Monitoring the response of arid zone hydrology to environmental change by means of the stable isotope composition of groundwaters

The formation of groundwaters under an arid climate is extremely sensitive to any environmental change and, in particular, to changes in the pattern of land usage, the vegetation cover and the surface morphology. Such changes can result from climatic change on a global scale or from local anthropogenic causes through agricultural development or urbanization. The anthropogenic effect on the process of groundwater formation is a function of the scale of operation. On a small scale, water is used up and diverted from recharge pathways. However, large scale agricultural or urban development in the arid zone will usually enhance the rate of groundwater recharge. The changes in the hydrological mechanisms imprint a different isotopic signature on the groundwater and thus the isotope composition of the water resources can serve as a monitor of such changes. -from Author