[jeffbee]

Sure, but the denominator for flooded irrigation is huge, so the efficiency is high. That's why flooding is a superficial and not substantial problem. The plant transpires water at a certain rate and a certain density per ground area. That rate isn't influenced by whether the field is flooded or drip-irrigated. By the way flooding also provides wildlife habitat.

Anyway I'm just tired of the meme about growing rice in a desert. California rice country isn't a desert, it exists in places that were annually flooded before flood control engineering, and should still get flooded for various reasons. It is not a waste of water.