Hesperian Health Guides
Restoring Waterways and Wetlands
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The plants and trees that grow along the banks of streams and rivers and in wetlands (areas where the ground is wet or flooded all year), do many important jobs in the watershed. They control floods, clean water, help surface runoff sink into the ground, and provide homes to a variety of animal and plant life.
Streams and rivers in cities and towns are often made to flow in a straight line to control flooding and make it easier to build around them. But the straighter a stream or river, the faster water flows through it. When water speeds up, it causes more erosion of streambeds and banks and is more likely to cause flooding downstream. Floods carry large stones and logs downstream, so even in the dry season you can tell if a river may flood by looking at the size of the rocks and logs in the streambed. If a slow, shallow river has large stones in its bed in the dry season, this is a sign of dangerous flooding that carries these large stones downstream in the rainy season. See Chapter 9 for more information on restoring watersheds.
|This river will flow slower, allowing water to sink into the ground.|
Restoring plant life
Plants that grow along waterways help to slow, spread, and sink rainwater into the ground and hold soil in place.
Plants and trees help rainwater sink into soil, so less runs into the river.
One way to stop soil erosion along streams and rivers is to plant trees alongside them. Planting in an area 20 to 50 meters wide on each side of a waterway will usually reduce erosion.
|Preserving and restoring wetlands is
an important part of watershed protection.
Trees that like to have wet roots grow easily from cuttings. Plant 2 or more rows of cuttings, and then pile brush or branches between the rows. This holds the soil in place and starts to create the conditions for other plants and animals to return.
Trees, shrubs, and grasses may begin to grow on their own once the sides of the river or stream are stable. If they do not, you may want to plant them. If possible, fence the area to keep animals out and to prevent people from gathering wood in the area until trees are fully grown.