How Can We Protect Watersheds?

How can we protect watersheds?

By: Cathy Carr

One major source of pollution in water is sediment. Sediment comes from erosion which is the wearing away of exposed soil over time due to water, ice and wind. Some examples of areas that can contribute to sediment in streams are:

construction sites
roads (construction of and unpaved)
timber harvesting
agricultural/crop fields

Which of these erosion sources has the highest erosion rate? Here are some numbers to illustrate the amount of erosion each creates:

Steep, poorly constructed forest roads - 100 tons/acre/year
Construction site – 100-200 tons/acre/year
Cropland – 6.18 tons/acre/year
Pasture – 3.51 tons/acre/year
Undisturbed forest – 0.82 tons/acre/year
Recently harvested Clearcut – 4.66 tons/acre/year

So what can be done to help prevent erosion in the forest setting?

The Virginia Department of Forestry produces a manual called Best Management Practices for Water Quality. This manual sets out guidelines for foresters, loggers or anyone else in the woods on how to minimize impacts to the streams. This BMP manual has sections regarding roads, skid trails, decks, and stream crossing to mention a few.

Some common BMP’s for harvesting sites include:

streamside management zones
reseeding skid trails and decks after finishing
placing water bars on the skid trails
if the road leading into the area is not being used any more close it out

Some common BMP’s for roads include:

putting a gate up
putting gravel down on the road
daylighting the road (removing trees that may keep the road shaded)
locating new roads on gentle terrain and stable soils
To see a classroom demonstration of erosion, click here.

These are just a few of the BMP’s listed in the manual. If you are interested in a manual contact the Virginia Department of Forestry.

Questions:

What is a major source of pollution in water?
What is the erosion rate for pasture compared to the erosion rate of a construction site?
Where can guidelines for minimizing impacts to streams be found?

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