Board president George Leipzig thinks the Nevada Irrigation District should close recreation at seven high-mountain lakes for a year to stop zebra mussels from invading western Nevada County's drinking water system.

The mussels, native to the Black Sea, hitch a ride on the sides of boats and have become an expensive nuisance since they were first introduced to the U.S. 20 years ago.

A fisherman detected the mollusks in California earlier this year.

On Wednesday, the NID board approved writing letters to Gov. Arnold Schwarzenegger, Assemblyman Rick Keene, R-Chico, and Sen. Sam Aanestad, R-Grass Valley, urging them to consider amending emergency mussel legislation to relax cost and inspection responsibilities for water agencies like NID.

- Laura Brown