Environmental Engineering Reference
In-Depth Information
the National People's Congress was unprecedented. The World Bank would
not support it due to its environmental damage and poor cost-benefit ratio.
Located in Hubei Province as the Yangtze River comes out of the moun-
tains onto the plain west of Wuhan, the dam is 185 meters high and
2.3  kilometers across, and its reservoir extends upstream 660 kilome-
ters to Chongqing. Its electric generating capacity will eventually reach
22.5  gigawatts. The dam aids navigation and control floods. Its cost is
$30 billion. At present its capacity exceeds the electricity demand in the
region, and the distribution system is inadequate. Environmental damage
is extensive. Prior to the dam, the scenery was spectacular as the huge
river rushed through the narrow gorge for hundreds of kilometers. Spring
floods poured torrents into the river, causing it to rise greatly and flow
dangerously fast. High mountains line both sides. Numerous tributaries
flow in from even narrower gorges. Monkeys and mountain goats can be
spotted on the cliffs. The dam has displaced 1.3 million people in 13 cities
and 140 towns. It has submerged ancient temples and archaeological sites.
Silt filling the reservoir behind the dam threatens to diminish its holding
capacity and change the river downstream. Warmer water temperatures
endanger fish. The weight of the water threatens earthquakes.
Until the 1950s, boats could only sail upstream against the fast current
by being pulled by human labor hauling towropes. Teams of dozens and
even hundreds of men would strain against the lines with all their might,
bending in their harnesses nearly to the ground along narrow footpaths
chipped into the rocks along the gorges. Their subhuman labor symbol-
ized all the poverty and depravity of ancient China. Peasants were desper-
ate to earn a few coins. The naked laborers were whipped, while drums
beat to keep them pulling in rhythm. Each man wore a special harness that
revealed to the overseer whenever he was not pulling his weight. Sailing
boats downstream was less laborious but more dangerous. Treacherous
currents and hidden rocks often capsized boats or ripped holes in their
hulls. In recent years stronger marine engines eliminated the need for
human labor, and dynamite has blasted away most underwater rocks.
Upstream, where the Yangtze is known as the Jinsha River, China
plans to build 12 more dams. The upper reaches of the Jinsha are particu-
larly desirable for hydroelectricity because the river falls steeply, nearly
3 meters per kilometer. In these remote mountains, the gorges are deeper
and more numerous than the Three Gorges. In the Tiger Leaping Gorge,
steep cliffs rise 2000 meters on each side. Collectively, the dams would
generate 60 gigawatts of electricity, control floods, and reduce siltation
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