Beach Morphology and Types
Mean High and Low tides
Subtidal Zone
Intertidal Zone
Supratidal Zone
Nearshore Environment: Low tide out across the surf zone and includes sand bars (depends on wave energy, availability of sediment-often a combination of sand bars and troughs)
Characterized by sand ridges/shore parallel bars. Range from 30-50 m offshore.
Ridge and Runnel Feature- sand bar type feature built by the movement of sand landward by waves. Ridge migrates onto beach and is reworked into the sand
Foreshore Environment: Includes SWASH zone. Also called the forebeach or beach facechanges with wave energy. Intertidal part of the beach up to the landward slope change.
Slope changes with wave energy. Pebbly beaches have very little energy on the wave return and so move sediment landward.
Backshore Environment: Extends from the change in slope of the bermcrest to the next feature
(dunes, cliffs, seawall)
Wind transport is common creating small ripples.
Often horizontal or landward dipping
Storms can cause a great deal of erosion here stable
Storm ridges are possible-coarse material washed up onto the backshore and relatively
Beach Types:
Continuum of types from DISSIPATIVE (shallow slope with deposition) to
REFLECTIVE (steep slope with erosion-no wave energy loss)