FloPy
Open SourceVerified
The Python interface to MODFLOW — build, run and post-process groundwater models entirely in code.
PEST
ActiveModel-independent parameter estimation and uncertainty analysis — the calibration standard for groundwater models.
by Watermark Numerical Computing
- Pricing
- Free
- License
- Freeware (open specifications)
- Commercial use
- Permitted
- Ecosystem
- Standalone, MODFLOW, Any file-driven model
- Platform
- Windows, Linux
About PEST
PEST, by John Doherty of Watermark Numerical Computing, is the tool that made rigorous calibration routine in groundwater practice. It treats any model as a black box — communicating through the model's own input and output files — and performs gradient-based parameter estimation, regularised inversion with pilot points, and predictive uncertainty analysis.
Its concepts (Tikhonov regularisation, highly parameterised inversion) define how the industry thinks about calibration, and its file protocols are supported by every serious groundwater GUI. The newer PEST++ suite reimplements and extends the ideas with iterative-ensemble methods; both remain free.
Where it fits in the workflow
TerrainCatchmentRainfallRunoffRoutingHydraulicsMappingReporting
Appears in collections
- The Modern MODFLOW Stack
Groundwater modelling entirely on free software — MODFLOW 6, FloPy, PEST++ and friends.
Alternatives to PEST
Ranked by the topics, categories and workflow stages they share with PEST.
Groundwater Vistas
Commercial
Veteran commercial MODFLOW GUI with deep PEST integration — a consultant favourite for calibration-heavy work.
MODFLOW 6
Gov-PublicVerified
The USGS groundwater model — the world standard for aquifer simulation, rebuilt as a modular multi-model framework.
MT3D-USGS
Gov-Public
Multi-species solute transport for MODFLOW — advection, dispersion, sorption and reactions in aquifers.
ModelMuse
Gov-Public
The USGS's free graphical interface for MODFLOW — grid-independent model design without a commercial GUI.
Visual MODFLOW Flex
Commercial
3D groundwater flow and transport modeling environment for MODFLOW, SEAWAT, and PEST calibration workflows.