What’s a watershed anyway?
Watersheds come in many shapes and sizes. That’s because Mother Nature doesn’t recognize city, county, state or national boundaries. It’s the geography and the contours of the land that determine where the water drains.
And that’s the key to understanding the concept of a watershed. A watershed is an area of land where all of the water that is above ground and even below ground drains into the same place.
The United States Environmental Protection Agency (EPA) offers this quote from scientist and geographer John Wesley Powell to better explain the idea of a watershed:
"That area of land, a bounded hydrologic system, within which all living things are inextricably linked by their common water course and where, as humans settled, simple logic demanded that they become part of a community."
That explains why there are a lot of watersheds in the United States. There are 2,110 watersheds in the continental U.S. If you include Hawaii, Alaska, and Puerto Rico, the number jumps to 2,267 watersheds.
But you need to go back to Powell’s definition to understand why the concept of watershed is so important. It’s because we all live in a watershed, and a healthy watershed is vital to a healthy environment and economy. Everyone needs water and other natural resources to live and most of those natural resources depend on water in some way. It’s important that everyone realizes what we do on the land impacts the quality of the water that we and every other living thing depend on.
Call it a bigger understanding of what a watershed is.
And that larger view has led to huge changes in urban planning and land use. Scientists, political leaders and urban planners now realize that the best way to protect natural resources is to manage them on a watershed basis.
Think about pollution.
In the past, pollution was dealt with on a case-by-case basis. You simply went to the source of the pollution. If you control the leak at the pipe, for example, the pollution problem was solved. But the more people understood the concept of a watershed, the more people realized that water quality issues don’t just arise from one leaking pipe. Fertilizer runoff from farmlands or front yards, oil and gasoline runoff from parking lots, even aging septic systems all contribute to pollution and to a degraded watershed.
The broader understanding of watersheds is leading to a broader understanding of how to take care of them.
- Frank Graff
Frank Graff is a producer/reporter with UNC-TV, focusing on North Carolina Science Now, a weekly science series that airs Wednesdays, beginning in August 2013, as part of North Carolina Now on UNC-TV. In addition to producing these special segments, Frank will provide additional information related to his stories through this North Carolina Science Now Reporter's Blog!
What’s a watershed anyway?