Stream Solutions...A Landowner's
Guide
Stream Channel Straightening:
Why it's a short-term solution
Living and farming along a stream can provide benefits, but usually not
without a few challenges. Many landowners battle with flooding, stream bank
erosion, field erosion, sedimentation and other crop production-related
problems.
Looking for a quick fix, some landowners decide to straighten a stream
channel. However, this costly solution is only temporary; in the long run it
creates additional problems both upstream and downstream.
Channel straightening replaces a winding stream with a shorter, straighter
channel. The new channel has a steeper slope because water makes the same
elevation drop over a shorter distance. After straightening, the stream must
adjust to these abrupt elevation changes. Water begins to flow faster, causing
increased scour of the streambed and increased bank erosion. As erosion
continues upstream, increasing amounts of soil are deposited downstream. As a
result, streamside landowners are usually faced with more problems after the
project than before they started.
Besides creating more problems, channel straightening is costly to the
landowner, neighbors and local governments. Other low-cost, economically
beneficial solutions are available that don't negatively impact your neighbors
and will provide additional landowner benefits. Inside you'll learn more about
these practical stream solutions that are good alternatives to channel
straightening.
Stream Straightening Costs
The costs for stream straightening are relatively high, both from a
monetary and a societal perspective. Clearing, excavation, and stabilization
costs are the most obvious and easiest to estimate. However, there are also
environmental costs related to stream straightening. Besides the immediate
environmental damage due to habitat loss and downstream sedimentation due to
construction, there are long-term adverse impacts such as increased water
temperature from loss of shading, increased turbidity, increased erosion, and
more difficult fish migration due to increased water velocities.
Adverse impacts to water quality from activities like stream straightening
result in a requirement for the landowner to obtain a permit from the U.S.
Army Corps of Engineers before beginning such a project. If the permit is
approved, it will likely require the landowner to install a series of rock
stabilization structures and/or riffle structures within the stream.
Vegetative buffers and other mitigation measures may also be required by the
permit. Each of these measures will add expense to the project. Costs of these
projects range from about $7.50 to $30 per stream foot.
Stream Solution Alternatives
Not every stream problem is caused by the same situation. Landowners should
carefully evaluate the source of their stream problems before selecting a
management solution. Here are some solutions that may work well for your
operation:
Many stream problems are caused by sediment choking the stream channel or by
runoff that's excessive for the channel's capacity. Soil conservation practices
and stabilization structures will decrease sedimentation and reduce runoff.
Visit your local Natural Resources Conservation Service (NRCS) office for more
information about practices that may help restore the health of your stream.
Some streambank problems are caused when water is directed into the bank by
debris lodged in the channel. Selectively removing debris can reduce erosion;
however, exercise caution not to remove valuable fish habitat. Check with local
officials for help.
When streambank erosion is not caused by obstructions, a structural approach
may be needed. Bank protection measures such as placement of riprap or
re-grading the bank and planting it to erosion-controlling vegetation can
minimize the problem. It is important to note that an eroding streambank on a
straightened stream can rarely be repaired cheaply.
- Installing Vegetative Buffers
One of the most practical stream solutions is to install buffers of grass and
trees along the streambank. These buffers help stabilize the streambanks,
protect water quality, provide wildlife habitat and reduce flood damage. The
buffers also can help straighten field boundaries, simplifying field operations.
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