Wednesday, 6 February 2013

Sand Dune formation in action

The view of our dunes from the estuary

Every time we step out onto the beach we are never quite sure how the frontal dunes are going to look.  Our dunes are constantly changing as they are susceptible to the wind and the waves.  A wind as low as 5 meters per second can lift a grain of sand and move it along the beach.  Marine debris, litter or vegetation can intercept these grains trapping them, forming little hummocks of sand, these are called embryo dunes. 
Embryo dunes forming near our car park
The main dune system at Sandscale consists of three dune ridges separated by areas at ground water level, these are called dune slacks. The fore dunes (yellow dunes or white dunes) rise to about 10m along the northern edge of the dune system and about 15-20m on the more exposed westerly point.
Two of our dune ridges
The steepening of the beach at the northern edge, the high tides, heavy winds and human pressure are all leading to increased erosion at the northern end of the site.  With the changes in the Duddon river channel sculpting the frontal ridges into shallow bays and points
Heavy erosion near our blow out
Storm waves are destructive in nature as they break steeply with a powerful backwash however they also provide accumulation of larger stones and shingle up the beach. Much of this material, and the rocks which compose the shingle, originates from the western and central fells of the Lake District and further north from western Scotland

Erosion from the waves in progress


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