Riverlorian.com

Dams are built to back up water in a reservoir for a variety of reasons. Dams are hazardous both above and below the dam. These wall-like structures pool the water as it flows over the crest and drops to the lower level.

This drop creates a hydraulic, which is a backwash that traps and re-circulates anything that floats. Boats and people have been caught in this backwash. A person caught in the backwash of a low-head dam will be carried to the face of the dam, where the water pouring over it will wash him down under to a point downstream called the boil. The boil is that position where the water from below surfaces and moves either downstream or back toward the dam. A person who is caught in a low head dam struggles to the surface, where the backwash once again carries him to the face of the dam, thus continuing the cycle.

To complicate matters, these dams are usually loaded with debris, such as tires and logs on the surface and rocks and steel bars just below, posing additional problems should a person get trapped in this dangerous structure.

Dams do not need to have a deep drop to create a dangerous backwash. During periods of high water and heavy rains, the backwash current problems get worse, and the reach of the backwash current is extended downstream.

Small low-head dams that may have provided a refreshing wading spot at low water can become a brutal death trap when river levels are up. Simply put, it is not the drop of the dam which is the lethal danger, but the backwash current. This backwash current is governed by volume of water and flow.

From downstream, you may not realize the danger until it's too late. From upstream, low-head dams are difficult to detect. In most instances, a low-head dam does not look dangerous, yet can create a life-threatening situation. You should always pay attention to warning signs, markers or buoys and keep well clear of low-head dams. If canoeing or boating above any dam, always have an anchor and plenty of line ready in case of motor failure or other emergency. In other words, be ready to put the breaks on.

Capsizing, Swamping or Falling Overboard:

Capsizing is when a boat turns on its side or turns completely over. Swamping occurs when a boat stays upright and fills with water. Sometimes a person falling overboard from a boat causes the boat to capsize or swamp. Regardless, the outcome is the same?people are in the water unexpectedly.

To help prevent and prepare for capsizing, swamping, or someone falling overboard, follow these guidelines.

• Make sure that you and your passengers are wearing life jackets while the boat is underway.
• Attach the ignition safety switch lanyard to your wrist, clothes, or life jacket.
• Don't allow anyone to sit on the gunwale, bow, seat backs, motor cover, or any other area not designed for seating. Also, don't let anyone sit on pedestal seats when operating at a speed greater than idle speed.
• Don't overload your boat. Balance the load of all passengers and gear.
• Keep your center of gravity low by not allowing people to stand up or move around while underway, especially in smaller, less-stable boats.
• In a small boat, don't allow anyone to lean a shoulder beyond the gunwale.
• Slow your boat appropriately when turning.
• Don't risk boating in rough water conditions or in bad weather.
• When anchoring, secure the anchor line to the bow, never to the stern.

If you should capsize or swamp your boat, or if you have fallen overboard and can't get back in, stay with the boat if possible. Your swamped boat is easier to see and will signal that you are in trouble. Also signal for help using other devices available (visual distress signals, whistle, mirror).

• If you made the mistake of not wearing a life jacket, find one and put it on. If you can't put it on, hold onto it. Have your passengers do the same.
• Take a head count. Reach, throw, row, or go, if needed.
• If your boat remains afloat, try to reboard or climb onto it in order to get as much of your body out of the cold water as possible. Treading water will cause you to lose body heat faster, so try to use the boat for support.

If your boat sinks or floats away, don't panic.

• If you are wearing a life jacket, make sure that it is securely fastened, remain calm, and wait for help.
• If you aren't wearing a life jacket, look for one floating in the water or other floating items (coolers, oars or paddles, decoys, etc.) to help you stay afloat. Do your best to help your passengers find something to help them float and stay together. If you have nothing to support you, you may have to tread water or simply float. In cold water, float rather than tread to reduce hypothermia.

If someone on your boat falls overboard, you need to immediately:

• Reduce speed and toss the victim a PFD, preferably a throwable type,unless you know he or she is already wearing a life jacket.
• Turn your boat around and slowly pull alongside the victim, approaching the victim from downwind or into the current, whichever is stronger.
• Stop the engine. Pull the victim on board over the stern, keeping the weight in the boat balanced, especially in small boats. Remember, swimming to shore should be considered only as a last resort. Small craft boaters need to be especially careful to avoid falling overboard. Falling overboard and drowning is the major cause of fatalities for small boats. 
• To prevent falling overboard:

• Keep centered in the boat with your center of gravity low in the boat. Always keep your shoulders between the gunwales.
• If possible, don't move about the boat. If you must move, maintain three points of contact. That is, keep both hands and one foot or both feet and one hand in contact with the boat at all times.
• Evenly distribute and balance the weight of persons and gear within the boat, keeping most of the weight low. It is extremely important not to overload a small boat.

• Attach 7-8 feet of galvanized chain to the anchor. The chain aids in setting the anchor by lowering the angle of the pull as the chain sinks and lies on the bottom. It also will help prevent abrasion of the anchor line from sand or rock on the bottom. Most anchors grip by digging into the bottom when the line is pulled horizontally. Any upward pull may break the anchor loose.
• Be sure the anchor line is strong and long enough to anchor your boat. A good rule of thumb is that the length of the line should be at least seven to ten times the depth of the water where you are setting anchor.
• Since an anchor can be a safety device in an emergency situation, store the anchor and its lines in an accessible area. If the engine breaks down, you may need to anchor quickly to avoid drifting aground.

Check the weather conditions before going out and be prepared for bad weather. Take rain gear and a bailing bucket. With boats equipped with bilge pumps, make certain that they are in good working order before setting out. 

The photo shows a great program sponsored by the U.S. Army Corp of Engineers along the Cumberland River. "Kids Don't Float" is the message at the loaner life jacket station. 

Here's a little known fact. 90% (unconfirmed statistic) of men found drowned from falling overboard while fishing are found with their fly open. If you don't want to go below to use a head or porta potti or don't have such creature comforts then get a small plastic pot. Don't stand out by the rail or near the edge of a boat. Its a lot easier to lose your balance than you might think.