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<br />the West Fork centering. The 1 % rainflood peak flow from the frequency curve for Rico is 2,440 <br /> <br />e <br /> <br />cfs. Based on the observed rainflood record, the 1,vest Fork centering, not the East Fork <br /> <br />centering, produces reasonable results at Rico. The 1 % rainflood hydro graph at Dolores from the <br /> <br />West Fork centering also compares favorably with the Dolores flow frequency curves. Therefore, <br /> <br />the West Fork centering was used with the HMS model to generate the 1 % rainflood hydro graphs <br /> <br />for the Upper Dolores River watershed. <br /> <br />Table 17 presents a comparison between the HMS model (West Fork centering) 1 % <br /> <br />hydro graphs at the Rico and Dolores gages and the flow frequency curves for the gages. For the <br /> <br />3-day duration, the hydro graph volumes are noticeably smaller than the flow frequency curve <br /> <br />volumes. The 1 % flow hydro graphs are the result of a 2-day general rainstorm. Most of the <br /> <br />higher magnitude volumes (3 days and longer) used for the rainflood flow frequency curves are <br /> <br />for late June rain-on-Iate-snowmelt events, when melting snow contributes additional volume to <br /> <br />the falling limb of the hydro graph. <br /> <br />e <br /> <br /> Tablle 17 <br />Frequency Curves Compar'ed to HMS Model Results <br />1 % Chance Exceedence Storm (West Fork Centering) <br /> Dolores River below Rico (cfs) <br /> Peak I-day 3-day <br />Frequency HMS Frequency HMS Frequency HMS <br />Curve Model Curve Model Curve Model <br />2,440 2,290 1,590 1,210* 1,150 620 <br /> Dolores River at Dolores (cfs) <br /> Peak I-day 3-dav <br />Frequency HMS Frequency HMS Frequency HMS <br />Curve Model Curve Model Curve Model <br />11,700 11,700 6,260 7,000* 5,070 3,680 <br />* I-day represents maximum 24-hour volume <br /> <br />e <br /> <br />34 <br />