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Continental U.S. · NHDPlus HR

Watershed modelingfor every riverin 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 · Measured soil PFAS inventory

30,972 measured soil PFAS records from 141 sources.

Public agency measurements, source and method retained — for screening and site research.

Explore soil PFAS data →
Database specs
30,972
analytical records
141
agency source datasets
41
states
72
PFAS analytes
CONUS soil PFAS coverage map
CONUS map of measured soil PFAS inventory coverage, with agency source counts by state
Measured soil PFAS by state — as reported, no interpolated surface.

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.