Urban drainage modeling, software development, and practical knowledge-sharing since 1978
I’m Robert “Bob” Dickinson, a water-resources modeling specialist, software developer, and technical educator. I’ve worked with the U.S. EPA’s Storm Water Management Model—SWMM—since 1978, helping develop and apply tools for understanding stormwater, wastewater, and combined sewer systems.
Helping across the full stormwater spectrum: SWMM (50+ years), InfoSWMM/ESRI (20 years), InfoWorks ICM (15 years), and the Autodesk AEC Collection (5 years)—and Grandpa (10 years).
My work connects hydrology, hydraulics, and water quality with the practical decisions engineers make every day: how to represent a drainage system, interpret a simulation, investigate unexpected results, and build confidence in a model.
SWMM5.org is where I share that experience through technical articles, modeling explanations, automation scripts, and interactive tools.
From SWMM Development to Everyday Modeling
My SWMM story began in 1973, when I went to the University of Florida intending to work on SWMM and took a class on it from Wayne Huber and James Heaney. I began working with them in 1977 and started working on SWMM itself in 1978.
I worked on SWMM 2.5, co-authored SWMM3 and EXTRAN 4, and was second author, with Wayne Huber, of SWMM4. I also contributed to the development of XPSWMM, ICM SWMM, and InfoDrainage. My career has included work at Innovyze and Autodesk as Project Director for InfoSWMM and InfoSewer, alongside collaboration with pioneers such as Wayne Huber, James Heaney, and Lew Rossman. I also spent three years at Autodesk with the title Autodesk Water Technologist—a name I’ve always liked.
Working on both software development and engineering applications has shaped how I approach modeling. I’m interested not only in what a program calculates, but also in how it calculates it—and what that means for the person using the results.
That perspective guides the material I publish here: explanations that connect model inputs, numerical behavior, and engineering interpretation.
Selected Contributions
- Worked on SWMM 2.5
- Co-author of SWMM3 and EXTRAN 4
- Second author, with Wayne Huber, of SWMM4
- Was part of the SWMM5 Crada between CDM and EPA
- Answered tens of thousands of questions on OpenSWMM.org
- Contributor to the development of XPSWMM, ICM SWMM, and InfoDrainage
- Project Director for InfoSWMM and InfoSewer at Innovyze and Autodesk
- Autodesk Water Technologist for four years
- Chair, SWMM5+ Technical Advisory Committee, Center for Infrastructure Modeling & Management (CIMM)
- EWRI Stormwater Modeling Committee for 8 Years
What SWMM Enablement Means to Me
SWMM enablement means removing whatever sits between an engineer and a working model.
My focus today is not writing the engine. Caleb and the OpenSWMM team carry that work forward, building on the foundation Lew Rossman and others established. My part is everything around it: compiling SWMM 5.2.4 to WebAssembly so it runs in a browser without an installation; decoding the .icmt and .iddx formats so a model is not trapped inside the software that created it; writing Ruby scripts that move a network from InfoSewer into InfoWorks ICM; and building free, interactive applications that show what the solver is doing instead of merely describing it.
After nearly five decades working with SWMM, I have learned that the engine is rarely the only obstacle. Often, it is the file you cannot open, the repetitive task that consumes an afternoon, the conversion that quietly drops an important assumption, or the result nobody checked.
Enablement is clearing those obstacles out of the way—making models more accessible, workflows more transparent, and results easier to question and verify—so the next engineer reaches the hydraulics faster than I did.
What You’ll Find on SWMM5.org
This site is a working reference for engineers, researchers, students, and software developers involved in urban drainage and water infrastructure.
SWMM Hydrology and Hydraulics
Explanations of rainfall-runoff processes, infiltration, routing, hydraulic controls, water quality, and the interactions that shape model results.
InfoWorks ICM and SWMM-Based Workflows
Practical discussions of network representation, simulation settings, solver behavior, and working across modeling environments.
Automation and Engineering Tools
Ruby scripting, model-data workflows, and interactive applications that help reduce repetitive work and make technical concepts easier to explore.
Model Verification and Troubleshooting
Approaches to investigating unexpected results, comparing simulations, checking assumptions, and understanding the limitations of a model.
Flood Modeling and Green Infrastructure
Topics connecting drainage networks, surface flooding, 1D/2D modeling, and green infrastructure to real-world engineering questions.
My Approach: Understand the Model, Not Just the Output
A completed simulation is the beginning of interpretation—not the end.
When reviewing a model, I return to a few fundamental questions:
- Does the network represent the physical system appropriately?
- Are the hydrologic and hydraulic assumptions suitable for the question being asked?
- Do continuity errors, numerical behavior, and time-step sensitivity warrant closer investigation?
- Can unexpected results be explained by the inputs, controls, boundary conditions, or solver behavior?
- Are the conclusions supported by the available data and the model’s limitations?
My goal is to help modelers move beyond accepting results toward understanding and explaining them.
Why I Share This Work
After more than five decades in urban drainage modeling, I still enjoy finding a clearer explanation, investigating an unusual result, or building a small tool that makes someone’s work easier.
This site brings together lessons from software development, engineering practice, technical discussions, and continued experimentation. Some articles explore a single parameter or equation; others connect broader ideas across hydrology, hydraulics, software, and engineering judgment.
The common purpose is practical: preserve useful knowledge and make it easier for the next modeler to find.
Explore the Resources
- Technical articles — modeling explanations, workflows, and troubleshooting.
- Interactive applications — browser-based tools for exploring engineering concepts.
- Ruby scripting resources — automation ideas and examples.
- Tools and resources — additional reference material.
Connect With Me
I welcome thoughtful questions, technical exchanges, and conversations about improving water modeling.