History of Protecting Embankment Dams with Concrete Block Systems

Using articulated concrete blocks as an embankment dam overlay can provide economical erosion protection, according to recent research.

By Paul E. Clopper

Dam owners are frequently confronted with the costly and difficult task of retrofitting existing embankment dams and associated outlet works to accommodate current estimates of the probable maximum flood (PMF). Searching for a cost-effective retrofit, engineers have recently considered placing a protective overlay on the embankments and allowing limited overtopping. This armoring of the embankment protects against damaging and potentially catastrophic erosion caused by steep-slope, high-velocity flow. Embankment armoring is an alternative to the more costly and time-consuming methods of enlarging flood control spillways, raising embankments, or extending outlet control structures.

Structural (reinforced) concrete and, more recently, roller-compacted concrete traditionally have been used for embankment armoring to achieve the desired level of performance and stability.  However, articulated concrete block revetments (a series of individual blocks placed together to form an overlay) now offer another viable armoring option.  An articulated concrete block revetment may be the method that can achieve the desired level of stability for the least cost.  Advantages of the method are its low cost compared to conventional protection techniques and its applicability to a wide range of hydraulic conditions.

Hydro Review / April 1991