Think about where the streams are near to your home, neighborhood, or park. Are the stream banks covered with herbaceous plants and shrubs, like purple coneflower and buttonbush and are they overhung with a variety of stately trees such as willow and sycamore? When you walk down the gently sloping streamside, also known as the flood plain, and get closer to the stream can you see minnows swimming in clear water, water boatman striding on the surface, and dragonflies hovering above? Looking down, do you see all the way to the bottom, where there are mixed cobbles, pebbles, and smaller grains of sand in the streambed? Imagine then lifting up a rock. Did you find a or other small creatures, making their homes and raising their families in the bottom sediments? If you can say, "yes" to most or all of these questions then this stream would definitely be called a "Healthy" stream.
Straight Talk about Curvy Streams
Healthy streams also meander naturally. And when they do, natural erosion occurs on the outer curve where the water has a higher velocity and flows more swiftly. Then this loose material is transported by the water and ends up as natural deposition onto the inner part of the curve where the water slows down. In this way, streams form their bank patterns, including sand bars and islands. When there is a rainstorm event, the erosion, transportation, and deposition increase proportionally, depending on the intensity of the storm. So the stream's configuration may change temporarily, but ultimately, all streams are trying to reach their best equilibrium, even though they are always dynamic in energy flow.
Unfortunately, not all streams are healthy because they have not been allowed to maintain their natural, meandering state. Many streams have been degraded by human attempts to straighten or channel them for convenience sake, either for agricultural, residential, industrial, or municipal development purposes. When streams are forced to flow in a straight channel, the velocity increases dramatically due to the increased volume. When the velocity increases, so does the erosive power, and the stream cuts down its own banks and or bottom. This increased erosion leads to increased suspended sediment in the water, greater turbidity or muddy water, and greater sediment deposition and disturbance in the bed. Muddy water effectively stops photosynthesis because light cannot penetrate down to the aquatic plants on the bottom. Also, the available oxygen also decreases. Then the animals not only lose their food source, but also their air to breathe, and their hiding and nesting habitat.
Living on the Edge?
Channeling is not the only way that we disturb our streams. Every time that we mow our lawn right to the edge of the stream, or cut down "weeds" and bushes or trees on the bank, we impact stream health. The roots of all these water-loving plants hold the soil in place and stabilize the banks. These roots also filter out pollutants from our storm water and provide a barrier to pollution in the stream. When it rains, pollutants wash off over the land in the largest amount at the very beginning of the storm.
When we modify our streams and leave areas along streams, also called riparian areas, unprotected we also increase the risk of flooding. With its natural width, depth, and volume, the stream can hold water all the way to bank full, or on its floodplain, and the natural vegetation absorbs a huge amount of water in the roots and the stems (or trunks) and leaves. If we remove the natural containment capacities of streams, and fill or build on floodplains, we leave our fellow creatures and ourselves in a very vulnerable predicament.
Be a Conservation Crusader today! You have the power to help protect and create healthy streams around your home and neighborhood:
*Locate homes and buildings away from flood plains;
*Leave an un-mowed buffer area along streams;
*Compost or mulch yard waste rather than dumping it in a stream or river;
*Ask your community leaders to consider the establishment of riparian buffers as a necessary practice during all new construction and re-development projects;
*Help slow down water from large storm events by installing rain barrels and rain gardens; and
*Plant trees and perennials to help absorb water in the ground and hold water temporarily on leaves.
Need a hand? Contact your local county soil and water conservation district for more information and technical assistance.