. >> reporter: university of colorado san diego professor steve erie is an expert on water use.iculture has been hit badly, that may be in portions of the central valley it's not the case on the colorado, with the impeeria valley. >> this is where he's talking about. the western part of the sinoran desert. near the border. and not far from the colorado river. it gets on average. three inches of rain annually and is in the 15th year of a drought. it's pretty much the last place you expect to grow crops like cotton and wheat. that is exactly what is happening. >> we don't grow. but farmers grow in the valley. >> the family has been farming for 100 years. >> how do you grow grass in the middle of the desert. >> well, you just add water. >> and do they ever. more than 880 billion gallons of colorado river water is used every year by this farming community of less than 200,000 people. the entire rest of southern california uses less than half of that. >> you wouldn't know that this is a waste land. every place i look there is water. there's water all the way down to my right, and wat