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Publication Date
4 April 2023

Delta Shoreline Metrics Link Form to Process

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It has long been hypothesized that delta morphology and its evolution are primarily dictated by the interplay of three primary forcings: riverine, wave, and tidal. We used three process-informed, geometric, and spectral metrics to characterize multiscale shoreline features that all can be readily extracted from widely available satellite imagery. Our unsupervised clustering of delta shoreline metrics revealed five distinct delta morphotypes which correspond to distinct forcings.


Our method provides an unsubjective and reproducible set of measurements that allow for the classification of deltas based on the relative influences of the primary driving forces. The work expands on prior qualitative classification efforts. It provides a framework to understand how shifts in the driving forces may result in changes in delta morphology.


We have introduced a novel quantitative framework to classify river delta morphology based on a multiscale characterization of delta shoreline structure through geometric and spectral metrics which form a three-dimensional Shoreline Morphometric Space. These metrics allow for the linking of delta morphology to process-based drivers. By linking form to process, our method allows for evaluating dominant controls on delta based on easily measurable metrics even for river systems where process-based data is scarce. We show that the dominant forcings inferred from shoreline structure generally align with those estimated via relative sediment fluxes, while positing that misalignments arise from spatiotemporal heterogeneity in deltaic sediment fluxes not captured in their estimates. The proposed framework for shoreline characterization advances our quantitative understanding of how shoreline features reflect delta forcings, and may aid in deciphering paleoclimate from images of ancient deposits and projecting delta morphologic response to changes in sediment fluxes.

Point of Contact
Joel Rowland
Los Alamos National Laboratory (LANL)
University of California Irvine (UC Irvine)
Funding Program Area(s)
River Delta Morphotypes Emerge From Multiscale Characterization of Shorelines
Vulis, L., A. Tejedor, H. Ma, J. H. Nienhuis, C. M. Broaddus, J. Brown, D. A. Edmonds, J. C. Rowland, and E. Foufoula‐Georgiou. 2023. “River Delta Morphotypes Emerge From Multiscale Characterization Of Shorelines”. Geophysical Research Letters 50 (7). American Geophysical Union (AGU). doi:10.1029/2022gl102684.