Stone Gabions are useful to control erosion around bridge and culvert structures or other locations subject to scouring at the base of the embankment or drainage channel. Gabions and mattresses consist of rectangular units, fabricated from welded wire fabric or twisted hexagonal mesh zinc or PVC (polyvinyl chloride) coated wire. Filled with stone, gabions become large, flexible and permeable elements from which a broad range of structures can be built (retaining walls, river bank protection, weirs, etc.).