Laboratory Manual for Introductory Geology 4e

13.9 Streams, Society, and the Environment
Streams have been a vital natural resource since the beginnings of human society,
serving as a source of water and food, as avenues for exploration and transportation,
and as political boundaries. From medieval times, streams drove the water
wheels that provided the energy for mills to grind grain into flour and cut trees into
lumber, and eventually, the more sophisticated versions that powered the Industrial
Revolution in the 1700s. Today, streams contribute to power generation directly, by
turning turbines that generate hydroelectricity, and indirectly, by cooling nuclear
reactors. But building dams and diverting water for industrial cooling interfere
with natural stream processes, and pollutants have all too frequently had disastrous
effects on fish and other stream dwellers (FIG. 13.25).
FIGURE 13.25 When streams are polluted.
(a) Before (left) and after (right) the 2015 Gold King Mine
wastewater spill in Colorado.
(b) The heavily polluted Calumet River near Chicago.
EXERCISE 13.10
Unforeseen Consequences of Human Interaction: Aswan Dam
Name:
Course:
?
What Do You Think Unintended
or unforeseen consequences
of human interactions with streams can cause serious problems
for human and wildlife communities. Consider the Aswan High Dam, which
was built across the Nile River in the 1960s to generate electricity for Egypt, a
nation lacking oil and gas resources. The dam created an enormous lake (Lake
Nasser) upstream. As is the case with every dam, the lake acts as a local base
level for the Nile. The dam also diverts about 55 trillion liters of freshwater
for irrigation and hydroelectric power generation every year, preventing that
water from reaching the Mediterranean Sea, into which the Nile drains.
For thousands of years, annual spring floods replenished fertile soil in the
floodplain of the Nile. The Aswan High Dam prevents these floods.
Section:
Date:
Mediterranean
Sea
Alexandria
On a separate sheet of paper, describe the positive and negative effects you think the dam might have had
on Egyptian agriculture. In addition, describe the effects the dam might have had on aquatic organisms in the
Mediterranean Sea.
Aswan
Dam
Egypt
Jerusalem Jordan
Israel
Cairo
Lake
Nasser
13.9 STREAMS, SOCIETY, AND THE ENVIRONMENT
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