Geography Reference
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large-scale construction of hydroelectric facilities to help meet the nation's growing energy
demand. The most notable and high-profile project initiated during this period is the Three
Gorges Dam on the middle reaches of the Yangtze River, to date the single most expensive
engineering project in the world.
Hydroelectric dams create electricity by converting the potential energy of water stored
in a reservoir into kinetic energy, then converting that kinetic energy into electrical energy.
Although the technological and engineering aspects of dams are quite complex, the science
is relatively straightforward. Falling water, or water under pressure, is used to spin a tur-
bine, which is connected to a generator that changes the mechanical energy from the spin-
ning turbine into electricity through a coiled copper wire surrounded by a magnet. This
process, called electromagnetic induction, has been understood since the early nineteenth
century. The potential energy of the water impounded behind a dam is a function of the dif-
ference between the surface elevation of the reservoir and the elevation of the river below
the dam, a concept referred to as “hydraulic head.” Rivers with steeper gradients and high
volume thus offer the greatest potential for energy generation.
In his topic Rivers of Empire , which focuses on the arid western regions of the United
States, the historian Donald Worster uses the term empire to denote the processes through
which central authorities extract resources from peripheral regions and allocate them where
they best serve national goals. In the past, this generally meant simply water appropriation:
allocating a precious resource where it was most needed to accomplish national goals.
However, in the case of hydropower development, it is more useful to think of water not
and can be used to fuel economic development in high-demand areas located thousands of
kilometers away.
With rapid economic development, increasing demand for electrical power, and gov-
ernmental support for large public-works projects, dam construction throughout the world
reached its peak in the latter half of the twentieth century. Current figures indicate that
50,000 large dams, which ICOLD defines as those greater than 15 meters in height or hav-
ing a storage capacity greater than 3 million cubic meters, exist in the world today (Scud-
der 2005; WCD 2000). China is home to about half of them (ICOLD 1998). 13 Measured in
installed capacity, the total potential electricity output of hydropower facilities in China is
more than that of Brazil, the United States, and Canada combined (Hennig et al. 2013).
Decisions made within China's hydropower sector—by government agencies and hy-
dropower companies—tend to be technocratic in nature, driven more by engineering and
economics than by broad public engagement. Indeed, technocratic governance seems en-
demic in the higher echelons of political leadership in China. As of 2000, more than half of
all top political posts in China were filled by party members with engineering or technical
college degrees. Li Peng, for example, who held top political posts during the 1980s and
1990s, including terms of service as premier and chairman of the Standing Committee of
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