Correspondence on Bonneville Unit of Central Utah Project

Page 131

Faxogram - 3 Furthermore, there are far more water right claims for Utah Lake and Jordan River water than the supply available. For example, Kennecott Copper Corporation^uses all the water from the Lake available under its right, which is early in priority. It is estimated that by 198O about 30,000 acre-feet of low quality water from the lake will be converted for such industrial use. During the same period it is ex­pected that additional wells will be put down for an added 20,000 acre-feet annually of industrial water. It is estimated that not more than 6,000 acre-feet of high quality water will be available in Salt Lake County by about 1990 from irrigation conversions and the rights to most if not all of this water are already owned by Salt Lake City. If ground water is to be an alternative to Bonneville Unit imports for M&I use in Salt Lake County, then the average long-term ground water yield must equal that . of surface supplies. In developing the Unit plan, conjunctive use was made of available surface and ground water supplies. Frontal streams an^..present surface imports were used to the fullest extent possible, then ground water supplies (both base and peaking) were utilized to the maximum extent consistent with existing physical, legal, and economic constraints and the impact on existing rights. Those who would contend that an additional 7^,000 acre-feet of ground water can be developed in Salt Lake County without "serious adverse effects" are ignoring the en­vironmental impacts demonstrated by the USGS analog model studies. These include: .Depletion of base flows and effect on existing rights of the Jordan River in the order of 50,000 acre-feet per year. Reduction in groundwater supplies to phreatophyte (wildlife) areas.. of U0,000Aacre-feet per year. Reduction in present flowing well discharge of 15,000 acre-feet per year. Developing additional ground water would only divert the water away from the above existing uses and would require replacement supplies. Under water demand projections, we have already included utilization of 12,000 acre-feet of high quality M&I water.accruing from anticipated private development. This satisfies such demands for only 2 or 3 years. Artificial recharge of the ground water basin with Deer Creek or other storage . water is not currently practical. Better control of impounded water would be rea­lized by leaving it in surface reservoirs. Long-term forecasting techniques are not presently available to show when carry­over storage ;water is subject to spill In future years. It is easy to say that v spilled water should have been used to recharge the underground. It is presently'not-practical or economically possible to divert high flows to the underground; extensive holding ponds, desilting works, and large recharge well capacity would be required. Such facilities would operate over a very short time period each year. There is a management alternative related to the timing of.construction of Little Dell Dam and Reservoir as to before or after the Bonneville Unit-. The yield would be somewhat higher if it were constructed before the Bonneville Unit, but the costs of . ^ Faxogram - 3 Y ' «^, m