How things work: Inspecting underground stormwater storage

Important work is happening at Penn American and some is below ground. In the fall, staff from the Engineering Division inspected the underground stormwater storage system for the area. Most routine inspections of underground storm sewer systems are done with closed-circuit television cameras. In this case, a physical inspection was needed due to the large size of the structure. Entering confined spaces such as this requires planning and a number of safety precautions to protect the workers in these dangerous locations.

Underground systems are designed to trap sediments, but sediment levels cannot be observed and tracked from the surface. Inspections confirm if structures are functioning as designed and verify the system’s structural integrity.

The Penn American stormwater project won the American Public Works Association – Minnesota Chapter project of the year award in 2019. Water Resources Manager Bryan Gruidl has coordinated the project from concept to completion.

For more information, visit or call 952-563-8760.