Seepage effects in some riprap revetments

Seepage can be an important cause of failure in riprap revetments, especially on streambanks consisting of layered alluvium, and on stage-controlled rivers. Revetments can be protected against seepage by filters designed according to widely accepted principles. Nevertheless, numerous widespread failures caused by emergent seepage have been observed in riprap revetments. The factors that most significantly affected the apparent severity and extent of seepage effects on revetments were alluvial layers of protected soil in which gradations varied from layer to layer and the persistence of a source of seepage water. Design and construction of these failed revetments did not prevent or accommodate the effects of seepage through the multilayered soils behind the revetments.