Evaluating the Stability of Headwater Reference Catchments from Long-Term Paired Watershed Studies: an Eastern Perspective.

Reference catchments are experimental watersheds in which direct anthropogenic activities have been reduced or completely eliminated over long periods of time. Reference catchments studies have greatly contributed to the advancement of hydrology science since the first half of the last century. This research looks at novel approaches to define the function of reference watersheds by combining the great amount of data available from reference catchments, and modern theoretical frameworks. Reference catchments play a critical role in experimental hydrology by providing a landscape-scale baseline of hydrologic conditions in the absence of disturbance. Reference catchments are assumed to be hydrologically stable overtime, yet climate and forest ecosystems are dynamic. This study tests the assumption of hydrologic stability of reference catchments by investigating long terms climate and hydrometric records of multiple headwater reference catchment across classic eastern US paired catchment studies of the Fernow (WV), Hubbard Brook (NH), and Coweeta (NC). A simple water and energy balance model based on the Budyko framework is used to quantify rainfall partitioning into runoff and evaporation and to quantify runoff sensitivity to changes in climate and catchment properties. Furthermore, our modeling approach is used to separate climate and land surface drivers to quantify dominant drivers of long-term change.