FORTY YEARS OF MAKING MOUNTAINS OUT OF MOLEHILLS

This session offers the opportunity to reflect on 40 years spent enthusiastically researching hydrogeology, and earth science in general. The most striking changes I have observed, and participated in, involve the recognition of the interlinked nature of earth-science processes, effected by feedbacks from one type of process to another and one scale to another. When I started graduate school in 1976, my education was fairly well encompassed by well hydraulics, primitive numerical models of flow in aquifers, and geochemical evolution of flowing groundwater. It was as much defined by methodology as by subject matter. Today, the practical issues requiring specialized knowledge of these subjects remain, but as a field of science, hydrogeology is, at one end of the time scale, an integral part of understanding the geochemical evolution of the earth, and at the other, an integral part of understanding the earth-system response to increases in greenhouse gas concentrations over the past few decades. The relation between precipitation and groundwater flow cannot be understood without reference to vegetation ecology, but the distribution of vegetation cannot be understood without reference to groundwater flow. If hydrogeology is going to maintain an identity within the greater scientific endeavor, it is going to have to agressively push toward the points of contact with other earth-system processes, in other words, to look outward rather than looking inward.