Research

Our research explores environmental systems, often using approaches developed in physics.  Environmental systems often encompass physical processes and material properties that are complex, heterogeneous on all scales, and poorly characterized by direct measurement.  Thus we often need to try to understand these systems by cleverly analyzing how they behave, and by probing their inner workings using carefully designed experiments.  The spatial heterogeneity and process complexity of environmental systems imply that any feasible theory will inevitably involve substantial simplifications and generalizations. The essential question in environmental science is which simplifications and generalizations are the right ones.  We seek to answer questions such as:

• How does rainfall become runoff?
• How is the chemistry of natural waters shaped by subsurface transport and mixing, by chemical reactions with soils and rocks, and by biological processes?
• Conversely, what can we learn about these processes at the scale of the whole landscape, by observing the signals that they impart to streams?
• What processes control rates and patterns of physical erosion and chemical weathering? And how do they, in turn, regulate the topographic evolution of mountains and valleys, as well as the physical and chemical environment in which we (and all other organisms) live?

We explore connections between terrestrial and aquatic environments, and linkages between physical, chemical, and biological processes. Our work typically combines field observations, simple mathematical models, and novel analyses of environmental data.