Just to demonstrate how close the sea is to the lower end of the site (some of which has already been lost to coastal erosion) here we have Keith (who in the real world visits schools and performs as a professional re-enactor) and Chloe excavating in what is currently the earliest Iron Age part of the site. They are getting lots of juicy material from midden deposits, and now have found a wall down there.
This part of the site is now below the water table, but the tide does not quite get to it (only to within about 2 m) but they are on a spring line so have to bail-out the small sump every 40 minutes, so that they can continue working.
We have not yet got to the base of the site down there, which we know lies at least a meter below the current beach ... a clear indication of sea-level rise should you need one.
Follow the story on the Swandro Dig Diary; and on Twitter @SwandroOrkney and @WessexArch.