Grand Teton National Park
Evaluation of Jackson Lake Dam on the Snake River
PROJECT NUMBER 2002-0311-010.2
NFWF & JHOF Partnership: $10,000
Local Match: $10,000
Grand Teton National Park was established to protect the area’s native
plant and animal life and its spectacular scenic values, as
characterized by the geologic features of the Teton Range and Jackson
Hole. The parks’ Strategic Plan highlights the significance of the Snake
River as habitat for cutthroat trout and as a recreational resource,
along with the abundant mammal, plant and bird species that reside in
the park. The parks 1997 Snake River Management Plan emphasizes the
desire to maintain the river’s natural character in order to protect
wildlife and scenic values.
The Jackson Hole One Fly Foundation - National Fish and Wildlife
Foundation Conservation Partnership Program is funding this project to
investigate the quality and quantity of riparian and aquatic habitat
critical for fish and wildlife. The outlet of Jackson Lake was dammed in
1906. The
 original
dam was then replaced by a larger structure in 1918 that raised the lake
level by 11.9 meters. The reservoir has since been operating to provide
irrigation water to areas in Idaho during the summer. In 1957 the
Palisades Dam closed and its reservoir became the primary storage
facility for irrigation and agriculture. This changed the functions of
the Jackson Lake Dam and caused the release schedule to decrease in
frequency and magnitude. These changes altered the flow and triggered
channel changes and vegetation destruction. Recent studies have shown
that the decrease in velocity of the main channel has caused accelerated
deposition of bed materials and has eliminated numerous side channels,
which formerly served as spawning and rearing habitat for cutthroat
trout.
Project Status:
Personnel from the Wyoming Game and Fish Department (WG&F) have entered
historical field data into a database and have completed their summary
of the Jackson Lake Fisheries. A reconnaissance of Jackson Lake was also
performed and they were able to identify the locations of annual netting
operations currently being performed and address ways to better netting
practices. They also looked at the affects of the dam on hydrology and
geomorphology and analyzed the hydrologic change and variability that
has occurred on the Snake River during the last century.
For more information, contact: Susan O’Ney,
Susan_O’Ney@nps.gov,
307-739-3666.
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