Coastline Change App: Historical Data Fact Sheet
Shorelines constantly migrate as waves, tides, sea-level changes, and sand supply reshape beaches and barrier islands. By measuring shoreline movement over time, scientists gain insight into coastal processes and evaluate how beaches and barrier islands evolve.
Subject Tags
- Coastal
- Climate resilience
Summary
Shorelines are the intersection of land and sea and move constantly over sandy coastal environments such as beaches and barrier islands. Shorelines move (or migrate) in response to oceanographic and geologic processes that operate over a variety of time scales. On one end of the time spectrum, daily waves and the currents resulting from the change in tides move sediment (sand) that can make shorelines move. On the other end of the time spectrum, changes in sea level (rise or fall) and/or to the supply of sand (increases or decreases) influence the direction and rate that shorelines move.
The current state of scientific knowledge does not enable a cause-and-effect analysis of shoreline movement (or migration). In other words, we can measure the rate at which shorelines move, but cannot conclusively explain “why?” they move. Consequently, coastal scientists, land managers and planners use the rates of shoreline movement (in meters or feet per year) as a proxy for (or representation of) the processes that erode, transport and deposit sand and to assess the mobility of beaches and barrier islands. In other words, measurements of the rate and direction of shoreline movement (ie, migration) provide insight into the mobility of beaches and barrier islands and into the processes that are responsible for causing shorelines to move.
Citation
Island, B. Coastline Change App: Historical Data Fact Sheet.