The purpose of a dam is to retain and store large quantities of water in a safe way. Many considerations are analyzed. Dams can be built anywhere if you can spend enough money. However preferred site have following characteristics which lead to lower project costs. Thus alternate dam sites/axis location are evaluated for most cost effective choice.

Any dam project is carried out in the following stages: 1. Initial screening is conducted based on river profile and topographic maps. 2. Reconnaissance plan is developed using only already available data. 3. Pre-feasibility plan is developed with a little exploration and additional field data. 4. Feasibility plan is developed with

Dams and reservoirs are built to raise water level for storage and safe retention of large quantity of water. Water is subsequently released to achieve various purposes. Dams may be constructed to meet one or more purposes as: Irrigation, Hydropower development (Tarbela Dam, Mangla Dam), Domestic, municipal, industrial water

El Cajón dam, Mexico, has a 188 m high concrete-face rockfill dam. The El Cajón Dam is a hydroelectric dam on the Río Grande de Santiago in the Mexican state of Nayarit. Construction began in 2003 and was completed in June 2007. It cost US$800 million to build. It is 640 m (2,100 ft) long and is 178 m (584 ft) high. The reservoir

It is one of the most extreme engineering projects in World History, to build a 35 miles long tunnel under the Alps Mountains. It is the longest tunnel in the world. This could not be possible without world’s strongest drilling machines, each more than 3 stories high and longer than 4 football fields, drilling 24hrs a day for 6 years. The project costed $7 Billion.