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Lake Waubesa

Lake Waubesa is the third in the Yahara chain of lakes as the Yahara River flows south from Lake Monona through Upper Mud Lake. The watershed has a mix of urban and rural land use. Work in the Mendota and Monona watersheds to prevent phosphorus runoff is helping Lake Waubesa since much of the phosphorus in the lake flows from the upper lakes in the chain.

The north end of Lake Waubesa is surrounded by the Capital Spring State Recreation Area and features the new Lower Yahara River Trail and bike-pedestrian bridge. The south end of the lake receives spring water from Swan Creek, Murphy Creek and Bogholt Deep Spring, which buffers the high-quality Waubesa Wetlands from nutrient runoff. The outlet of the Yahara River sits at the east shore of the lake and runs south towards Lower Mud Lake before joining Lake Kegonsa. Goodland County Park on the western shore of the lake contains the only public beach on Lake Waubesa.

Most of the phosphorus entering the lake each year comes from the upper lakes via the Yahara River, although summer phosphorus levels may also be driven by runoff within the watershed (McDonald & Lathrop, 2016). Efforts to reduce the sources of upstream runoff will reduce the amount of phosphorus entering the lake via the Yahara River outlet (83% of the average annual phosphorus load).

The Yahara CLEAN plan for the Lake Waubesa Watershed calls for action to improve agricultural practices and improve control of construction erosion. Phosphorus reduction in the Lake Waubesa Watershed will come primarily from improving agricultural practices and improving control of construction erosion.

Lake Waubesa by the numbers

Lake Waubesa Watershed
Lake Waubesa Watershed

Lake Waubesa is a shallow lake, and water flushes through the lake relatively quickly (three months) compared to the deeper lakes.

  • Watershed area: 28,160 acres
  • Surface area: 2,080 acres
  • Shoreline: 9 miles
  • Maximum depth: 34 feet
  • Mean depth: 16 feet
  • Flushing rate: 2.8 months
Piers on Lake Waubesa
Piers on Lake Waubesa

How was the water (2019)?

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

Lake Waubesa 2019 Beach Closures

The beach at Goodland County Park was open all summer, likely due to the exclosure maintained by Dane County in 2019 to enhance the water quality at the beach. One Lake Waubesa beach is monitored.

2019 community projects & initiatives

  • Town of Dunn passed an assessment to allow for the purchase of development rights for the purpose of preserving agricultural land and natural areas.
  • Town of Dunn partnered with Lake Waubesa Conservation Association and Dane County Parks to offer a new leaf-collection site at Goodland County Park. This allowed an additional 780 cubic yards of leaves to be collected, bringing the total to 6,000 cubic yards of leaves for the 2019 season.
  • Friends of Capital Springs Recreation Area received a Foundation for Dane County Parks grant to develop educational and interpretive resources for an outdoor space at the Lussier Family Heritage Center.
leaf-collection-goodland
Leaf collection at Goodland County Park
Photo credit: Lake Waubesa Conservation Association

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

Organizations supporting Lake Waubesa

The following groups work on water quality issues in the Lake Waubesa watershed. Consider contacting an organization near you to get involved and let us know if we have missed your group.

Read about the other lakes in the Yahara Watershed

Here’s how Lake Waubesa faired in previous years:

How was the water?

In 2018, total phosphorus levels were “fair” and water clarity was “good” in the middle of the lake, according to DNR criteria, but the nine citizen monitor reports of cyanobacteria blooms were above the 4-year summer median of four.

Water clarity (2018 data)

  • 3.9 feet or "good" according to Department of Natural Resources criteria for shallow lakes
Lake Waubesa 2018 Median Clarity Chart
Source Dr. R. Lathrop, UW Center for Limnology
Data WDNR (1975-1994), NTL-LTER (1995-2018)

Phosphorus levels

  • 0.065 mg/L or "fair" according to Department of Natural Resources criteria for shallow lakes
Lake Waubesa 2018 Median Phosphorus Chart 
Source Dr. R. Lathrop, UW Center for Limnology
Data WDNR (1975-1994), NTL-LTER (1995-2018)

Beaches (2018 data)

  • Closed 22% of the time and open 78% of the time
  • 9 closure days due to cyanobacteria (blue-green algae)
  • 0 closure days due to E. coli bacteria
  • 0 closure days due to the combinations of cyanobacteria and E. coli
  • 13 closure days due to flooding

Based on data collected by Public Health Madison & Dane County, Lake Waubesa beaches were closed nine days from Memorial Day to August 20th, compared to the 2010-17 median of 15, all due to cyanobacteria. After August 20th, all the beaches were closed for the remainder of the season (August 21 – Labor Day) due to flood conditions.

What's new on Lake Waubesa?

Lake Waubesa summer water quality conditions are linked to the recent invasion of zebra mussels. The full effect of zebra mussels in the Yahara lakes is still uncertain. Results from other infested lakes suggest increases in water clarity in the middle of the lakes will occur. However, shoreline management problems could get worse from increased aquatic plant growth, and possible increases in filamentous algae and scums of cyanobacteria.

Summer water quality in 2018 was also impacted by the unusual amount of flow into and out of the lake resulting from above normal precipitation in the region.

Renewable natural gas off-loading station 
Renewable natural gas (RNG) off-loading station
Photo courtesy of Dane County

2018 Lake Waubesa projects

  • Dane County
    • Spent $5.5 million to build a renewable natural gas (RNG) off-loading station as part of a $28 million county RNG facility. Other RNG producers, like dairy digesters located north of Lake Mendota, can bring their fuel and inject it into the pipeline making it economically feasible to produce renewable energy and clean up our lakes
    • Permanently protected 35 acres in the southern Waubesa Wetlands Natural Resource Area
    • Installed an exclosure to improve Goodland County Beach water quality
  • Village of Cottage Grove restored a 1.5-acre wetland on the north edge of the village, called “Conservancy Court Wetland.”
  • Capital Area Regional Planning Commission worked with the University of Wisconsin-Madison to study the Waubesa Wetlands and make management recommendations. As a result of their study and community engagement, the Friends of Waubesa Wetlands was formed in 2018.
  • Friends of Waubesa Wetlands formed at the end of 2018 and held workdays throughout the year to remove invasive species and improve wildlife habitat.

Water clarity (2017)

  • 3.3 feet or "good" according to Department of Natural Resources criteria for shallow lakes

Phosphorus levels (2017)

  • 0.087 mg/L or "fair" according to Department of Natural Resources criteria for shallow lakes

Beaches (2017)

  • Open 79% of the time and closed 21% of the time
  • 21 closures days due to E. coli bacteria
  • No closures due to cyanobacteria (blue-green algae)

Lake Waubesa 2017 news

The Lake Waubesa beach at Goodland County Park was closed 21 times (out of a total 99 possible beach days), all due to high E. coli bacteria.

Water clarity (2016)

  • 3.6 feet or "good" according to Department of Natural Resources criteria for shallow lakes

Phosphorus levels (2016)

  • 0.044 mg/L or "good" according to Department of Natural Resources criteria for shallow lakes

Beaches (2016)

  • 1 closure due to E. coli bacteria
  • 10 closures due to cyanobacteria (blue-green algae)
  • 6 closures due to the combination of E. coli bacteria and cyanobacteria

Water clarity (2015)

  • 3.0 feet or "good" according to Department of Natural Resources criteria for shallow lakes

Phosphorus levels (2015)

  • 0.054 mg/L or "good" according to Department of Natural Resources criteria for shallow lakes

Beaches (2015)

  • 2 closures due to E. coli bacteria
  • 21 closures due to cyanobacteria (blue-green algae)
  • 10 closures due to the combination of E. coli bacteria and cyanobacteria

Water clarity (2014)

  • 2.8 feet or "fair" according to Department of Natural Resources criteria for shallow lakes

Phosphorus levels (2014)

  • 0.055 mg/L or "fair" according to Department of Natural Resources criteria for shallow lakes

Beaches (2014)

  • 7 closures due to E. coli bacteria
  • 5 closures due to cyanobacteria (blue-green algae)

Water clarity (2013)

  • 2.3 feet or "fair" according to Department of Natural Resources criteria for shallow lakes

Phosphorus levels (2013)

  • 0.066 mg/L or "fair" according to Department of Natural Resources criteria for shallow lakes

Water clarity (2012)

  • 1.6 feet or "fair" according to Department of Natural Resources criteria for shallow lakes

Phosphorus levels (2012)

  • 0.066 mg/L or "fair" according to Department of Natural Resources criteria for shallow lakes

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
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:

How was the water?

In 2018, total phosphorus levels and water clarity were “good” in the middle of the lake, according to DNR criteria. However, the six citizen monitor reports of cyanobacteria blooms were above the 4-year summer median of 7.5. Beaches were closed a record number of days, primarily due to cyanobacteria blooms.

Water clarity (2018 data)

  • 6.6 feet or “good” according to Department of Natural Resources criteria for deep lakes
Lake Monona 2018 Median Clarity Chart
Source Dr. R. Lathrop, UW Center for Limnology
Data WDNR (1975-1994), NTL-LTER (1995-2018)

Phosphorus levels (2018 data)

  • 0.030 mg/L or “good” according to Department of Natural Resources criteria for deep lakes
Lake Monona 2018 Median Phosphorus Chart 
Source Dr. R. Lathrop, UW Center for Limnology
Data WDNR (1975-1994), NTL-LTER (1995-2018)

Beaches (2018 data)

  • Closed 22% of the time and open 78% of the time
  • 44 closure days due to cyanobacteria (blue-green algae)
  • 4 closure days due to E. coli bacteria
  • 16 additional closure days due to both E. coli and cyanobacteria (blue-green algae)
  • 91 beach closure days due to flooding

In contrast to conditions in the middle of the lake, a large number of cyanobacteria blooms closed beaches located on the nearshore of the lake. According to data collected by Public Health Madison & Dane County, Lake Monona’s beaches were closed a record number of 64 days from Memorial Day to August 20th. The long-term median is 33 days for the whole summer. Beaches were closed primarily due to cyanobacteria or a combination of high E. coli and cyanobacteria. After August 20th, all the beaches were closed for the remainder of the season (August 21 – Labor Day) due to flood conditions.

Olbrich Beach Lake Monona

What’s new on Lake Monona?

Lake Monona summer water quality conditions are now linked to the recent invasion of zebra mussels. The full effect of zebra mussels in the Yahara lakes is still uncertain. Results from other infested lakes suggest increases in water clarity in the middle of the lakes will occur. However, shoreline management problems could get worse from increased aquatic plant growth, and possible increases in filamentous algae and scums of cyanobacteria.

Summer water quality in 2018 was also impacted by the unusual amount of flow into and out of the lake. Increased flows were the result of above normal precipitation in the region.

2018 Lake Monona projects

  • Dane County granted funds to City of Madison for an Ultra Low-Dose Alum Pilot. The pilot project is a collaboration with the University of Wisconsin-Madison to assess the effectiveness of adding a trace amount of aluminum sulfate. Alum is added to detention basins to prevent phosphorus from leaching from captured sediment. It is a chemical that binds to phosphorus, making it unavailable for algae growth.
  • City of Madison
    • Completed work on the Jacobson Furey Pond near Starkweather Creek and Dondee Pond near Highway 51 and Cottage Grove Road
    • Repaired river banks at Heritage Prairie Greenway
    • Constructed nine terrace rain gardens and expanded public messaging about leaf-free streets
  • City of Monona
    • Removed phosphorus-laden sediment from Winnequah Park Lagoon
    • Added 29 storm drains to their “Adopt a Storm Drain and Leaf Management Program”
    • Cleaned one-third of the city’s inlet catch basins Friends of Starkweather Creek held monthly outings to spark interest in the creek. The city also restored areas near the Dixon Greenway, Washington Manor Park, and Eken Park with native plantings.
 
“Adopt a Storm Drain” project – inlet mural near Monona Public Library
Photo courtesy of City of Monona

Water clarity (2017)

  • 5.1 feet or "good" according to Department of Natural Resources criteria for deep lakes

Phosphorus levels (2017)

  • 0.037 mg/L or "fair" according to Department of Natural Resources criteria for deep lakes

Beaches (2017)

  • Open 93% of the time and closed 7% of the time
  • 5 closure days due to E. coli bacteria; 27 closure days due to cyanobacteria (blue-green algae)
  • 19 additional closure days at Olbrich Park due to both E. coli and cyanobacteria (blue-green algae)

Lake Monona 2017 news

Lake Monona's beaches were closed 51 days out of the total 693 possible beach days (99 days multiplied by 7 beaches), mostly due to cyanobacteria or a combination of high E. coli and cyanobacteria. Olbrich Beach lost the most beach days. These closures were higher than the long-term median for the lake.

Water clarity (2016)

  • 6.2 feet or "good" according to Department of Natural Resources criteria for deep lakes

Phosphorus levels (2016)

  • 0.022 mg/L or "good/excellent" according to Department of Natural Resources criteria for deep lakes

Beaches (2016)

  • 24 closure days due to E. coli bacteria
  • 2 closure days due to cyanobacteria (blue-green algae)
  • 0 closure days due to the combination of E. coli and cyanobacteria (blue-green algae)

Water clarity (2015)

  • 4.6 feet or "fair" according to Department of Natural Resources criteria for deep lakes

Phosphorus levels (2015)

  • 0.026 mg/L or "good" according to Department of Natural Resources criteria for deep lakes

Beaches (2015)

  • 35 closure days due to E. coli bacteria
  • 0 closure days due to cyanobacteria (blue-green algae)
  • 0 closure days due to the combination of E. coli and cyanobacteria (blue-green algae)

Water clarity (2014)

  • 4.1 feet or "fair" according to Department of Natural Resources criteria for deep lakes

Phosphorus levels (2014)

  • 0.030 mg/L or "good" according to Department of Natural Resources criteria for deep lakes

Beaches (2014)

  • 20 closure days due to E. coli bacteria
  • 6 closure days due to cyanobacteria (blue-green algae

Water clarity (2013)

  • 3.6 feet or "fair" according to Department of Natural Resources criteria for deep lakes

Phosphorus levels (2013)

  • 0.026 mg/L or "good" according to Department of Natural Resources criteria for deep lakes

Water clarity (2012)

  • 4.9 feet or "fair/good" according to Department of Natural Resources criteria for deep lakes

Phosphorus levels (2012)

  • 0.027 mg/L or "good" according to Department of Natural Resources criteria for deep lakes

Water quality monitoring

2017 results from our monitoring program

Overview

Figure 1. 2017 monitoring sites (Red: Near-shore; Blue: Off-shore).

From Memorial Day to Labor Day, volunteers at piers and beaches around the five Yahara lakes measured near-shore water clarity, air and water temperature, and noted several visual observations.

Visual observations included presence of algal blooms (green/blue-green), floating plant debris, swimmers, waterfowl, wave intensity, and general water appearance.

Volunteers were asked to log condition reports at least weekly on our website, lakeforecast.org, where all data are updated in real time.

Read More

Monarch butterfly

About the talk

Monarch butterfly populations have been declining over the last 20 years. Because insect numbers are notoriously difficult to assess, and because they often show large annual fluctuations, simply documenting this decline has been a challenge. It is now important to move beyond simple documentation, and toward responding to the challenge posed by monarch conservation, and insect conservation in general. I’ll describe the amazing biology of migratory monarch populations, and then discuss how the need for an “all hands on deck” approach to monarch conservation is galvanizing habitat restoration across North America, including along fragile waterways.

Clean Lakes Alliance will be handing out our FIRST set of 5-year monitoring awards for our citizen monitors that have participated from 2013-2017!

About our speaker

Karen Oberhauser is the Director of the UW-Madison Arboretum. She and her students have conducted research on several aspects of monarch butterfly ecology. Her research depends on traditional lab and field techniques, as well as the contributions of a variety of audiences through citizen science. Her strong interest in promoting a citizenry with a high degree of scientific and environmental literacy led to the development of a science education program that involves courses for teachers, and opportunities for youth to engage in research and share their findings with broad audiences.

In 1996, Karen started a nationwide Citizen Science project called the Monarch Larva Monitoring Project, which continues to engage hundreds of volunteers throughout North America. Karen has authored over 90 papers on her research on monarchs, insect conservation, and citizen science. Her new job at the Arboretum blends her work on habitat conservation, public outreach, and citizen science research.

Karen is passionate about the conservation of the world’s biodiversity, and believes that the connections her projects promote between monarchs, humans, and the natural world promote meaningful conservation action. She is the chair of the Monarch Joint Venture, and a founding officer of the Monarch Butterfly Fund. In 2013, Karen received a White House Champion of Change award for her work with Citizen Science.

About the series

Yahara Lakes 101 is a series of educational events open to the public and a great chance for residents to learn more about the science behind the issues that affect our lakes. Each month we feature a different expert to make the science accessible and interesting to non-technical audiences.

The series is produced in partnership with the UW-Madison Nelson Institute for Environmental Studies, with hosting sponsor The Edgewater, presenting sponsor First Weber Group, supporting sponsor The Evjue Foundation, and media sponsor The Isthmus.

The event is held both indoors and outdoors (weather permitting) at The Edgewater. Come at 7:30 a.m. for a meet-and-greet and to enjoy your coffee, pastries, and fruit. The program begins at 8 a.m., and class is dismissed by 9 a.m. Complimentary event parking will be available at The Edgewater.

Admission is FREE for Friends of Clean Lakes. If you are not a Friend, admission is $10 per event. Registration for each event is requested for all attendees.

Stop the spread of invasive species sign

April 11, 2018 @ 3:00 am – 4:00 am

Stop the spread of invasive species sign
About the talk Join us for Yahara Lakes 101 on Wednesday, April 11th for a special talk on invasive species in our lakes. Susan Graham will speak about the scale of the problem, what Wisconsin is doing, what YOU can do to help. We’ll learn about what invaders could be next and what success has looked like right here in Wisconsin. Aquatic invasive species, otherwise known as “AIS,” are non-native species that can take over, spread primarily by humans, and negatively impact recreation, the economy, and our native ecosystems. Wisconsin has a comprehensive rule called “NR-40” that classifies species that are prohibited, restricted, or not a concern, and guides regulations based on risks. For the Wisconsin DNR, preventing the spread of invasive species relies on a social science understanding of human behavior. Susan Graham has worked on lake-related issues for 25 years at the Wisconsin DNR and is a great resource for anyone wanting to learn more. Don’t miss this talk! About our speaker Susan Graham earned her master’s degree in Water Resources Management from the University of Wisconsin-Madison Nelson Institute for Environmental Studies. She has worked on a variety of lake-related issues in her 25 years at Wisconsin DNR, including water quality assessment, coordinating the statewide Citizen Lake Monitoring Network, and serving on committees to establish phosphorus standards for lakes. Susan is currently the Lakes Coordinator for DNR’s southcentral region, where she works on aquatic plant management along with monitoring, grants, and policy for lakes and aquatic invasive species. Susan is also part of a team that is creating a tool to prioritize response efforts to invasive species on public lands and waters. Sue is an avid organic gardener and hiker, and loves swimming and paddling when there isn’t ice coating our waters. About the series Yahara Lakes 101 is a series of educational events open to the public and a great chance for residents to learn more about the science behind the issues that affect our lakes. Each month we feature a different expert to make the science accessible and interesting to non-technical audiences. The series is produced in partnership with the UW-Madison Nelson Institute for Environmental Studies, with hosting sponsor The Edgewater, presenting sponsor First Weber Group, supporting sponsor The Evjue Foundation, and media sponsor The Isthmus. The event is held both indoors and outdoors (weather permitting) at The Edgewater. Come at 7:30 a.m. for a meet-and-greet and to enjoy your coffee, pastries, and fruit. The program begins at 8 a.m., and class is dismissed by 9 a.m. Complimentary event parking will be available at The Edgewater. Admission is FREE for Friends of Clean Lakes. If you are not a Friend, admission is $10 per event. Registration for each event is requested for all attendees.

Details

Date:
April 11, 2018
Time:
3:00 am – 4:00 am
Cost:
$10
Event Category:
Website:
http://cleanlakesalliance.isthmustickets.com/events/51449316/yahara-lakes-101-science-cafe

Organizer

Clean Lakes Alliance
Phone
(608) 255-1000
Email
info@cleanlakesalliance.org
Website
View Organizer Website

The Edgewater

1001 Wisconsin Place
Madison, WI 53703 United States + Google Map
(608) 535-8200
View Venue Website

Love in the Lakes - Yahara Lakes 101

About the talk

Organisms across the globe are faced with the same dilemma – how to pass on their genes to the next generation and give their youngsters the best possible chance at success. Things are no different for the creatures in the Madison-area lakes. Pike, panfish, plants, and invertebrates all go to great lengths to find love, but take wildly different approaches. What makes each strategy successful, and why? During this presentation, you’ll learn about the mating and reproductive strategies of several important species, which range from the heartwarming… to the bizarre.

About our speakers

Justin began his career in water resources hauling laundry baskets of invasive weeds from the muddy Charles River in Boston, MA. Despite the smell, he found he loved working with water, and moved to Madison in 2013 to pursue a master’s degree in Water Resources Management from UW-Madison. Since 2014 Justin has worked for Clean Lakes Alliance in many capacities, including surveying lake users, supporting the citizen water quality monitoring program, making maps, and analyzing water quality data. He is currently employed by the Department of Natural Resources in the Water Monitoring section. In his free time, Justin enjoys ice fishing and paddling on the Madison lakes and beyond.

About the series

Yahara Lakes 101 is a series of educational events open to the public and a great chance for residents to learn more about the science behind the issues that affect our lakes. Each month we feature a different expert to make the science accessible and interesting to non-technical audiences.

The series is produced in partnership with the UW-Madison Nelson Institute for Environmental Studies, with hosting sponsor The Edgewater, presenting sponsor First Weber Group, supporting sponsor The Evjue Foundation, and media sponsor The Isthmus.

The event is held both indoors and outdoors (weather permitting) at The Edgewater. Come at 7:30 a.m. for a meet-and-greet and to enjoy your coffee, pastries, and fruit. The program begins at 8 a.m., and class is dismissed by 9 a.m. Complimentary event parking will be available at The Edgewater.

Admission is FREE for Friends of Clean Lakes. If you are not a Friend, admission is $10 per event. Registration for each event is requested for all attendees.

Water Quality Monitoring

2017 monitoring season

What started in 2013 as a handful of Clean Lakes Alliance board members testing the water has now grown into a network of over 70 volunteers doing weekly water quality monitoring on all five lakes.

Each week this summer, our team of monitors gathered data on water clarity and temperature. They also made visual observations on beach conditions and identified potentially harmful cyanobacteria (blue-green algae) blooms. And what a summer it was!

Read More

Lake Mendota

Lake Mendota is the largest and deepest lake in the Yahara chain of lakes. The lake is surrounded by mostly agricultural land with areas of rapid urban growth.

The north end of the Yahara Watershed, to the north of Lake Mendota, is known for fertile soils and multi-generational dairy farms. The University of Wisconsin-Madison and the Madison downtown lie along the southern shore of Lake Mendota, although much of the isthmus and downtown area drains into Lake Monona or Lake Wingra.

Major tributaries feeding into Lake Mendota include, from west to east, Pheasant Branch Creek, Dorn Creek, Sixmile Creek, the Yahara River, and Token Creek. Nutrients that flow into the later are carried down the chain of lakes via the Yahara River and represent the largest source of excess nutrients in the lower lakes.

Maple Bluff Beach on Lake Mendota
Maple Bluff Beach on Lake Mendota

In urban areas of the Mendota Watershed, most of the phosphorus reductions will come from better controls on construction erosion, leaf management, and stabilizing waterway banks to reduce erosion. In rural areas, most phosphorus reduction will come from improved agricultural practices including cropping and nutrient management.

To improve water quality in Lake Mendota, the Yahara CLEAN plan calls for reducing phosphorus runoff from both urban and rural areas. Improvements to reduce phosphorus loading into the lae will help improve water quality in the other three lakes in the chain (Monona, Waubesa, and Kegonsa) by reducing the amount of phosphorus flowing to the lower lakes via the Yahara River.

Lake Mendota Watershed
Lake Mendota Watershed

Lake Mendota by the numbers

The lake is 82 feet at its deepest, known as the “deep hole” between Picnic Point and Maple Bluff. Water in Lake Mendota moves slowly, replenishing every 4.4 years.

  • Watershed area: 72,094 acres
  • Surface area: 9,842 acres
  • Shoreline: 22 miles
  • Public beaches: 8
  • Maximum depth: 82 feet 
  • Mean depth: 42 feet
  • Flushing rate: 4.4 years

How was the water (2019)?

A reproducing population of zebra mussels was first confirmed in the lake in 2015. Zebra mussels filter out small forms of free-floating algae (phytoplankton), making the water clearer at the center of the lake, but prefer not to eat cyanobacteria, helping this organism proliferate near the shoreline. They are most likely contributing to increases in cyanobacteria blooms, beach closures, and the accumulation of algal mats that wash up on downwind shorelines.

Zebra mussels
Zebra mussels

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

Lake Mendota Total Phosphorus at Fall Turnover 2019

Lake Mendota Total Phosphorus at Fall Turnover (surface measurement, 1975-2019). Fall turnover is when the lake mixes from top to bottom due to temperature changes in the water. This is the time when phosphorus concentrations are most uniform in the lake. Concentrations were low during 2010-2017. Concentrations went up in both 2018 and 2019 due to high phosphorus loading from the lake’s major tributaries.
Lake Mendota 2019 Beach Closures

Lake Mendota beaches were closed 63 times during the summer of 2019, primarily due to cyanobacteria blooms or both cyanobacteria and high E. coli (64%). A total of eight Lake Mendota beaches are monitored.

2019 Community projects & initiatives

  • City of Middleton repaired damage to the Donna Drive Pond, including reinforcing the embankment, improving the outlet system, and enlarging the pond to provide more flood-storage capacity.
  • Friends of Pheasant Branch Conservancy is continuing to work with the City of Middleton and Dane County to repair and restore the Pheasant Branch Creek corridor after it was impacted by the devastating floods of August 20-21, 2018.
  • Dane County provided funding for a new “Continuous Cover Program” to offer small family farms an incentive to convert lands from annual row crops into perennial grasses to improve water quality and reduce flooding.
  • Town of Westport completed a project to control bank erosion along Six Mile Creek, a Lake Mendota tributary stream.
  • Village of DeForest constructed five bio-retention basins at the Conservancy Place Athletic Complex. Wetland restorations continued at the Marvin and Marie Schweer’s Natural Area and along the Upper Yahara River Trail.

Organizations supporting Lake Mendota

The following groups work on water quality issues in the Lake Mendota watershed. Consider contacting an organization near you to get involved!

Read about the other lakes of the Yahara Watershed

Here’s how Lake Mendota faired in previous years:

How was the water?

In 2018, total phosphorus levels and water clarity were “good” in the middle of the lake, according to DNR criteria. However, the 18 citizen monitor reports of cyanobacteria blooms were above the 4-year summer median of 7.5.

Lake Mendota Median Water Clarity level for 2018
Source Dr. R. Lathrop, UW Center for Limnology
Data WDNR (1975-1994), NTL-LTER (1995-2018)

Phosphorus levels (2018 data)

  • 0.025 mg/L or “good” according to DNR criteria for deep lakes
Lake Mendota 2018 Median Phosphorus level  
Source Dr. R. Lathrop, UW Center for Limnology
Data WDNR (1975-1994), NTL-LTER (1995-2018)

Beaches (2018 data)

  • Closed 23% of the time and open 77% of the time
  • 60 closure days due to cyanobacteria (blue-green algae)
  • 7 closure days due to E. coli bacteria
  • 11 closure days due to cyanobacteria and E. coli
  • 104 closure days due to flooding

In contrast to the conditions in the middle of the lake, a large number of cyanobacteria blooms closed beaches located on the nearshore of the lake. Based on data collected by Public Health Madison & Dane County, Lake Mendota beaches were closed a record number of 78 days from Memorial Day to August 20th, compared to the summer 2010-17 median of 35 days for the whole summer. After August 20th, all the beaches were closed for the remainder of the season (August 21 – Labor Day) due to flood conditions.

Cyanobacteria Lake Mendota 
Cyanobacteria spotted on Lake Mendota at James Madison Park, 2018

What’s new on Lake Mendota?

Lake Mendota summer water quality conditions are now linked to the recent invasion of zebra mussels. The full effect of zebra mussels in the Yahara lakes is still uncertain. Results from other infested lakes suggest increases in water clarity in the middle of the lakes will occur. However, shoreline management problems could get worse from increased aquatic plant growth, and possible increases in filamentous algae and scums of cyanobacteria. Summer water quality in 2018 was also impacted by the unusual amount of flow into and out of the lake resulting from above normal precipitation in the region.

Zebra mussels 
Zebra mussels

2018 Lake Mendota projects

  • Dane County, Yahara WINS, and Clean Lakes Alliance continued support for a pilot project at nine farms testing manure composting. The project by Yahara Pride Farms will reduce pathogens and help farmers manage manure in the winter by composting instead of winter spreading.
  • Yahara Pride Farms continued to implement cost-effective, farmer-led practices to protect soil and water quality. YPF also piloted innovative practices like manure composting.
  • Dane County
    • Worked with farmers to implement practices that divert phosphorus from the lake
    • Granted funds to help permanently protect 95.5 wetland acres near the Fishery Area and to help purchase a 100.9 acre farm, with 10.9 acres purchased and easements on 90 acres for the Cherokee Marsh Natural Resource Area
    • Permanently protected 11 acres in Token Creek County Park and Natural Resource Area
    • Removed 2.7 miles of phosphorus-laden legacy sediment from Dorn Creek as part of the “Suck the Muck” project
    • Began construction on a $1.6 million nutrient concentration system at the Middleton digester. The digester will further treat and filter manure utilizing reverse osmosis technology, and reduce the risk of phosphorus runoff
  • City of Madison approved $2.36 million to purchase a 31-acre addition to Cherokee Marsh
  • Village of DeForest
    • Constructed 12 public/private stormwater facilities, maintained a 40-acre wetland in the Marvin & Marie Scheweers Natural Area, and restored wetlands in Reigstand Park
    • Maintained a high-quality sedge meadow along the Yahara River Trail

Friend group projects for the watershed

  • Friends of Cherokee Marsh maintained 95 acres with a prescribed burn at Yahara Heights Park and continued to collect critical information on stream health as part of the Yahara WINS volunteer monitoring program.
  • Friends of Pheasant Branch Conservancy evaluated the feasibility of a carp bubble barrier system in Pheasant Branch Creek through a Clean Lakes Grant.
  • The UW-Madison Lakeshore Nature Preserve worked with staff to remove woody invasive plants from 17 acres, sow native seed on 11 acres, and control invasive garlic mustard plants on more than 50 acres of the 300-acre reserve.
Bubble Barrier Survey on Pheasant Branch Creek, 2018 
Friends of Pheasant Branch Conservancy evaluate the feasibility of a carp bubble barrier system in Pheasant Branch Creek

Water clarity (2017)

  • 4.9 feet or "good" according to DNR criteria for deep lakes

Phosphorus levels (2017)

  • 0.036 mg/L or "fair" according to DNR criteria for deep lakes

Beaches (2017)

  • Open 96% of the time and closed 4% of the time
  • 7 closure days due to E.coli bacteria
  • 24 closures due to cyanobacteria (blue-green algae)
  • After an excellent 2016 beach season, Lake Mendota’s beaches lost 31 out of a total 792 possible beach days in 2017 (99 days multiplied by 8 beaches), which is a return to the long-term median. Closures were primarily due to cyanobacteria (blue-green algae); Tenney Beach and the Memorial Union Pier lost the most days.

Lake Mendota 2017 news

The explosion of zebra mussels was the big news for Lake Mendota, which has the potential to drastically change the lake and its shoreline. According to scientists at the UW Center for Limnology, we can likely expect more green, filamentous algae to grow in thick mats along the shoreline (read "Zebra mussel invasion in full swing in Lake Mendota"; "Zebra mussels transforming depths of Lake Mendota")

Other big news was the 2017 blue-green algal bloom that colored Lake Mendota from Picnic Point to the Yahara River and into Lake Monona on Father's Day weekend. According to the Center for Limnology, the warm, calm conditions and phosphorus levels created the perfect conditions for the bloom and resulting fish kill (read "Madison in Bloom: Blue-green algae hits Lake Mendota.")

With these changes in lake ecology, managing runoff will be more important than ever to mitigate the impact of zebra mussels and blue-green algae.

Water clarity (2016)

  • 7.2 feet or "good/excellent" according to DNR criteria for deep lakes

Phosphorus levels (2016)

  • 0.022 mg/L or "good/excellent" according to DNR criteria for deep lakes

Beaches (2016)

  • 8 closure days due to E. coli bacteria
  • 0 closures due to cyanobacteria (blue-green algae)
  • 0 closures due to the combination of E. coli and cyanobacteria

Water clarity (2015)

  • 4.9 feet or "good" according to DNR criteria for deep lakes

Phosphorus levels (2015)

  • 0.030 mg/L or "good" according to DNR criteria for deep lakes

Beaches (2015)

  • 28 closure days due to E. coli bacteria
  • 20 closures due to cyanobacteria (blue-green algae)
  • 1 closure due to the combination of E. coli and cyanobacteria

Water clarity (2014)

  • 4.9 feet or "good" according to DNR criteria for deep lakes

Phosphorus levels (2014)

  • 0.030 mg/L or "good" according to DNR criteria for deep lakes

Beaches (2014)

  • 28 closure days due to E. coli bacteria
  • 20 closures due to cyanobacteria (blue-green algae)

Water clarity (2013)

  • 4.6 feet or "fair" according to DNR criteria for deep lakes

Phosphorus levels (2013)

  • 0.026 mg/L or "good" according to DNR criteria for deep lakes

Water clarity (2012)

  • 5.6 feet or "good" according to DNR criteria for deep lakes

Phosphorus levels (2012)

  • 0.018 mg/L or "excellent" according to DNR criteria for deep lakes

2016 State of the Lakes Annual Report

Luck from “Mother Nature”

MADISON, Wis. — Today at the sixth annual Save Our Lakes community breakfast, Clean Lakes Alliance released the 2016 State of the Lakes Annual Report. The report looks at phosphorus reduction efforts through the 2016 calendar year. It shows as a community, progress is being made. Phosphorus is the root cause of algae – just one pound of the nutrient is capable of producing 500 pounds of algae.

“2016 was a great year. The water was as clear as it’s been in a long time in our lakes, but we got lucky,” said Clean Lakes Alliance Executive Director James Tye. “A slow spring melt and fewer intense rain events meant phosphorus-rich runoff to our lakes was down, but it shows us if we control runoff regularly, we can impact our lake clarity.”

Read More

Mike Parsen

Learn more about the science behind the issues that affect our lakes!

About the talk

Based on past surveys, roughly 25% of Dane County’s tested wells contained nitrate in excess of the state and federal drinking maximum contaminant level (MCL) of 10 mg/L for nitrate – well above Wisconsin’s statewide exceedance level of 12 percent. This study was designed to improve our understanding of the spatial and temporal distribution of nitrate in groundwater by combining GIS mapping, groundwater modeling, and statistical analysis. Findings demonstrated that while spatial groundwater nitrate patterns have remained fairly stable over time, driven by a combination of land use and hydrologic setting; there have been slight improvements in groundwater quality. While results indicate that maximum nitrate concentrations indeed appear to be decreasing, minimum background concentrations continue to rise; leading to an increased equilibrium level of nitrate in groundwater.

About our speaker

Mike Parsen is a hydrogeologist with the Wisconsin Geological and Natural History Survey, part of UW-Extension. Mike received his undergrad in Geology and Geological Engineering from the UW-Madison and his Master’s in Hydrogeology and Water Resources Management from the University of Neuchatel in Switzerland. Mike is currently is working on hydrogeology projects in Dane, Chippewa, Kewaunee, Trempealeau, Dunn, and Eau Claire Counties, serves as a resource on industrial sand mining in Wisconsin, and collaborates closely with the U.S. Geological Survey and DNR to operate, maintain, and manage the Wisconsin Groundwater-Level Monitoring Network.

About the series

Yahara Lakes 101 is a series of educational events open to the public and a great chance for residents to learn more about the science behind the issues that affect our lakes. Each month we feature a different expert to make the science accessible and interesting to non-technical audiences. Yahara Lakes 101 is produced in partnership with the UW-Madison Nelson Institute for Environmental Studies, with hosting sponsor The Edgewater, presenting sponsor First Weber Group, supporting sponsor The Evjue Foundation, and media sponsor The Isthmus.

Yahara Lakes 101 is held both indoors and outdoors (weather permitting) at The Edgewater. Come at 7:30 a.m. for a meet-and-greet and to enjoy your coffee, pastries, and fruit. The program begins at 8 a.m., and class is dismissed by 9 a.m.

If you already are a Friend of Clean Lakes (minimum $35 donation/year), then admission is free. Become a Friend today. If you are not a Friend yet, admission is $10 per event. Registration for each event is requested for all attendees. Special event parking will be available at The Edgewater.

Join us today

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