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What is a Watershed?

how watersheds work

 (photo used with permission from Michigan Sea Grant)

A watershed is an area where all of the water empties to a particular body of water. You can see in the photo above that water will run-off or "shed" from the surface and roll downhill through forests, farms, sub-divisions, and city streets picking up potential contaminants along the way to the river and lake. Watersheds can be large or small. The Great Lakes Watershed is very large, also called the Great Lakes Basin, and drains water from eight states and one Canadian province (see photo below). The area highlighted in yellow drains to Lake Erie and represents the Lake Erie Watershed.

great lakes

The Niagara River/Lake Erie Watershed includes the land area within New York State that drains to these waterbodies. A watershed management plan is currently under development for this area to asses the threats and develop potential projects to protect and improve water quality in all of the waterbodies that drain to Lake Erie and the Niagara River.

Niagara River/ Lake Erie Watershed map

An example of a smaller watershed is the Tonawanda Creek watershed, as shown in green on the map below. The Tonawanda Creek Watershed Committee is a group of concerned citizens and stakeholders working together to protect the area of land that drains to Tonawanda Creek. This watershed has many of the same issues and features as a watershed that is larger in size. For instance, did you know that:

  • The aquatic invasive species, hydrilla, has been found in Tonawanda Creek and can be transported to other waterways by watercraft or waterfowl;
  • Erosion of stream banks has caused roads and homes to slide into the creek;
  • Log jams and debris build-up sometimes cause flooding, especially in the flat areas;
  • There are many fishing and canoeing/kayaking opportunities in the streams that flow in the watershed;
  • Several beautiful waterfalls exist as an example of the geology of the region;
  • Tonawanda Creek is a source of drinking water for Batavia;
  • There are both agricultural/rural areas as well as suburban/urban areas in the watershed, and;
  • Swamps in the area offer excellent wildlife viewing.

Tonawanda Creek

Tonawanda Creek is one of the largest sub-watershed areas in the Niagara River/Lake Erie Watershed of Western New York. It is comprised of 405,606 acres or 648 square miles, and is approximately 101 miles long. The drainage basin of Tonawanda Creek includes portions of Wyoming, Genesee, Orleans, Niagara, and Erie Counties, as well as the Tonawanda Seneca Nation.

Its headwaters start in the Town of Wethersfield, Wyoming County where the elevation is more than 1,800 feet. The Creek flows northward from Wyoming County to Batavia where it turns west and continues its flow along the boundary of Erie and Niagara Counties until it reaches the Niagara River in the cities of Tonawanda and North Tonawanda. The Barge Canal is also a part of Tonawanda Creek from approximately Hopkins Road in Amherst to the Niagara River.  Cultivated land represents 45% of the land use in the watershed while, forests comprise 27% and wetlands 11%.

You can find out more about local watersheds in the Regional Niagara River/Lake Erie Watershed Management Plan.