Tuesday, June 28, 2011

Rapids By: Sarah and Kaylee

There are basically two different parts of the river. The rapids and the smooth lazy part; depending on what you're in the mood for, you are sure to have a good time! Everyone has heard of rapids, but what exactly is a rapid? There are four factors which either separately or in combination can create rapids: gradient, constriction, obstruction, and flow rate. Constriction happens when water flow in a river is forced into a narrower channel, the pressure causes the water to flow faster creating rapids.Obstruction is when there is a rock or steep drop in the river bed, then "obstructing" the flow of water. Rapids are a geological phenomenon that occurs when there is a fast moving body of water that is littered with rocks. Since water erodes soft land faster, these hard rocks remain where they are, making incomplete barriers. The rushing water moves around the rocks and often foams into white water. Rapids are also at points of the river where there is a relatively steep gradient, making an increased water flow and turbulence. A rapid forms due to shallowing of the river characterized by rocks exposed above the water surface. We saw most of the rapids when we were in the Lodore and Split Mountain Canyons because that was where the gradient was the highest.
Topography also plays a major factor determining where rapids are formed. It is generally consistent over time. Increased flow that happens during heavy rain fall or flood season can alter the stream bed permanently by depositing rocks in different places or by creating new channels for flowing water. Along the Green River we went along many Rapids. Some of them were: Disaster Falls, Hells Half-Mile, and Triplet Falls. The rapids along the Green River area are classified based on the magnitude of the rapids. The ones we encountered ranged from Class 1-4. If you're in need of a good time, visit the rapids of the Green River in the canyons of the Lodore . You might want to visit during late May and early June, because that is when the best flow is.


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