Open standards · Open engines · AI-ready

Digital public water infrastructure, built in the open and ready for AI

Open-Source SWMM 6.0 GUI showing a coupled 1D and 2D flood simulation over aerial imagery of the Bellinge catchment, with velocity vectors, a conduit profile view, and a live attribute table
Enabling architectures that spur innovation in water modeling

The water systems that protect our communities are increasingly managed through models of rainfall, runoff, pipes, streams, and aquifers. HydroCouple develops the enabling architectures of the digital water transformation: open interface definitions, data standards, and computational engines that let these models connect into a single, composable representation of the entire water cycle, from watersheds and aquifers to sewers, streams, and receiving waters. Open-Source SWMM 6.0 (SWMM2D), a HydroCouple initiative, is the flagship engine. Because the whole stack speaks standard interfaces, anyone can build on it: new components, new science, new tools, and artificial intelligence in modeling, operations, and control.

Explore the Ecosystem Read the Standards AI + Water Modeling
Agent-driven modeling via MCP Real-time control Hybrid physics-AI modeling
The challenge

Water doesn't respect model boundaries

A storm moves through a city as one connected event: rain becomes runoff, runoff enters sewers, sewers surcharge into streets, streams exchange with groundwater. Yet the models that simulate each of these processes have historically been silos: separate codes, separate file formats, separate assumptions, glued together with one-off scripts that break and can't be reproduced. The digital water transformation demands a public, standards-based integration layer that any model can plug into.

Composable models

Process models compiled as components with standard interfaces, organized into coupled compositions that represent whole systems.

Standard data in, standard data out

Interface definitions built around standard geospatial data (time series, meshes, networks, rasters) so exchanged quantities carry their geometry, units, and metadata.

Built for modern computing

Interfaces designed for HPC and cloud execution: component cloning, parallel runs, and customizable data-exchange workflows for calibration and uncertainty analysis.

The architecture

Interface definitions are the glue

Every component in the ecosystem (hydrologic, hydraulic, water quality, groundwater) implements the same HydroCouple interface definitions. That common contract is what turns a collection of independent codes into an integrated digital representation of public water infrastructure. Open-Source SWMM sits at the center; the interfaces make the coupling possible.

Sensors & SCADA rain gages · level · flow Climate Forcing reanalysis · forecasts · scenarios GIS & Asset Data networks · terrain · land use Observed Records calibration · validation HydroCouple Interface Definitions IComponent · IExchangeItem · IArgument · IGeometry · ITime · IUnit FLAGSHIP ENGINE Open-Source SWMM 6.0 (SWMM2D) hydrology · hydraulics · water quality 1D/2D · GPU-ready · reentrant engine Groundwater head-driven exchange 2D Overland Flow street-scale flooding Stream Temperature solute & heat transport Hydrologic Models finite volume · snowmelt Flood-risk planning consent decrees · resilience Real-time operations forecasting · smart control Water-quality compliance TMDLs · CSO/SSO reporting
One integration layer, many models: data sources flow through the HydroCouple interface definitions to a composable set of model components, with Open-Source SWMM 6.0 (SWMM2D) at the center, supporting planning, operations, and compliance.
The centerpiece

Open-Source SWMM 6.0 (SWMM2D): a public model, reimagined

For five decades, EPA's Storm Water Management Model has been the public backbone of urban stormwater engineering. Open-Source SWMM 6.0 (SWMM2D), a HydroCouple initiative, carries that legacy forward as a community-driven, next-generation engine: a modern C++20 rewrite with a reentrant core, data-oriented design, GPU-capable 2D solvers, Python bindings, and an agent-ready tooling layer, released in the open and validated against published benchmarks.

Flagship

Engine

Next-generation computational core: hydrology, hydraulics, and water quality with a reentrant API, structure-of-arrays performance, plugin I/O, and 1D/2D coupling.

openswmm.engine →

Available

Desktop GUI

A modern interface for building, running, and interrogating models, bringing the next-generation engine to practicing engineers.

openswmm.gui →

Available

Agent & MCP Tooling

A Model Context Protocol server exposing the engine to AI agents and LLM-driven workflows to build, edit, run, and analyze models programmatically.

openswmm.mcp →

50+years of public SWMM science
C++20modern, reentrant engine core
1D + 2Dcoupled hydraulics with GPU backends
1,396models in the open benchmark corpus
OpenApache-2.0 engine · open standards
Get involved

Help build the water infrastructure commons

HydroCouple and Open-Source SWMM 6.0 (SWMM2D) are developed in the open. Use the models, report issues, contribute components, or bring your utility's use case to the table.

Contribute on GitHub See What's Planned