Details on why they're considering that strategy will be part of County Administrative Officer Susan Thompson's update to the board of supervisors on the exotic species' effect on the popular reservoir - and how government officials are trying to fix the problem. Thompson's presentation is on the agenda for the supervisors' meeting at 9:30 a.m. Tuesday at the County Administration Building.

The mussels' discovery at San Justo in January 2008 was the first known presence in California of the species - which can clog pipes and ravage water ecosystems, and has caused billions of dollars in damage to other, larger bodies of water such as the Great Lakes.

In San Benito County and throughout the region, connected by the very water system to which San Justo connects, officials have taken steps to assure the mussel hasn't spread elsewhere and, ultimately, to rid the species altogether from the local reservoir. Thompson's update also will touch on local impacts from the discovery and the reservoir's subsequent closing to recreational users.

But the focus should be the eradication method, toward which officials with the U.S. Bureau of Reclamation, which owns the site, and local agencies are leaning.

Thompson's PowerPoint presentation will note how sodium potash slurry would rid the mussels at levels unharmful to other wildlife. Different methods, the presentation points out, "may not be suitable due to possible impacts" on wildlife and agriculture.

The Santa Clara County Parks and Recreation Department created an inspection system to keep Zebra and Quagga mussels out of the reservoir because of Santa Clara Valley Water District concerns.

Eradication could take place in late 2008 or early 2009, according to the report.