Sam Brasch/CPR News Visitors soak in the evening at Conundrum Hot Springs, outside of Aspen, Colo.

In the thick of summer, a certain smell overpowered the wildflowers at the trailhead for Conundrum Hot Springs. Armed with gloves, volunteers checked under bushes and scanned nearby campsites for the source.

You can probably guess where this is going. Over the course of a couple hours, they loaded an entire trash bag with human waste.

The problem continues up the 8.5-mile trail. The natural alpine pools outside of Aspen can draw more than 300 visitors a night. Many stay multiple evenings and have to answer nature’s call.

“To be quite frank, that’s a lot of poop,” said Katy Nelson, wilderness and trails program manager for the Aspen-Sopris Ranger District of the White River National Forest.

As visitation spikes, the U.S. Forest Service is taking on the turds. It already asks hikers to pack it out, but the practice could become mandatory starting next summer — part of a proposed management plan for the Maroon Bells-Snowmass Wilderness.

Sam Brasch/CPR News Ranger Katy Nelson carries her trusted shovel, known as "shovie," on most patrols into the backcountry.

If approved, the Forest Service plan would implement a paid overnight permit system for the Conundrum area. It would also require visitors to bring bags to carry their defecation out of the wilderness.

It could be tricky to get hikers on board.

Leave No Trace, a group that sets guidelines to minimize impacts, recommends hikers bury backcountry bowel movements in most areas. Protocol is to dig a “cat hole” away from trails and water sources. Covering the waste hides it from wildlife and spurs decomposition.

Stacked challenges make that practice ineffective at the Conundrum Hot Springs, Nelson said. The narrow drainage provides little escape from water. And because it’s so popular, an open spot to dig can be hard to find.

That means rangers often have to teach people a new process for backcountry bowel movements.

Earlier this summer, the Forest Service brought in some backup. They partnered with educators from Leave No Trace to clean up the area and spread word about wag bags, the proposed solution.

Sam Brasch/CPR News Ranger Katy Nelson checks permits and talks hikers through their backcountry bowel plans.

“Wag bag” is a catch-all term for products that store human waste for safe disposal. At Conundrum, the bag of choice is the Restop 2. It’s a ziplock sack made of silver mylar with an inner plastic liner. The label promises users they can go “anywhere, anytime.” They’re available for free at the trailhead, but each one costs the Forest Service about $2.40.

On the hike up to the springs, Donielle Stevens, a traveling trainer with Leave No Trace, stopped a pair of women just out of college to ask about their wag bag situation.

Neither had brought one.

Stevens handed some out and explained the procedure: Open the bag on the ground, then weigh it down with rocks to protect against the wind. Business goes inside. Next, press out all the air before it’s sealed. This is important. Skip that step, and the bag could expand and explode in the heat.

“We feel so equipped now!” said hiker Amelia Pellegrini.

Farther down the train, Pellegrini emerged from the woods, victorious, with a used wag bag. “It was so cool. It just changed my hiking life,” she said. “Now, I just need to figure out what to do with it, though.”

In the end, she clipped it to the outside of her pack. If all went according to the Forest Service’s plan, she hiked it out and drove it to a trash can.

Other public lands require portable toilet systems. River rafters in Dinosaur National Park must bring a sturdy metal or plastic latrine. Climbers of California’s Mount Whitney or Washington’s Mount Rainier have to descend with their poop. In 2013, Canyonlands National Park in Utah set the same rule for those hiking into its popular Needles Districts.

Unlike those places though, Conundrum has a well-earned party reputation.

Ranger Angela Loftus, who makes regular patrols to the hot springs, has seen people hike in Weber grills and fireworks. Once the drinks get flowing, she said, people don’t pick the most discreet rest stops.

“Unfortunately, I’ve seen visitors in the act of degrading this land,” she lamented.

But rangers say the potty problem isn't hopeless. Past education and enforcement efforts have worked. For example, in 2016 the service starting requiring bear canisters for anyone entering Conundrum. Compared to the previous year, reported incidents with bears dropped from 27 to zero.

Sam Brasch/CPR News Clothes often come off at the hot springs — and are then left behind for forest rangers. Nelson found a number of items on a recent patrol to the area.

The main hot springs pool sits just above treeline. By the time the clean-up crew arrived, a dozen hikers were already soaking in a circle, some with bathing suits, some without. The water reflected the cool orange of the evening sky. Craggy peaks towered overhead.

The time had come to ask visitors what they had done with their poop.

Four out of 13 brought wag bags. The rest said they were burying it, but would give the bags a shot at the next opportunity.

Jenny Gilfis and Caleb Wong were at the springs from Maryland to celebrate their engagment. They had read contradictory things about Conundrum: that it’s a gorgeous area, yet teeming with trash and human waste. They hadn’t seen or smelled the problem though.

“It’s beautiful. And perfect. And the best thing,” Gilfus said.

Each visitor wanted to help preserve the area just as it was on that cool, summer evening. They said they planned to carry out their trash. They had bear canisters or would get them right away. All claimed to have looked for designated campsites.

But those behaviors often feel noble. It’s a lot more inelegant to pack out your own poop.