New Dams Proposed in California

by Steven L. Evans
Thursday, February 1, 2007

Water pundits claim that the era of big dam building is over in the United States, but someone forgot to tell California Governor Arnold Schwarzenegger. Schwarzenegger is proposing to invest $4 billion in general obligation and revenue bonds to build the Sites Reservoir in the Sacramento Valley and the Temperance Flat Dam on the San Joaquin River Gorge. His proposal promises to renew an ongoing battle between dam proponents and those who would like to see the state invest more wisely in water efficiency and recycling.

Governor Schwarzenegger says he believes that the new dams are needed to meet the needs of California’s growing population, which is expected to increase by 23% in the next two decades. The problem with this prediction is that it assumes that California will continue to use the same amount of water per capita as it does today.

The state’s own blueprint for water, the 2005 California Water Plan, shows that water use has declined and will continue to decline as more investments are made in water efficient technologies. California has already cut per capita use of water in half in the last 40 years. In addition, the Water Plan proves that more reliable amounts of water can be provided by urban and agriculture use efficiency, recycling, and groundwater management than from building new dams.

Additional investments in water use efficiency and recycling can produce far more water through conservation than similar investments in new dams. In fact, one dollar invested in urban water use efficiency produces four times more water than five dollars wasted on costly and destructive new dams. Although some regions such as Southern California do a relatively good job in using water efficiently, more can be done. And some regions such as the rapidly suburbanizing Central Valley have invested relatively little in water efficiency. In fact, many of the major cities in the Central Valley – including the state capitol of Sacramento – still do not meter or charge for water by volume, which is a basic first step to prevent water waste.

Governor Schwarzenegger also claims that California will need to build more dams in response to global warming. Scientists predict that global warming will indeed increase rain and reduce mountain snow pack, where much of the state’s surface water is naturally stored. But many of these same scientists believe that California’s already robust system of more than 1,200 large dams is sufficient to handle increased precipitation caused by global warming. One University of California hydrologist pointed out in a recent newspaper article that most of California’s major rivers have been dammed already and the dams are much bigger than are now needed. He believes that the existing dam system will handle snow pack losses from global warming.

Recent studies indicate that building new large reservoirs will actually increase the greenhouse gases that cause global warming. Not only do years of construction to build large dams create emissions, but reservoirs themselves create emissions from organic material decaying in the water. One study found that Shasta Reservoir – the state’s largest storage facility – released 224 tons of carbon dioxide per day, an amount equal to 14,500 automobiles driven 40 miles a day.

Evaporation from California’s major reservoirs is also a problem. In fact, the dams proposed by Governor Schwarzenegger would produce roughly the same amount of water – about 500,000 acre feet – as is lost annually via evaporation from all of the state’s current reservoirs. Building two more large reservoirs will only increase evaporative loss.

In addition to the larger policy issues associated with renewing the bad old days of building big dams, the projects identified by the governor are of dubious merit.

The Temperance Flat Dam would drown up to 7,000 acres of public land in the San Joaquin River Gorge that is now managed for outdoor recreation, wildlife habitat, public education, and traditional Native American cultural uses. The dam would drown at least two existing hydroelectric power plants. Its reservoir will seldom fill, because most of the San Joaquin River’s water is already captured behind existing dams. The San Joaquin River has been so thoroughly dammed and diverted that it runs dry downstream of Fresno in most years.

The Sites Offstream Storage Reservoir in the Sacramento Valley would be filled by water diverted from the Sacramento River. It would use at least one existing diversion dam that currently impedes the migration of 70% of the threatened spring run Chinook salmon that spawn upstream. So much water could be taken from the Sacramento River to fill Sites that the river’s riparian ecosystem could be degraded and critical habitat for dozens of threatened and endangered species lost. The reservoir itself would drown 14,000 acres of grassland, oak woodland, and vernal pool habitat, and possibly hundreds of Native American and historical sites. The project would also be an energy hog, requiring electricity to pump water into the reservoir, thus adding to the project’s greenhouse gas emissions.

More than 60 conservation, recreation, and Native American cultural organizations and businesses recently signed a letter urging Governor Schwarzenegger to “terminate” his plan to build new dams in California and to instead invest wisely in water use efficiency and recycling – a move that will produce more water and cause less environmental harm that building costly new dams.