The SWOT River Database (SWORD) is a global hydrological river network database containing 248,673 reaches, 11.1M nodes, and 66.9M centerlines across 6 continental regions (NA, SA, EU, AF, AS, OC). SWORD defines the nodes and reaches that constitute SWOT river vector data products.
The Surface Water and Ocean Topography (SWOT) satellite mission, launched in December 2022, vastly expands observations of river water surface elevation (WSE), width, and slope (Biancamaria et al., 2016). SWOT provides river vector products in shapefile format for each overpass. To enable multitemporal analysis, reaches and nodes must be defined a priori so that observations can be consistently assigned across passes. SWORD combines multiple global river and satellite datasets (GRWL, MERIT Hydro, HydroBASINS, GRanD/GROD) to define river nodes (~200 m spacing) and reaches (~10 km) with attached hydrologic variables and a consistent topology for global rivers 30 m wide and greater. SWORD is described by Altenau et al. (2021).
Before using SWORD, please read the SWORD Product Description Document. For questions, email sword.riverdb@gmail.com.
v17c preserves the topology and reach/node definitions of v17b and adds observation-based and routing variables:
- SWOT observation statistics — per-reach and per-node distributions (percentiles, range, MAD) of water surface elevation, width, and slope derived from actual SWOT passes.
- Mainstem routing — mainstem identification (
is_mainstem,main_path_id) and main upstream/downstream neighbor selection (rch_id_up_main,rch_id_dn_main). - Hydrological distances — Dijkstra shortest-path and mainstem distances to outlet (
dist_out_dijkstra,hydro_dist_out) and width-prioritized headwater/outlet endpoints (best_headwater,best_outlet). - Corrected flow accumulation — denoised
faccat 95,880 reaches (38.6%) where inherited values were physically inconsistent.
All original v17b variables are retained. See the release notes for the full list.
Documentation:
- v17c Release Notes (PDF) — summary of changes and new variables
- v17c Variable Reference (PDF) — detailed variable descriptions and encodings
Version 17 (October 2024)
- Topological updates for consistency
- Distance-from-outlet recalculation from shortest paths between outlets and headwaters
- New variables:
path_freq,path_order,path_segs,main_side,stream_order,end_reach,network - Improved reach geometry; additional channels for connectivity; new reach and node IDs; corrected node lengths
Version 17b (March 2025)
- Type change for 1,662 reaches and associated nodes globally, updating impacted Reach and Node IDs
- Corrections to reach/node lengths and distance-from-outlet for select reaches (<2% globally)
Version 17c (2026)
- SWOT observation statistics for WSE, width, and slope
- Mainstem routing and main neighbor selection (
is_mainstem,main_path_id,rch_id_up_main,rch_id_dn_main) - Dijkstra and mainstem hydrological distances (
dist_out_dijkstra,hydro_dist_out) - Width-prioritized endpoints (
best_headwater,best_outlet) - Corrected flow accumulation (
facc)
- SWORD Explorer — explore and download the current version interactively
- Zenodo — versioned archive with a DOI for citation
Available formats: NetCDF, GeoPackage, ESRI Shapefile, GeoParquet, and DuckDB, per continent and as global merged files.
Please cite the Zenodo record:
James H. Gearon, Elizabeth H. Altenau, Tamlin M. Pavelsky, Michael T. Durand, Niek Collot d'Escury, Xiao Yang, Pierre-Olivier Malaterre, Renato P. d. M. Frasson, & Liam Bendezu. (2026). SWOT River Database (SWORD) (Version v17c) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.21415370
Alternatively, or in addition, cite the development publication:
Altenau, E. H., Pavelsky, T. M., Durand, M. T., Yang, X., Frasson, R. P. D. M., & Bendezu, L. (2021). The Surface Water and Ocean Topography (SWOT) Mission River Database (SWORD): A global river network for satellite data products. Water Resources Research, 57(7), e2021WR030054. https://doi.org/10.1029/2021WR030054
Concept DOI (always resolves to the latest version): https://doi.org/10.5281/zenodo.3898569
This repository holds the code used to develop, validate, and maintain SWORD. See docs/ for technical documentation.
 SWORD reach numbers per continent. Colors display distance from outlet calculated from shortest paths between outlets and headwaters.