Cloud seeding project aims to raise water level at Lopez Lake

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Posted at 11:16 AM, Dec 23, 2022

According to San Luis Obispo County, the Lopez Lake reservoir is currently at 23%, about two-and-a-half years worth of water.

While county officials can't make it rain, they do have a plan in place to make use of the storms we do get to raise the water level at the lake.

“To get any amount of storage that would actually bump the reservoir up to something significant, we would probably need to see about twice as much rainfall as we've gotten so far,” said David Spiegel, San Luis Obispo County Public Works Supervising Engineer.

To increase the amount of water in Lopez Lake, the county approved a cloud seeding program for three more years.

It involves releasing silver iodide into the air.

KSBY Chief Meteorologist Dave Hovde says cloud seeding does work, but you have to have a storm system first.

"Typically what you do is you put condensation nuclei or little particles in the air ahead of a system and then when the system starts to produce a little bit of rainfall or the clouds get heavy, in this case, they would get heavier and just be more likely to drop some rainfall," he explained.

Lopez Lake is used for recreation and provides water to homes and farms.

“We should see about a 10% increase in runoff from it. However, it's directly affected by how many storms we get,” Spiegel said of the cloud seeding program.

“Our reservoirs, our lakes, they're struggling. This can't hurt. We definitely need more rain for them. So in a La Nina year, where typically we expect lower than average rainfall, it can be helpful. In a year that was already going to be wet, probably not a big factor,” Hovde added.

“I believe in 2020 that cloud seeding helped," said Brent Burchett, San Luis Obispo County Farm Bureau Executive Director. "I believe about 400-acre feet were added rain that we otherwise would not have received. So any type of investment in bringing more water — it's not the end all be all, it's not going to cure our drought by any means.”

There must be moisture and cold air for cloud seeding to work, according to Hovde, but if there isn’t any in the air, it doesn’t help.

“Christmas weekend — good example of where cloud seeding wouldn't work. There's no storm system in the area. A good example of when it could actually help us get a little more rain is this upcoming forecast right after Christmas.”

Over the next three years, the county expects to spend about $1 million on cloud seeding.