Damming the delta: cross-border attribution of coastal-delta sediment starvation

Reproducibility package for "Damming the delta: cross-border attribution of coastal-delta sediment starvation" (Yiran Li, 2026). This archive contains the analysis code, derived data and figures underlying the paper, which presents the first global source–receptor accounting of cross-border delta sediment starvation. Local sediment production is routed along the HydroBASINS river network; each dam's trapping is computed from its Brune efficiency and regulated-flow share; natural loads are anchored to observed pre-dam values; and each delta's dam-driven deficit is separated into a domestic and a cross-border part and attributed to the upstream countries responsible. Key results: dams withhold ~5,400 Mt yr⁻¹ of sediment from the world's deltas, of which ~900 Mt yr⁻¹ (17%) crosses an international border; 37 countries are net downstream bearers; ~180 million people live on 41 deltas that lose most of their sediment to foreign dams (Ganges–Brahmaputra, Nile, Mekong, Tigris–Euphrates, and others). Leading upstream sources: India, United States, China, Ethiopia, Sudan. Contents: main model (sediment_routing.py), population overlay (pop_routing.py), table/figure generators (make_tables.py, make_figures_v6.py), manuscript and SI builders, derived CSV tables, and Figures 1–5. The README documents (i) quick reproduction of all figures and tables from the included derived data with no large downloads, and (ii) full reproduction from the public raw inputs: HydroBASINS, Global Dam Watch, BasinATLAS, GlobalDeltaData (Nienhuis et al.), Edmonds et al. (2020) delta polygons, GHS-POP R2025A, Natural Earth, and World Bank GDP. Related article: Li, Y. (2026). Damming the delta: cross-border attribution of coastal-delta sediment starvation. Journal of Environmental Management (under review). No generative-AI tools were used to produce any figure or graphical artwork; all figures are data plots generated by the included code.