Watershed Ecohydrology: How Do Vegetation Patterns and Climate Affect Watershed Storage and Connectivity?

Abstract:

Topography and soils have long been recognized as mediators of runoff source areas, but the effect of vegetation patterns on subsurface throughflow is less well understood. While numerous studies have shown that vegetation removal generally leads to increases in streamflow, few studies have examined the intersection between patterns of evapotranspiration and topographically driven patterns of throughflow generation and connectivity. We applied a parsimonious but spatially distributed watershed modeling framework (WECOH: Watershed ECOHydrology Model) to a snow dominated watershed in central Montana to elucidate how different vegetation scenarios and climate forcing can affect the temporal evolution of storage distributions and watershed connectivity. We derived spatially distributed snowmelt and rainfall input from two NRCS SNOTEL sites located in the experimental watershed and actual evapotranspiration from a co-located eddy-covariance tower. We generated different vegetation scenarios to simulate forest harvesting and compared streamflow response, spatial distribution of storage, and runoff source areas across scenarios. Our work aims at better understanding how the intersection of vegetation and topography mediates hydrologic response.