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The practice of damming rivers to create reservoirs has a
long history, with examples dating back to Roman times. Over the years, the
reasons for damming rivers have evolved, with three main purposes being
human consumption, irrigation, and industrial use. However, while damming
rivers provides many benefits, it also causes significant problems,
especially in underdeveloped countries.
One of the primary advantages of damming rivers is to provide a reliable
water source during droughts. Rainfall is never uniform enough to provide a
steady flow of water, but reservoirs can hold water for extended periods,
which can be used during dry weather. Dams also help control the flow of
floodwater in mountainous areas, which can destroy crops, homes, and animal
and human life. Dams can also retain large quantities of water for
controlled use, working from sea to river and vice versa.
Another significant advantage of damming rivers is the production of
hydroelectric power. By channeling water through conduits and using it as
mechanical power for turbines, dams can produce vast amounts of energy. The
reservoir water is also used in nuclear power stations for cooling and other
purposes, with the water being returned to the river or sea afterward. Dams
can also provide a constant depth for rivers, making them navigable by large
vessels and benefiting a country's communication system.
In many cases, a dam is part of a multipurpose scheme that encompasses
several functions, such as irrigation and power production. This is
particularly true in temperate zones, where water shortage is a minor
inconvenience rather than a disaster. However, in underdeveloped countries,
which are hot, dry, and barren, the situation is entirely different.
Populations in these areas are often nomadic, driving flocks and herds from
waterhole to waterhole or scratching a subsistence from the soil. Droughts
mean disease, hunger, dehydration, and death to animals and humans alike.
Damming major rivers like the Nile is crucial to life itself, with the
control of their floodwater for irrigation purposes being essential.
However, even this does not prevent large tracts of North East Africa from
reverting to desert.
On the downside, damming a river can cause significant problems. A great
area of land, with its trees, flora and fauna, farms, and houses, has to be
inundated. Neither the residents who have to resettle elsewhere nor
environmentalists appreciate this. The problem is more acute when the
countryside being spoilt is environmentally unique. Creating an artificial
lake inevitably changes the character of a large area, with farmland
destroyed, and natural scenery despoiled, in some people's opinion. People
also have to move, which can be inconvenient.
Another drawback of damming rivers can be political. Many rivers flow
through more than one country, with the country lying higher up the river
having the upper hand. A dam built for one country's benefit may be much to
the detriment of another. The USSR has been in dispute with Turkey over this
matter, as has Egypt with the Sudan.
Lastly, dams are vulnerable to air attacks in wartime. The destruction of
the Mohne See dam in World War II brought the Ruhr's industry to a
standstill, resulting in the loss of life. Dams can also collapse due to
inadequate strength and imperfect design, with disastrous consequences. |
