The Great Flood of 1927 has been called one of the
greatest man-made disasters in the history of this nation.
While it was six months of unusually heavy rainfall that caused the flood, it
was the Army Corps of Engineers' insistence on a "levee only" policy
that many credit with turning a bad flood into an historic disaster.
Since the first Europeans settled along the river, it has always been a problem.
Native Americans told the first European explorers to expect the Mississippi
River to flood every 14 years. A review of the dates of major floods in the
1800s shows they were optimists, with high water coming about every seven years.
Since the earliest settlers, every generation attempted to control the river by
building levees - protective, raised embankments - alongside it.
The first levees were built around New Orleans in the 1700s. But local efforts
were not always effective. It did not take the people living along the river
long to realize they needed a more advanced levee system. For that, they turned
to the federal government.
In 1879, Congress created the Mississippi River Commission to oversee federal
funds for flood control. The Commission was a response to a long-standing
dispute between James Buchanan Eads, an influential civilian engineer on the
Mississippi River, and Andrew Atkinson Humphreys, chief of the U.S. Army Corps
of Engineers, over how best to control the river.
Although the commission was supposed to combine the ideas of both civilian and
military engineers, in practice it was controlled entirely by the corps.
Despite extensive scientific debate over flood control policy, and warnings by
many prominent engineers of the dangers of excessive reliance on levees, over
time the commission solidified its commitment to levees.
In 1885 the commission adopted a "levees only" policy. This policy was
based on the theory that by containing the river with levees, the force of the
high water would scour out the floor of the river, deepening the channel
sufficiently to carry any flood water straight out to the sea.
The use of manmade reservoirs, outlets and cutoffs for runoff were rejected time
and time again. For the next 40 years, the commission stuck to this policy, not
only refusing to build any manmade outlets for flood waters, but also actively
sealing up many of the river's natural outlets.
Martin Reuss, a senior historian with the corps, said before the Great Flood the
corps truly believed the strategy could work. "They believed they could
actually build the levees to a sufficient height to control the river."
But even so, he disputes that the corps was only interested in levees. He points
to extensive dredging projects dating back to the 1890s designed to deepen the
channel and help fight flooding.
Even in those days, he said, the corps was also looking at alternatives,
including a couple of diversion projects, but money got in the way. "The
projects were rejected. They didn't feel it was cost effective - good
engineering but lousy economics."
As with any government agency, money was often a problem. Many times the corps
brought projects to Congress, which refused to fund them.
The more successful the corps got with its levee program, the harder their job
became. Before the great levees were in place, whenever the river would flood,
it would jump its banks, spreading out its water over thousands of acres. By
preventing the flood from escaping the river channel, the water in that channel
kept rising, requiring ever higher and higher levees to contain the flow.
It was a vicious cycle: levees built in 1850 to a height of seven feet had to be
raised to as much as 38 feet - the height of a four-story building.
With each passing year, as the levees grew taller and stronger, so did the force
and volume of the river they fought to contain. And growing right along with the
levees were the dangerous consequences of a break.
When levees did break, as they did in most floods, the corps tended to blame
substandard building techniques. They never questioned the "levees
only" policy.
As late as 1926, the corps, having constructed levees stretching from Cairo,
Ill., to New Orleans, publicly declared that the levee system was now strong
enough to contain the river and prevent any future flooding.
Historian John M. Barry, author of "Rising Tide: The Great Mississippi
Flood of 1927 and How It Changed America," called this boast "classic
hubris."
The Great Flood of 1927 shattered the corps' illusions. The levee system was
decimated with over 120 crevasses or breaks. The crevasses demonstrated that
even the largest and strongest levees alone could not protect the land from
flooding.
The flood of 1927 inundated 27,000 square miles. For two months, the water
remained above flood stage, making almost a million people refugees.
If one has to find a silver lining in this disaster, these crevasses played an
important role in reducing flood levels downstream and are estimated to have
reduced the peak stage at New Orleans by over six feet, saving the city.
In a defense of the corps, John Hill, with the corps' New Orleans office, said
that up until this time, the main concern of the corps had been navigation. The
flood of 1927 would change all that. "It was a big, big change for the
corps. We were in navigation for a long time, then we were in flood
control," Hill said.
Flood control
As a result of the flood, the Flood Control Act of 1928 was enacted giving the
Corps of Engineers responsibility for flood control on the Mississippi River.
A host of new techniques where quickly put into place. Upstream reservoirs were
built on the major tributaries, levees where reconstructed using the most modern
engineering principles and floodways were built to divert flood waters from the
main channel. All these measures were completed before the flood of 1937. The
levees held during that flood even though the river's flow exceeded those of the
flood of 1927.
So, are the days of the great floods over? "No!" was Reuss' emphatic
answer. "I don't think the corps can or ought to play God."
Controlling the Mississippi River is a mind boggling task - what Reuss called
"an enormously complicated hydraulic engineering problem."
The Mississippi has the third largest drainage basin in the world, exceeded in
size only by the watersheds of the Amazon and Congo rivers. Though a series of a
dozen or more rivers, it drains 41 percent of the 48 contiguous states of the
United States from as far east as New York and as far west as Montana.
He argued that every spring there is going to be high water; some years, very
high water. He believes the proper question is can the flood damage be
minimized.
To that question Reuss is more optimistic. He believes with the current theory
can help minimize damage from future floods.
He believes an equally important part of the answer is education. People need to
understand the risks. He said there are certain areas near great rivers that
will from time to time flood. People need to know that and decide if they want
to accept the risks.