ridge and runnel A series of asymmetrical ridges running parallel to the coast and separated by shallow troughs (runnels) 100–200 m wide. This topography is developed on the foreshore of mesotidal or macrotidal beaches. The development of these forms is favoured by moderate wave-energy conditions acting on a flat beach with an abundant sediment supply.

ridge and runnel A series of asymmetrical ridges that run parallel to the coast and are separated by shallow troughs (runnels) 100–200 m wide. This topography is developed on the foreshore of mesotidal or macrotidal beaches and is favoured by moderate wave-energy conditions acting on a flat beach with an abundant supply of sediment.