County Refuses to Revive Cloud-Seeding for Fear of Suits


Despite the looming onset of water rationing because of the drought, Los Angeles County officials won’t resume a cloud-seeding program that produced small but significant amounts of rain on the San Gabriel and San Fernando valleys until it was shelved 13 years ago.

County officials said they worry that renewed cloud-seeding over the San Gabriel Mountains would lead to large numbers of lawsuits if flooding resulted. The potential costs of fighting such suits--such as those that killed the program 13 years ago--far outweigh the benefits of seeding, they said.

Cloud-seeding involves lacing clouds with chemical particles that help raindrops form. By itself, seeding cannot produce rain, but can wring extra precipitation out of existing clouds. Scientists say that the process typically increases rainfall from 5% to 20%.


But many local water retailers argue that the county should resume seeding, saying that it could help replenish badly depleted underground water pools used by many local water utilities.

Water suppliers acknowledge that there have been few rain clouds to seed this winter above the San Gabriels. But they said the county should be ready to take advantage of any clouds that materialize.

“Any rainfall we can get would be a great help. . . . I guess I just don’t understand their reasoning, under the circumstances. I think it’s worth the risk,” said Ed Heck, general manager of the Azusa Valley Water Company, which serves more than 14,000 customers in Azusa, Covina and West Covina.

The County Board of Supervisors voted Jan. 29 to ask state water officials to coordinate cloud-seeding programs elsewhere in California to stimulate rainfall on other areas that could be channeled to the county. They also are discussing joint seeding operations with other agencies. But officials said the county has no plans to revive its program.

The county operated a seeding program on and off for 14 years in the 1960s and 1970s. But it was canceled in February, 1978, after heavy rains caused severe flooding in Big Tujunga Canyon above Sunland-Tujunga. A cloud-seeding had taken place a day before the storm--which killed 11 people and caused $43 million in damage--and dozens of lawsuits were filed against the county.

All of the suits were eventually rejected by the courts, although one filed by a Glendale church was not decided until 1989. But county lawyers say that the costs of defending against a new round of claims that might arise from seeding is too high to risk resuming it.


“It’s just a business decision. . . . If only one or two homes were lost, and the county was found liable, that could be $1 million right there,” said Assistant County Counsel David Kelsey.

Under the old program, 17 rented seeding machines were placed on the upwind side of the San Gabriels. When storm clouds passed over, the machines were turned on, spewing silver iodide crystals, which the wind carried into the clouds. The crystals attract water vapor, providing a center on which raindrops can form.

Runoff following the seedings was captured in the county’s Pacoima, Big Tujunga, San Gabriel and Cogswell reservoirs. From there it was released into “spreading grounds,” where it seeped down to underground water tables. Numerous water agencies pump water from those pools, including the Los Angeles Department of Water and Power.

In an Oct. 24 report, county Public Works Director T.A. Tidemanson said the seeding program boosted annual rainfall over the San Gabriels by 15%. He described the program as “a cost-effective and productive way to increase local water supplies.”

During one 10-year period, he said, the operation yielded an extra 44,500 acre-feet of water, at a cost of $542,000. At current prices, that volume of water would be worth nearly $9 million. An acre-foot is enough water to supply a family of four for one year.

Don Nichols, assistant deputy director of the public works department, said the yield was “not a hell of a lot of water.”

“It’s just that it was pretty cheap to get. The benefit-to-cost ratio was enormous,” he said.

County officials also noted that although a number of public and private water sellers would be helped by a resumption of cloud-seeding, the county government would not directly benefit from it, although it would bear the legal risks.

But water retailers, particularly those in the San Gabriel Valley, said the worsening drought makes it imperative that the cloud-seeding be resumed, despite the legal risks. With the drought depleting local water tables to dangerous levels, any additional water would be welcome, they said.

Andrew Krueger, division manager of the California American Water Co., which serves 20,000 customers in the San Gabriel Valley, said the region’s water table is at its lowest level in 20 years. His firm, he said, recently had to lower one of its pumps in Duarte 40 feet to follow the falling water level.

Renewed cloud-seeding is all the more important, Krueger said, because the giant Metropolitan Water District, which wholesales water to many cities in Los Angeles County, recently informed his company that it will get 30% less water this year to refill underground water pools.

Tidemanson, of the county Public Works Department, said at least five other agencies in California currently do cloud-seeding, although mostly over the Sierra Nevada. One exception is Santa Barbara County, which seeds close to populated areas within the county but has never faced a seeding-related lawsuit.

Tidemanson suggested that his department could work with other agencies, such as the MWD, in a joint seeding project. This would be more feasible than a unilateral county program, he said, because unlike the county, the MWD has the ability to pass on litigation costs to its customers.