“Forget reservoirs, how can they work if already
filled with water...” mutters 35-year-old Arthur E. Morgan, biting on a pencil.
It is September 1913, nearly six months
after the worst flood in Ohio’s history had wreaked death and destruction on
Dayton and other cities along the Miami River. His presentation of
flood-protection options to the Dayton Citizens’ Relief Commission is just
weeks away. And the Commission—which had wanted to see dirt flying by fall—is getting
impatient at the time the Morgan Engineering Company is taking to figure out a
solution.
 |
| Arthur E. Morgan’s diagram of the flood control dams of the Miami Conservancy District shows their squat, triangular cross section, massive enough to hold back a volume of floodwaters 40 percent greater than that of March 1913. At the base of each dam would be conduits or culverts forming a principal spillway left permanently open, big enough to allow each river to flow through unimpeded, even during normal spring freshets. But the conduits or spillway would be proportioned to hold back or retard any flow greater than what the riverbeds below could safely handle. [Credit: Arthur E. Morgan, The Miami Conservancy District, page 249] |
Spread on the desk before Morgan are engineering sketches for eight possible flood-protection projects. They range from massive local levees through Dayton, to diverting whole rivers around the city, to enlarging and straightening river channels, to several reservoir systems of differing designs.
All are huge projects. All are expensive.
And none meets Morgan’s stringent goal.
“What can last not just fifty or a hundred
years, but will endure for all time...?” he wonders aloud, trailing off.
For the thousandth time, he scrutinizes a
topographic map of the rolling Miami River watershed, making up 10 percent of
the state of Ohio. In his mind’s eye, he clearly sees how the Miami Valley
acted as a mammoth funnel, directing the phenomenal volume of water from
unprecedented rainfall over the entire valley straight into downtown Dayton and
other cities.
But almost as if for the first time, Morgan
also focuses on how the individual valleys of the Miami River and its four principal
tributaries—the Mad River, the Stillwater River, Twin Creek, and Loramie Creek—alternately
widen and narrow.
Suddenly an amazing idea strikes him.
What if big earthen dams were strategically
placed at the lowest narrow neck of each of five valleys? But instead of creating
reservoirs filled with water for drinking, irrigation, or recreation, what if
at the base of each earthen dam permanently open outlets or conduits let each
river flow through the dam unimpeded? If the rivers swell with a major flood,
the hulking dams would hold back the excess floodwaters, their open conduits
letting through only a flow that could be safely handled by the river channels
below. Never again would Dayton and the other cities be assaulted by flood—and
all with absolute reliability: there would be no gates to open or close—no
moving parts to fail!
Morgan begins scribbling numbers on a sheet
of graph paper, and can’t believe his eyes at the result. He calculates again.
Same answer.
He knows what he’s going to say.
On October 3, 1913, Morgan stands
before the Dayton Citizens’ Relief Commission, presenting the eight ideas,
complete with estimates of reliability, cost, and construction time for each
option. “All our studies of centuries-long flood records in Europe show that
the maximum flood in 1,000 or 2,000 years is likely to be not much more than 20
or 25 percent greater than the maximum flood of a century or two,” he explains.
“And a flood of 40 percent greater appears beyond all possibility. Thus, I recommend
that we build the flood control works large enough to control runoff 40 percent
greater than that of March 1913.”
He turns and gazes at his audience. “Had
this system of earthen dams and dry detention basins been in place before
March, the excess runoff would have been distributed over more than two weeks rather than all descending on
Dayton in four days!” he exclaims.
“This is awfully ambitious,” one commission
member ventures doubtfully. “How long will it take to build?”
Morgan is ready with his astonishing
calculations. “To protect the entire Miami Valley with dry detention basins
would take only half the construction time and less money than to protect
Dayton alone by local works!” he declares. “Of course, it will take some time
for the legal proceedings to obtain the lands needed. But once legal matters
are settled, I have no doubt we can build all five earthen dams in just two or
three years!”
Morgan has just mapped out the single
largest-scale engineering project ever yet undertaken in the United States. As
such, it blazed trail both legislatively and technically.
The Dayton Citizens’ Relief
Commission approved his final plan in February 1914. As the proposed system of
detention basins would involve land in nine counties, Morgan drafted a
flood-control bill for the Ohio state legislature. The bill’s final version,
quickly passed and signed into law by Governor James M. Cox, was named the Ohio
Conservancy Act, introducing the word “conservancy” into American English. The Miami
Conservancy District was established in June 1915. 
One of the brand new District’s
first acts was to hire Morgan Engineering Company to turn its engineering plans
into reality, with Morgan himself as chief engineer. In 1918 (after delays in
part due to World War I), the Miami Conservancy District sold two issues of
30-year bonds totaling $34 million—then the largest special-assessment bond
issue for flood control in U.S. history—and began moving earth. 
The five earthen dams were mammoth.
They ranged from 65 to 110 feet high; their crests ranged from 1,200 to 6,400
feet long; their bases were all hundreds of feet thick. Their squat, triangular
cross sections were far more massive than traditional dams to, in Morgan’s own
words, “relieve the public mind of any apprehension as to their possible
failure.” Indeed, Morgan compared the intention of their architecture to that
of the Pharaoh “who built his pyramids on so broad a base that no matter what
mistakes of judgment might be made, or how faulty the work might be done in the
building, they would yet stand through the thousands of years.”
Construction lasted five years and
was completed without fanfare in 1923. Morgan’s analogy of the project to
Pharaoh’s pyramids was apt. The Great Pyramid of Cheops stands 40 stories tall
and has a volume of 3.5 million cubic yards—but the men building the Miami
Conservation District dams rearranged a volume of earth almost equal to five Great Pyramids
In 1922, Engineering Record awarded the Miami Conservancy District’s flood
protection system its distinguished Project of the Year Award, placing it in
the company of such other international engineering design feats as the
Brooklyn Bridge (1883) and the Eiffel Tower (1889), as well as the later Golden
Gate Bridge (1937), the Gateway Arch (1965), and the Channel Tunnel (1994). And
in 1972, the five earthen dams were designated a National Historic Civil Engineering
Landmark.
Most importantly, since their
completion, the five dams have held back floodwaters more than 1,500 times.
Even in 1937 and 1982 (when rainfall and flood stages over the Midwest
approached the magnitude of 1913 and inundated surrounding communities), and in
1959 (year of highest watershed runoff in the Miami Valley since 1913), the
areas protected by the Miami Conservancy District dams—including downtown
Dayton—never flooded.
Happy 90th birthday, Morgan’s
Pyramids!
©2013
Trudy E. Bell. For permission to reprint or use, contact Trudy E. Bell at t.e.bell@ieee.org
Next
time: 1913–2013 Centennial Events Updated
CAPTIONS
(for all but first photograph)
Morgan’s
five earthen dams (green) are placed at strategic locations where the valleys
for each of five rivers are narrowest. Blue indicates the areas that become
inundated when the dams are holding back floodwaters. Red shows levees and
other local flood protection works downriver. The entire project involves land
in nine counties. The little inset map of Ohio shows the scale of the Miami
watershed. [Credit: Miami Conservancy District]
Five
photographs document the construction of Taylorsville Dam across the Miami
River between July 1920 and its completion in March 1922. An idea of its size
is given by the tiny human figures. (Specific engineering details shown in each
image are described in Chapter 6 of The
Great Dayton Flood of 1913 by Trudy E. Bell.) [Credit for all five images:
Miami Conservancy District]
The Miami
Conservancy District also built local flood protection works near and in urban
areas, which consist of earthen levees (far right), solid concrete revetments
(large slabs in the center), and flexible revetments (small blocks closest to
the river). [Credit: Miami Conservancy District]
Englewood
Dam, the largest of Morgan’s Pyramids, is 6,400 feet long
and is topped by U.S. Route 40. It crosses the Stillwater River, which in this
photograph flows from left to right. The dry detention basin at left has now
filled with trees, and serves as a recreation area in non-flood times.
Photograph was taken around its 70th anniversary in 1993. [Credit: Miami
Conservancy District]
Selected references
History of
the Miami Conservancy District and its engineering feats is detailed in three
main works: C. A. Bock, History of the
Miami Flood Control Project (State of Ohio: The Miami Conservancy District,
Dayton, Ohio, 1918); Arthur E. Morgan, The
Miami Conservancy District (New York: McGraw-Hill Book Co., Inc., 1951);
and Carl M. Becker and Patrick B. Nolan, Keeping
the Promise: A Pictorial History of the Miami Conservancy District (Landfall Press, Dayton, Ohio,
1988)
For
statistics on the dams, see Ivan E. Houk, Rainfall
and Runoff in the Miami
Valley
For the
centennial of the 1913 flood, the Miami Conservancy District
has launched a website http://www.1913flood.com
listing commemorative events being planned around the Miami Valley. It is also
producing a centennial book A Flood of
Memories
.
Much of this
installment was based on Trudy E. Bell, "Taking Engineering byStorm," The Bent, 95 (1): pp.
15-22, Winter 2004, which also details many of the project’s technical and managerial engineering
firsts.
All of Chapter Six “Resolve”—featuring 39 photographs—is devoted to
Morgan and the
construction of the Miami Conservancy District dry dams for flood control in
Trudy E. Bell, The Great Dayton Flood of
1913 (Arcadia Publishing, 2008), a picture book of nearly 200 images of the
flood in Dayton, rescue efforts, recovery, and. (Author’s shameless marketing
plug: Copies are available directly from me for the cover price of $21.99 plus
shipping, complete with inscription of your choice; for details, e-mail me at t.e.bell@ieee.org )
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