Stormwater project prioritization: using hydrologic modeling, water quality modeling, and infrastructure condition assessment to optimize investments

Aging public infrastructure is one of the greatest challenges facing stormwater utilities in the United States.  At the same time, there are additional demands to reduce flood risks associated with climate change and to meet surface water quality requirements.  With limited resources to address these sometimes-competing needs, a strategic approach is needed to identify and construct projects that capitalize on multiple opportunities.

The City of Minneapolis Public Works Department has initiated a program to identify and construct stormwater projects throughout the City.  The program uses data from three primary tools: hydrologic modeling, water quality modeling, and infrastructure risk assessment.  Although each of these tools were recently developed to address different issues (flooding, surface water quality, and infrastructure maintenance / replacement), the data generated by these tools is compiled to identify and rank areas where multiple benefits can be realized. Detailed studies are conducted on these priority areas to identify and construct favorable projects. This prioritization approach allows the City to leverage funding from multiple sources, provides a technical justification for project implementation, and constructs projects that can address multiple needs.  The defined process also empowers staff to clearly communicate work priorities to others including residents, politicians, and other city / government offices.

This presentation will describe the SWMM-based hydrologic / hydraulic models and the custom GIS-based water quality model that have been developed by the City.  The process used to identify priority areas using key data from models and other sources will be also be presented.  Finally, the benefits of using this process will be discussed.