SARAH-CONUS: Sub-weekly Area of Reservoirs from Analysis of Harmonized Landsat and Sentinel-2 data for Continental US

This dataset provides reservoir water-surface areas every 2–6 days for 1,904 reservoirs (>0.1 km²) across the conterminous United States from 1 January 2016 through 31 December 2023. Areas were extracted from NASA’s Harmonized Landsat–Sentinel-2 Surface Reflectance product (HLS v1.4; 30 m) with a Random-Forest water classifier, a cloud/ice-correction enhancement based on the Global Surface Water Occurrence layer, and LOWESS gap-filling. Validation against daily in-situ surveys for 240 reservoirs yields R² = 0.98 and median bias < 10 %. The product (nick-named SARAH-CONUS) closes the temporal gap between daily MODIS (coarse) and monthly Landsat (fine), enabling analyses of flood-mitigation releases, hydropower peaking, evaporation losses, and greenhouse-gas pulses at a management-relevant cadence.