The demand for water from the Colorado River is of paramount importance out west and the focus of

some big battles. It's been especially critical for farming and agriculture. And in California's

Imperial Valley, there are growing questions over the use of that resource and whether bigger

changes are needed. Our science correspondent, Miles O'Brien, has this report.

All right, well, let's try one. It was a cool, clear morning in the citrus grove when

Gina Dockstatter sliced open a Mineola orange for me, flooding my taste buds. Oh, that's delicious.

And blowing my mind. Oh, my gosh. It's almost magical when you consider where we are, the middle of a blazing hot, low desert, where Southern California meets northern Mexico, a place that gets unlimited sunshine, but only two to three inches of rain each year. Here we are standing in this lush orchard

in the middle of the desert.

It's amazing.

Welcome to the Imperial Valley,

a half million acres of highly productive,

irrigated farmland, America's winter salad bowl.

If the Imperial Valley didn't exist,

what we would see in produce sections in the winter would be entirely different, wouldn't it?

Entirely different. With salads, with the lettuce, with broccoli. I mean, we just wouldn't have the vegetables. We wouldn't have the fruit that we have now.

About two-thirds of the nation's winter vegetables are grown right here, and it would not happen without water from the Colorado River.

This is Imperial Dam. We're straddling the Colorado River right now.

J.B. Hamby is California's Colorado River Commissioner.

This is one of the final stops on the Colorado River and one of the lowest stretches here in the desert.

Originating all the way up in the rocky mountains as snowfall makes its way here to this liquid gold, which is water that supports our farms and communities all throughout this region.

Hamby is also a director of the Imperial Irrigation District, a powerful and controversial

water agency that controls the single largest entitlement to Colorado River water. About 3 million

...