Instant Information about Water Conditions: Ask the River to Text You a Water Alert!!
(Press Release May 17, 2010)
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New Publication:  Comparison of Two Regression-Based Approaches for Determining Nutrient and Sediment Fluxes and Trends in the Chesapeake Bay Watershed

This report documents the comparison of two multiple regression approaches, ESTIMATOR and WRTDS, for the determination of nutrient and sediment fluxes in the Chesapeake Bay watershed. Discharge, nutrient, and sediment data collected from 1985 through 2010 at the RIM stations on the Susquehanna, Potomac, James, Rappahannock, Appomattox, Pamunkey, Mattaponi, Patuxent, and Choptank Rivers were used to construct ESTIMATOR and WRTDS models for predicting daily constituent concentrations and fluxes. ESTIMATOR and WRTDS discrete flux estimates were compared to direct observations of flux at each of the nine RIM stations to determine the accuracy and bias associated with each model. Annual estimates of nutrient and sediment flux were compared to determine the average difference in annual fluxes generated by ESTIMATOR and WRTDS. Finally, this report provides trends in WRTDS-derived annual nutrient and sediment fluxes, represented as the flow-normalized annual flux, for the periods 1985–2010 and 2001–2010.

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.