Sorry I was unclear. By erosion I meant beach erosion. I do agree that armoring can help preserve a structure like a dyke. The issue is the sand as you mention

Sorry I was unclear. By erosion I meant beach erosion. I do agree that armoring can help preserve a structure like a dyke. The issue is the sand as you mention with the sand engine. In my neck of the woods armoring is falling out of favor as sand replenishment takes over as the primary strategy.