lagoondeltas

Lagoondeltas are a specific type of delta formation found where rivers carrying sediment meet a lagoon. Unlike marine deltas that discharge directly into the open ocean, lagoondeltas deposit their load into a sheltered body of water. This lagoon acts as a barrier, often reducing wave energy and allowing for finer sediment deposition than might occur in a more exposed environment.

The process begins as a river, laden with silt, sand, and clay eroded from its watershed, flows towards the coast. Upon reaching the lagoon, the river's velocity decreases dramatically. This reduction in speed causes the suspended sediment to settle out of the water column. Over time, this accumulated sediment builds up, forming a deltaic landform that gradually progrades into the lagoon.

Lagoondeltas are characterized by their intricate network of distributary channels, similar to other delta types. However, the morphology and sediment distribution can be influenced by the lagoon's size, depth, and connection to the sea. If the lagoon is shallow and has limited exchange with the ocean, the delta may become more terrestrial in character as it fills. Conversely, a deeper lagoon with significant tidal influence might exhibit more complex sedimentary structures. These environments are often rich in biodiversity, supporting unique ecosystems adapted to the brackish or freshwater conditions and the muddy substrates.