Restoration of Fish Habitat in Relocated Streams
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interest of information exchange. The United States Government assumes no liability for its
contents or use thereof.
The contents of this report reflect the views of the Office of Development of the Federal
Highway Administration, which is responsible for the facts and the accuracy of the data
presented herein. The contents do not necessarily reflect the official views or policy of the
Department of Transportation.
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Occasionally, in constructing a highway, it may be necessary to encroach on a natural stream, or
even to relocate the channel. In this event, the Federal Highway Administration believes that
every effort should be made to restore the stream to a condition equal to that in which it existed
before the highway construction.
This manual provides guidelines for the design and construction of relocated channels, and
describes measures that will lead to rapid recovery of new channels by natural processes. Good
design, and implementation of these measures can greatly reduce the adverse effects of stream
The literature on stream relocation and restoration is widely scattered in special reports and
periodicals of limited circulation. In 1976, under a contract with the Federal Highway
Administration, Dr. James R. Barton, of Brigham Young University examined the literature, and
made extensive field studies of channel relocations in 12 States. This manual has been
developed by Dr. Barton from these researches. Mr. Frederick W. Cron, of Lakewood, Colorado,
assisted in the preparation of the text.
Over the years, rivers and streams have been straightened, shortened, diverted, encroached upon,
cleaned out and altered for many reasons. The consequences of this interference with nature
have often been increased erosion and sedimentation, deterioration of aquatic life and a general
loss of natural esthetics. However, these undesirable results are not inevitable. If good hydraulic
design and construction practices are followed, a relocated stream can in time recover its
esthetics and its value as a fishery.
Highway Locations in Stream Valleys
River and creek valleys are natural locations for railroads and highways because they generally
require less cut and fill than other routes. However, they are ecologically fragile and easily
damaged by construction, particularly construction which encroaches on the stream channel.
Ideally, highways should be located to leave undisturbed ground between the road slopes and the
watercourse. However, this is not always possible, and it may occasionally be necessary to
encroach on the stream, or to cross and recross the channel.
Formerly, it was standard practice to divert streams into new channels in order to occupy the
natural channel or reduce the number of culverts and bridges needed. It was easier and cheaper
to improve the road alignment this way than to increase cuts and fills or build the additional
structures. Preservation of fish habitat and stream esthetics received little attention, if, indeed,
they were considered at all.
Concern for the whole highway environment now requires more thorough studies before streams
are moved or disturbed. These studies should consider esthetic and natural values as well as
construction, maintenance and operating costs. These evaluations should be made during the
initial location of the highway, or, for an existing highway, before major relocations or
improvements are undertaken.
Location by Interdisciplinary Teams
The modern trend is for highway locations to be made by teams combining the viewpoints and
talents of a number of disciplines. Where there is a possibility that the location may encroach on
the flood plain of a stream or require relocation of the channel, the team should include a
hydraulic engineer and a fisheries biologist. The location team should study alternate locations,
including one avoiding stream changes.
In the evaluation process the team should consider potential damage to the stream ecosystem.
The highway engineer determines the probable encroachments on the stream due to construction.
The hydraulic engineer estimates channel capacity and the possible effects of the highway's
encroachment on the flood plain. The fisheries biologist determines fish populations, and
estimates their ability to survive or recover from the physical impacts of construction. The
landscape architect recommends measures to restore the esthetics of the area. As a group, they
combine ideas and solutions to produce a plan that will fulfill the engineering requirements for
the highway with the least damage to the stream.
When stream relocations are necessary, they should be as carefully planned and constructed as
the highway itself, using the interdisciplinary approach. This means providing a stable channel
of adequate hydraulic capacity, and naturalizing the new channel by restoring fish habitat and
planting trees and vegetation to regenerate the original bank conditions as rapidly as possible.
The following chapters will review principles and practices that have proven effective for
restoring natural conditions in relocated streams with coarse material beds. In such streams
adherence to these measures will greatly reduce losses of environmental quality caused by