When gabions are used in a water environment, e,g, as channel linings, the water flows through the voids in the gabion rock fill. The backfill to the gabion structure could then be washed away by the water flow. To limit this wash out, a geotextile should always be placed behind a gabion structure in this environment. The geotextile stops the fine soil particles from being washed through the gabion unit where they are lost downstream. It is also recommended on dry structures to stop fine particles from moving through the unit