Reservoirs & Ponds
The largest and most common type of reservoir is called a valley dammed reservoir. Some of the most important uses of reservoirs here in North America are to control water flow, irrigation, and flood prevention. Another major use of reservoirs is for a dam. Hydroelectricity is one of the world’s major sources of electric power.
To construct a valley dammed reservoir, the river must be diverted. Construction of the dam itself can then begin right in the old river bed. Once finished, the diversion is removed and the river freely flows gradually filling the reservoir.
Dam use reservoirs where changing water levels can adjust the amount of energy generated. When demand is low for instance, water is held in the reservoir and water levels are higher. When the water is released it spins a turbine at a controlled rate creating Hydroelectricity.