Unusual Spike in "Rock Stacking" Prompts Intervention on Kootenay River

Kootenay National Park - Parks Canada is urging visitors to stop stacking or rearranging river rocks in the Kootenay River after staff removed roughly 15 human-made dams and rock structures this summer. The agency says the trend is becoming a growing threat to native fish and river ecosystems.

Bow Valley Insider learned of the issue after a Facebook post from Kootenay National Park prompted further questions. In response, Parks Canada confirmed that both the number and the size of rock structures discovered this year were unusual compared with previous seasons. Several were large enough that they survived high water and had to be dismantled by hand.

A photo shared by the park, which shows two staff kneeling in cold water moving large boulders back into place, illustrates how intentional some of the structures were.

“We removed approximately 15 human-made rock structures from the Kootenay River this summer,” said Catherine Lv, Public Relations and Communications Officer for the Lake Louise, Yoho, and Kootenay Field Unit. “Many of these structures were made using large boulders.”

Although these rock piles often come from what Lv described as “a place of curiosity and enjoyment,” the ecological consequences are serious. Parks Canada says it has seen rock stacking before, but the structures found this summer were more numerous and more disruptive than in past years.

Why moving a few rocks matters

To many visitors, a shallow stone dam might look like a harmless diversion. To a river system, even small disruptions can have outsized impacts.

“Rock dams alter the flow of a creek, changing depth, water velocity, temperature, dissolved oxygen and substrates,” Lv said. These man-made structures do not behave like natural riffles or log jams that fish have adapted to. Instead, they create obstacles that native trout cannot swim over.

Blocking movement, even temporarily, can shrink breeding populations and leave fish vulnerable to predators such as osprey and mammals that patrol shallow pools. In some cases, Parks Canada has found fish left stranded in drying pools or trapped inside the rock structures.

The Kootenay River is home to Bull Trout, Westslope Cutthroat Trout and Mountain Whitefish. These species already face pressure from warming waters, disease and habitat loss. “Young fry are present year-round and are especially sensitive to barriers,” Lv said. “Even small rock structures can block movement.”

Where the issue is growing

Most of the structures were found near the McLeod Meadows Campground. This area already faces periodic flooding and bank stabilization issues. Altering the river in this area can worsen those problems.

“This area has had past problems with flooding and bank stabilization,” Lv said. “It is important that visitors do not alter the flow around the campground or the footbridges.”

In previous years, most rock stacks were small and washed out naturally. This year was different.

“The number and size of the structures found on the Kootenay River this summer were unusual,” Lv noted. “Several structures were large enough to persist and required manual removal.”

How Parks Canada caught it

The discovery was not accidental. Staff routinely monitor waterways as part of aquatic invasive species work, waterfowl surveys and fish monitoring programs. These routine checks allowed crews to identify the rock dams early enough to intervene.

Could visitors face consequences

Although the agency focuses on education first, there are legal consequences for disturbing rivers inside national parks.

The federal Fisheries Act prohibits obstructing waterways in ways that block fish passage. A similar rule in the National Parks General Regulations prohibits actions that interfere with wildlife or natural features. Parks Canada emphasizes that tickets or fines are a last resort.

“Wardens have a range of enforcement tools,” Lv said. “But our preferred approach is always education.”

If you see a rock dam, do not dismantle it yourself

Parks Canada is asking for public help, but wants visitors to report the structures instead of wading in and moving rocks on their own. The riverbed can be slippery and large stones can shift unexpectedly.

“You can inform any Parks Canada staff of the rock structure,” Lv said. “Or call 1-888-WARDENS. Streams can be slippery and moving larger river rocks may cause injury.”

The agency is encouraging visitors to follow simple principles. Stay on designated trails, leave natural features where they are and avoid disturbing riverbeds.

A small action with big consequences

Rock stacking is often framed online as a harmless art form or meditative activity. But in the Kootenay River, which is home to sensitive fish populations and a dynamic water system, these stacks can become dangerous obstacles.

Even a short attempt at balancing a few stones can reshape water flow, push sediment downstream, weaken spawning grounds and cut off access to habitat. After this summer, Parks Canada hopes visitors will pause before moving a rock.

“Leaving natural features undisturbed helps protect the park’s ecological integrity,” Lv said. “It also supports the health of park waters.”