There is a variety of potential applications for geotextiles in dams. The most common uses of geotextiles in embankment dams in the U. S. are: as a riprap filter placed on the upstream slope or in a downstream discharge area, as a riprap filter used to line watercourses, or as a filter in a downstream trench drain (often remedial work after construction).
Less common embankment dam applications include: as a protective layer and drain placed in contact with an upstream waterproofing geomembrane, as an internal filter, and as an internal drain.
Internal drains and filters are the most controversial. The applications shown in Figure 1 are not intended to define acceptable uses but to describe some of the potential uses that are contemplated, for the purposes of this article (most of these have been used and are in existence).