Riprap to resist wave and ice loads acting on the upstream slope of an embankment dam

Abstract

In areas with cold climate formation of ice cover on a reservoir exerts loads on the upstream slope of an embankment dam which can cause degradation and erosion damages. Riprap is generally provided on the upstream slope of embankment dams to counteract both ice and wave action. The sizing of the riprap to resist wave action is well established with simple empirical formulas. First the wave height is estimated, usually through simple wave prediction formulas. Subsequently, wave height is inserted into empirical rock sizing formulas for determining the riprap stone size required to resist the wave action. Some dam design guidelines assume that riprap designed to resist the wave actions is also capable of resisting the ice action, while others, such as the Norwegian guidelines, consider ice action through a requirement on the minimum weight of individual riprap stones. The available riprap design measures for resisting wave and ice will be investigated. Furthermore, the conditions where the design against ice loading may be governing will be discussed.