Watershed Explorer
Map-based exploration of 25,000+ USGS stations, WBD catalog HUC12 watersheds, and every HUC8 in CONUS — streamflow context, PDF reports, and SWAT+ models in one place.
SWATGenX hosts the interactive watershed workspace: pick a USGS station, a catalog HUC12 watershed, or a whole HUC8 basin; view live streamflow context; generate PDF reports; and build SWAT+ models across the Continental United States — no GIS install.
Geographic and data coverage
- CONUS stream gauges — more than 25,000 USGS gauges. Each compares its latest daily flow with the same date in past years, and its latest reading with flood flows from a log-Pearson Type III fit to the gauge's annual peaks.
- Watershed units — WBD HUC8 basins and catalog HUC12 watersheds for basin-scale screening and model orders.
- National datasets — NHDPlus HR hydrography, PRISM climate, gSSURGO soils, NLCD land cover, and 3DEP elevation in generated SWAT+ packages.
- Groundwater — hosted SWAT+ with MODFLOW 6 builds in Michigan Lower Peninsula, Indiana, Minnesota, Ohio, Wisconsin (offered for screening; not a calibrated claim for every basin).
- PFAS map views — optional public soil-inventory and site-scale PFAS layers where inventories are posted.
Map layer glossary (crawlable summary)
- Streamflow status — the latest daily flow against the same date in past years (USGS daily statistics), and the latest reading against flood flows fitted to USGS annual peaks (log-Pearson Type III).
- Rainfall status — the last 24 hours of NOAA MRMS radar rain at each gauge against PRISM daily rain on rainy days at the same spot (75th to 99th percentiles).
- Floodplain zones — DEM-derived elevation/slope classes for screening (not FEMA regulatory maps).
- Population density — governmental boundaries clipped to the watershed with density buckets for exposure context.
- Cropland groups — CDL-based categories summarized for the basin.
Full methodology, steward links, and limitations: Data & methodology. In the live app, use the Methodology button for the same content in a modal.
The full map and analysis tools load in your browser. Use the links below to read about the platform or open other entry points.