A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees(also known as dikes) are used to manage or prevent water flow into specific land regions.Hydropower and pumped-storage hydroelectricity are often used in conjunction with dams to generate electricity. A dam can also be used to collect water or for storage of water which can be evenly distributed between locations.

Classification and Types of dams

Classification of dams on the basis of materials used in dam construction

1. Rigid Dams (Concrete dams, steel dams, timber dams etc)
2. Non-Rigid dams (Beam Design Formulas , rockfill dams)

Classification of dam types with respect to size/height of the dam

1. Low dam / Small dam (How to build small dams)
2. Medium dams
3. High dam / Large dams

Classification of dam according to its purpose/use

1. Water supply dam/Irrigation dams
2. Power dams
3. Multipurpose dams
4. Flood control dams