.75 600 515 138 377 15 0.31 2.25 900 632 207 425 20 0.31 1.75 1,200 656 276 379 301 0.31 1.40 1,800 787 414 372 40 0.31 1.251 2,400 936 553 384 50 0.31 1.05 3,000 983' 691 292 60 0.31 0.901 3,600 1,011 829 182 120 0.31 0.55 7,200 1,236 1,658 -422 1801 0.31 0.41 10,8001 1,382 2,487 -1,105 240' 0.31 0.33 14,400 1,483 3,316 -1,833 3001 0.31 0.28 18,000 1,573 4,145, -2,572 360 0.31 0.25 21,600 11686 4,974 -3,288 480 0.31 0.19 28,800 1,708 63632 -4,924 600 0.31 0.16 36,000 1,7981 83290 -63492 720 0.31 0.14 43,200 1,888 9,948 -83060 1080' 0.31 0.11 64,800 21225 14,922 -123697 1440 0.31 0.081 86,400 2,2661 193896 -17,630 NOTE: 25 Year Storm STORAGE REQUIRED: 425 STORAGE PROVIDED: 1 45 Time Project: Thomson Farms _ _ Project No.: 7835 By: D. Cowley Checked By : J. For Date : _22 -May -2018 _ Sheet: E N s ' G H THE STANDARD IN FWMW[caiuc INFILTRATOR RETENTION CALCULATION BASIN 05 Area Calculations Area Runoff Coefficients Hardscaped Area(Ap): acres LANDSCAPE AREA (AI): C� acres CID: ' 0.9( _1 ClI : 0.2( TOTAL AREA (A):. 0.44 acres WEIGHTED C:0.7. c Runoff Calculations Percolation Area It Percolation Hatein/hr Total Percolation Rate 0.252 cfs n) CA (Acres) Intensity I I Cumulative I Allowed Runoff) Storage (in/hr) Time (sec) Runoff (ft') (ft3) (ft')10 1 5 0 35 2.75 600 577 151 426 20 0.35 2.25 900 708 227 481 3 0 0.35, 1.75 1,200 734 303 432 40 0.35 1.40 1,800 881 454 427 50 0.35 1.25 2,400 1,049 605 444 60 0.35 1.05 3,000 1,101 756 345 120 0.35 0.90 3,600 1,133 908. 225 180 0.35 0.55 7,200 1,384 1,815 -431 240 0.35 0.41, 10,800 1,548 2,723 -1,175 300' 0.35 0.33 14,400 1,661 3,631., -1,970 360 0.35 0.28 18,000 1,762 4,539 -2,777 480 0.35 0.25 21,600 1,888 5,446., -3,559 600 0.35 0.19, 28,800 1,913 7,262 -5,349 720 0.35 0.16 36,000 2,014. 9,077, -7,064 1080 0.35, 0.14 43,200 2,114 10,893 -8,778 1440, 0.351' 0.11 64,800 2,492 16,339, -13,847 0.35 NOTE. 25 Year StormSTORAGE 0.08 86,400 --EESTORAGE 2,537 21,785 -19,248 REQUIRED 481 PROVIDED:,' 495 Project: Thomson Farms - Project No.: 7835 By: D. Cowley - Checked By : J. Ford Date : 22 -May -2018 - - Sheet _E N s ' G N - - - - - THE STANDARD IN ENGINEMM, INFILTRATOR RETENTION CALCULATION BASIN 06 Area Calculations Hardscaped Area (Ap): C Area Runoff Coefficients LANDSCAPE AREA (Al): acres Cp : 0.90 - - TOTAL AREA (A): acres CI: 0.20 0.52'acres WEIGHTED C: 0.80 Runoff Calculations Percolation Area E:::= it Percolation Rate C- in/hr Total Percolation Rate reclpdahon 0.296 cfs Time(min) ( min CA (Acres) Intensity Cumulative Allowed Runoff Storage 10 (in/hr) Time (sec) Runoff (ft) (ft') 15 0.41 2.75 600 679 178 502 20 0.41 2.25 900 834 266 568 30 0.41 1.75 1,200 865 355 510 40 0.41 1.40 1,800 1,038 533 505 50 50' 0.41 1.25 2,400 1,235 710 525 0.41 1.05 3,000 1,297 888 410 120, 0'41 0.90 3,600 1,334 1,065 269 180' 0.41 0.55 7,200, 1,631 2,130 -500 240 0.41, 0.41 10,800 1,824' 3,196 -1,372 300 0.41 0.33 14,400 1,957 4,261 2,304 360, 0.41 0.28 18,000 2,076 5,326, -3,250 480' 0.41, 0.25' 21,600 2,224 6,391 4,167 600, 0.41 0.19 28,800 2,253 8,522 -6,268 720 0.41 0 .41 0.16 0. 14 36,000 43,200 2,372 10,652 -8,280 1080 0.41 2,491' 12,782 10,292 14401 0.41' 0.11, 64,800 2,935 19,173' -16,238 NOTE: 25 Year Storm 0.08 86,400' 2,989 25,565 -22,576 STORAGE REQUIRED :' 568 31UKAUtVKUVIDED:1 585 Project : Thomson Farms - -----_------- -- ProjectNo.: 7835 BY : D. Cowley Checked B ----------- Date: 22 -May -2018---- ------- Sheet Y� J_Ford - - - ----- ENSIGN THE STANDARD IN ENGINEERING INFILTRATOR RETENTION CALCULATION BASIN 07 Area Calculations Hardscaped:REA1� rea A Area Runoff Coefficients ( p)' acres LANDSCAPE (A: Cp 0.9C acres Cl n �n TOTAI ARCA Tn . 0,57 acres Runoff Calculations Percolation Ares Percolation Rate Total Percolation Rate Time (min) I CA (Acres) I Intensity Cumulative 10 ( ) Time (sec) Runoff (ft') 15 0 44 2.75 600 728 20 0.44 2.25 900 893 30 0.44 1.75 1,200 40 0.44926 1.40 11800 1,111 50 0.44, 1.25 2,400' 60 0.441,323' 1.05 3,000 1,389 120 0.44 0.90 3,600 1,429 180 0.44 0.55 7,200 1,746 240 0.44 0.41 10,800 1,953 300 0.44 0.33 14,400 2,095 360 0.44 0.28 18,000 480 0.442,222 0.25 21,600 2,381. 600 0.44 0.19 28,800 720 0.44,2,413 0.16 36,000 2,540 1080 0.44 0.14 43200 , 2,667 1440 0.44 0.11 64,800 3,143 NOTE: 25 Year Storm 0.44 0.08 86,400 3,200 0 7=7=79in1hr 0.318 cfs Allowed RunOffT Storage 191 286 381, 572 763 953 1,144 2,288 3,432 4,576 5,720 6,864 9,151. 11,439 13,727 20,591 27,454 -1 -2 -4,482 -6,738 -8,899 -11,060 -17,447 -24,254 STORAGE PROVIDED -- 630 Project : Thomson Farms Project No.: 7835 By: D. Cowley Checked By: J. Ford Date: 22 -May -2018 - - _ Sheet : --ENSIGN THE STANDARD IN ENGINEERING INFILTRATOR RETENTION CALCULATION RARIN t)R Area Calculations Area Runoff Coefficients Hardscaped Area , acres Cp :, 0.90 LANDSCAPE AREA (AI): E-1 acres CI : 0.20 TOTAL AREA (A): 0.36 acres WEIGHTED C: 0.78 nunorr caicutauons Percolation Area ft � Percolation Rate � in/hr Total Percolation Rate 0.208'cfs Precipitation Intensity F7,-umulative Allowed Runoff Storage Time (min) CA (Acres) (in/hr) Runoff (ft') (ft3) (ft') 10 0.28 2.75 600 464 125 338 15 0.28 2.25 900 569 188 381 20 0.28 1.75 1,200 590 250 340 30 0.28 1.40 1,800 708 375 333 40 0.28 1.25 2,400 843 500 343 50 0.28, 1.05 3,000 885 625 260 60 0.28 0.90 3,600 910 750 160 120 0.28 0.55 7,200 1,112 1,501, -388 180 0.28 0.41 10,800 1,244 2,251 -1,007 240 0.28 0.33 14,400 1,335 3,001 -1,666 300 0.28 0.28 18,000 1,416 3,751 -2,335 360 0.28 0.25 21,600 1,517 4,502 -2,985 480' 0.28, 0.19 28,800 1,537 6,0021 -4,465 600, 0.28 0.16 36,000 1,618 7,503 -5,885 720 0.28, 0.14 43,200 1,699 9,003 -7,304 1080 1440 0.28 0.11 64,800 2,002 13,505 -11,502 0.28 0.08, 86,400, 2,039 18,006 -15,967 NOTE: 25 Year Storm STORAGE REQUIRED: 381 STORAGE PROVIDED: 405 Project : Thomson Farms Project No.: 7835 By: D. Cowley _ Checked By: J. Ford /'► Date : 22 -May -2018 _ Sheet : _ E N S ' V N THE STANDARD IN ENGINEERING INFILTRATOR RETENTION CALCULATION BASIN 09 Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): acres Cp : 0.90 LANDSCAPE AREA (AI): acres Cl : 0.20 TOTAL AREA (A): 0.63 acres WEIGHTED C: 0.78 Runnff Calculaflnnc Percolation Area � ft Percolation Rate=in/hr Total Percolation Rate 0.361 cls reclplta ron Intensity Cumulative Allowed Runoff Storage Time (min) CA (Acres) (in/hr) Time (sec) Runoff (ft) (ft) (ft') 10' 0.49 2.75 600! 814 2171 597 15 0.49 2.25 900 999 325'- 673 20, 0.49 1.75 1,20011036 4341 602 301 0.49 1.40 1,800 1,243 651 592 40 0.49' 1.25 2,400 1,480 868 612 50 0.49 1.05 3,000 1,554 1,084 469 60' 0.49 0.90 3,600 1,598' 1,301 297 120 0.49 0.55 7,200 1,953 2,603 -650 180 0.49 0.41 10,800 2,184 3,904 -1,720 240 0.49 0.33' 14,400 2,344 5,206 -2,862 300 0.49 0.28 18,000 2,486 6,507 -4,021 360 0.49 0.25 21,600 2,663 7,8081 -5,145 480 0.49 0.19 28,800 2,699 10,411 -7,712 600 0.49 0.16 36,000 2,841 13,014, -10,173 720 0.49 0.14 43,200 2,9831 15,617 -12,634 1080 0.49 0.11 64,800 3,516 23,425 -19,909 1440 0.49 0.081 86,400 3,580 31,233 -27,654 NOTE., 25 Year Storm STORAGEREQUIRED:� 673 STORAGE PROVIDED:1 72Q Project : Thomson Farms Project No.: 7835 By: D. Cowley Checked By: J. Ford Date : 22 -May -2018 Sheet: E N S I G N INFILTRATOR RETENTION CALCULATION BASIN 10 Area Calculations Area Runoff Coefficients Hardscaped Area(Ap): C� acres CP:1 0.90 LANDSCAPE AREA (AI): acres CI: 0,20 TOTAL AREA (A): i 0.06 acres WEIGHTED C: 0.76 Runoff Calculations Percolation Area= ft Percolation Rate E==in/hr Total Percolation Rate 0.055 cfs Precipitation Intensity Cumulative Allowed Runoff Storage Time (min) CA (Acres) (in/hr) Time (sec) Runoff (ft) (ft3) (ft3) 10 0.04 2.751 600 69 331 36 15 0.04 2.251 900 84 50 35 20 0.04 1.75 1,200 88 66 21 30 0.04 1.40 1,800 105 100 6 40 0.04 1.25 2,400 125 1331 -8 50 0.041 1.05 3,000 131 166 -35 601 0.04 0.90 3,6001 135 199 -64 1201 0.04 0.55 7,200- 1651 398 -233 180' 0.04 0.41 10,800' 185- 597 -413 240 0.04 0.33 14,400 198' 797 -598 300 0.04 0.28 18,000 210 996 -785 360 0.04 0.25 21,600 225 1,195 -970 480 0.04 0.19 28,800 228 1,593 -1,365 600 1 0.04 0.16 36,000 240 1,991 -1,751 720 0.04 0.14 43,200 252 2,390 -2,137 1080 0.04 0.11 64,800 297 3,584 -3,287 1440 0.04 0.08 86,400 3031 4,7791 -4,476 NOTE: 25 Year Storm STORAGE REQUIRED: I 36 STORAGE PROVIDED:[ '' 90 Project: Thomson Farms Project No.: 7835 By: D. Cowley Checked By: J. Ford Date: 22 -May -2018 Sheet: _ -ENSIGN THE STANDARD IN ENGINEERING INFILTRATOR RETENTION CALCULATION BASIN 11 Area Calculations Area Runoff Coefficients Hardscaped Area ): (ApE= acres Cp : 0.90 LANDSCAPE AREA (AI): E acres Cl :1 0.20 TOTAL AREA (A): 0.431 acres WEIGHTED C: 0.77 Runnff ralrulafinne Percolation Area ft Percolation Rate in/hr Total Percolation Rate 0.252,cfs reap) a Ion Intensity Cumulative Allowed Runoff Storage Time (min) CA (Acres) (in/hr) Time (sec) Runoff (ft) (ft) (ft') 101 0.33 2.751 600 5481 1511 397 15, 0.33 2.25 900 673 227: 446 20 0.33 1.75 1,200 698 3031 395 30 0.331 1.40 1,800 837 454 383 40 0.33 1.25 2,4001 997 605 391 50 0.33 1.05, 3,000, 1,046 756 290 60 0.33 0.90 3,600 1,076 908 169 120 0.33 0.55 7,200 1,315 1,815' -500 180 0.33 0.41 10,800 1,471 2,723 -1,252 240 0.33 0.33 14,4001 1,579, 3,631 -2,052 300 0.33 0.28 18,0001 1,674 4,539 -2,864 360 0.33 0.25 21,600 1,794 5,446 -3,653 480' 0.33 0.19 28,800 1,818 7,2621 -5,444 600 0.33 0.16 36,000 1,913 9,077 -7,164 720 0.33 0.14 43,200 210091 10,893 -8,884 1080 0.33 0.11 64,8001 2,368 16,339 -13,971 1440, 0.33 0.08 86,400112,411 21,785 -19,374 NOTE., 25 Year Storm STORAGE REQUIRED: 446 STORAGE PROVIDED; 4 Project: Thomson Farms Project No.: 7835 By: D. Cowley Checked By: J. Ford - � � � I Date: 22 -May -2018 Sheet THE STANDARD IN ENGINEERING INFILTRATOR RETENTION CALCULATION BASIN 12 Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): L---1acres Cp :I 0.90 LANDSCAPE AREA (AI): E::= acres Cl :I 0.20 TOTAL AREA (A): 0.22'iacres WEIGHTED C: 0.76 tmnott calculations Percolation Area 0 ft Percolation Rate === in/hr Total Percolation Rate 0.143 cfs reap) a Ion Intensity Cumulative Allowed Runoff Storage Time (min) CA (Acres) (in/hr) Time (sec) Runoff (ft) (ft3) (ft') 10 0.17 2.75 6001 276 86' 191 15 0.17 2.25 900 339 129 211 20 0.17 1.75 1,200 352; 171 180 30 0.17 1.40 1,800 422 257 165 40 0.17 1.25 2,400 503 343 160 50 0.17 1.05 3,000 528 428 99 60 0.17 0.90 3,600 543 514 29 120 0.17 0.55 7,200 663 1,028 -365 180 0.17 0.411 10,800 742 1,542 -800 2401 0.17 0.33 14,400 796 2,056 -1,260 300 0.17 0.28 18,000 844 2,570 -1,726 360 0.17 0.25 21,600 905 -2, 3,084 180 480 0.17 0.19 28,800 917 4,113 -3,196 600 0.17 0.16 36,000 965 5,14 1,, -4,176 720 0.17 0.14 43,200 1,013 6,169 -5,155 1080 0.17 0.11 64,800 1,194 9,253 -8,059 1440 0.17 0.08j 86,400 1,216! 12,338 11,122 NOTE: 25 Year Storm STORAGE REQUIRED: 211 STORAGE PROVIDED: 270 Project: Thomson Farms Project No.: 7835 By: D. Cowley Checked By: J. Ford Date : 22 -May -2018 Sheet: _ E N S I G N THE STANDARD IN ENGINEERING INFILTRATOR RETENTION CALCULATION BASIN 13 Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): acres Cp : 0.90 LANDSCAPE AREA (AI): I � acres CI I TOTAL AREA (A): 0.35 acres I WEIGHTED C: 0.76 Runoff Calculafinns Percolation Area r ft Percolation Ratel- in/hr Total Percolation Rate 0.500 cfs reap) a Ion Intensity Cumulative Allowed Runoff Storage Time (min) CA (Acres) (in/hr) Time (sec) Runoff (ft3) (ft3) (ft) 101 0.26 2.75 6001 4311 3001 131 15 0.26 2.25 900 528, 450 78 20 0.26 1.75 1,200 548 600 -52 30 0.26 1.40 1,800 658 900 -242 40 0.26 1.25 2,400 783 1,2001 -417 50 0.26 1.05 3,000 822 1,500 -678 60 0.26' 0.90 3,600 845 1,800 -955 120, 0.26 0.55 7,200 1,033 3,600 -2,567 180 0.26 0.41 10,800 1,155 514001 -4,245 240 0.26 0.33 14,4001 11240 7,200 -5,960 300 0.26 0.28 18,000 1,315 9,000 -7,685 360 0.26 0.25 21,600 1,409 10,800 -9,391 480 0.26 0.19 28,800 1,428 14,400 -12,972 600 0.26 0.16 36,000 1,503 18,000 16,497 720 0.26 0.14 43,200 1,578 21,600 -20,022 1080 0.26 0.11 64,800 1,860 32,400 -30,540 1440 0.26 0.08 86,400 1,894 43,200 -41,306 NOTE. 25 Year Storm STORAGE REQUIRED: 131 STORAGE PROVIDED :' 405 Project: Thomson Farms Project No.: 7835 By: D. Cowley Checked By: J. Ford /'� Date : 22 -May -2018 Sheet : E N $ ' V N THE STANDARD IN ENGINEERING INFILTRATOR RETENTION CALCULATION BASIN 14 Area Calculations Area Runoff Coefficients Hardscaped Area ): (Apacres Cp : 0.90 LANDSCAPE AREA (AI): acres Cl : 0.20 TOTAL AREA (A): 0.591acres WEIGHTED C: 0,79 Runnff rairulatinns Percolation Area 0 ft Percolation Rate [== in/hr Total Percolation Rate 0.417, cis reclpl a Ion Intensity Cumulative Allowed Runoff Storage Time (min) CA (Acres) (in/hr) I Time (sec) Runoff (ft') (ft) (ft) 10 0.47 2.751 60011 770 2501 520 15 0.47 2.25 900 946 375 571 20 0.47 1.75 1,200 981 500 481 30 0.47 1.40 1,800 1,177 750 427 401 0.47 1.25 2,400 1,401 1,000' 401 50' 0.47 1.05 3,000 1,471 1,250 221 601 0.47 0.90 3,600 1,513 1,500 13 120 0.47 0.55 7,200 1,849 3,000 -1,151 180 0.47 0.41 10,800 2,068 4,500 -2,432 240 0.47 0.33 14,400 2,219 6,000 -3,781 300 0.47 0.28 18,000 2,353 7,500 -5,147 360 0.47 0.25 21,600 2,521 9,000 -6,479 480 0.47 0.19 28,8001 2,555 12,000 -9,445 600 0.47 0.16 36,0001 2,690 15,000 -12,310 7200.47 0.14 43 200 2,824 18,000 -15,176 1080 0.47 0.11 64,8001 3,328 27,000 -23,672 1440 0.47 0.08 86,400] 3,389 36,000 -32,611 NOTE: 25 Year Storm STORAGE REQUIRED: 571 STORAGE PROVIDED: 615 Project: Thomson Farms Project No.: 7835 By: D. Cowley Checked By: J. Ford_ _� � �' Date: 22 -May -2018 Sheet: INFILTRATOR RETENTION CALCULATION BASIN 15 Area Calculations Area Runoff Coefficients Hardscaped Area (Ap): Ir�� acres Cp : 0.90 LANDSCAPE AREA (Al): u acres Cl: 0.20 TOTAL AREA (A):', 0.39iacres WEIGHTED C: 0,81 Runoff Calculations Percolation Area ft Percolation Rate =inlhr Total Percolation Rate 0278 cfs Precipitation Intensity Cumulative Allowed Runoff Storage Time (min) CA (Acres) (in/hr) Time (sec) Runoff (ft) (ft) (ft) 10 0.32 2.75 600 522 1671 355 15 0.32 2.25 900 641 2501 391 20 0.32 1.75 1,200 664 3331 331 30; 0.32 1.40 1,800 797 5001 297 401 0.32 1.25 2,400 949 667 282 50 0.32 1.05 3,000 996 833 163 60 0.32 0.90 3,600 1,025 1,000 25 120 0.32 0.55 7,200 1,253 2,000 -747 180 0.32 0.41 10,800 11401 3,000 -1,599 240 0.32 0.33 14,4001 1,503 4,000 -2,497 300 0.32 0.28 18,000 1,594 5,000 -3,406 360 0.32 0.25 21,6001 1,708 6,000 -4,292 480 0.32 0.19 28,800' 1,731 8,000 -6,269 600, 0.32 0.16 36,000 1,822 10,000 -8,178 720 0.32 0.14 43,200 1,913 12,000 -10,087 1080 0.32 0.11 64,800 2,255 18,000 15,745 1440 0.32 0.08 86,400 2,296 24,000 -21,704 NOTE: 25 Year Storm STORAGE REQUIRED: 391 STORAGE PROVIDED: r Project: Thomson Farms Project No.: 7835 By: D. Cowley Checked By: J. Ford Date : 22 -May -2018 Sheet: E N S I G N THE STANDARD IN ENGINEERING INFILTRATOR RETENTION CALCULATION BASIN 16 Area Calculations Hardscaped Area (Ap): F - LANDSCAPE AREA (AI): r Area Runoff Coefficients Cp :0.90 Cl :020 TOTAL AREA (A):! 0.41 jacres I WEIGHTED Percolation Area � ft Percolation Rate��in/hr Total Percolation Rate 0.252 cfs Precipitation Intensity Cumulative Allowed Runoff Storage Time (min) CA (Acres) (in/hr) Time (sec) Runoff (ft') (ft3) (ft') 10' 0.34 2.75 600 5571 151 406 15 0.34 2.25 900 684 227 457 201 0.34 1.75 1,200 709 303 407 30 0.34 1.40 1,800 851 454 397 40 0.34 1.25 2,4001 1,013 605 408 50 0.34 1.05 3,000 1,064 756 307 60 0.34 0.90 3,600 1,094 908 186 120 0.34 0.55 7,200 1,3 37 1,815 -478 180 0.34 0.411 ' 10,800 1,495 2,723 -1,228 240 0.34 0.33 14,400 1,605 3,631 -2,026 300 0.34 0.28 18,000 1,702 4,539 -2,837 360 0.34 0.25 21,600 1,823 5,446, -3,623 480 0.34 0.191 28,800 1,848' 7,262 -5,414 600 0.34 0.16 36,000 1,945 9,077 -7,132 720 0.34 0.14 43,2001 2,0421 10,893 -8,851 1080 0.34 0.11 64,800 2,407 16,339 -13,932 1440 0.34 0.08 86,400 2,451 21,785 -19,335 NOTE: 25 Year Storm STORAGE REQUIRED: 457 STORAGE PROVIDED ..;T,,,,y„'¢,5