An ecohydraulics virtual watershed: Integrating physical and biological variables to quantify aquatic habitat quality

Abstract

Advances in remote sensing coupled with numerical modelling allow us to build a “virtual ecohydraulics watershed” at the micro‐habitat scale. This approach is an integrated modelling framework with a cascade of models including physical (hydrologic, hydraulic, and stream water temperature) and biological (fish habitat) modelling at a resolution and extent important for aquatic and terrestrial organisms. We applied this approach to quantify the impacts of discharges and water temperature on habitat quality and spatial/temporal habitat use patterns of bull trout, a federally listed species along the South Fork Boise River. We coupled process‐based snow melt and hydrologic models to predict water availability within the watershed. The model fed one‐ and two‐dimensional hydrodynamic models to predict stream hydraulics and water temperature using high‐resolution (meter scale) river bathymetric data. This information was then used in an aquatic habitat modelling to characterize habitat quality distribution as a function of discharges. Our results showed that the summer thermal regime of river system would alter available habitat. The high spatial resolution analysis allows modelling to predict the importance of lateral habitats, which serve as vital refugia during high‐flow events for many fish species. The advances in remote sensing, numerical modelling, and understanding of physical‐biological processes provide us an opportunity to conceptualize new process‐based integrated modelling tools to analyse human impacts at a catchment scale, for example, dam operation and climatic variability on aquatic habitat and status, and further to develop restoration protocols in a virtual domain before field studies are developed and/or structures built.

Sensitivity of habitat hydraulic model outputs to DTM and computational mesh resolution

“…Our results share some similarities with the Moore and Gregory () findings where lateral habitats exist and are critical for specific fish species (Benjankar, Tonina, Sohrabi, & McKean, ). The existence of lateral habitats can be highlighted with the use of 2D hydraulic‐hydrodynamic models due to their capability to accurately reproduce the spatial flow patterns, especially for complex river and riverine areas (Alaska Energy Authority, ; Brown & Pasternack, ; Crowder & Diplas, ; Leclerc et al, ; Moore & Gregory, ).…”

Integrated Hydrological Modeling to Analyze the Effects of Precipitation on Surface Water and Groundwater Hydrologic Processes in a Small Watershed

“…The results emphasized the importance of the accurate input datasets (e.g., precipitation) for reliable model predictions [39,48]. The model developed in this study can be used to simulate hydrological processes in the future for the Canteen-Cahokia watershed to analyze impacts on future climate change and land cover changes due to urbanization on the hydrological process (groundwater elevations and surface water flows), and subsequent impacts on ecosystems (aquatic and riparian) and urban flooding [96,97]. This study is focused on a small watershed; therefore, further studies are required to transfer the findings to other watersheds in different geographic regions and large watersheds.…”

Reconfiguration of ecohydrology as a sustainability tool for Himalayan waterways

“…Integration of ecohydrology and ecohydraulics has benefits to improve waterways both in the use of water resources and ecosystem dynamics (Benjankar et al, 2019). Integration improves the predictive ability of how organisms will respond to environmental gradients including the different degree of hydraulic-associated flow regimes (Yao, 2021).…”