The hydrologic system of the Sevier Lake area, at the terminus of the Sevier Lake drainage basin in west-central Utah, was studied during 1987-88 to determine baseline hydrologic conditions prior to anticipated development. Sevier Lake was reestablished during 1983-87 on the normally dry playa as a result of record volumes of surface-water runoff, but the lake was receding during the study. In June 1985, the lake reached a maximum depth of about 13 feet, with a water-surface altitude of 4,527 feet above sea level.
The basin-fill aquifer includes a coarse-grained facies at higher altitudes of the alluvial slopes, and a fine-grained facies at lower altitudes around Sevier Lake. Water levels indicate a potential for lateral groundwater movement away from the lake and toward the northwest, west, and south.
Transmissivity of the coarse-grained facies, determined from one well, was 4,120 feet squared per day. Transmissivity values for the fine-grained facies ranged from 1 X 10-3 to 5 X 10-2 foot squared per day, determined from slug tests of shallow wells near the shoreline of the lake, and 5.2 feet squared per day determined from a well in the lakebed.
The predominant constituents of water sampled in the Sevier Lake area are sodium, sulfate, and chloride. The concentration of dissolved solids ranges from 480 to 120,000 milligrams per liter. Smaller concentrations of dissolved solids were determined for water from wells completed in the coarse-grained facies, and larger concentrations were determined for water from wells completed in the fine-grained facies.
