Laserfiche WebLink
Calculation and tabulation of incremental rainfall amounts are detailed in • <br />Tables 3 and 4. As.can be seen from Table 6, the Probable Maximum <br />Thunderstorm Flood Hydrograph, the one hour rainfall is anticipated to be <br />6.93 inches. The peak flow is estimated to be 10,600 cubic feet per <br />second, and the inflow volume is anticipated to be 1,027 acre feet. <br />Determination of the Probable Maximum General Storm was also in accordance <br />with procedures detailed in the "Design of Small Dams". Since the subject <br />reservoir is located in Probable Maximum General Storm Zone B, the maximum <br />6 Hr. point rainfall value is estimated to be~3.3 i-fiches. The 18 hour <br />` _ , __, <br />probable maximum basin rainfall was determined to b~ 6.l~inches. Details <br />of determination of probable maximum general storm data are illustrated in <br />Table 4. <br />r , <br />U <br />Determination of the hydrologic complex number for the probable maximum <br />general storm is similar to that presented in preceding paragraphs, with <br />the complex number for Antecedent Moisture Conditions II~ermined to be <br />84. <br />As may be seen in Table 7, rainfall is estimated to be 6.17 inches at 18 <br />hours. The peak flow is estimated to be 2590 cubic feet per second, and <br />total inflow volume is estimated to be 1810 acre feet. <br />Since snowmelt runoff was also determined to be significant for water shed <br />planning, a similar basin study of probable snowmelt runoff was performed. <br />Results of snowmelt determination indicate that a maximum snowmelt runoff • <br />equal to 245 acre feet per day could be expected. <br />VI-12 <br />