A
dam is a barrier that
impounds
water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for such activities as
irrigation,
human consumption,
industrial use,
aquaculture, and
navigability.
Hydropower is 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. 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.