7807 - Laserfiche WebLink

Home Browse Search

c. Duchesne River near Randl tt Utah - GS number -09302000. The gauge has been in operation from 1943-1995. The gauge is reflective of the runoff from 4247 square miles above the gauge. The average annual runoff past the gauge is 398,900 acre-feet. The records at the gauge are generally poor. There are large diversions for irrigation, including transmountain diversions to the Great Basin through the Duchesne and Strawberry Tunnels, Hobble Creek ditch, the Strawberry River, and Willow Creek ditch above the gauge. The following reservoirs impact the flood flows that pass the gauge: Reservoir Name Storage Capacity acre-feet Year First Started Storing Water -Strawberry 1,106, 500 1912 Starvation 152,310 1969 Moon Lake 35,760 1937 Upper Stillwater 32,000 - The combination of reservoir storage, transbasin diversions, and irrigation diversions has a great impact on the larger peak flows. It is probable that the smaller peak flows will result from reservoir releases and some flow from areas located below the dams. The annual peak flows vary from a high flow of 11,500 ft3/s on June 20, 1983, to the lowest annual peak of 314 ft3/s on July 8, 1992. The earliest time that the peak flow has occurred during any water year is March 22nd (1988). The latest the peak flow has occurred is September 30th (1993). In general, the peak rate of runoff occurs as the result of snowmelt with a large amount of the peaks occurring in late May and June. Table 5 summarizes the recorded flows for the Duchesne River near Randlett, Utah, used in the analysis. Table 6 summarizes the results of entering the yearly peak flows into the FREQY computer model,and letting the model compute historical recurrence level flood peaks following the log Pearson Type III methodology, and guidelines in Technical Bulletin 17B. It is probable that this data are high on the upper end of frequency curve, since the peak flows shown prior to 1969 do not reflect regulation by Starvation Dam. Figure 3 shows a plot of the historical flow frequency curve for the Duchesne River near Randlett, Utah. 12