You hear this every time there’s a drought or deluge in California: “Why haven’t they built more dams?” Truth is, they’ve built a bunch. And they’re about done with it. Tally them up. There are more than 1,400 dams in the state. At least 1,000 are major and 55 can hold 100,000 acre-feet or more of water. One acre-foot is enough to supply two average households for a year. There are 36 reservoirs that can contain at least 200,000 acre-feet. Eleven can hold 1 million or more.