Water Sports and the Environment

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LOCKS

Locks are used to move boats from one water level to another.

• At larger locks, the “lockmaster” controls all movement in and out of the locks.
• Contact the lockmaster on marine radio channel 13 VHF-FM. If you receive no response on the radio, try two long and two short blasts from your horn and follow the light signals that are displayed at each entrance to the lock.
• A lighted signaling system, similar to a streetlight, helps the lock master control movement.
  Red = stop, yellow = caution, and green = go.
• Have everyone wear a life jacket. Put out fenders and have lines at the ready.
• Drive the boat into the lock slowly and cautiously.
• The gates will close and the water will either rise or fall, depending on if you are going to a higher or lower water level.
• As soon as the water in the lock reaches the proper level, the gates are opened and the light turns green. Release all lines and exit slowly.

LOWHEAD DAMS

Low-head dams (manmade concrete structures or natural rock structures) that can be only a few feet wide to as large as the entire width of a river. They should be avoided in most cases. With strong current flowing over lowhead dams, they are potential drowning machines. Once caught in the downstream-side hydraulic, it is nearly impossible to get out even if wearing a life jacket..

The best way to maneuver around lowhead dams when using a canoe or kayak is to portage. Portage means to remove your craft from the water well away from the dam, and carry it around the dam to a new launching point.

• The downstream side of a dam is the most dangerous as this is where the hydraulic is created.
• Boats trapped against the downstream side quickly fill with water and capsize, throwing occupants into the dangerous waters.
• When caught in the hydraulics of a low-head dam, you are carried to the face of the dam, where the water pouring over it will wash down under to a point downstream called the boil.
• The boil is a position where the water below surfaces and moves either downstream or back toward the dam. A person caught in a boil dam may surface, only to be caught in the backwash again and carried to the face of the dam, continuing the cycle. Even with a life jacket on, the hydraulic may continue to pull a person under. The tremendous force of the hydraulic may pull off a poor fitting life jacket from a struggling person.
• Dams do not need to have a deep drop to create a dangerous backwash.
• During periods of high water, the backwash current problems get worse, and the length of the backwash current is extended downstream.

Although low-head dams do not always look dangerous, they can create a life-threatening situation. You should always know the local area, follow warning signs, markers or buoys, and keep well clear of low-head dams.