Lazy rivers

The lazy river is an oasis within an oasis: a break from a water park’s more kinetic entertainment. Its only requirement is that you commit to drifting along on a carefully calibrated current.

This relatively gentle ride might seem trivial compared to more forceful chutes and flumes, but every bend and entryway presents a challenge to engineers trying to keep it gentle and constant. It’s an even greater design feat to add just the right amount of turbulence, for a more natural feel.

As lazy rivers get more creative, the design process becomes more difficult. That’s why some water park designers see themselves as part of a long tradition dating back to “the Baroque era geniuses—known as fontanieri or fountaineers—who built extravagant gravity-driven water features at estates like Versailles or Villa d’Este,” writes Karrie Jacobs in Curbed. So kick back and relax! We’re already on our way.

To keep hundreds of thousands of gallons of water moving, builders line the channel with grates. As a small percentage of the water seeps through the bars, it’s pumped back into the system through a series of downstream jets. But lazy rivers twist, turn, and open up so riders can enter and exit—all things that “disturb the flow and cause local energy losses,” according to an analysis by civil engineer Bruce M. McEnroe.

To keep things flowing optimally, the placement of each jet has to be considered. “The angle is important,” Terry Brannon, president of engineering firm Brannon Corporation, tells Pool and Spa News. “Too steep an angle, and the water jet bursts through the surface like a large bubbler. Too flat an angle, and all the momentum is imparted to water at the floor and is not very efficient.” Jets need to be more forceful at river bends, for example, so riders don’t stall out.

5,280 ft (1,600 m): Length of the longest lazy river, at BSR Cable Park in Waco, Texas

$780: Nightly fee for a Scottsdale, Arizona Airbnb with its own lazy river

3 miles per hour (4.8 km per hour): Top speed of a lazy river

0.015: Typical Manning roughness coefficient of a lazy river

$900,000: Estimated cost of a 500-ft (152-m) lazy river

3.5 ft (1 m): Typical depth of a lazy river

10 baht (about $0.50): Price to ride an inner tube on Princess Panthip Chumbhot’s estate in Thailand, in 1965

Tubing emerged in the 1910s, when parents began putting spare tires to good use as floatation devices.

But the lazy river’s origin story gets murkier from there. In July 1941, Life magazine reported that David Breault of Somerset, Wisconsin had invented river tubing a few years prior when he began organizing “floating parties” on the all-natural Apple River, as a way to promote his nightclub. In 1965, Sports Illustrated reported that Thailand’s Princess Panthip Chumbhot brought 100 inner tubes to her countryside estate so that guests, and paying customers, could float down the river.

It’s not clear who channeled this wild idea into an artificial experience, but by 1980, there was one running along the perimeter of the Schlitterbahn, a legendary Texas water park. It wasn’t exactly “lazy”—Texas Monthly describes “light rapids, quick drops, and backwater eddies.” But it sparked a trend, and not just at water parks.

“Down below, the Lazy River runs, a neon blue, a crazy blue, a Facebook blue.” —Zadie Smith in her short story “Lazy River”

“Thank you, Lazy Rivers, for combining my love of crowded public pools with my love of traffic jams.” —Comedian Jimmy Fallon

In 1977—at just 22, with no formal education in engineering, physics, or any other discipline—Jeff Henry decided to create a water park from scratch on his family’s property in New Braunfels, Texas. The Henry family opened Schlitterbahn (German for “slippery road”) to the public in 1979. Under Henry’s leadership, they built lazy rivers, the Boogie Bahn (an artificial surface for real boogie boarding), the “watercoaster,” and more.

But in 2016, 10-year-old Caleb Schwab was decapitated on the Kansas City Schlitterbahn’s Verrückt waterslide, which stood taller than Niagara Falls. The accident brought a good deal of scrutiny to Henry, who once described his engineering methods as a “trial and error” process, and to the Schlitterbahn parks. In 2018, Henry, his long-time collaborator John Schooley, and the Schlitterbahn construction company were charged with aggravated battery, aggravated child endangerment, and second-degree murder, by Kansas City prosecutors, but the charges were eventually dropped the following year.

Scientists at the University of Alberta in Canada calculated that there are 20 gallons (76 liters) of urine on average in a 220,0000-gallon (833,000-liter) commercial swimming pool. That’s just .01% of the total volume… but still.

Hoagy Carmichael co-wrote the original “(Up A) Lazy River” in 1930. The pop standard has been covered more than 60 times since, including renditions by Louis Armstrong, Bing Crosby, and Michael Bublé. It’s the perfect tune for a float—“Blue skies up above / everyone’s in love,” Carmichael croons—but don’t limit yourself to a single stream. Here’s a river-themed playlist that will really keep you rolling.

In 2015, Louisiana State University in Baton Rouge embarked on an $85 million makeover of its student athletic facilities. The redesign, funded by a $135 increase in student fees, included construction of a lazy river.

The clapback was quick, with every op-ed section from the Wall Street Journal to the Huffington Post deriding the lapping waves of luxury at a time when public universities suffer from dwindling state funding, and students find the financial barriers to college rising higher each year. “The symbolism of this is worse than the reality of it,” a finance expert at the College Futures Foundation told Inside Higher Ed at the time. And LSU officials were quick to point out the earmarked money couldn’t have been spent any other way. But it only fanned the flames.

The controversy wasn’t enough to deter other campuses—but the University of Central Florida’s “recovery cove” was funded by a private donor.

In the US, water park (and amusement park) safety regulations are left up to individual states to determine. The lack of federal oversight means that there is no single agency keeping track of injuries and deaths at water parks, and a wide discrepancy in safety standards and their enforcement. The death of Caleb Schwab at the Kansas City Schlitterbahn was far from the first water park tragedy. In the 1980s, Action Park in Vernon, New Jersey became widely known for being dangerous—insanely so, by modern standards. As Jack McCallum writes in a long retrospective for Sports Illustrated, “anyone involved in Action Park knows it was a product of a different time, a different collective mindset about risk.”