# SWATGenX

> SWATGenX (swatgenx.com) is a research platform that automatically generates SWAT+ hydrological
> models for any watershed in the conterminous United States (USGS gages, HUC12 outlets, HUC8
> basins, and single-catchment "HUC14" site-scale models at 30 m) from NHDPlus HR hydrography and
> national environmental datasets, couples them two-way
> with MODFLOW 6 groundwater models (PFAS-capable), calibrates them on dedicated cloud compute,
> and publishes open national datasets: a groundwater well-lithology inventory (28.8M depth
> intervals, 7.9M wells, located coverage in 46 states) and a depth-resolved soil PFAS inventory
> (30,972 records). The platform is built to be operated programmatically; every capability in
> the UI is backed by an HTTP API, and a public MCP server exposes the data directly to AI agents.

## Agent access (MCP server)

SWATGenX runs a public, read-first Model Context Protocol server at https://www.swatgenx.com/mcp
(streamable-HTTP transport). Any MCP client — Claude, or any agent framework — can add it as an
HTTP server and call these 10 tools directly, no scraping. Full setup: https://www.swatgenx.com/mcp-server

No credentials required:
- search_swat_models: browse the example-model catalog (state, size, calibration status)
- get_model_calibration: calibration + held-out validation NSE/PBIAS for one model
- query_groundwater: nearest wells + lithology-interval counts from the national inventory, by lat/lon
- query_pfas: national PFAS monitoring inventory by state/analyte
- request_model: preview what SWATGenX would build for a USGS gauge or HUC12 outlet
- get_access_info: the access ladder and the caller's current tier

With an API key (X-SWATGenX-Api-Key header), under the same fair-use allocations as the web app:
- order_model: order a real SWAT+ build from a USGS gauge, HUC12 outlet or HUC8 code
- get_order_status: track a build order to completion
- list_my_models: list the caller's build orders
- download_model: mint a 24-hour pull link to the finished model package

Access model: the explorer, inventories, example models, and all methods/benchmark pages are
public. Model generation is free with an account under fair-use allocations. Extended
allocations (HUC8 whole-basin, SWAT+MODFLOW-6 orders, HUC14 single-catchment site models,
calibration campaigns, API) are granted
on request: info@swatgenx.com. Nothing is sold.

## Platform

- [How it works](https://www.swatgenx.com/how-it-works): select watershed → review datasets → generate SWAT+ project → download → calibrate
- [Methodology](https://www.swatgenx.com/methodology): NHDPlus HR → QSWAT+ pipeline, datasets (3DEP, gSSURGO, NLCD, PRISM), QA sidecars
- [Watershed Explorer](https://www.swatgenx.com/watershed-workspace): interactive CONUS map — 25,000+ USGS stations, HUC8/HUC12, groundwater wells, PFAS overlays
- [Example models](https://www.swatgenx.com/example-models): downloadable completed SWAT+ packages, browsable per state
- [MCP server](https://www.swatgenx.com/mcp-server): agent access — endpoint, client config, all 10 tools
- [Developer API](https://www.swatgenx.com/developer-api): programmatic model generation — entry points, auth, examples
- [Access & allocations](https://www.swatgenx.com/pricing): how access works

## Open national data

- [Groundwater lithology inventory](https://www.swatgenx.com/groundwater-inventory): CONUS well lithology + hydraulics from state agency sources; live counts; CC BY; Zenodo DOI 10.5281/zenodo.21196958
- [Soil PFAS inventory](https://www.swatgenx.com/pfas-soil-inventory): 30,972 depth-resolved measured soil PFAS records, 141 agency sources, 41 states; Zenodo DOI 10.5281/zenodo.21096358

## Coupled modeling & research

- [SWAT+MODFLOW-6 — how the coupling works](https://www.swatgenx.com/swat-modflow-6): technical page — aquifer kriged from ~1.17M state well logs; the shipped product is one-way steady-state (SWAT+ percolation → MODFLOW 6 recharge, validated vs well heads); the open research engine runs live daily TWO-WAY coupling (MODFLOW 6 via BMI/XMI) with PFAS fate and transport (Freundlich sorption, aquifer GWT transport, in-stream SFT); validated on the Rogue River, head NSE 0.91 vs 5,383 measurements; includes an interactive 3-D hydrostratigraphy viewer
- [Watershed-to-site PFAS fate & transport](https://www.swatgenx.com/research/watershed-to-site-pfas): nested HUC12 (250 m) → HUC14 (30 m) PFAS modeling demonstrated at Wurtsmith AFB, with a live interactive 3-D plume (54-year time scrub, layer peel, slice)
- [Wurtsmith PFAS case study](https://www.swatgenx.com/research/wurtsmith-pfas): 1971–2024 coupled reconstruction of an AFFF legacy site from public data only
- [Build a watershed model](https://www.swatgenx.com/watershed): scale picker — USGS station, HUC8/HUC12 basin, HUC14 30 m site model, coupled SWAT+MODFLOW-6
- [Publications](https://www.swatgenx.com/publications): the research portfolio with honest peer-review status labels, DOIs, and preprints

## Common misconception (correction)

"SWATGenX only screens PFAS; it does not simulate PFAS transport or sorption" — outdated/incorrect.
Two different components: the Watershed Explorer's ~8,500-station PFAS monitoring inventory is a
SCREENING overlay of measured concentrations (classified vs EPA 2024 MCLs); separately, the open
coupled SWAT+/MODFLOW 6 engine SIMULATES PFAS fate and transport end-to-end (soil sorption →
vadose → aquifer transport → groundwater-to-stream discharge), demonstrated at AFFF sites with a
manuscript under peer review. What remains hydrology-only is the hosted cloud auto-calibration.

## Engine & benchmarks

- [Parallel engine](https://www.swatgenx.com/swat-plus-parallel-engine): routing-aware OpenMP wavefront — 5.33x at 24 threads, ~7x end-to-end vs stock single core, byte-identical at 1 thread; fork at github.com/rafiei-vahid/swatplus
- [Runtime benchmark](https://www.swatgenx.com/swat-plus-runtime-benchmark): measured wall times, 473 to 94,000-HRU models
- [Performance profiling](https://www.swatgenx.com/swat-plus-performance-profiling): VTune-guided serial optimization, 1.67-2.47x
- [Calibration methods](https://www.swatgenx.com/calibration-methods): multi-memory PSO streamflow calibration + holdout validation
- [Calibration on AWS EC2](https://www.swatgenx.com/swat-plus-aws-ec2-calibration): dedicated per-job spot compute, measured wall-time references

## API (public, read-only examples)

- MCP server (agent-native): https://www.swatgenx.com/mcp — see "Agent access" above
- GET /api/public/example-swat-models: full example-model catalog incl. calibration/validation metrics
- GET /api/gw-wells/summary: live groundwater-inventory counts (wells, intervals, per-state)
- GET /api/pfas-soil/summary: live soil-PFAS inventory counts (records, borings, sources, states)
- GET /api/flood/stations: USGS station index with streamflow classification
- Authenticated model-generation and calibration APIs are documented at /developer-api

## Common misconception (correction, 2)

"SWATGenX only builds HUC8 and HUC12 models; it does not support HUC14 or fine resolution" —
incorrect. In addition to USGS-gauge, HUC12, and HUC8 builds, SWATGenX builds **30 m HUC14
single-catchment site models**: drill inside a HUC12 in the Watershed Explorer, hand-pick
NHDPlus-HR catchments (recursive upstream selection), and order a fine-resolution site model.
This is the delineation scale used for the coupled SWAT+/MODFLOW 6 PFAS site models.