aquifer - a body of permeable rock that can contain or transmit groundwater.

carbonate rock - a class of sedimentary rocks composed primarily of carbonate minerals. The two major types are limestone and dolostone.

fracture - any kind of separation or break in a rock formation that divides the rock into two or more pieces.  They are usually generated when the rock is not strong enough to hold up under intense stress.

groundwater - water held underground in the soil or in pores and crevices in rock (compare with 'surface water').

infiltration - permeation of a liquid into something by filtration.

karst geology - a subsurface composed of limestone that has been eroded by dissolution, producing ridges, towers, fissures, sinkholes, and other characteristic forms.

non-point source pollution - pollution that comes from many diffuse sources. Generally caused by rainfall or snowmelt moving over and through the ground (compare with 'point source pollution'.

percolation - see 'infiltration'

point-source pollution - any single, identifiable source of pollution from which pollutants are discharged, such as a pipe, ditch, ship or factory smokestack (compare with 'non-point source pollution').

source water - water that provides for public drinking water supplies and private water wells.

surface water - water that collects on the surface of the ground (compare with 'groundwater').