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<br />t:';) <br />~'I"') <br />t'l") <br />N <br /><::> <br />o <br /> <br />in a channel that had been scoured in the underlying Muddy CI'eek <br />Formation. The Muddy Creek Formation consists of relatively imperme- <br />able mudstone and claystone. <br /> <br />The right abutment, not shown in Figure 2, was to have been <br />delineated by a shallow, hand-dug test pit approximately one "well <br />spacing" from Well VID-104. However, the pit was not dug because of <br />the abandonment of the proposal to construct a barrier. However, the <br />approximate contact has been inferred on the figure. <br /> <br />An aquifer pump test was conducted between October 9 and 11, 1978 <br />on production Well VID-102. Test pumping began at VID-102 at 8 a.m. <br />on October 9 and continued for 30 hours at a rate of 611 gallons per <br />minute (ga1/min) until 4 p.m. on October 10. The maximum drawdown was <br />16 feet and the specific capacity was 38 gal/min per foot of drawdown. <br />Recovery data were gathered for approximately 45 hours after the pump <br />was shut off. Note that the average discharge is the average of all <br />readings during the test and is 10 percent higher than that determined <br />from the totalizer. <br /> <br />The aquifer test data were analyzed using the Jacob Modified <br />Nonequilibrium Formula [6]. The presence of impermeable boundaries <br />was indicated in all observation wells as shown in Figure 2. This <br />boundary is believed to be the contact between the stream alluvium and <br />the Muddy Creek Formation. The following transmissivities were calcu- <br />lated at each of the observation wells; VID-101, 2.77 square feet per <br />second (ft2/s); VID-103, 2.49, ft2/s; and VIO-104, 4.16 ft2/s. <br />Recovery data were not analyzed due to the presence of boundaries. <br />The calculated value of storage coefficient was as follows: Well <br />VID-101, 0.011, and Well VID-104, 0.016. The value of storage <br />coefficient if calculated at Well VID-103 would be anomalously 10~1. <br />These results indicate the highly transmissive semi confined nature of <br />the stream alluvial deposits. <br /> <br />The underflow within the Virgin River was estimated based on the <br />application of the one dimensional form of Darcy's La~1 as follows: <br /> <br />16 <br />