"Hydraulic radius = cross sectional area / wetted perimeter.
Hydraulic radius is a measure of the efficiency of the the river channel. The higher the hydraulic radius, the more efficient the river channel is.
The more efficient the river is, the more energy the water will have to
move downstream (so as hydraulic radius increases, velocity increases)
carry load (so as hydraulic radius increases, the river's competence and capacity increases)
increase the rate of erosion (in the upper course, as hydraulic radius increases, there is a higher rate of vertical erosion, so gradient increases; further downstream where the river is closer to base level, as hydraulic radius increases, there is a higher rate of lateral erosion)."
"For many developing countries hungry for energy sources, hydropower is an attractive option. But dams also can place heavy burdens on surrounding populations and eco-systems. While China touts its Three Gorges dam - the world's largest - as environmentally friendly, the United States has begun tearing down a number of its own structures for safety, economic, and environmental reasons. To broaden your knowledge of dams around the world, explore below the economic, environmental, social, and political aspects of five big dam projects in Turkey, Brazil, Laos, Lesotho, and China.
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he Snowy Mountains Scheme has affected the ecology of Snowy Mountain rivers and streams. The Snowy Water Inquiry identified the need to increase flows to the Snowy River below Jindabyne and the Snowy montane rivers.
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