Californian groups clash over geothermal water use

Electricity and water came together with a bang this week, as policymakers in a Californian county controversially decided to let an energy company pump water from a local wetland.

The Inyo County Planning Commission, California, granted a permit to the Coso Operating Company, a local geothermal plant operator, to pump water from the Rose Valley acquifer. The water will be sent through a pipeline to the plant, to help improve its efficiency.

The deal has angered a local hunting club, which relies on the water to maintain the wetlands, according to reports in the Californian press. An alliance of local environmentalists has formed with the hunting club to appeal the decision to the Inyo County Board of Supervisors.

The impact analysis for the project lists a potentially significant impact on hydrology in the region, but adds that there is little available data to make an accurate assessment. The wells are replenished by precipitation and run-off from the Sierra mountain range at a rate of roughly 5,000 acre feet a year.

Bob Harrington, director of the Water Department, said: "That looked like the project was proposing to take virtually all the water that enters the valley each year, and by our own analysis, that would have a significant impact on Little Lake, because that's where a substantial proportion of the groundwater is currently discharging. It's a question of a water balance - sort of like a bank account."

The final permit reduced the water allowed under the pumping permit from Coso's original application to 3,000 acre feet a year, he said. However, that pumping rate could be increased to 4,800 acre feet per year if the monitoring wells showed that there was no harm being done, he said.

If levels in monitoring wells fall below triggers specified by his department, he would be able to stop the pumping altogether, he warned. " Ultimately they are taking a gamble, because they don't know how much water they are going to get," he said. "And we have been pretty explicit with them that they should have their eyes wide open. They may be taking a big risk in investing that kind of money in this pipeline."

Coso needs the water because the 22-year-old geothermal plant is operating below peak efficiency. "When we first developed the site in 1987, there was an understanding that some additional supplemental water may be required. It is common in industry practice because there is some loss of geothermal fluid through evaporation," said Joseph Greco, senior vice president of Terra-Gen Power, which owns Coso. He argued that the hydrology model was conservative and that water supply would not be a problem.

Randall Gentry, director of the South Eastern Water Resources Institute at the University of Tennessee, said that disputes over water in the drought stricken southwestern US could escalate in the coming years, pivoting around what he called the "energy water nexus".

"Particularly in times of extreme drought, for lack of any other resource, groundwater resources can be longer term storage reservoirs, and so people will be looking to those areas that have prolific stores of water as a resource for more than just drinking water - for industrial or energy purposes as well," he warned.

Michael Campana, director of the Institute for Water and Watersheds at Oregon State University, has lived most of his life in the southwest of the country. He warned of the need for strict governance in any water-based agreements between municipalities and private companies. "There have to be real clear ground rules and expectations about what the private companies can and can't do, and there also needs to be oversight," he warned. "You just can't turn over everything lock stock and barrel to the company and let them walk away, and not keep your eye on it."