Arkansas’ engineering
The year was 1939, and the devastating floods of 1927 and 1937 were still on the minds of northeast Arkansas residents. The U.S. Army Corps of Engineers performed one of its greatest engineering feats that year to solve a problem.
“The St. Francis River meandered from north to south,” Steven Mitchell wrote for the Central Arkansas Library System’s Encyclopedia of Arkansas. “It carried a considerable traffic of lumber, log rafts and boats. To regulate flooding, a floodway was designed to divert overflow. Where the floodway levee crossed the river north of Marked Tree, a sluiceway was needed to maintain the channel, while a lock would allow river traffic to continue.
“Because the St. Francis was designated navigable to Wappapello, Mo., the U.S. Department of War had to approve changes likely to affect travel or movement of commerce on the river. On Jan. 4, 1924, the department issued a permit for construction of the sluiceway, lock and a floodway sill on the condition that the river channel was maintained. The Steep Gut Floodway, lock and sluiceway were completed in 1926.
“In 1933, 40 feet of the sluiceway broke and dropped to a 30-degree angle, and part of the levee collapsed. Temporary repairs permitted continued operation of the damaged sluiceway. In 1936, the
St. Francis was included in revisions to the Flood Control Act. An inspection by the Corps in October
1936 revealed the levee had seriously eroded. Flow was stopped, and navigation of 64 miles from Marked
Tree to Wittsburg in Cross County was halted.”
Repairs began in December 1937. The following May, floodwaters created a 90-foot levee gap. The sluiceway was damaged beyond repair and eventually was removed.
“The sluiceway and levee failed because they were constructed on a stratum of fine sands that tended to become ‘quick’ when saturated,” Mitchell wrote. “Repair or replacement was deemed too costly, so the Memphis District of the Corps announced it would permanently dam the levee gap with the plan that ‘instead of passing water under or through the dam, water will be siphoned over it.’
“From December 1938 until June 1939, Memphis District engineers designed and installed the Marked Tree Siphons. Constructed in district shops at a cost of $215,000, the three 9-foot-diameter, 228-foot-long, electronically welded steel tubes were among the largest in the world. Their operation was deceptively simple. A vacuum pump primed each siphon. Once the siphon was primed, the pump was turned off, and the flow was self-sustaining. An air valve regulated the rate of flow.”
The siphons were considered an engineering marvel. In the cover story of today’s Perspective section, I write about the levee and drainage districts that changed the face of the Arkansas Delta. The massive effort to clear, drain and then protect millions of acres from floods required innovations such as the siphons.
Another marvel is the Memphis District’s W.G. Huxtable Pumping Station near Marianna, which was completed in 1977. It’s one of the biggest stormwater pumping plants in the world.
Floyd Clay wrote in the 1986 book “A Century on the Mississippi, a History of the Memphis District:” “While on an inspection trip in the New Orleans District, Maj. Daniel Noce, the Memphis District engineer, noticed that the large water mains of New Orleans crossed over levees instead of going under them. From this, he conceived the idea of a siphon over the levee at Marked Tree as a way of eliminating the sluiceway. Upon returning to Memphis, Noce put his engineers to work on the design of such a siphon.
“Engineers from England, France and South America came to observe it in operation. It proved to be almost 100 percent efficient. This at first appears to be impossible, but upon closer inspection the reason can be explained. Once the siphon was primed and water began to flow through its tubes, the velocity of the flow increased from the time it entered the inlet to the time it was exhausted from the outlet. … The overwhelming success of the siphon has attracted worldwide attention as a truly unique feat.”
Hundreds of people turned out for a June 7, 1939, dedication ceremony. The Marked Tree Tribune reported: “A whole river was lifted 30 feet across a dam and deposited on the other side.”
Noce described the siphons as “unique in the annals of engineering.”
“Since 1939, the siphons have maintained the St. Francis River in its channel, as well as protected agricultural resources,” Mitchell wrote. “Tests of the completed siphons revealed an operating efficiency of 97.1 percent, an achievement not thought to have been possible under conditions other than those of laboratory models.”
In May 1988, the siphons were placed on the National Register of Historic Places.
More than three decades after the siphons were installed, the Memphis District began construction of the Huxtable Pumping Station, named after the man who served as chief engineer of the St. Francis Levee District from June 1935 until July 1958. The station prevents Mississippi River backwater from entering the lower St. Francis River basin. This is accomplished by four gravity-flow gates. Meanwhile, 10 enormous pumps remove excess surface water impounded by levees along the Mississippi and St. Francis rivers.
The watershed served by the plant is more than 2,000 square miles, equal in size to the state of Delaware.
“Since the Huxtable plant’s operation was so unique in application of a perimeter cutoff to intercept groundwater, the operation was witnessed and monitored by engineers from all over the world,” Clay wrote.
The first contracts for the $26 million project were awarded in 1971. The plant began operating in January 1977. It can discharge up to 12,000 cubic feet of water per second. After 18 years of service, four of the Fairbanks Morse engines were upgraded in 1995. Upgrades to the remaining six pumps took place the following year. Engines are housed in a reinforced concrete building.
Efforts through the decades to control floods and ensure proper drainage across the Delta changed the face of the St. Francis and tributaries the L’Anguille, Tyronza and Little rivers.
Filled with snags and log rafts, the St. Francis wasn’t navigable in its natural state. W. Bowling Buion surveyed the river in 1836-37 under the auspices of the federal government, but no funds for clearing the river were appropriated by Congress until after the Civil War.
Arkansas writer Cindy Grisham said of the Tyronza River: “It no longer resembles the stream that it was up until the early 20th century as it has been channelized, ditched and had its meander loops cut off. Before the formation of the levee and drainage districts in the late 19th century that rerouted and channelized existing streams, the Tyronza arose out of a body of water called Carson Lke southwest of Osceola.
“From there, it flowed across low, swampy land, a region locals referred to as the ‘scatters of Tyronza’ into Tyronza Lake before narrowing down into the regular path it followed until reaching the St. Francis.
“Tyronza Lake was simply a widening of the river channel, probably as a result of the land falling during a series of earthquakes that occurred along the New Madrid fault line in 1811-12. Carson Lake and Tyronza Lake have since been drained and are used for agricultural land.”
As for the Little River, writer Norman Vickers noted that it’s “not much more than a series of stagnant mud holes due to the channeling and ditching of the Little River Drainage District.”
And as for the L’Anguille, the Encyclopedia of Arkansas said: “Many of the channels feeding into the river have been straightened for agricultural use, which has increased soil erosion. This runoff, combined with the presence of fecal coliform bacteria, resulted in parts of the river being listed by the state as ‘not supporting aquatic life’ in 1998.”