OCR Text |
Show Utah Facts states: " Upper reaches of most Utah streams carry high quality water which degrades gradually in the downstream direction. State policy is to preserve high quality in the upper reaches and to upgrade quality where necessary in downstream areas. In some heavily populated and industrialized areas tertiary treatment is expected to be a future requirement.' The water quality situation described above is generally true from both the bacteriological and chemical pollution standpoints. In the Bonneville Basin area of the Unit the water is generally of excellent quality and bacteriological or chemical pollution is not at present a serious problem. However, on Utah Lake, Jordan River, and the Lower Sevier River total dissolved solids and coliform count limit the use of these waters to irrigation or low quality industrial use. In the upper Colorado River area of the Unit chemical pollution and the effect on the lower basin uses is the greatest problem at present. Flows in the upper reaches of most streams are of excellent quality and suitable for most uses. In reaches of the lower Duchesne River irrigation diversions deplete the flows. Remaining flows consist mainly of irrigation return flows with high total dissolved solids. Natural leaching also adds salt to the system. In the Upper Colorado River Basin " natural sources are thought to contribute 50 percent of the salt load, agricultural sources IT percent, and unidentified sources 33 percent." loo a. Jordan Valley Most of the mountain front streams in Jordan Valley and the imported supply from the Provo River are of a high quality calcium bicarbonate- type water having TDS in the 120 to U00 mg/ 1 range. This water is suitable for most uses with a minimum of treatment required to render it potable. Water from some springs having covered collection works requires only chlorination. Conventional treatment of high quality surface waters of the area usually consists of sedimentation, coagulation, filtration, and chlorination. Waters of Utah Lake and Jordan River, however, are of a poorer quality calcium bicarbonate- sulfate type with TDS in the 800 to 3,000 mg/ 1 range increasing by as much as 6,000 mg/ 1 in drought years and years of maximum drawdown. They are usable only for irrigation and low quality industrial use. Due to TDS in excess of 500 mg/ 1, these waters cannot be made potable with conventional treatment. Reduction of dissolved solids to tolerable levels would require desalting- type facilities. Untreated municipal and private sewage, animal feed lot wastes, industrial plant discharges, and inadequately treated effluent 195 |