LOS ANGELES, FEB. 15 -- Gov. Pete Wilson (R) responded today to California's worsening five-year drought with a $100 million "battle plan" that would create a water bank to aid the state's driest areas, bolster firefighting resources, drill new wells to preserve fish and wildlife, and provide loans to local districts to develop new water supplies.

Acting on recommendations by a drought-action team that he appointed two weeks ago, Wilson stressed a cooperative approach among federal, state and local agencies instead of state-imposed water rationing. Bill Livingstone, a Wilson spokesman, said most local agencies are "doing everything possible" to combat the drought, including rationing and conservation.

Wilson warned, however, that he is ready to take further steps if local agencies show they are "not capable of coping" with the drought. The State Water Resources Control Board, an independent agency with broad powers, could compel water rationing when it orders new conservation measures Feb. 26.

About half of the $100 million is to be spent on increasing the state's capability to deal with a fire season expected to be the worst in California's history because of the dry conditions. Wilson already had added $50 million for additional firefighters to a state budget carrying a deficit of at least $7 billion.

Perhaps the most important item in Wilson's plan is the proposal to create a water bank that would purchase water from willing sellers and sell it to districts where supplies are short. Much of this water is expected to come from producers of low-value, water-intensive crops such as alfalfa who are finding that their water is worth more than their crops.

Another key proposal would preserve wildlife by drilling new wells and trucking fish downstream from dry areas to lakes and streams in which they can survive.

Water availability in California varies widely among communities and sometimes from farm to farm. Especially hard-hit are cities in the state's central coast region that are largely dependent upon depleted ground-water supplies and nearly empty reservoirs.

Farmers suffering most are those who obtain supplies from the State Water Project, which announced this month that it was canceling agricultural deliveries, and those who rely on the federal Central Valley Project (CVP). The Bureau of Reclamation said Thursday that CVP supplies to California farmers would be cut 75 percent.

In addition to providing water for the neediest agencies, the water bank is designed to accumulate reserves against the possibility of a critical sixth year of drought. Commissioner Dennis Underwood of the Bureau of Reclamation said Thursday that the federal bureau hopes to retain 600,000 acre-feet of water for use if the drought continues into 1992. Each acre-foot is equivalent to 326,000 gallons.

"A drought of this magnitude will change the way we live," Wilson said in announcing his plan at a news conference in Sacramento. "It will cause inconvenience. It will cause anxiety. And it will cause some pain."

Wilson and State Water Resources Director David Kennedy, who headed the drought-action team, nonetheless believe that most California agencies can avert a crisis this year if they pool water supplies. But they are not sanguine about what could happen next year if drought persists.

Agricultural spokesmen responded positively to Wilson's plan, especially to a provision requiring the State Water Project to reevaluate its decision to halt water delivery to farms if rainfall increases.

"From our standpoint, we would view his comments with optimism," said Mary-Ann Warmerdam of the California Farm Bureau.