Water Shortage or Plumbing Problem?

David Bolling INDEX-TRIBUNE EDITOR, April 27, 2009

Depending on how you define a river, there are well over 100 in California conveying the state’s liquid life through an intricate, arterial maze. Sift through the inventory, river-by-river, and you will find only one discrete system – the Smith, in remote Del Norte County – without a single dam or major diversion.

Sonoma County Water Agency collector well along Russian River near Wholer Bridge. The water agency operates five similar wells on the Russian River. All use the Raney design with laterals extending beneath the river bed in a radial pattern from the main caisson. Each of these wells are capable of producing between 15 and 20 million gallons of water per day. The river water is naturally filtered as it moves through the river bed sediments to the collector wells. Photo taken June 18, 2002 by C.D. Farrar.

California is almost completely plumbed. It has been said that the California Aqueduct – like the Great Wall of China – is one of the planet’s few man-made features visible to the naked eye from outer space. No other society on earth has as much hydrological development as California, and very few have as many rivers at risk, if risk can be defined as significant loss of fisheries, water quality, water quantity, riparian habitat and biological diversity. And as the state grows in population from 37 million today toward a projected 54 million people in 2040, water managers, urban planners, agricultural interests, anglers and environmentalists are all wondering where the water for all those people will come from.

All of which is central to an understanding of why Sonoma, today, is under a mandatory 25 percent-water conservation order until Oct. 2.

Ninety-five percent of the water consumed in Sonoma comes from the Russian River, diverted through six massive subterranean pumps called Rainey Collectors buried up to 60 feet deep in the river’s riparian gravels which serve as a natural filter system. Those pumps, located just up-and-downstream from the Wohler Road bridge near Forestville, can suck some 20 million gallons of water a day through the gravels and into the aqueducts serving 600,000 people.

Infiltration pond next to Russian River and Sonoma County Water Agency’s collector wells near Wholer. The ponds are used to increase the head in sediments overlaying the collector laterals which allows higher rates of pumping. Photo taken June 18, 2002, by C.D. Farrar.

The water reaches the Wohler pumps through several circuitous routes. The Russian River is 110 miles long and it drains a watershed of almost 1,500 square miles, including much of Sonoma and Mendocino counties. Some of that drainage is trapped behind Coyote Dam, on the East Fork of the Russian River, to form Lake Mendocino, southeast of Ukiah. But some of the Russian’s flow is also diverted (some Mendocino activists use the word “stolen”) through a century-old, mile-and-a-half long power plant tunnel in Potter Valley that historically siphoned much of the flow (and most of the salmonid fish) from the East Fork of the Eel River into the headwaters of the Russian’s East Fork.

For a good part of a century, the Potter Valley Project, now owned by PG&E, has been the object of ongoing dispute, fueled in recent years by litigation from Eel River activists who sought to protect that river’s decimated salmon fishery. And for a good part of that century, the diverted Eel River water has been an integral part of the Sonoma County water-supply equation, supplying the Sonoma County Water Agency with an annual 160,000 acre foot bounty of free water.

But because of litigation, and re-licensing scrutiny from the Federal Energy Regulatory Commission, Potter Valley diversions from the Eel River were cut by 15 percent in 2004. Some water watchers argue that the actual amount of the reduced diversion is sometimes closer to 30 percent. Whatever the reality, the result has been less water flowing into Lake Mendocino, leaving less water to release into the lower Russian for both human use and to aid the upstream migration of spawning coho salmon, a fish listed as endangered by the Environmental Protection Agency.

That listing mandates mitigation efforts to save the coho run and mitigation mostly means more water in the fall when the run begins.

More water in the fall means less water in the summer, which leads us closer to the supply feeding Sonoma.

But between Lake Mendocino and those massive Wohler pumps, is a huge supply of stored water sitting behind Warm Springs Dam in a reservoir called Lake Sonoma. There’s enough water in Lake Sonoma to meet all of the Valley’s needs well past the year 2030.

But getting access to it is a whole different problem.