CalTrans can begin removing vegetation along the proposed route of the Willits bypass after a federal judge denied a request from environmental groups for a preliminary injunction prohibiting such work.

U.S. District Court Jeffrey S. White made his ruling Thursday in San Francisco.

CalTrans officials applauded the ruling. They contended the six-mile, $210 million project will reduce traffic congestion while removing barriers to fish migration on two creeks.

The state's plans will "greatly increase the overall quality of fisheries in these headwaters of the Eel River," said Charlie Fielder, district director for CalTrans.

Spokespersons for the Willits Environmental Center and other groups vowed to press forward with their lawsuit to force CalTrans to consider a scaled-back highway project.

"It will be a shame if irreparable harm is done to salmon habitat before we get our day in court," said Jeff Miller of the Center for Biological Diversity.