“And it is
very, very forward looking” with population
growth and other issues pushing up demand for a
limited water supply, Peterson said. And many
say climate change – warming -- is advancing and
will bring earlier runoff (escapement of water
held in mountain snowpack) and drop river flows
later in the summer season.
proposed dam at the Weiser River-Galloway site
would hold back nearly one million acre feet of
water and inundate 6,918 acres of land. A small
irrigation diversion dam has been in place at
the proposed site for more than 100 years,
Peterson said. The Galloway diversion dam was
named after a member of Idaho’s territorial
legislature who was an early Weiser area
is located 13.5 miles east of the city of Weiser
and the Weiser River’s confluence with the Snake
River. Wild Snake River steelhead, fall and
spring/summer chinook and sockeye salmon are
protected by the Endangered Species Act and
targets for recovery efforts.
dam and reservoir, the planners say, would help
boost the region’s power supply, provide flood
control and irrigation water, expand
recreational opportunities and firm up
availability of water for flow augmentation to
improve conditions downstream for migrating
salmon and steelhead.
bottom line is that this project is huge when it
comes to salmon recovery in the Columbia River
basin,” Peterson said.
Weiser-Galloway site was first studied after the
U.S. Army Corps of Engineers received
authorization from the U.S. Senate’s Public
Works Committee in 1954. Studies were also
advanced in the 1970s and 1980s but the time
apparently was not right, Peterson said.
recently the Corps, which was hired by the
state, completed a comprehensive review of
earlier studies, including a rigorous analysis
of what gaps in information that would need to
be filled before deciding whether to move
forward with comprehensive new environmental,
engineering and economic feasibility studies.
Weiser-Galloway Gap analysis, Economic
Evaluation and Risk-Based Cost Analysis Project
was completed this spring under the Corps’
Planning Assistance to States authority.
issues emerged from the Corps review, the need
for: 1) Coring, analyzing, mapping and seismic
evaluation of the geologic structure and
surrounding faults to determine the safety,
suitability and integrity at the dam and
reservoir site, and 2) analyzing operational
scenarios to confirm and quantify the extent of
potential project benefits.
A range of
operating scenarios will be analyzed in order to
develop a plan that optimizes flood control,
hydro, storage, irrigation, recreation and flow
augmentation while maximizing economic benefits,
according to a fact sheet prepared for the IWRB.
studies would be conducted jointly by the state
and coordinated with the Idaho Power Company,
Bureau of Reclamation, Bonneville Power
Administration and NOAA Fisheries Service. The
studies are scheduled to be completed by
and rock-fill embankment dam itself would be
about 300 feet high and 2,200 feet long. Total
costs could range up to $500 million (2011
called the estimated $350 to $550 per acre-foot
storage capital costs “the most economical large
storage project” that could be built.
reservoir on the Weiser River would provide
economic benefits to the water storage systems
on the Boise, Payette and upper Snake rivers
through potential substitution and relief of up
to 40,000, 160,000 and 200,000 acre feet of
water now released respectively from those
basins to meet anadromous fish flow augmentation
requirements,” the IWRB fact sheet said.
augmentation benefits for the lower Snake,
including reducing Dworshak drawdowns, and
firming up availability of water for flow
augmentation and fish recovery” is another
benefit, the fact sheet says.
the addition of more on-demand water supply
would increase flexibility of flood control rule
curves at Brownlee Dam, possibly resulting in
additional power generation there, and provide
hydropower management benefits for the Hells
Canyon Complex and lower Snake/Columbia river
hydro systems. Brownlee is one of three Idaho
Power Company hydro projects on the lower Snake
that make up the Hells Canyon Complex.
board’s charges is to provide financial
assistance for water development and
conservation projects. The board makes loans and
grants from two accounts, water management and
revolving development. A third account, the
Aquifer Planning and Management Fund, was added
by the Idaho Legislature in 2008. That account
was established to fund technical studies,
facilitation services, hydrologic monitoring,
measurement and comprehensive aquifer planning
Legislature, in a House Joint Memorial,
encouraged the IWRB, in coordination with other
public and private entities, to initiate and
complete the study of additional water storage
projects in the state including, but not limited
to, the study of the potential benefits for the
Galloway Dam surface water storage project.
last Friday authorized its chairman to execute
necessary agreements or contracts to carry out
the geologic and operational investigations and