During the mid-19th century, manmade channel alterations, including the removal of a large log jam and dredging, permanently connected the Atchafalaya River to the Mississippi River. From then until the completion of the Old River Control Structure in 1963, the Mississippi was increasingly diverting flow into the shorter and steeper path of the Atchafalaya channel. By law, a regulated 30 percent of the latitudinal flow water from the Mississippi, Red and Black rivers is diverted into the Atchafalaya at the Old River Control Structure. This flow diverts on average 25 percent of the Mississippi River flow down the Atchafalaya.