Waves, tides, currents, storm surge, sea level rise, shoreline retreat, cliffs, beaches, dunes, wetlands, sediment supply, armoring, living shorelines, nourishment, infrastructure, flood risk, and coastal resilience
Coastal erosion
Coastal erosion is the wearing away and movement of shoreline land by waves, currents, storms, sea level rise, and changes in sediment supply.
What coastal erosion is
Coastal erosion is the loss or displacement of land along a shore. It happens when waves, currents, tides, storms, wind-driven water, or sea level rise remove sediment or rock faster than it is replaced.
How waves reshape shores
Waves attack beaches, dunes, bluffs, cliffs, marsh edges, and built shorelines. During storms, higher water levels allow waves to reach farther inland, undercut slopes, move sand offshore, and damage protective landforms.
Sediment supply
Shorelines need sediment to maintain beaches, bars, dunes, wetlands, and deltas. Dams, levees, dredging, shoreline structures, river changes, and development can reduce or redirect the sediment that would otherwise rebuild coasts.
Sea level rise
Rising relative sea level can make erosion worse by letting waves and tides act higher on the shore more often. Local risk also depends on land subsidence, storms, geology, coastal shape, and human modifications.
Cliffs, beaches, and wetlands
Different coasts erode in different ways. Cliffs may fail suddenly after undercutting or heavy rain, beaches may narrow or migrate, and wetlands may drown or fragment if they cannot gain elevation or move inland.
Shoreline armoring
Seawalls, revetments, bulkheads, and other hard structures can protect specific assets, but they may reflect wave energy, narrow beaches, block habitat migration, or move erosion problems to nearby areas.
Nature-based responses
Living shorelines, dune restoration, marsh protection, oyster reefs, beach nourishment, setback zones, and sediment management can reduce erosion while preserving more coastal function. They work best when matched to local wave energy and site conditions.
Why it matters
Coastal erosion affects homes, roads, ports, wetlands, beaches, cultural sites, fisheries, tourism, and public safety. Understanding it helps communities decide where to defend, restore, elevate, relocate, or leave space for the coast to move.