SteveO is right. Raising the dam heights will only allow collecting and retaining water on above average years to carry into low rainfall years. But how often does Shasta or any of the other large reservoirs in the state reach capacity? Every time they do and water goes over the spillway it's a big newsworthy deal. California's problem isn't just capacity. It's the number of people using the water. California has to figure out how to reuse and find new sources of water or stop growing.