Margaret River Mouth Beach (WA 660) lies across the mouth of the usually blocked river.
The beach faces southwest and curves for 500 m between boundary calcarenite bluffs of the old valley side to the south and a low reef to the north, where it forms a sandy foreland. It is backed by the dammed river which can break out and either end of
the beach, resulting in a flat overwashed area behind the steep beach. [src
http://beachsafe.org.au/beach/wa0660]