An Integrated Framework for the Assessment of Meso‐Scale Physical Habitats in Gravel‐Bed Rivers Using Remote Sensing and <scp>2D</scp> Hydraulic Modeling

ABSTRACT The use of eco‐hydraulic physical habitat models at the meso‐scale for river management and restoration design has grown in recent years. Consolidated approaches mostly rely on extensive field data collection to describe species‐ and life stage‐relevant environmental characteristics to assess habitat suitability. This restricts their applicability to smaller wadable rivers and short reaches representative of the hydro‐morphological conditions of the longer section. It also makes their use challenging in rivers subject to limited flow variability or when channel morphology changes during the data collection period. To address these limitations, complementary approaches involving remote sensing and hydraulic modeling are increasingly used alongside field methods. However, a review of the potential offered by these rapidly evolving methods is lacking, with the related gap in the availability of unified, integrated mesohabitat modeling frameworks. Here, we comprehensively review the state‐of‐the‐art of a wide set of remote sensing‐based techniques and methods used to process outputs of 2D hydraulic models for mesoscale habitat modeling in the wet channel, with a focus on gravel‐bed rivers. Based on that, we conceptualize a general and flexible 5‐step framework for integrating these complementary methods into mesoscale habitat assessment and illustrate its application with reference to the Aurino River (NE Italy). The outcomes of the literature review provide an overview of the present potential and limitations of the examined techniques, supporting the choice of which specific methods can be effectively adopted within each framework step given the specific conditions of the river of interest for a certain application.