Meeting the Challenges of Ground Water Sustainability
Ground water scientists have developed an expanding capability to address issues associated with the development and sustainability of ground water resources. Early efforts focused on methods of evaluating the effects of ground water pumping on an aquifer's long-term capacity to yield water to wells. Subsequently, methods were applied to evaluate various effects of ground water development on surface water bodies, land subsidence and saltwater intrusion. Starting in the late 1970s, increasing concerns about contamination of ground water by human activities led to an awareness of the great difficulty and expense of cleaning up contaminated aquifers and drew attention to the importance of prevention of ground water contamination. With time, it has become clear that the chemical, biological and physical aspects of ground water systems are interrelated and require an integrated analysis, and that many issues involving the quantity, quality and ecological aspects of surface water are interrelated with ground water. Thus, ground water hydrologists continually are challenged by the need to provide greater refinement to their analyses and to address new problems and issues as they arise.
Computer simulation models have value beyond their use as purely predictive tools. They commonly are used as learning tools to identify additional data that are required to better define and understand ground water systems. Furthermore, computer simulation models have the capability to test and quantify the consequences of various errors and uncertainties in the information necessary to determine cause and effect relationships and related model-based forecasts. This capability, particularly as it relates to forecasts, may be the most important aspect of computer models in that information about the uncertainty of model forecasts can be defined, which in turn enables water managers to evaluate the significance, and possibly unexpected consequences, of their decisions.