Riprap is loose, angular stone that interlocks well to act as ‘armour’ for erosion control. Typically made of our hard granite or limestone, but can also be made from a number of other rock types. Riprap is placed along graded ditch, channel, and shoreline banks over geotextile, which prevents erosional undercutting in areas of concentrated flow or wave energy. It can also be used to construct retention berms for sediment traps and dams protecting high velocity culvert inlets.

Riprap is also used to stabilize areas on a construction site with high erosive power by increasing surface roughness and slowing the runoff. Applicable areas on a site may include inlets and outlets of storm pipes and culverts, bridges, drains and storm drains. Riprap is also effective for protecting and stabilizing slopes, channels, streambanks, and shorelines.