The Chesapeake Bay Program nontidal water quality monitoring program began in 2004 to better estimate nutrient and sediment loadings from the region’s rivers and streams.

The nontidal monitoring network consists of 126 stations throughout the Chesapeake Bay watershed and includes the nine River Input Monitoring stations, representing about 2/3 of the flow above the fall line. Stations are located near USGS stream-flow gages to permit estimates of nutrient and sediment loadings and trends in loadings delivered downstream. Routine samples are collected monthly, and eight additional storm-event samples are collected per year to obtain 20 samples per year, representing a range of discharge and loading conditions.

The Chesapeake Bay Program Integrated Monitoring Networks Workgroup provides inter-agency coordination among the nontidal network participants to ensure the continuity of operations. Sampling is performed by nine agencies in five states, with five laboratories analyzing the samples. Participants follow standard operating procedures that conform to Nontidal Network protocols and quality control specifications, which are based on USGS sampling methods and EPA-approved analytical methods.

The Bay Program Data Integrity Workgroup routinely evaluates laboratory performance through inter-laboratory studies such as the Chesapeake Bay Split Sample and Blind Audit Programs and the USGS Standard Reference Sample Program. Nontidal water quality data are reported to the Bay Program and are available in the Data Hub.

Quality Assurance Project Plans

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