Photo courtesy of the Milwaukee Metropolitan Sewerage District
The Deep Tunnel
The project came online in 1993 and was designed to keep sewer overflows to a minimum. It has succeeded, reducing 50 to 60 annual overflows per year to less than 25.
Stormwater
Stormwater results from rain running off of streets, yards, roofs and parking lots. Occasionally the regional sewer system is overwhelmed by flows from the local sewers. When this happens, flows are diverted to the Deep Tunnel for storage until there is room at treatment plants to clean the excess wastewater.
Overflows
Overflows occur when a storm provides more rainwater than the system can handle. These overflows can occur even when the Deep Tunnel is not at full capacity.
Clean Water Act
The 1972 legislation gave the Environmental Protection Agency the legal authority to create standards for pollution control. The act provided federal funding for sewage treatment plants.
Southeast Wisconsin Regional Planning Commission
The regional government agency is responsible for the Regional Water Quality Management Plan for the greater Milwaukee watershed and provides other input for MMSD. The Commission maintains up-to-date reports on the current status of water quality in the region.
