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<br /> <br />d/' <br /> <br />storage. Investigations have shown that these two components may be <br /> <br />separately computed. The Clark method as originally presented obtained <br /> <br /> <br />. the factors for computing time elements of translation and attenu- <br /> <br />ation by analyses of observed flood hydrographs and evaluated the <br /> <br />attenuation effect by the "Muskingum Method" of routing for. <br /> <br />reservoir-type storage. We have found that the Clark method may be <br /> <br />used for developing unitgraphs for ungaged areas by evaluating the <br /> <br />translation effect by estimation of a watershed average flow velocity <br /> <br />and evaluating the attenuation effect by a relationship of attenuation <br /> <br />to total basin flow travel time. We have also simplified the routing <br /> <br />computations by adopting the routing procedure "in the "Stanford <br /> <br />Watershed Model IV" report.y <br /> <br />A Clark unitgraph is obtained by computing instantaneous discharges <br /> <br />for successive increments of basin area", translating the discharges <br /> <br />to the basin outlet and routing the discharges for storage effect <br /> <br />to evaluate attenuation. We used the following procedure to compute <br /> <br />the Clark unitgraphs in this study. <br /> <br />. 1. . A distance-area curve for each subarea was constructed. <br /> <br />Beginning at the subarea outlet, and working upstream, equally <br /> <br />spaced "contours" representing equal flow distance from the <br /> <br />outlet were drawn. Incremental areas thus delineated were <br /> <br />y"Digita1 Simulation in Hydrology: Stanford Watershed Model IV," <br />Norman H. Crawford, Ray K. Linsley; Technical Report No. 39, July 1966, <br />. Dept. of Civil Engineering, Stanford University, <br /> <br />11 <br /> <br />. .'.~... A"" __"_ _ '. '" ,,~~..". .., <br /> <br />. ~ .....~. . <br /> <br />,. "~" - - --." -". .' <br /> <br />......... <br /> <br />. <br />