Groundwater of carbonate aquifers

Abstract Carbonate rocks, particularly limestone, comprise some of the most productive aquifers on Earth. Their relatively high transmissivity stems from the development of secondary porosity and permeability. Compared to silicate rocks, the carbonate matrix is rapidly dissolved by weak acids, particularly carbonic acid. This dissolution during infiltration and groundwater flow can result in karstification, marked by the evolution of preferential pathways along which flow becomes turbulent rather than laminar. In karst aquifers, surface and subsurface drainage are commonly integrated from sinkholes to springs via conduit networks. Groundwater velocities can approach those of surface streams and interbasin groundwater flow can occur beneath topographic divides. Consequently, solute tracers are often used to determine connectivity between recharge and discharge points in karst aquifers. Because of susceptibility to contamination and the ecological significance of cave and spring ecosystems, monitoring of flow and water quality in carbonate aquifers is particularly important.