Swiftwater Rescue
What this domain covers
Swiftwater rescue covers moving water where current is the dominant hazard - rivers, flash-flood channels, and storm drains. It tests hydrology, hazard recognition, swimming, and tethered and untethered rescue systems. Force on a body or a vehicle rises with the square of velocity, so doubling current speed roughly quadruples the load.
Hazards
- Strainers: water passes through a tree or fence; the person does not.
- Sieves: water passes under or through a constriction with no air space.
- Low-head dams: recirculating hydraulics that trap and recycle.
- Undercuts, bridge pilings, and debris pockets.
- Foot entrapment: the most lethal mistake in shallow current.
Techniques
- Defensive swimming: on your back, feet downstream and on the surface, head up, angled about 45° toward the nearest shore.
- Aggressive swimming: on the front, angled downstream, for ferrying and eddy-hopping.
- Throw bag: throw upstream of the victim so the rope floats into them; belay the bag, and use a quick release on any tether.
- Tension diagonals and V-lowers move patients across current. A tethered 'live bait' rescuer needs a quick release operable under load.
- Never tie a rope directly to a rescuer or a victim without a releasable system.
Worked example
A kayaker is pinned against a strainer mid-channel. You set a tension diagonal from an upstream anchor to a downstream anchor, cross on the upstream side of the line, and approach from downstream with a tethered rescuer on a quick release. Approaching from upstream pushes the rescuer into the strainer too.
Traps
Standing in knee-deep current. Rigging a tether with no quick release. Throwing a bag with no belay. Reading a rapid class only as difficulty rather than as a current hazard.