Nudged along by a lawsuit settlement, the National Park Service has now produced a new management proposal for the river, one that Grand Canyon National Park Superintendent Joe Alston hopes will balance the needs of commercial and private users, as well as at least muffle the long-running argument over the use of motorized boats in the canyon.

"I'm encouraged," said Alston. "Based upon what we hear from a lot of people, I think we have a foundation for a workable plan."

Alston and other Park Service officials will be on hand in Salt Lake City today for a public open house unveiling the draft environmental impact study of the Colorado River Management Plan. The open house is scheduled from 4-8 p.m. at the Miller Campus of Salt Lake Community College in the Karen Gail Miller Conference Center, 9750 S., 300 West in Sandy.

Under the National Park Service's preferred alternative, motorized and nonmotorized use in the Grand Canyon would be split into two six-month periods, with mixed-use occurring from March through October and nonmotorized use from September through February. Currently, the Park Service allows nine months of mixed-use in the canyon.

Annual passenger traffic in the canyon also would increase under the preferred alternative, from the current 22,500 to just over 26,000 - with most of the new numbers being allotted to private permit applications, which have risen steeply in recent years. But Alston says the alternative also calls for fewer daily boat launches and smaller group sizes, which he hopes will lead to a higher-quality experience for river-runners.

"Basically, what we've done is look at the whole hold-launch system," he said. "There are also carrying-capacity issues. We're losing sand in the Grand Canyon and the beaches are getting smaller and smaller. Our bottom line is to not hurt the resources of the park."

But critics say that is exactly what the Park Service is doing in pursuing its preferred choice.

"The river is the only part of the Grand Canyon backcountry that isn't managed as wilderness, and it should be," said Roxane George, spokeswoman for the Grand Canyon chapter of the Sierra Club. "Instead, we get this crazy proposal where [the National Park Service] says they'll manage it as wilderness for six months, and for six months they won't.

"Resource protection should come first," she added. "They've forgotten their priorities."

jbaird@sltrib.com