Low-head dams pose a serious danger
to vessel operators
. Surface currents below low-head dams can suck vessels toward the face of the dam. Currents above low-head dams can sweep vessels over the dam. The recirculating currents and turbulent waters below these dams can swamp vessels and drown boaters.
Where is the hazard of a low-head dam?
Even low head dams, which sometimes seem to have a very small drop, are dangerous, because
the water going over the dam circulates back toward the face of the dam and can trap a person or boat
.
Which part of a low-head dam is the greatest hazard from a strong circulating current or boil?
In fact, it is the most dangerous type of dam.
Water going over the dam creates a strong circular current, called
the backroller
or the boil, at the base of the dam. The backroller can trap your boat or board and pull you under the water.
What do low-head dams do?
Usually made from concrete, the purpose of a low head dams is
to raise the water level upstream on a river
. This can assist with navigation of the channel by boats, create a drop for generating hydropower, and make water available at intakes for water supply and irrigation.
What should you keep in mind when approaching a low-head dam?
If you come across a low-head dam,
remain calm and paddle to the riverbank immediately
. Portage is the best way to go about it – get out and carry your kayak around the dam.
How can you tell if you have a low head dam?
Know hazard locations
Know hazards along your route and plan to portage around them. Low-head dams can be difficult to locate and are usually not marked. When looking downstream,
a smooth horizon line where the sky and stream meet or concrete/stone retaining walls
may indicate a low-head dam.
How do you prevent low-head dams?
The most important tip is to remember — “Keep Your Distance, Keep Your Life”:
Always stay a safe distance away from dams both upstream and downstream
to avoid drowning. There are many free resources available to aid in better understanding the dangers of low-head dams and the importance of this issue.
What if you fall in a dam?
If the dam has an open discharge system with consistent flow, you might break a few ribs, bump your head, etc. If you fall down this dam, you may risk drowning and also
maybe a water spilled brain
, but you may actually survive because there is lots of water and a raging current ro keep you away from rocks.
How are low head dams built?
A low head dam is
designed and built such that water flows continuously over the crest from bank to bank
. If water levels rise downstream, a submerged hydraulic jump can form which produces an upstream directed current that traps any recreationist who might go over the dam.”
What happens if you swim in a dam?
Surfaces can be extremely slippery and cause you to fall in the water. Don’t swim in any rapidly moving water. You
could quickly be transported into the DANGER ZONE
. When recreating in a river, be aware of the water level and check upstream frequently for any sign of increasing currents or rising water levels.
What we know and don’t know about low head dams?
Low-head, or run-of-the-river, types of dams – usually spanning the entire river or stream – can
present a safety hazard to the public
because of their capability to produce dangerous recirculating currents, large hydraulic forces, and other hazardous conditions sufficient to trap and drown victims immediately …
Which is a dam with low head of water?
A weir /wɪər/ or low head dam is
a barrier across the width of a river
that alters the flow characteristics of water and usually results in a change in the height of the river level. They are also used to control the flow of water for outlets of lakes, ponds, and reservoirs.
What are high head dams?
High Head. Head
differences of 100 meters or higher
are considered high head. In this type of plant, water travelling through the turbine comes from a significantly higher elevation, meaning that the system needs a smaller volume of water to produce an equivalent amount of energy.
Is it safe to kayak near a dam?
Most of the waters it contains are perfectly safe
, if you observe basic boating precautions. However, if you’re in the water near a dam, powerhouse or lock, you need to be aware of some potential hazards, and familiarize yourself with the systems TVA uses to communicate them to you.
Can you kayak over a dam?
Once you are out of the water,
you can circumnavigate the dam by portaging your kayak around it
. If you choose to do this, then you will need to move a reasonable distance down the river from the dam, as the area of disrupted water it causes can be extended by a significant distance.
What should you do with your float plan?
What Information Should a Float Plan Contain? A Float Plan
should be filled out before departing on your trip
. Leave it with someone who you can rely on to notify the proper authorities should you not return at the planned time. Vessel information: size, type, color, engine etc.
