Take a look at his beach diagram of beaches typically found together with sand dunes just like on our Ogunquit Beach. Not all beaches are like this, of course, look at York Beach or Wells Beach. You can see from the diagram, the levels of high and low tide and the wet beach is the area between them. Of course the beach changes as the seasons change – anyone who walks our beach is familiar with these changes.
As you can see, the near shore zone extends to a depth of about 5m. A lot of sand is moved around in this zone because it is stirred easily by most waves.
But the shore extends further down, to depths of 20m or more. At some time during a year or decade, the sand here is stirred by large storms and moved towards the beach.
Going from the wet beach inland, one encounters the dry beach, outside reach of the waves, but high waves during spring tide may deposit sand here. This part of the beach is partly formed by wave overwash and by the wind heaping the sand up. It can even be considered a fore-fore dune.
We have tried to protect our dunes, rebuilt as they were in the 70s, since they protect the marsh behind them and since they can also feed the beach in that process of exchanging sand we have witnessed.