Curtailment orders for Russian River in the works as Lake Mendocino storage drops
State regulators will suspend water rights for diverters in the upper and lower Russian River in a desperate, unprecedented effort to preserve a minimal amount of storage in Lake Mendocino, which is falling by as much as 58 million gallons a day.
The rapidly falling lake levels were on course to cross a threshold that would trigger curtailment orders in the upper river under emergency regulations approved in June.
The drought conditions are so dire that staff at the State Water Resources Control Board decided issue emergency orders for the rest of the watershed at the same time.
The pending orders — foreshadowed for months by warnings — nonetheless have created a climate of uncertainty for cities, community water districts and individual property owners throughout the watershed, particularly in the lower reaches, where the scope of its impact was so unclear.
The number of water right holders in the lower river who will be affected was undetermined Monday.
“We’re still fine-tuning those analyses,” said Sam Boland-Brien, a supervising engineer with the State Water Board.
The board hopes to have the orders out to rights holders by Aug. 5, Boland-Brien said. They would take effect the following day.
The Sonoma County Water Agency, which provides water to more than 600,000 people in Sonoma County and northern Marin County will not be affected, district officials said.
However Santa Rosa, Rohnert Park, Petaluma, Windsor, Cotati, Sonoma and Novato and Valley of the Moon Water District, which receive water from Sonoma Water, are still bound by an earlier commitment to reduce their use of river water by 20%.
Up to 2,400 other water rights holders — ranchers, grape growers, community water districts and entire cities and towns such as Cloverdale and Healdsburg — are subject to the emergency action.
More than 900 water rights holders in the upper river were notified in May that they had to stop withdrawing water under threat of substantial fines because of insufficient supplies in Lake Mendocino. Some 660 others with more senior water rights were warned that curtailments were possible this year, after two years of critically low rainfall.
Another 800 water rights holders in the lower reaches of the river, between Healdsburg and Jenner, were subsequently included in the emergency order even though lower river flows are fed by more plentiful supplies from Lake Sonoma.
The suspension of water rights in the upper river is tied to specific trigger points in Lake Mendocino designed to ensure it drops no lower than 20,000 acre feet by Oct. 1.
An acre foot is equal to 325,851 gallons, or about the amount of water needed to flood most of a football field one foot deep.
Under the emergency regulations, a lake level of 26,109 acre feet before Aug. 1 prompts curtailments in the upper river. The lake reached 26,270 on Monday morning and had been losing more than 180 acre feet — more than 58 million gallons — per day.
That could mean Lake Mendocino storage will diminish by more than 2,000 additional acre feet before the curtailments even take effect. That would leave just 4,000 acre feet available to meet minimum stream flows for imperiled fish species and basic human health and safety for most of August and September.
The emergency regulation does not mean people will have no water. Allowances are made for basic human health and safety, meaning diverters can petition the state for waivers entitling each resident to 55 gallons per person per day. That level is only slightly lower than the consumption average already reached in highly water-efficient communities, though it’s fairly drastic for others.
In addition, the state rule allows for other “health and safety needs” including public health threats, basic energy needs, firefighting and prevention of tree die-off where it would contribute to residential fire risk.
People with special circumstances will be able to petition the board and seek accommodation, Boland-Brien said.
But for those unprepared to have their water use restricted, the new order could prove a rude awakening.
Because their initial usage rate was high, Cloverdale’s roughly 9,200 residents would have to substantially increase their water saving efforts even though they are doing fairly well at meeting a mandatory 25% conservation target imposed last spring, City Manager David Kelly said.
“Clearly, we’re going to need a much more significant reduction in consumption in order to meet the curtailment order,” Kelly said.
Calculating the daily per capita use will be a challenge, because some metered water is used in actually treating the water provided to municipal customers. In addition, city legal advisers are still working to determine exactly which water sources are vulnerable to curtailment.