What’s under the street?
If you think of a street as a layer cake, the asphalt is the frosting. However, much more lies beneath the street’s surface: critical infrastructure such as water pipes, deep storm water tunnels, wastewater pipes, electric lines, gas lines, telecommunications cables and more sit below the surface to help residents and businesses operate every day.
An illustration of what lies beneath the street’s surface on Hennepin.
Hennepin Avenue is one of the major reconstruction projects underway in downtown Minneapolis. It's being reconstructed from Washington Avenue South to 12th Street. The redesign will make the street more functional for all travel modes.
The downtown section of Hennepin Avenue was last rebuilt in 1986. After more than 30 years, the pavement is worn out and needs to be replaced. Updates to aging infrastructure, such as the 1880s-era sanitary sewer system, will be made. Private utility work is also being coordinated to support a growing city.
The underground infrastructure
Drinking water: The water main under Hennepin is part of the City's impressive network of more than 1,000 miles of water mains. The Minneapolis Public Works Water Treatment and Distribution Services pumps approximately 21 billion gallons of water from the Mississippi River each year. It produces an average of 57 million gallons of drinking water each day -- a rate that could fill Lake of the Isles in about four days.
Crews install a new water main at 11th and Hennepin.
Waste water: Sanitary sewer pipes are also underneath the street. The city has over 800 miles of sanitary sewers -- infrastructure that ensures that sewage is safely transported to the Metropolitan Wastewater Treatment Plant in St. Paul to be treated. Wastewater from over 100,000 buildings in Minneapolis runs through the sanitary sewers to the treatment plant.
Sections of the new sanitary sewer pipe being installed under Hennepin as part of the reconstruction project.
Storm sewer and storm tunnel: The City also maintains over 500 miles of storm pipes and 12 miles of deep storm tunnels that transport rain water and snow melt into bodies of water throughout the city. The pipes drain to the Mississippi River, creeks and lakes in Minneapolis.
Telecommunications: Companies are installing upgraded facilities and infrastructure to support the growing demand for fiber and wireless to deliver internet, phone and television communications.
Electricity: In downtown Minneapolis, Xcel Energy maintains thousands of miles of underground cables, five substations (including an underground one), 515 transformers in 215 underground vaults, and about 1,500 manholes. While the City is reconstructing Hennepin Avenue, Xcel Energy is relocating some of its underground infrastructure like power lines and transformers to aid the City’s construction work. The company is also using this opportunity to install additional infrastructure to ensure reliability for future development in the area.
Natural gas: CenterPoint Energy maintains over 900 miles of natural gas pipeline serving 133,000 homes and businesses in Minneapolis. Recent construction activity includes: completed replacement of all cast iron and bare steel gas mains, replacing the 20 to 24-inch Belt Line that serves hundreds of thousands of homes in the metro, and continuing to relocate meters from inside to outside of residential properties.