Hydropower is essentially a product of solar energy. The sun begins the hydrologic cycle by evaporating water from land and sea. Hot air, which rises over the water, carries moisture to the land as rain or snow. Much of the water falls on high lands and drains into streams and rivers as it flows back down to the sea. This flow over the different elevations can be harnessed by a hydroelectric project to produce electricity. Hydroelectric generation is the cleanest source of electrical energy available and is a renewable resource since the natural flow of water is a continuous process. It...