Protection Against Scour at SAF Stilling Basins

Abstract

Severe scour may occur downstream of SAF stilling basins and some type of protection may be required to ensure the integrity of the structure. Tests were conductred using physical models to determine the minimum size and length of riprap required for stability when the riprap was placed at the elevation of the end sill and the elevation of the basin floor. For both placements, the size of riprap required for stability increases exponentially with the Froude number. Larger riprap is required for stability when the riprap is placed at the end sill elevation compared to when it is placed at the basin floor elevation. Relationships are presented to determine the size and length of riprap required to ensure basin integrity.