TY - Generic T1 - Potential effect on water project yield of changed snowmelt runoff patterns T2 - 62nd Annual Western Snow Conference Y1 - 1994 A1 - Roos, M. KW - Agricultural demand, Runoff patterns, Snowmelt AB - One of the potential changes of global warming would be a shift in runoff patterns in temperate zone mountains with less spring snowmelt and more direct winter rain runoff. The Mokelumne River, located in the central Sierra Nevada range of California, was examined to see how this shift in runoff pattern would affect water supply yield. The shift reduced April through July runoff by an average of 28 percent with a corresponding increase in winter runoff, some of which had to be released for flood control purposes. However, the loss in water project dependable urban supply was only 1 to 3 percent. Part of the reason for the small change was the fact that total reservoir storage capacity exceeds average annual runoff of the basin. Another factor was the relatively uniform monthly demand, which generates a smaller dry season draft than an equivalent annual agricultural demand. The level of demand also has an influence; water systems operating beyond their firm yield limit will be more stressed by changing runoff. JF - 62nd Annual Western Snow Conference T3 - Proceedings of the 62nd Annual Western Snow Conference PB - Western Snow Conference CY - Sante Fe, New Mexico UR - sites/westernsnowconference.org/PDFs/1994Roos.pdf ER - TY - Generic T1 - Possible climate change and its impact on snowmelt and water supply in California T2 - 58th Annual Western Snow Conference Y1 - 1990 A1 - Roos, M. KW - Climate change, Global warming, Greenhouse effect, Sea level rise, Snowmelt runoff, Water projects, Water resources AB - Global Climate modelers are forecasting relatively large future climate changes, with warming of 2 to 5 degrees C. The changes, if they do come to pass, would have profound impacts on California's water resources. A shift in runoff patterns would be expected with less spring snowmelt and more winter runoff. This shift will make it difficult to fill major multi-purpose reservoirs once the flood season is past, with losses in water yield and hydroelectric power. Also the predicted rise in sea level may cause problems with water transfer in the Sacramento-San Joaquin Delta. Increased risk of levee failures in the Delta and a potential increase in ocean salinity intrusion could affect water supplies of the central and southern portions of California. JF - 58th Annual Western Snow Conference T3 - Proceedings of the 58th Annual Western Snow Conference PB - Western Snow Conference CY - Sacramento, California UR - sites/westernsnowconference.org/PDFs/1990Roos.pdf ER -