Explore the Lake Champlain Basin

Your environment – the land, river, streams and lakes – all work together to process, filter and otherwise manage rainwater.

Over time, these areas can be polluted, erode, or otherwise fill with sediment or other materials, causing both short and long-term problems in the environment.

What is a Watershed?

Learn about what makes up a watershed and how stormwater runoff affects the stream, rivers, and Lake Champlain.

A watershed is an area of land that drains all the streams and rainfall to a common outlet such as the outflow of a reservoir, mouth of a bay, or in this case, Lake Champlain. The word watershed is sometimes used interchangeably with drainage basin or catchment.

The watershed consists of surface water–lakes, streams, reservoirs, and wetlands–and all the underlying ground water.

 Larger watersheds contain many smaller watersheds. It all depends on the outflow point; all of the land that drains water to the outflow point is the watershed for that outflow location.

There are actually 11 different sub-basin or smaller watersheds, that feed into the Lake Champlain watershed. Some of the smaller watersheds are on the New York side of Lake Champlain, some are on the Vermont side, and some extend into Canada.

Watersheds are often separated by hills, mountains, or other geographic features.

Rain and snow melt is commonly referred to as stormwater. Any stormwater not absorbed by the ground flows into the stream and rivers, carrying with it pollutants and dirt it picks up along the water. As it travels through the streams and rivers, some of the pollutants and dirt remains in the streams and rivers.

Over time, the streams and rivers carry stormwater to Lake Champlain.  The stormwater carried into Lake Champlain brings with it the pollutants and dirt.

Water that is absorbed by the ground is often filtered before it reached groundwater deposits. This groundwater also feeds into the lake underground via percolation.

By decreasing the amount of stormwater that flows directly into streams and rivers, you can help reduce the pollutants and dirt in streams, rivers, and Lake Champlain.

Explore our Watershed

Click the checkboxes below and take a look at the watershed you live in, as well as impaired rivers and streams around your neighborhood.

Stream Monitoring

Stream monitoring is an important component of stormwater mitigation. Each year, volunteers are needed to take water samples from various local streams. These samples are sent to a lab and analyzed.

Where do we monitor?

The data collected through stream monitoring helps to guide our project selection process. Volunteers are recruited in the late spring and trained before testing begins in early summer. We currently monitor Chloride, Phosphorus and Turbidity in the following streams:

What do we monitor?

Sodium Chloride

Chloride is a component of salt found naturally in minerals and in oceans. Elevated chloride levels in surface waters can lead to poor health and reduced reproduction in aquatic species, according to the Vermont Surface Water Management Strategy. The sources of chloride in water include road deicing salts, wastewater form industries and municipalities, and leachate from landfills.


Phosphorus is an essential nutrient for plants and animals in the aquatic food web and is naturally limited in most fresh waters; therefore, even a modest increase can set off a chain of undesirable events. Such events include algal blooms, accelerated plant growth, low dissolved oxygen, and death of aquatic animals. Phosphorus naturally occurs in soils and rocks. Additional phosphorus enters waterways through runoff from wastewater treatment plants fertilized lawns and cropland, failing septic systems, animal manure storage areas, pet waste and from erosion.


The turbidity of a water sample refers to its cloudiness. This measurement is based on the amount of algae, microbes, and sediment suspended in the water. Turbidity measurements can be used as an indicator for erosion and/or nutrient concentration. Higher turbidity levels can indicate a higher chance of disease-causing organisms being present.

Why do we monitor?

Consistent data related to water quality and quantity allows stormwater managers to better assess the state of our waters and develop solutions that will have a lasting positive effect.  Volunteers are typically used to collect samples at a variety of locations along a stream or within a watershed. On occasion, volunteers may also gather visual data as to the condition of a stream. Data collected in this way may include presence or absence of riparian buffers, streambank stability, and presence of litter or trash.