Maintenance and Operations
Stormwater Drainage System
The City of Minneapolis owns and maintains many types of stormwater facilities, including:
- 600 miles of storm pipes
- Over 18,200 storm manholes
- Over 28,000 storm drains17 miles of large storm tunnels
- 25 stormwater pump stations
- 145 grit chambers
- 390 stormwater outlets
- At least 20 stormwater ponds and man-made wetlands
An inventory and condition assessment study was completed in 2012 for all Minneapolis storm tunnels. Results of that study produced a storm tunnel rehabilitation program, which makes needed repairs and improvements.
Proper maintenance and operation of the stormwater drainage system minimizes pollutants entering the Mississippi River and the lakes and creeks of Minneapolis. When it rains, streets act as collection channels, making them part of the stormwater drainage system. This system requires maintenance, including:
- Cleaning and repairing damage to storm pipes, storm drains and manholes
- Inspecting and maintaining pump stations, grit chambers and stormwater ponds
- Removal and proper disposal of sediment and nutrients (mostly sand and fertilizer) from storm drain structures. Storm drains and grit chambers are cleaned annually, removing trash and other materials.
In 2016 Minneapolis Sewer Operations personnel:
- Removed 320 cubic yards of sediment from stormwater grit chambers
- Removed 281 cubic yards of sediment was removed from storm drain tunnels
- Collected 3,173 tons of leaves for composting during the city-wide fall sweep
- Reclaimed 18,200 tons of material, mostly sand, during spring and summer street sweeping operations
Sanitary Sewer System
Protection of surface waters requires proper maintenance and operation of the sanitary sewer system. Minneapolis streets contain miles and miles of sanitary sewers; the earliest were built around 1870. Many of these brick sewers are still in operation, but some of the older concrete sewers require repair or replacement.
The City has an ongoing rehabilitation program designed to extend the life of these sewers by installing a fiberglass lining, which prevents groundwater contamination from leaky pipes.
Sanitary sewer pipes occasionally get blocked up, which can cause backups into basements. Regular cleaning of storm pipes helps prevent this. Also, Metropolitan Council Environmental Services (MCES) inspects and maintains most of the 31 miles of deep sanitary tunnels (also known as interceptors) in Minneapolis. These deep tunnels convey sanitary sewage to the Metropolitan Wastewater Treatment Plant.
Garbage, sediment, and other contaminants are deposited on roadways from a number of factors including:
- Over-application of salt
- Animal waste
- Erosion from construction sites
Public and private snow and ice control operations contribute to this problem. City crews apply thousands of tons of sand and salt to roadways every year to help manage snow and ice control. This can be problematic because pollutants can bind to sand particles, disturbing the ecosystem of water bodies, where salt is harmful to both groundwater and surface water. This sand and salt can wash into the Mississippi River and the lakes and creeks of Minneapolis without proper control measures:
- Regular street sweeping, performed each spring, summer and fall
- Proper application of deicing materials
- Proper housekeeping practices for deicing material storage, including covering salt stockpiles to minimize potential groundwater contamination and runoff
- Properly application of erosion control measures to help control runoff from sand stockpiles
Last updated Jan 28, 2019