56
4.2.2 Navigable Waterways
The global navigable waterways encompass a network of 700,000 km that connects
river basins across geographic regions. In the European Union, more than 50,000 km
navigable rivers and canals create a dense web of waterways. Today, you may travel
from southern France to western Siberia without entering the sea. Waterways facilitate the spreading of exotic and invasive organisms, which may lead to a homogenisation of freshwater biodiversity. Plans exist to upgrade and enlarge existing
waterways, such as the Danube-Main-Rhine Waterway, and to create new waterways. At the same time, most of the planned interbasin transfer projects (Table 4.2 )
will support inland navigation too.
In South America, the 3,440 km Parana-Paraguay waterway, called Hidrovia ,
will connect Cáceres (Brazil) with Nueva Palmira (Uruguay). The main aim is to
facilitate the export of soybeans, minerals, timber and other commodities from the
interior. Extensive wetlands, in particular the Pantanal, will be affected by this project (Huszar et al. 1999 ; Gottgens et al. 2001 ). About 7.3 × 10
6 m
3 of sediment are
dredged to enforce and straighten the rivers for navigation and to build ports. The
calculated investment costs for a total of 88 individual projects are estimated at
USD 4 billion ( www.iirsa.org ) .
4.2.3 Hydropower Mega Dams
Currently, at least 161 very large hydropower dams, with a capacity of more than
1,000 MW each, are globally either under construction or planned. For illustration,
a dam of 1,000 MW could, if to 100 % effi ciently working, provide the annual electric consumption for 1.2 million people, assuming the electric consumption per
capita in Germany in 2011 (World Bank 2014 ). This corresponds to suffi cient
energy to fully power a city almost as large and wealthy as Munich (2011: 1.38 million). The total capacity of the future mega dams amounts to 440 GW; most of the
dams are planned in developing countries and emerging economies (Fig. 4.1 ), where
consumption rates per capita are much lower than in Germany.
Not surprisingly, the global distribution of these future dams is not equal (Fig. 4.1 ).
The largest number of large dams will be constructed in the Asian countries of China,
Pakistan and Myanmar, in the South American countries of Brazil and Peru as well as
the African countries of the Democratic Republic of Congo, Ethiopia and Nigeria.
What does this mean for the ecology? The Yangtze basin will be fragmented by
the highest number of hydropower dams in Asia (33 % of the continental total). In
South America, the Amazon basin will receive 61 % of the future hydropower dams
of the continent providing 69 % of the planned capacity. And in Africa, mainly the
Zambesi basin will be confronted with new dams (35 % of continental total) while
the Grand Inga hydropower dam alone and planned in the Congo basin will provide
55 % of the capacity planned in Africa. The Yangtze and the Zambesi basins have
already been classifi ed as heavily fragmented, whereas the Amazon and the Congo
K. Tockner et al.
4.2.2 Navigable Waterways
The global navigable waterways encompass a network of 700,000 km that connects
river basins across geographic regions. In the European Union, more than 50,000 km
navigable rivers and canals create a dense web of waterways. Today, you may travel
from southern France to western Siberia without entering the sea. Waterways facilitate the spreading of exotic and invasive organisms, which may lead to a homogenisation of freshwater biodiversity. Plans exist to upgrade and enlarge existing
waterways, such as the Danube-Main-Rhine Waterway, and to create new waterways. At the same time, most of the planned interbasin transfer projects (Table 4.2 )
will support inland navigation too.
In South America, the 3,440 km Parana-Paraguay waterway, called Hidrovia ,
will connect Cáceres (Brazil) with Nueva Palmira (Uruguay). The main aim is to
facilitate the export of soybeans, minerals, timber and other commodities from the
interior. Extensive wetlands, in particular the Pantanal, will be affected by this project (Huszar et al. 1999 ; Gottgens et al. 2001 ). About 7.3 × 10
6 m
3 of sediment are
dredged to enforce and straighten the rivers for navigation and to build ports. The
calculated investment costs for a total of 88 individual projects are estimated at
USD 4 billion ( www.iirsa.org ) .
4.2.3 Hydropower Mega Dams
Currently, at least 161 very large hydropower dams, with a capacity of more than
1,000 MW each, are globally either under construction or planned. For illustration,
a dam of 1,000 MW could, if to 100 % effi ciently working, provide the annual electric consumption for 1.2 million people, assuming the electric consumption per
capita in Germany in 2011 (World Bank 2014 ). This corresponds to suffi cient
energy to fully power a city almost as large and wealthy as Munich (2011: 1.38 million). The total capacity of the future mega dams amounts to 440 GW; most of the
dams are planned in developing countries and emerging economies (Fig. 4.1 ), where
consumption rates per capita are much lower than in Germany.
Not surprisingly, the global distribution of these future dams is not equal (Fig. 4.1 ).
The largest number of large dams will be constructed in the Asian countries of China,
Pakistan and Myanmar, in the South American countries of Brazil and Peru as well as
the African countries of the Democratic Republic of Congo, Ethiopia and Nigeria.
What does this mean for the ecology? The Yangtze basin will be fragmented by
the highest number of hydropower dams in Asia (33 % of the continental total). In
South America, the Amazon basin will receive 61 % of the future hydropower dams
of the continent providing 69 % of the planned capacity. And in Africa, mainly the
Zambesi basin will be confronted with new dams (35 % of continental total) while
the Grand Inga hydropower dam alone and planned in the Congo basin will provide
55 % of the capacity planned in Africa. The Yangtze and the Zambesi basins have
already been classifi ed as heavily fragmented, whereas the Amazon and the Congo
K. Tockner et al.