What are watersheds?
A watershed is an area of land that drains all the stream and rainfall to a common outlet such as the outflow of a reservoir, mouth of a bay or any point along a stream channel.[1]
Watersheds can consist of surface water like lakes, streams, reservoirs and wetlands, and all the underlying groundwater.
Watersheds can vary in size from a small puddle of water to a body of water that is large enough to encompass the land that drains water into rivers and larger water bodies.
The water is initially collected from rainfall, snowmelt and runoff.
You can think of a watershed as a bowl that collects all the water in a certain area and concentrates the water to waterbodies like rivers, lakes and groundwater.[2]
Are watersheds good or bad?
Water is a finite resource. Anything that naturally collects water, filters it and concentrates it to a specific area can be considered a good thing.
Without watersheds collecting water into streams and waterbodies we’d be left searching for miniscule amounts of water.
Watersheds are a naturally occurring collection tool for water. They act like a giant funnel that collects water into a waterbody.
According to the New Hampshire Department of Environmental Services (DES), watersheds are “extremely important.”[3]
DES states that healthy forested watersheds provide services like cleaning our drinking water supplies and stabilizing soil.
The waterbodies that watersheds drain to also provide us with recreational opportunities and aesthetic benefits—they’re beautiful!
What are the major watersheds in North America?
There are six generally recognized hydrological continental divides which divide the continent into seven principal drainage basins spanning three oceans.
The basins include:
- Atlantic Seaboard basin
- Gulf of Mexico basin
- Great Lakes-St. Lawrence basin
- Pacific basin
- Arctic basin
- Hudson Bay basin
- Great basin
What is the most famous watershed?
The largest watershed in the U.S. is the Mississippi River Watershed, which drains about 1.15 million square miles from all or parts of 31 U.S. state and two Canadian provinces stretching from the Rockies to the Appalachians.[4]
What definition best describes a watershed?
A water shed can best be described as an area of land that drains all the streams and rainfall into a common outlet. These outlets can include things like the outflow of a reservoir, mouth of a bay, or any point along a stream channel.[5]
A watershed can also be thought of as a precipitation collector. When it rains, a watershed acts like a giant collection bowl.
Not all water is retained in the watershed. Precipitation can be retained by the watershed instead of flowing into local water bodies.
Things like infiltration, evaporation, transpiration and storage allow water to be retained by the watershed.
What is the purpose of a watershed?
A watershed is an area of land where water from rain or snow melt drains downhill into a body of water like a river, lake, wetland or ocean. Watersheds include both streams and rivers that convey the water as well as the land surface from which the water drains into those channels.[6]
Watersheds can be used to determine where runoff from precipitation collects. Municipalities and state governments can study watersheds and utilize them for natural water collection.
Sources
[1] https://www.usgs.gov/centers/california-water-science-center/science/science-topics/watersheds#:~:text=A%20watershed%20is%20an%20area,point%20along%20a%20stream%20channel.
[2] https://www.fisheries.noaa.gov/new-england-mid-atlantic/habitat-conservation/what-watershed
[3] https://www.des.nh.gov/sites/g/files/ehbemt341/files/documents/2020-01/wmb-19.pdf
[4] https://oceanservice.noaa.gov/facts/watershed.html#:~:text=The%20largest%20watershed%20in%20the,the%20Rockies%20to%20the%20Appalachians!
[5] https://www.usgs.gov/special-topics/water-science-school/science/watersheds-and-drainage-basins#overview
[6] https://cteco.uconn.edu/guides/Basin.htm#:~:text=A%20drainage%20basin%20is%20an,water%20drains%20into%20those%20channels.
