Laserfiche WebLink
<br />- 18 - <br /> <br />t <br /> <br />As mentioned previously, storm-producing events in the Blue <br />River basin can come from either a snowmelt condition or a <br />cloudburst or thunderstorm in the basin. Both conditions <br />were investigated and the type of activity producing the <br />highest runoff for the recurrence interval being investi- <br />gated was chosen as the design runoff for that interval. <br /> <br />The peak discharge from the snowmelt condition occurs <br />primarily in mid-June and was determined by preparing flow <br />frequency curves from past streamflow records. Considera- <br />tion was given to climatic conditions as they relate to <br />snowmelt and to the runoff characteristics of the basin. <br />Flooding derived from cloudbursts or thunderstorms occurs <br />primarily after the middle of June and usually during July <br />or August. Due to the lack of available precipitation data <br />in the basin, it was not possible to evaluate major thunder- <br />storm events that had occurred in the past. Because of the <br />lack of data, synthetic storms were derived from statistical <br />analysis of rainfall data presented in Technical Paper 40 <br />of the U.S. Department of Commerce, Weather Service. It was <br />found that the runoff generated from the snowmelt gave <br />higher peak discharges for the frequent runoff events, such <br />as the 10-year, whereas the runoff from a cloudburst type <br />storm gave higher peak discharges for the Intermediate <br />Regional and Standard Project Floods. Peak flows for the <br />four recurrence interval floods are shown in Table 3 for <br />selected locations along the Blue River: <br /> <br />~ <br /> <br />Leonard Rice Consulting Water Engineers, Inc, <br />