As President Donald Trump prepares to tour wildfire damage in California, he’s zeroing in on one of his frequent targets for criticism: State water policy.

The U.S. president has accused the state of sending too much water to the Pacific Ocean instead of south toward Los Angeles.

It’s one of California’s thorniest problems. The nation’s most populous state is full of sprawling cities, vast farmland, rich ecosystems — and it must decide how to divide scarce water resources among them.