GROUNDWATER RESOURCE SUSTAINABILITY: CONCEPTUAL EVOLUTION, OPPORTUNITIES, & CHALLENGES

Water resource sustainability requires rates and methods of resource utilization that can support a reasonable human population indefinitely at an acceptable standard of living and maintain an acceptable environment. BUT what is a reasonable population, an acceptable standard of living, and an acceptable environment? Have we already passed reasonable population levels? How much environmental degradation can we tolerate and what environment are we to preserve and for whom or what? Hydrogeologists understand the variability of Earth properties and the difficulty of “remediating” past mistakes; that the Earth is continually evolving, not static; that the environment that we observe is a “snapshot” at a moving target; and that we cannot maintain the environment of today or a century past, even if human activities cease. All water resources are to some extent limited and their development itself affects the safe yield, one of the initial concepts in groundwater management. The safe yield concept has evolved since first promulgated, but it is not sustainable. To achieve sustainability, we must match the stakeholders’ needs/desires (the consensus yield) with the ability to produce and deliver water (the effective yield) and the stakeholders must define mutually acceptable goals. Major challenges are: 1) applying hydrogeologic knowledge to the temporal and spatial scales of human development; and 2) developing adequate bases to assess and communicate the effects of human activities. Challenges include changes to the hydrologic cycle from climate change and human factors (e.g., urbanization, population shifts, etc.) and predicting future technological advances (e.g., environmentally and economically acceptable desalination) that could have dramatic effects on the sustainable groundwater use of our groundwater resources. The challenges are daunting, but good science and management can address them.