Grand Teton National Park, the National Elk Refuge and Trout Unlimited propose to remove an aging diversion dam on the Gros Ventre River at Kelly, Wyoming. The Newbold dam impedes native fish passage, and in its current condition, will likely fail during spring runoff. Grand Teton is beginning to analyze potential impacts of the dam's removal and will develop an environmental assessment (EA) if it is determined to be an historic resource. Public comments will be considered for this project and the scoping period will be open from December 5 through January 11, 2013.
Grand Teton acquired the Newbold diversion structure in 1949, along with headgates, irrigation ditches and all associated water rights. The dam, a low-head log and rock structure, has eroded to the point that failure is inevitable. Its current failing condition is illustrated by the adjacent photograph taken November 16, 2012.
The Newbold dam has been identified by the National Park Service, Wyoming Game and Fish Department and Trout Unlimited as an impediment to natural movements of native cutthroat trout and non-game fish, particularly bluehead sucker, a state-listed sensitive species. Both species have declined in distribution and abundance across their range. The diversion dam is the only barrier to upstream migration between the Snake River and numerous miles of upstream Gros Ventre River and tributary habitat. Recent radio telemetry movement studies indicate that some adult trout are able to pass the low-head dam; however others, including smaller trout, native suckers, and small non-game fish, are unable to cross the barrier. The Newbold dam could also pose a safety hazard to people fishing downstream should the diversion structures suddenly fail.
Because dam failure could affect the structural integrity of a bridge about 650 feet upstream, consultants from the NPS Water Resources Division (WRD) and Trout Unlimited recommend a controlled removal.
Trout Unlimited proposes to raise funds and contract for the removal of diversion structures during the spring of 2013 in partnership with Grand Teton National Park and the National Elk Refuge. After removal, some bank restoration and revegetation would occur, including re-contouring the project access area.
Primary issues to be resolved during analysis include: determination and mitigation of potential effects of downstream dam removal on the upstream bridge; completion of an evaluation on the dam and associated ditches for their eligibility as historic resources; and attainment of cultural resource compliance with the State Historic Preservation Office, if structures are deemed historic.
To obtain information and submit comments, visit online at http://parkplanning.nps.gov/grte/newbold. Comments may also be submitted to Grand Teton National Park; Attention: Carol Cunningham; P.O. Drawer 170; Moose, WY 83012.
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