This story originally ran in Steamboat Living magazine.

Some people float Yampa Canyon for the weeds instead of the whitewater.

That's especially true for a group of Steamboat locals who, for the past 20 years, have plied the 72-mile canyon through Dinosaur National Monument to help rid the stretch of tamarisk, an invasive species crowding out native flora. In June, nearly 20 locals joined a flotilla to help eradicate the shrub, bringing to an end the program's 20-year history.

The monument's Weed Warrior program was started by park botanist Tamara Naumann in 1997. When local river runner Jim Linville floated by and saw a ranger pulling up the trees, he asked how he could help. "He said to send in a letter on official letterhead," says Linville's wife, Joan Donham. "So we went to the local nonprofit, Friends of the Yampa."

Friends of the Yampa has joined the effort ever since, its participants floating the canyon with saws, tri-pods, axes an shovels in tow to pitch in against the invasive species.

"The original folks that got involved were longtime river runners who wanted to help do something about the park's tamarisk issues," says longtime participant Hugh Newton.  "It's a lot of work but a great way to get down the river."

The group has largely focused on mechanical removal of the shrub, using a specially designed tripod to yank its roots out of the ground. Over the years, the group's also developed additional tools for the weed-pulling purpose, starting at overrun campsites and progressing to popular lunch spots and study sites.

The monument was also one of the first parks in the country to use bio control, involving beetles, to help the effort.

"Both efforts – human and beetle — are part of a larger integrated program," Naumann says. "People work better in places where we want to physically remove the plants, which is slow and labor intensive; the beetles are used in more obscure spots to reduce tamarisk's dominance. Both efforts have been successful and have made a big difference."

Alas, it all comes to a close this season; Naumann retires with the program this year. In its two-decade run, she adds, the program has seen 6,612 volunteers help with the effort.

None of these arm-scratched volunteers has been more dedicated than the Steamboat crew, which most recently suffered through 100-degree heat and marauding mosquitos to help expose the Mitten Park Spring below Echo Park.

"I feel privileged to have encountered a group of people who spend their vacation time working their tails off in the heat of the desert while combatting mosquitos," says Naumann. "Steamboat folks are a hearty crowd … the last couple of years have been a little rough."