The central questions of karst hydrology concern (1) recharge, storage, and flow of groundwater in contemporary aquifers, (2) identification of geologic constraints on groundwater storage and flow paths, and (3) understanding of how aquifers evolve through time and the relation of this evolution to the evolution of interconnected surface-water basins. Karst aquifers generally display matrix, fracture, and conduit permeability with contrasts in effective hydraulic conductivity of many orders of magnitude. Dispersed recharge into the matrix and fracture permeability provides most of the storage and a slow-response flow system, while point recharge into the conduit system provides quick flow and little...