Way of the Willow

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Published on: Oct. 2, 1996

Last revision: Oct. 25, 2010

on water treatment plants, but provides critical wildlife habitat, too. It is an example of a win-win situation. Senne's solution works in rural areas. Planting rows of trees, shrubs and grasses along creeks and streams, landowners create buffer strips to help remove soil and chemicals from the water.

Historically, man cleared the fertile riparian areas and converted the land to fields or pasture. Intensive grazing and cultivation removed vegetation from the riparian area, thus removing the roots which held the soil in place. Degradation of soil and water quality resulted. The movement of sediment and stream bank erosion clouded the water and disrupted stream life. Surface runoff also transported chemicals to the streams and groundwater.

For minimal expense and care, riparian buffer strips can be maintained or constructed. Trees, shrubs and grasses maintain stream flow by absorbing excess water runoff, storing it, and releasing it at a later time. For example, riparian buffer strips reduce the severity of downstream flooding by slowing water.

In addition to holding stream bank soil in place during flooding, buffer strips also filter and spread water. Sediments and pollutants from fields are caught in the grasses, trees and shrubs before they enter the stream. And, according to recent studies, riparian buffer strips remove up to 80 percent of nitrogen and phosphorous from runoff and keep it from entering the stream. This reduces the threat of an algal bloom that would consume the oxygen needed by fish and other organisms in the stream.

Wildlife benefits too. The trees, shrubs and grasses provide habitat to a variety of birds and animals. Fish depend on riparian strips for cool water, aquatic vegetation, stream-bank shelters and a constant water supply. Conservation Department personnel periodically monitor Senne's stream. According to Senne, they are pleased with what they have found.

Trees, shrubs and grasses are the three elements of a riparian buffer strip. Depending on soil type and topography, land managers recommend a 60- to 100-foot wide strip along both sides of streams and rivers. Landowners can establish a riparian buffer strip in one of three ways. First, retain or restore native woodlands. Next, supplement native woodlands by planting additional rows of trees, shrubs, and grasses. Finally, plant new trees, shrubs and grasses along streams where little vegetation exists.

The riparian buffer strip should parallel the stream on both sides. To be effective, the Iowa State University Agroforestry Research Team recommends the

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