Leveraging PCSWMM to Improve Neighborhood Floodplain Modeling

Iain T. Gordon, EIT, Project Engineer, Timmons Group

Kelsey R. Redman, EIT, Project Engineer, Timmons Group

Neighborhood residential and structural flooding is one of the worst aspects of any significant rainfall event. In undersized drainage systems, even a small downpour can quickly flood streets, yards, and seep into the homes of unsuspecting citizens. Municipalities are often faced with the challenge of improving localized flooding in these areas with limited knowledge on which components of a drainage system exacerbate this flooding. Figuring out what specifically causes the flooding in these areas can often be challenging to quickly assess using traditional hydrologic and hydraulic analyses. Intensively modeling these flooding scenarios can greatly improve a locality’s ability to understand what is causing the flooding and can provide information on targeted flood prevention measures for the study area.

However, modeling these areas can sometimes be tricky, as residential neighborhoods are usually flat with a combination of ditch and piped drainage infrastructure. This makes it difficult to use traditional riverine and piped network modeling methods to study these areas. These methods can be time-consuming, as riverine modeling requires acute detail for residential systems, and the modeling existing piped drainage networks becomes complex as study area increases.

A Stormwater Management Model, specifically the PCSWMM software, offers an elegant solution to these issues with its ability to integrate modeling methods that route runoff through piped, riverine, channelized, and impounded systems. This presentation will explore the benefits that PCSWMM has to offer when performing preliminary drainage studies. Specifically, the discussion will focus on the in-house GIS tools built into the program and the user-friendly interface that allows for quick iterations to improve models and better understand the flood conditions.

Author Bio

Iain Gordon is a Project Engineer with Timmons Group. He has 3 years of experience in the field of stormwater engineering with primary responsibilities that include hydrologic and hydraulic analysis, dam failure modeling, inundation mapping and floodplain study preparation.

Kelsey Redman is an EIT with Timmons Group. She has 1 year of experience in the field of stormwater engineering with primary responsibilities that include storm sewer design, hydrologic and hydraulic analysis, inundation mapping and floodplain study preparation.