* "Watershed" documentary aims to stoke social awareness

* Colorado River exemplifies water issues worldwide

* Redford, son focus on people as solution to problem

By Robert Muir

WASHINGTON, March 26 (Reuters) - Actor and director Robert Redford, a longtime environmental activist, has teamed with his son to film a documentary about the Colorado River system, which conservationists believe is endangered by decades of development and global warming.

Redford, 76, who lives in Utah, traveled to Washington, D.C. along with Jamie Redford, a Northern California resident, to discuss the urgency of the message in their film, "Watershed," featured recently at the D.C. Environmental Film Festival.

Both father and son have been tireless vocal advocates for conservation, particularly in the western United States. Their documentary, produced by Jamie Redford and narrated by his father, draws attention to the enormous and, they say, unsustainable demands on the Colorado River system that provides much of the American west with water.

"The watershed issue is something that's happening all over the world, where the need for water is greater than the amount of water to provide for it," Robert Redford told Reuters.

"I think we're picking the Colorado River as an example of what's going on with watersheds all over the world and trying to focus on that and draw attention to it."

The river flows from the Rocky Mountains 1,450 miles (2,333 km) to the Gulf of California. But, as the Redfords' film points out, the water rarely makes it that far because of the multiple demands of agriculture, industry and communities upstream.

The film opens with an explanation of the history of the Colorado River system's development, starting with the Colorado River Compact of 1922, which provided for the equitable division and apportionment of the water among seven states in the U.S. and two in Mexico.

But "Watershed" holds that the compact, 90 years later, has transformed one of the world's wildest rivers to the point where it will soon be unable to provide sufficient water for the populations dependent upon it.

"With population in the region expected to reach 50 million by 2050, temperatures rising and precipitation patterns becoming more erratic, demand will outpace supply unless we embrace a new water ethic" Redford says in the film.

A star of hits including "Butch Cassidy and the Sundance Kid", "All the President's Men", "The Sting" and the Oscar-winning director of "Ordinary People," Redford hopes "Watershed" serves as a warning.

"There's a new water reality that people have to be aware of, and I think looking at the Colorado River as an example is what this film's about.

"I think it's using art as a tool for social awareness, you know, making a film about an issue and then getting it out to as many people as possible increases awareness. Maybe increased awareness will help solve our problem," he said.

The film illustrates the various demands on the Colorado River through the eyes of the people who live on it, from a fly-fishing instructor near the river's source to farmers and families living downstream. Jamie Redford said that by enlisting real people in the project, the issue was more likely to resonate with audiences.

"It was pretty clear from our point of view that what we wanted to do was specifically focus on people, and we wanted to take a positive look at what is a challenging situation," he said.

"So, in that regard, we found characters up and down the river from the headwaters all the way out to the Colorado delta in Mexico that are fighting to make a difference and are making a difference and setting an example of what you can do."

As a California native and long-time resident of Utah, Jamie's father said he has watched the gradual depletion of the Colorado for 50 years and that the issue is too important to ignore any longer.

"You've got 30 million people dependent on that water source, and a lot of that dependency is urban renewal, booming metropolitan cities. You've got drinking, you've got sanitation and you've got electrical generation. You pull that off the river," said Redford. "Plus, the agricultural water rights that the farmers and ranchers have. You've got a depletion that has to be looked at."

An early supporter of President Obama, Redford said he is disappointed by the administration and Congress's progress on future fuel sources, noting that non-sustainable, carbon-based fuels are a major contributing factor to global warming and the problems facing those who depend on the Colorado River.

But no one in government, Redford said, is courageous enough to make decisions that could prevent worsening of the situation.

"The future is about young people," he said. "Young people coming on today, like Jamie my son, his son, other generations coming, what are we thinking about them?

"I think we have such a tendency to think short, short term, and therefore apply short term solutions to longer term problems. We're just not going to get there unless that changes." (Editing By Chris Michaud and Bob Tourtellotte)