And, about the comment about water shortage-- doesnt a significant portion of California's water flow through Nevada from the Colorado river? If so, Nevada is not lacking in water as much as in political power.
As far as the distribution of the Colorado River Systems water goes, that's a mess that dates back to 1922.
Family business growing up (started by grandfather/father above): drilling water wells. So, ya know, I've got a layman's understanding.
In the West, water rights are property rights. There are nearly 100 year old agreements on the split of water taken from the Colorado river.
Look up Arizona v. California.
In summary, as long as at least 7,500,000 acre feet of water is available from the Colorado River, California is allocated 4,400,000 acre·ft; Nevada, 300,000 acre·ft; and Arizona, the remainder. If more water is available, California is entitled to 50% of the water from the Colorado River, Arizona to 46%, and Nevada to 4%. If less water is available, the Secretary of the Interior must allocate the water according to various formulas (which were the subjects of the court cases) to ensure that each state receives a specified amount, with California receiving an absolute fixed maximum of 4,400,000 acre feet per year (547 U.S. 157).