Annual Water Quality Reports

Friends of the Bay’s Water Quality Monitoring Program is an important component of our efforts to protect the Oyster Bay/Cold Spring Harbor estuary and surrounding watershed. It serves to increase public awareness of local threats to water quality. This program was developed in cooperation with the United States Fish and Wildlife Service, United States Environmental Protection Agency, New York State Department of Environmental Conservation, local governments and other citizen monitoring groups around Long Island Sound.

Friends of the Bay monitors 8 locations within Cold Spring Harbor, Oyster Bay Harbor and Mill Neck Creek. Each site is monitored once per week May through October, weather and tide permitting, for dissolved oxygen, bacteria, salinity, temperature, pH and clarity. Nitrogen samples are collected once per month for analysis.

This program initiated in the late 1990s to continue data collection efforts that were canceled due to county funding cuts. Friends of the Bay considers this program a necessary component of the effort to preserve, protect and restore the Oyster Bay/Cold Spring Harbor complex. In 2006 and recently in 2020, Friends of the Bay received a Quality Assurance Project Plan from the Environmental Protection Agency. This program enables trained citizen scientists working alongside Friends of the Bay staff to monitor the marine ecosystem. In 2009, the program was given a Region 2 Environmental Quality Award by the Environmental Protection Agency.

Water quality reports are prepared by Fuss & O’Neill using the data collected by Friends of the Bay. Raw data is posted in the water quality data section under the monitoring tab on this site.

2022 Water Quality Monitoring Report

Click here to download a pdf of the report

We have been monitoring water quality in the estuary since 1999 via our core monitoring program, adding Save the Sound's Unified Water Study program in 2017, with a small staff and a fantastic crew of volunteers.

A report of our 2022 data was prepared by Fuss & O'Neill, a civil engineering and environmental consulting firm which FOB has been working with for decades.

The good news is that in Cold Spring Harbor, Oyster Bay and Mill Neck Creek, the seasonal trend for fecal coliform has generally been decreasing since 2000 – around the time we started sampling. This trend has been improving since sewage from failing septic systems in the Birches housing development in Locust Valley was redirected to the treatment plant in Glen Cove. Compared to 2011, the 2022 average fecal bacteria levels in Mill Neck Creek were, again, down substantially - fecal coliform was down 60% and enterococci down 76%.

In 2022 the swimming standards for fecal coliform and enterococci were not exceeded at any sampling site. The highest levels were generally detected after significant rain, demonstrating that stormwater may be a significant contributor to bacteria loads.

Among the issues we are monitoring are a problematic outfall in Cold Spring Harbor, declining oyster populations and overall health of the bay. As recommended by Fuss & O'Neill, we plan to revive testing for nitrogen as well as stream and outfall samplings. We are seeking funding for both initiatives.