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Report P1 1202(—00044 14 to50 SIA1 Ave TECHNICAL MEMORANDUM L,T.', Cardno Prepared for: Tigard-Tualatin School District 6960 SW Sandburg Street 6720 S Macadam Ave. Tigard, Oregon 97223 Suite 150 Portland,OR 97219 From: Matt Lewis, P.E. Matt.Lewis@cardno.com Phone (503)419.2500 Fax (503)419-2600 Date: January 28, 2021 www.cardno.com Project: Twality Middle School Athletic Field OFFICE COPY Cardno#: 22015500 1 Re: Stormwater Memo Introduction The Twality Middle School Athletic Field project consists of a new artificial turf field that will replace the existing grass field. The new field is within the same footprint of the existing grass field and is 99,167 square feet or 2.28 acres.The proposed field will be replaced with artificial turf that will have a section that closely mimics porous asphalt, as to allow infiltration. Additional improvements will also include providing an overflow pipe and trench drain, as well as re-surfacing the existing track. Water Quantity Detention A review of NRCS mapping shows the underlying soil type is Cornelius and Kinton silt loarns (see Technical Appendix, Twality MS Field Hydrologic Soil Group). The proposed athletic field is designed to infiltrate following the porous pavement methodology as described in 4.09.15, and will not add any additional storage volume to any of the downstream detention facilities. As part of the athletic field section, we have provided a 4"section of drain rock that will provide storage for the 10 year, 24 hour storm event (see Appendix, Exhibit 1). We used the simplified approach for that soil series which indicates the soil is in hydrologic soil group C and drains moderately well. This allows us to apply 0.5 in/ hr infiltration rate (CWS Manual, Table 4-5). Using the SBUH method (see Appendix, Exhibit 2) the amount of volume exceeding the threshold of 1.15 CFS is 1023 CF over the area of the field. This threshold was calculated by using the 0.5 in/hr infiltration rate multiplied over the area of the field.The remaining hydrograph volume to be stored is the area under the curve above that threshold, which calculates to 1023 CF. Distributing that volume over the entire field and accounting for 40%porosity, results in a required storage depth of 0.17 inches. In addition to this 4" drain rock storage section, we have in place additional drain rock, and placed an 8"perforated pipe down the east side of the field for any potential overflow of the rock sections. To accommodate the existing track runoff,we placed a trench drain around the perimeter of the turf field to capture the runoff and placed a solid 6"pipe below the field surface that was sized based on the 10 year peak flow using the SBUH method (see Appendix, Exhibit 3). This pipe then conveys the track runoff and ties into the existing storm system. Downstream Analysis The report created by KPFF for the Twality Middle School and Templeton Elementary School projects dated 12/11/2018, show a downstream deficiency, thus, two Extended Dry Basins to accommodate those improvements were constructed. The proposed athletic field is designed to infiltrate following the porous pavement methodology as described in 4.09.15 and will not increase runoff to the existing Extended Dry Basins, and will not increase the 25-year discharge rate from the site to the public storm sewer system. -44 Page 2 January 28,2021 Cardna Hydromodification The proposed project does not construct or modify impervious area, thus the amount or rate of surface water runoff leaving the site does not significantly increase. Water Quality Treatment The proposed project does not construct or modify impervious area, thus the amount or rate of surface water runoff or pollution leaving the site does not significantly increase. Previous to this project,the existing track runoff flowed directly onto the existing grass field. To keep the track runoff from draining onto the new athletic field and to ensure this runoff is treated, we placed a trench drain around the perimeter of the turf field to capture the runoff, then convey to the existing onsite storm system to then be treated by the existing Extended Dry Basin downstream. Conclusion The proposed improvements are meeting City of Tigard and CWS requirements through the use of a modified porous pavement approach as it pertains to the proposed artificial turf field and other limited improvements. itteleilkeA.46. e tal 7862 att L Signature of Engineer ature Q2g021.01.29 re Q6:42:I: ::'00' 2021-01-29 OREuN � 741 09. � �' Date �TtHEW C d� RENEWS 12,3112022 Technical Appendix • Twality MS Field Hydrologic Soil Group • Exhibit 1 —C3.00—Grading &Storm Plan • Exhibit 2—SBUH—Field Storage • Exhibit 3—SBUH—Track Runoff Pipe Sizing Hydrologic Soil Group—Washington County,Oregon $ (Twality MS Field) 517640 517660 517690 517700 517720 517740 517703 45°24'53"N 45.24'53'N 9 { I ' Mk p a. I Ii - 6 , i '," .,, u tt item 1� 1 1'�+i iM'`;lc .,a'C•I ii wilt, - * 45°24'47 N 48.2447'N 517640 517633 5178® 5177C0 517720 517740 517760 3 3 Map Scale:1:901 ifprinted on A portrat(8.5"x 111 sheet ."."" Metes N c 10 m 40 co Feet .'_1 A0 40 80 160 240 Map projection:Web Mercator Comer oxrdinates:WGS84 Edge tics:UTM Zone lON WGS84 USDA, Natural Resources Web Soil Survey 11/9/2020 aid Conservation Service National Cooperative Soil Survey Page 1 of 4 Hydrologic Soil Group—Washington County,Oregon Twality MS Field Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 11B Cornelius and Kinton silt C 2.3 100.0% barns,2 to 7 percent slopes Totals for Area of Interest 2.3 1 100.0% Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D)and three dual classes(A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential)when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential)when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group(ND, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method:Dominant Condition tSrM Natural Resources Web Soil Survey 11/9/2020 i1110 Conservation Service National Cooperative Soil Survey Page 3 of 4 Hydrologic Soil Group—Washington County,Oregon Twality MS Field Component Percent Cutoff: None Specified Tie-break Rule: Higher i sDk Natural Resources Web Soil Survey 11/9/2020 "111.1 Conservation Service National Cooperative Soil Survey Page 4 of 4 Exhibit 2 L' Cardno Project: Twality MS Athletic Field Project Number: 22015500 SANTA BARBARA URBAN HYDROGRAPH Date: 01/28/2021 SCS TYPE 1A 24-HOUR DISTRIBUTION Basin: Athletic Field Event: 10-Year Post Dev. Given: Area= 228 acres Pt = 3 45 inches dt = 10 min. Tc = 5 min. w = 0.5000 routing constant Pervious Area Impervious Area HYDROGRAPH RESULTS Area= 0 acres Area = 2.28 acres Peak Runol 2.052 cfs CN = 85 CN = 98 Total Vol.: 26565 cf S = 1.76 S = 0.20 0.2S= 0.35 0.2S = 0.04 Peak Runoff Hydrograph 2.500 . I i J J t 2.000 — ..._ .. i , .- -- r., .. 01.500 ( , 0 01.15 , i 1.000 G f ' 1 0.500 i l z.fx1 r 0000 0 200 400 600 800 1000 1200 1400 1600 Time in Minutes File 1550-SBUH-24.xls 1/27/2021 Cardno Page I i Pervious Area Impervious Area (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) Time Time Rainfall Incre- Accumu- Accumu- Incre- Accumu- Incre- Total Instant Design Incre- Distri- mental lated lated mental lated mental Runoff Hydro- Hydro- ment bution Rainfall Rainfall Runoff Runoff Runoff Runoff graph graph (Min) (%of Pt) (in) (in) (in) (in) (in) (in) (in) (cfs) (cfs) 1 10 0.0040 0.0138 0.0138 0.0000 0.0000 0.0000 0.0000 0.0000 0.0 0.000 2 20 0.0040 0.0138 0.0276 0.0000 0.0000 0.0000 0.0000 0.0000 0.0 0.000 3 30 0.0040 0.0138 0.0414 0.0000 0.0000 0.0000 0.0000 0.0000 0.0 0.000 4 40 0.0040 0.0138 0.0552 0.0000 0.0000 0.0009 0.0009 0.0009 0.0 0.007 5 50 0.0040 0.0138 0.0690 0.0000 0.0000 0.0034 0.0025 0.0025 0.0 0.024 6 60 0.0040 0.0138 0.0828 0.0000 0.0000 0.0072 0.0037 0.0037 0.1 0.043 7 70 0.0040 0.0138 0.0966 0.0000 0.0000 0.0120 0.0048 0.0048 0.1 0.059 8 80 0.0040 0.0138 0.1104 0.0000 0.0000 0.0177 0.0057 0.0057 0.1 0.073 9 90 0.0040 0.0138 0.1242 0.0000 0.0000 0.0242 0.0065 0.0065 0.1 0.084 10 100 0.0040 0.0138 0.1380 0.0000 0.0000 0.0313 0.0072 0.0072 0.1 0.094 11 110 0.0050 0.0173 0.1553 0.0000 0.0000 0.0411 0.0098 0.0098 0.1 0.117 12 120 0.0050 0.0173 0.1725 0.0000 0.0000 0.0516 0.0105 0.0105 0.1 0.140 13 130 0.0050 0.0173 0.1898 0.0000 0.0000 0.0628 0.0112 0.0112 0.2 0.150 14 140 0.0050 0.0173 0.2070 0.0000 0.0000 0.0746 0.0118 0.0118 0.2 0.158 15 150 0.0050 0.0173 0.2243 0.0000 0.0000 0.0868 0.0122 0.0122 0.2 0.166 16 160 0.0050 0.0173 0.2415 0.0000 0.0000 0.0995 0.0127 0.0127 0.2 0.172 17 170 0.0060 0.0207 0.2622 0.0000 0.0000 0.1152 0.0157 0.0157 0.2 0.196 18 180 0.0060 0.0207 0.2829 0.0000 0.0000 0.1314 0.0162 0.0162 0.2 0.220 19 190 0.0060 0.0207 0.3036 0.0000 0.0000 0.1479 0.0166 0.0166 0.2 0.226 20 200 0.0060 0.0207 0.3243 0.0000 0.0000 0.1648 0.0169 0.0169 0.2 0.231 21 210 0.0060 0.0207 0.3450 0.0000 0.0000 0.1820 0.0172 0.0172 0.2 0.235 22 220 0.0060 0.0207 0.3657 0.0001 0.0001 0.1995 0.0175 0.0175 0.2 0.239 23 230 0.0070 0.0242 0.3899 0.0008 0.0007 0.2203 0.0207 0.0207 0.3 0.264 24 240 0.0070 0.0242 0.4140 0.0020 0.0013 0.2413 0.0210 0.0210 0.3 0.288 25 250 0.0070 0.0242 0.4382 0.0039 0.0019 0.2625 0.0213 0.0213 0.3 0.291 26 260 0.0070 0.0242 0.4623 0.0064 0.0025 0.2840 0.0215 0.0215 0.3 0.295 27 270 0.0070 0.0242 0.4865 0.0094 0.0030 0.3057 0.0217 0.0217 0.3 0.298 28 280 0.0070 0.0242 0.5106 0.0129 0.0035 0.3275 0.0219 0.0219 0.3 0.300 29 290 0.0082 0.0283 0.5389 0.0177 0.0048 0.3533 0.0258 0.0258 0.4 0.329 30 300 0.0082 0.0283 0.5672 0.0232 0.0055 0.3793 0.0260 0.0260 0.4 0.357 31 310 0.0082 0.0283 0.5955 0.0293 0.0061 0.4055 0.0262 0.0262 0.4 0.360 32 320 0.0082 0.0283 0.6238 0.0360 0.0067 0.4318 0.0263 0.0263 0.4 0.362 33 330 0.0082 0.0283 0.6521 0.0433 0.0073 0.4582 0.0265 0.0265 0.4 0.364 34 340 0.0082 0.0283 0.6803 0.0512 0.0079 0.4848 0.0266 0.0266 0.4 0.366 35 350 0.0095 0.0328 0.7131 0.0611 0.0098 0.5157 0.0309 0.0309 0.4 0.397 36 360 0.0095 0.0328 0.7459 0.0716 0.0105 0.5468 0.0311 0.0311 0.4 0.428 37 370 0.0095 0.0328 0.7787 0.0827 0.0112 0.5780 0.0312 0.0312 0.4 0.429 38 380 0.0095 0.0328 0.8114 0.0946 0.0118 0.6093 0.0313 0.0313 0.4 0.431 39 390 0.0095 0.0328 0.8442 0.1070 0.0124 0.6407 0.0314 0.0314 0.4 0.432 40 400 0.0095 0.0328 0.8770 0.1200 0.0130 0.6721 0.0315 0.0315 0.4 0.434 41 410 0.0134 0.0462 0.9232 0.1393 0.0193 0.7167 0.0445 0.0445 0.6 0.524 42 420 0.0134 0.0462 0.9695 0.1596 0.0203 0.7613 0.0447 0.0447 0.6 0.615 43 430 0.0134 0.0462 1.0157 0.1809 0.0213 0.8061 0.0448 0.0448 0.6 0.617 44 440 0.0180 0.0621 1.0778 0.2110 0.0301 0.8664 0.0603 0.0603 0.8 0.725 45 450 0.0180 0.0621 1.1399 0.2427 0.0317 0.9269 0.0605 0.0605 0.8 0.833 46 460 0.0340 0.1173 1.2572 0.3064 0.0637 1.0416 0.1147 0.1147 1.6 1.208 47 470 0.0540 0.1863 1.4435 0.4165 0.1102 1.2245 0.1829 0.1829 2.5 2.052 48 480 0.0270 0.0932 1.5366 0.4752 0.0587 1.3162 0.0917 0.0917 1.3 1.894 49 490 0.0180 0.0621 1.5987 0.5155 0.0403 1.3775 0.0612 0.0612 0.8 1.055 50 500 0.0134 0.0462 1.6450 0.5461 0.0306 1.4231 0.0456 0.0456 0.6 0.737 51 510 0.0134 0.0462 1.6912 0.5772 0.0311 1.4688 0.0457 0.0457 0.6 0.630 52 520 0.0134 0.0462 1.7374 0.6087 0.0315 1.5144 0.0457 0.0457 0.6 0.630 53 530 0.0088 0.0304 1.7678 0.6296 0.0209 1.5445 0.0300 0.0300 0.4 0.522 54 540 0.0088 0.0304 1.7981 0.6507 0.0211 1.5745 0.0300 0.0300 0.4 0.414 55 550 0.0088 0.0304 1.8285 0.6719 0.0213 1.6045 0.0300 0.0300 0.4 0.414 56 560 0.0088 0.0304 1.8589 0.6934 0.0214 1.6346 0.0300 0.0300 0.4 0.414 57 570 0.0088 0.0304 1.8892 0.7150 0.0216 1.6646 0.0301 0.0301 0.4 0.415 58 580 0.0088 0.0304 1.9196 0.7367 0.0218 1.6947 0.0301 0.0301 0.4 0.415 59 590 0.0088 0.0304 1.9499 0.7587 0.0219 1.7248 0.0301 0.0301 0.4 0.415 60 600 0.0088 0.0304 1.9803 0.7807 0.0221 1.7548 0.0301 0.0301 0.4 0.415 61 610 0.0088 0.0304 2.0107 0.8029 0.0222 1.7849 0.0301 0.0301 0.4 0.415 62 620 0.0088 0.0304 2.0410 0.8253 0.0224 1.8150 0.0301 0.0301 0.4 0.415 63 630 0.0088 0.0304 2.0714 0.8478 0.0225 1.8451 0.0301 0.0301 0.4 0.415 64 640 0.0088 0.0304 2.1017 0.8704 0.0226 1.8752 0.0301 0.0301 0.4 0.415 65 650 0.0072 0.0248 2.1266 0.8891 0.0186 1.8999 0.0246 0.0246 0.3 0.378 66 660 0.0072 0.0248 2.1514 0.9078 0.0187 1.9245 0.0246 0.0246 0.3 0.340 67 670 0.0072 0.0248 2.1763 0.9266 0.0188 1.9492 0.0246 0.0246 0.3 0.340 68 680 0.0072 0.0248 2.2011 0.9454 0.0189 1.9738 0.0247 0.0247 0.3 0.340 69 690 0.0072 0.0248 2.2259 0.9644 0.0190 1.9985 0.0247 0.0247 0.3 0.340 70 700 0.0072 0.0248 2.2508 0.9834 0.0190 2.0231 0.0247 0.0247 0.3 0.340 71 710 0.0072 0.0248 2.2756 1.0025 0.0191 2.0478 0.0247 0.0247 0.3 0.340 72 720 0.0072 0.0248 2.3005 1.0217 0.0192 2.0725 0.0247 0.0247 0.3 0.340 73 730 0.0072 0.0248 2.3253 1.0410 0.0193 2.0971 0.0247 0.0247 0.3 0.340 74 740 0.0072 0.0248 2.3501 1.0603 0.0193 2.1218 0.0247 0.0247 0.3 0.340 File:1550-SBU H-24.xls 1/27/2021 Cardno Page 2 r (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) Time Time Rainfall Incre- Accumu- Accumu- Incre- Accumu- Incre- Total Instant Design Incre- Distil- mental lated lated mental lated mental Runoff Hydro- Hydro- ment bution Rainfall Rainfall Runoff Runoff Runoff Runoff graph graph (Min) (%of Pt) (in) (in) (in) (in) (in) (in) (in) (cfs) (cfs) 75 750 0.0072 0.0248 2.3750 1.0797 0.0194 2.1465 0.0247 0.0247 0.3 0.340 76 760 0.0072 0.0248 2.3998 1.0992 0.0195 2.1712 0.0247 0.0247 0.3 0.340 77 770 0.0057 0.0197 2.4195 1.1147 0.0155 2.1907 0.0195 0.0195 0.3 0.305 78 780 0.0057 0.0197 2.4392 1.1302 0.0155 2.2103 0.0195 0.0195 0.3 0.270 79 790 0.0057 0.0197 2.4588 1.1457 0.0156 2.2298 0.0195 0.0195 0.3 0.270 80 800 0.0057 0.0197 2.4785 1.1613 0.0156 2.2493 0.0195 0.0195 0.3 0.270 81 810 0.0057 0.0197 2.4981 1.1770 0.0156 2.2689 0.0195 0.0195 0.3 0.270 82 820 0.0057 0.0197 2.5178 1.1927 0.0157 2.2884 0.0196 0.0196 0.3 0.270 83 830 0.0057 0.0197 2.5375 1.2084 0.0157 2.3080 0.0196 0.0196 0.3 0.270 84 840 0.0057 0.0197 2.5571 1.2241 0.0158 2.3276 0.0196 0.0196 0.3 0.270 85 850 0.0057 0.0197 2.5768 1.2399 0.0158 2.3471 0.0196 0.0196 0.3 0.270 86 860 0.0057 0.0197 2.5965 1.2558 0.0158 2.3667 0.0196 0.0196 0.3 0.270 87 870 0.0057 0.0197 2.6161 1.2716 0.0159 2.3862 0.0196 0.0196 0.3 0.270 88 880 0.0057 0.0197 2.6358 1.2876 0.0159 2.4058 0.0196 0.0196 0.3 0.270 89 890 0.0050 0.0173 2.6531 1.3015 0.0140 2.4229 0.0172 0.0172 0.2 0.253 90 900 0.0050 0.0173 2.6703 1.3155 0.0140 2.4401 0.0172 0.0172 0.2 0.237 91 910 0.0050 0.0173 2.6876 1.3296 0.0140 2.4573 0.0172 0.0172 0.2 0.237 92 920 0.0050 0.0173 2.7048 1.3437 0.0141 2.4744 0.0172 0.0172 0.2 0.237 93 930 0.0050 0.0173 2.7221 1.3577 0.0141 2.4916 0.0172 0.0172 0.2 0.237 94 940 0.0050 0.0173 2.7393 1.3719 0.0141 2.5088 0.0172 0.0172 0.2 0.237 95 950 0.0050 0.0173 2.7566 1.3860 0.0141 2.5259 0.0172 0.0172 0.2 0.237 96 960 0.0050 0.0173 2.7738 1.4002 0.0142 2.5431 0.0172 0.0172 0.2 0.237 97 970 0.0050 0.0173 2.7911 1.4144 0.0142 2.5602 0.0172 0.0172 0.2 0.237 98 980 0.0050 0.0173 2.8083 1.4286 0.0142 2.5774 0.0172 0.0172 0.2 0.237 99 990 0.0050 0.0173 2.8256 1.4428 0.0142 2.5946 0.0172 0.0172 0.2 0.237 100 1000 0.0050 0.0173 2.8428 1.4571 0.0143 2.6118 0.0172 0.0172 0.2 0.237 101 1010 0.0040 0.0138 2.8566 1.4686 0.0114 2.6255 0.0137 0.0137 0.2 0.213 102 1020 0.0040 0.0138 2.8704 1.4800 0.0114 2.6392 0.0137 0.0137 0.2 0.189 103 1030 0.0040 0.0138 2.8842 1.4915 0.0115 2.6530 0.0137 0.0137 0.2 0.189 104 1040 0.0040 0.0138 2.8980 1.5029 0.0115 2.6667 0.0137 0.0137 0.2 0.190 105 1050 0.0040 0.0138 2.9118 1.5144 0.0115 2.6804 0.0137 0.0137 0.2 0.190 106 1060 0.0040 0.0138 2.9256 1.5259 0.0115 2.6942 0.0137 0.0137 0.2 0.190 107 1070 0.0040 0.0138 2.9394 1.5375 0.0115 2.7079 0.0137 0.0137 0.2 0.190 108 1080 0.0040 0.0138 2.9532 1.5490 0.0115 2.7217 0.0137 0.0137 0.2 0.190 109 1090 0.0040 0.0138 2.9670 1.5606 0.0116 2.7354 0.0137 0.0137 0.2 0.190 110 1100 0.0040 0.0138 2.9808 1.5721 0.0116 2.7491 0.0137 0.0137 0.2 0.190 111 1110 0.0040 0.0138 2.9946 1.5837 0.0116 2.7629 0.0137 0.0137 0.2 0.190 112 1120 0.0040 0.0138 3.0084 1.5953 0.0116 2.7766 0.0137 0.0137 0.2 0.190 113 1130 0.0040 0.0138 3.0222 1.6069 0.0116 2.7904 0.0137 0.0137 0.2 0.190 114 1140 0.0040 0.0138 3.0360 1.6185 0.0116 2.8041 0.0137 0.0137 0.2 0.190 115 1150 0.0040 0.0138 3.0498 1.6302 0.0116 2.8179 0.0137 0.0137 0.2 0.190 116 1160 0.0040 0.0138 3.0636 1.6418 0.0116 2.8316 0.0137 0.0137 0.2 0.190 117 1170 0.0040 0.0138 3.0774 1.6535 0.0117 2.8454 0.0137 0.0137 0.2 0.190 118 1180 0.0040 0.0138 3.0912 1.6651 , 0.0117 2.8591 0.0137 0.0137 0.2 0.190 119 1190 0.0040 0.0138 3.1050 1.6768 0.0117 2.8728 0.0137 0.0137 0.2 0.190 120 1200 0.0040 0.0138 3.1188 1.6885 0.0117 2.8866 0.0137 0.0137 0.2 0.190 121 1210 0.0040 0.0138 3.1326 1.7002 0.0117 2.9003 0.0137 0.0137 0.2 0.190 122 1220 0.0040 0.0138 3.1464 1.7120 0.0117 2.9141 0.0137 0.0137 0.2 0.190 123 1230 0.0040 0.0138 3.1602 1.7237 0.0117 2.9278 0.0137 0.0137 0.2 0.190 124 1240 0.0040 0.0138 3.1740 1.7355 0.0118 2.9416 0.0137 0.0137 0.2 0.190 125 1250 0.0040 0.0138 3.1878 1.7472 0.0118 2.9553 0.0137 0.0137 0.2 0.190 126 1260 0.0040 0.0138 3.2016 1.7590 0.0118 2.9691 0.0137 0.0137 0.2 0.190 127 1270 0.0040 0.0138 3.2154 1.7708 0.0118 2.9828 0.0137 0.0137 0.2 0.190 128 1280 0.0040 0.0138 3.2292 1.7826 0.0118 2.9966 0.0137 0.0137 0.2 0.190 129 1290 0.0040 0.0138 3.2430 1.7944 0.0118 3.0103 0.0138 0.0138 0.2 0.190 130 1300 0.0040 0.0138 3.2568 1.8062 0.0118 3.0241 0.0138 0.0138 0.2 0.190 131 1310 0.0040 0.0138 3.2706 1.8180 0.0118 3.0378 0.0138 0.0138 0.2 0.190 132 1320 0.0040 0.0138 3.2844 1.8299 0.0118 3.0516 0.0138 0.0138 0.2 0.190 133 1330 0.0040 0.0138 3.2982 1.8417 0.0119 3.0653 0.0138 0.0138 0.2 0.190 134 1340 0.0040 0.0138 3.3120 1.8536 0.0119 3.0791 0.0138 0.0138 0.2 0.190 135 1350 0.0040 0.0138 3.3258 1.8655 0.0119 3.0928 0.0138 0.0138 0.2 0.190 136 1360 0.0040 0.0138 3.3396 1.8774 0.0119 3.1066 0.0138 0.0138 0.2 0.190 137 1370 0.0040 0.0138 3.3534 1.8893 0.0119 3.1203 0.0138 0.0138 0.2 0.190 138 1380 0.0040 0.0138 3.3672 1.9012 0.0119 3.1341 0.0138 0.0138 0.2 0.190 139 1390 0.0040 0.0138 3.3810 1.9131 0.0119 3.1479 0.0138 0.0138 0.2 0.190 140 1400 0.0040 0.0138 3.3948 1.9251 0.0119 3.1616 0.0138 0.0138 0.2 0.190 141 1410 0.0040 0.0138 3.4086 1.9370 0.0119 3.1754 0.0138 0.0138 0.2 0.190 142 1420 0.0040 0.0138 3.4224 1.9490 0.0120 3.1891 0.0138 0.0138 0.2 0.190 143 1430 0.0040 0.0138 3.4362 1.9609 0.0120 3.2029 0.0138 0.0138 0.2 0.190 144 1440 0.0040 0.0138 3.4500 1.9729 0.0120 3.2166 0.0138 0.0138 0.2 0.190 Total 1.0000 3.4500 Hydrograph Volume 26565 (Cubic Feet) File:1550-S B U H-24.xls 1/27/2021 Cardno Page 3