Botkin Environmental Science Earth as Living Planet 8th txtbk

378 CHAPTER 18 Water Supply, Use, and Management
FIGURE 18.9 Three images of the Aral Sea from 1977 to 2006. By 2006, the sea had been reduced to
about 10% of its original size. Wetlands around the sea were reduced by 85%; fish species declined 80%,
and birds 50%.
FIGURE 18.10 Ships grounded in the dry seabed as the fishing
industry collapsed.
Transport of Water
In many parts of the world, demands are being made on
rivers to supply water to agricultural and urban areas. This
is not a new trend—ancient civilizations, including the Romans
and Native Americans, constructed canals and aqueducts
to transport water from distant rivers to where it was
needed. In our modern civilization, as in the past, water is
often moved long distances from areas with abundant rainfall
or snow to areas of high use (usually agricultural areas).
For instance, in California, two-thirds of the state’s runoff
occurs north of San Francisco, where there is a surplus of
water. However, two-thirds of the water use in California
occurs south of San Francisco, where there is a deficit. In
recent years, canals of the California Water Project have
moved great quantities of water from the northern to the
southern part of the state, mostly for agricultural uses, but
increasingly for urban uses as well.
On the opposite coast, New York City has imported
water from nearby areas for more than 100 years. Water
use and supply in New York City show a repeating
pattern. Originally, local groundwater, streams, and the