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Show only way to increase culinary water use of Wasatch Range streams would be to provide treatment plant capacity equal to the peak runoff during periods of time when runoff flow rates can be absorbed by municipal water demands. The peak monthly runoff from all of the Wasatch Range streams is about 40,000 acre- feet. This translates to 435 million gallons per day ( mgd). At the present time, the capacity of treatment plants on the east side of the valley is 233 mgd. These east- side treatment plants ( City Creek, Parley's, Big Cottonwood, Metropolitan, Southeast Regional and Draper) are currently being used to treat the mountain stream runoff. In addition to these facilities, there is the Jordan Valley treatment plant located in Bluffdale. This facility currently has the capacity to treat 180 mgd with the potential to enlarge to 255 mgd in the future. The total current treatment capacity for the basin is 413 mgd with the potential to enlarge to 540 mgd ( see Table 9- 6). The valley's water treatment plants have sufficient capacity to treat and use more of the outflow from the Wasatch Range streams. But a tremendous cost would be incurred to convey the short duration flows across the valley to the Jordan Valley treatment plant. Furthermore, since the Wasatch Range's peak runoff occurs in May, it does not match up with the valley's peak demand which takes place in July and August. Consequently, substantial storage would still be necessary to effectively develop additional water from the Wasatch Range streams. Table 9- 6 WATER TREATMENT FACILITIES Jordan River Basin Treatment Plant Current Planned \ Capacity Enlargement ( mgd) ( mgd) City Creek 15 . Parley's 40 5 Big Cottonwood 40 - Metropolitan 113 37 Southeast Regional 20 10 Draper Irrigation Co. 5 - Jordan Valley 180 75 Total Capacity 413 127 ^ 9.5.3 Develop Additional Groundwater It is generally believed the Salt Lake Valley groundwater basin is fully appropriated. ( For more information on groundwater, See Section 19.) Plans to develop additional groundwater sources in the Salt Lake Valley are being considered, but this will be done on a very limited basis and monitored closely by the Division of Water Rights. At the present time, the State Engineer as well as many other groundwater experts believe the current level of groundwater withdrawals is approaching the safe yield levels for the valley. Groundwater recharge data show significantly more water in the groundwater basin than is currently being withdrawn. The concern, however, is that much of the groundwater recharge is of poor quality. The high quality groundwater area designated in the state's Interim Groundwater Management Plan as " Management Area Number 1" ( See Figure 19- 3) is located on the east side of the valley, primarily between the Jordan River and the Wasatch Range. Current belief that further groundwater withdrawals in this area could result in the intrusion of poorer quality water from the west or shallow aquifer into the principal aquifer, thus contaminating it. The U. S. Geological Survey, jointly with the Division of Water Rights, conducted a groundwater study for the Salt Lake Valley that was published in 1996 and should help the State Engineer set the final limits for groundwater withdrawals. 9.5.4 Artificial Groundwater Recharge Another possible means of developing surface water flows from mountain streams would be to store excess flows in the groundwater aquifer for later use. The Salt Lake County Water Conservancy District undertook a demonstration groundwater recharge project in southeast Salt Lake County during the 1990 to 1994 period. The demonstration project recharged the aquifer by injection with about 2,650 acre- feet of water. One of the principle concerns with the project was protecting the quality of the principal aquifer that serves as a major source of municipal water. The approach taken is to treat the injectate to drinking water standards and conduct extensive water quality monitoring. The project was set up to determine how much of the injected water can be recovered. Based on the success of the demonstration project, the Salt Lake County Water Conservancy District submitted a groundwater recharge proposal for funding under the Central Utah Project Completion Act. The proposal has been funded and construction is underway. When completed, the project will produce an average of 5,800 acre- feet of 9- 8 |
