Contaminated and Hazardous
Waste Site Management
The estimated quantity by which an observed or calculated value may depart from
the true value.
Conditions in which the upper surface of the zone of saturation forms a water
table under atmospheric pressure.
Aquifer: An aquifer in which there are no confining beds between the capillary
fringe and land surface, and where the top of the saturated zone (the water table)
is at atmospheric pressure.
Deposits: Deposits overlying bedrock and consisting of soil, silt, sand, gravel
and other material which have either been formed in place or have been transported
in from elsewhere.
Material: Naturally occurring geologic material that has not been lithified into
Zone: The zone between the land surface and the water table. It includes the root
zone intermediate zone, and capillary fringe. The pore spaces contain water, as
well as air and other gases at less than atmospheric pressure. Saturated bodies,
such as perched groundwater, may exist in the unsaturated zone, and water pressure
within these may be greater than atmospheric. Also known as "vadose zone."
Upward movement of salty or brackish groundwater into wells and into aquifers
previously occupied by fresh or less mineralized groundwater.
An upward hydrologic slope; that defines areas that are higher than contaminated
areas and, therefore, are not prone to contamination by the movement of polluted
Corridor/Trenches: A subsurface trench in which pipes, electrical lines, etc.
are placed. It is usually filled with coarse material and so may be much more
permeable than the surrounding material.