Challenges and Lessons Learned in 2D Flood and Dual Drainage Modeling Using PCSWMM

Early-career engineers are often tasked with applying advanced hydraulic and hydrologic modeling tools to complex urban water management challenges soon after entering professional practice. This presentation is delivered from the perspective of a new engineer transitioning from university to professional practice and focuses on the application of PCSWMM for two urban infrastructure projects in Atlanta.

The first project, the Hillside and Broadland Stormwater Improvements Project near Chastain Park, addressed recurring flooding of residential properties adjacent to an urban creek. The objective was to evaluate potential drainage improvements. As a new engineer, I learned PCSWMM through self-directed use of CHI documentation and training resources. A two-dimensional hydraulic model was developed using FEMA flood data and existing survey information to evaluate flood extents and frequencies under multiple storm events. The model incorporated hydraulic obstructions and was coupled with a one-dimensional conveyance system to represent culverts and channelized flow paths. Through this process, I gained key insight into when 1D and 2D modeling approaches are appropriate, how to develop and refine 2D meshes, and how data limitations constrained model performance.

The second project, the Monroe Drive Complete Streets Improvement Project, required development of a dual drainage model for a major urban roadway corridor. With limited in-house experience, I constructed a one-dimensional storm sewer model and converted it into a dual drainage system to simulate interactions between surface runoff and subsurface conveyance. Model development involved extensive troubleshooting and validation, including independent calculations, review of FHWA HEC-22 guidance, and verification of PCSWMM results. Through this work, I developed advanced proficiency in PCSWMM, which was later applied to assist other project teams.

This presentation highlights practical PCSWMM workflows, common challenges, and verification strategies encountered from a new engineer’s perspective, providing insight relevant to both early-career practitioners and experienced modelers involved in urban stormwater management.

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