What This Tutorial Covers

This tutorial serves as a hands-on guide for professionals using GeoSWMM, with a focus on the practical application of urban stormwater quality modeling through pollutant buildup and washoff simulation. 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, along with a basic understanding of how land use conditions influence runoff quality in urban catchments.

The tutorial walks users through the simulation of pollutant buildup during dry periods and pollutant washoff during storm events within an urban catchment. It emphasizes key tasks such as defining pollutant accumulation patterns under different land uses, selecting suitable washoff approaches, and applying empirical the equations of Exponential functions (EXP) and Event Mean Concentration (EMC). These skills are especially relevant for engineers and planners evaluating the environmental impact of wet-weather flows and assessing nonpoint source pollutant loading from developed areas.

Users will learn how to represent pollutant dynamics in GeoSWMM, calibrate buildup behavior over dry periods, and simulate pollutant transport in stormwater runoff. The tutorial also helps users understand how empirical formulations can be used to model runoff quality where pollutant transport mechanisms are complex and calibration data may be limited. Using the same study area presented in Tutorial 05, this worked example demonstrates how pollutant accumulation and washoff processes can be effectively analyzed in a practical urban setting. 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 simulating urban runoff water quality in GeoSWMM.