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Continental U.S. · NHDPlus HR

Watershed modeling for every river in the continental U.S.

Build with SWAT+. Couple groundwater with MODFLOW 6. Calibrate in the AWS cloud — streamflow, nutrients, PFAS, and groundwater. Explore results in the browser.

Start with your watershedView featured models

Built with:

  • USGS NWIS
  • NHDPlus HR
  • WBD
  • gSSURGO
  • NLCD/CDL
  • PRISM
  • NSRDB
  • SWAT+
  • QSWAT+
  • SWAT+ Editor
  • MODFLOW 6
  • Flopy
  • GDAL
  • SGX3D
  • AWS

SWATGenX in three minutes

Frames from platform runs — SWAT+ assembly, MODFLOW 6 coupling, USGS calibration, site-scale PFAS.

Flagship film · 3 min 20 s · real model frames · privacy-enhanced YouTube on play.

More films on the SWATGenX channel →

Capability tour

Eight pillars of SWATGenX

All eight ship in one watershed workflow and one portable SWAT+ project.

01 · National groundwater inventory

28.8 million well records — collected and harmonized.

State agency well logs, interval-by-interval — searchable, mappable, and ready for MODFLOW 6 setup.

Explore groundwater data →
National groundwater modeling-readiness map
National modeling-readiness surface derived from depth-resolved groundwater well records
CONUS modeling-readiness from the well inventory.
Database specs
28,800,000
lithology depth intervals
7,900,000
mapped well records
46
CONUS states
856,000
model-ready (screen + yield)

02 · National PFAS data moat

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 →
Live inventory counts
94,100+
monitoring stations
1,212,680+
PFAS observations
30,972+
depth-resolved soil records
196,710+
screened potential sources
CONUS PFAS monitoring and soil coverage map
CONUS map of measured PFAS inventory coverage, with agency source counts by state
Monitoring stations, depth-resolved soil profiles, and screened facilities — counts from live APIs.

03 · HUC8 → HUC12 → HUC14

Model the reach you study, not the whole basin above it.

Cut at a gauge, a HUC12 outlet, or a single HUC14 catchment — and let the model above it supply the boundary.

See nested modeling →
Peace River, FL — the same basin cut at successive gauges: 3,832 km² and 39 HUC12 units at Arcadia (USGS 02296750), 1,448 km² and 13 of those 39 at Bartow (USGS 02294650).
Platform scale
25,335
USGS streamgages indexed for model building
87,387
HUC12 watersheds in the Explorer catalog
10 m · 30 m · 250 m
3DEP DEM · NLCD/CDL land cover · gSSURGO soils
4 km · 2 km
PRISM climate · NSRDB solar

04 · SWAT+ / MODFLOW 6 coupling

Fully coupled SWAT+/MODFLOW 6 via BMI/XMI.

One model across land, vadose zone, and groundwater — no linking-file pipeline. Inspect long runs in 3D.

See coupled modeling →
Tampa Bay tributaries — coupled SWAT+/MODFLOW 6, full-orbit from SGX3D.

Coupling specs

  • InterfaceMODFLOW 6 BMI/XMI — no linking-file pipeline
  • PathLand ↔ UZF/UZT vadose ↔ groundwater ↔ streams
  • CodesSWAT+ land/channel · MODFLOW 6 GWF + GWT
  • ConstituentsNative PFAS F&T in the coupled run

Live SGX3D on PFAS fate & transport · open viewer

05 · PFAS fate and transport

PFAS fate and transport in coupled SWAT+/MODFLOW 6.

Freundlich sorption, UZF/UZT vadose delay, and GWT aquifer transport — soil to streams. Wurtsmith AFB is the example.

See the PFAS science →
Wurtsmith PFOS · ~250 m · 3 layers · 1971–2024 · SGX3D capture.

Example site — Wurtsmith AFB

  • EngineCoupled SWAT+/MODFLOW 6 — native PFAS F&T
  • SorptionFreundlich soil sorption (Kf / n)
  • Vadose → aquiferUZF/UZT retardation · MODFLOW 6 GWT
  • ExampleWurtsmith AFB — PFOS 1971–2024 · ~250 m · 3 layers

Interactive run on PFAS fate & transport.

06 · Public MCP server

Ten MCP tools for Claude and Cursor.

Search models, query groundwater and PFAS inventories, preview builds — and with a key, order and download SWAT+ packages.

See how to connect →
11 MCP tools

What the assistant can call

Claude · Cursor · other assistants
  • search_swat_modelsBrowse the example-model catalog (state, size, calibration status)Open with account
  • get_model_calibrationCalibration and held-out validation NSE / PBIAS for one modelOpen with account
  • query_groundwaterNearest wells and lithology from the 28.8M-interval national inventoryOpen with account
  • query_pfasNational PFAS monitoring inventory by state or analyteOpen with account
  • request_modelPreview what SWATGenX would build for a gauge or HUC12 outletOpen with account
  • get_engine_infoSWAT+ engine fork, compile guide (/compile-swat-plus), and toolchain pointersOpen with account
  • get_access_infoThe access ladder and your current tierOpen with account
  • order_modelOrder a real SWAT+ build (fair-use allocations apply)API key
  • get_order_statusTrack a build order to completionAPI key
  • list_my_modelsList your build ordersAPI key
  • download_modelMint a 24-hour pull link; your agent saves the ZIP locallyAPI key

Connect once. Catalog, inventories, previews — API key for order and download.

07 · Open parallel SWAT+ engine

Byte-identical parallel SWAT+ for HRUs and streams.

OpenMP wavefront on HRUs and channel routing. Certified byte-identical — 18 of 18 checks, 935,130 values each — ~7× on Peace River.

See engine benchmarks →
Thread scaling — one simulated yearAWS c8a · 32 cores
0×2×4×6×ideal124816245.33×threads
One-year run: 143 s → 27 s. Self-relative speedup of the parallel binary; still climbing at 24 threads.

08 · Automated cloud calibration

Fully optimized MMPSO calibration on dedicated AWS.

Calibrate SWAT+ against USGS streamflow on per-job EC2 instances — parallel MMPSO, live dashboard convergence, AWS billed at cost.

See cloud calibration →
SWATGenX calibration wizard Review and launch — model, gauges, windows, parameters, and compute
Calibration wizard — review gauges, windows, and compute before launch.

Calibration specs

  • AlgorithmParallel role-aware MMPSO (PSO swarm)
  • TargetUSGS streamflow — calibration + held-out validation
  • ComputeDedicated per-job AWS EC2 — spot / on-demand auto-selected
  • CostAWS billed at cost — estimate shown before launch

Watershed science, end to end

One platform — from national inventories through coupled models, cloud calibration, and a parallel engine.

Explore free. Connect Claude or Cursor over MCP. Create an account when you order a SWAT+ package.

Open Watershed ExplorerSign in

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.

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