June 7, 1939
The Marked Tree Lock and Siphons began operation. The siphons are used to control water flow on the St. Francis River. They were built in response to the Flood of 1927, which broke levees and flooded much of the town of Marked Tree (Poinsett County). They are of historical significance because they were important elements of the St. Francis River Basin Flood Control Project and the U.S. Corps of Engineers’ flood control plan for the Mississippi River Valley. According to the Corps of Engineers, they are unique in architectural achievement. The lock was completed in 1926. It is about nine miles away from Marked Tree, on an abandoned artificial channel of the St. Francis River.