A Comparison of Salinity Trends vs. Water and Land Use in the Gunnison River Basin   Kenji Wright Abstract: Analysis of trends in salinity levels on the Gunnison River have determined that salinity levels have a decreasing trend over the 1970-1993 time period; however, the analysis did not distinguish any significant trends for the time periods of 1980-1993 and 1986-1993. Salinity Control Projects implemented by the Colorado River Basin Salinity Control Act began on the Lower Gunnison in 1988 with USDA initiated on-farm improvements and in 1990 with the Bureau of Reclamation's Winter Water Replacement Project. The success of the salinity control projects could not be determined by the trend analysis because of the recentness of the projects. From 1985-1995, there is an increase in the population in the Gunnison River Basin, an increase in irrigated land, but no change in the amount of water withdrawn for irrigation. An increase in the irrigated land area increases the amount of surface area exposed to evaporation, causing surface salt formation, and increases the amount of marine deposited sediments exposed to the infiltration of irrigation water. These two factors seem to suggest that salinity levels would increase until salinity control projects increased at the rate of irrigated land expansion. Key References: 1. Butler, D.L. (1996). Trend analysis of selected water quality data associated with salinity control projects in the Grand Valley, in the Lower Gunnison River Basin, and at Meeker Dome, western Colorado. Denver, CO: U.S. Dept. of the Interior, U.S.G.S. 2. Bauch, N. & Spahr, N.E. (1998). Salinity trends in surface waters of the Upper Colorado River Basin, Colorado. Denver, CO: U.S. Dept. of the Interior, U.S.G.S. 3. Dreacon, J.R. & Driver, N.E. (1999). Distribution of Trace Elements in Streambed Sediment Associated with Mining Activities in the Upper Colorado River Basin, Colorado, USA 1995-96. Archives of Environmental Contamination and Toxicology, 37, 7-18.   Return to Water Resources Papers page.