Kansas State University

Lake-TopoCat provides a global-scale dataset that links lakes with their drainage topology, delineates catchments, defines inter-lake pathways, and quantifies topological attributes (upstream/downstream relationships, drainage distances, outlet multiplicity, etc.). The input is based on HydroLAKES v1.0 and MERIT Hydro (3 arcsec), with algorithms to detect possible lake bifurcation, unit catchment delineation, reach segmentation, and network attribution. The database includes: Lake boundary polygons (same as HydroLAKES) enriched with drainage attributes Lake outlet points Unit catchment polygons corresponding to each lake outlet Inter-lake reach lines connecting outlets Lake-network basins (basin polygons delineating the full drainage domain of each lake network) It covers ~1.43 million lakes (≥10 ha) and ~1.46 million outlets globally, and ~3 million inter-lake reaches, spanning ~77.5 × 10⁶ km² of catchment coverage (≈ 57 % of global landmass, excluding Antarctica). The dataset is freely available via Zenodo (DOI: 10.5281/zenodo.7916729) and is licensed under CC BY 4.0.