What is “perched groundwater?
A. “Perched groundwater” is a zone of saturation in a formation that is discontinuous from the water table and the unsaturated zones surrounding this formation. The formation exists as a discrete saturated zone that may be ephemeral (in direct response to precipitation in the immediate vicinity) or recharged by percolation from nearby surface water or other perched water zones. The hydrogeologic investigation, supplemented by published reports and/or hydrogeologic investigations at adjacent facilities, should document that the stated condition exists, and that there isnt any hydraulic communication with other aquifer(s), exposure pathways or receptors. (NOTE: Permeable backfill, e.g., in buried utility trenches, may create a preferential pathway that could act as a transport mechanism to affect a receptor.) Perched groundwater may be a source of potable groundwater.
A. “Perched groundwater” is a zone of saturation in a formation that is discontinuous from the water table and the unsaturated zones surrounding this formation. The formation exists as a discrete saturated zone that may be ephemeral (in direct response to precipitation in the immediate vicinity) or recharged by percolation from nearby surface water or other perched water zones. The hydrogeologic investigation, supplemented by published reports and/or hydrogeologic investigations at adjacent facilities, should document that the stated condition exists, and that there isn’t any hydraulic communication with other aquifer(s), exposure pathways or receptors. (NOTE: Permeable backfill, e.g., in buried utility trenches, may create a preferential pathway that could act as a transport mechanism to affect a receptor.) Perched groundwater may be a source of potable groundwater.
