HighWaterFIM: A Ground-Truth Dataset of Flood Inundation Extent for the United States

Overview The HighWaterFIM dataset is a collection of flood inundation maps generated from High-Water Marks (HWMs) observed during historical flood events across the United States. The dataset is produced using the HighWaterFIM workflow, which integrates statistical filtering, geostatistical interpolation, spatial autocorrelation analysis, and terrain-based flood mapping to derive inundation extents from point-based observations. The dataset contains 56 flood inundation maps representing 18 flood events occurring between 2010 and 2025, spanning diverse hydrologic and geographic conditions across the United States. Each flood map represents a high-confidence inundation extent derived from spatially filtered HWMs and is intended to support flood modeling, validation studies, and hydrologic research. Data Description The dataset is distributed as a compressed archive (Flood_Maps_from_HWMs.zip). Within the archive, flood maps are organized into subfolders corresponding to individual flood events:Flood_Maps_from_HWMs/- 2010_Aug_IA_Flood/- 2011_TropicalStormLee/Each flood event folder contains one or more flood inundation maps and associated spatial metadata. Flood Map Files Each flood inundation map is provided as a GeoTIFF raster (.tif) with a spatial resolution of 10 meters. File naming convention: YEAR_NAMEofFLOOD_FloodRegion.tifExample: 2010_Aug_IA_Flood_Region_0.tif Where:YEAR: Year of the flood eventNAMEofFLOOD: Identifier for the flood datasetFloodRegion: Unique numeric identifier for each generated flood map within a flood event The 'FloodRegion' ID is used solely to distinguish multiple inundation maps generated for a given flood event and does not carry physical or hierarchical significance. Bounding Box ShapefilesEach flood map is accompanied by a corresponding bounding box shapefile that defines the spatial extent of the flood raster. Data Characteristics Spatial resolution: 10 metersData type: Binary flood inundation maps (flooded vs. non-flooded)Coverage: Continental United StatesTemporal range: 2010–2025Number of flood events: 18Total flood maps: 56