OCR Text |
Show were conducted to determine effects of increased pumping on the system. " The tests support the conclusion that a considerable increase in the use of groundwater is physically feasible. The average annual withdrawal of groundwater from pumped and flowing wells in existing centers could be increased to at least 150,000 acre- feet with no serious adverse effects. If pumping from large wells near Garfield increased in proportion to the average, water from Great Salt Lake would infiltrate the wells. This probably would not seriously affect the usability of the water in its present application of ore processing. If desired, the contamination by lake water could be avoided by limiting the increase of withdrawal from those wells. " If the annual withdrawals increased to more than 200,000 acre- feet after 1968, the aquifer underlying eastern Salt Lake City would be dewatered before the year 2020 and poor quality water from the Jordan River and from areas west of the river would contaminate wells east of the river. Thus, the practical limit of continuous withdrawals from existing pumping centers is between 150,000 and 200,000 acre- feet annually." 32 With present groundwater development at about the 125,000- acre- foot level this means that the practical limit of additional development is in the 25,000- to 75,000- acre- foot range. A figure considered reasonable and acceptable which is now being used in cooperative State Water Plan Studies by the State Division of Water Resources and Bureau of Reclamation, based on consulting with the U. S. Geological Survey, is 50,000 acre- feet per year. Of this amount 30,000 acre- feet is considered to be high quality water suitable for municipal use. The balance of 20,000 acre- feet would be low quality water suitable for heavy- industrial use. Present planning for the proposed Bonneville Unit which would meet demands to about; 1990 was done assuming independent water systems would expand their use of groundwater by about 12,000 acre- feet annually by that time. The remaining 18,000 of the 30,000 acre- feet is 191 |