Looking to escape? Hike into a canyon at this Idaho state park to see water as blue as the Caribbean Sea

BOISE – Idaho is known for all kinds of natural wonders – mountains, canyons, waterfalls, unique rock formations. But tropical waters?

One increasingly popular Southern Idaho trail follows a basalt canyon rim before taking hikers down into the canyon itself to walk along bright blue-green water reminiscent of the Caribbean Sea.

The Box Canyon Springs Trail is in the Earl M. Hardy Box Canyon Springs Nature Preserve, part of Idaho’s Thousand Springs State Park. The preserve is about 115 miles east of Boise near Hagerman, Wendell and Buhl.

Thanks to its beauty, Idaho’s booming population and recent developments near the trail, visitation nearly tripled between 2019 and 2020, the Idaho Department of Parks and Recreation reported. It makes a perfect trip in combination with visits to Thousand Springs’ other park units or a paddle to Blue Heart Springs, a nearby cove off the Snake River that is accessible only by boat and boasts more clear, turquoise waters.

Park’s pure blue waters stay underground for years

The Box Canyon Springs Preserve is a relatively new addition to the Idaho Department of Parks and Recreation’s properties. The Nature Conservancy, which purchased the property in 1999, completed its transfer of the preserve to the state in 2016. Juelie Traska, park ranger at Thousand Springs State Park, said the spring’s water supply comes from the Snake River Plain Aquifer, originating from water sources including the Big and Little Lost Rivers.

“When (the water) comes out, it comes up underground from the springs or through the canyon walls,” Traska said. “When it travels underground, it filters itself through all the basalt rock.”

Traska said the process purifies the water and adds minerals, leaving the water a pristine color unlike other water sources in the area.

“When you look at it compared to the Snake River … it’s really blue where the Snake River’s kind of greenish,” she said.

In the past year, the Box Canyon Springs Preserve unit of Thousand Springs has seen a huge uptick in visitors. Visits increased 180% between 2019 and 2020, Parks and Rec reported in January . That was the largest percentage increase of any park in the state – though with 75,000 visitors last year, it was still one of the less-visited parks.

Traska said the increase in visits was likely due in part to parking and road upgrades. Previously, the site had only a small parking area off of West Point Road. Visitors had to follow a rough dirt road the last half-mile to the canyon. Recently, the department paved that road and added a larger parking lot just steps from the canyon. A paved sidewalk brings visitors to an overlook with views of two of the largest, brightest pools in the preserve, making the attraction accessible to a much larger audience.

The pandemic may have also played a part in bringing more visitors – the department’s overall numbers smashed the record in 2020 – but Traska said it’s also likely that Box Canyon Springs is just drawing more attention.

“(I think it’s) word of mouth,” she said. “People are like, ‘Wow, I can’t believe this beautiful sight is out here in the middle of the desert.’ ”

Hike features steep canyon descent, stunning views of springs

The 3.5-mile hike starts just past the paved overlook. Hikers must climb a small stair bridge to cross a barbed-wire fence before starting on the trek. The next half-mile follows the rim of the basalt canyon, where you can see the springs running 200 feet below and watch birds of prey circling above. There are plenty of places to stop and take in the view, but watch your step – there are loose rocks strewn across the path, and rattlesnakes frequent the area when the weather warms.

The descent into the canyon can be tricky at times. A cable railing follows the trail as it winds 200 feet down to the canyon floor. Along the way, expect to pick your way through large rocks, sidestep down steep grades and push past overgrown foliage.

“The terrain getting down into the canyon may not be for everyone,” Traska said. “It’s a challenge. People going down there have gotten in trouble – they get down there and can’t get back out.”

At the bottom of the canyon, the trail levels out and meanders near the springs, offering glimpses of the rushing water, which flows out to meet the Snake River. The brush is still dense in some parts, and Juelie said poison ivy is common in summer. Keep an eye out for the plant and consider wearing pants and long sleeves to avoid a rash.

The route will take you right next to a beautiful waterfall, which crashes into a bright blue pool. The path through the bottom of the canyon is about a mile, crossing the springs in a few spots. Near where the canyon meets the Snake River, there is an exceptional blue pool where you can watch spring water flow from the ground. Traska said water can remain in the Snake River Plain Aquifer for hundreds of years before it resurfaces at Box Canyon Springs.

After exiting the canyon, the trail turns into a gravel road that switchbacks up to the canyon rim, rising about 200 feet in elevation over about half a mile – roughly half of the 400 or so feet of elevation gain for the hike. From here, it’s a little over a mile to loop back to the parking area. Traska said this gravel route is a good option for hikers who might not feel comfortable attempting the steep, rocky canyon descent. Instead, they can treat the hike as an out-and-back.

Weeds raise worries

Like Box Canyon, nearby Blue Heart Springs has become a popular visitor area. Just downstream from the preserve, Blue Heart is a cove off the Snake River accessible almost exclusively by boat or kayak. The area, owned by the Bureau of Land Management, is not part of the state park. The area is not part of the state park (it’s owned by the Bureau of Land Management). Recently, the Idaho State Department of Agriculture found noxious weeds there.

Jeremey Varley, manager of the agency’s noxious weeds program, said the Department of Ag found two types of milfoil, an aquatic plant. One type was a native plant, while the other, Eurasian milfoil, is an invasive plant classified as a noxious weed.

“There’s nothing to keep that plant in check, and it will grow and proliferate until it completely fills that water body’s ecosystem,” Varley said. “It will choke out native vegetation.”

Varley said Eurasian milfoil isn’t unheard of in the area – in fact, the department was already aware of populations of the plant in nearby parts of the Snake River. He said it’s not clear if the plant spread to Blue Heart Springs on its own or if visitors may have played a role.

Milfoil can be spread when parts of the plant are torn off by swimmers, paddles or boat motors, and a section as small as an inch can proliferate into a new plant.

Varley said he’s not certain whether the weed could obscure the blue water. Other plants, like water veronica and watercress, are an indicator of the water’s health and can be seen in the clear pools throughout the canyon. But Eurasian milfoil can grow algae that could impact the springs’ color and clarity. Additionally, the weed can lead to stagnant water, which could cause fish to die off due to a lack of oxygen.

Varley said the Department of Agriculture will be removing the weeds at Blue Heart this summer and surveying Box Canyon to ensure the Eurasian milfoil hasn’t spread to its waters.