Theoretical and Applied Framework of River Geophysics

Abstract: Rivers and their adjoining catchments form interconnected physical systems comprising river water, groundwater, soils, rock formations, and riverbanks. Stage fluctuations, bank erosion, unsaturated infiltration, and flood propagation occur across different spatial scales, making it difficult to distinguish underlying mechanisms using a single observation type or parameter set. This review examines representative processes, measurable quantities, and observational approaches at three terrestrial scales: the channel-riverbank, hillslope-vadose zone, and catchment-river network. It compares the contributions and limitations of studies on river-groundwater exchange, near-surface geophysical monitoring, conceptual hydrological modelling, and uncertainty analysis, and distinguishes measured properties from effective model parameters. Ancient Martian channels and water-/ice-related landforms are also considered as potential comparative targets, not as evidence that terrestrial hydrological mechanisms can be transferred directly to other planets. A framework linking phenomenon identification, joint observation, mechanism-based modelling, uncertainty assessment, and independent validation is then summarized. This perspective supports testable cross-scale interpretation and may inform bank protection, flood-risk assessment, and monitoring design; practical benefits require independent field and cross-event evaluation. Keywords: River geophysics, river-groundwater exchange, unsaturated flow, planetary river geophysics © International Journal of Ground Sediment & Water, © Sun Jichao, The website is Web1: https://ijgsw.eu.org/ Web2: https://ijgsw.net/