Understanding streambeds as complex systems: review of multiple interacting environmental processes influencing streambe
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Aquatic Sciences
OVERVIEW ARTICLE
Understanding streambeds as complex systems: review of multiple interacting environmental processes influencing streambed permeability Shivansh Shrivastava1 · Michael J. Stewardson1 · Meenakshi Arora1 Received: 5 February 2020 / Accepted: 10 July 2020 © Springer Nature Switzerland AG 2020
Abstract The permeability of sediments at the sediment–water interface is an important control on several stream ecosystem services. It is well known that streambed permeability varies over several orders of magnitude, however, the environmental processes influencing this variation have received little attention. This review synthesizes the state-of-art knowledge and gaps in our understanding of the key physical and biological processes which can potentially modify the streambed permeability. These processes include—(a) physical clogging due to fine sediments, (b) biological clogging due to microbial biomass, and (c) sediment reworking by in-stream fauna. We highlight that the role of biotic processes (bioclogging and sediment reworking processes) in modifying the streambed permeability has not been investigated in detail. We emphasize that complex feedback mechanisms exist between these abiotic and biotic processes, and an interdisciplinary framework is necessary to achieve a holistic understanding of the spatio-temporal variability in streambed permeability. To this end, we propose to develop a conceptual model for streambed evolution after a disturbance (e.g. floods) as this model could be valuable in comprehending the dynamics of permeability. We also outline the challenges associated with developing a widely applicable streambed evolution model. Nonetheless, as a way forward, we present a possible scenario for the evolution of a streambed following a high flow event based on the trajectory of responses of the above-mentioned environmental processes. Finally, we suggest future research directions that could assist in improving the fundamental understanding of the clogging and sediment reworking processes and consequently of the dynamics of streambed permeability. Keywords Streambed permeability · Fine sediment clogging · Bioclogging · Sediment reworking · Hyporheic zones · Streambed evolution
Introduction The hyporheic zone is recognized as a unique ecotone supporting diverse hydrological, biogeochemical, and ecological stream functions (Boano et al. 2014; Lewandowski et al. 2019). Several definitions of hyporheic zones are present in * Shivansh Shrivastava [email protected] Michael J. Stewardson [email protected] Meenakshi Arora [email protected] 1
Environmental Hydrology and Water Resources Group, Department of Infrastructure Engineering, The University of Melbourne, Parkville, VIC 3010, Australia
the literature (Lewandowski et al. 2019), and for this work, the hyporheic zone is considered as a zone of saturated sediments lying below and adjacent to the streambed where surface water seeps into the bed, may mix with groundwater and re-emerges into the stream (Brunk
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