University of Wisconsin - Extension

Perhaps no part of the rural landscape offers more variety and valuable functions than the natural areas bordering our streams.

"These unique stream 'corridor' lands help filter pollutants from runoff, lessen downstream flooding, and maintain stream base flows," explains Gary Korb, University of Wisconsin-Extension regional planning educator. "They also provide a variety of recreational opportunities and habitat for fish and wildlife with their rich ecological diversity."

No matter how small a stream may be, the land around the stream is important to the environment. But many of the stream corridors no longer fulfill their potential due to the encroachment of agriculture and suburban development.

Stream corridors serve as water quality connections. "A natural stream corridor can protect the physical characteristics of a stream while improving its water quality," adds Korb. "A wide strip of vegetation prevents soil erosion in shorelands and can help stabilize weakened banks - two of the sediment sources otherwise most likely to pollute a stream."

Thick and grassy vegetation serves as a filter for eroded soil and other pollutants carried by runoff water. Heavy rains or melting snow can pose the greatest risks for bare stream sides. Permanent stream corridor vegetation allows more water to soak into the soil, creating more soil filtering and recharging of the groundwater.

A lush stream corridor also preserves and attracts wildlife. "Waterfowl will frequent stream corridors and nest in the natural cover," adds Korb. "Kingfishers, herons and other fish-eating birds will take advantage of the healthy fishery. Fox, mink and other smaller mammals often live or feed along banks and backwater areas. Turtles, frogs and salamanders also populate shorelines and provide an important food source for other animals."

Deer will bed down in the thicker cover. Hawks and owls monitor such areas for their next meal. Game birds, including pheasant, grouse and quail, often thrive along natural stream corridors. Songbirds and butterflies enjoy the tall grasses, wild flowers and fruits of shrubs and trees.

"Environmental Corridor" is gaining widespread recognition as a term for the most important of our remaining natural resource areas, adds Korb. "Often, these occur along streams and lakes where agriculture or urban development has not eliminated the natural vegetation or landscape. Primary environmental corridors, especially, have regional importance and should be protected at great lengths."

A good example of their definition was originally advanced, and has been used for decades, by the Southeastern Wisconsin Regional Planning Commission: a minimum size of 400 acres, 200 feet in width and two miles in length.

Owners of land that borders a stream or other water resource can make a big difference for the local environment. If a natural corridor exists now, do what you can to protect it. If the stream corridor is degraded, consider the following guidelines:

• Mark off an area 50 to 100 feet wide between farmland or open land and the adjacent stream, lake, pond or wetland. Look for logical boundaries, including sudden changes in slope or the chance to ?even out? irregular fields.
• Fence out livestock and don?t plant crops there.
• Stabilize any erosion by establishing a permanent cover of vegetation as soon as possible. Native grasses and forbs are preferable, with a nurse crop sometimes helpful to get things going.
• Over time, try increasing diversity by planting native trees, shrubs, wild flowers and grasses. Generally maintain a natural pattern and appearance, while enhancing the area for your enjoyment.
• Develop and follow conservation plan for adjacent land. This will reduce sediment and other pollutants in runoff and also preserves soil for the long-term productivity of your land.

Public assistance for planning, planting and even shoreline easements or rent may be available for carrying out these guidelines. For more information, contact your UW-Extension county community resource development educator or land conservation office.