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Chapter 7: Human Alterations to Riparian Areas
Channelization
- The process of channelizing a stream includes making it straighter, wider, and deeper compared to what the natural stream used to be.
- Benefits from channelization include: protection from flooding for buildings and other structures along the stream/river.
- Direct impacts of channelization are the destruction of riparian vegetation by the heavy machinery necessary to straighten, deepen, and widen the stream channel.
- Indirect impacts include:
- Deepening of the channel decreases the water table and reduces the frequency of overbank flows making the stream banks and riparian soils much dryer.
- Dryer soils put stress on riparian vegetation.
- stress on native riparian vegetation is a disturbance that often can lead up to the colonization by invasive/noxious weeds.
- The stream’s length is decreased because the stream changes from meandering to straight (Figure 7.8). This increases the stream’s slope that increases stream water velocity and power.
- Streams become flashier, and downstream reaches experience higher peak discharges that increase stream bank and bed erosion.
Figure 7.8. A common practice in the United States; changing meandering reaches (left) into straight reaches (right).
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