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Raising Coyote Dam

Last night representatives from the local water agen­cies met to hear a presentation by the Corps of Engineers on its plans for the Coyote Dam at Lake Mendocino. The public was invited. Bill and I attended, as did Fifth Dis­trict Candidate for Supervisor, Dan Hamburg.

Below I report the gist of the meeting.

Local water agencies want to increase the capacity of Lake Mendocino to provide a more dependable source of water, presumably for irrigation. This year, the Corps has raised the level of the lake to the point where some land-based recreation has disappeared, or is unusable.

A significant portion of the lake is now occupied by sediment, thereby decreasing its capacity to hold water. Dredging, however, is not a viable option for reasons of expense, stirring up the mercury buried in the sediment, and huge logistical problems in removing the sediment.

Safety issues must be addressed first. The spillway is undersized, there is some seepage, and the ever-present seismic issue isn’t going away.

Raising the dam remains the most obvious solution, but only after identifying and solving the safety issues. But, studies addressing safety and the feasibility of rais­ing the dam remain low-priority in terms of allocating the very limited Corps budget.

A proposed “solution” to the money and priority issues is to demonstrate unified local and downstream support for completing the studies and raising the dam. This would be done by getting boards of trustees of local water agencies to pass identical resolutions in favor of dam raising. Mike Thompson could then use the resolu­tions to get Congress to pass a special appropriation that would direct the Corps to finish the studies, and raise the dam.

As the meeting was winding down I brought up land-based recreation. A genial Corps employee said that in any environmental impact statement the impacts to land-based recreation would be addressed, as if that solved the problem.

The problem is, however, that land-based recreation will disappear if the dam is raised.

The Board of Supervisors and anyone who hikes, mountain bikes, camps, rides horses, or looks at wild­flowers at Lake Mendocino should speak up in favor of land-based recreation — NOW, before it’s too late. ¥¥

One Comment

  1. September 16, 2010

    Potter Valley people have a little different relationship with Lake Mendocino than other inlanders.
    We see it more often than most, but basically it is water that we are finished with. The watershed for the lake is almost all PV with a little bit from Cold Creek and less than one would expect from the Eel
    Folks from Redwood Valley on south need to be very concerned about the availablity of water from the lake and from the Forks downriver some thought to the dam’s very unlikely failure should lurk.
    I didn’t go to last week’s meeting, but if this article and the UDJ coverage are accurate, then clarity about the issues remains nonexistant.
    I could hear the Corps of Engineer boys that brought us New Orleans 2005 in the voice of Mike Dillabough, who said “There is the strong suspicion that there is something wrong with the dam.” But “It’s been reasonably OK for 50 years.” Then he voiced concerns about overtopping! Even if it may be inadequate, the spillway is 765 feet, 20 feet lower than the dam.
    Then, to make sure this guy is on top of things, he claims the lake is “currently at 757 feet,” when it was 751.
    He states he needs 5 million dollars for a study of raising the dam, including looking into its history. Hmmm, didn’t they build it?
    Last week, a long time ranger at the lake stated she didn’t know why it was higher this year. The Corps resisted raising the level for years.
    There are issues with water levels, including the loss of public use facilities and of lake-edge trees, which are suffuring from the drowning of the their crowns.
    What there isn’t is proof of significant siltation and leakage,
    And while the high water should have made this best year ever for boating, the loss of ramp access has (in my observation) made it one of the the worst.
    I am amazed at how this important local resource is still so poorly understood.
    Raising the dam remains the most expensive and foolish remedy, while common sense seems in short supply.
    Hopefully the “All Boards” will recognize this.

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