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<br />C'J <br /> <br />'o::t' <br />N <br />C <br /> <br />'-' <br /> <br />interpreted as galnlng flow from irrigation return flow (surface <br />runoff and deep percolation) and natural ground-water discharge. The <br />reach below Bunkerville again showed no appreciable loss or gain. The <br />Riverside reach, which includes the Riverside Irrigation District and <br />a portion of phreatophytes, showed a gain at certain seasons, that may <br />be attributable to irrigation return flow. The Mormon ~lesa reach <br />further downstream shows a general loss except in January, February, <br />and April. This can be attributed to phreatophyte consumptive use and <br />related stream losses. <br /> <br />Twenty-five water quality samples were taken <br />analyses during the study. The Virgin River water was <br />calcium sulfate type. <br /> <br />for standard <br />found to be a <br /> <br />Ground Water <br />The composition of the water bearing zones under the valley, <br />based on driller's reports, is a combination of sand, gravel, and <br />cobbles, with some clay. The majority of the existing wells are <br />completed at depths of between 50 and 200 feet. The distance from <br />land surface to the zone of saturation ranges from less than 5 feet <br />near the river to over 300 feet at a distance of 3 miles to the south- <br />east of the river toward the Virgin Mountains. The depth to water is <br />over 200 feet in an area 5 miles north of the river in Toquap Wash. <br />The water table is generally less than 150 feet below land surface <br />within 1 mile of the river. Ground water also occurs as the spring <br />flow in the Littlefield area and upstream. <br /> <br />After the evaluation of 88 well driller's reports, 27 existirlg <br />wells were selected for water level monitoring. In addition, 9 <br />sha 11 ow monitori ng well s were constructed for observati on of water <br />table fluctuation and the water quality associated with agricultural <br />and phreatophyte areas. At each new site, two shallow wells were con- <br />s tructed--one by dri v i ng a sand poi nt 15 to 20 feet be low the 1 and <br />surface. The second was a 6-inch well, hand augered to 4 feet below <br />the water table. The second well was fitted with a continuous water <br />level recorder. <br /> <br />21 <br />