Chicago Yacht Club

To shield their shores from waves that can cause flooding and erosion, cities throughout the Great Lakes region have replaced natural nearshore habitats with sea walls, breakwaters, and other "hard" structures. This sea wall helps protect nearby recreational and economic centers like Grant Park and Michigan Avenue against everything from changing water levels to heavy summer storms to the natural ebb and flow of Lake Michigan.

Hard shorelines have their own problems, though. Sea walls change the natural movement of water and sand. They can't absorb wave energy. Instead, they push it back towards the lake, creating harsh waves that crash against land beyond the protection of the sea wall and rapidly erode that shoreline. Sand also builds up against artificial structures, choking off habitats there while starving beaches down shore. This is exactly what is happening along Chicago's North Shore. Sea walls and other artificial structures built near the northernmost suburbs have deprived other southern beaches and nearshore habitats of sand and sped up erosion. The man-made structures lining Illinois' shore may shield some land from flooding and erosion, but the shoreline as a whole is actually experiencing more of both as a result.