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305(b) Groundwater Quality Basin Reports

Ambient Groundwater Monitoring Program

As an ongoing cooperative project between the NYSDEC Division of Water and the USGS, this program supports NYSDEC's federally designated responsibility to assess and report on the quality of New York's ground water as part of the requirements of the 305(b) section of the Clean Water Act Amendments of 1977. The objectives of the Ambient Groundwater Monitoring Program are: to assess and report on the quality of the state's groundwater; identify long-term groundwater quality trends; characterize naturally occurring or background conditions; and establish an initial statewide comprehensive groundwater quality baseline for future comparison. The program is designed so that all major drainage basins in the state are monitored once every five years.

305(b) Major Basins
305(b) Major Basins


The program started with a pilot study of the Mohawk River basin in 2002. This was followed up with a partial study of the Chemung River basin (2003) and full studies of Lake Champlain and Upper Susquehanna River basins (2004); St. Lawrence, Delaware and Genesee River basins (2005); and Alleghany, Lake Erie / Western Lake Ontario and Mohawk / Schoharie basins (2006). Studies of the Upper Hudson and Chemung River basins (2007); and Lower Hudson and Black River basins (2008) will complete the first full rotation of studies.

Study Basics

Each study-year a total of 60 wells are anticipated to be sampled. This number is then divided among the basins being studied. The final selection of wells attempts to achieve an equal split of public & private wells, an equal split of bedrock & overburden aquifer wells, and also an overall equal geographic distribution of wells. The majority of private wells considered for sampling are obtained from the DEC Water Well Program.

DEC and USGS plan the study cooperatively. USGS personnel conduct each study with oversight by DEC.

DEC's Pesticide Reporting Program provides funding in part to fulfill state pesticide monitoring requirements.

Sampling and analysis of groundwater includes field and physical parameters, bacteria, nutrients, inorganics, organics (including pesticides and VOCs), and radiochemicals.

Reports and Data

Data reports are developed by the USGS for each major basin and are available online at USGS's New York 305(b) Ambient Groundwater Quality Monitoring webpage (leaves NYSDEC website) approximately one year after completion of respective studies. Resulting raw data is also available from the USGS through their National Water Information System (NWIS) website.

More Information

For more information on other DEC ongoing water quality monitoring efforts, please see our page on the Routine Statewide Monitoring Program.