Assessment of MCES Sanitary Interceptor Tunnels in Minneapolis and St. Paul-Video

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The Metropolitan Council manages wastewater infrastructure across seven Minneapolis–St. Paul counties, including roughly 34 miles of sandstone tunnels. Brierley Associates assessed the tunnels’ risks using historic drawings, inspection reports, GIS data, geology, and surrounding land uses. The Minneapolis assessment quantitatively ranked eight tunnels to identify the five highest-risk segments. Because St. Paul had less complete information, its assessment focused more qualitatively on specific locations and conditions.<br /><br />The studies documented caves, unlined or deteriorating tunnels, undocumented drainage pipes, limited system redundancy, and infrastructure built close to or above the tunnels. Some sections carry heavy urban, rail, or river-related loads. The team recommended targeted inspections, additional investigations, hydraulic and emergency-response planning, improved redundancy where feasible, and maintaining the collected information as a living asset-management resource. The goal is to address information gaps and prioritize practical interventions rather than assume that a massive capital project is immediately necessary.

Keywords

wastewater infrastructure

tunnel risk assessment

Metropolitan Council

asset management

Minneapolis Saint Paul