Lowered Aquifer Will Raise Water Imports and Cost

Too much water has been drawn from Orange County’s vast underground aquifer, which will mean more imported water at greater cost for more than 2 million people, officials said Monday.

“I think we’re looking at higher water rates next year,” said Ron Wildermuth, spokesman for the Orange County Water District, which manages the massive underground basin that serves the northern and central parts of the county. “We’re at a turning point.”

Officials realized this year that population growth coupled with significantly below-average rainfall meant too much water was being pulled from the basin.

To offset that, 23 cities and local water agencies will have to reduce their reliance on local ground water and increase consumption of imported water, which costs more than three times as much. Local water rates would also rise to pay for developing new ways to replenish the ground water. No shortages are expected, however.

Currently, 75% of the drinking water in northern and central Orange County is drawn from the ground water, which costs $127 per acre-foot (an acre-foot is roughly enough to serve two households for a year). The remainder is imported at $450 per acre-foot from Northern California and the Colorado River.

The water basin, which is as deep as two Eiffel Towers and 365 square miles on its surface, holds 10 million to 40 million acre-feet. Up to 1.5 million are usable at any one time.

Wells pull water to the surface and into 23 local water systems. The aquifer is replenished by rain, river water and runoff.

Current policy dictates a target “overdraft” of 200,000 acre-feet, which allows rainwater from two wet years to be absorbed.

But the overdraft has grown to more than double that target.

“This summer, it became obvious,” Wildermuth said. “We’re at a turning point where we need to review the production out of the basin versus our ability to put water back into our basin. We need to invest in new ways to get water into the ground.”

Jerry A. King, president of the Orange County Water District, said in a written statement, “We must back off providing 75% of the [local] supply until we can improve our ability to acquire new water and build facilities to put water into the ground.”

Such a move would be a new, supply-based strategy for the district. The district has operated on a demand-based plan, consistently providing 75% of the local need.

The district will also consider ways to encourage conservation and increase the amount of water replenishing the basin. Those would be in addition to the several programs underway, such as development of a $600-million system to turn sewage into water.

The water district’s staff will begin proposing solutions to the Board of Directors in coming months, but no major decisions are expected until spring. The winter rainfall could affect how deeply cities’ local supplies are cut.

The county agency has repeatedly struggled throughout its 69-year history in balancing withdrawals from the basin with replenishment. It’s an inexact science because drought, population growth and other factors can skew the equation. In the late 1950s, drought pushed the overdraft to its lowest level ever--700,000 acre-feet or 20 feet below sea level.