ABSTRACT
A r id it y in c l im a t e terms relates principally to paucity of precipitation, which in turn dictates the opportunity for groundwater recharge and the sustainability of naturally occurring groundwater resources. The sporadic distributions, frequencies, intensities, and amounts of precipi tation that characterize the very low precipitation areas of the world inherently constrain recharge opportunity and, coupled with ground conditions, result in very complex and little-understood recharge pro cesses. Ambient soil moisture concentrations are normally very small such that recharge directly from precipitation through the soil profile (Figure 1, pathway D), as seen under persistently higher precipitation conditions, does not occur. Recharge can occur indirectly through a variety of mechanisms in amounts, however, that may not be significant in resources terms (Figure 1, pathways A, B and C).
