| OCR Text |
Show 1. Water Quality A study published by the U. S. Department of Health, Education and Welfare? was conducted to assess the probable effects of Unit construction and operation on water quality in local streams and lakes. The benefits or harm resulting from changes in water quality were ascertained and the need was examined for regulation of streamflow for the purpose of water quality control in the principal streams affected. From more than 1,200 water samples taken at about 100 collection points, the chemical quality ranges of Bonneville Unit water sources were estimated for historical and future conditions under Unit operation. The water quality estimated at key points with respect to Unit operation is shown in Table C- 29. Table C- 29 shows that with relatively pure water diverted for Unit purposes from the headwaters of Duchesne River, the remaining flows below the town of Duchesne would sometimes have a higher concentration of dissolved solids than in the past. The greatest concentration would occur during the winter months when flows are low and the water is not being used for irrigation. Nonirrigation season water divertible near Duchesne for storage in Midview Reservoir would be monitored to make sure that the water diverted would be suitable for irrigation. The concentration of dissolved solids at the head of Myton Townsite Canal, planned to be the lowest important diversion point on the river, would be higher in the spring but lower in the late summer than in the past. The spring season concentrations would still be well within useful limits and the year- round quality of the water at that point would be improved by the Unit. The Unit would not affect the quality of the water at Strawberry Reservoir or in Provo River. The water quality of both of these sources is good. ^ Unit operation would improve the quality of the water in Spanish Fork River at Castilla during the nonirrigation season. The concentration of dissolved solids in Mona Reservoir and Utah Lake would be decreased by the Unit partly as a result of good quality water received from Strawberry Reservoir. In Utah Lake where the water quality would also be improved by the diking of Goshen and Provo Bays, the reduction of dissolved solids would average about 30 percent but would reach 75 percent reduction at the lowest lake levels. In addition to reducing the loss of pure water by evaporation, the Goshen Bay Dike would prevent saline water presently originating in the bay from entering the lake. Saline deposits south of the bay, shown on Figures C- l6 and C- 17, illustrate the potential for salt being washed into the bay. A study by Dr. J. Barnes of Brigham Young University entitled The Effect of the Proposed Goshen Bay Dike on the Benthos of Utah Lake in Relation to Water Quality70has been in progress for one year. 393 |
