Satellite Remote Sensing of Global River Delta Shoreline Mobility and their Relationship to Fluvial Sediment Fluxes

Anthropogenic activities in river basins (e.g. land use changes, mining, damming), have significantly altered riverine sediment flux resulting in shifts in river delta shorelines, and subsequent changes to deltaic land mass. Understanding changes to the river deltaic shoreline is important to identify vulnerable areas on the delta and install coastal defense structures, plan engineering structures for transport, and land reclamation/zoning works in accordance with sustainable deltaic land management. The overarching goal of this study was to identify temporal trends of sediment fluxes (i.e. suspended, bedload and suspended bed-material) to river deltas, and their effects on shoreline movement of 30 global river deltas between 1978-2018. We use a global-scale riverine modeling framework (WBMsed) to investigate sediment fluxes to river deltas over time. Landsat satellite imagery are used to extract shorelines of river deltas during 5 historical time steps to derive shoreline positions. Rates of shoreline migration and other accretion/erosion statistics are calculated using the Digital Shoreline Analysis System (USGS). We provide (a) for the first time in literature, quantitative understandings and long-term trends of sediment fluxes to river deltas, (b) quantitative understandings of historical migration rates and ancillary shoreline migration statistics of well-curated shorelines of global deltas, and (c) link relationships between sediment fluxes and shoreline mobility provides useful baselines and directions to researchers regarding comparative studies that will further solidify our understanding of sediment-driven shoreline migration. The outcomes of this study yield several novel insights into decadal relationships between sediment fluxes and shoreline mobility, transform our analytical capabilities for studying human influences on river deltas, globally, and also provide a platform to better estimating incoming fluxes to river deltas, large scale flux modeling endeavors, erosion/accretion in different parts of the deltaic land-sea interface, and zonal planning operations for long-term sustainability of deltas.