Evaluation of the Use of a Bedleveler to Improve Navigability of Atchafalaya River Bar Channel Fluid Mud

Between routine navigation dredging operations, the Atchafalaya River Bar Channel (ABC) traps fluid mud, which begins to consolidate. The consolidated mud can begin to block the passage of vessels using the Port of Morgan City, LA. If the mud densities and yield stresses could be kept sufficiently low so that vessels could safely navigate through it, the length of time between navigation dredging could potentially be increased. To demonstrate the feasibility of dragging a large object through the mud to condition the sediments, a bedleveler was constructed and suspended below a barge at depths that penetrated the interface between the water and the fluid mud in the channel (i.e., the lutocline). The barge was towed along the ABC parallel to its axis, thereby dragging the bed leveler through the fluid mud on the channel bottom. It was found that dragging the bedleveler along the channel seemed to have no effect, or an extremely limited effect, over a short duration on the densities. It cannot be ruled out that the bedleveler operations had an effect on yield stresses, but the measured decreases were so inconsistent that naturally occurring changes or other factors had a larger effect.