Local water officials continue to evaluate ways to eradicate
invasive zebra mussels from the San Justo Reservoir on Union Road
and now expect that the popular fishing and boating spot will
likely not reopen until 2011.
Already having been closed since the fingernail-sized mussels
were discovered there in January 2008, San Justo will not be opened
to the public until all zebra mussels are gone from the reservoir,
which stores and distributes water for agricultural use. The
reservoir gates have been locked to make sure boaters or fishermen
do not inadvertently transport the mussels to other waterways.
Local water officials continue to evaluate ways to eradicate invasive zebra mussels from the San Justo Reservoir on Union Road and now expect that the popular fishing and boating spot will likely not reopen until 2011.
Already having been closed since the fingernail-sized mussels were discovered there in January 2008, San Justo will not be opened to the public until all zebra mussels are gone from the reservoir, which stores and distributes water for agricultural use. The reservoir gates have been locked to make sure boaters or fishermen do not inadvertently transport the mussels to other waterways.
“We’re continuing to move forward with the evaluation and moving to a preliminary design of what the control mechanism for the mussels would be,” said San Benito County Water District Manager Jeff Cattaneo.
Zebra mussels originated in Europe were found in the eastern United States in the 1980s.
The freshwater creatures are harmful to water systems because they produce toxins that kill native organisms and also reproduce so quickly and in such great numbers that they can clog drinking water or agricultural irrigation delivery systems.
At a recent water district board meeting, it was reported that the Bureau of Reclamation is finalizing its evaluation of the site, particularly about whether the best course of action would be to draw down the reservoir and try to kill the mussels with potash, or potassium chloride, a type of salt that disrupts mussels’ ability to filter feed.
Officials believe the potash would cause the mussels to open up, at which time they could be killed with chlorine or left to die on their own.
“If they can get a 100 percent kill rate from the desiccation process with the ones that were exposed, then we’d move forward with that plan,” Cattaneo said. “If it looks like they would not all be killed, we’ll have to plan something else.”
The Bureau of Reclamation studies on the reservoir should be completed within the next couple of weeks, Cattaneo said, at which time the water district will begin refilling San Justo with water that will be stored for agricultural use in the summer.
“After they evaluate the results, there’s a whole permitting process we’ll have to go through,” he said. “The earliest we could re-open the reservoir would be next winter, though the way the schedule’s going, we’re looking at 2011.
