A small dam can have a big
The three main reasons for building a large dam are:
1) Rain storage for agriculture and domestic water. Seasonal, and often irregular or
undependable rans are stored and released gradually to supply farming and public needs.
2) Electricity Generation - it was possible to know the temperature in
Phoenix by the river's level or volume below Lake Powell or Glen Canyon dam, because the hotter it was in Phoenix,
the more electricity was needed for millions of air conditioners, forcing the dam to release more water to generate
3) Recreation: boating, swimming, fishing, camping, etc.
Small dams, however, are often built to store water for other reasons:
1) To maintain ground water level. The lake or pond which is held behind the dam gradually
releases water into the ground, raising the water table and perhaps helping trees and other vegetation whose roots
may otherwise be left high and dry by dropping water levels.
2) To attract wildlife. Water is a magnet and can draw animals from miles away by its
smell and can bring birds down by its reflection.
3) To put out fires. A large body of standing water, coupled with a capable pump, provides
some defense against fires. If the stored water is 15 feet above the fire, no pump may be necessary, only a
4) Backup water supply.