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<br />Majcl!' rainfall events recorded are included jin Table 1. <br />The NWS data'agrees closely with that of the UWUA, although such are <br />avai'lable for only' a 27 year interval. <br />C. Rain on Snow <br />An examination of the 54 years of y'ainfall records available <br />indicates that during this record period, no significant amount of I"ain has <br />fallen on a snowpack. Generally, any significant snowpa:ck has meltE!d from <br />most of the basin by the time precipitation fans as rain. TherefOl"e, in <br />vie~1 of the geographic limits to snowfall in the bas'in, and the lon~l period of <br />recerds indicating that no significant rain hilS fallen on snow, it 'is concluded <br />that the f'looding effect of rain on snow for this area will be minOl'. <br />D. Frequency Analysis <br />Three data sources of rainfall WerE! used: the records of the UWUA, . <br />tho~:e of the NWS, and information obtained from the NOAII atlas. Statistical <br />analysis of the NWS and UWUA data was performed, using the method outlined <br />by L R. Beard in Statistical Methods in HydY~Q..!.2.91. (U.S. Army Crops of Engineers, <br />1962) to statistically' distribute the data points 1'01" the entire period of <br />rece I'd-keeping to correspond with recurrence 'i nterva'/ py'obabil iti es. Fi sher- <br />Tippett Type I and Log Pearson Type III statistical distributions were then <br />computed to determine the best relationship. The Fisher-Tippett Type I <br />distribution better fit the data, and, additionally, provided greatE!r con- <br />servatism. It was therefore selected to define the rainfall frequency <br />relationship. <br />The NOAA data was developed using the Fisher-Tippett Type I distribution <br />as w=ll. However, for the NOAA atlas, on'ly the previous 15 years data was <br /> <br />6 <br />