It had an open coastal barrier to marine water but also had extensive inflow of freshwater from melting glaciers.
The coastal barriers north and south of the entry to the Kaipara Harbour, are essentially consolidated sand dunes, built up over the last few million years.
This removed the coastal barrier that had protected the beach which was undermined and washed away.
Development can render coastal barriers more vulnerable to destruction and is itself vulnerable to damage from changing water levels and shifting sand.
"If we could go back a hundred years and recommend no building on the coastal barriers, we would do so," said Mr. Smith.
"But excluding coastal barriers along the West Coast and the Great Lakes from similar protection is short-sighted and unfair."
Dr. Moore is using data on past barrier island migration to predict how coastal barriers will fare as the sea level rise accelerates.
This was shown studying the coastal barriers on the Atlantic coast of Nova Scotia.
In no way does the Act regulate how individuals develop their land on and around areas of coastal barrier.
Instead, it directs that Federal dollars not be spent for development purposes on designated coastal barriers.