Swiftwater Strategy

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Floods kill more people than any other natural disaster in the United States. First responders often face the grim scenario of a victim trapped on a stationary object amid the floodwaters, or worse, adrift in the rushing torrent. Few places exist where flooding is not an issue, and few situations are more challenging or more dangerous.

As flood season nears, following is a quick refresher on swiftwater characteristics and training.

 

Swiftwater Characteristics

There are three main characteristics of swiftwater. First, it's powerful. Water weighs 62 lbs. per cubic foot (cf), and when those cubic feet move, they exert tremendous force. For example, the water moving through just one turbine in Arizona's Glen Canyon Dam produces more than 155,000 horsepower.

Second, swiftwater is relentless. Waves in the ocean come and go, but if you get pinned against an obstacle or strainer in a river, the relentless crushing force of the water won't dissipate. Even the strongest rescuers are no match for the force of a rushing river.

Third, swiftwater is predictable. This is the most important characteristic to the rescuer. With training and experience, you can predict with certainty where both safety and danger points are located on a river. When it comes to hydrology, there's little difference between the Snake River, the Colorado River and your local waterway. Water behaves the same way when it moves over and around objects, no matter where they are. This knowledge is the rescuer's greatest asset.

 

Survival Strategies & Training

One of the single most important things you can do to increase your chances of survival during a swiftwater rescue is to wear an appropriate personal flotation device (PFD). Rescuers still drown during swiftwater incidents because they were wearing turnouts instead of a PFD. Remember: Don't allow anyone not wearing a PFD within 10 feet of a river.

Another critical survival strategy: Practice swimming a section of a river in a structured training setting with backups in place. Swimming a river and catching eddies (horizontal reversals of flow) is fun, and rescuers get a good feel for the power of the river and how to find its safe zone. To formalize your practice, consider the following swim-skill drill.

 

The Swim-Skill Drill

Setting: On a body of water with some current (although a fast-moving river is ideal, it's not necessary)
Duration: Approximately 4 hours
Objective: To teach students how to negotiate obstacles and catch eddies, gain confidence in the water and learn to swim across strong current to a specific eddy.

  • Start with a good safety plan and briefing, as some rescuers will be challenged by the swimming conditions.
  • Make sure each rescuer is properly fitted with a quality PFD, helmet and appropriate thermal protection.
  • Point out all known hazards on the river, and emphasize that unknown hazards may exist.
  • Set ground rules for a buddy system, and define a clear maximum travel point (or a landmark on the side of the river that everyone agrees not to pass).
  • Demonstrate the safe swimming position, which is feet pointed downstream, and explain the concept of the ferry angle-angling your body at 45 degrees to the current so it can move you in a particular direction. This is how ferries used to move back and forth across rivers.
  • Point out specific hydraulic features (including eddies), and explain the swim route, noting obstacles to avoid and the location of the exit eddy.
  • At some point during the swim, instruct the students to practice going over a strainer prop (strainers are any object in a river that allows water to pass through but traps a person). Set this up in a spot with a strong current where an instructor can hold at least one side of the prop. Instruct each student to float down, letting their legs go under the prop, and then try to climb over it without pushing off the bottom. After being caught by the strainer, instruct each student to swim over the prop with an aggressive crawl stroke. Note: An instructor should demonstrate this first. Good technique includes maintaining eye contact with the hazard and pushing down on the object as you climb over.
  • Swim in pairs, and keep an eye on each other. Note: An instructor should go first to demonstrate the drill and safety check the route; the second instructor should sweep (go last).

Current Issue

October 2017
Volume 12, Issue 10
1710FR_C1.pdf
Pennwell