OCR Text |
Show systems in the preparation of groundwater budgets. To derive meaningful estimates of the groundwater supplies, the Bureau has attempted to prepare budgets which break down the confined and unconfined aquifer systems in areas pertinent to the Unit. Tables B- 6 and B- 7 present groundwater budgets for Salt Lake and Utah Counties. These budgets show the sources and quantities of recharge and discharge for both the shallow and the confined aquifer. Some of these estimates are tentative because they are based on preliminary results of studies not completed. ( l) Present Use ( a) Salt Lake County - Jordan Valley Approximately 126,000 acre- feet of the groundwater supply are presently being utilized annually. Of the total 117,000 acre- feet are withdrawn from the confined aquifer. The remaining 9,000 acre- feet come from natural discharge from the shallow aquifer. About 55 percent of the 212,000 acre- feet annual recharge to the confined system is presently being withdrawn and used from wells and springs. The remaining k5 percent is being discharged naturally to Great Salt Lake and to the shallow water table by upward leakage. Some of the discharge to the shallow water table finds its way into the Jordan River. The remainder is consumed by phreatophytes and lost through evapotranspiration. ( b) Utah County About 73,000 acre- feet of groundwater are withdrawn by wells each year in Utah County. Of this amount U0,500 acre- feet, 21,000 acre- feet, and 11,500 acre- feet are discharged by wells in north Utah Valley, south Utah Valley, and Goshen Valley, respectively. Only 500 acre- feet of the total are withdrawn from the unconfined aquifer. An additional 55,000 acre- feet are discharged to Utah Lake by springs within the lake, by upward leakage into the lake, and by some springs located at the edge of the lake. Well discharge accounts for slightly over half of the recharge to the confined aquifer systems. Recharge and discharge are in equilibrium in north and south Utah Valleys but discharge exceeds recharge by about 7,600 acre- feet in the Goshen Valley. Discharge is nearly twice as great as recharge in Goshen Valley. ( c) Juab Valley A complete budget has not been prepared for Juab Valley. However, from the data presented in Groundwater Resources 186 |