Tidal inlet
A tidal inlet is a coastal formation in which the tide transports sea water through the coastline. This can be into a marsh behind the dunes (see Fig. 20), or through a string of barrier islands into a lagoon (for example the Venice lagoon in Italy). In contrast to an estuary, no discharge of river water is present. During flood, a landward transport of sea water takes place which is reversed during the ebb.
Tidal inlets exist on completely different scales. This is illustrated at the Wadden Sea. The tidal inlets between the barrier islands are enormous, while the tidal inlet "The Slufter" at Texel is very small (see Fig. 20). Here the water flows into the area between the two dune rows when the tide is high.

Delta
Deltas are coastal formations built into the sea by rivers which discharge water and sediment. If the sediment discharge of the river is relatively large compared to the capacity of the sea, deltas can be formed (see Fig. 21).

Barrier island
Barrier islands can be formed in coastal areas with a wide shallow foreshore. The barrier is formed at the edge of this foreshore where the waves break. An example is the string of barrier islands along the northern Dutch coast (see Fig. 22).