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Detention Timing Analysis Southwest Crossing & Water System Analysis
Kimley-Horn and Associates, Inc. D~·l1lf ~ ·d-J-f)'/t 1: 1c5 ~\4 July 20, 2009 Alan Gibbs City of College Station 1101 Texas Aves College Station, TX 77840 RE : Detention Timing Analysis Southwest Crossing Dear Mr. Gibbs: The purpose of this letter is to address th e City's request made on June 17, 2009 asking for additional stud y of the peak flow timing at the downstream confluences with Tributaries A and B with the main stem of Bee Creek. KHA has utilized the hydrologic modeling provided to KHA by the City of College Station on July 17, 2009 as a basis for this add itional study. KHA made th e following mod ification s to the modeling to develop an existing condtion and proposed condition mod el for the subjec t tract. • Basin "BEE BN 1" was modified in existing condi tions to break out the subject site (Basin "Site"). For the subject site, impervious percentage was set to 0% and th e lag time was set to be consistent with the previous timi ng study . All other values were kept consistent with the original mode l. • Basin "S ite" was modified to generate a proposed condition mode l. The impervious pe rcentage was set to 37% and lag time was set to be consistent with the previou s timing study. No oth er values were cha nged . • The control specifications in both model s was modified to ru n with 1 minute intervals. This change was made due to the lower lag times for the subject site . The models were run in th e 10, 50 and 100 year events. The table below indicates the peak fl ow at the two con fluences. Junction-6 is the co nfluence of Bee Creek and Tribut ary B, and Juncti on-8 is the confluence of Bee Creek and Tributary A. In all cases , th e peak flow does not exceed the existing condition peak flow . • TEL 979 846 8401 FAX 979 846 8450 • Suite 105 111 University Drive East College Station, Texas 77840 Kimley-Horn and Associates, Inc. T 'b A t B C k n utary a ee ree Existing Proposed Difference Stonn ( cfs) (cfs) ( cfs) (yr) Junc-8 J unc-8 Ju nc-8 IO 3,790 3,790 0 50 5,3 16 5.3 1 s -I 100 5,724 5,723 -I T .b t B t B C k n u ary a ee ree Storm Existing Proposed DifTerence (yr) (cfs) (cfs) ( cfs) Junc-6 Junc-6 Junc-8· IO 2,658 2,657 -I so 3,622 3,620 -2 IOO 3,793 3,7 9 I -2 Copies of the modeling output and the hydrographs at th e two subject locations are attached to this letter. Sincerely, Kimley-Horn and Associa tes, Inc. J Chris Harris, P.E. Associate Project: Simulation Run : 10-Year Existing Start of Run: 01 Jan1983, 00:00 End of Run: 04Jan1983, 02 :45 Compute Time: 20Jul2009, 10:49:47 Volume Units: IN Basin Model: Existing Meteorologic Model: 10-Year Control Specifi cations: Control Hydrol ogic Drainage Area Peak Di scharge Time of Peak Volume El ement (Ml2 ) (CFS) (IN) 180 0.6600000 522 01Jan1 983, 16:47 5.80 190 1.7800000 1647 01Jan1 983, 16:24 6.27 290 0.1200000 11 5 01Jan1983, 16:32 6.39 310 1.0500000 764 01Jan1 983, 16:44 5.23 BATE XS 1.7800000 1651 01 Ja n1 983, 16:14 6.27 BEBN2A 0.1800000 163 01Jan1 983, 16:29 6.25 BEBN2B 0.1200000 122 01J an1983, 16:18 6.39 BEBN2C 0.2200000 263 01J an1 983, 16:04 6.66 BEBN2D 0.1700000 154 01Jan1 983, 16:29 6.25 BEBN2E 0.1200000 124 01J an1 983, 16:16 6.42 BEE1 1.0000000 578 01J an1 983, 17:34 5.83 BEE2 1.22 00000 922 01Jan1 983, 16:48 5.75 BEE3 0.8400000 364 01Jan1 983, 18:26 4.98 BEEA1 0.6600000 522 01Jan1 983, 16:42 5.80 BEEA2 1.1200000 1258 01Jan1 983, 16:09 6.55 BEEA3 0.4600000 248 01Jan1 983, 17:40 5.25 BEEBN1 1.02 08000 699 01Jan1 983, 16:59 5.46 BEEBS 1.0500000 764 01Jan1 983, 16:44 5.23 BEEBS1 0.5800000 466 01Ja n1 983, 16:36 5.3 1 BEEBS2 0.4700000 315 01Jan1 983, 16:59 5.12 BE EBS3 0.5200000 325 01Jan1983, 17:11 5.17 FM281 8 2.7799562 1909 01Jan1 983, 16:52 5.37 Junction-1 1.5700000 1068 01Jan1 983, 16:51 5.21 Junction-2 0.2900000 269 01Jan1 983 , 16:30 6.31 Junction-3 3.0699562 2026 01Jan1 983, 17:07 5.46 Page 1 Hydrologic Drainage Area Peak Discharge Time of Peak Volume Element (Ml2) (CFS) (IN) Juncti on-4 3.1899562 2107 01Jan1983, 17:04 5.49 Junction-5 3.4099562 2227 01Jan1983, 17:06 5.57 Juncti on-6 4.4099562 2658 ~--fJi ,,;~·-1 i:F·~ °i'~; 01Jan1 983, 17:18 5.63 ~ ~ ~ll~. Junction-7 5.6 299562 2796 01Jan1983, 18:21 5.65 Juncti on-8 7.869956 2 3790 l",(';,M .;:;tt't 01Jan1 983, 17:47 5.76 ~f:11 M it Junction-9 8.7099562 3836 01Jan1983, 19:13 5.68 RCH 1 7.8699562 3509 01Jan1983, 19:18 5.75 RCH 2 4.4099562 2302 01Jan1983 , 18:36 5.62 RCH 3 4.4099562 2652 01Jan1983, 17:24 5.62 RCH 4 1.0000000 532 01Jan1983, 18:07 5.82 RCH 6 3.1 899562 2103 01Jan1983, 17:12 5.49 RCH 7 2.7799562 1817 01Jan1983, 17:14 5.37 Site 0.0091562 17 '' 01Jan1983, 15:39 6.66 TRIBA 2.2400000 1809 01Jan1983, 16:27 6.06 Page 2 Project: Simulation Run: 10-Year Proposed Start of Run: 01 Jan1983, 00:00 End of Run: 04Jan1983, 02:45 Compute Ti me: 20Jul2009, 10:24:24 Vol ume Units: IN Basin Model: Proposed Meteorologic Model: 10-Year Control Specifi cations: Control Hydrologic Drain age Area Peak Discharge Time of Peak Volume El ement (Ml2) (CFS) (IN) 180 0.6600000 522 01Jan1 983, 16:47 5.80 190 1.7800000 1647 01Jan1 983, 16:24 6.27 290 0.1200000 11 5 01Jan1 983, 16:32 6.39 310 1.0500000 764 01Jan1 983, 16:44 5.23 BATEXS 1.7800000 165 1 01Jan1 983, 16: 14 6.27 BEBN2A 0.1 800000 163 01Jan1 983, 16:29 6.25 BEBN2B 0.1200000 122 01Jan1 983, 16:18 6.39 BEBN2C 0.2200000 263 01Jan1 983, 16:04 6.66 BEBN2D 0.1 700000 154 01Jan1983, 16:29 6.25 BEBN2E 0.1200000 124 01Jan1983, 16:16 6.42 BEE1 1.0 000000 578 01Jan1 983, 17:34 5.83 BEE 2 1.2200000 922 01Jan1 983, 16:48 5.75 BEE3 0.8400000 364 01Jan1 983, 18:26 4.98 BEEA1 0.6600000 522 01Jan1983, 16:42 5.80 BEEA2 1.1200000 1258 01Jan1 983, 16:09 6.55 BEEA3 0.4600000 248 01Jan1 983, 17:40 5.25 BEEBN1 1.0208000 699 01Jan1 983, 16:59 5.46 BEE BS 1.05 00000 764 01Jan1 983, 16:44 5.23 BEEBS1 0.5800000 466 01Ja n1 983, 16:36 5.31 BEEBS2 0.4700000 315 01Jan1 983, 16:59 5.12 BEEBS3 0.5200000 325 01Jan1 983, 17:1 1 5.17 FM28 18 2.7799562 1909 01Jan 1983, 16:52 5.38 Junction-1 1.5700000 1068 01Jan1 983, 16:51 5.21 Junction-2 0.2900000 269 01Jan1 983, 16:30 6.31 Junction-3 3.069 9562 2025 01Jan1 983, 17:07 5.46 Page 1 Hydrologic Drainage Area Peak Discharge Time of Peak Volume Element (Ml2) (CFS) (IN) Juncti on-4 3.1899562 21 06 01Jan1 983, 17:04 5.50 Junction-5 3.4099562 2225 01Jan1 983, 17:06 5.57 Junction-6 4.4099562 2657 :f • " 01Jan1 983, 17:18 5.63 ' '. Junction-7 5.6299562 2796 01Jan1 983, 18:2 1 5.65 ' Junction-8 7.86 99562 3790 ~' 01Jan1 983, 17:47 5.77 Junction-9 8.7099562 3836 01Jan1 983, 19:13 5.68 RCH 1 7.8699562 3509 01Jan1 983, 19:18 5.75 RCH 2 4.4099562 2301 01Jan1 983, 18:36 5.62 RCH 3 4.4099562 2652 01Jan1 983, 17:24 5.63 RCH 4 1.0000000 532 01Jan1 983, 18:07 5.82 RCH 6 3.1 899562 21 02 01Jan1 983, 17:12 5.50 RCH 7 2.7799562 1816 01Jan1 983 , 17:14 5.38 Site 0.0091 562 24 01Jan1 983 , 15:30 8.91 TRIBA 2.2400000 1809 01Jan1 983 , 16:27 6.06 Page 2 Project: Simulation Run: 50-Year Existing Start of Run: 01 Jan1983, 00:00 End of Run: 04Jan1983, 02:45 Compute Time: 20Jul2009, 10:49:57 Volume Units: IN Basin Model: Existing Meteorologic Model: 50-Year Control Specifications: Control Hydrologic Drainage Area Peak Di scharge Time of Peak Volume El ement (Ml2) (CFS) (IN) 180 0.66 00000 71 7 01J an1 983, 16:46 8.34 190 1.7800 000 2271 01Jan1 983, 16:24 8.91 290 0.1200000 156 01J an1 983, 16:33 9.03 310 1.0500000 1058 01Jan1 983, 16:44 7.67 BATEXS 1.7800000 2278 01J an1 983, 16:15 8.91 BEBN2A 0.1800000 222 01J an1 983, 16:29 8.85 BEBN2B 0.1200000 166 01Jan1 983, 16:18 9.03 BEBN2C 0.2200000 359 01J an1 983, 16:04 9.39 BEBN2D 0.1700000 211 01J an1 983, 16:29 8.85 BEBN2E 0.1200000 170 01J an1 983, 16:16 9.07 BEE1 1.0000000 795 01Jan1 983, 17:34 8.32 BEE2 1.2200000 1267 01J an1983, 16:48 8.30 BEE3 0.8400000 509 01J an1 983, 18:26 7.31 BEEA1 0.6600000 71 8 01J an1 983, 16:42 8.34 BEEA2 1.1200000 1716 01 Ja n1 983, 16:09 9.25 BEEA3 0.4600000 344 01Jan1 983, 17:40 7.65 BEEBN1 1.020 8000 965 01Jan1 983, 17:00 7.94 BEE BS 1.0500000 105 8 01Jan1 983, 16:44 7.67 BEEBS1 0.5800000 644 01J an1 983, 16:36 7.76 BEEBS2 0.4700000 437 01Jan1 983, 17:00 7.56 BEEBS3 0.5200000 450 01Jan1 983, 17:11 7.60 FM2818 2.7799562 2641 01Jan1 983, 16:52 7.84 Junction-1 1.5700000 1480 01Jan1 983, 16:51 7.65 Junction-2 0.2900000 366 01Jan1 983, 16:30 8.92 Junction-3 3.0699562 27 37 01Jan1983, 17:12 7.94 Page 1 Hydrologic Drainage Area Peak Discharge Time of Peak Volume Element (Ml2) (CFS) (IN) Junction-4 3.1899562 2843 01Jan1 983, 17:09 7.98 Junction-5 3.4099562 2998 01Jan1 983, 17:12 8.07 <'t.li~#J ": .•.. < ! Junction-6 4.4099562 ; 3622 i 01Jan1983, 17:23 8.13 f Junction-? 5.6299562 3926 01Jan1 983, 18:22 8.15 < Juncti on-8 7.8699562 I 5316 ,...,,,~ 01Jan1 983, 17:41 8.30 -l Juncti on-9 8.7099562 5553 01Jan1 983, 18:55 8.18 RCH 1 7.8699562 5068 01Jan1 983, 19:00 8.28 RCH 2 4.4099562 3246 01Jan1 983, 18:39 8.11 RCH 3 4.4099562 3599 01Jan1 983, 17:33 8.1 3 RCH 4 1.0000000 735 01Jan1 983, 18:07 8.31 RCH 6 3.1 899562 2837 01Jan1 983, 17:17 7.98 RCH 7 2.7799562 2461 01Jan1 983, 17:18 7.84 I' Si te 0.0091562 23 01Jan1983, 15:39 9.63 ' TRIBA 2.2400000 2498 01Jan1 983, 16:27 8.65 Page 2 Project: Simulation Run : 50-Year Proposed Start of Run: 01 Jan1983, 00:00 End of Run: 04Jan1983, 02:45 Compute Time: 20Jul2009, 10:24:42 Volume Units: IN Basin Model: Proposed Meteorologic Model: 50-Year Control Specifications: Control Hydrologic Drainage Area Peak Discharge Time of Peak Volume Element (Ml2) (CFS) (IN) 180 0.6600000 717 01Jan1983, 16:46 8.34 190 1.7800000 2271 01Jan1983, 16:24 8.91 290 0.1200000 156 01 Jan1983, 16:33 9.03 310 1.0500000 1058 01Jan1983, 16:44 7.67 BATEXS 1.7800000 2278 01Jan1983, 16:15 8.91 BEBN2A 0.1800000 222 01Jan1 983, 16:29 8.85 BEBN2B 0.1200000 166 01Jan1983, 16:18 9.03 BEBN2C 0.2200000 359 01Jan1983, 16:04 9.39 BEBN2D 0.1700000 211 01Jan1983, 16:29 8.85 BEBN2E 0.1200000 170 01Jan1983 , 16:16 9.07 BEE1 1.0000000 795 01Jan1983, 17:34 8.32 BEE2 1.2200000 1267 01Jan1983, 16:48 8.30 BEE3 0.8400000 509 01Jan1983 , 18:26 7.31 BEEA1 0.6600000 718 01Jan1983, 16:42 8.34 BEEA2 1.1200000 171 6 01Jan1983, 16:09 9.25 BEEA3 0.4600000 344 01Jan1983, 17:40 7.65 BEEBN1 1.0208000 965 01Jan1983, 17:00 7.94 BEE BS 1.0500000 1058 01Jan1983, 16:44 7.67 BEEBS1 0.5800000 644 01Jan1983, 16:36 7.76 BEEBS2 0.4700000 437 01Jan1 983, 17:00 7.56 BEEBS3 0.5200000 450 01Jan1983, 17:11 7.60 FM2818 2.7799562 2640 01Jan1983, 16:52 7.85 Junction-1 1.5700000 1480 01 Jan1983, 16:51 7.65 Junction-2 0.2900000 366 01Jan1983, 16:30 8.92 Junction-3 3.0699562 2736 01Jan1983, 17:12 7.95 Page 1 Hydrologic Drainage Area Peak Discharge Time of Peak Volume Element (Ml2) (CFS) (IN ) Ju ncti on-4 3.1899562 2842 01Jan1983, 17:09 7.99 Junction-5 3.4099562 2996 01Jan1 983, 17:12 8.08 Junction-6 4.4099562 3620 0 1Jan1 983, 17:23 8.1 3 Junction-? 5.6299562 3925 01Jan1983, 18:22 8.16 .,. . Junction-8 7.8699562 5315 01Jan1 983, 17:41 8.30 Junction-9 8.7099562 5553 01Jan1 983, 18:55 8.19 RCH 1 7.8699562 5068 01Jan1 983, 19:00 8.28 RCH 2 4.4099562 3245 01 Jan1 983, 18:39 8.12 RCH 3 4.4099562 3597 01Jan1 983, 17:33 8.13 RCH 4 1.0000000 735 01Jan1983, 18:07 8.31 RCH 6 3.1899562 2836 01 Jan1 983, 17: 17 7.99 RCH 7 2.7799562 2460 01Jan1 983, 17:1 8 7.85 Site 0.0091562 32 '-01 Jan1983, 15:30 12.45 - TRIBA 2.2400000 2498 01Jan1983, 16:27 8.65 Page 2 Project: Simulation Run: 100-Year Existing Start of Run: 01Jan1983, 00:00 End of Run: 04Jan1983, 02:45 Compute Time: 20Jul2009, 10:49:38 Volume Units: IN Basin Model: Existing Meteorologic Model: 100-Year Control Specifications: Control Hydrologic Drainage Area Peak Discharge Time of Peak Volume Element (Ml2) (CFS) (IN) 180 0.6600000 730 01Jan1983, 16:49 9.27 190 1.7800000 2275 01Jan1983, 16 :28 9.78 290 0.1200000 157 01Jan1983, 16:36 9.90 310 1.0500000 1083 01Jan1983, 16:47 8.54 BATEXS 1.7800000 2280 01Jan1983, 16:19 9.78 BEBN2A 0.1800000 224 01Jan1983, 16 :31 9.77 BEBN2B 0.1200000 165 01Jan1983, 16:20 9.90 BEBN2C 0.2200000 348 01Jan1983, 16:07 10.20 BEBN2D 0.1700000 212 01Jan1983, 16:31 9.78 BEBN2E 0.1200000 168 01Jan1983, 16:18 9.94 BEE1 1.0000000 835 01Jan1983, 17:36 9.27 BEE2 1.2 200000 1297 01Jan1983, 16:50 9.22 BEE3 0.8400000 544 01Jan1983, 18:28 8.22 BEEA1 0.6600000 731 01Jan1983, 16:45 9.27 BEEA2 1.1200000 1681 01Jan1983, 16: 11 10.08 BEEA3 0.4600000 363 01Jan1983, 17:42 8.57 BEEBN1 1.0208000 996 01Jan1983, 17:02 8.86 BEE BS 1.0 500000 1083 01Jan1983, 16:47 8.54 BEEBS1 0.5800000 652 01Jan1983, 16:39 8.62 BEEBS2 0.4700000 451 01Jan1983, 17:02 8.45 BEEBS3 0.5200000 468 01Jan1983, 17:13 8.49 FM281 8 2.7799562 2726 01Jan1983, 16:55 8.73 Junction-1 1.5700000 1527 01Jan1983, 16:54 8.53 Junction-2 0.2900000 368 01Jan1983, 16:33 9.83 Junction-3 3.0699562 2839 01Jan1983, 17:16 8.84 Page 1 Hydrologic Drainage Area Peak Discharge Element (Ml2) (CFS) Junction-4 3.1899562 2950 Junction-5 3.4099562 311 6 Junction-6 4.4099562 3793 r ~ ,., Junction-? 5.6299562 41 84 Junction-8 7.8699562 5724 Junction-9 8.7099562 5999 RCH 1 7.8699562 5473 RCH 2 4.4099562 3443 RCH 3 4.4099562 3771 RCH 4 1.0000000 778 RCH 6 3.1899562 2944 RCH 7 2.7799562 25 52 Site '\ 0.0091562 21 ~ .... "". . TRIBA 2.2400000 2528 Page 2 Time of Peak Volume (IN ) 01Jan1 983, 17:13 8.88 01Jan1 983, 17:16 8.96 01Jan1983, 17:26 9.03 1 : II' ' I 01Jan1 983, 18:24 9.06 01Jan1983, 17:39 9.19 ' 01Jan1 983, 18:54 9.08 01Jan1 983, 18:58 9.18 01Jan1 983, 18:43 9.02 01Jan1 983, 17:37 9.03 01Jan1983, 18:11 9.27 01Jan1 983, 17:2 1 8.87 01Jan1 983, 17:22 8.73 01Jan1983, 15:39 10.05 ' 01Jan1 983, 16:31 9.53 w~ wt~{ 1~+e'' V1UMWs cl~ent ~VV\ ~.Q.. A\ f-l6fl h lA v'V\ YJet's I{\ ..\1Vt-L f¥d'? Project: Simulation Run: 100-Year Proposed Start of Run: 01Jan1983, 00:00 End of Run : 04Jan1983, 02:45 Compute Time: 20Jul2009, 10:32:42 Volume Uni ts: IN Basin Model: Proposed Meteorologic Model: 100-Year Control Specifi cation s: Control Hyd rol ogic Drai nage Area Peak Discharge Time of Peak Volume El ement (Ml2) (CFS) (IN) 180 0.6600000 730 01Jan1 983, 16:49 9.27 190 1.7800000 2275 01Jan1 983, 16:28 9.78 290 0.1200000 157 01Jan1 983, 16:36 9.90 310 1.0500000 1083 01Jan1 983, 16:47 8.54 BATEXS 1.7800000 2280 01Jan1 983, 16: 19 9.78 BEBN2A 0.1800000 224 01Jan1 983, 16:31 9.77 BEBN2B 0.1200000 165 01Jan1 983, 16:20 9.90 BEBN2C 0.2200000 348 01Jan1 983, 16:07 10.20 BEBN2D 0.1700000 212 01Jan1983, 16:31 9.78 BEBN2E 0.1200000 168 01Jan1 983, 16:18 9.94 BEE1 1.0000000 835 01Jan1 983, 17:36 9.27 BEE 2 1.2200000 1297 01Jan1983, 16:50 9.22 BEE 3 0.8400000 544 01Jan1 983, 18:28 8.22 BEEA1 0.6600000 731 01Jan1983, 16:45 9.27 BEEA2 1.1 200000 1681 01Jan1 983, 16:11 10.08 BEEA3 0.4600000 363 01Jan 1983, 17:42 8.57 BEEBN 1 1.0208000 996 01Jan 1983, 17:02 8.86 BEE BS 1.0500000 1083 01Jan1 983, 16:47 8.54 BEEBS1 0.5800000 652 01Jan1983, 16:39 8.62 BEEBS2 0.4700000 451 01Jan1 983, 17:02 8.45 BEEBS3 0.5200000 468 01Jan1983, 17:13 8.49 FM2818 2.7799562 2725 01Jan1983, 16:55 8.74 Junction-1 1.5700000 1527 01Jan1 983, 16:54 8.53 Junction-2 0.2900000 368 01Jan1 983, 16:33 9.83 Junction-3 3.0699562 2837 01Jan1 983, 17:1 6 8.84 Page 1 Hydrologic Drainage Area Peak Discharge Time of Peak Volume Element (Ml2) (CFS ) (IN ) Junction-4 3.1899562 2948 01Jan1 983, 17:1 3 8.88 Juncti on-5 3.4099562 311 4 01Jan1 983, 17:16 8.97 Juncti on-6 4.4099562 ! 3791 ·~ 01Ja,n1983, 17:26 9.04 '. . " '· .. Juncti on-? 5.6299562 41 83 01Jan1 983, 18:24 9 06 Junction-8 7.8699562 5723 , ... ,.';., 01Jan1 983, 17:39 9.20 ~· Juncti on-9 8.7099562 5999 01Jan1 983, 18:54 9.09 RCH 1 7.8699562 5473 01Jan1 983, 18:58 9.18 RCH 2 4.4099562 3442 01Jan1 983, 18:43 9.02 RCH 3 4.4099562 3769 01Jan1 983, 17:37 9.03 RCH 4 1.0000000 778 01Jan1 983, 18:11 9.27 RCH 6 3.1899562 2943 01Jan1 983, 17:2 1 8.88 RCH 7 2.7799562 2551 01Jan1 983, 17:22 8.74 Site 0.009 1562 28 . 1.' 01Jan1983, 15:30 12.68 TRIBA 2.2400000 2528 01Jan1 983, 16:31 9.53 Page 2 3,000 2,500 2,000 .--.. ~ 1,500 0 ~ 3 0 LL 1,000 500 Junction "Junction-6'' Resu lts for Ru n "10-Year Existing" o ~~~~~~-=========::=======;:::===~ 00:00 I 12:00 01Jan 1983 00:00 I 12:00 02Jan 1983 --Run:10-YEAR EXISTING Element:JUNCTION-6 ResultOutflow 00:00 I 12:00 03Jan1983 00:00 I 4,000 3,500 3,000 2,500 ,......., ~ 2,000 0 ......., 3 0 u: 1,500 1,000 500 Junction "Junction-8" Results for Run "1 0-Year Existing" o -k:::::=::::::~~~~~~---===========:::;::=:======;d 00:00 I 12:00 01Jan1983 00:00 12:00 00:00 I 02Jan1983 I --Run:10-YEAR EXISTING ElementJUNCTION-8 ResultOutflow 12:00 00 :00 03Jan1983 I -U) LL 0 ~ 3 0 LL Junction "Junction-6'' Results for Run "10-Year Proposed" 3,000 2,500 2,000 1,500 1,000 500 o ~::::::::::~~~~----=========:===:::::=::=:;::::======1 00:00 I 12:00 01Jan1983 00:00 I 12:00 02Jan1983 00:00 I 12:00 00:00 03Jan1983 I --Run:10-YEAR PROPOSED Element:JUNCTION-6 Result:Outflow 4,000 3,500 3,000 2,500 ,.-... ~ 2,000 0 -3 0 LL 1,500 1,000 500 Junction "Junction-8" Results for Run "10-Year Proposed" o ~::::::=--.--~--r~~-.-~=========::;:::::=======:;d 00:00 I 12:00 01Jan1983 00:00 I 12:00 02Jan 1983 --Run 10-YEAR PROPOSED Element:JUNCTION-8 Result:Outflow 00:00 I 12:00 03Jan1983 00:00 I (f) l.J... S2 3 0 u: Junction "Jun ction-6'' Results for Run "50-Year Existing" 4,000 3,500 3,000 2,500 2,000 1,500 1,000 500 o ~:::::=:~~~--.-__:==:====:=;:::=======:::;======r=l 00:00 I 12:00 01Jan1983 00 :00 I 12:00 02Jan1983 00:00 I 12:00 03Jan1983 00:00 I --Run:SO-YEAR EXISTING ElementJUNCTION-6 Result Outflow 6,000 5,000 4,000 ,.-.,. ~ 3,000 u ----3 0 u::: 2,000 1,000 I Junction "Junction -8'' Results for Run "50-Yea r Existing" 0 k~-r-~-.-~--=:====:=====~~==d 00:00 I 12:00 01Jan1 983 00:00 I 12:00 02Jan1983 --Run:SO-YEAR EXISTING ElemenUUNCTION-8 Result:Outflow 00 :00 I 12:00 03Jan 1983 00 :00 I (f) LL 0 ._, ~ _Q LL Junction "Juncti on-6'' Results for Run "SO-Year Proposed " 4,000 3,500 3,000 2,500 2,000 1,500 1,000 500 o ~~:__,_~~-.---=======:::::::===:===~==~ 00:00 I 12:00 01Jan1983 00:00 I 12:00 02Jan1983 00:00 I 12:00 03Jan1983 00:00 I --Run:SO-YEAR PROPOSED Element:JUNCTION-6 Result:Outflow 6,000 5,000 4,000 f2 3,000 u ~ 3 0 i:L 2,000 1,000 Junction "Junction-8" Results for Run "50-Year Proposed" o ~~-.-~~~~~.-.====::======;::=::=====:;=1 00:00 I 12:00 01Jan1983 00:00 I 12 :00 02Jan 1983 --Run:50-YEAR PROPOSED Element:JUNCTION-8 Result:Outflow 00:00 I 12:00 03Jan1983 00:00 I (f) LL 0 -5: 0 LL Junction "Junction-6" Results for Run "100-Year Existing" 4,000 3,500 3,000 2,500 2,000 1,500 1,000 500 o ~~~~~-.---========:=======;:::====;~ 00:00 I 12:00 01Jan1983 00:00 I 12:00 02Jan1983 00:00 I 12:00 03Jan1983 00:00 I --Run :100-YEAR EXISTING ElementJUNCTION-6 Result:Outflow 6,000 5,000 4,000 ,.-. ~ 3,000 0 '-" ~ 0 LL 2,000 1,000 Junction "Junction-8" Results for Run "100-Year Existing" o k~-r-~--..~---======;======;::====d 00:00 12:00 00:00 12:00 00:00 I 01Jan1983 I 02Jan1983 I --Run:100-YEAR EXISTING Element:JUNCTION-8 Result:Outflow 12:00 03Jan1983 00:00 I 4,000 3,500 3,000 2,500 ,......._ f:2 2,000 s 5 0 u.. 1,500 1,000 500 Junction "Junction-6'' Results for Run "100-Year Proposed" o -k:~~~~~-==========:::==:====;::::::======1 00:00 I 12:00 01Jan ·t983 00 :00 12:00 00:00 I 02Jan1983 I --Run 100-YEAR PROPOSED Element:JUNCTION-6 Result:Outflow 12:00 03Jan1983 00:00 I 6,000 5,000 4,000 ,...... ~ 3,000 ~ 3 0 CL 2,000 1,000 Junction "Junction-8" Results for Run "100-Year Proposed" o ~~~~~~~~~=========~========;=:::l 00:00 12:00 00:00 12:00 00:00 12:00 00:00 I 01Jan1983 I 02Jan1983 I 03Jan1983 I --Run:100-YEAR PROPOSED Element:JUNCTION-8 Result:Outflow Alan Gibbs -Southland From: Alan Gibbs To: Joe Orr, Inc. Date: 3/26/2012 9:23 AM Subject: Southland CC: Cotter, Carol; Garza, Venessa Henry, Kimley-Horn Associates, Inc. prepared "Southwest Crossing Floodplain Study for Bee Creek Tributary B" for Oldham- Goodwin for the rv6 AC undeveloped tract between Southland and SW Pkwy. This study was not submitted to FEMA, but is currently the best data. The initial flood elevation on the northern end of the tract was 296.33 ft. The flood elevation at Southland could be a extrapolated to be rv296.5. Alan Gibbs, P.E., CFM City Engineer Planning and Development Services City of College Station P.O. Box 9960 College Station, TX 77842 Office: (979) 764-3570 Fax: (979) 764-3496 Email: agibbs@cstx.gov City of College Station Home of Texas A&M University@ Kimley-Horn and Associates, Inc. 001 ·014-~ n·Ct/f , .. 1£5 Southwest Crossing -College Station, T8+ Memorandum To: Erica Bridges From: Chris Harris Subject: Southwest Crossing, Lot 2-R William Brooke Hunter Estates Response to City Comments Date: July 20, 2009 This memorandum is to address the City of College Station staffs comments on the above mentioned project as received by Kimley-Horn and Associates , Inc. on June 17, 2009. The following information has been included in this submittal for your review. • Response to Comment Letter • One set of revised construction documents • Revised Fire Flow Report • Revised Drainage Study (appendix D) • Updated opinion of probable cost for public infrastructure • Easement Dedication Application Please find the written responses to staffs comments on the following pages. The original city comment is listed followed by our response in bold print. 1. Plan and Profile drawings are required for the proposed public water facilities. Profile has been included. See sheet C-09 and C-10. 2. Please provide City Standard Details for water facilities and erosion control measures. Details have been included. See sheets SWPP, W-1, and W-2. 3. Please submit Easement Dedication Appl ication and associated documents. Easement Dedication Application has been included with this submittal. 4. Please submit a copy of the NOi. Comment addressed. 5. Fire Flow Report -Shouldn't the letter state that the worst case is Building B or C? The letter has been revised to state Building B or C. The associated fire flows are still correct. 6. Sh. C-04 -The FDCs for Buildings A & B need to be within 150-ft of a fire hydrant. Comment addressed. Page 1of 5 KHA Job No. 066076000 K:\CST_Civil\67543000\docs\Response to Review Engineering Comments 20090714.DOC Kimley-Horn and Associates , Inc. Southwest Crossing-College Station, Texas 7. Sh. C-04 -Please label utility lines as "Public" or "Private." Comment addressed. 8. Sh. C-04 Label the existing PUE along the northwestern property line of Lot 1 R with volume and page number. Comment addressed. 9. Sh. C-04 -Verify that all portions of the waterline are at least 5.5-ft away from the edge of the PUE. All proposed water on Lot 2-R has been adjusted to 5.5' min. off the PUE. 10. Sh. C-04 -The proposed waterline on Lot 1 R must be in a minimum 15-ft PUE. The existing water line on Lot 1-R is in a 10' PUE. We are extending the existing line within the existing 10' PUE. This condition was determined to be acceptable per Carol Cotter via email on 711012009. 11 . Sh. C-04 -Please label the isolation valves on the fire suppression lines. Comment addressed. 12. Sh. C-06 -Submit sheet with more legible contours. Comment addressed. 13. Sh. C-07 -Please diminish the areas of proposed fill to include only what is necessary for your project in accordance with the comprehensive site plan . The proposed fill has been designed to attempt to achieve a "zero-rise" condition in order to avoid negative impacts on the adjacent properties. Adjustment of the fill on the north & south ends will result in an increase in water surface elevations. 14. Sh. C-07 -Verify the maximum permitted 4:1 slope is not be exceeded within the fill areas. Comment addressed. Slopes have been modified to 4:1 max. 15. Sh. C-08 -Cleanouts are required at least every 100-ft on the private sanitary sewer line. Comment addressed. 16. Sh . C-08 -The waterline requires a minimum 16-in. steel encasement for the portion crossing Southwest Pkwy. Page 2 of 5 KHA Job No. 066076000 K:ICST _ Civil\67543000\docs\Response to Review Engineering Comments 20090714.DOC Kimley-Horn and Associates, Inc. Southwest Crossing-College Station, Texas Comment addressed. 17. Sh. C-08-A "Dry Mechanical Bore" is preferable for the waterline boring under Southwest Pkwy. Comment addressed. See Water Notes sheet C-08. 18. Sh. C-08 -TS& V may only be used if the tap diameter is less than or equal to half the main line diameter. Please revise. Comment addressed. Intersection has been replaced with a tee and gate valve. 19. Sh. C-08 -Please replace all go· bends with 2-45° bends. Comment addressed. 20. Sh. C-08 -The waterlines should be located at least 15-20-ft away from the buildings. Comment addressed. 21 . Sh. C-08 -Please label proposed waterline sizes. Comment addressed. 22. Sh. C-08 - A 6-in waterline is permitted to have a maximum length of 1500-ft provided it is connected on both ends to an 8-in or larger and has a maximum of 2 fire hydrants. Please verify that the proposed meets these criteria. Proposed waterline has been adjusted to be 8-in diameter. 23. Sh. C-08 -Please provide 2 valves at each tee. Comment addressed. 24. Sh. C-08 -For the sanitary sewer line, please specify SDR26-ASTM. Comment addressed. See Sanitary Sewer Notes sheet C-08. 25. Drainage Report -In accordance with Appendix B, detention is required upstream of Southwest Pkwy. Therefore, this property is not exempt from detention requirements under the Section II criteria . In order to be exempt, additional study of the peak flow timing at the downstream confluences with Trib. B/Bee Creek and Trib. A/Bee Creek will be required in order to show that detention is not necessary. The additional peak flow analysis is included as a separate memo in this submittal. 26. Drainage Report -Our records indicate that the drainage basin upstream of Southwest Pkwy. Is 207 Ac. Please revise. Page 3 of 5 KHA Job No. 066076000 K:\CST _ Civil\67543000\docs\Rcsponse to Review Engineering Comments 20090714.DOC Kimley-Horn and Associates, Inc. Southwest Crossing-College Station, Texas Comment has been disregarded per direction from Carol Cotter via email on 711012009. 27. Drainage Report-Please verify that the "Time of Peak" data given in the tables is supposed to be in "Hours" rather than "minutes." Data presented is in hours and minutes (hr: min), for example, the peak time for basin A 1 in the 10year existing conditions is 21 hours and 07 minutes (21 :07). 28. Drainage Report -What type of velocity dissipation/erosion protection is being proposed at the curb cuts? Rock rip rap pads will be added at curb cuts. See sheet C-11. 29. Drainage Report -Who will be responsible for maintaining the Compensatory Storage Areas and make sure they don't get silted? It is the owner's responsibility to maintain the property within the drainage way. The compensatory storage areas do not become inundated in low flow events. These areas have been generally designed at a 2% slope and should drain into the creek channel. This area will also be seeded and maintained as grassed area. 30. Drainage Report -Please verify that the existing conditions CN of 80 is accurate. The CN of 80 is based on our field observation of the existing conditions and TR-55. The site contains type 'D' soils with brush weed-grass mixture in poor to fair condition. 31 . Drainage Report-Please provide hydrographs. Hydrographs have been provided. 32. Drainage Report -Please clarify the discrepancy between the Peak Flow of 932cfs given in the Flood Study and 1089.Scfs given in the Technical Design Summary. The flow of 932 cfs is the FEMA regulatory flow for this segment of the tributary. The flow of 1089.5 cfs is the flow from the KHA watershed delineation and detention timing study. Page 4 of 5 KHA Job No. 066076000 K:\CST _Civil\67543000\docs\Response to Review Engineering Comments 20090714.00C , . Kimley-Horn and Associates, Inc. Southwest Crossing-College Station, Texas 33. Drainage Report -Please verify that the site only has 25% impervious cover as stated in the report. The site has been reevaluated to have 37% impervious cover. See site area break out below. Southwest Crossing Site Calculations AREA SQUARE FOOTAGE Buildings: 23,569 Driveways: 69,363 Sidewalks: 8,847 Impervious Area: 101,779 37% Pervious Area: 173,796 63% Total Site: 275,575 100% Page 5 of 5 KHA Job No. 066076000 K:ICST _ Civil\67543000\docs\Response to Review Engineering Comments 200907 I 4.DOC Kimley-Horn and Associates, Inc. Technical Memorandum To: C ity of Coll ege Station From: J. Chri s Harris, P.E. Date: July 17, 2009 Subject: Southwest Crossing Purpose Water System Analys is KHA Project No. 067543000 ~, .... ,,, ~E. OF= r '' ~"<,P.., .......... ~-+: \ .... ·· *"·.:rc.S''• I}_..· ···.•'1 p_. . I ~:......... ~·' J cHR;s············: ... , •• ~......... HARRIS ~ \ 94··············.····, ~·._ 859 ... ~~ '~·~~C'E°NS'tQ.···~«l.r ~,~/-b / ,,-,.zo ""°" The proposed development consists of three retail buildings on approximately 5 .5 developed acres. This technical memorandum presents results of the water system analysis for the proposed development. This memorandum is di vided into the fo llowing sections: • References and Design Criteria • Results • Conclusion References and Design Criteria References Water di st ribution mains throughout the development were sized by creating a hydraulic model of the system, usin g WaterCAD version 7.0 by Bentley Systems. The fo ll owing data and references were used for creation of the model: • Fire fl ow tests perfo m1ed by College Station Util iti es on April 14, 2009 near the proposed development site, attached as Appendix A. Design Criteria Water distribution mains were sized based on design criteria listed in the 2008 Bryan I College Station Unified Design Guidelines for Domestic Water. Design criteria used for this analys is includes: • Suite 105 111 University Drive East College Station, Texas 77840 • Peak Flow Conditions Southwest Crossing Water System Analysis July 17 , 2009 Page 2 o Provide minimum pressure of 35 pounds per square inch (psi) • Fire Flow Conditions o Provide a fire flow of 1,000 ga ll ons per minute (gpm) o Provide the requi red fire fl ow at the most hydraulicall y remote pairings of 2 adjacent fire hydrants in the system improvement in addition to the peak hourly fl ow. o A residual pressure of 20 psi is required o Velocity shall not exceed 12 feet per second (fps) The Unified Design Guidelines allow for multiple methods fo r calculation of flow for a development. For this analysis, Method 1 -Fixture Count Detennjnation was used. The fo llowing table represents the peak demands for each building on site. Building Gross Building Peak Demand Area Building A 5,909 sf 25 !!0111 Building B 8,830 sf 30 gpm Building C 8,830 sf 30 gpm The total building square foota ge is 23,569 square feet (SF). T he proposed building type is Type IIB based on International Building Code. For the worst- case building (Building B or C) International Fire Code Table BIOS. I li sts the required fire flow to be 2,000 gpm. Therefore, we have utilized the required minimum fire flow for conunercial from the Des ign Guidelines of 2,500 gpm. This flow has been sp lit between two fire hydrant s on sit e as allowed in the Design Guidelines. Res ults Peak Demand Condition Peak demand conditions are consid ered to be municipal demand as detennined from fixture counts. During peak conditions, system pressures throughout the development are greater than the requi red 35 psi. Resulting pres ures ra nge from 83 psi to 87 psi. WaterCAD results of the peak demand scenario are included as Appendix B of this memorandum. Fire Flow Conditions Southwest Crossing Water System Analysis Jul y 17, 2009 Page 3 The fire flow demand of 2,500 gpm was added to peak fl ow and distributed evenl y at the most hydraulically remote and hi ghest elevation hydrant locations, represented by Junctions FH-1 and Building-AB . Results of the fire flow scena rio show that residual pressures range fro m 73 psi to 80 psi, exceeding the minimum 20 psi requirement. Pipe velociti es are all less than the maximum l 2 fp s. The WaterCAD results for the fire fl ow scenari o are included in Appendix B. Conclusion In conclusion, the water distribution mains proposed fo r the development exceed the minimum requirements as described in this memorandum. Appendix A Fire Flow Test R es ults <Uf College Station Utilities Reliable .. Affordable, Community Owned Date Tuesday April 14, 2009 Time 9:15 Test completed by Justin Tamplin Witness Aaron Matthews Lo cation 1311 Wellborn Nozzle size 2.5 Flow hydrant K-123 Pitot reading 70 G.P.M. 1400 Static hydrant K-080 Static PSI 96 Residual PSI 92 Comments Appendix B M odeling Results .,, ,. / ,,..,., Title: k:lcst_civil\67543000\watercadlproject2.wcd Scenario: Peak+Fire Flow FH·l . 07/14/09 02:38:4~ntley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA ,. '·' •' ~~-1 e.1 Project Engineer: WaterCAD v7.0 (07.00.049.00] +1 -203-755-1666 Page 1 of 1 Label Length b iamete1 Material Hazen-Discharge (ft) (in) William~ (g pm) c P-2 35.00 6.0 PVC 150.0 1,053.12 P-7 254.00 8.0 PVC 150.0 1,531 .88 P-8 30.00 12.0 PVC 150.0 1,531 .88 P-9 23.00 12.0 PVC 150.0 1,53 1.88 P-10 52.00 6.0 PVC 150.0 1,053.12 P-11 190.00 6.0 PVC 150.0 1,053.12 P-1 2 37.00 8.0 PVC 150.0 281.88 P-1 3 33.00 8.0 PVC 150.0 251 .88 P-14 418.00 8.0 PVC 150.0 251 .88 Tille: k:\cst_civil\67543000\watercad\project2.wcd Scenario: Peak+Fire Flow Steady State Analysis Pipe Report Head loss Velocity Gradient (ft/s) (ft/1000ft) 62.63 11 .95 30.87 9.78 4.28 4.35 4.28 4.35 62.63 11 .95 62.63 11 .95 1.34 1.80 1 09 1.61 1 09 1.61 07/14/09 02 :39 :0~nlley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA Project Engineer: WaterCAD v7.0 [07.00.049.00] +1 -203-755-1666 Page 1of 1 Label Elevati on Type Base Flow (ft) (gpm) J-1 300.00 Demand 0.00 Bldg A&I 299.00 Demand 1,305.00 BLDG C 298.00 Demand 30.00 J-5 296.00 Demand 0.00 FH-1 296.00 Demand 1,250.00 J-7 294.00 Demand 0.00 Title: k:\cst_civil\67543000\watercad\project2.wcd Scenario: Peak+Fire Flow Steady State Analysis Junction Report Demand Calculated Pressure Calculated Hydraulic Grad ~ (psi) (gpm) (ft) 0.00 474.53 75.51 1,305.00 4 72.34 75.00 30.00 472.83 75.64 0.00 472.80 76.4 9 1,250.00 472.88 76.53 000 480.72 80.79 07/14/09 02 :39:1~ntley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA Project Engineer: WaterCAD v7.0 [07.00.049.00] +1-203-755-1666 Page 1 of 1 Label Elevation Type Base Flow (ft) (gpm) J-1 300.00 Demand 0 00 Bldg A&I 299.00 Demand 55.00 BLDG C 298.00 Demand 30.00 J-5 296.00 Demand 0.00 FH-1 296.00 Demand 0.00 J-7 294 .00 Demand 0.00 Title: k:lcst_civil1675430001watercadlproject2.wcd Scenario: Peak Demand Steady State Analysis Junction Report Demand Calculated Pressure Ca lculated Hydraulic Grad; (psi) (gpm) (ft ) 0 .00 493.98 83.92 55.00 493.97 84.36 30.00 493.98 84.79 0.00 493.98 85.66 0.00 493.98 85.66 0 00 494.00 86.53 07/1 4/09 02:39 :3~ntley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA Project Engineer: WaterCAD v7 .0 (07.00.049.00J +1-203-755-1666 Page 1of 1 I ' Label Length Oiamete1 Material Hazen-DischargE (ft) (in ) William~ (gpm) c P-2 35.00 6.0 PVC 150.0 31.12 P-7 254.00 8.0 PVC 150.0 -53.88 P-8 30.00 12.0 PVC 150.0 -53.88 P-9 23.00 12.0 PVC 150.0 -53.88 P-10 52.00 6.0 PVC 150.0 31.12 P-11 190.00 6.0 PVC 150.0 31.12 P-12 37.00 8.0 PVC 150.0 53.88 P-13 33.00 8.0 PVC 150.0 23.88 P-14 418.00 8.0 PVC 150.0 23.88 Title: k:\cst_civil\67543000\watercad\project2.wcd Scenario: Peak Demand Steady State Analysis Pipe Report Head loss Velocity Gradient (ft/s) (ft/1 OOOft) 0.09 0.35 0.06 0.34 0.01 0.15 0.01 0.15 0.09 0.35 0.09 0.35 0.06 0.34 0.01 0.15 0.01 0.15 07/14/09 02:39 5©=1Mntley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA Project Engineer: WaterCAD v7.0 [07.00.049.00] +1-203-755-1666 Page 1of1