below the water table, pores are filled with water Bachmann, J. & van Der Ploeg, R. R. A review on recent developments in soil water retention theory: interfacial tension and temperature effects.

The capacity of soil to regulate the terrestrial freshwater supply is a fundamental ecosystem service. Water percolating through soil is filtered, stored for plant utilization, and redistributed ...

One possible option is bioremediation, or the use of naturally occurring microorganisms (such as fungus and bacteria) that can "eat" pollutants, including those found in soil and the water table.