Golden mussels take over water district discussions

MEETING NOTES: 
Agenda packets: 
Rosedale-Rio Bravo Water Storage District: CLICK HERE
Arvin-Edison Water Storage District: CLICK HERE
Westside Water Authority: CLICK HERE
Cawelo Water District CLICK HERE
North Kern Water Storage District: CLICK HERE

The Westside Water Authority, at its March 11 meeting, got an idea of how much it will likely cost to combat the golden mussel invasion – at least $3.8 million. 

And that’s just the start.

The authority is composed of Belridge Water Storage District, Lost Hills Water District, Berrenda Mesa Water District, and Dudley Ridge Water District. Belridge first detected the mussels in its facilities in October 2025. The mollusks have since spread throughout all four districts on Kern County’s western edge.

Members of the authority will separately consider and vote on how much to spend as well as whether to jointly use GreenLeaf Ag 

The authority did not take action on these issues, instead engaging in a lengthy, informal discussion of the problem.

If authority member districts agree to use GreenLeaf Ag, it would employ the chemical EarthTecQZ at lower doses, according to company representative John Bison.

It’s hoped the mussels won’t detect the chemical at lower doses and immediately close up as they do when chemicals are introduced at high levels. If so, Bison said, it could be possible to kill off both the mussels and veligers, larvae, within 14 to 24 days, but no more than 30. 

Even at lower doses, the chemical could potentially affect carp but not game fish, Bison said. He also noted the chemical was OK for drinking water.

Belridge Assistant General Manager Justin Rowe said wildlife agencies haven’t issued any treatment guidelines yet, which could take months. 

Authority board members also questioned why state and federal agencies haven’t begun treating for mussels in the large aqueducts bringing water into the San Joaquin Valley from the Sacramento-San Joaquin Delta, where the mussel infestation originated.

That seemed to be dumping all the costs on local water districts, board members noted.

Rowe said the first round of treatment could be paid for from reserves but regular treatment would likely require additional charges to district landowners.

Rowe said there was talk of Governor Gavin Newsom getting $20 million from Proposition 4 funding to combat invasive mollusks in general.

The authority’s legal counsel, Alex Dominguez, said he feared a lot of that money would go to hiring people to look into the issue rather than directly treating the mussels. 

He said he would prefer the government fund existing eradication/treatment efforts and those programs could then share information as it’s gathered.   

Arvin-Edison

One such program underway is in the Arvin-Edison Water Storage District, which began treatment with SePRO at 12 locations within its system on March 9.

Resource manager Samuel Blue said at Arvin-Edison’s March 10 meeting that they are the first district in North America to begin treatment for golden mussels. 

Though it was believed the mussels don’t spawn in cold weather, Blue said they have found a second generation of golden mussels growing on settling plates the district installed Jan. 3.

On the issue of costs, board members said more focus should be placed on incoming ships.

“We need to continue to do something legislatively to be able to continue to get those boats cleaned and not bring in any more (golden mussels),” said board vice president Catalina Martinez. 

Jeevan Muhar, engineer manager of Arvin-Edison, advocated the state declare the mussels a statewide emergency in order to free up federal funding.

Cawelo, North Kern, Rosedale-Rio Bravo

At their March 12 and 17 meetings, respectively, Cawelo Water District and North Kern Water Storage District discussed using the EarthTecQZ small-dose strategy. 

The districts, which haven’t found mussels in their systems yet, have not settled on a pest treatment company but agreed they would share the costs.

“Now that ( golden mussels) are in the (statewide) system they’re there, and it is probably going to be pretty impossible to completely eliminate them,” said North Kern General Manager Dave Hampton

At its March 10 meeting, Rosedale Rio-Bravo Water Storage District also considered installing settling plates made of materials that attract the mussels to help make it easier to detect them. 

The district did not discuss any potential treatments it could implement before detection.