Tuesday, March 2, 2010 • BLM won’t close Bly Tunnel

Publisher’s note: This story is reprinted from the Tuesday, March 2 issue of the Lassen County Times.

Bly Tunnel, connecting Eagle Lake, Murrer’s Upper Meadow and eventually Willow Creek, will remain in its current state.

Despite concerns and complaints from citizens that the flow from the tunnel was contributing to the declining water level at Eagle Lake, the Bureau of Land Management will take no action to close the bypass pipe located in a concrete plug in the middle of the tunnel.

Dayne Barron, manager of the BLM’s Eagle Lake Field Office, appeared before the Lassen County Board of Supervisors on Wednesday, Feb. 23 to announce the federal agency’s decision.

Barron said reviews of earlier environmental documents and consultations with various agencies and experts revealed no new information that would cause the BLM to reconsider its 1985 decision to permanently plug the Bly Tunnel and install the bypass pipe.

The Bly Tunnel was constructed in 1923 to divert water from Eagle Lake to provide irrigation water in the Honey Lake Valley area, according to correspondence from the federal government. The tunnel is 7,300 feet long, extending from the inlet point near Miner’s Point on Eagle Lake in a southeasterly direction to the outlet portal at Murrer’s Upper Meadow and Willow Creek.

The correspondence notes that during the original tunnel construction, “a zone of excessive subsurface seepage was encountered at about 300 feet from Eagle Lake and may be the current source of seepage into the tunnel.”

The seepage caused modifications to the original tunnel construction, and in the 1980s, BLM “constructed a permanent concrete plug at the approximate halfway point in the tunnel,” and “an outlet pipe was built into the concrete plug to accommodate existing private water rights … ”

“We have worked very carefully on this review since late 2008, when we began hearing concerns about the effect of the tunnel plug bypass on the level of Eagle Lake,” Barron said. “We concluded that outflow from the Bly Tunnel bypass is an accumulation of groundwater, including Eagle Lake seepage and that closing the bypass pipe would have little effect on Eagle Lake outflow.”

Barron told the supervisors even if the pipe was closed, he believed the water would simply seep out somewhere else.

He also noted in more than 80 years since the tunnel was created for the failed irrigation project, water in Willow Creek, through which the Bly Tunnel water flows, supports a riparian ecosystem, including fish and plant species, wetlands and wildlife resources.

“Reconsideration of the previous decision by this office was not taken lightly,” Barron wrote. “With approximately 40 percent of the lakeshore public lands, the BLM has a large stake in the lake’s water quality and scenic values, including retention of the natural setting of the lakeshore. The 1985 decision to place a pipe through the plug was based on an understanding of water rights, previous tunnel flows and the hydrology of natural outflow. The significant degree of due process associated with that decision is well documented.”

In a Feb. 22 letter from Barron to Charles Rich, Chief of the Complaint Unit of State Water Resources Control Board, Barron wrote an 8-inch pipe was installed when the plug was constructed to meet the legal rights of downstream property owners authorized to appropriate water from Willow Creek. Since that time, water that has accumulated above the plug, at or above the pipe level, has been flowing continuously through the pipe at varying rates.

According to Barron’s letter, “It has always been BLM’s contention that water exiting the tunnel since 1935 is intercepted groundwater flow that likely includes lake water.”

Critics have complained the seepage from the tunnel has lowered the level of the lake by 36.8 inches over the past 23 years.

“Ultimately, Eagle Lake sets its own elevation based on inflow, not by controlling flow from a pipe which accounts for a small percentage of total lake outflow,” Barron wrote.

The California Department of Fish and Game expressed concern that cutting off the flow could be detrimental to the fish in Willow Creek. In the 87 years since the tunnel was constructed, a fully developed riparian system — including aquatic life — has been created, and some water would need to continue to run through the ditch to avoid adverse impacts to the new ecosystem as well as the ecosystem of Willow Creek.

“I find no basis to begin a process to reconsider water flow through the plug pipe,” Barron wrote in the conclusion of his letter.