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<br />II 1-8 <br /> <br />1. sub-basin area (sq. mi.) <br />2. sub-basin length (mile) <br />3. sub-basin length to centroid (mile) <br />4. Cp and Ct value <br />5. sub-basin slope <br />6. impervious depression storage (0.10 inches) <br />7. pervious depressions storage (0.30 inches) <br />8. percent impervious cover <br />9. infiltration (1/2 in/hr, constant value) <br />A sample output from the program is shown in Table 111-3. The output also <br />includes a point plot of the unit-hydrograph storm hydrograph, total incremental <br />precipitation and excess incremental precipitation. <br />4. Flood Routing <br />The process of combining the hydrographs is defined as flood routing, which <br />included channel routing, reservoir routing and hydrograph separation procedures <br />for special application of flow splitting (separation of channel). The results <br />of the flood routing for the existing and future development conditions are <br />presented in Tables 111-4 and 111-5 as design flow values. <br />Storm hydrographs for several of the critical design locations were plotted <br />for the future flow conditions and are also presented in Figures 111-3 to 111-8. <br />The Muskingum method of channel routing was used in this analysis, and a <br />sample computer output is shown in Tables 1II-6a and 1II-6b. Due to the narrow <br />channel and velocity of flow, a minimal amount of peak flow attenuation was <br />obtained (less than one percent). <br />Reservoir routing was used to determine the peak rates of outflow from the <br />existing dam and outlet structure of Hidden Lake and Bates Lake. The procedure <br />was also used to size the improvements to Hi dden Lake as well as the desi gn of <br /> <br />any proposed detention facilities. <br /> <br />, <br /> <br />f <br /> <br />> <br />