CLASSIFICATION OF DAM

Dams can be classified in number of ways. But most usual way of classification of dam are mentioned below-

Based on Structural Behavior-

• Gravity Dam- These are the dam which resist the horizontal thrust of water entirely by their own weight.
• Arch Dam- These are designed so that the force of water against it known as hydro-static pressure presses against the arch compressing and strengthening the structure as it pushes into its foundation or abutment.
• Buttress Dam- A buttress dam or hollow dam is a dam with a solid water tight upstream side that is supported at intervals on the downstream side by a series of buttress or support.
• Embankment Dam- These are typically created by the placement and compaction of a complex semi plastic mound of various compositions of soil, sand, clay and rock

Based on Function of Dam-

• Storage Dam- They are constructed to store water during the rainy season when there is a large flow in the river.
• Detention Dam- Detention dam are constructed for flood control. A detention dam retards the flow in the river on its downstream during floods by storing some flood water. 
• Diversion Dam- A diversion is constructed for the purpose of diverting water of the river in to an off taking canal.
• Debris Dam- A debris dam is constructed to retain debris such as sand, gravel and drift wood flowing tin the river with water.
• Coffer Dam- It is an enclosure constructed around the construction site to exclude water so that the construction can be done in dry. 

Based on Material Used-

• Rigid Dam- These types of dams are those which are constructed of rigid materials like masonry, concrete, steel, timber etc.

1. Masonry Dam- These are made out of masonry mainly stone and brick sometimes joined with mortar.
2. Steel Dam-  A steel dam consist of a steel frame work with a steel skin plate on its upstream face.
3. Timber Dam- Main load carrying structural element of timber dam are made of wood primarily coniferous varieties such as pine and fir. 

• Non Rigid Dam- These types of dam are constructed with non rigid material such as earth, tailings, rockfill, rubber fabric etc.

1. Rubber Dam- These dams are made by using huge cylindrical that are made of synthetic rubber. They are inflated using either compressed air and pressurized water.
2. Earthen Dam- An earth dam made of earth built up by compacting successive layer of earth using the most impervious materials to form a core and placing more permeable substance on the upstream and downstream sides
3. Rock fill Dam- A Rock fill dam is built of rock fragments and boulders of large size. An impervious membrane is placed on the rock fill on the upstream side to reduce the seepage through the dam.  

Based on Hydraulic Design-

• Over flow Dam- A dam designed for raising the water level of rivers or for creating a reservoir, it permits the overflow of water during the passage of excess discharge over the entire length of the dam crest or through drain opening.    
• Non Over Flow Dam- Non over flow dams are those which are not designed to be over topped. This type of design giver wider choice of materials including earth fill and rock fill dam.