Flooding

The City has constructed a variety of projects over the years to help reduce flooding in neighborhoods and on streets. Additionally, the City does a number of annual, biannual and by each rain event preventative maintenance cleanings to keep stormwater sewers and waterways clear so the infrastructure moves water through the system effectively. Below, find a number of ways the City works to maintain stormwater infrastructure and see some of the recent projects that have been constructed.

Ongoing Stormwater System Maintenance

Annual maintenance

• Willow Creek Basin Cleaning
  • City Engineering has a basin on University Avenue that collects rainwater. In Spring of 2018, Engineering crews removed 305 cubic yards of debris.
• Biannual Catch Basin Cleaning
  • In April and October of every year, City crews clean catch basins in the City. During this clean, on average, crews clean approximately 1,200 structures and clear, on average, 480 tons of debris, per season since 2016.
• Priority Grate Cleaning
  • After and prior to rain events, City crews clear 763 structures of debris which allows stormwater to flow through them more effectively. Priority Grates would include anything from inlets to dead ends and big grates on large storm sewer.
• ~10 miles of storm sewer built/replaced annually
• Streets Division maintenance by the numbers for 2021:
  • Total miles swept (when sweeping the City multiple times): 58,684
  • Total tonnage of debris collected: 6,473
• Greenway mowing/debris removal – all the stuff we do to maintain our system in an attempt to keep the conveyance system clean.

Current Projects

In addition to the annual maintenance activities listed above, the City designs and constructs larger flood mitigation projects.  See the links below for some of the current and completed projects.

• Hawk’s Landing Flood Mitigation
• Lower Badger Mill Creek Pond
• Mendota-Grassman Greenway Flood Mitigation and Restoration
• McKenna Boulevard Flood Mitigation Project
• Sauk Creek Greenway Restoration
• Southwest Bike Path/Waite Circle Culvert Reconstruction
• University Avenue Relief Pipe Phase II

Past Projects

University Avenue Relief Storm Sewer

The University Avenue Relief Storm sewer consists of 96-inch pipe and 10 foot by 6 foot box culvert that extends from Grand Avenue to Willow Creek.

The pipe was installed in four phases, which occurred in 2003, 2004, 2011 and 2013.

The purpose of this sewer is to divert water from a 12 foot by 6 foot storm sewer box, located beneath University Avenue and installed in 1925. The 1925 box was known to be undersized, even for the time, but costs prohibited construction of the full design, which proposed two 12 foot by 6 foot storm boxes. In the years following the original construction, the street corridor filled with other utilities and eliminated the possibility of fitting additional storm capacity beneath University Avenue. Therefore, the relief pipe was installed along the southern embankment of Campus Drive. Diverting water from the 1925 box creates additional capacity in the system, allowing University Avenue to drain more rapidly.

Park Edge Drive Flood Mitigation

The Park Edge Drive Flood Mitigation was designed to address stormwater sewer overflows within an easement where the public stormwater sewer was constructed through a condominium association property. The capacity of the stormwater sewer would run full during large rain events and significantly reduce parking lot surface drainage which caused flooding issues within the private property.

City Engineering worked with the property owner to create an easement and move the stormwater sewer main to the driveway and route toward the Greentree South Section Greenway. City Engineering increased the pipe sizes and capacity of the new stormwater sewer routed through the new easement and converted the old public main for private parking lot drainage use.  The project was completed in 2017.

Bram Street Pond

Stormwater runoff from Alliant Energy Center’s parking lot drains to the west to Lykberg Park and the Bram Street area. Residents on Bram Street experience flooding at times of high lake levels and major rain events.

To help control the runoff from the Alliant Energy Center parking area, Dane County dedicated a storm and drainage easement over a portion of Lyckberg Park which allowed the City of Madison to design and construct a pond for detention and storm water quality purposes.

Due to the limited easement area, the pond was designed to provide detention in the ten-year design storm event. Storm sewer and vain drains were extended into the Alliant Energy Center parking lot to divert storm water to the pond, cutting off a portion of the parking lot from draining directly to Bram Street.

The project was completed in 2014.

Impact Fees for Drainage and Stormwater

• LBMC
• UBMC
• Valley View
• West side drainage
• Mineral Pont Rd drainage