Geoscience Reference
In-Depth Information
Chapter 5
Tamed rivers
The servitude of rivers is the noblest and most important victory which man has ob-
tained over the licentiousness of nature.
Edward Gibbon (1737-94)
(English historian)
People have interacted with rivers throughout human history and their impacts, both dir-
ect and indirect, have taken many forms. The earliest examples of water being extracted
from rivers on a significant scale for the irrigation of crops date back 6,000 years. Deliberate
manipulation of river channels through engineering works, including dam construction, di-
version, channelization, and culverting, also has a long history. Some of the world's oldest
dams, in the Middle East, were built more than 4,500 years ago and deliberate diversion and
regulation of the Yellow River in China, for example, began more than 2,000 years before
the present. Since these early examples, the deliberate human alteration of rivers all over the
world has expanded in its extent and escalated in its ambition and scale. Nevertheless, sig-
nificant geographical differences in the degree and intensity of river modifications remain.
In Europe today, almost 80% of the total discharge of the continent's major rivers is affec-
ted by measures designed to regulate flow, whether for drinking water supply, hydroelectric
power generation, flood control, or any other reason. The proportion in individual countries
is higher still. About 90% of rivers in the UK are regulated as a result of these activities,
while in the Netherlands this percentage is close to 100. By contrast, some of the largest
rivers on other continents, including the Amazon and the Congo, are hardly manipulated at
all.
