Which zone lies behind dunes and forms where sand is deposited during storm-driven passes, often colonized by grasses?

• A. Dunes
• B. Barrier Flat
• C. Low Salt Marsh
• D. Peat Deposits

Answer: (B)

In coastal barrier islands, the backshore features a flat, sandy area behind the dunes where storm-driven sand is deposited. This zone is called the barrier flat. When storms push sand landward over the foredunes, the newly deposited material settles in this low, flat space. Grasses such as sea oats and beachgrass quickly colonize these sands, and their roots help stabilize the surface while their growth traps even more sediment. Over time, this creates a relatively level, grassy, sand-rich area that sits landward of the dunes.

This zone is distinct from the dunes themselves, which are the raised ridges built by wind on the immediate shore; from a low salt marsh, which is a wetter, tidal environment with waterlogged soils and salt-tolerant plants; and from peat deposits, which form in waterlogged wetlands where plant material accumulates as peat. The barrier flat’s defining features are its location behind the dunes, sandy deposition during storms, and grasses that stabilize the surface.