After millions of dollars of flood damage and mass evacuations this year, California is grappling with how to update its aging flood infrastructure. Some say a natural approach might be part of the answer. All the water that poured down spillways at the Oroville Dam in northern California did a lot of damage to the area — and for miles down the river. “It looks like a bomb’s gone off,” says John Carlon of River Partners, a nonprofit that does river restoration. “That’s what it looks like.”