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About SWATGenX

Watershed models from national data — built, checked, and looked after.

SWATGenX is a watershed modeling company. Our platform builds complete SWAT+ models from public national data (NHDPlus HR hydrography, gSSURGO soils, NLCD land cover, PRISM climate) for any USGS gage, HUC12 outlet or HUC8 basin in the conterminous US. When a project needs more than a model, we do the modeling work with you.

Founded by Vahid Rafiei · operated by SWATGENX LLC, Michigan

Every USGS streamflow station in the conterminous US — from the SWATGenX platform film, rendered from real model data.

What we do

Model building.

One automated pipeline builds every model on NHDPlus HR, with the same rules everywhere, so a model for one watershed is built the same way as a model for any other. You get a standard SWAT+ project you can open, inspect and run yourself.

Surface water and groundwater.

A SWAT+MODFLOW order builds a steady-state MODFLOW 6 model designed to take its recharge from SWAT+ (today a uniform default of about 200 mm/yr, while that connection is finished). Daily two-way coupling, with recharge going down and baseflow coming back, is research work; transient coupled studies and PFAS fate and transport are project work.

Projects and services.

Model development, calibration, groundwater and PFAS studies, and reports, scoped and quoted per project. Plans run from Starter to Department.

How we work

  • Every model is checked against NHDPlus HR. After a model is built, its drainage areas are compared, channel by channel, with the hydrography it was built from, and a mismatch is fixed in the pipeline. How we check models
  • We look after what we deliver. If we find a problem in a model we built, we fix it in the pipeline, rebuild the model, and tell its owner what changed.
  • Nothing is hidden. Models are standard SWAT+ projects, and the methods are published. Publications
  • Calibration is its own step. A new model is built and checked, not calibrated. Calibration runs on cloud compute, and its results come with their statistics.
  • We contribute upstream. Fixes we made to the SWAT+ engine have been merged into the open-source SWAT+ project.

Why we built it

National datasets exist, and so does SWAT+. What was missing was a reliable way to join them at high resolution, the same way for every watershed, so modelers spend their time on analysis, TMDLs, BMP targeting and contaminant transport instead of assembling inputs.

Who we are

SWATGenX was founded by Vahid Rafiei, PhD, its CEO. He is a computational hydrologist who builds watershed, groundwater and PFAS fate-and-transport models, and the software that generates them from national data. SWATGenX is operated by SWATGENX LLC, a Michigan limited liability company. SWAT+ is jointly developed by USDA-ARS and Texas A&M AgriLife Research; SWATGenX is not affiliated with or endorsed by them.

ORCID · Google Scholar · GitHub · vahid@swatgenx.com

Limits

A generated model is a starting point to calibrate and validate for your purpose; we do not claim that every model is calibrated, validated or ready for regulatory use. See the Terms of Use and Privacy Policy.

Start with a watershed.

Page updated 2026-09-28.