New Publication:
Spatial and Temporal Trends in Runoff at Long-Term Streamgages within and near the Chesapeake Bay Watershed
This study by the U.S. Geological Survey, prepared in cooperation with the Virginia Department of Environmental Quality, analyzes long-term streamflow data within the Chesapeake Bay watershed and surrounding area. Data from 30 streamgages near and within the Chesapeake Bay watershed were selected from 1930 through 2010 to identify trends in streamflow. Trend slopes were calculated as percent change per decade. Trend slopes for three runoff statistics (the 7-day minimum, the mean, and the 1-day maximum) were analyzed annually and seasonally, as well as spatially and temporally. The spatial results indicate that trend slopes in the northern half of the watershed are generally greater than those in the southern half. The temporal analysis was done by splitting the 80-year flow record into two subsets: 1930 through 1969 and 1970 through 2010. Results indicate that the period 1930 through 1969 was statistically different from the period 1970 through 2010.
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New Publication:
South Fork Shenandoah River Habitat-Flow Modeling to Determine Ecological and Recreational Characteristics during Low-Flow Periods
The ecological habitat requirements of aquatic organisms and recreational streamflow requirements of the South Fork Shenandoah River were investigated by the U.S. Geological Survey in cooperation with the Central Shenandoah Valley Planning District Commission, the Northern Shenandoah Valley Regional Commission, and Virginia Commonwealth University. Physical habitat simulation modeling was conducted to examine flow as a major determinant of physical habitat availability and recreation suitability using field-collected hydraulic habitat variables such as water depth, water velocity, and substrate characteristics. Fish habitat-suitability criteria specific to the South Fork Shenandoah River were developed for sub-adult and adult smallmouth bass (Micropterus dolomieu), juvenile and sub-adult redbreast sunfish (Lepomis auritus), spotfin or satinfin shiner (Cyprinella spp), margined madtom (Noturus insignis),and river chub (Nocomis micropogon). Historic streamflow statistics for the summer low-flow period during July, August, and September were used as benchmark low-flow conditions and compared to habitat simulation results and water-withdrawal scenarios based on 2005 withdrawal data.
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