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<br />the drawdown data. Slightly less than one-half of a foot of drawdown was observed <br />in well B in 24 hours. <br />Figure A-54 shows the semi-log plot of the drawdown data for observation well <br />B. brawdown data io this well also portrays two straight lines with a flatter <br />section between the two straight lines. The fit of the Neuman type curve Kv/Kh=0.01 <br />and S/Sy=0.2 is presented in Figure A-55 for the well B drawdown data. A <br />transmissivity of 17,500 gal/day/ft and a specific yield of 0.058 were obtained from <br />this match. The transmissivity of the alluvium from this well is essentially equal <br />to that obtained from well A but [he specific yield value is significantly less. <br />SUMMARY OF YAMPA ALLUVIUM AQUIFER PROPERTIES <br />i <br />The gravel pit .pump test indicates that the average transmissivity of the <br />alluvial aquifer in this area is 17,700 gal/day/f[. The horizontal and vertical <br />average permeabilities are 160 and 1.6 ft/day respectively. The most important <br />storage value for an unconfined aquifer is the specific yield and an average value <br />of 0.13 was determined from this test. <br />i <br />A-26 <br />REVISED FEB 13'7 <br />