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<br />basin above Dolores (D.A. = 504 sq. m1.) which compli.ments a l..te <br /> <br />summer-fall general rain storm condition (Figure 6). The distd.buU.on <br /> <br />patterns of the 1970 storm at the Pleasant Vie',,", Silverton, and Durango <br /> <br />recording precipitation gages were reviewed and ," general:Lzed distd.butf.on <br /> <br /> <br />.'as developed. Table 7 shows the SP:; hourly depths (which are 50% of the <br /> <br /> <br />P.~lP depths) and distribution that was used to calculate the Standard <br /> <br /> <br />Proj ect Flood at the Dolores gage. <br />The SPS depths for the IJest Dolores River 'J.J:ea, and the Dolores <br /> <br />River area above the confluence of the West Dolores River were calculated <br /> <br />using a drainage area adjustment: of the 504 sqU-!lre mile SPS depth. <br />A Standard Project thunderstorm was develojJed for the Lost Canyon <br /> <br />C;ceek basin. The SPS used was 50/; of a J-hour prQbable lDalximum storm <br /> <br />calculated using the procedures and curves illust:rated in the publi,cation <br /> <br />"Prob",ble Maximum Thunderstorm Precipitation Es tiJOates-Southwes'l; States." <br /> <br />The SPS. dis tribution and depths used are shol.m on, Table 7. Sev.~ral <br /> <br />distributlons were used to determine if a pattel:'n existed that liould give <br /> <br />a substantial higher computer peak discl1arge than any other disl;ribllf:ion. <br /> <br />After testing these it I,as found that tl1e loss r:-ates greatly controlled <br /> <br />the effect of any distri::ution on the m;1gnitude of the pE!ak dj.scharg'~, <br /> <br />Therefore the generalized thunderstorm distribution shown on Table 7 was <br /> <br />chosen' for use in this study. <br /> <br />9. <br />