COLLABORATIVE RESEARCH: The intersection of vegetation organization and watershed topology: Ecohydrologic imprints in runoff generation and stream discharge

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COLLABORATIVE RESEARCH: The intersection of vegetation organization and watershed topology: Ecohydrologic imprints in runoff generation and stream dischargeRyan E. Emanuel, Appalachian State UniversityBrian L. McGlynn, Montana State UniversityAbstractThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). Vegetation plays a key, though complex role in the water balances of terrestrial landscapes. One aspect contributing to this complexity is the spatial heterogeneity of vegetation. In particular, the effects of the spatial distribution of vegetation on runoff processes at hillslope and watershed scales remain poorly understood, due in large part to the variety of spatial relationships between landforms and vegetation within and among terrestrial landscapes combined with spatially and temporally variable evaporation and transpiration. This research project will develop a conceptual framework that considers vegetation as a temporally dynamic and spatially heterogeneous control on runoff generation and stream discharge within hillslope and watershed networks. The framework will be tested using a combination of intensive field-based measurements, airborne light detection and ranging (LIDAR) measurements, and numerical simulations of coupled hydrological and ecophysiological processes. Small (approximately 500 ha) watersheds in the northern Rocky Mountains of Montana and the southern Appalachian Mountains of North Carolina will serve as field sites instrumented with stream gages, piezometers, and weather stations to detect shallow groundwater and stream discharge responses to vegetation activity (i.e. transpiration in response to meteorological conditions) and vegetation heterogeneity (i.e. different vegetation distributions and characteristics among hillslopes and watersheds). LIDAR will be used to assess the distribution of vegetation within hillslopes and watershed networks, providing empirical evidence for the sensitivity of hydrological processes to the spatial arrangement of vegetation at these scales. Numerical modeling will provide understanding of the roles of biological and physical processes, within the constraints of the algorithms coded into the model, in the observed hydrological responses, both within and among watersheds. By comparing hillslopes and watersheds from two different biogeographical and climatological regions, this project will result in a more generalized understanding of how vegetation affects hydrological processes at these scales, addressing an area of critical research need at the interdisciplinary interface of watershed hydrology and vegetation ecophysiology. Broader impacts of this project include promoting research in a predominantly undergraduate institution, training future scientists, strengthening collaborations between research intensive and predominantly undergraduate institutions, advancing research for an early-career scientist and diversifying participation in the earth sciences. During the course of this project, the PIs will also develop and teach a collaborative, field-based course for students from both Appalachian State University (ASU) and Montana State University (MSU). Additionally, the research project will increase participation of underrepresented populations in the sciences. Both PIs are directly involved in programs to provide research opportunities and mentoring to underrepresented populations, including the American Indian Research Opportunities program at MSU and the Faculty Fellows program at ASU. The project will directly involve two faculty members, one Ph.D. student, two undergraduate researchers, and approximately twenty course enrollees from both institutions.