Sunday, January 27, 2013

Morgan's Pyramids

Arthur E. Morgan’s fundamental solution to save Dayton was monumental—but elegantly simple.

             “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

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 (State of Ohio, The Miami Conservancy District, Technical Reports, Part VIII, Dayton, Ohio, 1921). p. 215. For the failure quote, see Morgan, p. 248. For the pyramids quote, see Becker and Nolan, pp 137-38.
For the centennial of the 1913 flood, the Miami Conservancy District has launched a website 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 )


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