CAREER: Linking hydrological processes and landscape form to the riverine thermal regime in the Mid-Atlantic US

River temperature is a crucial measure of water quality and stream health. It is influenced by many different factors, such as watershed characteristics, weather conditions, and processes of the water cycle. However, more work is needed to understand how processes, such as streamflow, groundwater discharge, and evapotranspiration, impact the magnitudes of river temperature throughout the year. With a particular focus on sites in the Mid-Atlantic region, this project will approach the issue of river temperature in two ways. First, through a framework development and timeseries analysis of river temperature observations, and second, by using models that describe water movement and energy exchange. Clarifying the role of hydrology in determining stream temperature is needed to understand how average conditions as well as extreme conditions such as droughts may impact water quality, and to identify places that are most susceptible to such impacts. Through these research activities, the researcher will provide undergraduate training and mentoring to enhance skill development and career preparedness and will support visiting graduate research scholars to coach as undergraduate research mentors while allowing them to learn about a career at a primarily undergraduate institution. Findings will be shared with the public and through K12 educational activities in partnership with a local environmental education center. The overall objective of the research is to conceptually, empirically, and predictively link stream temperature and hydrologic processes in complex environments along the river network. To improve understanding of how changes to hydro-climatology propagate into streamflow and water quality, this work will integrate observations from the reach to regional scale, enabling systematic synthesis of relationships between river network controls and stream temperatures. The project will identify empirical relationships between static and dynamic descriptors of hydrological processes and thermal signatures, metrics extracted from timeseries of stream temperature, of Mid-Atlantic US stream sites, and will quantify the impact of varying hydrological and meteorological controls on river temperature within a deterministic stream temperature modeling framework. This empirical approach will be balanced with physically based modeling of local stream temperatures at the reach to watershed scale to improve understanding of how variations in and interactions among hydrological processes, meteorological variables, and landscape characteristics along the river network may influence downstream river temperature. Altogether, this research will yield new insights on the empirical and mechanistic controls on river temperature regimes and the importance of hydrological processes to these regimes, while equally supporting the training of undergraduate and graduate researchers as well as public outreach and education. This project is jointly funded by the Hydrologic Sciences program, and the EAR Education and Broadening Participation program. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.