A dam is a barrier across the flowing stream that obstructs, directs or disrupts the flow of the river, often creating a reservoir, lake or impoundment. A ‘dam’ means a reservoir rather than the structure.
Dams are classified according to :
(i) Based on the structure and the materials used, dams are classified as :
(a) Timber dams.
(b) Embankment dams.
(c) Masonry dams.
(ii) According to height, dams can be categorized as :
(a) Large dams.
(b) Major dams.
(c) Low dams.
(d) Medium height dams.
(e) High dams.
Problems caused due to multipurpose projects are:
(i) The dams that were constructed to control floods, have triggered floods due to sedimentation in the reservoirs.
(ii) Release of water from dams during heavy rains aggravated the flood situation in Maharashtra and Gujarat in 2006.
(iii) The floods have caused extensive soil erosion.
(iv) Multipurpose projects induced earthquakes caused water-borne diseases and pests and pollution.