The Science of Global Hydrology: Lessons from the U.S. Northeast Corridor

The water cycle figures prominently in the study of global change and creates an important integrating theme for current and future studies of the Earth system. In addition to greenhouse warming and concerns about an accelerated hydrologic cycle, several other anthropogenic factors interact with the water cycle directly and modify the physics, chemistry, biology, and social systems associated with fresh water. Prominent among these factors are widespread land cover change, urbanization, industrial activities, plus a host of hydraulic engineering schemes that optimize water resource access and use, including dam and reservoir construction, irrigated agriculture, and interbasin transfers. These factors yield a broad spectrum of impact, distorting natural river flow and thermal regimes, polluting fresh water, destroying aquatic habitat, and creating substantial challenges to the sustainability of inland aquatic ecosystems. A rich history of research at the local scale already demonstrates these impacts clearly.
Evidence now shows that humans are rapidly embedding themselves into the basic character of the water cycle over much broader domains—from inland environments to the coast and beyond. Yet the collective significance of such a transformation of a basic building block in the Earth system remains an open question. This presentation centralizes the role of hydrology in human history. It contends that examining the history of human-water interactions provides new ways of understanding subjects of perennial historical interest, such as patterns of human settlement, resource use, agricultural development, and urbanization. Historical hydrology also provides a means by which scientist and policy makers can more accurately predict future changes to the global water cycle. This presentation examines the U.S. Northeast hydrosystem, demonstrating the ways it is emblematic of changes that have and are taking place worldwide.