FIMbench: An Extensive Benchmark Flood Inundation Mapping Database

Overview FIMbench is an extensive, multi-tier, multi-source benchmark Flood Inundation Mapping (FIM) database and the toolkit that powers it. It brings benchmark flood maps from many sources into one standardized, programmatically queryable database and connects seamlessly to evaluation frameworks such as FIMeval so model predictions can be benchmarked against as many reliable reference maps as possible. The dataset contains 204 flood maps across CONUS. It is developed under the Surface Dynamics Modeling Lab (SDML) at the University of Alabama as part of a project funded by the Cooperative Institute for Research to Operations in Hydrology (CIROH). Data Description FIM TiersBenchmark FIM rasters are provided in four tiers plus a separate High Water Mark class (NoData = -9999 for all). Tier 1 (20–50 cm): Derived from NOAA Emergency Response Imagery, classified into flooded (1) and non-flooded (0) pixels. Tier 2 (3–5 m): Derived from PlanetScope imagery with a hydrologically guided gap-filling algorithm; classes are non-flooded (0), observed flooded (1), and gap-filled flooded pixels (2). Tier 3 (10 m): Derived from Copernicus Sentinel-1 SAR imagery with the same gap-filling approach with classes non-flooded (0), observed flood (1), and gap-filled flood (2). FEMA BLE (10m): Base Level Engineering HEC-RAS flood maps for 100- and 500-year events at the HUC-8 level generated by FEMA; classes are flooded (1) and non-flooded (0). HWM (10 m): Built from surveyed USGS high water marks and a 10 m DEM; classes are flooded (1) and non-flooded (0). FIMbench organizes the data under top-level prefixes, corresponding to the five classes (Tier 1, Tier 2, Tier 3, FEMA BLE, and HWM). Each flood event is stored under its own event-level prefix, which contains the flood map in GeoTIFF (.tif) format, the flood extent boundary in GeoPackage (.gpkg) format, and an associated metadata file in JSON (.json) format Data access The FIMbench benchmark dataset is hosted on AWS. Link to AWS S3 bucket. FIMbench in the web-GUI: https://fimbench.tethys.ciroh.org Source code: This Zenodo record archives the FIMbench codebase, maintained on GitHub. It provides an automated platform for: Standardized file naming conventions Metadata generation Web tile creation for visualization