The sea wall from that image seems to be relatively thick, though the shadow is making it a bit weird. Not sure if anyone is familiar with cruise ship pools though they usually a wide shallow shelf to make it appear bigger than it actually is. if you compare that image with the flooded image it makes it appear the seawall is only as wide as the roads, were we do have an extra thickness there.
I'll illustrate
these 2 pictures show that it is quite shallow from the road to where the drop off must be, the 2nd image is on an angle and without knowing how much the picture is at an angle and the angle of the shelf we can't determine the length before the drop off.
This would be my guess using sophisticated modelling software (MS Paint)
(20min delay)