Answer to Question #77682 in Physical geography for Shreya

Question

How does beach recharge affect the beach profile? do it make the beach flatter or steeper and why?

Answer 1

Coarse beaches are steeper because the large pores between coarse clasts provoke greater percolation plus less backwash; and, the coarse material has a higher angle of repose. Backwash volume is greater along less permeable fine grain beaches resulting in flatter profiles. Saturation reduces permeability and increases backwash and porewater pressure promoting a flatter beach. Groundwater discharge and large short period waves boost saturation and decline percolation. Changes in permeability are related to wave steepness. As wave steepness increases beaches become flatter. Wave period, height, and length determine the volume of water reaching the beach at any one time. When wave heights increase, as during a storm the beach face becomes saturated reducing the infiltration capacity of sediment. As a result, backwash increases and more sediment is carried seaward; and, the beach becomes flatter. 

References
Factors Shaping the Beach. (n.d.). Retrieved June 1, 2018, from https://w3.salemstate.edu/~lhanson/gls210/GLS210_coasts/beach.htm