Forces of Moving Water
A river's water has energy. Energy is the ability to do work or cause change. Potential energy is the energy that is stored to do work. Kinetic energy is the energy an object has due to it's motion. When gravity pulls water down a slope the water's potential energy changes to kinetic energy. Most sediment washes or falls into a river as a result of mass movement and runoff. Other sediment erodes from a the bottom and sides of a river. Abrasion is the wearing away of rock by grinding action. Load is the amount of sediment that a river carries.
SlopeIf a river's slope increases, the water's speed does too. The amount the river drops toward sea level over a given distance is called a river's slope. If a river's speed increase, it's sediment load and power to erode may increase.
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Volume of Flow The volume of water that moves past a point on the river in a given time is called a river's flow. When more and more water flows through a river it's speed increases. When a river floods, it's power to erode may increase by a hundredfold. A river that is flooding can carry huge amounts of sand, soil, and other sediments.
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Streambed ShapeA streambed's shape affects the amount of friction between the water and the streambed. The force that opposes the motion of one surface as it moves across another surface called friction. Reduced friction allows the river to follow faster. A streambed is often full of boulders and other obstacles. The boulders prevent the water from flowing smoothly. Instead of moving downstream, the water moves every which way in a type of movement called turbulence.Friction and turbulence slow the stream's flow.
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