Wind impacts drowned valley coasts by driving waves
, which carry sediment to the estuary mouth. If wave energy is higher than tidal energy, it can create a wave-dominated estuary
. Waves move sediment alongshore and onshore into the mouth of the estuary, forming sandbars or subaerial barriers and spits. These barriers prevent much of the wave energy from entering the central basin, which allows fine sediments to accumulate and encourages marshes to form.