The Office of Energy Projects at the Federal Energy Regulatory Commission on Feb. 3 issued the final environmental assessment related to an application for an original license to construct the Coleman Hydroelectric Project, located on Little Timber Creek near the Town of Leadore in Lemhi County, Idaho.
In April 2011, Coleman Hydro LLC filed an application for an original license on this project. It would have an installed capacity of 750 kW and would use water currently being diverted from Little Timber Creek by two existing irrigation diversion structures.
The proposed project would consist of the following new facilities: an approximately 60-foot-long, 15-foot-wide, and 6-foot-tall concrete diversion and intake structure partially extending into Little Timber Creek; a trash rack with 2-inch bar spacing connected to the intake; two 12-foot-long rotating-drum fish screens located at the intake and a fish bypass pipe running from the intake to Little Timber Creek; a 26,700-foot-long penstock running from the intake to the powerhouse made of 20 to 30- inch-diameter plastic or steel buried pipe; a 20-foot-wide, 24-foot-long, 11-foot-high powerhouse containing a single 750-kW Pelton turbine/generator; and a 6.7-mile-long, 12.5-kV transmission line that would interconnect with an existing Idaho Power 69-kV transmission line.
The proposed project would be located on Little Timber Creek, several miles upstream of its confluence with Big Timber Creek, which is a tributary to the Lemhi River. Big Springs Creek, also a tributary to the Lemhi River downstream of Big Timber Creek, flows parallel to the Lemhi River for approximately 5 miles. Big Springs Creek receives groundwater return flow from adjacent land in the area that would be affected by the proposed project. The prevailing direction of groundwater flow in the project area is from the southwest to the northeast, toward Big Springs Creek.