The Coastal Lines of Defense concept, developed by Dr. John Lopez of the Lake Pontchartrain Basin Foundation, is a way of explaining how the protection of the ecology and communities of coastal Louisiana depends on a combination of manmade and natural structures to insulate them from the sea. A surprising number of different elements come into play and no one element will necessarily be dependable unless working in concert with the others. The Friends of the Manchac Greenway on the Isthmus of Manchac recognizes and advocates for the sustainability of our “land bridge” as a critical barrier protecting not only a vital national transportation corridor but also the very existence of Lake Maurepas, it’s fresh water ecology and the wetlands beyond that protect the communities of the western Upper Pontchartrain Basin.