OCR Text |
Show 53 a Lake elevation of 4,205 feet. If the Lake is lower, less groundwater will enter the Lake and more will be consumed by evapotranspiration. Another small area at the north end of the Oquirrh Mountains contributes about 750 acre- feet of underflow to the Lake, bringing the combined total to about 4,000 acre- feet ( Hely et al., 1971). Chemical Quality of Groundwater-- The quality of the water within the principal aquifer flowing northward from the Jordan Valley toward the Lake varies widely. In the northeastern part, the water is of good quality, having a dissolved solids content of 250- 500 mg/ 1. However, in the rest of the area bordering the south shore of the Lake, most of the water contains 2,000- 5,000 mg/ 1, while the water contains 5,000- 20,000 mg/ 1 in an area northwest of the tailings pond. Tooele Valley Groundwater The Tooele Valley groundwater system is bounded on the south by South Mountain, on the east by the Oquirrh Mountains, and on the west by the Stansbury Mountains. Most wells in the northern part of Tooele Valley tap a principal artesian aquifer. The top of this aquifer is at various depths, ranging from 50 feet to 350 feet, because the aquifer is offset vertically by faults. Discharge to the Great Salt Lake- Gates ( 1965) states that the amount of water moving into the Lake from Tooele Valley cannot be calculated because the necessary hydrologic data ( transmissibility and hydraulic gradient near the Lake shore) is not known. Quality of Groundwater-- Most of the north- central part of the principal aquifer in Tooele Valley contains 800- 1,300 ppm dissolved solids |