Botkin Environmental Science Earth as Living Planet 8th txtbk

42 CHAPTER 3 The Big Picture: Systems of Change
CASE STUDY
Trying to Control Flooding of the Wild
Missouri River
The Missouri River drains one-sixth of the United States
(excluding Alaska and Hawaii) and flows for more than
3,200 km (2,000 miles). After the land along the Missouri
was settled by Europeans, and after large towns and cities
were built on the land near the river, flooding of the
Missouri became a major problem. The “wild Missouri”
became famous in history and folklore for its great fluctuations,
its flows and droughts, and as the epitome of unpredictability
in nature. One settler said that the Missouri
“makes farming as fascinating as gambling. You never
know whether you are going to harvest corn or catfish.” 1,2
Two of the river’s great floods were in 1927 and 1993
(Figure 3.1). After the 1927 flood, the federal government
commissioned the Army Corps of Engineers to build six
major dams on the river (Figure 3.2). (The attempt to
control the river’s flow also included many other alterations
of the river, such as straightening the channel and
building levees.) Of the six dams, the three largest were
built upstream, and each of their reservoirs was supposed
to hold the equivalent of an entire year’s average flow. The
three smaller, downstream dams were meant to serve as
safety valves to control the flow more precisely.
The underlying idea was to view the Missouri as a
large plumbing system that needed management. When
rainfall was sparse in the huge watershed of the river, the
three upstream dams were supposed to be able to augment
FIGURE 3.1 St. Louis, Missouri, during the 1993 flood of the
Missouri River. No matter how hard we try to keep this huge river
flowing at a fixed rate, neither flooding nor in drought, we always
seem to fail. So it is when we try to tame most natural ecological
and environmental systems that are naturally dynamic and always
changing.
FIGURE 3.2 The six major dams on the Missouri River. (Based
on drawing by Gary Pound from Daniel B. Botkin, Passage of
Discovery: The American Rivers Guide to the Missouri River of
Lewis and Clark [New York: Perigee Books, a division of Penguin-
Putnam, 1999].)
the flow for up to three years, ensuring a constant and adequate
supply of water for irrigation and personal use. In
flood years, the six dams were supposed to be able to store
the dangerous flow, so that the water could be released
slowly, the floods controlled, and the flow once again
constant. In addition, levees—narrow ridges of higher
ground—were built along the river and into it to protect
the settled land along the river from floodwaters not otherwise
contained. But these idealistic plans did not stop
the Missouri from flooding in 1993 (Figures 3.1 and 3.3).
Taking the large view, standing way back from the
river, this perception of the Missouri River was akin to
thinking about it as one huge lake (Figure 3.4) into which
water flowed, then drained downstream and out at its
mouth at St. Louis, Missouri, into the Mississippi, which
carried the waters to New Orleans, Louisiana, and out into
the Gulf of Mexico. The hope was that the Missouri River
could be managed the way we manage our bathwater—
keeping it at a constant level by always matching the outflow
down the drain with inflow from the spigot. This is
a perception of the river as a system held in steady state, a
term we will define shortly.
Before there were permanent settlements along the
river—both by American Indians and by Europeans—
the Missouri’s flooding didn’t matter. Nomadic peoples
could move away from the river when it flooded during
the rainy seasons, and wildlife and vegetation generally
benefited from the variations in water flow, as will be explained
in later chapters. Only with modern civilization