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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />Loss es <br />Losses due to infiltration and depression storage were estimated from U.S.D.A. Soil <br />Conservation Service Soil Surveys, Reference Q, and the Urban Storm Drainalle Criteria <br />Manual, Reference E. Because of the insufficient and conflicting data on typical <br />infiltration decay rates, a zero decay rate was assumed and a constant infiltration rate <br />based on an average of the published minimum and maximum infiltration rates was used. <br />Maximum depression storage values were obtained from the Urban Storm Drainage <br />Criteria Manual. Values of infiltration rates and depression storage used in each subbasin <br />are listed in Table Ill-2. <br /> <br />Flood Hydroro-aphs <br />Selected flood hydrographs for the 100-year flood (future basin conditions) as deter- <br />mined using the "SWMM" program are shown in Figures III-5 through III-I0. Peak flood <br />flows for the various design storms considered in the study have been plotted against the <br />channel reference stationing in the Peak Flood Discharge Curves, Figures Ill-I, Ill-2 and <br />1II-3. The 100-year and design flood peaks are listed on each sheet of the drawings with <br />the corresponding channel section, conduit, or detention facility. More detailed <br />information on the hydrologic analysis is available at the office of the Urban Drainage <br />and Flood Control District. <br /> <br />TABLE III-I <br /> <br />RAINF ALL VALUES <br /> <br />(total inChes) <br /> <br />Duration (hours) <br /> <br />3 <br /> <br />1 <br /> <br />2 <br /> <br />6 <br /> <br />24 <br /> <br />Recurrence Interval <br /> <br />2 year <br /> <br />0.93 <br />1.28 <br /> <br />1.14 <br /> <br />1.29 <br /> <br />1.52 <br /> <br />2.10 <br /> <br />5 year <br /> <br />1.54 <br /> <br />1. 72 <br /> <br />2.00 <br /> <br />2.77 <br /> <br />10 year <br /> <br />1.55 <br />1.90 <br /> <br />1.84 <br />2.23 <br />2.54 <br /> <br />2.05 <br /> <br />2.37 <br />2.86 <br /> <br />3.27 <br />3.93 <br /> <br />25 year <br /> <br />2.49 <br />2.82 <br /> <br />50 year <br /> <br />2.17 <br />2.44 <br /> <br />3.23 <br /> <br />4.44 <br />4.94 <br /> <br />100 year <br /> <br />2.84 <br /> <br />3.15 <br /> <br />3.60 <br /> <br />ill - 2 <br /> <br />Subar ea <br />Number <br /> <br />1 <br />2 <br />3 <br />4 <br />5 <br />6 <br />7 <br />8 <br />9 <br />10 <br />11 <br />12 <br />13 <br />14 <br />15 <br />16 <br />17 <br />18 <br />19 <br />20 <br />21 <br />22 <br />23 <br />24 <br />25 <br />26 <br />27 <br />28 <br />29 <br />30 <br />31 <br />32 <br />33 <br />34 <br />35 <br />36 <br />37 <br />38 <br />39 <br />41 <br />42 <br />43 <br />44 <br />45 <br />46 <br />47 <br />48 <br />49 <br /> <br />Channel <br />Segment <br />For <br />Drainage <br /> <br />1 <br />1 <br />36 <br />33 <br />32 <br />34 <br />30 <br />29 <br />28 <br />48 <br />7 <br />3 <br />4 <br />6 <br />38 <br />39 <br />8 <br />9 <br />42 <br />21 <br />43 <br />44 <br />13 <br />12 <br />14 <br />10 <br />27 <br />50 <br />24 <br />25 <br />45 <br />15 <br />17 <br />19 <br />19 <br />26 <br />18 <br />47 <br />49 <br />32 <br />2 <br />35 <br />40 <br />41 <br />20 <br />46 <br />50 <br />37 <br /> <br />TABLE Ill-2: LITTLE DRY CREEK DRAINAGE BASIN DATA <br /> <br />Area Percent Slope <br />(Ac) Imperv. (Ft/Ft) <br /> <br />181.6 <br />143.1 <br />119.0 <br />99.7 <br />227.6 <br />23.0 <br />186.6 <br />114.7 <br />39.1 <br />39.4 <br />92.6 <br />178.9 <br />217.8 <br />115.7 <br />226.3 <br />231. 7 <br />83.7 <br />225.5 <br />166.4 <br />229.6 <br />14355 <br />177.9 <br />315.2 <br />86.3 <br />166.7 <br />146,2 <br />155,9 <br />431. 7 <br />182.5 <br />301.1 <br />704.9 <br />330.3 <br />180.2 <br />108.7 <br />175.6 <br />225.7 <br />67.3 <br />91.1 <br />170.7 <br />41.3 <br />142.4 <br />87.6 <br />143.5 <br />217.9 <br />154.5 <br />108.2 <br />153.8 <br />32.0 <br /> <br />34.3 <br />26.0 <br />28.0 <br />21.0 <br />30.0 <br />21.0 <br />31.0 <br />28.0 <br />29.0 <br />27.0 <br />33.0 <br />25.0 <br />26.0 <br />33.4 <br />10.1 <br />32.0 <br />25.0 <br />32.0 <br />36.0 <br />33.0 <br />31.0 <br />30.0 <br />37.0 <br />34.0 <br />49.0 <br />30.0 <br />34.0 <br />32.0 <br />35.0 <br />30.0 <br />42.0 <br />41.0 <br />32.0 <br />25.0 <br />23.0 <br />46.0 <br />30.0 <br />34.0 <br />30.0 <br />34.0 <br />27.0 <br />24.0 <br />36.4 <br />33.5 <br />33.0 <br />31.0 <br />34.0 <br />22.0 <br /> <br />.0250 <br />.0370 <br />.0383 <br />.0370 <br />.0300 <br />.0682 <br />.0471 <br />.0333 <br />.0348 <br />.0268 <br />.0470 <br />.0449 <br />.0395 <br />.0541 <br />.0350 <br />.0510 <br />.0430 <br />.0400 <br />.0200 <br />.0140 <br />.0213 <br />.0258 <br />.0240 <br />.0175 <br />.0269 <br />.0334 <br />.0258 <br />.0370 <br />.0233 <br />.0406 <br />.0289 <br />.0238 <br />.0180 <br />.0726 <br />.0200 <br />.0156 <br />.0167 <br />.0333 <br />.0468 <br />.0482 <br />.0440 <br />.0390 <br />.0230 <br />.0240 <br />.0340 <br />.0390 <br />.0350 <br />.0340 <br /> <br />Resistance <br />Imperv. <br /> <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />,026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br />.026 <br /> <br />Factor <br />Perv. <br /> <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.250 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.260 <br />.250 <br />.250 <br />.250 <br />.250 <br />.250 <br />,250 <br />.250 <br />.250 <br /> <br />Surface <br />Imperv. <br />(In) <br /> <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br />.1 <br /> <br />Stor age <br />Perv. <br />(In) <br /> <br />.350 <br />.350 <br />.350 <br />.350 <br />,350 <br />.360 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />.350 <br />,350 <br />.350 <br />.350 <br /> <br />Infiltration <br />Rate <br />(In!Hr) <br /> <br />.90 <br />.90 <br />.90 <br />.90 <br />.74 <br />.90 <br />.71 <br />.39 <br />.39 <br />.39 <br />.34 <br />.13 <br />.26 <br />.13 <br />.28 <br />.13 <br />.24 <br />.28 <br />.90 <br />.90 <br />.90 <br />.90 <br />.13 <br />.78 <br />.52 <br />.21 <br />.78 <br />.90 <br />.78 <br />.90 <br />.90 <br />.90 <br />.67 <br />.67 <br />.90 <br />.90 <br />.67 <br />.78 <br />.13 <br />.13 <br />.90 <br />.90 <br />.90 <br />.90 <br />.90 <br />.90 <br />.90 <br />.90 <br />