Knowra Tombolo Tombolo A tombolo is a depositional landform of sand or gravel that connects an island to a mainland or another island. It forms where wave action and sediment transport build a narrow ridge across the water.
Wave refraction : The bending of waves as they enter shallow water at different speeds. Waves bend around an island, redirecting energy and sediment toward the sheltered gap behind it.
Coastal geomorphology : The study of landforms and processes along coasts. Tombolos are coastal landforms shaped by interactions among waves, sediment, and shoreline geometry.
Chesil Beach : A shingle barrier beach in Dorset, England, that connects the Isle of Portland to the mainland. It forms the long sediment connection between Portland and mainland Dorset.
Barrier island : A long, narrow island parallel to a mainland coast, separated from it by a lagoon or bay. Unlike a tombolo, a barrier island typically remains separated from the mainland by water.
Longshore drift : The movement of sediment along a coast by waves approaching at an angle. It supplies and redistributes the sediment that can accumulate between an island and shore.
Sediment : Loose particles of mineral, rock, or biological material transported by natural processes. Sand, gravel, and other sediment supply the material from which a tombolo is built.
St Ninian’s Isle : A Shetland island connected to the mainland by a sandy tombolo. Its narrow sandy link is exposed at low tide and submerged at high tide.
Baymouth bar : A sediment ridge that closes or partly closes the mouth of a bay. It spans a bay opening rather than connecting an offshore island to land.
Wave diffraction : The spreading of waves after they pass an obstacle or move through an opening. Wave energy spreads into an island’s lee, where reduced transport can favor sediment deposition.
Wave : A disturbance that transfers energy through water without transporting the water mass as a whole. Waves provide much of the energy that moves sediment around islands and shorelines.
Show all 21