Department of Environmental Conservation

D E C banner

Chesapeake Bay Watershed Program

The Chesapeake Bay is the largest estuary in the United States. It is home to more than 2,700 species of plants and animals and produces about 500 million pounds of seafood per year. The Bay's watershed covers portions of six states and Washington, D.C.

Watershed facts:

  • Area: 64,000 square miles including portions of 6 states (Delaware, Maryland, New York, Pennsylvania, Virginia, and West Virginia) and Washington, D.C.
  • New York area: 6,250 square miles in 19 counties
  • Population: More than 17 million people live in the watershed
  • New York population: About 640,000 people live in New York's portion of the Bay watershed
  • Source: The Susquehanna and Chemung rivers in New York form the northern headwaters of the Bay

New York's Connection to the Chesapeake Bay

New York's portion of the Chesapeake Bay watershed is made up of the Susquehanna River watershed and Chemung River watershed. Together these two watersheds form the northern headwaters of the Chesapeake Bay and cover much of New York's Southern Tier.

The Susquehanna River begins at Otsego Lake in Cooperstown, New York and flows 444 miles south to the northern end of the Chesapeake Bay in Maryland. The Chemung River flows across the western portion of the Southern Tier and joins the Susquehanna River in northern Pennsylvania. The Susquehanna River is the Bay's largest tributary. It provides nearly 50 percent of the fresh water that enters the Bay - an average of 19 million gallons of water per minute.

In total, some or all of 19 New York counties are in the Chesapeake Bay watershed: Allegany, Broome, Chemung, Chenango, Cortland, Delaware, Herkimer, Livingston, Madison, Oneida, Onondaga, Ontario, Otsego, Schoharie, Schuyler, Steuben, Tioga, Tompkins, and Yates.

Water Quality Problems and Solutions

Excess nutrients (nitrogen and phosphorus) and sediment from all over the Chesapeake Bay watershed degrade the Bay's water quality. The main nutrient sources are sewage, cattle manure, inorganic fertilizer and atmospheric nitrogen deposition. Most of the sediment comes from agriculture, stream bank erosion and construction.

The Chesapeake Bay Total Maximum Daily Load

The U.S. Environmental Protection Agency established the Chesapeake Bay Total Maximum Daily Load (TMDL) in December 2010 to address the water quality problems in the Chesapeake Bay caused by excess nutrients and sediment.

A Total Maximum Daily Load defines the capacity of a waterbody to absorb a pollutant and still meet water quality standards. The Chesapeake Bay TMDL sets limits on the amount of nutrients and sediment that can enter the Bay and allow it to meet water quality goals. Because nutrients and sediment in the Bay come from all over the watershed, all six states and Washington, D.C. are involved in the work to meet the goals outlined in the TMDL.

A Plan to Improve Water Quality

All six states (and Washington, D.C.) in the Chesapeake Bay watershed developed, and are now implementing, Watershed Implementation Plans (WIP) that describe the contributions each state will make toward improving water quality in the Chesapeake Bay. Each state also develops two-year goals, called milestones, that outline short-term steps toward the long-term objectives described in the WIPs. Quality assurance and verification procedures provide confidence in the data reported to EPA each year.

Phase III Watershed Implementation Plan

DEC has completed the last phase (Phase III) of New York's Watershed Implementation Plan (WIP). DEC worked with the New York State Department of Agriculture & Markets, the Upper Susquehanna Coalition (the USC represents 17 New York and 4 Pennsylvania counties in the Chesapeake Bay watershed) and Cornell University to develop New York's Phase I, Phase II , and Phase III Watershed Implementation Plans.

Main Document: May 2021 Final Phase III Watershed Implementation Plan Amendment for New York's Chemung and Susquehanna River Basins (PDF)


As part of EPA's evaluation of the Amended Phase III WIP, DEC worked with EPA to develop an agreed-upon methodology to assess growth in all sectors and establish a growth tracking threshold, which if triggered, will require additional actions to be implemented to offset growth in loads. The 2022-2023 milestones will include the a growth tracking milestone for each sector, including the results of the Chesapeake Bay Significant Wastewater Treatment Plant Growth Methodology (PDF) analysis. Below is the May 2021 Final Amended Phase III WIP and appendices, EPA's evaluation of the November 2020 Final Amended Phase III WIP, and DEC's response to that evaluation.

Past Watershed Implementation Plans
Two-Year Milestones

DEC works with the Department of Agriculture and Markets, the Upper Susquehanna Coalition and other partners to develop and implement New York's two-year milestones. Each set of milestones includes program actions in addition to implementation of specific best management practices. The current milestone period runs from January, 1 2022, through December 31, 2023.

Past Two-Year Milestones
Quality Assurance and Verification

The following quality assurance project plans for point and nonpoint sources of nutrients and sediment describe the procedures New York follows to collect, report and verify BMP information in the Chesapeake Bay watershed.

The Chesapeake Bay Program produced a Quick Reference Guide for Best Management Practices (PDF) that provides summarized profiles for each Chesapeake Bay Program approved BMP in the Watershed Model.

Chesapeake Bay Riparian Buffer Action Strategy for New York

DEC worked with the Upper Susquehanna Coalition to develop the Chesapeake Bay Riparian Buffer Action Strategy (PDF)for the Upper Susquehanna and Chemung watersheds. The strategy includes current opportunities for implementation, technical assistance, and support needed to meet the riparian buffer targets included in the Watershed Implementation Plan.

Upper Susquehanna Watershed Progress Dashboard

screenshot of ARC GIS map

The purpose of this ArcGIS Dashboard (leaves DEC website) is to provide stakeholders with a simple and direct platform to access data and information relevant to the Upper Susquehanna Basin and Chesapeake Bay TMDL in New York. Users can view current BMP implementation, water quality trends, locations of recent state biological monitoring results, and estimated nutrient and sediment loads delivered to the Chesapeake Bay. The Upper Susquehanna Watershed Progress Dashboard Guide (PDF) contains step-by-step directions on how to use the dashboard.