BLM Closes Bypass Pipe in Eagle Lake Bly Tunnel Plug

The Bureau of Land Management (BLM) Eagle Lake Field Office today closed and locked valves on a bypass pipe that passes through a concrete plug in a failed irrigation project tunnel at Eagle Lake in Lassen County.

In a decision record released today, BLM Eagle Lake Field Manager Ken Collum said the action is consistent with the BLM Eagle Lake Resource Management Plan and BLM water policy.

“The determining factors for me were letters that we recently received from the California State Water Quality Control Board Division of Water Rights and from the California Department of Fish and Game, both reversing earlier opinions on the need for groundwater flowing through the pipe,” Collum said.

“The water quality control board reversed an opinion dating to 1977 and said there are no downstream rights to this water flow. Additionally, the DFG determined that the groundwater seepage from the tunnel is insignificant to downstream fish and wildlife resources,” he said.

He said that based on the state agency opinions, he has determined there is no beneficial downstream use for the water flowing through the bypass pipe.

The 7,000-foot-long Bly Tunnel was completed in 1923 by a private irrigation company attempting to irrigate Honey Lake Valley crops with Eagle Lake water. The water proved unsuitable because of high alkalinity and the project was abandoned in 1935.

The BLM installed a permanent concrete plug at about the midpoint of the tunnel in 1986 to prevent downstream flooding during high water periods in the lake. The eight-inch bypass pipe was installed to allow accumulating ground water to pass downstream.

Details on this action are contained in categorical exclusion and decision record documents available online at www.blm.gov/ca/eaglelake.