This is the second installment of Col. Zachary Miller’s recent road trip around the district. At this stop he had opportunity to see and learn about Eastern Arkansas’ Marked Tree Siphons (or syphons) – a flood control facility the Memphis District built 80 years ago that is still in operation today!
The Siphons are a unique application of an engineering structure of their type, designed to lift the flow of the St. Francis River over an earthen levee and deposit it in the river channel on the other side of the levee.
Drainage District 7 of Poinsett County, Ark., operates the Siphons during high water conditions. DD 7 Director of Operations Doyle Hillis met Col. Miller at the facility, explained its history and purpose, and demonstrated operation of the controls.
Memphis District engineers designed and installed the Marked Tree Siphons from December 1938 to June 1939. Constructed in the district shops at a cost of $215,000, the three nine-foot-diameter, 228-foot-long, electronically welded steel tubes were among the largest in the world. Their operation is deceptively simple. First, a vacuum pump primes each syphon. Once the syphon is primed, the vacuum pump is turned off, and the flow is self-sustaining. An air valve regulates the rate of flow.
On June 7, 1939, hundreds of spectators attended the dedication of the Siphons. A correspondent for the Marked Tree Tribune incredulously reported: “A whole river was lifted 30 feet across a dam and deposited on the other side.” In his address, Memphis District Engineer Maj. Daniel Noce described the siphons as the only ones of their type in the world and as “unique in the annals of engineering.”
The Marked Tree Siphons are on the National Register of Historic Places.