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Wetland plants, such as rushes and grasses,
act as a water barrier.
Wetlands can soak up a lot of water. When water floods out of a
river channel into a wetland, the wetland soil and plant roots act like
a sponge. The wetland reduces the amount of water flowing down the
river channel. The wetland holds the water for a while. Then the water
slowly seeps back into the river channel. The total flow of water going
down the river is not reduced by very much. But the wetlands and
floodplains slow the flow rate of the water in the channel. And this
reduces the effects of the water as it flows downriver. Wetlands and
floodplains help to reduce erosion and lower the level of floods.
The wetland plants slow the rate of flow in another way. Plants such
as rushes and grasses provide barriers. The water must flow around and
over the plants. This reduces the speed of water flowing down the main
river channel.
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