Watersheds

A watershed is any area of land that drains into a common water body such as a stream, river, lake, or wetland. Each watershed is separated from other watersheds by high points in the terrain, such as hills and ridges. A watershed includes not only the water body or waterway itself, but also the entire land area that drains into it. A watershed may be very small, like the drainage formed by your own driveway, or very large, like the drainage basin of the Delaware or Mississippi Rivers. Depending on the size of a watershed, it may be referred to as a drainage basin, watershed, sub-watershed, or catchment.

New Jersey’s rivers and streams flow either to the Atlantic Ocean or to the Delaware River and Bay. They are thus in either the Atlantic drainage or the Delaware River watershed. In Gloucester County, all except one of the streams and rivers flow to the Delaware.

The Delaware River Watershed is 13,000 square miles in size and covers parts of four states (New York, New Jersey, Pennsylvania, and Delaware). Although the watershed occupies only 1 percent of the land of the United States, it supplies water to 10 percent of the U.S. population. Many small municipalities and large metropolitan centers get all or part of their drinking water from the river, including Philadelphia, Trenton, and New York City, which obtains its water from reservoirs located in the headwaters of the Delaware.

All land–including our neighborhoods, commercial and industrial areas, forests, and parkland–is in one watershed or another. Each watershed is a dynamic and unique place, where our natural resources, such as soil, water, air, plants, and animals, interact in a complex web. Yet, everyday activities can impact these resources, ultimately affecting our own health, well-being, and economic livelihood.

In New Jersey, the Department of Environmental Protection monitors and manages our natural resources on a watershed basis. The state has been divided into 20 Watershed Management Areas (WMAs). The watersheds in Gloucester County are part of three Watershed Management Areas:

• WMA 15 – Great Egg Harbor, Tuckahoe
• WMA 17 – Maurice, Salem, and Cohansey
• WMA 18 – Lower Delaware Tributaries

Definitions
 
Drainage basin: A large watershed encompassing the watersheds of many smaller rivers and streams and draining to a major river, estuary, or lake.
 
Watershed: The land area from which surface runoff drains into a particular stream channel, lake, river, or other body of water.
 
Sub-watershed: The land area draining to the point where two smaller streams combine together to form a larger, single stream.
 
Catchment: The smallest watershed area, usually defined as the area that drains an individual site, such as a school or small neighborhood, to its first intersection with a stream.

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