Fate and transport in fluvial systems - theoretical upscaling of local processes
ND-LEEF stream (credit: Nicole Gorman)
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Carbon, nutrients, and contaminants are transformed in highly reactive regions of the stream. The overall reactivity therefore depends both on local reactivity of these regions and on the rate that reactive materials are delievered to these regions. For example, while it is relatively simple to determine whether streams are net sources or sinks of CO2, it remains extremely difficult to predict how carbon fluxes will change with changing physical (e.g,. flow, temperature) or chemical (oxygen levels) conditions. Under this theme, we combine field-scale tracer experiments, numerical experiments and analytical modeling in an effort to better predict how societally-relevant materials are transported and transformed in streams.
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Roche, K.R., Drummond, J.D. , Sund,N.L, Schumer, R., & Dentz, M. (2020). Reach-scale modeling of reaction cascades and spatially-dependent reactions in the hyporheic zone. European Geophysical Union, Vienna, Austria. (invited)
Roche, K.R.*, Shogren, A., Aubeneau, A.F., Tank, J.T., & Bolster, D. (2019). “Modeling benthic vs. hyporheic uptake in unshaded streams with varying substrates.” JGR-Biogeosciences, 124(2), 367-383.
Kim, J., Roche, K.R., Bolster, D., & Doudrick, K.* (2019). “Transport of Food- and Catalytic-Grade Titanium Dioxide Nanoparticles in Controlled Field Streams with Varying Streambed and Biofilm Conditions.” Environmental Science: Nano 6 (11), 3454-3466.
Riis, T.*, Reisinger, A.J., Aubeneau, A., Roche, K.R., et al. (2019). “Riverine macrophytes control seasonal nutrient uptake via both physical and biological pathways.” Freshw Biol., 00, 1-15.
Ward, A.S.*, et al. (2019). "Co-located contemporaneous mapping of morphological, hydrological, chemical, and biological conditions in a 5th-order mountain stream network, Oregon, USA." Earth System Science Data, 11(4), 1567-1581.
Roche, K.R.*, Shogren, A., Aubeneau, A.F., Tank, J.T., & Bolster, D. (2019). “Modeling benthic vs. hyporheic uptake in unshaded streams with varying substrates.” JGR-Biogeosciences, 124(2), 367-383.
Kim, J., Roche, K.R., Bolster, D., & Doudrick, K.* (2019). “Transport of Food- and Catalytic-Grade Titanium Dioxide Nanoparticles in Controlled Field Streams with Varying Streambed and Biofilm Conditions.” Environmental Science: Nano 6 (11), 3454-3466.
Riis, T.*, Reisinger, A.J., Aubeneau, A., Roche, K.R., et al. (2019). “Riverine macrophytes control seasonal nutrient uptake via both physical and biological pathways.” Freshw Biol., 00, 1-15.
Ward, A.S.*, et al. (2019). "Co-located contemporaneous mapping of morphological, hydrological, chemical, and biological conditions in a 5th-order mountain stream network, Oregon, USA." Earth System Science Data, 11(4), 1567-1581.
Basin-Scale Hydrologic Variability
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There is growing evidence that changing precipitation patterns are impacting not only freshwater ecosystems, but also human decisions. We are investigating the mechanistic links between changing hydrology and myriad processes at the scale of river basins. This work is primarily focused on developing analytical models based on theory of stochastic processes.
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Muller, M.F., Roche, K.R., Dralle, D. (2019) "Catchments as modulator of changing climate variability", American Geophysical Union Fall meeting, San Francisco
Roche, K.R., Müller-Itten*, M., Dralle, D., Bolster, D., & Müller, M.F.* (2020). “Climate change and the opportunity cost of conflict.” Proceedings of the National Academy of Sciences, 117 (4) 1935-1940.
Turbulent interactions between surface and ground waters
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We investigate how materials are transported across and within the hyporheic zone, a region where stream water and groundwater mixes. In energetic streams with coarse-grained beds (e.g., gravels), turbulent eddies rapidly pulse materials into the streambed, but this process is not well characterized in transport models. We conduct physical and numerical experiments to develop improved models of mass transport in streams and rivers.
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Lian, Y.P., Dallmann, J., Sonin, B., Roche, K.R., Liu, W.K., Packman, A.I., Wagner, G.J.* (2019). “Large eddy simulation of turbulent flow over and through a rough permeable bed.” Computers and Fluids, 180, 128-138.
Roche, K.R.*, Blois, G., Best, J.L., Christensen, K.T., Aubeneau, A.F., & Packman, A.I. (2018). “Turbulence links momentum and solute exchange in coarse‐grained streambeds.” Water Resources Research, 54 (Editor’s Choice Award; Featured in Eos)
Roche, K.R.*, Li, A., Bolster, D., Wagner, G., & Packman, A.I. (2019). “Effects of turbulent hyporheic mixing on reach-scale transport.” Water Resources Research, 55
Grant, S. B., Gomez‐Velez, J. D., Ghisalberti, M., Guymer, I., Boano, F., Roche, K.,R. & Harvey, J. (2020). A One‐Dimensional Model for Turbulent Mixing in the Benthic Biolayer of Stream and Coastal Sediments. Water Resources Research, e2019WR026822..
Roche, K.R.*, Blois, G., Best, J.L., Christensen, K.T., Aubeneau, A.F., & Packman, A.I. (2018). “Turbulence links momentum and solute exchange in coarse‐grained streambeds.” Water Resources Research, 54 (Editor’s Choice Award; Featured in Eos)
Roche, K.R.*, Li, A., Bolster, D., Wagner, G., & Packman, A.I. (2019). “Effects of turbulent hyporheic mixing on reach-scale transport.” Water Resources Research, 55
Grant, S. B., Gomez‐Velez, J. D., Ghisalberti, M., Guymer, I., Boano, F., Roche, K.,R. & Harvey, J. (2020). A One‐Dimensional Model for Turbulent Mixing in the Benthic Biolayer of Stream and Coastal Sediments. Water Resources Research, e2019WR026822..
Biological drivers of solute and particle transport
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Water's movement controls the habitability of any freshwater environment by delivering nutrients, redistributing contaminants, and imparting shear stresses on organisms. In turn, organisms can both directly and indirectly control the movement of mass in freshwater systems. We investigate feedbacks between hydrology and biological activity, in an effort to understand how they evolve in time and how they are sensitive to external environmental perturbations.
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Roche, K.R.*, Drummond, J.D., Boano, F., Packman, A.I., Battin, T.J., & Hunter, W.R. (2017). “Benthic Biofilm Controls on Fine Particle Dynamics in Streams.” Water Resources Research, 53, 222–236.
Aquino, T.*, Roche, K.R., Aubeneau, A.F., Packman, A.I., & Bolster, D. (2017). “A Process-based model for bioturbation-induced mixing.” Scientific Reports, 7 (1)
Roche, K.R.*, Aubeneau, A.F., Xie, M., Aquino, T., Bolster, D., & Packman, A.I. (2016). “An Integrated Experimental and Modeling Approach to Predict Sediment Mixing from Benthic Burrowing Behavior.” Environmental Science and Technology, 50 (18), 10047–10054.
Aquino, T.*, Roche, K.R., Aubeneau, A.F., Packman, A.I., & Bolster, D. (2017). “A Process-based model for bioturbation-induced mixing.” Scientific Reports, 7 (1)
Roche, K.R.*, Aubeneau, A.F., Xie, M., Aquino, T., Bolster, D., & Packman, A.I. (2016). “An Integrated Experimental and Modeling Approach to Predict Sediment Mixing from Benthic Burrowing Behavior.” Environmental Science and Technology, 50 (18), 10047–10054.
