Final answer:
Coastal floodplains are characterized by their flatness and susceptibility to flooding, protection from direct wave impact due to coastline orientation, and significant deposits of sediments during lowstands.
Step-by-step explanation:
Coastal floodplains are flat expanses of land adjacent to a coast, which are subject to flooding from the sea. These areas, sometimes known as coastal plains, have several essential features that are shaped by both geomorphic and climatic processes.
Protection from Waves
One important feature is the protection provided by specific coastlines. Some coastal floodplains experience minimal wave impact due to their orientation or a lack of exposure to long stretches of open water, reducing the frequency and severity of flooding events from storm surges and high waves.
Sediment Deposits During Lowstands
Another significant aspect of coastal floodplains is the presence of sediment deposits, particularly during periods known as lowstands, when relative sea level is low. During these times, the continental shelf and carbonate platforms are exposed and extensive deltas can form at the margin. This leads to large amounts of sediment being transported into deep marine basins, contributing to the floodplain's geological development.
Coastal floodplains serve not only as significant ecological habitats but are also vital for nearby human settlements, providing areas for agriculture, settlement, and nutrient-rich soils.