Tuesday, January 11, 2011

Testing the sand drift

On the summer by the sea walk we tried a simple experiment. By quickly digging a trench in front of a wave, then we watched carefully as the backwash from the wave refilled the trench.

Thanks to steve for the video
image If you watch, you will see the first and main backwash is from the top right (south eastern side), but then material also washes in from the top left (north western side). So the waves are not washing back down the beach in a uniform direction and maybe even our trench is influencing the backwash a little. Still we repeated the test three times with much the same result. So we must assume an inconclusive result that the sand is mostly washing to the north west (ie coming from the south east) which is consistent with the form of the sand bars, which joins to the beach at the southern end in this location.

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