Vegetative buffers

Cleaning and Protecting Wisconsin’s Waters

Vegetative Buffers: The most effective protection for our water resources

12/11/01

The Problem

- how you can help

Polluted runoff—which occurs when rainfall, snowmelt, or irrigation washes pollutants such as sediment, nutrients, and pesticides into lakes, streams, coastal waters, and ground water—is the number one source of pollution to the waters of our state.

According to the DNR, polluted runoff degrades or threatens an estimated 40 percent of the streams, 90 percent of the inland lakes, many of the Great Lakes harbors and coastal waters, many wetland areas and substantial groundwater resources in Wisconsin.

Vegetative Buffers

Studies show that vegetative buffer zones are highly effective for controlling sedimentation, erosion, and pollution from runoff. Sedimentation occurs when excess soil particles accumulate in water bodies, which can suffocate organisms and reduce sunlight needed by aquatic life. Pollutants that are attached to soil particles are transported by sediment to the water.

Two common pollutants, phosphorus and nitrogen, cause excessive algae growth, deteriorate water quality, and can kill fish. Phosphorus and nitrogen are the basic nutrient elements of fertilizer.

Buffers trap sediment and allow phosphorus and nitrogen to filter into the soil, thereby preventing it from getting into the streams and lakes.

Buffers also provide habitat for wildlife, controls stream temperature (critical to cold-water fish), and is a source for the organic matter needed by aquatic life.

Benefits Of Buffers

Prevent streambank erosion
Filter out pollutants and sediment
Protect groundwater
Improve aquatic habitat
Improve wildlife habitat
Protect against flooding
Add natural beauty
Shield agricultural fields and livestock from wind
Prevent equipment rollovers near sloping shorelines and streambanks

Buffer Widths

The width of buffers is extremely important in controlling for sediment, phosphorus, and nitrogen. Scientific literature supports a minimum buffer width of 100 feet—with 2 more feet per 1 percent slope (Wegner, 1999).

Buffers are also more effective when they are contiguous and are accompanied by nutrient management plans to efficiently use nitrogen and phosphorus.

What Would The Rules Do?

The rules to control polluted runoff would require vegetative buffers: in new developments around lakes, streams, and wetlands; and during the construction of new projects.

Vegetative buffers are proposed as one option to maintain water quality corridors in agricultural fields.

The Clean Water Coalition’s¹ Position On Vegetative Buffers

The Clean Water Coalition supports the requirement of buffers and argues for wider buffers in order to maximize the gains from this practice.

The Clean Water Coalition supports a standard of 20 to 35 feet of buffer along navigable waterways with an additional 30 feet of conservation farming practices.

For new developments, the Clean Water Coalition supports the requirement of 50 to 100 foot buffers for all new developments and 150 feet for high quality water resources.

On transportation related construction, the Clean Water Coalition supports the requirement of 50 to 100 foot buffer zones.

What Can You Do To Help?

Please write a letter to the Natural Resources Board encouraging them to require mandatory buffers along waterways in agricultural fields. The letter should go to:

Natural Resources Board

Trygve Solberg, Chair

P.O. Box 7921

Madison, WI 53707

¹The Clean Water Campaign is funded in part by a generous grant from the Beldon Fund.

For more information, please contact Steph Adams, Clean Water Coalition coordinator.
Phone: 608-441-4811 Email: cleanwater@wisconsinrivers.org