We salvage materials from the surrounding land and river bed: river rock to form gabion cages, floors and walls, and reed to cover doors and ceilings. (treehugger.com)
Compact underwater gabions also dot the surrounding reefs to absorb the energy of waves, while tree planting helps prevent water inundation. (scientificamerican.com)
Other alternatives include gabions, or cages, of net or metal wire that are filled with rocks to fortify shorelines. (scientificamerican.com)