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_ during the summer months. The short growing season precludes growing of many <br />crops such as corn. In the Williams Fork River an even high proportion of the <br />water used is for agricultural activities. <br />The Trapper mine drainages are all ephemeral with runoff mainly from snow melt. <br />Some summer thunderstorms produce runoff for short periods. However, during the <br />later period of the 1981 through 1986 permit term, perennial runoff has occurred <br />in the East Pyeatt and Middle East Flume Gulch drainages. This is due to water <br />storage in alluvium and seeps originating in the upper bedrock aquifers. The <br />remainder of this section contains information on the ephemeral drainages of the <br />mine area. <br />Annual water yield from the permit area is estimated to be approximately one inch <br />of runoff per unit area. This figure is corroborated by two sources. The Upper <br />Colorado Region Comprehensive Framework Study (1971) used data collected from <br />1914 to 1965 and estimated average annual runoff for the Craig area of less than <br />1" (50 ac-ft/mit) (Woodward Clyde, 1977). A water -yield map prepared by the <br />Colorado Water Conservation Board (1969) also provides data that compare favor- <br />ably with this figure. Table 2.7-12 gives drainage acreages of tributaries <br />within the permit area and their estimated annual yields based on the figure 50 <br />ac-ft/mit, Map M30 shows the drainage area divides in the Trapper Mine Area. <br />Baseline data have been collected in the vicinity of the mine -plan area since <br />1974. Locations of the baseline water -quality monitoring sites are shown in Map <br />M30. Flume, Pyeatt and No Name gulches were equipped with 4', 6' and 4' width <br />Parshall Flumes, respectively. Since 1984, these sites are equipped with 1.0' <br />width Parshall Flumes. Johnson Gulch was monitored downstream of the proposed <br />mine plan area by using a rated section (site S-4). These stations were <br />monitored continuously with Stevens Type F water -level recorders. Flume sizes <br />were selected based on theoretical 25 -year recurrence interval peak flow rates. <br />The remoteness of flume sites prohibited their stilling wells, which, <br />i 4W FEB 13 'RT <br />