WHITE WATER PRACTICE SESSIONS - RIVER READING AND SAFETY Mike 2 nd Orleans.
Post on 14-Dec-2015
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Transcript
Introduction
• Introduction
• River Reading
• Clothing and Equipment
• Procedures/Signals
• Dangers
• Proper “Swimming” Technique
Approximately 50 minutes
Concepts of River Flow
• Volume – really “flow rate”– Amount of water passing a point per unit
time
• Gradient– Average steepness or slope
• Velocity– Speed and direction of current– Depends on volume, gradient, obstacles,
river bed, river course, etc
River Formations – Constrictions• “white water” happens when the current
speed up• Caused by narrowing of banks, rocks,
shallow bottom• Called “white” due to air bubbles – less
floation
Eddies and Eddy Lines• Water passes around
rock and speeds up
• Water behind the rock actually flows upstream
• Line between the water flowing upstream and down stream – sharp near object
• Also occur at river edge
Obstacles
• Simple eddy behind a rock
• Increased water flow, water pours over rock, becomes a “pillow”
• Smooth flowing over rock, shallow
Obstacles (continued)•Water flow increases, riffles become “curling waves”, have white foaming tops
•Further increase in volume and velocity, larger waves, continuously breaking, upstream direction
Obstacles (conclusion)• Holes: flow continues
to increase, curling waves create circulating water
• Ledges: long structure extending over part of river, drops upwards from 2-3 inches, in the extreme a water fall
• Recognized by straight line of foaming water
“GOOD” FEATURES
• Eddies – play the river by eddy hopping, pause to scout/relax
• Downstream “V”s - show deep water channel between obstacles, dark water tongue
“GOOD” FEATURES (continued)
• Haystacks – waves “bouncing” in regular pattern, deep and slow moving water, often at bottom of V’s
Smiling and Frowning Holes
• Frowning holes – tend to keep floating objects in centre
• Smiling holes – easily wash out the sides
Equipment List
• Helmet• P.F.D.• Whistle• Paddle• Wet Suit/Dry Suit• Paddle Top• Boots/Gloves• Water Bottle/Snack• Knife
• Canoe• Spare Paddle• Bailer• Painters• Throw Bag/Rope• Light
Procedures and Signals
• Paddle Signals– Stop, come, go left/right
• Whistle Signals– One blast/three blasts
• Hand Signals– OK, stop, go left/right
Always point in the direction to go!
Dangers - Strainers
• Allows water to pass through but not objects
• Fallen trees, wire fences etc
AVOID!
Dangers – Foot Entrapment
• Foot becomes wedged between rocks
• Force of water knocks swimmer over; prevents him from getting up
DON’T WALK IN MOVING WATER THAT IS MORE THAN KNEE DEEP!
DANGERS – BIG HOLES
• Water pouring over edge re-circulates, holds objects
• Man-made objects particularly dangerous
• “Maytagging”• Try to swim out
AVOID!
Dangers – Canoe Wraps/Pins
• Canoe full of water is equivalent to a small truck
• Can be crushed by pressure of water
When swimming rapids, stay well to the side of canoe!
Proper Swimming Technique
• FEET DOWN STREAM
• BUM UP• FEET UP – fend off
rocks• SCULL with hands• DON’T STAND UP
until the water is less than knee deep
Throw Bag Swimming
• Stay in the “swimming” position
• Hold rope to your chest
• Rope over the shoulder AWAY from the shore
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