Horizontal strips or shelves of material built contiguous to the base of either side of levee embankments for the purpose of providing protection from underseepage and erosion, thereby increasing the stability of the embankment or reducing seepage
Department of Homeland Security, Federal Emergency Management Agency (FEMA), Levees: Identifying the Risk, Glossary: Frequently Used Terms for Levee Systems, Washington DC, USA 2008. http://www.fema.gov/media-library-data/20130726-15 54-20490-4604/lv_gloss.pdf, (Dam Sfty - Amer) {892}