Lake Monona

Lake Monona

Lake Monona is the second lake in the Yahara chain of lakes. The land surrounding the lake is mostly urban and is fed by the Yahara River, Wingra Creek, and Starkweather Creek.

Over the years, Lake Monona has faced water quality issues from urban runoff and from industrial sites. Besides the Yahara River, the largest source of phosphorus coming into Lake Monona is from Starkweather Creek. Most of the land surrounding and directly draining to the lake is urban. The Yahara CLEAN plan for the Lake Monona Watershed calls for action to improve leaf management and reduce erosion from construction sites.

Lake Monona map

Lake Monona by the numbers

The land between Lake Mendota and Lake Monona forms Madison’s iconic isthmus. Madison is one of only two major U.S. cities to be located on an isthmus. (The other city is Seattle, Washington.) Lakes Monona and Mendota are the only lakes in the Yahara chain classified as “deep” by the Wisconsin Department of Natural Resources criteria.

  • Watershed area: 61,643 acres
  • Surface area: 3,274 acres
  • Shoreline: 13 miles
  • Maximum depth: 64 feet
  • Mean depth: 27 feet
  • Flushing rate: 9.5 months

How was the water (2019)?

2019 average (July – August) water clarity and phosphorus concentrations both ranked “fair,” according to Wisconsin DNR criteria for deep lakes.

Lake Monona 2019 Beach Closures

Lake Monona beaches were closed 48 times during the summer of 2019, primarily due to cyanobacteria blooms or both cyanobacteria and high E. coli (75%). A total of seven Lake Monona beaches are monitored.

2019 Community projects & initiatives

  • City of Madison improved stormwater management at Nautilus and Jacobson Fury Ponds, and made streambank repairs along Daley Drive and Tree Lane. The City also restored natural areas by planting pollinator prairies along Inner Drive and established native plants around Dondee Pond. The City collected approximately 1,600 additional tons of leaves compared to the five-year average, and continued its Expanded Erosion-control Enforcement Program.
  • City of Monona dredged North Winnequah Park Lagoon, stabilized the lagoon’s shoreline, installed new fish-habitat features, and expanded an adopt-a- storm drain program. In total, the City has had 110 drains adopted by volunteers to keep them free of leaves and dirt.
  • Friends of Starkweather Creek began working with the Capital Area Regional Planning Commission on a Starkweather Creek Watershed chloride study, collaborated with partners to maintain the rain garden at Washington Manor Park, and removed invasive vegetation from along the creek corridor.
Jacobson Fury Pond

Per- and poly-fluoroalkyl substances (PFAS) were found in high concentrations at Truax Field and in nearby Starkweather Creek in 2019. The Wisconsin DNR issued a fishing advisory on Lake Monona to limit consumption of and exposure to the contaminant.

PFAS Advisory Sign
PFAS advisory sign at Olbrich Park on Lake Monona

For an update on the latest phosphorus reduction projects within the watershed, see the State of the Lakes Annual Report.

Organizations supporting Lake Monona

The following groups work on water quality issues in the Lake Monona watershed.

City of Madison
City of Monona
Dane County
Friends of Monona Bay
Friends of Starkweather Creek
Madison Water Utility
Public Health Madison & Dane County
Yahara Watershed Improvement Network
Friends of the Yahara River Parkway

Read about the other lakes of the Yahara Watershed

Here’s how Lake Monona faired in previous years: