Linking GoldSim and EPA SWMM

EPA SWMM is a widely used industry standard for urban drainage and stormwater modeling, yet its internal water quality engine can be limiting for practitioners who need to model complex contaminant behavior. In this session, I will demonstrate a new integration that couples SWMM’s hydraulic precision with GoldSim’s Monte Carlo engine and Contaminant Transport (CT) Module. 

This integration allows SWMM to handle the physical routing of water while GoldSim provides the mathematical framework for tracking pollutant mass balance, advection, and dispersion. This connection is made through a pre-built bridge that allows you to focus on the modeling rather than the programming. This tool enables a synchronized connection between the two engines without the need to write custom code or manage complex APIs manually.

By linking these two platforms, users can move to a mass-based modeling approach that tracks the cumulative accumulation of solids (TSS) within Low Impact Development (LID) features. We will walk through a "Treatment Train" case study where GoldSim uses the flow and volume data from SWMM to calculate the fate of pollutants like Zinc, accounting for how they partition and sequester within filter media over time. This workflow supports Monte Carlo simulations, enabling you to evaluate system performance across thousands of stochastic realizations to quantify probabilistic risks and maintenance requirements. 

Below is a video recording of the webinar presentation:

Download the files used for this presentation:

GS-SWMM Example models

GS-SWMM Source Code