9587

• UCREFRP Catalog Number: 9587
• Author: Ayres Associates.
• Title: Environmental Permitting Services - Elkhead Reservoir and Yampa River Basin, Colorado.
• USFW Year: 1997.
• USFW - Doc Type: Ft. Collins, CO.
• Copyright Material: NO

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Gradient Restoration Facility, Sacramento River
Hydraulic Design and Environmental Studies

Glenn-Colusa Irrigation District
U.S. Army Corps of Engineers
Sacramento, California

The Glenn-Colusa Irrigation District (GCID) operates a 3,000 cfs diversion pumping facility on
the west bank of a side channel to the Sacramento River at River Mile 206. In conjunction with
the GCID diversion, the California Department of Fish and Game designed, constructed, and
now operates a fish screening and bypass operation on the riverward side of the GCID forebay.
In the early 1970's a bendway cutoff downstream of the facility decreased the length of the
river by 1-3/4 miles, creating adverse impacts to the operational characteristics of the fish
screening activity. Restoration of the pre-cutoff hydraulic conditions via the construction of a
Gradient Restoration Facility (GRF) was proposed. Due to environmental and recreational
values of this section of the river, any proposed modification must avoid the creation of adverse
environmental impacts and barriers to fish passage and recreational boating uses.

Ayres Associates was selected by the U.S. Army Corps of Engineers - Sacramento District to
provide interdisciplinary project team management for the analysis and design of the GRF.
Design features of the GRF are directly related to new fish screening technologies being
designed and evaluated by the U.S. Bureau of Reclamation. Consequently, Ayres project team
members have been involved in Technical Advisory Group meetings with representatives from
a variety of governmental agencies and interest groups.

Ayres is providing primary engineering design and preconstruction services for the project,
supported by Jones and Stokes Associates, Inc. (environmental and fisheries issues), and
CH2M-Hill (geotechnical and structural design) to develop a Design Memorandum for the GRF.
Included in the analysis and design services provided by the Ayres team are: Hydraulic and
hydrologic analysis; Floodplain delineation; Geomorphologic studies; Geotechnical
investigation; Environmental assessment; Hydraulic design; Alternatives evaluation;
Topographic and hydrographic surveying; 2-dimensional hydrodynamic modeling; and
Preparation of cost estimates using M-CACES.

Noteworthy Features of this Job

· Ayres developed the "design riffle" concept for creating naturally-occurring hydraulic
conditions while restoring the pre-cutoff river gradient.
· Full-service multidisciplinary consulting team provided comprehensive response to a wide
spectrum of issues and concerns.

Why is this Job Relevant?

· Project involved complex engineering analysis, design and environmental assessment
within a multi-agency setting.
· Mitigation of impacts to Threatened and Endangered species was a focus area.
Recreational considerations were included in restoration of pre-cutoff riverine environment.