why did river water dinamic?

Answer 1

Why do you want to read this paper?

It’s plain, if you want to river raft, then you have to understand the dynamics of the element with which your corresponding. Water is a simple creature. It officially starts with just three pieces, two hydrogen and an oxygen. A billion times a billion of these constructions make a river. We have to respect the power of these tiny connections when we ride their backs over a bed of rocks. And by respect, I mean give them all our attention.

Water, unlike people, does not make errors. The river is omniscient, and we as river rafters struggle to meet its high standard of performance. If read incorrectly, the river judges us. The punishments are swift, equal to the severity of our mistake and the forces in play. The river is impartial to our intentions, our pleas and any importance we may think we have. These things don’t matter to a river, and so when we are river rafting, they don’t matter period.

Since water does not second guess itself river rafters don’t have time to make second guesses either. If we are to enjoy river rafting, we must be prepared. Preparation comes from studying the river’s features, learning its characteristics, the danger they pose and what to do when we encounter them. Water is Zen-like in that it just acts. The rewarding part of river rafting comes when, sometimes, you do the same and just act.

Eddies, Hydraulics and Strainers/Sieves

There are many different kinds of river features, each have their own unique personality and conditions. The river features this paper touches on are: eddies, hydraulics, and sieves/strainers.



Eddies

Eddies are a rapid’s rest stop, calm pools which exist in the middle of flowing water. If you’ve never seen an eddy, it may be difficult to understand how there could be calm pools in a raging rapid. The best way understand an eddy is to go find one and study it. However, if you don’t want to travel or you live in Florida then you’ll have to settle for a second hand description.

Water usually flows down hill. Eddies are the exception. When water flowing downstream hits an obstruction it can’t move or go over, the water goes around. The water speeds by the obstruction, leaving an empty space behind it. This empty space must be filled so some water makes a u-turn and flows upriver or uphill to fill the empty space. It sort of looks like the river’s current is curling around the obstruction. The result is a small, relatively calm pool lapping the back of the obstruction. This we call an eddy. Our main concern as river rafters is to be able to maneuver in and out of eddies without losing control.

There is a physical border between the eddy and main current. This border is called the eddy line. It’s a tenuous place to be, because you get pulled in two directions at once, both downriver by the adjacent current and upriver by the curling eddy. This means that crossing an eddy line (to leave or enter an eddy) can be tricky, because no matter which direction you are going the water wants to go the other.

Entering an eddy from the main current, boats slow down. The loss of velocity can occur quickly. Just like when you step on the breaks of your car, entering an eddy cause you to jolt forward. Thus, in really fast water entering an eddy with your boat can feel like driving a car off the interstate into a brick wall. However unlike a car, which contains seatbelts, a boat will throw its passengers very easily. This means that if you are not well braced into your raft, you will be flung out of into the water or, OUCH!, onto a rock.

There is a maneuver to enter an eddy and reduce the jolt effect. Rather than hit the eddy head on, we catch a piece of the boat’s bow or stern on the eddy line. This part the boat locks into the eddy while the rest of the craft swings around, gracefully pivoting into the eddy like a door on a hinge. With this maneuver mastered, one can catch an eddy in the middle of a forceful rapid to take a break, scout the rapid or help a rafter in distress.

Exiting an eddy is very simple. Simply hang part of your craft in the main current outside the confines of the eddy. The current will catch the boat, drag it out of the eddy and downriver. However if you are not well braced into the raft, the jolt from speeding up suddenly may pull you backward out of the boat.





Hydraulics

Hydraulics are basically a sideways whirlpools. You can envision them as a wheel of water, the hub at the waterline. Half the heel turns above water and half turns below. Above the surface a hydraulic may take on many appearances, as a wave or foam pile. Below water they all have the same dynamic, re-circulation. The point where surface water surges below the river is informally call the mouth. The mouth of a hydraulic can pull people and boats underwater if its surging is powerful enough. It is precisely this ability which make hydraulics dangerous.

A hydraulic forms when water runs over the top of a rock or off a ledge. The water is going over the rock with such force that it shoots below the surface. This water generally looks like a smooth glassy wall that disappears into foam. Eventually the driving water loses force and returns to the surface a little bit downstream from where it entered. Just like with an eddy, there is empty space that the water curls upriver to fill. Picture an arm flexing at its bicep. The arm is the path of the water. Coming over the ledge (the shoulder) the water surges down (to the elbow), where it ascends to the surface (the forearm) and fills back upstream (the fist).

Of course the water is moving quickly so that a hydraulic looks dynamic, and perhaps more impressive than your flexed arm.

Sometimes hydraulics will have the added danger of being shallow. This means there is a rock at the bottom (the elbow) of the hydraulic. When people get sucked into a shallow hydraulic they hit this rock, and if the hydraulic is powerful enough to recirculate, they continue hit the rock every time they complete hydraulic’s cycle. Thus, if you are re-circulated three times then you get smashed up against this submerged rock three times. Not a pleasant experience really.

Deep hydraulics not powerful enough to recirculate a person are generally safe and fun. A popular activity is ride or surf such hydraulics. Since they form foam piles, much like those of waves at the beach, hydraulics can be surfed by boats just as waves are surfed at the beach. The hydraulic must be strong enough to hold your boat otherwise you’ll just float downstream. Thus, there is a perfect moderation at which a hydraulic is strong enough to surf but not so strong that it will recirculate you if you fall in.

If you ever find yourself caught in a powerful hydraulic, the advice of authorities (those who have been re-circulated) is to swim or sink to the hydraulic’s bottom where there is a strong under-current that will flush you out. Theoretically this exit exists in every hydraulic, like the **** hole of the hydraulic animal. However, there is a label for hydraulics which do not seem to have such exits. These are called keepers, and they cannot be reckoned with from inside. Their system can only be fought from the outside, namely by a sudden decrease in water flow (that is to say a miracle happens and the river dries up) or some handy person throws you a rope and pulls you out. There’s something unsettling about the idea of getting sucked into a hydraulic, pulled under water, then thrown up against a foam pile, which serves you yet again to the churning mouth of the hydraulic. Its like groundhog day every five seconds, where instead of repeating what you did the day before, the last five seconds of your life is in an infinite loop of punishment. But don’t be too afraid of hydraulics, otherwise you’ll avoid them and miss out on all the great surfingJ.



Sieves and Strainers

Sieves and strainers are technically different river features, however their effect is similar. The danger of sieves and strainers for us is the same. When water goes through a strainer or sieve it flows through smaller-than-person-sized spaces. Where water flows relatively unhindered, large solid objects (such as us and our equipment) cannot. Strainers are usually made out of wood or some debris on river transit, temporarily clogging a narrow channel. Sieves on the other hand are usually made out of stable rock piles, broken down with many cracks for water to pass through.

While sieves pose a constant danger, their danger is more predictable because they don’t change much. Because we know where sieves are located, we can be prepared to avoid them. Sieves are such permanent fixtures on a river that they get names like, ‘crack in the rock’ and ‘death trap’. They become marked areas of a rapid, a no man’s land where we don’t go on purpose. Strainers, on the other hand, are usually more dynamic than sieves. That is, they change over time. Strainers can form and disappear over night, dissolving into jetsam that floats downriver. Other times strainers can pick up more debris, growing in size. They can also become dislodged and float downstream until they get caught in another tight spot. When strainers travel, the river becomes twice as dangerous because you have to watch your back for debris as well the rapid that’s in front of you. Usually such debris (including uprooted trees, barrels, pumpkins and whatever else the river can grab) only occur at higher than normal water flows, when the river has flooded over its banks and has access to all kinds of stuff that is normally out of reach.

Because the river is powerful, too powerful to fight really, we usually like to ‘go with the flow’. That is, to work with the river instead of against it, using its currents to take us where we want to go rather than fight against the force of its current. However when there is a sieve or strainer, allowing one’s self to go with the flow might ultimately lead to a desperate fight against the river. Desperate fights against a river usually result in what one might call ‘a religions experience’ (tunnel of light stuff). Interesting I’m sure, but not what I would call a successful river trip. Therefore, wherever there is a sieve or strainer we do not stray or even approach. The philosophy rationalizing this conduct is that the further one is from a dangerous thing, the further they are from harm. For example, imagine if you see a rapid raccoon foaming at the mouth. You wouldn’t go up to pet it, feed it, or get a better look at its fevered eyes. No, you would stay the hell away. Well, that’s just what you should do with regard to sieves and strainers. Stay the hell away.

What have you learned?

Hopefully you’ve learned that the river is a dangerous place. Maybe you were planning to attend a half-assed trip with a couple of buddies, who claimed to ‘know what they’re doing’ but have now decided to postpone for some more research. Great idea! By the way, this paper is not research. It’s more like a rough sketch of the river. There are many more things you need to know about river rafting. To learn more take a swift water rescue class, purchase a trip by a professional rafting company, and get in contact with your local river enthusiasts. There are many sources out there to educate you in river safety. Learn from others and hopefully you’ll have fewer of your own mistakes.


not shore if this will help you!

Answer 2

If you mean "Why is river water dynamic?" there are two possible answers depending on your definition of dynamic.

It is dynamic because it is in motion (seeking sea level)

and

It is dynamic because it can be used to generate electricity, run machinery or do work. This is done by using the water to turn turbines in electric generators.

A WATER POWERED FACTORY:

1. Water is used to a turn a water wheel. (If the axle of the wheel runs through the entire factory, go to # 4.)

2. The wheel is connected to belts or gears.

3. These belts or gears turn a shaft which runs all the way through factory building.

4. The shaft (or axle) is connected to several other belts or gears throughout the factory.

5. The other belts or gears are connected to machinery or other shafts (if they are connected to other shafts -- go back to # 4.)

The river water is thus used to run machinery in factories.

The current of the river is sometimes used to push the water wheel from the bottom...
but GRAVITY is a much more reliable (and constant) way to do it. Gravity is used by releasing the water at the top of the wheel and letting the weight of the water turn the wheel.

That is why you find so many old factories located next to a waterfall or on the slope of a hill.
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Answer 3

To get to the other side.