Its top surface may slope shoreward. Backbeach Dunes occur when wind off the beach carries sand shoreward. Sea Cliffs that are inactive may lie inboard of the backbeach or dunes. With a change in climate or sea level, parts of the beach may be eroded away and the sea cliff will then become active. C. Energy Sources in the Beach Environment 1.
Surface waves are the primary source of energy in the beach environment.
They typically refract as they enter the Surf Zone and entrain sediment in the breakers as they move shoreward. Longshore currents and rip currents are formed as a consequence of the onshore wave activity. Tides also influence the position of the Surf-Berm beach zones creating a broader zone in which waves are active along the beach margin. Changes in tides cause alternating intervals of deposition and erosion on the shore face and variations in the local beach water table. Seasonality of wave energy.