PhD student Yufang Ni
Supervised by Stuart Lane
Many rivers are heavily impacted by human activities such as the constructions of dams and sluice gates, water abstraction. These alternations not only impact significantly the morphological evolution of the river channels but also fluvial ecosystems (Bakker et al., 2018; Gabbud and Lane, 2016; Huang et al., 2015; Johnson et al., 2009; Leal et al., 2016; Munoz et al., 2018).
Water flow, sediment transport, morphological evolution and ecological processes in river systems are strongly coupled. Fluvial flows often induce sediment transport and morphological evolution, which in turn modify river flow depths and velocities (Cao et al., 2017). On the other hand, river and floodplain ecosystems are driven by the flow and sediment regimes as well as morphology, while they also have feedback effects on morphological evolution (Bätz et al., 2016; Fagherazzi et al., 2012; Gabbud and Lane, 2016).
Notwithstanding the conceptual models that are often used to describe the coupled evolution of geomorphology and ecology (Fagherazzi et al., 2012; Lane et al., 2016), quantified investigations can only be achieved by physically based numerical models. However, most numerical models (Temmerman et al., 2005; Kirwan and Murray, 2008; Marjoribanks et al., 2017) overlook a critical element of vegetation development in streams, the functions related to biofilms which stabilize sediment and begin to increase sediment weathering rates, so initiating ecosystem succession and vegetation development. In fact, biofilms are recognized as “ecosystem engineers” in river-floodplain systems (Miller and Lane, 2019) through their functional role in transforming the stream environment.
The objectives of this project are: (1) to develop a 3D model with OpenFoam that can describe the coupled processes of sediment transport, morphological change and vegetation development in alluvial rivers; (2) to assess the impacts of biofilms upon stream morphodynamics under different controlling parameters (stream slope, bed sediment, discharge, human impacts) by a case study of Turtmann river, Rhone, Switzerland.
References
Bakker, M., Costa, A., Silva, T. A., Stutenbecker, L., Girardclos, S., Loizeau, J.-L.,…, Lane, S. N. (2018). Combined flow abstraction and climate change impacts on an aggrading Alpine river. Water Resources Research, 54, 223–242.
Bätz, N., Colombini, P., Cherubini, P., Lane, S. N. (2016). Groundwater controls on biogeomorphic succession and river channel morphodynamics. Journal of Geophysical Research: Earth Surface, 121, 1763-1785.
Cao, Z., Xia, C., Pender, G., Liu, Q. (2017). Shallow water hydro-sediment- morphodynamic equations for fluvial processes. Journal of Hydraulic Engineering, 143, 02517001.
Fagherazzi, S., Kirwan, M. L., Mudd, S. M., Guntenspergen, G. R., Temmerman, S., D’Alpaos, A., …, Clough, J. (2012). Numerical models of salt marsh evolution: Ecological, geomorphic, and climatic factors. Reviews of Geophysics, 50, RG1002.
Gabbud C., Lane S. N. (2016). Ecosystem impacts of Alpine water intakes for hydropower: the challenge of sediment management. WIREs Water, 3, 41-61.
Huang, Y., Salama, M. S., Krol, M. S., Su, Z., Hoekstra, A. Y., Zeng, Y., Zhou, Y. (2015). Estimation of human-induced changes in terrestrial water storage through integration of GRACE satellite detection and hydrological modeling: A case study of the Yangtze River basin. Water Resources Research, 51, 8494-8516.
Johnson A. C., Acreman, M. C., Dunbar, M. J., Feist, S. W., Giacomello, A. M., Gozlan, R. E., …, Williams, R. J. (2009). The British river of the future: How climate change and human activity might affect two contrasting river ecosystem in England. Science of the Total Environment, 407, 4787-4798.
Kirwan, M. L., Murray, A. B. (2008). Ecological and morphological response of brackish tidal marshland to the next century of sea level rise: Westham Island, British Columbia. Global and Planetary Change, 60, 471-486.
Lane, S. N., Borgeaud, L., Vittoz, P. (2016). Emergent geomorphic-vegetation interactions on a subalpine alluvial fan. Earth Surface Processes and Landforms, 41, 72-86.
Leal, C. G., Paulo, S. P., Gardner, T. A., Leitao, R. P., Hughes, R. M., Kaufmann, P. R., …, Barlow, J. (2016). Multi-scale assessment of human-induced changes to Amazonian instream habitats. Landscape Ecology, 31, 1725-1745.
Marjoribanks, T. I., Hardy, R. J., Lane, S. N., Tancock, M. J. (2017). Patch-scale representation of vegetation within hydraulic models. Earth Surface Processes and Landforms, 42, 699-710.
Miller, H. R., Lane, S. N. (2019). Biogeomorphic feedbacks and the ecosystem engineering of recently deglaciated terrain. Progress in Physical Geography: Earth and Environment, 43, 24-45.
Munoz, S. E., Giosan, L., Therrell, M. D., Remo, J. W. F., Shen, Z., Sullivan, R. M., …., Donnelly, J. P. (2018). Climate control of Mississippi River flood hazard amplified by river engineering. Nature, 556, 95-98.
Temmerman, S., Bouma, T. J., Govers, G., Wang, Z. B., De Vries, M. B., Herman, P. M. J. (2005). Impact of vegetation on flow routing and sedimentation patterns: Three-dimensional modeling for a tidal marsh. Journal of Geophysical Research, 110, F04019.