Category: 4. Irrigation & Water Supply Engineering

A cofferdam is a temporary barrier that is usually constructed to exclude water from a flooded area. Typically constructed of wood, concrete or steel sheet piles, cofferdams are used to allow the construction of foundations for permanent dams, bridges and similar structures.When the project is completed, the cofferdam may be demolished or removed. Common uses…

Another type of embankment is made with an asphalt concrete core. Such dams are constructed of rock and/or gravel as primary fill. Since the first such dam was completed in 1962, around 100 dams of this design have been built around the world. All asphalt concrete core dams built so far have the best performance…

Earth-fill dams are constructed as a simple embankment of well-compacted earth. A homogeneous rolled-earth dam is entirely constructed of one type of material but may contain a drain layer to collect seep water. A zoned-earth dam has distinct parts or zones of dissimilar material, typically a locally plentiful shell with a watertight clay core.Most modern…

Rock-fill dams are embankments of compacted free-draining granular earth with an impervious zone. The earth used often contains a large proportion of large particles, hence the term rock fill. The impervious zone may be on the top face and made of masonry, concrete, plastic membrane, steel sheet piles, wood or other materials. The impervious zone…

Dams are made of earth and are of two main types, rockfill and earthfill dams. Like concrete gravity dams, embankment dams rely on their own weight to resist the force of the water.

In a gravity dam, stability is secured by making the embankment of such a size and shape that it will resist toe overturning, sliding and crushing. The dam will not overturn provided that the moment around the bend due to water pressure is smaller than the moment due to the weight of the dam. This…

In arch dams, stability is achieved by a combination of arch and gravity action. If the top face is vertical, the entire weight of the dam must be carried by gravity to the foundation, while the normal hydrostatic pressure distribution between the vertical cantilever and the arch action will depend on the stiffness of the…

Masonry dams can be classified into arch dams, gravity dams, embankment dams, rock fill dams, earth fill dams, concrete dams, etc.

Based on the structure and materials used, dams are classified as wooden dams, arch gravity dams, embankment dams or masonry dams with several subtypes.

Desirable purposes include providing water for irrigation to a town or city, improving navigation, providing reservoirs for industrial use, generating hydroelectric power, creating recreational areas or habitat for fish and wildlife,retaining wet season flow to minimize downstream flood risk and containing effluents from industrial sites such as mines or factories. Few dams serve all of…