Water-quality sample collection
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River
Input Monitoring
Chesapeake Bay Watershed
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Problem
Elevated nutrient and suspended solid levels in the Chesapeake Bay
adversely affect water clarity and dissolved oxygen levels, stressing living resources in the Bay
and its tributaries. In 1987, the Chesapeake Bay Agreement called for 40% reduction in controllable
nutrients entering the Bay by the year 2000. In 2000, a renewed Chesapeake Bay
agreement was created to reinforce and redefine efforts toward these nutrient reductions. In an effort to reduce nutrients and sediments entering the Bay, management
strategies have been implemented in the tributary basins. Quantification of loads and trends is useful for assessing
the success of these management practices in improving water quality and living resource
response.
Objective
Provide concentrations and estimates of loads and trends of suspended solids, nitrogen, phosphorus,
and other selected constituents at the James, Rappahannock, Appomattox,
Pamunkey, and Mattaponi Rivers.
Relevance and Benefits
The purpose of this project is to collect and analyze water quality data and to calculate and explain load and
trend estimates of selected nutrients and suspended solids for five major river basins in the Virginia portion of the
Chesapeake Bay watershed. The stations monitored in this study are (1) the James River at Cartersville, the third
largest source of freshwater to the Chesapeake Bay at a basin area of 10,206
mi2; (2) the Rappahannock River
near Fredericksburg, the second largest contributor of flow to the Bay in Virginia, at 2,848
mi2; (3) the
Appomattox River at Matoaca, entering the James River below the Fall Line and constituting approximately 16% of
the James River basin, at 1,600 mi2; (4) the Pamunkey River near Hanover, approximately 55% of the York River
basin at 1,474 mi2; and (5) the Mattaponi River near Beulahville, approximately 35% of the York River basin at
911 mi2. Water-quality sample collection began in July 1988 for the James and Rappahannock Rivers and in July
1989 for the Appomattox, Pamunkey and Mattaponi Rivers. Base-flow samples are collected every two weeks by
both USGS and Virginia Department of Environmental Quality personnel. Approximately 20-25 high-flow samples are scheduled to be collected at each
site annually by USGS personnel. Monthly and annual loads are currently estimated using a seven-parameter
log-linear-regression model. Trends in load, flow-adjusted concentrations, and flow-weighted concentrations are
also estimated annually.
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