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Partial records are available for the years 1910-1912 for a USGS station on Trout <br />• Creek near Pinnacle, Colorado, about five miles upstream from the confluence of <br /> Little Trout Creek. The annual runoff in 191 I from 27 square mile was estimated <br /> to be 18,460 acre-feet which converts to 1.07 feet of runoff. A five year average <br /> annual runoff volume was estimated To be 19,840 acre-feet from records of a station <br /> measuring the runoff from I6 square mile of the Trout Creek watershed. These <br /> records included an extremely wet year (1957), however. Disregarding the 1957 <br /> record, the mean runoff was estimated at 17,600 acre-feet which translates to 1.7 <br /> feet of runoff on a unit area basis. <br /> Probably the best estimate of the average annual runoff from the Trout Creek <br /> watershed above TR-b is I.I feet over an area of 53.28 square miles. This value of <br /> runoff translates to 37,500 acre-feet/year or an annual mean daily discharge of 52 <br /> cfs. Annual mean minimum discharge is estimated to be about 10 cfs. This base <br /> flow occurs during the late summer and persists through the winter until spring <br /> runoff begins. <br /> Undoubtedly, the high watershed yields suggested by the above scattered <br /> records result from the large snow accumulations in the upper part of the watershed. <br /> The steep slopes and relatively small potential evapotranspiration are also con- <br />• tributing factors. The yield from the lower part of The watershed is substantially <br /> less than the mean values given in the above paragraphs. McWhorter, et al., (1979) <br /> estimate the average 1974-1975 runoff from gaged portions of The southern part of <br /> the Edna Mine to be 0.44 feet. The rouge of measured runoff from the gaged <br /> portions was from 0.17 to 0.76 feet. The maximum value was obtained from the <br /> highest portion of the Edna Mine on an area with a dominant north aspect. Runoff <br /> from the Moffat Area of the Edna Mine is expected to be on the order of 0.4 feet <br /> per year since the mean elevation of the Moffat Area is some 400 feet less than that <br /> of the south end of the permit oreo and the dominant aspect is more conducive To <br /> evapotranspiration. Partitioning of total runoff into overland flow and subsurface <br /> com ponenis is discussed in the section dealing with the hydrologic balance. <br /> There are no gaging records available on Oak Creek other than those <br /> generated in this study. The 67 weeks of data at station OK-a, beginning on <br /> SeptQmber 24, 1979, yield an average daily discharge over the period of record of f5 <br /> cfs. This mean was computed by extrapolating the late fall discharge through the <br /> 13 week period from December 12, 1979, to March 9, 1980, during which the stilling <br /> well was frozen. A mean discharge of IS cfs represents 10,860 acre-feet/year of <br />• runoff or 0.62 feet over the watershed of 27.35 square mile above station OK-a. <br /> Revised 7-81 2.5-14 <br />