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Managing Iowa Acreages: Buffer Your Banks

Native trees, shrubs and grasses in this riparian buffer reduce sediment and other pollutants from entering a stream. If you have a pond, lake, stream or other surface water on your property, it is important to keep that water clean. Reduce sediment, organics, nutrients, pesticides and other contaminants from running off into and polluting water.

The space alongside streams, lakes and wetlands is called a riparian area. Areas of vegetated land adjacent to water that intercept undesirable contaminants from runoff before they enter the water are called riparian buffers. Riparian buffers help control pollution and improve water quality. They are the native grasses, trees and shrubs that grow along the water’s edge that control erosion and help keep water clean.

Native plants and grasses have deep root systems that help absorb storm water pollutants, and assist in bank and slope stabilization. Try to commit at least 10 feet of space along the water’s edge to riparian buffers. Generally, wider riparian buffers provide better wildlife cover and better fish habitat.

Buffers should serve as a final filtering out of sediment, fertilizers, pesticides and other pollutants before runoff enters the water. Upland, infiltration-oriented practices, such as native landscaping, soil quality restoration, rain gardens and bioswales should infiltrate much of the initial runoff.

Benefits of Buffers

Improve fish and wildlife habitat. Although riparian areas comprise a small portion of the landscape, they represent critical habitat for a diverse range of living creatures, including wood ducks, songbirds, frogs, insects and a variety of aquatic organisms. Keeping these areas healthy with good vegetation will provide food and cover for wildlife.
Reduce flooding and soil erosion. Riparian buffers reduce erosion by slowing water movement, helping to stop embankments from cutting and eroding.
Reduce water pollution. Healthy riparian areas filter out sediment, fertilizers, pesticides, pathogens, and other potential pollutants from streams and rivers.
Allow the soil to hold more water. Native vegetation holds more water in the soil, slowly releasing it for longer season stream flows and groundwater recharge.

Stabilize Stream Banks

Without the proper vegetative protection, stream banks begin to down cut and become vertical, bare banks. When stream banks are too bare and vertical, water levels tend to bounce up and drop back down, sawing at the toe of the vertical bank, causing heavy soil erosion, polluting water, covering fish habitat and threatening property. Bare stream banks do not benefit as much from buffers, either.

To stop downcutting of a stream bed, a structural approach may be needed. Stream banks may need to be sloped back to a stable angle (3:1 or flatter); the toe–which lies at the bottom of the slope and supports the weight of the bank–needs to be armored; and then deep-rooted native plants and grasses need to be established on the banks.

If you have a pond that needs buffered or a stream that needs buffered or repaired, contact your local USDA-NRCS office for information about pond and stream protection options.