Needed: Blueprint for Spill Prevention : Questions Remain About Preventing Further Damage at Prado Dam Reservoir

There are many questions remaining about an oil spill in January in the Prado Dam reservoir. How to get 13 aging oil wells out of the reservoir is highest on the list. This is important both to preserve water for Orange County’s underground aquifers and to protect acreage where the endangered least Bell’s vireo nests in the spring.

Water officials say there was a spill when winter rains caused water levels to rise behind the dam and inundate the wells. Who’s to blame is in dispute, but Orange County water officials have accused oil well owner Prado Petroleum Co. of Santa Ana of failing to properly clean and secure sumps, or cellars, near four wells.

Water officials said that when water levels dropped, about 80 barrels of oil spread over about 900 acres. Prado Petroleum says only about 20 barrels spilled, damaging about 100 acres. Whatever the numbers, about 40 birds died, and cleanup and containment cost nearly $200,000.

And that’s only the beginning. Improvements to the oil wells--needed to prevent another spill--could cost as much as $12 million. Nor is there the option to do nothing; replacing the 3 billion gallons of water that could otherwise be directed to Orange County’s aquifers could cost water customers $2 million a year.

In the past, reservoir water was lost to Orange County when it was channeled directly to the ocean to prevent flooding on the Santa Ana River flood plain. Now the Orange County Water District has an agreement with the Army Corps of Engineers to capture runoff from the dam, which is located in Riverside County near the Orange County border.

Plans are to release the runoff slowly in the spring and feed it into the district’s aquifers. These gigantic natural storage tanks, which serve about 2 million customers, have helped Orange County to weather the state’s six-year drought as well as it has. The recapturing plan means that more land behind the dam must be inundated, and that affects the habitat of the Bell’s vireo, which is protected under the federal Endangered Species Act, and other wildlife. To compensate for this, the water district is creating more habitat. But the presence of the oil wells in the reservoir complicates things because of the risk of contamination.

A way must be found to prevent another damaging spill and, unfortunately, the overriding public interest and high cost of protecting against contamination may argue eventually for closing the wells. Otherwise, billions of gallons of valuable water will be, well, just water over the dam.