HYDROGEOLOGY IN NORTH AMERICA: PAST AND FUTURE

Hydrogeology seeks to understand the earth from the pores of soils and rocks, by following water as it moves. Over the past two centuries, hydrogeology has grown in North America through contributions from many fields, geology, geophysics, geochemistry, hydrology, soil science, soil mechanics, petroleum engineering, and so on. A reasonable grasp now exists of the physical, chemical and biological processes that govern the occurrence of diverse hydrogeological systems from hydrothermal mineralization to triggered earthquakes, to sustenance of wetlands. As a historical science, hydrogeology continues to inform as to why things are the way they are, through observations of great sophistication. The latter half of the twentieth century witnessed a strong effort among some hydrogeologists to predict earth systems behavior through quantification, aided by computing machines. With increased observational lore, the complexity of hydrogeological systems in terms of spatial and temporal scales, coupled processes, and unknown forcing functions have become apparent. Extrapolation from history, prediction and control are coming to be recognized as extremely difficult or even impossible. While curiosity-driven studies will continue indefinitely, the future of hydrogeology will largely be molded by the challenges of sustainable, civilized living in a finite earth stressed by technological growth and burgeoning population. Hydrogeology will likely evolve towards considering itself to be a component, along with other earth science disciplines, of a larger whole, the delicately interlinked hydrological, erosional, and nutrient cycles on which all living communities depend for their sustenance. As human societies learn to adapt to the earth’s finiteness and its uncertain forcing functions, monitoring of earth systems so as to foresee environmental damages in a timely way will become important. In this way, the role of hydeogeology as a historical science will return to focus. As far as new hydrogeological knowledge is concerned, two areas appear promising: hydrogeology of submarine systems and the oceanic crust, and the relationships between groundwater and ecosystems.