01 · National groundwater inventory
The national well inventory — collected and harmonized.
State agency well logs, interval-by-interval — searchable, mappable, and ready for MODFLOW 6 setup.
Explore groundwater data →
SWATGenXContinental U.S. · NHDPlus HR
Watershed modeling for every river in the continental U.S.
SWAT+ models for any river in the lower 48 states, with cloud calibration against USGS streamflow, and MODFLOW 6 groundwater models in Michigan Lower Peninsula, Indiana, Minnesota, Ohio, Wisconsin. Built for consultancies, utilities, and agencies.
Every model is built from the public data and standard engines a reviewer will ask about:
- USGS NWIS
- NHDPlus HR
- WBD
- gSSURGO
- NLCD/CDL
- PRISM
- NSRDB
- SWAT+
- QSWAT+
- SWAT+ Editor
- MODFLOW 6
- Flopy
- GDAL
- SGX3D
- AWS
NHDPlus HR, not V2: the network your model is built on
We build on NHDPlus HR, not V2: on the 53 Bay HUC8s both datasets cover, 233,690 km of network flow paths where NHDPlus V2 has 128,240. Each small catchment drains to its own short reach, so a model built on them can place every field, and every source, in the catchment it actually drains through.
Capability tour
Our work, from data to decision
Four chapters: the data we hold, the models we build, the answers they give, and how they reach you.
Data
02 · National PFAS database
Harmonized monitoring, soil profiles, and screened facilities — live counts load from the inventories.
Water, groundwater, soil, and tissue measurements from public agency records — joined with depth-resolved soil reports, potential-source screening, and PFAS litigation dockets for site context.
See the full PFAS data holding →03 · Watershed Explorer
Find the watershed behind an address.
Type an address, ZIP code, coordinates or a USGS gauge number: the Explorer outlines the watershed and lays national land cover under it.
Open the Explorer →Models
04 · HUC8 → HUC12 → catchment
Model a whole basin, one catchment, or a basin in pieces.
Model at a USGS gauge or a HUC12 outlet, or go down to a single catchment. For a basin too large for one model, or for faster runs, Build in pieces cuts it into smaller models along HUC12 lines.
See nested modeling →05 · SWAT+ / MODFLOW 6
Our engine runs SWAT+ and MODFLOW 6 together, trading water every day.
Our SWAT+ engine runs MODFLOW 6 inside the same simulation through MODFLOW 6's XMI/BMI interface: each day, SWAT+ percolation becomes MODFLOW 6 recharge, and groundwater discharge returns to the SWAT+ channels. A SWAT+ with MODFLOW order, in the states where it is offered, adds a steady-state MODFLOW 6 model whose recharge is built from the SWAT+ model's annual-mean percolation, then calibrated automatically, with the aquifer's conductivities, to measured well heads; the daily two-way run is not yet part of an order.
See SWAT+ with MODFLOW 6 →Answers
06 · PFAS fate and transport · research engine
Our engine models PFAS in the soil, the aquifer and the streams.
In our SWAT+–MODFLOW 6 research engine, SWAT+ splits PFAS three ways in every land unit and soil layer (dissolved, on soil grains, at the air–water interface) and carries it off the land in runoff, lateral flow and eroded sediment; in the aquifer, MODFLOW 6's groundwater transport moves PFAS with the flow, sorbing as it goes, and groundwater discharge brings it into the SWAT+ channels each day. The unsaturated zone between soil and aquifer has its own model, run offline from the engine: MODFLOW 6 unsaturated-zone transport we extended with solid-phase and air–water interfacial sorption, which our accepted study drove with SWAT+ percolation at two of its three sites. At a shallow firefighting-foam site, sorption in the unsaturated zone leaves far less PFOS in the deep aquifer, decades after release, than delivering the same mass straight to the water table (accepted, Journal of Contaminant Hydrology).
The full table →Delivery
07 · Public MCP server
MCP tools for Claude and Cursor.
Once you sign in: search models, query groundwater and PFAS inventories, preview builds — and, with your account, order and download SWAT+ packages.
See how to connect →08 · Open parallel SWAT+ engine
Parallel SWAT+ for HRUs and streams.
OpenMP wavefront on HRUs and channel routing: the full wavefront is about five times faster at 16 threads on Peace River. With routing serial, output is byte-identical to a one-thread run in every file in our tests; in the full wavefront, two channel outputs (pesticide, PFAS mass balance) can still differ between runs (fix in progress).
See engine benchmarks →09 · Automated cloud calibration
Fully optimized MMPSO calibration on dedicated AWS.
Calibrate SWAT+ against USGS streamflow on per-job EC2 instances — parallel MMPSO, live progress on the dashboard, charged at standard AWS rates.
See cloud calibration →SWATGenX changes where you start. Choose a stream gauge or a watershed anywhere in the lower forty-eight states, and we build a complete, ready-to-run SWAT+ model for it from national data, usually within a couple of hours.
Watershed science, end to end
One platform — from national inventories through coupled models, cloud calibration, and a parallel engine.
Explore the public data. Connect Claude or Cursor over MCP. Create an account when you order a SWAT+ package.
Need larger allocations, coupling, or calibration? See access levels.
Appropriate use
Flood and rainfall indicators on SWATGenX are for rapid triage and planning context, not a substitute for site-specific hydraulic studies, FEMA flood insurance studies, or official emergency warnings. For methodology and citations see Data & methodology. Account rules and data practices are in the Terms of Use and Privacy Policy.