Underseepage 2 : The upward pressure on the land behind a levee system that is exerted by groundwater, under pressure from the flooding source, when the elevation of the floodwaters are higher than the elevation of the land
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}