Environmental Engineering Reference
In-Depth Information
world. It is reducing air pollution and carbon dioxide emissions from fossil fuel combustion (mainly coal) and
will also diminish China's reliance on imported energy. Commerce ships and commercial fishing boats can
travel a considerable distance along the river. Seasonal flooding downstream has been lessened as well, while
water available for irrigation for land below the dam has increased.
The controversy over the building of the Three Gorges Dam will continue well into the future, as there are no
definitive answers and the pros and cons are both valid.
California Water Project
With the growth of Southern California, especially including Los Angeles and San Diego, the demand for
freshwater in the region has increased dramatically. Since Southern California is in an arid and semiarid cli-
mate without a large natural freshwater source, a water diversion project was constructed, diverting water from
other parts of California to meet the needs for Los Angeles and the rest of the Southland. A huge network of
aqueducts, pipelines, pumps, and dams was built to transfer water from northern and eastern California and
Arizona to Southern California. Starting in 1916, water was diverted from the Owens River Valley and then
from the Colorado River. Then in 1941, due to a continually expanding population, a new aqueduct was added
to the Owens Aqueduct, bringing water from Mono Basin north of the Owens Valley. In the 1950s, the aque-
duct was expanded once again to access water from Northern California.
The massive diversion and consumption of water from these regions has had a devastating impact on the local
ecosystems, including the drying of Owens Lake and subsequent desertification of much of the Owens Valley.
Lack of water traditionally used for agriculture sparked anger and violence from local farmers, and resulted in
the farmers sabotaging part of the aqueduct in 1924. Los Angeles was taking their water and destroying their
lives and their livelihood. Farmers' concerns failed to stop water diversion; in fact, even more was taken, as
groundwater was eventually also pumped to feed the aqueduct.
The Mono Basin experienced a similar fate. Water from the creeks that fed Mono Lake was diverted to the
aqueduct, thus reducing water flow into the lake. The water level dropped and became more saline and alkaline
(basic). This change in the water led to dramatic ecosystem alteration in and around Mono Lake. For example,
brine shrimp populations declined and migratory bird populations left the area. Because of the drop in water
level, a land bridge was exposed, making the eggs of some nesting birds easy food for some predators, impact-
ing the birth rate of species such as the gull.
In 1994, pointing to the devastation of the Mono Basin, the Audubon Society and the Mono Lake Committee
(among other concerned groups), were able to gain protection for Mono Lake and its streams. The water level
has since risen and the potential for drought and desertification were avoided.
However, the Owens Valley and Owens Lake were slower to gain protection. After extensive court battles and
litigation between the city of Los Angeles and the Owens Valley, in 2006 courts ordered that some water be re-
turned to the Valley. The river is now flowing and the aquatic ecosystem and the land along its banks is return-
ing to life, slowly.
Human
China: One-Child Policy
In 1979, China was experiencing food shortages and famine, so it instituted a "one-child" policy to reduce
stress on the food supply. This policy required that people of the ethnic Han majority in China have only one
