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,~` The amount of available water which naturally originates within the Bolton Draw watershed vs. the amount contributed by irrigation return flow from the trans-basin Spear Ditch diversion can be approximately quantified based on the following assumptions: 1) Surface water availability within the Bolton Draw water- shed comes mainly from spring snowmelt with negligable' quantities being contributed by other rainstorm events throughout the year. 2) According to Bernie Shafer (with the Soil Conservation Service Snow Survey Unit in Denver), the average April 1 snowpack thickness and resultant water content can be approximated in the Bolton Draw vicinity. This is accomplished by extrapolating (based on elevation dif- ferences and weather characteristics) the snow condition as compared to the known statistical averages exhibited at the Parkview Snow Station one mile south of the Willow Creek Pass summit. This station, located at 9500' elevation, has an average April 1 snowpack of 35" and a water content of 9.8". Mr. Shafer estimates that at our mine site (approximately 1000' lower in elevatior based on typical winter weather patterns, the average April 1 snowpack would be about 24" with a water content of less than 8". 3) According to Erik Wagner, Jackson County Water Commiss- ioner, the Speer Ditch has a maximum appropriation of 11.5 CFS, however, this much water is not used on the average. Mr. Wagner stated as of this writing (late July) that he estimated the present flow at the mouth of Bolton Draw to be about 1-2 CFS. Mr. Wagner had previously told (see page 110) Wyoming Fuel Company that "...Ballet Livestock irrigates land in the northeast corner of Section 22 near Bolton Draw from Speer Ditch on the average from the 10th of May to the 15th of July. Thus, the water flow in Bolton Draw terminates after the middle of July. That is, the water supply for Bolton Ditch originates at the Michigan River, in a basin which will not be affected by mining operations." This statement is generally true except during spring snowmelt when water within the Bolton Draw watershed al: supplies the draw probably from about mid April to mid May. Therefore, since the Bolton Draw watershed comprises 10.6 square miles, and in an average year is covered by 8" of water resulting from snowmelt, the average amount of avail- able water which naturally originates within the basin is given by the following expression: (10.6mi2)(640 acr2s)(0.67 ft) = 4,595 acre-ft mi -11-