Soil and Water Conservation Works - Afforestation, Reforestation and Forest Restoration in Arid and Semi-arid Tropics - page 103

After completion of the embankment the upstream slope is pitched with large
sized stones—usually not less than 20 cm in thickness—underlain by a 10 cm thick
layer of mines waste or stony soil. If a spillway has been provided, the pitching
must start where the wingwalls joint with the embankment. The downstream of the
spillway must be pitched and guide walls of suitable height—usually 0.5-1 m—are
constructed on both the sides of this pitching.