Coastal retreat is the gradual landward movement of the shoreline caused by erosion, storms and rising sea levels. It can also refer to managed retreat—the planned relocation of homes, roads and infrastructure away from vulnerable coastlines instead of repeatedly rebuilding them.
What Is Coastal Retreat?
Coastal retreat is the inland movement of beaches, dunes, cliffs and shorelines over time. As waves,
tides, currents and storms remove sediment, the coastline naturally migrates landward.
Scientists also use the term managed retreat to describe policies that relocate
buildings and infrastructure away from high-risk coastal zones rather than attempting to stop
erosion indefinitely.
Why Coastlines Retreat
- Continuous coastal erosion
- Powerful storm waves
- Storm surge and coastal flooding
- Sea-level rise
- Longshore currents removing sediment
- Barrier island migration
- Cliff collapse and landslides
- Reduced sediment supplied by rivers
- Human development blocking natural shoreline movement
Natural Retreat vs. Managed Retreat
| Type | Description |
|---|---|
| Natural Coastal Retreat | Shorelines gradually migrate inland through erosion and sediment movement. |
| Managed Retreat | Communities intentionally relocate buildings and infrastructure away from high-risk coastlines. |
| Engineered Protection | Seawalls, groynes and beach nourishment attempt to slow erosion but usually cannot stop long-term coastal change. |
Signs That a Coast Is Retreating
- Narrowing beaches
- Loss of coastal dunes
- Frequent cliff collapses
- Roads closer to the shoreline each decade
- Buildings threatened by erosion
- Repeated storm damage
- Saltwater reaching formerly dry land
- Barrier islands migrating inland
How Communities Adapt
Coastal communities use different strategies depending on local geology, economics and risk.
Some build seawalls and revetments. Others restore dunes and wetlands. Increasingly, governments
are considering managed retreat where long-term protection becomes impractical or prohibitively expensive.
- Beach nourishment
- Dune restoration
- Wetland conservation
- Living shorelines
- Flood-resistant construction
- Building setbacks
- Managed retreat programs
Is Coastal Retreat Always Bad?
No. Coastal retreat is a natural process that has shaped shorelines for thousands of years.
Problems arise when permanent infrastructure is built where the coastline naturally wants to move.
In many places, allowing dunes, wetlands and barrier islands to migrate naturally can provide
better long-term protection than attempting to freeze the coastline in place.
Coastal Retreat and Climate Change
Rising sea levels increase the frequency of coastal flooding and allow waves to reach farther inland.
Although local geology and storms remain the dominant drivers of erosion in many locations,
sea-level rise increases the long-term rate of shoreline retreat on many coasts worldwide.
Related Coastal Topics
Frequently Asked Questions
What is coastal retreat?
Coastal retreat is the gradual inland movement of the shoreline caused by erosion, storms, waves,
sea-level rise and natural sediment transport.
What is managed retreat?
Managed retreat is the planned relocation of buildings, roads and infrastructure away from
vulnerable coastal areas instead of continually rebuilding them.
Does sea-level rise cause coastal retreat?
Sea-level rise increases long-term shoreline retreat by allowing waves and storm surge to reach
farther inland more frequently.
Can coastal retreat be stopped?
Coastal retreat can often be slowed locally through engineering, but most coastlines continue to
evolve naturally over time.
Why are barrier islands retreating?
Barrier islands migrate because storms, waves, tides and sea-level rise constantly redistribute
sand across the island system.
