A stable beachy coastline is in dynamic equilibrium. Erosion is the result of more sediment being washed away from the system than is deposited. The root cause

A stable beachy coastline is in dynamic equilibrium. Erosion is the result of more sediment being washed away from the system than is deposited. The root cause of the disturbance in the system is probably some damn in a river which is mentioned in the article. A local measure that reduces wave energy creates a sediment trap, reducing or reversing local erosion.. However some where downstream from this site there is now less sediment coming in than is going out. So there it is going to erode now. These type of measures usually end up pushing the problem downstream (a coastal system has a dominant sediment transport flow direction). Actual solutions must look at an entire coastal system and usually involve continuous dredging, damn removal or lots of breakwaters, walls etc. This is all well known amd cam be modeled to a pretty good accuracy with software. However time amd time again a town solves their problem by pushing the erosion to their neighbours .