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Time to Change Lake Mendo Rules

What's being called California's worst drought in decades has spurred a bill that could compel the US Army Corps of Engineers to rethink the way it runs the Coyote Valley Dam, and how much water can be stored in Lake Mendocino throughout the year.

The Corps runs the dam between November and April based on a decades-old formula — called a rule curve — which, according to local officials, doesn't allow Lake Mendocino to store enough water to ensure a steady supply the rest of the year, but instead releases any water above a flood control limit established more than 50 years ago.

"The rule curve is roughly 50 years old at the Coyote Valley Dam, so the whole release schedule at Lake Mendocino is based on science that old," said spokesman Paul Arden of Congressman Jared Huffman's office. "The releases this summer exacerbated the drought conditions there."

Huffman last month introduced HR 3988, called the "Fixing Operations of Reservoirs to Encompass Climatic and Atmospheric Science Trends Act" (commonly called the "Forecast Act"). The bill would give the Corps three years to do a study to find better ways to operate any of the reservoir projects it runs nationwide at the behest of local entities, according to Huffman's office.

The Corps runs the Coyote Valley Dam during flood control season (November through April) using a formula and graph drawn in 1959.

Based on the graph, called a rule curve, Lake Mendocino can have no more than 72,300 acre-feet in it during those months. (An acre-foot is the amount of water needed to flood an acre of land under a foot of water.) Storage can be ramped up again by April 20 to allow the lake to be at its capacity of 91,000 acre-feet.

The problem with Corps 's 55-year-old formula is that any rainfall prior to November, along with any water released into the lake from the Potter Valley Diversion from the Eel River before April, has to be released over the dam into the Russian River, according to Russian River Flood Control and Water Conservation District General Manager Sean White. That means no matter how much rain falls during flood control season, none of it can be stored.

The bill would allow local sponsors for any of the reservoirs the Corps operates nationwide to request that the Corps update its operating manual for the reservoir based on modern science and weather forecasting, and give it three years to complete a study. As one of the local entities that contributed to the cost of building the dam, the Russian River Flood Control District is a sponsor.

White says that had the Corps used weather forecasting to gage its releases during the 2012-2013 flood control season, the rainfall that year could possibly have been stored. Instead, it was released downstream, and, in the absence of further rainfall, the water level sunk below the 72,300 acre-foot flood control line. Lake Mendocino hasn't even risen to that level since December 2012, according to White.

The Forecast Act, if it passes, could mean the Corps would schedule releases over the dam based on a "rolling five-day forecast," he said.

Not only does the weather change from year to year, but so has the amount and timing of water released to Lake Mendocino from the Eel River in Potter Valley, and the demand on the reservoir from users in Mendocino County and northern Sonoma County.

"I use the analogy of the lake as your bank account," White said. "Your revenue could change, and your expenses could change, but if you never changed your budget, you probably have a pretty lousy budget that looks a lot like the reservoir (Lake Mendocino) does today."

White reported to the Mendocino County emergency drought ad-hoc committee last week that he had met with state representatives and the Army Corps of Engineers for a tour of the dam on Feb. 24.

"I was just really trying to convey the message that, with all of the inputs changing the system, from the changes in Potter Valley to the multiple changes we've had to the release schedule, the only thing that's never really changed is the piece in the middle, which is how the reservoir is run," he said.

The Corps 's current manual for the Coyote Valley Dam does allow changes during drought conditions, but the Corps "can be difficult to work with," according to Mendocino County 1st District Supervisor Carre Brown, who chairs the ad-hoc committee.

White said the purpose of the meeting was to discuss updating the Coyote Valley Dam water release schedule based on modern science and current conditions, either through Huffman's bill or by other means.

"It became very, very clear that they don't really see any need or reason to do that," White said of the Corps staff. "They were red-faced and insistent that, even though the rule curve was drawn in 1959, it's still ... the best technology available today, which ... with the backdrop of an empty reservoir, was sort of a tough pill, I think, for everyone present to swallow."

While flood control has traditionally taken a front seat in the operations at the dam, he said, Huffman's bill could bring balance between that and the questions of water supply and recreation.

"Everything the operation was predicated on is changed ... every single piece of it except the rule curve itself," White said. "But at the end of the day, their insistence was so nonsensical that it ... almost made our point for us."

The Forecast Act was introduced Feb. 4 to the House's Transportation and Infrastructure Committee, and was referred the next day to the Subcommittee on Water Resources and Environment. The next step for the bill is a hearing before the subcommittee, which has yet to be scheduled.


Drought: Groundwater Studies Can Begin Under Mendocino County Water Agency

Well owners needed to step up to participate

A local entity recently stepped up to monitor groundwater in the Ukiah Valley to preserve the valley's access to state grant funding for drought relief, and urges local well owners to volunteer to have their groundwater levels monitored.

A state Department of Water Resources representative told the Mendocino County emergency drought ad-hoc committee last week that Ukiah Valley could lose out on state funding if an entity couldn't be found to do the monitoring, which is required as part of the California Statewide Groundwater Elevation Monitoring program.

According to a Wednesday announcement from the Mendocino County Resource Conservation District, the Mendocino County Water Agency applied to be the approved monitoring entity for Anderson Valley, Round Valley, Sanel Valley and the town of Mendocino, but not for the Ukiah Valley.

"The county was aware of the gap in information and joined forces with the conservation district to provide the data collection," conservation district Executive Director Janet Olave said in the prepared statement. "What we need now is for private well owners to come forward. The process is simple and requires no effort on the part of the well owner. It is an easy way to contribute a huge public service."

The monitoring is a prerequisite for state funding for water project, which, according to Olave, "may include drought relief funding."

The monitoring program needs the cooperation of private well owners to allow local entities to conduct semi-annual visits to monitor groundwater elevation, according to the conservation district. The program's goal is to gage seasonal and long-term trends in groundwater levels within each of the state's monitored basins. The data will be made available to the public in a statewide database, conservation district stated.

The Department of Water Resources ranked California's 515 groundwater basins and subbasins as very low, low, medium and high priorities. The state is focusing on high- and medium-priority basins for state water grants or loans.

The Ukiah Valley was identified as Mendocino County's only medium-priority basin.

Out of the state's 515 groundwater basins, 126 are ranked medium- and high-priority. In the North Coast hydraulic region, there are no high-priority basins and eight ranked medium priority, including the Ukiah Valley.

To have the groundwater at your well evaluated, call Janet Olave at 462-3664, or email her at

(Courtesy, the Ukiah Daily Journal.)

One Comment

  1. Rick Weddle March 13, 2014

    A note of caution about asking, or letting, the Army Corps of Engineers anywhere near your water…or anything else of value:

    “Dams and Other Disasters; A Century of the Army Corps of Engineers in Civil Works” by Arthur E. Morgan, lst head of the TVA.

    If you’ve not seen this, it’ll surely stand your remaining hair up.

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