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Drainage Reports - 04/09/2007
City of Ft. Collins App �ved Plans Approved By . Date L-i — 9 —0 _? March 30, 2007 Mr. Wes Lamarque City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, CO 80521 RE: Stormwater Pipe Reduction Due to Decrease in Offsite Flow Release Rate Dear Wes: We are pleased to submit for your review and approval this addendum to the Sidehill Filing 2 Final Drainage and Erosion Control Report (May 27, 2005). This addendum addresses the drainage impacts from the revised release rates from the offsite properties to the west of Timberline Road and Sidehill Filing 2. Two drainage reports; Final Drainage and Erosion Control Report for Timberline Center Subdivision, and Final. Drainage and Erosion Control Study for Spring Creek Farms, were reviewed to determine the revised 2-year historic release rates into the Sidehill Filing 2 storm system that initially was sized to receive the 100-year release rates from the offsite properties. Because the offsite release rates have been significantly reduced from the previously approved design rates, it is feasible and practical to redesign the effected Sidehill Filing 2 storm system. The Timberline Center Report states a release rate of 2.1 cfs and 13.3 cfs to Storm 2 and Storm 3, respectively. The Spring Creek Farms Report states a 2-year release rate of 1.1 cfs from Detention Pond 8 into the Sidehill Filing 2 storm system. Therefore, the total release rate into the Sidehill Filing 2 storm system is 16.5 cfs. This reduction in offsite flow enabled 10 pipes on storm profile Line H (sheets 90 & 91) to be reduced in size. The storm pipe from storm manhole 16 to storm manhole 9 are existing pipes and oversized due to the decrease in offsite flow into this storm system. The reduction in pipe size occurs downstream from storm manhole 9 to the flared end section outlet. Also 2 pipes were able to be converted from HERCP to RCP and still maintain adequate cover. The storm profile Line E1 (sheet 88) was revised and the 2 pipes were upsized 0.5 feet but still maintained the approved inverts. The supporting calculations and drainage reports are included with this addendum. JR Engineering has reviewed and concluded that the above -mentioned revisions have been designed with provisions for safe and efficient control of stormwater runoff in a manner that will not adversely affect the stormwater system. X:\3930000.all\3935006\Word\Reports\Drainage Addendum Storm Rev.doc We appreciate your time and consideration in reviewing this submittal. If you have any questions or need additional information please call (970) 491-9888. Prepared by: Mike Malvey Design Engineer /bj'ger arone P.E. C.; 39848 ii ANAL. X:\3930000.all\3935006\Word\Reports\Drainage Addendum Storm Rev.doc M N a STMH-1 1 v N d Scenario: SWMM BASIN.101 100-YR 1 1 I-1A YJTLETTO POND A Title: SideHill Filing 2 and 3 ,• 2007-3-6-revision swmmbasin101-offsite 2yr flows i... 03/08/07 03:09:55 PM JR Engineering © Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA +1-203-755-1666 I 1 Project Engineer: as StormCAD v5.5 [5.5003] Page 1 of 1 1• 19 1 • Profile Scenario: SWMM BASIN 101 100-YR Profile: Outlet to Pond A to STMH-16 Scenario: SWMM BASIN 101 100-YR sm _m sn s s -o =n w '-m mryiO OP " + PPPmm - �OOrm. f6 _'vnm 2 yp c3E0V1 rywa. —wm�n'm- r�v�Pv _ 3g caEE fn DSLL¢ m �a+m" 'gg-ca 2-c ItI-c v �iidl.c E En WLLRI I E� L>>auul w w -c'oem wrvcn "rypNry I ma o.w^- ssa - :, rl$LLCJ! 9q»EE 1 ripe - 31- 9- �2'nCh.-_-Eencnite- �Yc=3EE :nALGLZ J_I 2, - inA C i \ -- E>E o -so c'a�-mev' •\ 131.0011 LPe 36 rich Cancmte ✓ o....opo _oe _$,er 30800H 4a nth Concrete Cs=0012061 Pot O_vp,vT 2^'c ev ac -OcE—_ 12700H 36 ncn Concrete (�S-0002987W _. _.. - _ .- W p O L1'(11L -- _ - _ p-6_- (>g5 =0006850 fU1 cE �05 =rx3 w0iL P,5 267 00 0 62 nth Concrete 71-001 42 nth Cancmte 70900H 421ncn Concrete aS=0. 004725 NI P-4 a S > 0 003944 1Vt 215 00 H 42 nth Concrele `P.3--a5=0.031,21 Nt. - - - Sd 301 42 nth Concrete ` 12 9 S a 0.042206 Po1 4ench- Cancmte as - 0054815 fVl .22-00 .21-00 I -20�00 .19.00 18+00 17-00 -16+00 -15-00 -14a00 -13r00 -12+00 P1 99001 54 nth Concrete as = 000g091 fVt P m0 errs Q.v G1 i6LLLCl�i 494000 ------..P-23--- 4935 00 201.00 h . 36 nth COmCn e —, - 493000 492500 4 920 00 203 00 H 48 ncn Concrele ----------------491500 Eevatun•;f0 P-27 i as • 0 019360 W1 49 10 00 490500 490000 - - - 439500 __- -_ _ -_ ______ _.._ __ __..___. - -. _ __-- _. _.-489000 .11-00 .10-00 .9,00 -8-00 %t00 6.00 -5>00 4+00 340 2.00 .1�00 0-00 Station (H) 1• Title: SideHill Filing 2 and 3 2007-3-6-revision swmmbasin101-offsite 2yr flows i... 03/09/07 07:49:31 AM JR Engineering © Haestad Methods. Inc 37 Brookside Road Waterbury, CT 06708 USA +1-203-755-1666 Project Engineer: es Storm CAD v5.5 [5.5003] Page 1 of 1 Scenario: SWMM BASIN 101 100-YR r1 u JR CUSTOM Label Section Size escriptio Section Shape Material Manning n onstructec Slope (ft/ft) Length (ft) Total System Flow (cfs) Design Capacity (cfs) Rim Elevation (ft) Structure 'Depth (ft) pstrea Invert Elevation (ft) Hydraulic Grade Line In (ft) ownstrea Invert Elevation (ft) Hydrauli Grade Line Out (ft) Average Velocity (ft/s) Headloss oeffcien VelocityTailwater Out (fUs) Elevation (ft) STMH-1 13.30 4,938.22 13.32 4,931.42 4,931.38 0.80 1.88 P-23 36 inch Circula Concre 0.013 0.003731 201.00 13.30 40.74 4,924.90 4,931.38 4,924.15 4,931.30 1.88 1.88 STMH-1 3.30 4,934.39 7.24 4,931.31 4,931.31 0.80 0.67 P-24 30 inch Circula Concre 0.013 0.022523 111.00 3.30 61.55 4,927.15 4,931.31 4,924.65 4,931.30 0.67 0.67 1-25 44.70 4,930.27 10.88 4,930.27 4,930.27 0.00 3.56 P-21 48 inch Circula Concre 0.013 0.003333 6.00 44.70 82.93 4,919.39 4,930.31 4,919.37 4,930.30 3.56 3.56 1-26 24.70 4,930.28 10.84 4,930.28 4,930.28 0.00 1.97 P-20 48 inch Circula Concre 0.013 0.002917 24.00 24.70 77.57 4,919.44 4,930.31 4,919.37 4,930.30 1.97 1.97 STMH-1 16.60 4,937.29 14.14 4,931.30 4:931.28 0.60 1.32 P-27 48 inch Circula Concre 0.013 0,019360 203.00 16.60 199.85 4,923.15 4,931.28 4,919.22 4,931.26 1.32 1.32 STMH-1 69.40 4,930.30 10.93 4,930.58 4,930.30 0.60 5.52 P-22 48 inch Circula Concre •0.013 0.002941 51.00 69.40 77.90 4,919.37 4,931.37 4,919.22 4,931.26 5.52 5.52 STMH-1 86.00 4,931.40 12.18 4,931.26 4,930.75 0.70 6.84 P-11 48 inch Circula Concre 0.013 0.002987 308.00 86.00 78.50 4,919.22 4,930.75 4,918.30 4,929.64 6.84 6.84 STMH-£ 86.00 4,933.02 15.22 4,929.64 4,929.02 0.50 8.94 P-10 42 inch Circula Concre 0,013 0.004725 309.00 86.00 69.15 4,918.30 4,929.02 4,916.84 4,926.76 8.94 8.94 STMH-E 86.00 4,932.71 15.87 4,926.76 4,924.92 0.80 12.17 P-9 36 inch Circula Concre 0.013 0.012061 131.00 86.00 73.25 4,917.34 4,924.92 4,915.76 4,922.74 12.17 12.17 STMH-7 86.00 4,929.92 14.16 4,922.74 4,921.59 0.50 12.17 P-8 36 inch Circula Concre 0.013 0.006850 127.00 86.00 55.20 4,915.76 4,921.59 4,914.89 4,919.48 12.17 12.17 STMH-E 86.00 4,928.06 13.67 4,919.48 4,918.49 0.80 8.94 P-7 42 inch Circula Concre 0.013 0.009355 31.00 86.00 97.30 4,914.39 4,918.49 4,914.10 4,918.26 8.94 8.94 1-3 11.50 4,917.54 8.71 4,917.87 4,917.54 0.50 6.51 P-16 18 inch Circula Concre 0.013 0.010833 24.00 11.50 10.93 4,908.77 4,917.63 4,908.51 4,917.34 6.51 6.51 STMH-E 86.00 4,928.79 14.69 4,918.26 4,916.99 0.80 10.13 P-6 42 inch Circula Concre 0.013 0.014494 267.00 86.00 121.12 4,914.10 4,916.99 4,910.23 4,915.38 13.66 8.94 1-10 23.00 4,917.53 9.02 4,917.34 4,915.23 0.80 13.02 P-15 18 inch Circula Concre 0,013 0.010845 71.00 23.00 10.94 4,908.51 4.915.23 4,907.74 4,911.83 13.02 13.02 STMH-4 86.00 4,919.85 9.62 4,915.38 4,914.63 0.60 8.94 P-5 42 inch Circula Concre 0.013 0.003944 71.00 86.00 63.18 4,910.23 4,014.63 4,909.95 4,914.11 8.94 8.94 STMH-1 23.00 4,915.75 8.51 4,911.83 4,911.33 0.60 7.32 P-14 24 inch Circula Concre 0.013 0.011963 107.00 23.00 24J4 4,907.24 4,911.33 4,905.96 4,910.22 7.32 7.32 1-11 11.00 4,910.09 8.07 4,909.00 4,908.51 0.80 6.22 P-19 18 inch Circula Concre 0.013 0.024444 27.00 11.00 16.42 4,902.02 4,908.51 4,901.36 4,908.22 6.22 6.22 1-12 104.90 4,919.67 9.72 4,914.11 4,913.07 0.50 11.58 P-4 42 inch Circula Concre 0.013 0.031721 215.00 104.90 179.18 4,909.95 4,913.07 4,903.13 4,908.73 19.35 10.90 STMH-1 23.00 4,912.64 6.68 4,910.22 4,909.81 0.50 7.32 P-13 24 inch Circula Concre 0.013 0.012019 104.00 23.00 24.80 4,905.96 4,909.81 4,904.71 4,908.73 7.32 7.32 1-9 22.00 4,910.04 8.68 4,908.22 4,907.01 0.50 12.45 P-18 18 inch Circula Concre 0.013 0.022917 48.00 22.00 15.90 4,901.36 4,907.01 4,900.26 4,904.91 12.45 12.45 STMH-' 127.90 4,910.39 7.26 4,908.73 4,906.43 0.80 13.61 P-3 42 inch Circula Concre 0.013 0.042206 68.00 127.90 206.68 4,903.13 4,906.43 4,900.26 4,904.91 22.62 13.29 WA 15.14 4,901.80 4.14 4,899.89 4,899.89 3.27 P-45 30 inch Circula Concre 0.013 0.008721 305.00 15.14 38.30 4,897.66 4,899.89 4,895.00 4,899.50 7.35 3.08 STMH-2 149.90 4,911.43 12.09 4,904.91 4,902.94 0.80 12.60 P-2 48 inch Circula Concre 0.013 0.054815 81.00 149.90 336.29 4,899.34 4,902.94 4,894.90 4,900.43 25.99 11.93 1-1B 19.14 4,899.50 4.50 4,899.69 4,899.50 0.80 3.90 P-44 30 inch Circula Concre 0.013 0.005556 18.00 19.14 30.57 4,895.00 4,900.47 4,894.90 4,900.43 3.90 3.90 STMH-1 169.04 4,901.00 6.10 4,900.43 4,898.69 0.80 11.83 P-1 54 inch Circula Concre 0.013 0.009091 99.00 169.04 187.49 4,894.90 4,898.69 4,894.00 4,897.83 13.34 11.72 OUTLE" I I I 1 1 1169.041 4,900.00 6.00 4,897.83 4,897,83 1 0.00 4,897.83 9 I Title: SideHill Filing 2 and 3 2007-3-6-revision swmmbasin101-offsite 2yr flows i... 03/09/07 07:49:46 AM JR Engineering m Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA +1-203-755-1666 Project Engineer: es Storm CAD v5.5 [5.5003] Page 1 of 1 • Scenario: SWMM BASIN 102 and 103 100-YR • • INLET FROM POND A �.�%�.;�ed rye .����o✓e� :.�e���f-sue yet �8 OUTLET TO CHANNEL 2 Title: SideHill Filing 2 and 3 x1... \2007-3-6-revision swmmbasin102 and 103.stm 03/30/07 10:39:25 AM JR Engineering Haestad Methods, Inc. 37 Brookside Road ' Waterbury, CT 06708 USA +1-203-755-1666 Project Engineer: es Storm CAD v5.5 15.50031 Page 1 of 1 C] r] I * N I W Z Z U � � cy N 0 �ci:t�0)oc W t-0oit _J M [ Q — >.E� E -4+00 Profile Scenario: SWMM BASIN 102 and 103 100-YR Profile: Pond A Inlet to Channel 2 Outlet 101.00 ft Title: SideHill Filing 2 and 3 x V \2007-3-6-revision swmmbasin102 and 103.stm 03/30/07 10:31:16 AM Scenario: SV\ MM BASIN 102 and 103 100-YR 4=J cl:fO N O � � O N 0 0� �r.Or-O O OO)00Cfl(m I` 00 00 0) d' 00 00 �M»SEE 0 Or,0`�=fO COT-OQ0 O �--�000~0) M���0O0� E P-1 -3+00 -2+00 P 9 -1 +00 93.00 ft 48 inch Concrete 48x76 inch Concrete (§ S = 0.004301 ft/ft @ S = 0.004851 ft/ft Station (ft) 167.00 ft JR Engineering Haestad Methods. Inc 37 Brookside Road Waterbury. CT 06708 USA +1-203-755-1666 Q 0 m O N 00p0-) �0�000 LLo �"t �0�� a J z(n > D g(z0 ,(t,900.00 4,895.00 '(1,890.00 0+00 P-110 48 inch Elevation (ft) Concrete @S=0.004192ft/ft Project Engineer es Storm CAD v5.5 [5 5003] Page 1 of 1 I• Scenario: SWMM BASIN 102 and 103 100-YR El U 10 JR CUSTOM Label Section Size Descriptio Section Shape Material Manning n onstructec Slope (ft/ft) Length (ft) Total System Flow (cfs) Design Capacity (cfs) Rim Elevation (ft) Structure Depth (ft) Upstream Invert Elevation (ft) Hydraulic Grade Line In (ft) ownstrea Invert Elevation ft) Hydraulic Grade Line Out (ft) Average Velocity (ft/s) Headloss oefficien Velocity Out (Ws) Tailwater Elevation (ft) INLET FROM POND 1 97,00 492000 700 4,915,48 4,91548 1978 P-8 30 inch Circula Concre 0.013 0.100328 61 00 9700 129,91 4,913.00 4,915,48 4.906 88 4,91003 2902 1976 1-20 18.80 490630 7,54 4.906,09 4,90609 5.98 P-12 24 inch Circula Ccncre 0.013 0.006000 500 18,80 1752 4,898,76 4,906.09 4.89873 4,906.05 5,98 598 1-18A 18.80 4 906 30 896 4,906 10 490610 3 83 P-11 30 inch Circula Concre 0 013 0005238 21 00 1880 29,68 4,897.34 4,906.10 489723 4,906.05 3.83 383 STMH-22 97.00 4 91564 976 4,910,03 4,908.91 0.60 10.95 P-7 42 inch Circula Concre 0 013 0.029154 331 00 9700 171 78 4.905.88 490891 4.896.23 4,906 05 1840 10.08 STMH-21 13460 4,90650 10 27 490605 4,90301 1 00 1399 P-6 42 inch Circula Concre 0.013 0010000 5400 134.60 10060 489623 4,903.01 489569 490204 1399 1399 STMH-20 134,60 490446 8.77 4,902.04 4,901 15 050 10.71 P-5 48 inch Circula Concre 0.013 0,022247 8900 134.60 21424 4.89569 4,901,15 489371 4,90037 10.71 10.71 STMH-19 13460 490071 7.00 4,900,37 4,89930 0.60 10,71 P-4 48 inch Circula Concre 0.013 0017321 112.00 13460 189.04 4,89371 4,899 30 4.891 77 4,898,32 1071 1071 STMH-18 13460 4,89834 6.57 4,898 32 4897.81 0.50 8 11 P-3 43x68 incl Horizor Concre 0,013 0.004412 3400 134.60 143,50 4.891_77 4,897 81 4,891 62 4,89768 8 11 8.11 INLET FROM POND i 8600 4,90000 7,70 4,897.53 4,897.53 684 P-10 48 inch Circula Concre 0,013 0.004192 167.00 86.00 92.99 4,89230 4,897.53 4,891.60 4.896 93 6,84 6.84 1-1813 154.00 4,89815 6.53 4,397.68 4,89687 0-60 9.28 P-2 43x68 incl Horizor Concre 0 013 0003968 12600 154.00 13609 4.891.62 4,89687 4,891 12 4 89623 928 9 28 STMH-34 8600 4,897 10 550 4,89693 4.896.57 0.50 6.84 P-9 48 inch Circula Concre 0,013 0,004301 93.00 86,00 94.20 4,891.60 4,896.57 4,891.20 4,89623 6,84 6.84 STMH-17 24000 4,896 10 540 489623 4 89474 0.70 11 71 P-1 48x76 incl Horizor Concre 0 013 0 004851 101 00 240.00 199.54 4,890.70 4.894 74 4 890 21 4,89378 11 71 1246 OUTLET TO CHANNE 24000 4,89964 943 4,890.21 4,89021 000 1-27 980 4 925.56 6.79 4.922,07 4,922A7 3 12 P-28 24 inch Circula Concre 0,013 0.005427 199.00 980 16,66 491877 492207 4.917.69 4,921.70 3 12 3.12 1-28 31.20 4,922,90 567 4,921,76 4,921 76 000 6,36 P-30 30 inch Circula Concre 0.013 0.004000 1000 31.20 2594 4,917.23 4,92176 4.917 19 4.921.70 636 636 STMH-32 41 00 4 922.95 6.26 4,921.70 4,921.18 1 00 5,80 P-27 36 inch Circula Concre 0.013 0.006667 21 00 41 00 5446 4,916,69 4,921,18 4,916.55 4,921.10 5.80 5.80 1-23 72.20 4.922 90 6.35 4,921.10 4.920.29 050 1021 P-26 36 inch Circula Concre 0 013 0028022 91.00 72,20 111 65 4,916,55 4,920.29 4 914 00 4,919.22 1021 1021 Outlet #2 to Pond B 72.20 4,919 50 5.50 4,91922 4 91922 0,00 4.919.22 1-35 2900 4 928 98 625 4,928.14 4,928.14 000 5,91 P-21 30 inch Circula Concre 0.013 0,003922 51 00 29.00 2568 4,922 73 4.928 14 4922,53 4,92788 5,91 5.91 1-39 28,20 4,929.22 5.79 4,928.66 4 928.66 000 5 74 P-25 30 inch Circula Concre 0.013 0018095 21 00 28 20 55 17 4,92343 492866 4.923 05 4.928.56 5,74 5.74 1-37 28.20 4,92916 6,07 4,928,61 492861 000 5 74 P-24 30 inch Circula Concre CA13 0.004444 900 28,20 27.34 4,923.09 4,92861 4,923,05 4.928.56 5,74 5,74 STMH-30 29,00 4,929.07 7.04 4.927,88 4,927.73 060 4 10 P-20 36 inch Circula Concre 0.013 0004000 6500 2900 42.18 4.92203 4,92773 4,921 77 4,927.60 4.10 4 10 STMH-31 5640 4.92941 6.86 4.928 56 4,927.97 0,60 7.98 P-23 36 inch Circula Concre 0.013 0015294 51 00 5640 82.48 4,922.55 4,927.97 4,921 77 492760 798 7.98 STMH-29 8540 4.92981 8 54 4,92760 4,926.87 060 8.88 P-19 42 inch Circula Concre 0,013 0003982 11300 8540 63.49 4,921.27 4,926.87 492082 4,926.06 888 8,88 STMH-28 8540 4,93272 11 90 492606 4,925 08 080 8.88 P-54 42 inch Circula Concre 0 013 0009623 5300 8540 98.69 4.92082 4 92508 4.920.31 4,924.69 888 8.88 I-1 C 8540 4,932.50 12 19 492469 4,924 08 050 8.88 P-55 42 inch Circula Concre 0.013 0009542 15300 85.40 98.28 4.92031 4,924.08 4,918.85 4.922,98 8,88 8.88 STMH-27 85.40 4,926.71 8,36 4,922-98 4,922-55 0.60 680 Title: SideHill Filing 2 and 3 x:\._\2007-3-6-revision swmmbasin102 and 103. stm 03/30/07 10 31 30 AM JR Engineering rcn Haestad Methods. Inc 37 Brookside Road Waterbury. CT 06708 USA *1-203-755-1666 Project Engineer. es Storm CAD v5 5 [5 50031 Page 1 of 2 • Scenario: SWMM BASIN 102 and 103 100-YR LA u JR CUSTOM - Label Section Size escriptio Section Shape Material Mannings,-onstructec n Slope (ft/ft) Length (ft) Total System Flow (cfs) Design Capacity (cfs) Rim Elevation (ft) Structure Depth (ft) pstrea Invert Elevation (ft) Hydraulic Grade Line In (ft) ownstrea Invert Elevation (ft) Hydraulic Grade Line Out (ft) Average Velocity (ft/s) Headloss Coefficien elocity Out (fUs) Tailwater Elevation (ft) P-17 48 inch Circula Concre 0.013 0.008957 211.00 85.40 135.94 4.918.35 4,922.55 4,916.46 4,921.80 6.80 6.80 STMH-26 85.40 4,924.46 8.00 4,921.80 4,921.37 0.60 6.80 P-16 48 inch Circula Concre 0.013 0.008971 68.00 85.40 136.04 4,916.46 4,921.37 4,915.85 4,921.13 6.80 6.80 1-32 12.40 4,923.71 5.33 4,920.85 4,920.85 0.00 7.02 P-22 18 inch Circula Concre 0.013 0.005385 13.00 12.40 7.71 4,918.38 4,920.85 4,918.31 4,920.67 7.02 7.02 STMH-25 85.40 4,923.85 8.00 4,921.13 4.920.70 0.60 6.80 P-15 48 inch Circula Concre 0.013 0.004444 9.00 85.40 95.76 4,915.85 4,920.70 4,915.81 4,920.67 6.80 6.80 STMH-24 97.80 4,923.81 8.00 4,920.67 4,920.01 0.70 7.78 P-14 48 inch Circula Concre 0.013 0.008889 72.00 97.80 135.42 4,915.81 4,920.01 4,915.17 4,919.68 7.78 7.78 STMH-23 97.80 4,923.00 8.33 4,919.68 4,919.32 0.50 6.15 P-13 54 inch Circula Concre 0.013 0.015952 42.00 97.80 248.36 4,914.67 4,919.32 4,914.00 4,919.22 6.15 6.15 Outlet#1 to Pond B I I 1 97.80 1 4,919.50 5.50 4,919.22 4,919.22 1 1 0.00 4,919.22 10 Title: SideHill Filing 2 and 3 x:\...\2007-3-6-revision swmmbasin102 and 103.stm 03/30/07 10:31:30 AM JR Engineering © Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA +1-203-755-1666 Project Engineer: es Storm CAD v5.5 (5.5003] Page 2 of 2 OFFSITE DRAINAGE REPORTS MIDI Approved Res O 'ttow Date FORT CO3,S UTMLrvm Drainage and Erosion -` Control Study for: Spring Creek Farms Stantec Fort Collins, CO September 28, 2005 Stantec Consulting, Inc. 209 S. Meldrum Street Fort Collins, CO 80521 Phone: 970-482-5922 Fax: 970-482-6368 • Stantec Consulting Inc. 209 South ibleldrum Street Fort Collins CO 80521-2603 Tel: (970) 482-5922 Fax: (970) 482-6368 stantec.com Stantec September 28, 2005 Mr. Basil Hamdan City of Fort Collins Water Utilities --Storm water 700 Wood Street Fort Collins. Colorado 80521 RE: Drainage and Erosion Control Study for Spring Creek Farms Dear Basil: We are pleased to submit to you, for your review and approval, this Drainage and Erosion Control Study for Spring Creek Farms. All computations within this report have been completed in compliance with the City of Fort Collins Storm Drainage Design Criteria. We appreciate your time and consideration in reviewing this submittal. Please call if you have any questions. Respectfully, Reviewed by: 187010140 r PROJECT DEVELOPMENT PLAN DRAINAGE AND EROSION CONTROL STUDY SPRING CREEK FARMS. FORT COLLINS, COLORADO I. GENERAL LOCATION AND DESCRIPTION 141 A. 'Location MR! Spring Creek Farms is bounded to the east by Timberline Road, to the south by Drake Road, to the west by Union Pacific Railroad and to the south by residential development. The site location can also be described as situated in the southeast quadrant of r Section 19, Township 7 North, Range 68 `Vest of the 6`h P.M., of the City of Fort Collins, Larimer County, Colorado, and comprises approximately 55 acres (see vicinity map in Appendix 1). B. Description of Property The property consists of approximately 55 acres of undeveloped agricultural land. The property is zoned as Low and Medium Density Multi -Use Neighborhood Districts (LVIN and MMN). Light commercial development will be located along the north side of the property. At this time only a portion of the roads for future development are being constructed for the police station site. i The southern portion of the site, approximately 48 acres, generally slopes to the southeast (towards the intersection of Drake Road and Timberline Road) at ` approximately 0.4 to 1.0 percent. The northern portion of the site, approximately 7 4' acres, generally slopes to the northeast at approximately 0.4 to 1.0 percent. II. DRAINAGE BASINS A. Major Basin Description The Spring Creek Farms development lies within the Foothills Basin (See Appendix �i 1 for location). The Spring Creek Farms site generally flows southeast and drains into the North Tributary Storm Drain, which conveys flows to the Fossil Creek ' Reservoir Inlet Ditch, which drains directly to Fossil Creek Reservoir. The reservoir ultimately drains into the Cache la Poudre River. lilt, Currently, an irrigation ditch runs through the northern portion of the site. This ditch is currently being used by the farmland on the immediate east side of Timberline and by the Cargill Corporation. It is a supply ditch that is supplied by the Aurthur Ditch 5 Company but is not owned by the Ditch Company. Based on the approval of the farmer and Cargill, the irrigation ditch will be rerouted via a 2 1 " pipe through the site. The irrigation flows will be routed along the north side of Nancy Gray Avenue and released into a manhole on the west side of Timberline Road that is being constructed by the Timberline Road widening project. Stantec has coordinated with JR Engineering and discussed the invert out of the proposed storm drain from the Spring Creek Farms site. An irrigation easement will be provided for the 21 inch diameter pipe which will take the pipe from where the ditch enters the western side of the site and ties in point on the east side of Timberline Road. Currently a second irrigation drain is located near the center of the site. This drain runs underneath the existing railroad and then turns south. This irrigation ditch has been abandoned and no flows from the west enter the Spring Creek Farms site. B. Sub -basin Description The area encompassed by the proposed Spring Creek Farms development has been divided into 12 sub -basins. These sub -basins are shown on the Drainage Exhibit in the back pocket of this report. Runoff for the proposed site is routed to three on -site detention ponds (see Drainage in the back of the report). One pond is permanent to the future police station and one will be replaced or enlarged at a later date one the properties are developed. III. DRAINAGE DESIGN CRITERIA A. Regulations The Urban Storm Drainage Manual (published by the Urban Drainage and Flood control District — Denver, Colorado) and the City of Fort Collins Storm Drainage Design Criteria have been used to calculate the storm water runoff and design the storm water facilities for the subject site. B. Development Criteria Reference and Constraints The criteria and constraints from the City of Fort Collins will be met. 0 C. Hydrologic Criteria The Rational Method was used in determining surface runoff for the project site. The 2-year and 100-year storm event intensities were used in calculating runoff values. The City of Fort Collins intensity duration frequency curves were used to obtain rainfall data for each storm specified. The FAA method was used for sizing detention ponds. MODS`Wi IM was not used to calculate the Pond Volume because of the limited development at this time. The Rational Method used to calculate historic and developed storm water runoff for all basins. The water quality volumes for both ponds computed using the Water Quality Capture Volume equation from the Urban Storm Drainage Criteria Manual, Volume 3. These calculations and criteria are included in Appendix 4. D. Hydraulic Criteria All hydraulic calculations within this report have been prepared in accordance with the City of Fort Collins Drainage Criteria and are also included in the Appendix. E. Variance No variances are being requested for the Spring Creek Farms Project. IV. DRAINAGE FACILITY DESIGN A. General Concept The site is being developed in phases with different portions being developed at different times. The detention for each development will be sized and provided at the time of each development as it occurs. The infrastructure that is being designed at this time is in anticipation of the Fort Collins Police Facility. When the Police Facility is designed it will enlarge the affected detention pond to accommodate its i improvements. In the future the different developers will also modify and add to the detention ponds. The detention pond north of Nancy Gray Avenue will be modified ` when that area is developed. The temporary detention pond that is at the south end of Joseph Allen Drive will be relocated when future development will occur. The storm drainage outfalls for the site are located at the north and south end of the site. In the north, JR Engineering(the Sidehill Engineer of Record) in 7 conjunction with Interwest Consulting Group (the Timberline Road widening engineer of record) are providing an outlet that is designed for the 100 year historic runoff from the site. In the south the a pipe is being provided that will carry the flows from the northwest corner of Brockman Drive and Timberline Road to the North Tributary Storm Sewer at Drake Rd. and Timberline Rd. Here it will be release into the 42" existing storm drainage system under Drake Road at a maximum rate of 20 cfs. The majority of the developed runoff drains to detention ponds 5 and 8 via storm pipes. The rest of the developed runoff drains to detention pond 2, which is a small temporary detention pond for the runoff from Joseph Allen Drive. Specific Details The Spring Creek Farms site has been broken down into twelve sub -basins. The attributed -runoff from twelve of the basins is routed to the two on -site detention ponds located in the Spring Creek Farms development. SUB -BASIN 1 Sub -basin 1 will remain undeveloped for this site. The storm flow will is from northwest to southeast and drains to an existing storm drain inlet at the northwest comer of East Drake Road and Timberline Road SUB -BASIN 2 Sub -basin 2 is largely undeveloped except for the west half of Joseph Allen Drive. The storm drainage flows north to south. All of Sub -basin 2 will be allowed to infiltrate in the interim condition. The flows will pass through the existing 9' Utility Easement. Flows for Sub -basin 2 equal 1.83 cfs for the 2 year event and 8.41 cfs for the 100 year rainfall event. SUB -BASIN 3 Sub -basin 3 is largely the south half of Brockman Drive with a twenty -foot allowance for the front yards of the adjacent development. The Storm drainage flows to a 5 foot Type R inlet and then to detention pond 5. SUB -BASIN 4 Sub -basin 4 is mostly the east half of Sagebrush Drive and the north half of Brockman Drive with a twenty -foot allowance for runoff from the front yards of the adjacent development. The Storm drainage flows to a 5 foot Type R inlet and then to detention pond 5. SUB -BASIN 5 Sub -basin 5 is the undeveloped area in the center of Brockman Drive, Joseph Allen Drive, Nancy Gray Avenue and Timberline Road. The storm drainage flows to detention pond 5. SUB -BASIN 6 and 7 Sub -basin 6 is the south half of Nancy Gray Avenue with a twenty -foot allowance for the adjacent property. The Storm drainage flows to a 5 foot Type R inlet and then to detention pond 8. SUB -BASIN 8 Sub -basin 8 is north of Nancy Gray Avenue and grades from southwest to northeast. In the future all of sub -basin 8 will drain to detention pond 8. Detention pond 8 outlets to a storm drain pipe that is being constructed with the Sidehill Second Filing. SUB -BASIN 9 -basin 9 comes from Timberline road and flows to the The storm drainage from sub north Type R inlet in Brockman Drive and then to detention pond 5. SUB -BASINS 10 The storm drainage from sub -basins 10 flows from Timberline Road to the 5 ` Type Inlet in Nancy Gray Avenue, then to detention Pond 8. SUB -BASINS 11 The storm drainage from sub -basing 11 flows north to a low point off -site. It is our understanding that this will be discharged directly into the stormsewer provided by the Timberline Road Project. E C. SUB -BASINS 12 The storm drainage fro sub -basin 12 is to account for the future development of the city of Fort Collins police station with sub -basin 5. The storm drainage flows to detention pond 5 DETENTION POND 5 Detention Pond 5 is located at the northwest corner of Brockman Drive and Timberline Road. The discharge rate is 3.7 cfs and has been coordinated with Interwest Consulting Group, who is the engineer of record for the Timberline Road Improvements. Also, the Timberline Road improvements are constructing a storm sewer from Pond 5 to the North Tributary Storm Sewer at Timberline Road and Drake Road. It is our understanding that the storm sewer will be constructed prior to road construction of this project. DETENTION POND 8 Detention Pond 8 is located at the northwest corner of Nancy Gray Avenue and "ro ram^-^.--. ,t -� _ -z .�.,�. Timberline Road The discharge is 11 cfs which is the 2 year historic rateyf his may be modified when furth&f design i"s`done for that area.-'Ifis urideistood that the 100 year historic rate is being designed for. This outlet structure may me modified at a later date when the design is finalized. It is our understanding that the storm sewer will be constructed prior to road construction of this project. Storm Drain Design The storm drains for Spring Creek Farms were designed using UDSewer. V. STORIN WATER QUALITY A. General Concept In general detention ponds 5 and 8 will provide for the water quality capture volumes. 10 B. Specific Details Ponds 5 and 8 will provide a water quality capture volume as follows: Pond WQCV (ac-ft) Water surface elevation 5 .067 4939.70 8 .033 4940.84 Please refer to Appendices calculations., VI. EROSION CONTROL A. General Concept This development lies within the Moderate Rainfall Erodibility Zone and the Moderate Wind Erodibility Zone per the City of Fort Collins zone maps. There should be minimal to no erosion problems after completion of the Spring Creek Farms development. Silt fence will be installed along the north, east and south sides of the site to prevent sediment from leaving the site. Tracking pads will also be placed at entrances/exits to the site. The Erosion Control Plan may be found in Appendix 8. B. Specific Details A silt fence shown on the erosion control exhibit will be installed prior to grading. All disturbed areas not in a roadway or greenbelt area shall have temporary vegetation seed applied within 30 days of initial disturbance. After seeding, a hay or straw mulch shall be applied over the seed at a rate of 1.5 tons/acre minimum, and the mulch shall be adequately anchored, tacked, or crimped into the soil. Those roads that are to be paved as part of the Spring Creek Farms project must have a 1-inch layer of gravel mulch applied at a rate of at least 135 tons/acre immediately after overlot grading is completed. The pavement structure shall be applied within 30 days after the utilities have been installed. If the disturbed areas will not be built on within one growing season, a permanent seed shall be applied. After seeding, a hay -or straw mulch shall be applied over the seed at a minimum rate of 1.5 tons/acre, and the mulch shall be adequately anchored, tacked or crimped into the soil. In the event a portion of the roadway pavement surface and utilities will not be constructed for an extended period of time after 11 �I overlot grading, a temporary vegetation seed and mulch shall also be applied to the lie roadway areas as discussed above. All construction activities must also comply with the State of Colorado permitting process for Storm water Discharges Associated with Construction Activity. A Colorado Department of Health NPDES permit will be obtained so that construction grading can continue within this development. C. Performance Standards �II Spring Creek Farms meets the erosion control performance standards as follows: Per the rainfall performance standard evaluation the PS during construction should be 75.6 and after construction should be 88.9. DuringConstruction the PS is 95.3 and after construction is 97.2, both are well in compliance. The escrow amount required for erosion control is $5,423 based on reseeding the disturbed area. Please note that of the 57.1 acre site, only 5 acres will be disturbed with this project. VII. CONCLUSIONS A. Compliance with Standards All computations that have been completed within this report are in compliance with the City of Fort Collins Erosion Control Reference Manual for Construction Sites and the Storm Drainage Design Criteria Manual B. Drainage Concept The proposed drainage concepts presented in this report and on the construction plans adequately provide for the conveyance of developed on -site runoff to the proposed drainage facilities of the subject site. The combination of the proposed curb and gutter, cross -pans, inlets, and storm pipes will provide for the 2-year and the 100-year developed flows to reach the proposed detention pond at the southeast corner of the site. If, at the time of construction, groundwater is encountered, a Colorado Department of Health Construction Dewatering Permit will be required. 12 •I C. _ Storm water Quality Concept The proposed design has addressed the water quality aspect of storm water runoff. The extended detention basin will provide an opportunity for storm water pollutants to filter out of the storm water runoff before the runoff enters the Foothills Drainage Basin. D. Erosion Control Concept The proposed erosion control concepts adequately provide for the control of wind and rainfall erosion from the Spring Creek Farms development. Through the construction of the proposed erosion control concepts, the City of Fort Collins performance standard shall be met. The proposed erosion control concepts presented in this report and shown on the erosion control plan are in compliance with the City of Fort Collins Erosion Control Criteria. VIII. REFERENCES 1. Storm Drainage Design Criteria and Construction Standards by the City of Fort Collins, Colorado, May 1984, interim revision January 1997. 2. Erosion Control Reference Manual for Construction Sites by the City of Fort Collins, Colorado, January 1991. 13 I.A i i -7 E �o - ® 221yO b mY � YO v U e u c ern ry N I L LL. �i Z Y � I :J 'c m0 C � m a N b a 'A�'8888388888888 88888 88888 a` �oC00000000�e0 ooc66 c6600� I 5¢ ES �88'J'8838'3833b�8 8g8S8 8838g`, 8�—oaoo LL » 0000CCo oCooC CCoo C NLL V e '^ p p pp �j pOO SSOSSSSSSSSSO S`JOSJ SS'J 00' V ; I 4 n " c Q' u a ^at�IN n, anN mho m m`8v o�a�'Sia `3 y o�-o� N eNn w,•�Nd �• m 0{� moy� mmnwttVV m:o� o NNn now a ip�QNmCIm nN mam mNn N ',[ QvnUI O -NOONOO�� m OWN Nip �O ��p pp wO a OgqwJfofNn Cf q m mm NCf VINNmNNnf�l�m Cf mNnNm � N V r�mN t'1nwQNOmNhaO .�QQ NeNaY J E�nw��Ti CwC OiN �j M1 rG GI :A N ]��� P�P.wIN r— °1 o N o o a n O o i0 �'00006CCeooce � eea CdCCC - � N i e O 4 O Q Q y�= O O O 000 J A - oc lR N C N Nf n w Q m O a a n a O m h w Q . m m m Q J'.��inw�gi of oiml: ep Of vl n C.m-� of Oi di M1m w NmQNaM1mw��� m,Qyv ��o' hm m n mm m 5�-NnQNmnaw ��=� N mQa �na m O 3 3 L IT ON I 4 4 F E. 9 E C W < d v ` e � U r o �Y � O d O m 4 7 r �gQoe��888888888888�.ovalnviouo0ccoc000 eo E=:�r-���88888888888 888, ��, "=�rc nln l: m�n00000000000 oco Ii p 93 LL V51m2 P8m`M?"888a'88,88888 88� 88�5�j0m000000000 aM 888' gmp.,zm-Tw88888888885 �.,G00000000000 060 y 5'n v�i ail vgs m rd 'Y=0000000 C_ S 000p'JO^J a a° o g s-SB 8 8 � y � N Rz �N OI P t0 OI e e (O S N tp N O N T m � 9 r �• ?�tGNt[I C I�OlemhmmA eD �Im� m9� 283?888888888 3 � .O.00 rpi a N me yovoOO moo0ruy �P001 PCmOCImNO N mS0m T yI�� 00� �� .V. C1 Pm[ryy (G m M0� Yl d _mOmNP p�9f+Illr (Lr�l�1� 7mC0'1m �N^ m^ pm� Q` mlljO�VfO01pn 'J' If mm m. OWN `Na rvpr Cr C9 m0 m�(�y OY�nlO'I N t7 ill N mf+ O Ml I�mm NmOI R C C1 C m m C 0'D ^t m m m 9 t�l m 9 b Ill N C1 <� InAmv mr� +m r 0o0co0em0eo0 0 600 N r mnd 0co a pmmm min n.-� NteNNN60 mp n�1 mm �J 0 cm0m6.000o0 c ddo 000 SnI nn mR ry S-4 GO1a .Y E N 0 0 0 0 m 0 0 4. ry y pnj E c s"c 0000000000c0 '� mnooNmm _ �E 00000ea00000 � 00oomeo 11: I I I y ''fy'N D � LL U C En O P O 0CI 0 0 0 -q C L yo y+ O 0 0 Cml tV NjA' nSOm••SYN:V �' n SSO <M pC y VNC].m �C100�0NmtT mmm 9 �NNPNOhmP��� � ^1nC m N �40 e b z m No Text ►�' FINAL DRAINAGE AND EROSION CONTROL REPORT .A FOR TIMBERLINE CENTER SUBDIVISION Prepared for: Fleischli Enterprises and Timberline Autoplex Prepared by: North Star Design 700 Automation Drive, Unit I Windsor, Colorado 80550 (970) 686-6939 Revised April 12, 2006 �F -February 21, 2006 r r� i Job Number 114-37 & 114-38 1_ i L, t r, 'J North Star `r. design, in-c. April 12, 2006 Mr. Wes Lemarque . City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, Colorado 80522-0580 RE: Final Drainage and Erosion Control Report for Timberline Center Subdivision Dear Wes, I am pleased to submit for your review, revised this final drainage and erosion control report for the proposed Timberline Center Subdivision. Hydraulic and Hydrologic calculations are per the City of Fort Collins Storm Drainage Manual. The only appreciable change from the previous report is the addition of some off site flows from Sprin; Creek Farms North. The street flows from st to l:this development will be detained in Pond.A du:p t;_aJs simple); the undeveloped portion of the site will be routed over the spillway. I appreciate your time and consideration in reviewing this submittal. Please call if you have any questions. Sincerely, North Star Design, Inca 34288 o: Michael Oberlander, P.E., L.S.I. cus�0,11ALENG<d 700 Automation Drive, Unit I Windsor, Colorado 80�irifl o7n cur• ,,,.,. _ _. --Subdivision (Joseph -Allen -Drive. connection from Nancy Gray -Avenue -and -the -land to the west of the street in this area). 2. DRAINAGE BASINS AND SUB -BASINS 2.1. Major Basin Descriptions i Timberline Center Subdivision is in the Foothills Basin and will drain east through the Sidehill Filing.2 Development and into the Fossil Creek Reservoir Inlet Ditch. The q( Timberline Report identifies the project area as Basin 10 which drains to Pond 10 and • Storm 2 and Basin 11 which drains to Pond 11 and Storm 3. There are other basins from the Timberline Report that contribute to the release to Sidehill. Basin IOA, IOB, 1 I and I IB also will be addressed within this report. - The-Sidehill Development is currently approved and designed to `receive the 100-year existing flows from this area. The development area proposed with the Timberline Center Subdivision is required to release at the 2-year historic rate (0.25 cfs per acre). There are two outfall pipes crossing Timberline Road (Storm 2 and Storm 3 from the Timberline Report). Basins 10, 1OA and 1OB drain to Storm 2 and Basins 11, 11 A, and 11B drain to Storm 3. The Timberline Road project will provide interim detention ponds to reduce flows through the Sidehill Development With the',Timberhne Project, the — nTK� eW detained �elea'se`to Storm 2 is 2:1 cfs ar d1the,detaid f6lease to:.Storm.3'is' 13.3;t fs? The �j total release from the six basins is 15.4 cfs (approximately the 2-year historic off of the developing area and 100-year historic off of the remaining area that will not be developed). These storm pipes were designed for approximately 70 cfs, so the size of the outfall pipes is not in question. JR Engineering has been notified that the Timberline Road project will provide these release rates, and they may redesign future construction phases of Sidehill for this reduced release rate. ffib 2.2. Sub -basin Description V The 6 basins from the Timberline Report (10, 10A, IOB, 11, IIA & 11B) have been f divided into 21 sub -basins for discussion in this report. Basins draining to Pond A & Timberline Storm 3 (release rate 1.5 cfs) Sub -basin 1 is the same as the Timberline Report Basin I IA. This sub basin includes the 2 • Il I II- _— small -area of the Railroad RiI of Way lying west of the proposed Timberline Center. This basin currently drains east to Pond A. This off site flow will drain through the development (over the Pond A spillway) at its present 100-year rate of 1.9 cfs. Sub -basin 2 includes the west portion of the self -storage area and drains north via overland flow to Pond A. Sub -basin 3 includes the north portion of the self -storage area and drains directly to Pond A. Sub -basin 4 and Sub -basin 5 both are in the south-central portion of the self -storage area and drain north to area inlets, Storm A and Pond A. The area inlets are in extremely shallow sumps and will overtop highpoints in the pavement and flow overland to Pond A when the inlets are overwhelmed. -- Sub-basin 6 includes the entry drive of the self -storage complex and drains to an area inlet on Storm A. Sub -basin 7 includes Pond A. Pond A has been designed to detain Basins 2 through 11 to 1.5 cfs and release to Storm F. Storm F is a very deep pipe system that drains south and east in the utility and drainage easement and public streets to the Timberline Storm 3 Outlet Pipe. Basin 1 drains to this pond, but will not be routed through the outlet pipe. Rather, these flows will be directed over the pond spillway into the public right of way. Sub -basin 8 includes the south portion of the self -storage area and the west side of Joseph Allen Drive. All flows will be directed to the street (under the sidewalk). The f street drains to sump inlet and into Storm B. This system drains to Pond A. This basin also includes the west half of Joseph Allen approximately 250' south of the site (on Spring Creek Farms North). This connection has been designed with Spring Creek Farms North, but there is no good way at this time to get the street flows to the Spring Creek Farms North detention pond adjacent to Timberline Road. Pond A has been oversized to take the additional flow from the right of way and detain it. The pond release rate was not raised to account for this additional area; the pond design 100-year water surface is 0.3' higher than the original design, but still well below the spillway. 3 Sub -basin 9 includes the east side of Joseph Allen Drive, a portion of Bear Mountain Drive, and adjacent development area. The streets flow to a sump inlet and into Storm B. This system drains to Pond A. The basin boundary in Bear Mountain Drive is critical to the overall development's design. This highpoint is the location where emergency flows will ultimately drain east in a case where Pond A is completely overwhelmed. All buildings adjacent to and west of this highpoint have been designed to be elevated at least 1 foot above this overtopping elevation (4943.0). Note that the overtopping elevation is considerably higher than the 100-year water surface elevation and the spillway elevation of Pond A. This basin also includes the east half of Joseph Allen approximately 250' south of the site (on Spring Creek Farms North). This connection has been designed with Spring Creek Farms North, but there is no good way at this time to get the street flows to the Spring Creek Farms North detention pond adjacent to Timberline Road. Pond A has been oversized to take the additional flow from the right of way and detain it. The pond release rate was not raised to account for this additional area; the pond design 100-year water surface is 0.3' higher than the original design, but still well below the spillway. Sub -basin 10 includes a portion of the development area northeast of the two public streets. This area will drain to a sump inlet and to Storm B. This system drains to Pond A. Sub -basin 11 includes a portion of the development area southeast of the two public streets. This area will drain to a sump inlet and to Storm B. This system drains to Pond A. All of the inlet elevations are very close to the 100-year WSEL's of the ponds. For the hydraulic calculations, the pond elevation that corresponded to the time of concentration for the basin was used as the tailwater elevation. Sub -basin SCF (Spring Creek Farms) includes the portion of. Spring Creek Farms North lying west of the Joseph Allen Drive connection street. With the construction of the connection street, this 2.2 acres of undeveloped land will flow to the west half of the street, and continue north to Pond A. The Pond A spillway has been oversized to accommodate this undeveloped off site flow. The plans for the street connection include a "blank" 18" RCP crossing at the north end of the street. It is intended that when this 4 basin _develop s, it will_release_to_the_blank_pipe_and.then to_the_Spring Creek Farms_North_—___- Detention Pond adjacent to Timberline Road. No future developed flows should enter Timberline Center unless they are detained to the 2-year historic rate. Basins draining to Pond B & Timberline Storm 2 (release rate 2.5 cfs) Sub -basin 12 includes the southeast portion of the development and Pond B. The majority of the basin drains to Storm D. The design of this system simply accounted for the percentage of the overall basin draining to each of the proposed inlets. • �II Pond B has been designed to detain Basins 12 through 16 to 2.5 cfs and release directly to Timberline Storm 2. This pond will release 0.4 cfs more than is proposed with the Timberline Report; but, because Storm 2 is designed for significantly more flow, this is not problematic. The overall release from -.the. development site is still 0.25 cfs per acre. I' Pond A will overdetain slightly (0.14 cfs per acre for 10.60 acres), and pond B will IIunderdetain slightly (0.43 cfs per acre for 5.77 acres), but the total release of the 16 acres l' will be 4.0 cfs to the Sidehill system. The outlet pipe will have a water quality outlet structure added with this project. Pond B has been designed with an emergency overflow spillway into the proposed Timberline Road. It should be noted that if water flows over the spillway, it will not be directed to the east until it reaches the crown of Timberline Road. All buildings in the development have been designed to be at least 1 foot higher than the overtopping elevation of Timberline Road (4940.5). Sub -basin 13 includes the south side of Bear Mountain Drive. This basin drains to a sump inlet on Storm E and into Pond B. Sub -basin 14 includes the north side of Bear Mountain Drive. This basin drains to a sump inlet on Storm E and into Pond B. Sub -basin 15 is the same as Basin 10A in the Timberline Report. This basin will drain to a sump inlet and pipe to Pond B. The inlet and storm sewer into the pond will be constructed with the Timberline Road project. Sub -basin 16 is the same as Basin IOB in the Timberline Report. This basin will drain 5 i. • 1, ------------(along-with-Basin-l-4)-to-a-sump inlet and pipe to Pond-B- --- Basins draining to Pond C & Timberline Storm 3 (release rate 0.9 cfs) Sub -basin 17 contains the central portion of the development lying north of Bear Mountain Drive. This basin will drain to a sump inlet and Storm C. The system drains to Pond C. Sub -basin 18 includes the proposed car wash and will drain east to Storm C and Pond C. • �I Sub -basin 19 includes a very small portion of the development that will drain through a �? curb cut directly to the north end of Pond C. Sub -basin 20 includes the northwest edge of the development and Pond C. Pond C has been designed to detain Basins 17 through 20 to 0.9 cfs and release directly to Timberline fStorm 3. The outlet pipe, which will be constructed with the Timberline Project, will have a water quality outlet structure added with this Project. Basin 21 drains to this pond, but will not be routed through the outlet pipe. Rather, these flows will be directed over the pond spillway into Timberline Road. Sub -basin 21 is the same as Basin 1113 in the Timberline Report and will be routed through Pond C. 3. DRAINAGE DESIGN CRITERIA 3.1. Regulations it This report was prepared to meet or exceed the "City of Fort Collins Storm Drainage Design Criteria Manual" specifications. Where applicable, the criteria established in the "Urban Storm Drainage Criteria Manual" (UDFCD), 2001, developed by the Denver Regional Council of Governments, has been used. The "Timberline Report" has been ii used to determine release rates to the Sidehill Development. 3.2. Development Criteria Reference and Constraints The runoff from this project will be routed to conform to the Master Drainage Basins, the i 6 •M requirements -on -adjacent, —developing -parcels, and -per the Timberline Report.- 3.3. Hydrologic Criteria Runoff computations were prepared for the 10-year minor and 100-year major storm frequencies utilizing the Rational Method. All hydrologic calculations associated with the basins are included in Appendix B of this report. Additional sub -basins will be added �i with the final drainage design of the project. �i 3.4. Hydraulic Criteria All hydraulic calculations within this report have been prepared in accordance with the City of Fort Collins Drainage Criteria and are included in Appendix C of this report. All storm sewers have been sized based on the 100-year storm (with tailwater based on time __.....of concentration to the receiving ponds). Three detention ponds were designed using the FAA (Rational) iMethod. These calculations are in Appendix D of this report. All ponds release separately and are not in series, so this method is acceptable. 4. DRAINAGE FACILITY DESIGN 4.1. General Concept Proposed flow patterns will match existing patterns and those required by adjacent developments as closely as possible. I' 4.2. Specific Flow Routing There are 22 basins within this project of which 19 will be detained to the 2-year historic rate of 0.25 cfs per acre. All of the flows will be directed to Storm 2 and Storm 3 (Timberline Plans) and through the Sidehill development to FCRID. This is in accordance with the design in the Timberline Report. A summary of the release from the project is as follows: Timberline Report: • 'Total flow to; Storm 2�(8 4 acres) (P,ond l<:0)'s �2rl'Ws > • }Total'flow to Sf 3,'(+17?4 ac s);(jPond 1'l)� 3 F3,crfs 7 oil �i _.— Total_flow to-Sidehill-and.-FCRID =--15.4_cfs i Timberline Center PDP: ,i • Basins 2-11 (10.96 acres) to Storm 3 (Pond A) = 1.5 cfs • Basins 12-16 (5.77 acres) to Storm 2 (Pond B) = 2.5 cfs • Basins 17-20 (3.69 acres) to Storm 3 (Pond C) = 0.9 cfs • Flow over spillway from Basin 1 (2.15 acres) = 1.9 cfs • Flow over spillway from Basin 21 (3.72 acres) = 8.5 cfs oil • Total flow to Sidehill and FCRID = 15.3 cfs 4.3. Drainage Summary Drainage: patterns for this project will meet the requirements of the Master Drainage Basins and will meet the requirements stated in the Timberline Report. 5. EROSION CONTROL �! 5.1 General Concept This site lies within the Moderate Rainfall and Wind Erodibility Zone per the City of Fort (! Collins Zone Maps. The potential exists for silt movement from the site and into the existing drainage areas on the west and north sides of the site. Potential also exists for tracking of mud onto existing streets which could then wash into existing storm systems. The required performance standard for the site is 78%. During construction and after final paving and building construction, this figure has been exceeded with the use of silt fence, inlet protection and by using the detention ponds as sediment traps during construction. zi,7so, The erosion control escrow amount is S19,600. 5.2 Specific Details To limit the amount of silt leaving the site several erosion control measures shall be implemented during construction. Three vehicle tracking pads shall be installed at the locations shown on the plan to control the mud being tracked onto the existing pavement. 8 * -Inlet--protection -will-be --used._on_all-.inlets _throughout_ construc.tion.During_overlot grading, disturbed areas are to be kept in a roughened condition and watered to reduce wind erosion. The detention ponds will all be used as a sediment traps during construction. 6. CONCLUSIONS I6.1. Compliance with Standards All computations that have been completed within this report are in compliance with the Storm Drainage Design Criteria Manual and the Timberline Report. 6.2. Drainage Concept All runoff from the devolvement will be directed to detention ponds and released to the Sidehill development east of Timberline Road and to FCRID. Release rates are in accordance with the Timberline Report' and these release rates are significantly less than the approved design of Sidehill Filing 2 (100-year existing rates). All buildings have been designed to be elevated for protection from the failure of ponds and the overtopping of streets to the east. 7. REFERENCES 1. City of Fort Collins, "Storm Drainage Criteria Manual", (SDCM), dated March, 1956. 2. Urban Drainage and Flood Control District, "Urban Storm Drainage Criteria Manual", Volumes 1 and 2, dated June 2001 and Volume 3, dated September 2001. 3. City of Fort Collins, "Stormwater Basins Map", dated June 1, 2004. 4. North Star Design and Interwest Consulting Group, "100% Design Drainage Report for Interim Timberline Road Widening, Drake to Prospect", dated July 20. 2005. 9 U. U. Z w w W Y Y Q � CL a 0 S H CW G J Z 0 r A - L 7 L 7 Q c c j C L n L n 5 5 = u` Q 0 a i m m m N -pi G c _ Q m U p coo a I n Z J Z Z z MMU w E u u E E E m F == i= I o 0 O O r LC o n U O w O = a a U U N r� 01 P N N N m O m m Q 7 M Q Q C'f P N V N W N O � W m N O m n N n N Q n m O m n w O m O m m m m !� {n W N W n n n 0 N p 5 ?�000aoQoolp rloom000mo?�''�m m V O Yf N N m m P N N Ct 1� m n W T P n O N O U N m o 0 m m 0 0 m 0 0 o N h c o W W 0 0 W m o c n n c c c n c M m h o o h N a a N r o do n d N d .� O V r W m Om m m' m P Q N N OWI p 0 0 vmi CNI 0 o T O M 00 m O O lml O O n n' n N W N LL LL c m O N E z A fJ N .'9. N t'I P N m h W m O � N (�1 P e LL _ = c W m m m LAC, z U b v_ o o- Ti E ;o 0 N v. 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N li Oi I[) Q Oi m t0 � 0 0 0 . m C0 0 m m 0 0 N O N^ m mG ON ¢ t' NNO OC LL E LL Q = a '� a � N l") C IA (O N m m O � N CI C 1A (p N m m N N G C C LL U W 0 N C '• N M C IA m N m m O N t2 C I(l m N m m O N N N N O � N N � a � N O O 0 r LO G e 1 T 7II 1 MATCH LINE SEE 9aEET ] P'em am ® PHA® ®Paw Al IP 1 ! 111 i P 1 - - - - - - e - 1 1 BEAR MOUNTAIN DRIVE L GO 1 i - LOT 14 - -- 1 1i � _�_ �♦ I 1i IIj — ��.�I Law AA I �� ; I ! LOT B I i I 1 � , CE ---- `o J LU I� 1 1 I 1 1 all ! ! z i o - 111111 0 ' o , II _cT 13 LOT 4 N ! 1 No LE: TO 71 BON 4 11, of LOT ENTRfLY-10 FORD C IIIlll�w m I 1 i ° 1 : —4 . i , 1 1 I aF NSIA/gym � r��IR6`TRAK 1 x'av to — { 1 ° LOT B 1 !♦ 1♦ �� � �, I 1 I: CURB i I ' CaL RAT ` LOT 10 1 s tt I — i.TD D.ET I I f = �Ii 1, li LOT uNE I )L P I'�! ►IPA I= IAIII � 1 i i ;_ _ `1 ■! 1 _ B y 1 i _ - Sy III L91 O.I. - 1 ■I .�`.Ci LE FAi MT 1 Dil FORMS Noll .YNS). .GSEPH ALLEN ORINE TO BE CONSTRUCTED Am 1 TIMBERLINE Fit ("No - i all TARNS NORTH). ! STREET WILL l TO n / YffAUNE CENTER FUND A AND BE 1 OI. PLOY FROM THE THE NEST FILL FLOP' DYER PDND P SPILLON NDT T AllSTAY ON SLAY 511E RYE OFHH FURTHER DEVELOPMENT. 4Q+Aft � t rc NANCY GRAY r/ auxnewEl ' 7/ATA rx/sZn, �•aw m bE � ay.lArtST r/ a IxrNHBERUAIe ❑ rD�xNt I Y 0 {i FOLL;3W FOND 3 w /9' IG^ ` C .ro gC cAVIAI w/ J IN14ALAy AFLC)W4 ILA IF 41' - / I. I I / LOT n N I - 1 ;III LOT 12 SPRING CREEK FARMS NORTH SEE LANDSCAPE P_AN FOR PL, l3 RWGNOUT ME SM 1. BE, 91 . 5 FOR L,,,l a PROPOSES BLANKET U?Il OR J IOE. ACCESS AND EMERGENCY 4=5 EASIDIVI . ]. Mls PRpECT REONFEE TIE DOHBIRUaTON OF 1HE'nMLFRa1NE ROAD MDU., - IX'IERIM' PLANS MD THE 'SPRING OIEE( FMMS NORM' PLANE. ROPOSED ,MPROAF]HFNR FOR THESE PUNS ME SIIOM ON NIS PUII A. AS THE HRSF STEP O Ovfl6pT GRADING. DETENTION PONDS A B a C PILL BE CN£R-E%GNAtED AND USED a SEDIMENT TRAPS (FOR THE DIM CONSTRUCTON SE,,MCE). PGAGR SNNL BE O_EANED OF Stal AND BROUGHT TO FINISHED atFillWNG TO INSTA1FICKLE PANS SITE OJITFIG11O1 AND UNDSc4i ]. R,I 10 111 x FOR CIiY O FORT Oil STANDARD GRACING 3 EROSION CCM TRCI NODS S, MY LOT/AREA NOT IMMEDIATELY BJILT ON SHALL BE CEO AND MULCHED. IMEH THE 01 CONSTRUCTION IN W Ma IS r NISHED. IT rLL BE AGETAG© PER THE APPROAED LANDSCAPE It I. SEESKEETER ] FOR Itmm. DRAINAGE aINVMIt .PY -GONSTRucnw sEOUEMCE MD DE Ylm III SJMNMY-TAeLL s� C19 C9E�q� �^ EL9 GO aaCi C o roae m o ila',Rv N(ErAtL� w/ /WaE%uY .DD' av ID GEE /wSiA(iE0 c N 0. NRIOYMo w/ new-«E "Aril- l - T9 �� AYOM.SD t a.alp- � �aaanc• x mBA:rF NIpEYNG ISEFrm MREIRL Alr/ RY@EATJTi IS 1 o 0 1 � Z J V"; Ellin 9URIED RIPRM J (TYPI � i SPRING LTC]( , I FARMS 1l,F, x_xo ���II,�,F�j�[' Ao zo 0 ,,; so SGL: I- = <0' CALL UTILITY NO-IFCA71ON CENIE.R OF WIL PAOO 1.800.922.1987 e�x-�BNSMEss D.n a AIMR✓ h FOR THE MMwrn o�F urcpdiuNO MEYBG UDMES. W Z zz W U U W o Z CIO cr ILL! W �' m W c; f•— Q z ry City of Fort Colllrs. Colorado UTILITY PLAN APPROVAL APPROVE'J: 01, Enq,nw CHEOKE7 SY: Do4 p Al s WGAHwa\r unney Ogee CHECKEO BY: sut, is Jol ORto T CHECMEC BY: PVNP CHECKED BY. . 4 OF 31 Trgfllc Englnw Dote CHECKED BY: dab NO. I • [] • • ♦• logo 00 ♦♦♦♦ _c SZ.- .100 toI tr r Ito II IIII /. III III > 19 21 611 T ST I' polyA \ t00YR WIEL T■� au - A bw � 1 ,, 9b (TI RP 1 L ( P) 3 1 D.bi'J.iS. '.a sTDaM . i I IASZ L 4 54 sIEET 1 iON — RWr-O-YY ,. SEE LWDSCAPE PLAN FM RANPNDs 11aW010UT 111E SnE BASH ORhAA — Aa,ACnYT aaDPmn IqE SE 5 i1AE 1AGTg19 a PED^a4D BLweET UiIl1tY, DaAINAfE, 0. a.9D ID-Y9 Rw07 q)a5lgalT AM A0CF55 AM FNEVGEMCY ACas EAg]lalll A AREA N AaaS _ _ _ _ _ _ - U,SFAIIXT JIIE i Mi4 PTIOECL REOMIES M CWSIRICTIpN O THE •T91aLtllt ROAD - .. - O G Z mt TD,NS 9IOEMN9 - N1FR1N• RNa ANO IIE '$1NP aiD( FAPMS N P. ilgt 09FL•ll(MI PAOPfSD MPRONOiMis M TEST RWAS AEE 9pW al 1N5 RAN. s �„0 .. - 0151Np Id WIETDLwS 1 AS THE FAST STEP IX OAADr aTADNG, `TEEN RON POMOS A 9 t C MLL ff NIp,V.4D Z g270M OVER-DtAVAM ANO USED A9 SEAFNT TRAPS (FOE RQ ENTNE DI2151aUmIDN O NTR1CAO1 E7E1RAMff .-.�— MNgHD TO cartons SFAfHOEL PaalS 9U11 BE aEA]En Or YDMENT AND 10.'01T ro nM51ED GaAOE P m iN5TALLI,F Twg9E PYtI sire aRTtcArCN AND AIll A O�� NAn1F - Pµ 1 ANY LOT//AREA XOL 9RED1AlE1.Y R,9.T Da 9ULL BE £TIDED ANO MUla1®. 911EH ME p1QAl1 AMS1ilC1aM N AX AIEA IS FNTyaD, O \LL 0E N.DRAi:J NIEr `MTELn0I w10A1Z9 OR41A9E tTE P[R 11F APFR0•9D EANOYAPE RAK pO ® v- E161FID 04N..2 PPC a rwL IqR E riF aTT R FOn q]MM srM6ARO 04WIe t ERO90H iD1nn mAP O AlpG 1M As r r Ai AR a .aWBD 9A3)I egAi.R. pNTRO .RA. DRAINAW SUMMARY TABLE o� AIFA no W� rma0 a1D mop 1 L13 0.xL K1 121 67 1.9 x 117 OM ID Ial 9.3 6J 112 ] 0.1a a95 - Jp aD 10 1.7 17 • all 695 i 3.0 10 1.9 4.0 3 DJ] 695 a'0 Sp if S2 1 D.X aT SD SO SD aO 1R 1A it la 7 1A7 61e 1 IN a7f 'i1 1e ua 1 1." aax AD 30 nD 7'a eJ 10 iD 9A to fJl 12a 7,4 m 0.n am R 12 Im sJo aa] a97 on iO aD 30 L9 AS Lf I" a9 18 11 631 % oJ0 an-., 10 1.1 17 a Q91 an o.T 1GU 7�0 all a3 19 Lf a/ 19 0m n l.m aw aD Lf 17.9 11 ae1 are an is IS o124 a9 1 is an 1.15 0 1 110 11 14 111 1y,i 19 12T70 II2La aOSmf q/N9 GYT t QIAYtl1 1 � •.._ HMiG9'D LOT 1 Ir ae.aNn RMve.Ae BALL �I I , STORM C IP i mac an u•a � , � - IP 0 f ¢ E f I w xo I Z I „el .saw, T I 1 ¢ COPD 1 m I` � ♦ IP i I I , 11 I LOT 2, J callart ro , POND a 1�r 5Of OF 1 LOT 1 DE7r-NT1ON POND SUMMARY EK'MO A MM 1 I PDND c 90 lalDlE RErLIiMD OJI AG R. 0.15 AO R. 0.10 Aa R. SElDE90N 1LL1LE Ii0L1EdD 100 Aa R. 1.W Aa R. OE1 AC R. rorAl M319E aEryA9ED ill AG R. 1.19 AG R. 0.95 Aa R. IIC '.DLla2 PRONaD 0.11 A . R. OA7 AL R. 0.11 AL. R. OE1ExT10E 9S]AIE wi0N0ED 1a9 AC R. to Aa FT. 0.1f mrAl la1AE Pa0Np0 1n ACR. 1S1 A FT. on Im YR H911 49NJ b]L1 4110J MAIL RELEASE MTE 14 M 25 65 622 65 aIYAiR7i bf29 bA.3 ball R%SP119MY ,Y tDEa1H m www > W ffTI 1aas.s b1aD bf1Ao CALL UTILITY NOTIFICATION CENTER OF COLORADO 1-800-922.1987 CALL 2-afi 3 DAT N MWAWX i7W YOU x 01 CAR E AR CDR tK mom a INCFRaN'RAO mom UTWES. 40 20 0 fC so SCALE: 1- - W' s K U Q2 �L�iA C E�oW V C O _010 O] Soq ~� 832 L O' =r z Q J d CC LU 0 F L z W Q U � W c Z J � w W m W Q Z Q City of Fort Collins, Colorado cc UTILITY PLAN APPROVAL APPROVED: MY Lv.. out. CHECKED BY: SHEET _. MFV t NCRF.av U111RY Date CHECKED BY: -P C sI�..I- uWh oa. J CHECKED BY: PNb • R.wOm p to CHECKED BY. 3 OF Tr &qh. Dal.