The Mohawk River: The backbone of the Hudson River under pressure
From pollution and invasive species to climate threats, how Riverkeeper is working to protect one of New York’s most vital waterways
March 25, 2026
Dan Shapley
Senior Director of Advocacy, Policy and Planning
Key takeaways
- The Mohawk River, the largest tributary of the Hudson, is critical to the tap water supply for over 250,000 people and is central to the region’s ecosystem and economy.
- Aging sewage systems, agricultural runoff, and climate change are driving water quality issues, including harmful algal blooms and high bacteria levels.
- The river’s connection to the Erie Canal has increased vulnerability to invasive species like zebra mussels and round goby fish.
- Riverkeeper is actively monitoring, advocating, and collaborating with state agencies to improve water quality, strengthen infrastructure, and prevent further ecological damage.
As the largest tributary of the Hudson River, the Mohawk River acts as a critical backbone for our region’s interconnected waters, and helps sustain the communities that depend on them. Through science, law, and advocacy, Riverkeeper works to protect and restore this vital waterway.
Where is the Mohawk River?
Named for the Mohawk people, one of tribes of the Haudenosaunee, the river starts in Oneida County in Central New York, and runs east nearly 150 miles before connecting with the Hudson River near Cohoes in New York’s Capital District.
What are the environmental and water quality issues on the Mohawk River?
Like the Hudson and many of its tributaries, the Mohawk River has rebounded dramatically since important state and federal environmental laws have been put in place. Leaks and overflows from aging wastewater infrastructure, and runoff from extensive farmland and roadways, however, contribute to water quality concerns, including excess nutrients, rising levels of road salt, and sewage-related pollutants.
This underlying pollution, along with the extreme temperatures and precipitation that are predicted to increase due to climate change, put the river at risk, including for harmful algal blooms that can be dangerous for wildlife and people’s health.
More than 250,000 people rely on the Mohawk for their tap water, with more than 100,000 in Colonie and Cohoes drawing from the river directly, and more than 150,000 in and around Schenectady relying on the Great Flats Aquifer, which is influenced by the river.
What is Riverkeeper doing to protect the Mohawk River?
As part of Riverkeeper’s boat program, Riverkeeper first patrolled the Mohawk River in 2014, keeping an eye out for polluters and any significant changes to the water and surrounding environment.
The Mohawk is part of Riverkeeper’s extensive water quality monitoring program, and we collect data along 120 miles of the river that helps better understand potential pollution and where and when the public can safely swim, boat, and play in the river.
In addition:
- We contribute data, insight, and knowledge to the annual Mohawk Watershed Symposium, an important event hosted by Union College that helps bring attention to issues and sets the agenda for research and management goals on the Mohawk River.
- Riverkeeper is adding our expertise to the current and upcoming New York State Department of Environmental Conservation’s (NYS DEC) 5-year Action Agenda, which sets goals for water quality improvements, habitat and fish protections, flood resilience, and access and public engagement in the Mohawk watershed.
- We are advocating for the NYS DEC to finish its “pollution diet” for nutrients entering the river. This plan would help build resilience to protect tap water sources, particularly as climate change brings heavier rainfall that causes nutrients from soil to run off into source water, affecting water quality. Reducing ways nutrients enter the Mohawk will also reduce nutrients that flow into the Hudson.
- Riverkeeper has completed a monitoring plan to check several tributaries of the Mohawk River for sewage bacteria. Through this program, our team of collaborators at SUNY Cobbleskill and Union College sampled at more than two dozen stream locations. Future monitoring plans are in development by the Mohawk Affinity Group, as part of Riverkeeper’s Hudson River Water Quality Monitoring Collaborative.
- We prompted the U.S. Environmental Protection Agency to organize a “spill drill" to improve emergency response capabilities in case of a spill into the river from the hazardous cargo transported along the nearby railroad. The tracks hug the river for many miles, and our advocacy helped ensure that impacts to the river ecosystem and tap water were considered as priorities with this drill.
- In addition to a range of policies that have positive impacts on all New York State waters, Riverkeeper advocates for state and federal laws and regulations to support continued improvements in the Mohawk River, including the state Mohawk Basin Management Act and the federal NY NJ Watershed Protection Act. The federal government has authorized up to $100 million to support infrastructure improvements, thanks to Riverkeeper’s advocacy.
How are invasive species impacting the Mohawk River?
The Erie Canal was built to take advantage of the unique east-west geography of the Mohawk Valley. The canal transformed the free-flowing Mohawk into a uniquely highly engineered river, with locks, dams and hydroelectric power facilities altering its flow. The canal brought historic changes to New York life and commerce, and it also facilitated widespread industrial pollution that was common during the region’s industrial heyday. By connecting the Mohawk unnaturally to the west at the point that the Oneida people called “the great carrying place” the canal has also exposed the Mohawk and Hudson to invasive species from the Great Lakes, such as zebra mussels and the round goby.
Aquatic invasive species threaten the ecology of the Hudson River and its tributaries by taking the place of, competing with, or preying on native species. Studies of the Mohawk River often find more non-native fish species than native.
Riverkeeper is currently working with the NYS DEC, the New York State Canal Corporation (the state authority that oversees the Erie Canal), and scientific partners to address the issue of invasive species. We are pushing for an engineered solution at Rome, NY that still allows boats to use the canal but prevents invasive species from passing through.
About Dan
Dan Shapley leads Riverkeeper’s advocacy and policy efforts to protect the Hudson River and its tributaries, including the Mohawk. With experience in environmental research, public communication, and advocacy, he works to translate complex water data into actionable solutions, helping safeguard tap water, restore ecosystems, and hold polluters accountable across New York State.
Related campaigns
Spill prevention and preparedness
Working to protect the Hudson and its communities from the threats posed by anchor strikes and spills
Sewer and stormwater pollution
Working to keep sewage and street pollution out of our waterways
Emerging and unregulated contaminants
Toxic chemicals can harm the health of people, wildlife, aquatic ecosystems
Remediating and preventing contamination
Cleaning up decades of pollution and preventing more requires scientific understanding, targeted legal action, and sustained advocacy
Invasive species
Protecting the Hudson includes defending it against outside threats
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