Water Quality

Flyfishing on a riverWe know that climate change is altering rain and snowfall patterns in Vermont, but we are just beginning to understand the complex interactions among these changes and our land use habits. Protecting our waters from climate change means protecting the natural processes that keep them healthy.

More water is running through our streams and rivers, arriving faster and warmer than it used to. Development and loss of wetlands is preventing water from seeping into the ground while land clearing along shorelines is reducing tree cover that keeps water cool. Giving our streams and rivers space to move will reduce erosion rates, create  and allow for natural deposition that rebuilds nutrient-rich floodplains.

More frequent algal blooms

Cyanobateria bloom in August of 2015
Cyanobacteria bloom in August 2015
Cyanobacteria (formerly called blue-green algae) blooms in Lake Champlain have gained public attention because of both their appearance and their toxicity. State government, watershed groups and lake associations have stepped up efforts to curb phosphorus pollution through education, outreach, and policy change.

Phosphorus and nitrogen are essential building blocks of life on Earth. In undisturbed environments, most phosphorus and nitrogen is snapped up by living organisms or held in the soil. They make plants grow quickly and are common ingredients in fertilizers.

When erosion carries soil and fertilizers into surface waters, the phosphorus and nitrogen become available to aquatic plants, algae, and bacteria. Lakes act as sinks for these nutrients, balancing input from stormwater with storage in plants, fish and other aquatic life. Too much phosphorus and nitrogen, especially when it arrives too quickly, changes the balance.

Multiple stressors

Long-term phosphorus concentrations continue to rise in portions of Lake Champlain. But like all factors contributing to our rapidly changing ecosystems, phosphorus does not act alone. The repercussions of too much phosphorus are exacerbated by its interaction with other ecosystem factors including surface water temperature, seasonal water flow and the presence of invasive plants and animals. Climate change affects all of these -- our mitigation efforts must as well.

Mid-season 2015 cyanobacteria tracking resultsIs it safe to swim?

Vermonters love to swim in local lakes and ponds. But high levels of bacteria and bacterial toxins can cause public beach closures and make residents wary of swimming where water is not tested.

Heavy rainstorms cause some municipal sewers to overflow, resulting in coliform bacteria overloads (most commonly E. coli) that can make people sick. Although cyanobacteria blooms have yet to cause serious health effects for people using Lake Champlain, they can cause skin irritation, digestive problems, and even damage to the liver or central nervous system if ingested. Check on the status of cyanobacteria blooms where you like to swim this summer using the Vermont Department of Health Cyanobacteria Tracker.

Water of life

Approximately 145,000 people surrounding Lake Champlain source their drinking water from the lake. Most of these public water suppliers are monitored by state and provincial governments and are tested for cyanobacteria toxins during the summer.

The Vermont Department of Health advises against drinking untreated surface water that may contain not only cyanobacteria toxins but also bacteria, viruses, parasites, and other contaminants. Suface water should be treated before drinking and private wells and springs should be regularly tested to ensure they are safe.  Visit the Department of Health's Safe Water Resource Guide for more information on water quality testing .

Learn More

The Vermont Agency of Natural Resources is addressing water quality concerns in the state through field monitoring, research, and collaboration with schools and universities. Contact the Watershed Management Division to find out more.

For more information on how climate change is affecting water quality in Vermont, visit:

Climate Change and Vermont’s Waters from the ANR Climate Change Adaptation White Paper Series

How is climate change affecting Lake Champlain? - Lake Champlain Basin Program

Vermont ANR Climate Change Adaptation Framework (2013) - Vermont Agency of Natural Resources

Vermont Surface Water Management Strategy - ANR Department of Environmental Conservation

Flood Ready Vermont - Agency of Natural Resources

EPA Climate Change Website

Union of Concerned Scientists on Global Warming

New guidelines outlined in the 2015 Vermont Lake Champlain Phosphorous TMDL Phase 1 Implementation Plan are more comprehensive than those set in 2002, accounting for both historic land use patterns and predicted climate change patterns in the region. A link to the final report will be available soon.



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