8141A

• UCREFRP Catalog Number: 8141A
• Author: Wydoski, R. S. and W. T. Helm.
• Title: Effects of Alterations to Low Gradient Reaches of Utah Streams.
• USFW Year: 1980.
• USFW - Doc Type: \
• Copyright Material: NO

RECOMMENDATIONS

In the flood plains of streams in the Intermountain West, reduced stream
flows during the summer result from irrigation diversions on all major streams.
Therefore, the effect of stream alterations on physical conditions and fish
and macroinvertebrate populations must be considered jointly with reduced
streamflows.

Although landowners in the flood plains of rivers alter stream channels
to prevent flooding, their short reach alterations do not last long--usually
less than one year. Landowners are frustrated by upstream activities that
produce stream erosion and deposition, and the lack of comprehensive programs
to stabilize the entire stream system. Three programs are needed to prevent
continued damage to and destruction of streams: Comprehensive basin-wide
plans to regulate stream channel changes so as to minimize damages to other
landowners and to the streams; research to identify methods of controlling the
height of the water table under agricultural land with minimal effects on
streams; and an effective information and education program to educate owners
of river bottom land about the hydraulics of the river in a flood plain, the
consequences of altering streams and producing unstable conditions in the
altered area and downstream, and alternative ways to prevent flood damage to
crops.

Between 1955 and 1970, fishing increased 37 percent in the Mountain States,
and this trend is expected to continue. It is believed that over 80 percent of
prime trout stream habitat has been severely degraded or eliminated in Utah.
Because channel alterations may be irreversible or cause unstable streambeds,
engineers and biologists should work jointly so that the necessary changes to
the stream environment would result in the least damage to fish and wildlife
habitat. Perhaps, through this kind of interaction, stream alterations could
be made that would sometimes improve habitat for fish and wildlife.

This study demonstrated that pools were vital to survival of brown trout
and mountain whitefish during low streamflows. Alternatives to channelization
must be evaluated so that pool environments are not completely eliminated as
happens with typical stream channeling practices.

Dewatering which results in loss of pools, or ineffective scouring of
pools during spring runoff, has an effect similar to channel alteration.
Minimum streamflow regulations are needed to protect fish populations.

Improve~ent of the law regarding alteration of stream environments is
desperately needed in the Intermountain West where streams are not plentiful
and are being damaged by various kinds of water resource development. A
single agency or a coordinating council should review permit applications for
stream alterations and should monitor and evaluate channel modifications so
that control of the accumulated effects can be managed on a watershed basis.
Land use planning that involves the entire river system should be manditory.

Descriptions of the microhabitat requirements of key fish species should
cover the various life stages during various seasons. This critical infor-

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