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Charles County, Maryland

What is a Watershed?

What is a Watershed?

A watershed is the land area that drains to a stream, lake, river, bay or ocean.  In each watershed all of the water that falls in it, and drains off of it, goes to a common outlet, such as a reservoir outflow, mouth of a bay, or any point along a stream channel.  We all live in a watershed, and the condition of our watershed is important to everyone and everything that uses and needs water.   

Watersheds include surface water, like lakes, streams, reservoirs, and wetlands, and underlying groundwater. Water that flows over or through a watershed eventually ends up in the waterway to which it drains, including what is picked up along the way.  Development projects, stormwater runoff patterns, the location of pollution sources, and groundwater and stream flow all affect the health of our watersheds.    

Watersheds can be large or small, and smaller watersheds can make up a much larger one.  Charles County is located in the Chesapeake Bay watershed, which spans 64,000 square miles across the District of Columbia and parts of six states – Maryland, Virginia, Pennsylvania, Delaware, West Virginia, and New York.  This means all the water that comes through or originates from Charles County drains to the Chesapeake Bay. 

Maryland has 138 smaller watersheds, called 8-digit scale watersheds, representing drainage divides between 3rd order rivers or streams.  There are ten 8-digit scale watersheds within Charles County – Mattawoman Creek, Patuxent River Lower, Nanjemoy Creek, Gilbert Swamp, Zekiah Swamp, Wicomico River, Port Tobacco River, Potomac River Lower Tidal, Potomac River Middle Tidal, and Potomac River Upper Tidal.

Explore the 8-digit watershed you live in by visiting the Maryland Department of Environment’s (MDE)’s map of Maryland watersheds.

Explore Your Watershed