As a hydrologist, my research explores how natural and anthropogenic factors affect water -- in streams, lakes, aquifers, rivers, and estuaries. Understanding processes that affect status and trends of water quality remains a grand challenge; given the need to represent elemental cycles within diverse landscapes, and to characterize spatial and temporal variability. I approach this from an interdisciplinary perspective, and have worked with over 300 collaborators from around the world on my publications about watersheds and water resources. My work contributes toward a scientific basis for management programs and policies to mitigate the effects of pollution; and to protect, conserve, and restore surface waters. Toward communicating scientific information, I regularly participate in conferences and public events, provide scientific perspectives, and make Congressional visits. I am currently a member of several committees of EPA's Science Advisory Board dealing with air and water quality; serve on the Board of Directors of the Universities Council on Water Resources and the Consortium of Universities for the Advancement of Hydrological Sciences; and lead one of the Centers comprising the National Institutes of Water Resources.
Coupled hydrological, ecological, & biogeochemical processes that affect streamflow and water quality; design of land management programs & policies to mitigate the effects of pollution, and to protect, conserve, and restore surface waters.