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Potomac Water Quality Monitoring Project

Streamflow and Water Quality Monitoring in Support of Watershed Model Development, Potomac River Basin

    WRD PROJECT #: MD151
    PROJECT CHIEF: Majedi, Brenda Feit
    BEGIN DATE:    01 July 2000
    END DATE:      31 December 2002

Project Summary


Elevated concentrations of nitrogen and phosphorus in surface and ground water in the Potomac basin often result from human activities such as manure and fertilizer application (The National Water Quality Assessment (NAWQA) Program,
Click the image above for an enlarged view of the Priority Sites map (784 K).
Potomac River Basin study unit, 1992-95). The monitoring program proposed here is designed to support development and calibration of a Hydrologic Simulation Program-FORTRAN (HSPF) watershed model of the basin that may be used to assess the effects of point and nonpoint nutrient and suspended sediment sources on water quality in the Potomac River.


The U.S. Geological Survey (USGS) has responsibility for four objectives in the overall monitoring program designed to support the development and calibration of a watershed model for the Potomac River Basin:

  1. Start and operate a new continuous stream-gaging station, and restart and operate one currently inactive continuous gaging station;
  2. Establish nine new water quality monitoring stations;
  3. Plan, coordinate, and oversee sample collection, using USGS and Maryland Department of the Environment (MDE) staff;
  4. Manage all project data, and plan and oversee the quality-assurance data collection effort.


Candidate sites for monitoring were selected based on existing information and modeling needs. Those sites without adequate historical water quality data were then prioritized to arrive at proposed monitoring sites. Sites within the Coastal Plain were considered the highest priority. Integrator sites in subunits with no water quality data were given high priority, as were sites within any given subunit that could act as indicators of a particularly important land use. The nine highest-priority sites were selected for the proposed monitoring effort; of these, one new continuous surface water gaing station will be started, and one required restarting an inactive gage. Automatic samplers will be installed at seven sites to collect storm samples; regular baseflow and high-flow samples will also be collected. All samples will be collected using USGS sample-collection protocols. Nutrients will be analyzed at the USGS National Water Quality Laboratory (NWQL) in Denver; suspended-sediment analysis will be done at the USGS sediment laboratories in Iowa and Kentucky.

Gage construction began Summer 2000, and sample collection at all monitoring stations began October 2000. Installation of automatic samplers and rain gages was completed in Winter 2001, and each river station was fully operational and collecting streamflow, rain fall, and water quality data. The USGS web site also had real-time web access to each site at that time.


Historical data, data collected by MDE at numerous sites, and data collected for this study will provide information necessary for the development and calibration of an HSPF model of the Potomac River Basin, which in turn can be used as necessary input for a water quality model to be developed by MDE. The calibrated watershed and estuarine water quality model of the Potomac River Basin will allow resource managers to simulate large-scale effects of land-use changes and best management practices on water quality. The proposed study also meets several goals of the USGS Water Resources Division (WRD).

A second description of this project is available on the District homepage.

PROJECT CHIEF: Majedi, Brenda Feit
BEGIN DATE:    01 July 2000
END DATE:      31 December 2002