Erosion Control Products

The above photo shows a sand/cement bag retaining wall under construction. The white colored material between the sand/cement bags and the soil is "geotextile fabric" (filter fabric) and is used to help in the prevention of soil loss from behind retaining walls. It allows water to pass through the (porous) fabric into the cracks between the sand/cement bags while retaining the soil behind the wall. It is available in woven and non-woven types with various other specifications for many different applications.
Another typical use of the material is in the construction and maintenance of roads.

See the results of not using a geotextile fabric. See photo