Beyond an easy water reading, paddlers must be able to recognize river hazards. These features add consequence but room an inescapable part of to run rivers. That being said, the best means to respond come river risks is to avoid them at any time possible. Below are the 6 most usual hazards and how to recognize and minimize their risk.

You are watching: What are strainers on a river

1. Strainers

Just choose a kitchen strainer for pasta, river strainers (or sweepers) are obstructions that allow water to pass however retain larger objects. They have the right to be organic objects or man made dangers such together trees, rebar, drain grates, and bushes. Some methods strainers appear in rivers are from trees falling, human construction, or flooding bringing new objects downstream.


Portaging around A Strainer

Paddlers should stay ~ above the lookout for strainers specifically after heavy rains or flooding events. At high flows, vegetation ~ above the financial institutions can additionally become dangerous together it is submerged. The best way to protect against a strainer is to aggressively paddle or swimming away as soon as spotted. If you space swimming and the strainer is unavoidable, swim difficult to gain yourself top top top and also over that to defend your airway.

2. Sieves

Sieves are comparable to strainers yet are obstructions make by rocks or the riverbed. They are normally boulder-choked areas that permit water to pass but would block a person or boat. Generally, obstacles force water around them, often developing a pillow on their face. However, sieves have actually enough an are for water, however not humans, to pass through. If sometimes tough to recognize, water will merely disappear into teams of rocks rather of gift displaced.


Blossom Bar top top the Rogue flow was developed by a substantial landslide out of a side canyon.

Once again, sieves appear and disappear based on river flow and are red flags come avoid. They sometimes take increase the totality river or are features in rapids.

3. Foot Entrapment

The bottom that a flow is uneven, which may seem obvious, yet becomes hazardous when merged with current. Simply one square meter (35 cfs) of water weighs 1000 kg (2204 lbs). If a swimmer does no pick your feet up they can get caught and pushed confront down by the weight of the river.

These instances are exceptionally dangerous due to the fact that rescuers only have actually a little time to aid the swimmer. If that is safe, gain to the human being as conveniently as feasible to lift their airway the end of the water. The ideal practice to avoid these situations is to never ever stand increase in the river. In addition, swimming shallow water in a defensive swimming position (nose and also toes out of the water, facing downstream) will aid reduce foot entrapments.

4. Holes

A hole is just one of the most typical river attributes you will hear world talk about. Also there room a lengthy list of varieties of holes. Ledge hole, river wide hole, small hole, large hole, recirculating hole, and my favorite, huge macking holes. These space all similar and developed when water flows end a rock, heads towards the bottom that the river, and also turns earlier onto itself.


Cataraft upper and lower reversal at the Beatdown feet on the West Fork the the Hood River.

The toughness of the hole depends on the elevation change of the water and how lot of the water is able to flow out and away from the rock. When holes have the right to flip and hold boats and people in your churning water, lock are likewise used bye people to surf and also do tricks.

5. Undercuts

The names quite much defines this hazard. Rocks or rock walls where there are pockets because that water come go however not constantly people and also boats. This are particularly dangerous because you have the right to never be certain where the water goes once it disappears. One more scary facet is that they have the right to appear and disappear as the water rises and falls.

6. Flow

How much water can play a substantial roll in what a river will be like. Together the water rises some rivers difficulty rises. Much more obstacles of the over obstacles deserve to come right into play and become dangerous. Also an ext water frequently means couple of eddies to slow-moving down and regroup. A flip or swim have the right to be a huge challenge to attend to so boaters really need to be prepared for the added challenge.


High water Velvet falls on the middle Fork of the Salmon

As the water autumn you might think a river will gain easier. However, that isn"t always the case. Much less water may bring the unknown obstacles in play. Your neighborhood run may end up being unrecognizable when the water drops. Unknown undercut rocks, strainers, and also sieves deserve to be unexpected and also cause some problems.

See more: How Far Is Lubbock To Houston From Lubbock, Lubbock To Houston Distance (Lbb To Iah)


Low water Velvet drops on the center Fork of The Salmon

Learning the typical names and how come recognize dangers aids in your personal safety, communication while boating, and scouting. Awareness of your own skills matched v those of the group matched through the river. Plan ahead and prepare as these hazards are component of advancing as a boater. Can always take a smaller boat on an simpler run.