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XPSWMM Modeling Update for South Loop Drainage District

Houston Engineering Project
XPSWMM Modeling Update for South Loop Drainage District

Location:  Bloomington, Minnesota
Client:  The City of Bloomington


HEI was selected by the City of Bloomington to update modeling for 19 sites throughout the city to reflect the recent redevelopments. The project is unique in that the work is located near the Mall of America in preparation for a Specialized World Expo event in 2027. Unfortunately, the US was not selected for the event, but the project still provided valuable information that will inform future planning for stormwater control.

The Project

HEI began the project by reviewing the 19 redeveloped sites that now include stormwater control measures to meet the City’s stormwater requirements. Once we identified the needed modifications to the XPSWMM model, the catchment re-delineation process began.

This process included updating the GIS catchments rather than only inputting data values into the model. Our team either re-computed the inputs in GIS or updated them from stormwater management reports for the 19 sites. The hydraulic network was updated with primarily underground storage, given the requirements from the neighboring MSP Airport. Special attention was given to the “Adjacent Lands” site, which required a large amount of compensatory storage. HEI assessed the impacts of reduced storage with the updated model and recommended mitigation measures.

HEI identified the most critical flooding locations to address and vetted them with the City. Goals and design criteria were also drafted to steer the identification of opportunity sites. In-house automated tools were implemented for identifying cost-effective locations for stormwater control, resulting in a priority heatmap. From the heatmap, HEI identified and assessed the feasibility of eight regional storage projects, developing an overall map of the opportunities, and providing written descriptions of their anticipated function. Our team performed preliminary modeling to assess the impact of the top selected opportunities.

HEI also prepared a project report to document and describe the model updates, identified stormwater opportunities, associated flood reductions, costs, and recommendations.

Project Highlights

  • Provided updated and detailed XPSWMM modeling and flood inundation mapping for redevelopment in a high-traffic neighborhood, which can be used in future planning and flood mitigation efforts.
  • Implemented in-house automated tools to identify opportune locations for regional flood control facilities.
  • Provided project deliverables on-schedule despite the compressed timeline.