|Number of Dams by Country Members|
|Worlds's Highest Dams|
|Classification By Type|
|Classification By Spillway Capacity|
|Classification By Reservoir Capacity|
|Classification By Installed Capacity With Energy|
|Classification By Irrigated Areas|
|Classification By Volume For Flood Protection|
|Classification By Resettled Persons|
The present edition of the Register take into account 39188 dams. Circular letter 1443 specifies the criteria for inclusion. Basic requirement is a structural dam height above foundation not less than 15 metres.
The World Register is widely recognized as the best data basis on dams worldwide. But despite all our efforts, some data are lacking. In using the data basis for calculations, you should stay aware that those calculations are made on the basis of the available data. Therefore, the dams for which the data are lacking are ignored.
Purposes of dams
Runoff waters are a natural resource for nations. For developing countries, storing water is often vital and in any case, the only means to develop economically this natural resource.
Waters reservoirs mainly give them guarantee of water supply for irrigation, domestic and industrial use during droughts and reduce negative impacts of floods.
Number and Purposes of registered dams
39188 Dams data corresponding to registered dams only
Demand for water is steadily increasing and would reach 2-3 per cent per year over the coming decades. With their present aggregate storage of about 16 009 km3, dams clearly make a significant contribution to the efficient management of finite water resources that are unevenly distributed and subject to large seasonal fluctuations. Many more dams need to be built to ensure proper use of this resource, in accordance with ICOLD policy set out in the "Position Paper Dams and Environment".
Referenced dams can be broken in two main categories :
a) single - purpose dams :
The distribution for each purpose lead to the folowing results :
b) multipurposes dams :
The distribution for purposes lead to the following results :
Earth dams predominate for some 62 % of all reported dams. This is of course the oldest type and there are traces or earth dams in the remains of the most ancient civilisations. Furthermore this type of dam can accommodate a wide range of different foundations. The world's second highest dam is Nurek dam in Tajikistan (300 m high).