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. . ...... -.J M:;- .l~) flows mg/I. flows ranged from .033 to .374 Maf and concentrations from 518 to 283' For the 1965 to 1983 post-reservoir period, the range of monthly was .11 to .16 Maf and 468 to 512 mg/1. $.; Further down stream, at Green River, Utah, the effects of Flaming Gorge Reservoir were still evident. This effect is characterized by increased flow and decreased concentration in the low-flow months, but little change in the high-flow months. January flows have changed from .10 Maf and 733 mg/l to .22 Maf and 595 mg/l. Similarly, the Aspinall Unit on the Gunnison River and Navajo Dam on the San Juan River have not significantly altered the overall flow or concentration, but have caused major changes in their seasonal variation. In general the major reservoirs from the Colorado River Storage Project have augmented low flows and reduced the concentration of low flows, but have also reduced the high flows and increased their concentration. This may have importance for irrigation, which has traditionally used water' during the high-flow period, when dissolved-solids were lowest. Flaming Gorge, Navajo, and the Aspinall Units have not as yet exhibited major changes in the total flow or dissolved-solids concentration. Lake Powell markedly reduced both flow and load during the filling period (up to 1980); however, since then flow may have returned to more normal levels. Although events throughout the Upper Basin affect the quantity and quality of water flowing into, and ultimately out of, the reservoir, the mixing and regulation of water in Lake Powell effectively control the water delivered to the Lower Basin. Effects of Salinity Control Project The record for White River near Watson was separated into pre- and post-periods to evaluate the effect of the plugging of Meeker Dome. A highly-significant annual reduction of 89 mg/l was noted after 1969, corresppnding to a reduction of 55,000 to 59,000 tons per year. The reductipn was evident in all months of the year and composed primarily of sodium chloride. Due to the short period that the Grand Valley I project has been in place, no trends were found (up through 1983). However, the four creeks where the U.S. Geological Survey has maintained records (Reed, Mack, Salt, and Adobe) show very high runoff amounts relative to their drainage area (up to 45 inches per year), with a total salt load averaging 300,000 tons per year. The analysis of ,other trend results and sources of salt loads is continuing, . .~ , ,L << ."J ,"_, "c-';^" o;,J " ',', ',',;1,' . ',-' k ,:: _ _ )l.i>'i ;li;:,"-.~'-,,;il.hcjU\j~'~