If there is such a thing as a virtual towel, you might want to bring it to the new IMAX release "Grand Canyon Adventure 3D: River at Risk...

If there is such a thing as a virtual towel, you might want to bring it to the new IMAX release “Grand Canyon Adventure 3D: River at Risk.”

“Grand Canyon” is such fun to watch with its superb, 3D quality that it’s impossible not to be more caught up, albeit temporarily, in the illusion of getting splashed than in the unsettling realities of the environmental crisis it describes.

The film concerns a serious subject: our growing, global water shortage. Filmmaker Greg MacGillivray uses the visible decline of the once-mighty Colorado River, which snakes through the Grand Canyon at a much lower level than it once did due to severe exploitation, as a case study in a worldwide phenomenon.

But the river is hardly gone yet. With its immense image projected onto one of the six-story-high IMAX screens at the Pacific Science Center, “Grand Canyon” gives one the feeling of actually sitting on the banks of the Colorado, or bouncing along its wild rapids on a raft. The movie is all the more rewarding for taking viewers through a spectacular experience with the likes of Robert F. Kennedy Jr., a noted expert on restoring sick rivers, and author-anthropologist Wade Davis (“One River”).

Both men bring along adolescent daughters (Kick Kennedy and Tara Davis) to share in a spirited assessment of the Colorado’s condition. The journey requires harrowing time on rafts, but along the way, ample evidence builds that the river is in truly bad shape. That’s because 25 million people depend on it as a source of water and power, including Las Vegas.

Producer-director MacGillivray does a great job of alternating fascinating details about the region with the larger story of Earth’s diminishing water supply. Narration by Robert Redford and a soundtrack by the Dave Matthews Band also help us swallow the bitter pill of this looming ecological disaster.

Tom Keogh: tomwkeogh@yahoo.com