Environmental Impact Statement released for proposed reservoir near Hyattville

WORLAND – Last week the Bureau of Land Management Worland Field Office released the Final Environmental Impact Statement (EIS) for the Alkali Creek Reservoir Project near Hyattville.

The proposed project, from the Wyoming Water Development Office (WWDO), supports the BLM's commitment to modernizing infrastructure and is consistent with Wyoming's 2015 Water Strategy.

According to the EIS, "After eight years of conducting studies and scoping, the WWDO determined locations in Wyoming that need reservoirs. The WWDO is proposing to develop a water storage reservoir on Alkali Creek to reduce late-season irrigation shortages. Initial hydrologic modeling and investigation results for the Paint Rock Creek watershed and the lower Nowood River simulated annual irrigation shortages of 9,842 acre-feet during normal hydrologic years (these shortages assumed current idle permitted acreage was put into production).

"Subsequent refinement of the hydrologic model simulates annual irrigation shortages of 2,360 acre-feet and 6,030 acre-feet on average under current conditions and for currently idle permitted acreage, respectively. For these shortages or need evaluations, a historic consumptive use analysis and a surface water allocation model representation of the Nowood River watershed were developed. Currently irrigated lands were determined from aerial photography, and currently idle but permitted lands were determined from Wyoming State Engineer's Office records and subsequent analysis with the hydrographer-commissioners involved in the day-to-day regulation of water in the watershed."

According to the EIS, an irrigation shortage is the difference between irrigation demand and irrigation supply. The irrigation demand is the required amount of water that a crop needs beyond what it receives from precipitation. This value is calculated and is a function of a variety of parameters including climate conditions, crop types and acreages, and soil parameters. The irrigation supply is the amount of water delivered to the crop and is simulated based on stream flow records, ditch capacities, system efficiencies, return flows, reservoir capacities and evaporation, and water rights.

The proposed Alkali Creek Reservoir is approximately 3 miles northwest of Hyattville, in Big Horn County.

Alkali Creek is an intermittent creek that flows into Paint Rock Creek, which is a tributary of the Nowood River, all of which are in the Nowood River watershed.

The proposed construction would create a reservoir on Alkali Creek. The reservoir would have a capacity of 7,994 acre-feet at normal high-water level (NHWL) or 2.6 billion gallons of water. The reservoir area would inundate approximately 294 acres of land when it is at normal high-water level. Four roads would need to be built as part of the Proposed Action. The roads would comprise two temporary roads for construction and two permanent access roads.

The proposed construction of a dam and reservoir on Alkali Creek would overlap both private and BLM-administered lands.

The reservoir is intended to provide late-season irrigation water for portions of the Nowood River watershed. The reservoir is also intended to provide recreation opportunities through a minimum pool, provide flood attenuation, improve downstream water quality, and provide both direct and indirect economic benefits to the local community and state.

During the study for the EIS, three main alternatives were considered with the proposed alternative being the construction of a new reservoir. This would include a reserve pool for a fisheries and recreation activities. Additional features of the proposed alternative would include the construction of a parking area and boat ramp and the expansion of the existing Anita Ditch and Anita Supplemental Ditch.

IMPACTS

According to the EIS for the proposed action, the primary existing land use in the analysis area and surrounding region is agriculture, including irrigated crops and livestock grazing. Recreation, consisting of hunting, fishing, hiking, off-road vehicle use, and camping, is also prevalent in and near the analysis area. The analysis area comprises 362.4 acres of BLM-administered land and 444.4 acres of private land.

There is 454 acres of federal oil and gas minerals in the analysis area (but no active oil and gas leases) and 230.5 acres of mining claims. There are no energy corridors, BLM pipeline rights-of-way (ROWs), BLM power and transmission ROWs, or any other BLM ROWs in the analysis area. ROWs are present on private lands. WYDOT holds an easement along Wyoming Highway 31 that would be avoided by the proposed temporary bypass pipeline. Big Horn County currently does not have county-wide zoning regulations, but does require permits for construction and development.

According to the EIS, regarding environmental effects it was found that "construction activities and associated traffic under the Proposed Action would increase emissions in the analysis area from vehicle exhaust and fugitive dust. These minor increases would be localized and temporary during construction and limited to surrounding counties of Washakie, Sheridan, and Johnson."

Regarding land use, "Under the Proposed Action, surface disturbance from the project would affect or prevent certain land uses in the analysis area. Approximately 91.9 acres of existing oil and gas leases and 230.5 acres of existing mining claims would be affected by the proposed surface disturbance. Surface disturbance from the project would prevent potential future mineral leases or rights-of-way on the 362.4 acres of BLM-administered land in the analysis area. Surface disturbance from the project would prevent potential future mining and other land uses on the 444.4 acres of private land in the analysis area."

NEXT STEP

The proposed Alkali Creek Reservoir requires approvals from the Bureau of Land Management (BLM) Worland Field Office (WFO), the U.S. Army Corps of Engineers (USACE), and the Wyoming Department of Transportation (WYDOT).

The BLM Worland Field Office has prepared this environmental impact statement (EIS) pursuant to NEPA (National Environmental Policy Act) to analyze the potential direct, indirect, and cumulative effects of potentially granting a ROW, a CWA Section 404 permit, and a highway encroachment permit for the construction and operation of the proposed Alkali Creek Reservoir and the construction of associated roads and other structures.

The BLM's and U.S. Army Corps of Engineers' decision will be communicated through publication of a single record of decision.

The final EIS and other project information is available at: https://go.usa.gov/xUsam.