Tag: Dam

Radiation from Chernobyl
What do the Chernobyl disaster, the Three Gorges dam in China and the spread of the Sahel have in common? In each case natural and manmade influences have forced thousands, sometimes millions of people, to leave their la...
29 Nov 2007 - by Philippe Rekacewicz, UNEP/GRID-Arendal
Ore production and waste generation at Ok Tedi Mine
The Ok Tedi mine is located high in the rain forest covered Star Mountains of Papua New Guinea. Prior to 1981 the local Wopkaimin people lived a subsistence existence in one of the most isolated places on earth. That was...
17 May 2005 - by Philippe Rekacewicz, UNEP/GRID-Arendal
Mercury pollution - transport and cycle
Mines use toxic chemicals including cyanide, mercury, and sulphuric acid, to separate metal from ore. The chemicals used in the processing are generally recycled, however residues may remain in the tailings, which in dev...
17 May 2005 - by Philippe Rekacewicz, UNEP/GRID-Arendal
River fragmentation and flow regulation
This graphic shows the number of new dams that were under construction in 1998. It also indicates the areas which are most affected by river channel fragmentation and flow regulation. River fragmentation is defined as th...
17 May 2005 - by Philippe Rekacewicz, UNEP/GRID-Arendal
Regulation in the Volga river, 1934 compared to 1999
The construction of a large number of dams and industrial facilities on the rivers feeding the Caspian has caused a significant change in the quantity of water inflow. The creation of a succession of large reservoirs, es...
29 Nov 2007 - by Philippe Rekacewicz, UNEP/GRID-Arendal
The inlet of the bay of Kara-Bogaz-Gol before and after the construction of the dam (Turkmenistan, Caspian Sea)
Kara-Bogaz-Gol is a lowland area that forms a highly saline bay on the east side of the Caspian Sea, in Turkmenistan. In Soviet times it was decided to set up a dam to block the flow of saline water from the bay to the C...
29 Nov 2007 - by Philippe Rekacewicz, UNEP/GRID-Arendal
Kara-Bogaz-Gol - restoration of previous water levels after 1992 (Turkmenistan, Caspian Sea)
Kara-Bogaz-Gol is a lowland area that forms a highly saline bay on the east side of the Caspian Sea, in Turkmenistan. In Soviet times it was decided to set up a dam to block the flow of saline water from the bay to the C...
29 Nov 2007 - by Philippe Rekacewicz, UNEP/GRID-Arendal
Water flow from the Caspian Sea to the bay of Kara-Bogaz-Gol, 1930-2000
Kara-Bogaz-Gol is a lowland area that forms a highly saline bay on the east side of the Caspian Sea, in Turkmenistan. Soviet leaders maintained that this was “a useless caldron for evaporation, an insatiable mouth swallo...
07 Nov 2007 - by Philippe Rekacewicz, UNEP/GRID-Arendal
Kara-Bogaz-Gol, desertification while dammed 1980-1992 (Caspian Sea, Turkmenistan)
Kara-Bogaz-Gol is a lowland area that forms a highly saline bay on the east side of the Caspian Sea, in Turkmenistan. In Soviet times it was decided to set up a dam to block the flow of saline water from the bay to the C...
07 Nov 2007 - by Philippe Rekacewicz, UNEP/GRID-Arendal
Industrial hot spots Tisza river basin
On 30 January 2000 a tailings dam at the Aurul Mine in Romania overflowed and released 100,000 cubic metres of effluent containing cyanide into the Tisza River. By the time the overflow was detected, the alarm raised and...
01 Feb 2006 - by Emmanuelle Bournay, UNEP/GRID-Arendal
Formation of lakes and glacier lake outburst floods (GLOFs) by Medvezhi Glacier, Pamirs
The increasing number of glacial and moraine lakes in Central Asian mountains is a matter of great concern. One of the surging glaciers that poses a potential threat is the 15 km long Medvezhi (Bear) Glacier in the Pamir...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Level of river fragmentation and flow regulation
River fragmentation - The interruption of a river’s natural flow by dams, inter-basin transfers or water withdrawal - is an indicator of the degree to which rivers have been modified by man (Ward and Stanford, 1989, and ...
26 Jan 2009 - by Philippe Rekacewicz (Le Monde diplomatique), March 2006
Damming the world
The construction of large dams - defined as those with walls at least 15 metres high - has increased significantly over the past 50 years. The average height of new dams, estimated at 30-34 m from 1940-1990, increased to...
26 Jan 2009 - by Phillippe Rekacewicz, February 2006