As the City of Lakes, Minneapolis is known for its ample and beautiful lakes. Without a dedicated effort to preserve and protect these urban waters, our lakes would not be the valuable resources that they are today. The Minneapolis Park & Recreation Board’s (MPRB) lake water quality monitoring program was implemented in 1991 as part of a diagnostic study for the Chain of Lakes Clean Water Partnership. We currently monitor 13 lakes within the City of Minneapolis:

Lake Conditions

We make some monitoring data available throughout the season so you have an idea of lake conditions:

  • The Lake Aesthetic and User Recreational Index (LAURI) is a summary of conditions that affect recreation on each lake.
  • Updated Secchi disk readings indicate the current clarity of each lake.
  • We monitor beaches during the summer to determine if there are any health risks to swimmers. Weekly data indicates:
    • E. coli levels
    • Current water temperature
    • Open/closed status of the beaches

Aquatic Invasive Species

Aquatic invasive species are often the most visible sign of change in lakes, and many problem species are very difficult to remove or even limit. We carefully monitor these species in cooperation with various state agencies and work to limit their spread where possible.

About Secchi Disk Readings

secchi diagram

To measure water transparency with a Secchi disk, the disk is lowered from the shaded side of a boat until it cannot be seen. The depth of the water is recorded at the point where the disk reappears upon raising it from its original depth beyond visibility. It is important to remember that the Secchi measurement is a simple, approximate measurement of water clarity and can be influenced by various factors such as time of day, reader’s eyesight, water color and suspended particles in the water. Therefore, Secchi disk readings should be used as a comparative tool to determine trends between lakes and over time.

  • Increased water clarity may be due to reduced nutrient inputs, seasonal algal cycles, decreased sediment inputs, and zooplankton grazing on algae.
  • Decreased water clarity may be due to large algal blooms, increased soil erosion inputs, wind circulation of sediments and nutrients, stormwater inputs, or a decrease in zooplankton.

Secchi readings for the lakes are done during the regular lake sampling schedule, with some lakes sampled every other year.

Recent Secchi Disk Readings

Brownie Lake

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Bde Maka Ska

August 22, 2019
Secchi Depth (feet): 7.2

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August 22, 2019
Secchi Depth (feet): 7.2

July 25, 2019

Secchi Depth (feet): 12.89

July 11, 2019

Secchi Depth (feet): 12.27

June 18, 2019

Secchi Depth (feet): 17.7

June 5, 2019

Secchi Depth (feet): 18.4

May 22, 2019

Secchi Depth (feet): 21.26

May 14, 2019

Secchi Depth (feet): 31.8

April 19, 2019

Secchi Depth (feet): 4.0

Cedar Lake

August 19, 2019
Secchi Depth (feet): 1.5

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August 19, 2019
Secchi Depth (feet): 1.5

July 23, 2019

Secchi Depth (feet): 3.44

July 8, 2019

Secchi Depth (feet): 3.18

June 17, 2019

Secchi Depth (feet): 6.9

June 3, 2019

Secchi Depth (feet): 6.9

May 20, 2019

Secchi Depth (feet): 3.51

May 6, 2019

Secchi Depth (feet): 2.6

April 16, 2019

Secchi Depth (feet): 2.7

Lake Harriet

August 22, 2019
Secchi Depth (feet): 5.2

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August 22, 2019
Secchi Depth (feet): 5.2

July 29, 2019

Secchi Depth (feet): 7.61

July 11, 2019

Secchi Depth (feet): 10.02

June 19, 2019

Secchi Depth (feet): 12.1

June 5, 2019

Secchi Depth (feet): 14.9

May 23, 2019

Secchi Depth (feet): 20.11

May 14, 2019

Secchi Depth (feet): 32.5

April 19, 2019

Secchi Depth (feet): 4.6

Lake Hiawatha

August 23, 2019
Secchi Depth (feet): 3.0

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August 23, 2019
Secchi Depth (feet): 3.0

July 26, 2019

Secchi Depth (feet):  4.4

July 12, 2019

Secchi Depth (feet): 5.21

June 20, 2019

Secchi Depth (feet): 5.0

June 6, 2019

Secchi Depth (feet): 7.1

May 23, 2019

Secchi Depth (feet): 3.25

May 16, 2019

Secchi Depth (feet): 5.3

April 23, 2019

Secchi Depth (feet): 4.4

Lake of the Isles

August 19, 2019
Secchi Depth (feet): 1.3

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August 19, 2019
Secchi Depth (feet): 1.3

July 23, 2019

Secchi Depth (feet): 2.40

July 8, 2019

Secchi Depth (feet): 4.53

June 17, 2019

Secchi Depth (feet): 7.3

June 3, 2019

Secchi Depth (feet): 7.8

May 20, 2019

Secchi Depth (feet): 5.81

May 6, 2019

Secchi Depth (feet): 3.1

April 16, 2019

Secchi Depth (feet): 2.3

Loring Pond

August 21, 2019
Secchi Depth (feet): 2.9

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August 21, 2019
Secchi Depth (feet): 2.9

July 24, 2019

Secchi Depth (feet): 1.05

July 10, 2019

Secchi Depth (feet): 3.12

June 19, 2019

Secchi Depth (feet): 3.4

June 4, 2019

Secchi Depth (feet): 7.8

May 21, 2019

Secchi Depth (feet): 4.36

May 7, 2019

Secchi Depth (feet): 2.4

April 18, 2019

Secchi Depth (feet): 2.5

September 24, 2018

Secchi Depth (feet): 10.1

September 10, 2018

Secchi Depth (feet): 2.9

August 23, 2018

Secchi Depth (feet): 6.3

August 9, 2018

Secchi Depth (feet): 8.5

July 26, 2018

Secchi Depth (feet): 9.1

July 10, 2018

Secchi Depth (feet): 8.0

June 21, 2018

Secchi Depth (feet): 6.6

June 5, 2018

Secchi Depth (feet): 12.9

May 24, 2018

Secchi Depth (feet): 12.3

May 7, 2018

Secchi Depth (feet): 3.1

Lake Nokomis

August 23, 2019
Secchi Depth (feet): 2.4

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August 23, 2019
Secchi Depth (feet): 2.4

July 26, 2019

Secchi Depth (feet): 2.49

July 12, 2019

Secchi Depth (feet): 3.87

June 20, 2019

Secchi Depth (feet): 5.8

June 6, 2019

Secchi Depth (feet): 10.3

May 23, 2019

Secchi Depth (feet): 4.07

May 15, 2019

Secchi Depth (feet): 3.1

April 23, 2019

Secchi Depth (feet): 2.1

Powderhorn Lake

August 21, 2019
Secchi Depth (feet): 1.8

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August 21, 2019
Secchi Depth (feet): 1.8

July 24, 2019

Secchi Depth (feet): 4.79

July 10, 2019

Secchi Depth (feet): 3.67

June 19, 2019

Secchi Depth (feet): 2.8

June 4, 2019

Secchi Depth (feet): 5.1

May 21, 2019

Secchi Depth (feet): 2.3

May 7, 2019

Secchi Depth (feet): 1.7

April 18, 2019

Secchi Depth (feet): 1.6

Spring Lake

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July 10, 2019

Secchi Depth (feet): 2.20

June 4, 2019

Secchi Depth (feet): 3.1

Wirth Lake

August 20, 2019
Secchi Depth (feet): 6.1

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August 20, 2019
Secchi Depth (feet): 6.1

July 22, 2019

Secchi Depth (feet): 7.09

July 8, 2019

Secchi Depth (feet): 11.45

June 17, 2019

Secchi Depth (feet): 15.1

June 3, 2019

Secchi Depth (feet): 11.3

May 21, 2019

Secchi Depth (feet): 8.53

May 6, 2019

Secchi Depth (feet): 4.5

April 16, 2019

Secchi Depth (feet): 3.3

Brownie Lake 2018

View more Brownie Lake monitoring data

Bde Maka Ska 2018

View more Bde Maka Ska monitoring data

Cedar Lake 2018

View more Cedar Lake monitoring data

Diamond Lake 2018

View more Diamond Lake monitoring data

Lake Harriet 2018

View more Lake Harriet monitoring data

Lake Hiawatha 2018

View more Lake Hiawatha monitoring data

Lake of the Isles 2018

View more Lake of the Isles monitoring data

Loring Pond 2018

View more Loring Pond monitoring data

Lake Nokomis 2018

View more Lake Nokomis monitoring data

Powderhorn Lake 2018

View more Powderhorn Lake monitoring data

Wirth Lake 2018

View more Wirth Lake monitoring data

Citywide 2017

lauri graph citywide

Long-term monitoring is important because lakes can change from year to year due to wet or dry weather and we can only see trends when we put years of data together. Analysis of this data tells us if the water quality is improving or not.

View the MPRB Water Resources Report for detailed annual monitoring data, data collection methods, and more.