Cranking hard, Dennis Porter humps his mountain bike over a tree root, splashes through a puddle and tears across a patch of deep, sandy silt along the Minnesota River bottom in Bloomington.

Porter is among hundreds of mountain bikers whose knobby tires have carved out a series of rugged trails beside the river. The 12-mile stretch between the Old Cedar Avenue Bridge and the Bloomington Ferry Bridge has become one of the most popular mountain-biking venues in the Twin Cities.

But the mountain bikers soon will have to share their leafy paradise, according to state officials who have long viewed this stretch of river land as a key piece of a growing state and regional trail system. The resulting debate over public land use is similar to those that have occurred across the country between advocates of different forms of recreation.

In the last legislative session, state lawmakers earmarked about $2.1 million to build a new trail through the area, which includes the Minnesota Valley National Wildlife Refuge. The same qualities that appeal to the mountain bikers should be made accessible to everyone, officials said.

"You're just excluding the overwhelming majority of users if you say that's all we can have," said state Rep. Ann Lenczewski, DFL-Bloomington, who represents the area and secured the funding for the trail. "This is a huge river valley, and it's my personal view that we hold it as a community, the larger public. And we all get to use it."

The Bloomington trail is a linchpin of the larger system, said Brett Feldman, executive director of the Parks & Trails Council of Minnesota, a group that raises money privately to buy land for public parks.

"This trail will eventually go to Fort Snelling," Feldman said. "And that connects to the Hiawatha Trail, and that connects to the Midtown Greenway, and that connects to the western suburbs. This particular trail is really the spine that connects everything together."

Mountain bikers have been riding along the river bottom for more than 20 years, said Porter, a lifelong Bloomington resident and a founding member of Minnesota Off Road Cyclists, a group with more than 900 members.

Riders prize it for the challenging terrain and its sense of remoteness. "People like the ability to feel like they're miles from anywhere," he said.

Bikers have invested countless hours in maintaining the trail: removing downed trees, trimming branches, bridging small ravines. In a recent ride along the trail, Porter said he knows cyclists who have actually moved to Bloomington to be closer to the river trail.

The area regularly floods, Porter said, and any paved or even gravel trail would require frequent and expensive maintenance. But his main objection is to changing the natural character of the trail when there are already so many miles of paved and improved trails in Minnesota.

Seeking broad use

That's just the point, say backers of the improved trail. Minnesota has been pursuing a long-range trail plan for more than 25 years. And the Minnesota River segment has always been part of the plan.

"This corridor was established decades ago as a state trail," said Luke Skinner, deputy director for the Division of Parks and Trails at the state Department of Natural Resources. "I'm a Bloomington resident; I'm a mountain biker myself. I've ridden down there, and I appreciate the passion they have for protecting the trails they've developed over the years.

"I don't think there's any intent to make this just a paved trail and eliminate everything else," Skinner said. "The department is really interested in meeting the needs of a variety of interest groups, including the mountain bikers." Skinner said planning for the trail will take place over the next year, with completion likely within four years.

Lenczewski said the bikers are jumping to conclusions, and there's no reason the trail system can't accommodate all users. The improved surface doesn't have to be asphalt; it could be crushed limestone. And the new trail doesn't have to run along the river bottom, she said; it could be placed higher on the bluff, leaving the bikers' natural trail in place below.

"We have to make it work for everybody," she said. "All these people who have supported it — they wouldn't have supported it if they didn't think they could use it.

"You can't stop it. The money has been given to complete the trail," Lenczewski said. "And if we're going to invest this kind of money, shouldn't it work for people and their kids, and their grandparents, and also the people who want a rugged experience? I will be personally disappointed if we can't make it work for everybody."

John Reinan • 612-673-7402