What This Tutorial Covers

This tutorial serves as a hands-on guide for professionals using GeoSWMM, with a focus on the practical application of dual drainage system modeling in urban stormwater networks. It is intended for users who already have a working knowledge of hydrology, hydraulics, stormwater management modeling, model input data in ArcGIS Pro and the use of EPA SWMM elements and flow routing methods for representing drainage systems.

The tutorial walks users through the process of modeling a dual drainage system in which stormwater is conveyed through both minor and major drainage pathways. In the study area introduced in Tutorial 02, the primary conveyance system consists of natural channels and underground circular pipes. During small and frequent storm events, runoff is carried through these conduits and routed to the outlet. During larger storm events, however, the system may surcharge, causing stormwater to flow over streets. To represent this behavior, roadside gutters are added to the network to function as surface conveyance channels during heavy rainfall. These skills are especially relevant for engineers and planners analyzing urban drainage performance under storm conditions that exceed underground system capacity.

Users will learn how to represent surcharge conditions, simulate surface overflow routing, and evaluate how a dual drainage system performs under heavy storm events. This tutorial complements the GeoSWMM User’s Manual by offering a structured, example-driven walkthrough of real-world modeling scenarios.

The following section begins a step-by-step demonstration of the worked example project, guiding users through each stage of setting up and analyzing a dual drainage system in GeoSWMM.