Groundwater

Set of regulations and measures taken to protect groundwater resources.

Risk of infiltration of pollutants from the surface, through the soil and unsaturated zone. The vulnerability of aquifers is intrinsic: it depends on the topographic (ground slope), pedological (permeability), geological context (permeability, thickness). A confined aquifer, covered by a low permeability formation (often clays) is not very vulnerable as compared to an unconfined aquifer.

Water that comes naturally out of the ground, or by metonymy the point where this water rushes out. The spring is often the headwaters of a watercourse, but springs can feed ponds or lakes or flow directly into the sea, or produce water that disappears again into the ground.

Stream passing through a very large cavity (e.g. a cave or a cavern) or a set of large communicating cavities.

Stream whose water comes mainly from the aquifer it drains.

Corrective action to improve the quality of groundwater.

Rising of the groundwater level or of the piezometric surface due to a recharge after depletion.

A branch of hydraulics that mathematically studies the natural gravity flow (of an aquifer) or the induced flow (by drainage or pumping, for example) of free groundwater in permeable media, under the effect of a hydraulic or pressure gradient.

Action to remove pollution from groundwater. Water decontamination can use different approaches (physical, chemical or biological), in situ (directly underground) or ex situ (water pumping, treatment and reinjection).