Sandbags at the Royal Victoria Pavilion

Any of you got any idea what they are collecting the sand for? Click on the picture to enlarge. Perhaps they are expecting an exceptionally high tide or perhaps preparing sandbags for war defences. As you don’t often see photographs of this sort of thing I would imagine that it relates to some fairly important event. Tea at 2d less than 1p per cup suggests the early 1900s and they do all look very happy with their lot in life so if they are working for the council that also suggests quite a long time ago