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,~ e",.) ...... ~ 0) was assumed that no change in the salt load versus flow relationship had . occurred. The San Rafael River contributes only 1 percent of the water and 2 per- cent of the total salt load to the river system. Because the river's con- tribution to the total infow is relatively very small, only a brief analysis of the relationship was made. This analysis did not reveal an obvious change in the relationship. Inflow From Lees Ferry to Grand Canyon. - Analysis of the ri ver reach from Lees Ferry to Grand Canyon for the period 1941-1976 was made to deter- mine if a change in salt load has occurred in this reach. The studies indicate a change in the salt load relationship beginning in 1955. For a virgin flow of 14 million acre-feet per year, the salt load based on the 1955-1976 relationship is 243,000 tons less than when based on the 1941-1976 relationship. Salt Gain or Loss in Lake Powell. - The 1975 and 1978 salinity projec- tions assumed there were no gains or losses of salt fn Lake Powell. A mass-balance analysis of historical inflows into and outflows from Lake Powell for the 1963 through 1976 period, assuming complete mixing of inflows with water already in the reservoir, indicated an average annual loss of salt in the reservoir of 135,000 tons. The analysis also showed a relationship between salt gain or loss and change in reservoir water level. This rela- tionship indicated a net loss of salt for reductions in storage and for increases in storage of less than 1.5 million acre-feet per year and a net gain of salt for increases in storage greater than 1.5 million acre-feet per year. Because the relationship was based on the period during which Lake Powell was in its initial filling cycle (only 4 years during the 1963 through 1976 period experienced a reduction in reservoir storage), it was concluded, . . 16