The Chesapeake Bay Program nontidal water quality monitoring program began in 2004 to better estimate nutrient and sediment loadings from Chesapeake Bay watersheds. The nontidal monitoring program consists of 126 stations throughout the region and includes 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 water quality loads and trends for nutrients and sediments delivered downstream. Routine samples are collected monthly with eight additional storm-event samples per year to obtain a range of discharge and loading conditions.
The Chesapeake Bay Program Nontidal Water Quality Workgroup coordinates the design and implementation of the monitoring program to ensure comparability among participants. Sampling is performed by 10 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 USGS training video demonstrates some of the field procedures.
Non-tidal data are reported to the Chesapeake Bay Program and available on the CIMS network. The accuracy and comparability of the nutrient data are independently evaluated through the inter-laboratory Chesapeake Bay Split Sample and Blind Audit Programs and the USGS Standard Reference Sample Program.