Rain Making


Lake Nacimiento

The Reservoir Operations Committee of the Monterey County Water Resources Agency Board meets today to discuss options for dealing with the shrinking San Antonio and Nacimiento reservoirs.

Although rain will likely be falling as the meeting convenes, the situation at the reservoirs is dire. Although it’s the middle of the rainy season, Lake San Antonio is at only 5% of capacity, less than the amount considered to be its “minimum pool,” and shrinking further every day. Lake Nacimiento is at 22% capacity and dropping even faster.

Without rain, and a lot of it, no set of options is going to solve the problem. Agriculture won’t be getting the water it needs, salt water intrusion problems will grow worse, tourism at the lakes will collapse and, with nowhere to swim, the Wildflower Triathlon may have to be turned into a mud run. So it’s no surprise that one item on today’s agenda is a discussion of cloud seeding.

As cloud seeding and other forms of rainmaking are generally associated with itinerant hucksters in top hats firing cannons into the air for crowds of rube farmers, few realize just how common the practice has actually become. Although many, including the National Academy of Sciences, still consider the effectiveness of cloud seeding unproven, something like a dozen cloud seeding projects are currently ongoing in California. Most are carried out by PG&E and are aimed at enhancing the Sierra snow pack in order to boost hydroelectric production. This makes sense since, as long as they receive PUC approval, the programs don’t need to be effective in order to make PG&E money.

The history of rainmaking in California really began in 1915, when the San Diego city council agreed to pay a sewing machine salesman and rainmaker named Charles Hatfield $10,000 if he could produce enough rain to fill a newly constructed reservoir. Soon after he began releasing his secret formula of chemicals into the air, a month long series of “atmospheric river” type storms began. Massive flooding, a collapsed dam and multiple deaths resulted, for which Hatfield was blamed. Although he had more than lived up to his side of the agreement, the city refused to pay his fee.

Modern rainmaking, which generally involves seeding clouds with silver iodide vapor, dry ice, or both, in order to provide nuclei for the formation of ice crystals, got going in the 1940s. Los Angeles experimented with cloud seeding in the 1970s, but stopped after being sued over flooding in 1978.

The Monterey Water Resources Agency first joined the game in 1990, and continued seeding clouds off the Big Sur coast until 1995, when there were complaints that seeding might have contributed to the major flooding on the Carmel and Salinas rivers. The Agency ran into trouble again when it proposed seeding in 2009. With freshly burned slopes acutely vulnerable to landslides and debris flows, Big Sur residents were not eager to have their rainfall enhanced and the idea was quickly discarded.

So what can the Agency expect if it decides to move forward with a rainmaking program now?

Looking at the issues besetting other rainmaking projects around the state and world, we’re guessing they’ll need to prepare themselves to explain why they think spending a few hundred thousand on cloud seeding will produce more water than spending the same money on conservation; why the program won’t be “stealing” rain by wringing water out of clouds that might later have dropped it somewhere else; why they shouldn’t be liable for flood damage that occurs while they’re seeding; why silver iodide won’t “pollute” the water supply; how they’re not part of a massive “chemtrail” conspiracy to alter the climate and poison the population; etc.

It should be an interesting public process.

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