Assessment Of Mississippi River Revetments Using The Self-Potential Method

Abstract

Two of the U.S. Army Corps of Engineers (USACE) primary mission areas are the maintenance of the nation's navigable waterways and development of flood control measures. These tasks are most evident along the Mississippi River where revetments are used to maintain the river channel and prevent riverbank failure. Revetments are structures placed parallel to the river current for the purpose of stabilizing the concave banks in river bends and to form a smooth bank line. Along the lower Mississippi River, articulated concrete mattresses (ACM's) are used exclusively for river bank protection (see Figure 1). An ACM consists of an assemblage of concrete blocks reinforced and held together by a metal fabric to form a flexible, protective blanket over the river bottom (Petersen, 1986). A section of ACM is typically 150 ft wide and extends from the river bank to the center of the navigable channel. Adjacent ACM sections are installed by overlapping the downstream mattress by five feet. The ACM are secured to the river bank with launching cables anchored into the bank material. Over time, ACM's are subjected to numerous cycles of high and low water levels, changing river velocities and currents, and structural fatigue. These factors may cause the ACM to become damaged, displaced by the undermining of streambed material, or buried by sediment. The condition of ACM's must be routinely monitored to determine whether or not remedial or replacement measures need to be undertaken.