Stream-groundwater Interactions along Streams of the Eastern Sierra Nevada, California: Implications for Assessing Potential Impacts of Flow Diversions

2 Assistant Professor of Environmental Planning, Department of Landscape Architecture, University of California, Berkeley, California. Abstract: One of the most fundamental hydrologic determinations to be made in assessing the probable impacts of flow diversions on riparian vegetation is whether flows are gaining or losing water to groundwater in the reach of interest. Flow measurements on eight streams in the Owens River and Mono Lake basins show that streamgroundwater interactions can produce substantial changes in flow; these changes can vary among streams, along one stream, and in different seasons. Over one stream reach, autumn baseflow increased nearly three-fold from groundwater contributions; in another, summer flow decreased 50 percent.