Waves attacking a salt marsh boundary

Curator's comment:

This is a wonderful example of how the fine details of how a process works can be very important! These small waves have very little energy to erode the salt marsh. But over time, the waves also have the effect of cutting gullies into the salt marsh. The gullies focus the energy of the waves, resulting in a higher rate of erosion.

Description

The lateral erosion of salt marshes is dominated by wave action and the erosion rate is often shown to be a linear function of wave power. Marsh shoreline retreat can be locally accelerated through manifestation of wave-cut gullies; their convergent geometry concentrates incoming wave energy. Here, moderate wind events produce relatively small waves (~30 cm) yet marsh erosion rates within the lagoon are on the order of 1-2 m/yr.

Shared by: Anthony M. Priestas

Location: Hog Island Bay, Virginia, USA