chapter - Atmospheric and Oceanic Science

(chapters 12 and 13), because of the global warming, it cannot be discarded
extremes that will probably overcome all the historical records in the future.
Consequently, designers of the large hydroelectric factories should take into
account Climate Change. They should a priori consider larger margins of safety so
that the dams should have a greater aptitude in order to face floods in a sure manner
and be environmentally compatible. Likewise, the designs for the production of
energy should include the possibility of extreme droughts. It is clear that these
greater safety margins would increase costs, but surely they would reduce both the
socioeconomic and environmental risks, and therefore they would facilitate the viability
of the projects. A more sophisticated alternative is to try to reduce the future
uncertainty by a proper use of climate scenarios and other tools like the ones discussed
in chapters 12 to 15.
c. Dams sedimentation
The World Bank has calculated that, every year, 0.5-1% of the global reservoir
capacity is lost due to sedimentation. This means that 240-480 new dams
should be added every year only to support the global reservoir capacity. The
increasing volume of sediments in a reservoir will eventually either hinder seriously
or hamper completely the functioning of the hydroelectric plant.
There are technologies capable of reducing the level of sedimentation in reservoirs
and dredging the sediments already deposited in the above mentioned reservoirs.
These technologies, anyway, have serious limitations due to different reasons.
They are only good for specific types of dams, are in some cases prohibitively
expensive and eventually reduce the capacity of the dam to generate energy.
A great part of the sediments are transported normally during the periods of
flood. As global warming is being accompanied of a major frequency of large rainfalls,
it is expected a greater intensity and frequency of floods, therefore increasing
the charges of sediments. On the other hand, the changes in the vegetation in the
basin due to the climatic change might complicate the efforts to predict the future
levels of sedimentation.
8.3.4. Fluvial navigation
The main services and problems of water resource
The Paraguay- Paraná fluvial system is a commercial strategic hydro way that
connects the interior of South America with the deep water ports in the low section
of the Paraná River and in the La Plata River. With more than 3300 km length from
its nascent in Cáceres Brazil up to the final end in the La Plata River, the Hydroway
will provide access and will serve as important transport artery for large areas of
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