Dangers of the Cumberland River: How water depth, current and temperature impact people

As Tennessee authorities continue their search for missing University of Missouri student Riley Strain this week, the Cumberland River has become a key setting in the unfolding drama.

But, is the Cumberland River really dangerous?

The Office of Emergency Management has launched boats on the river twice as part of a coordinated search for Strain, 22, with the Metro Nashville Police Department. The university student was last seen Friday walking near Gay Street and 1st Avenue, according to Nashville Fire Department spokesperson Kendra Loney.

His friends reported him missing the next day.

The area where Strain was last seen was in a brushy area with cliffs that would make it nearly impossible for the missing student to have fallen into the river, Loney said, but the failed boat searches on Tuesday and Wednesday have raised some serious concerns about the safety of river, itself, concerns that one Nashville business owner couldn't help but raise.

The Cumberland River spans 688 miles, cutting a path through southern Kentucky and Middle Tennessee before connecting to the Ohio River. It runs through two major cities: Clarksville and Nashville. There are eight dams along the river, and the Tennessee Wildlife Resource Agency notes that it is often used by large barges for transporting goods.

Tennessee Wildlife Resource Agency Captain Josh Landrum said the Cumberland River presents several dangers to people, especially at night and in cold temperatures.

"Undertows can be present anytime there is wind and strong currents in river systems. However, typically through the downtown area, the river is narrow, and the river current is the greater danger. A strong river current alone could cause even a good swimmer difficulty in getting back to the shoreline if they were to fall in," Landrum said.

Cumberland Kayak & Adventure Company operations manager Dylan Schultz said there are several variables that could cause even more danger for those navigating the river.

Among those issues is how fast the water travels.

Water velocity on March 8, when Strain was last seen, was measured at 3.81 feet per second, according to United States Geological Survey (USGS) data. Velocity peaked at 10:30 a.m. on March 9, when it was measured at 4.0 feet per second.

"Day-to-day, the current varies," Schultz said. His company operates along a three-mile stretch of the Cumberland between Shelby Park and the downtown area. "It's not usually at a level where it is swift, but it would be difficult to swim against the current."

For those who are curious, the Cumberland's current runs west and northwest through Nashville, Schultz noted.

The National Oceanic and Atmospheric Administration defines swift currents as those with speeds of up to 8 feet per second.

But water velocity isn't the only factor to consider on the river. Depth is also important.

On March 8, the USGS reported that the river was 24.66 feet deep at 10 p.m. It has since changed, with the water level rising to 20.71 feet as of 1:30 p.m. Wednesday, the USGS said.

Despite those readings, Schultz said much of the Cumberland River is shallow enough to stand in. He estimates the average person can stand in the river anywhere between 10-15 feet from shore.

But, watch out, 'it does drop off quickly," he warned.

Perhaps the biggest challenge someone in the river might face, especially at night, comes from the transportation barges that float along the Cumberland combined with low air temperatures.

On March 8, temperatures were as low as 56 degrees, officials said. Landrum pointed out that water temperatures would have been in the 50-degree range, making hypothermia a possibility, especially if someone is unable to get out of the water quickly.

So far, the searches at the Cumberland have proven unsuccessful as local officials continue to hunt for the missing student.

Strain is 6'5" tall with a thin build, blue eyes and light brown hair.

He was out with a group of Delta Chi fraternity brothers Friday night when he got kicked out of Luke Bryan's bar at about 10 p.m. He hasn't been seen or heard from since.

The bar has said on social media that it is cooperating with authorities to aid in the investigation.

Anyone with information about Strain's whereabouts is asked to call Metro Police at 615-862-8600.

This article originally appeared on Nashville Tennessean: Cumberland River in Riley Strain case highlights river's dangers