Muskegon Lake Water Quality Dashboard


water quality monitoring

The Muskegon Lake Long-Term Monitoring Program began in 2003, in an effort to observe and document changes in the ecological health of Muskegon Lake and provide the data needed to remove Muskegon Lake from the list of Great Lakes Areas of Concern (AOC). As part of the program, the lake is sampled 3 times per year at 6 sites for a suite of biological, physical, and chemical parameters.

Muskegon Lake buoy observatory

As a complement to the long-term monitoring program, the Muskegon Lake Observatory was established in 2011. The observatory consists of a buoy system that collects continuous water quality, hydrology, and meteorological data during the ice-free period.

Key water quality indicators were selected from these datasets to create a water quality dashboard for Muskegon Lake. The goal of the dashboard is to provide a visual representation of the current status and historical trends in Muskegon Lake water quality, by rating each indicator along a scale from desirable (green) to undesirable (red) conditions. Each scale also includes a category that indicates the water quality goal for the lake is being met (yellow).

The indicators shown below are commonly used to assess water quality. We selected total phosphorus, chlorophyll a, Secchi disk depth, and dissolved oxygen to assess lake status, from among the many parameters that we monitor. Each indicator is described in more detail below.

The data indicate that Muskegon Lake’s water quality in 2019 declined from 2018; some indicators were suggestive of undesirable conditions, indicating the lake’s ecological health, while certainly improved from the industrial era (Steinman et al. 2008; Liu et al. 2018), still has room for improvement.


Total Phosphorus

2019 Mean Concentration: 29 µg/L
Target Concentration: 30 µg/L


Current Status (2019)

TP dashboard

Total Phosphorus Concentration, μg/L

Total phosphorus concentration increased from 2018 to 2019 and qualified for the Meeting Goal status. TP concentrations have been desirable for the prior 8 years, indicative of positive lake restoration.

Historical Status (1972, 2003-2019)

TP dashboard

Data sources: Freedman et al. (1979); Muskegon Lake Long-term Monitoring Program, Steinman et al. (2008) and AWRI (unpublished data)

As one of the key nutrients that fuels algal growth, phosphorus concentration can indicate the potential for a lake to sustain undesirable algal blooms. The phosphorus dashboard was created by calculating annual average total phosphorus (TP) concentrations measured in the surface water of the 6 long-term monitoring stations. Historical data collected by the US EPA (Freedman et al. 1979) are included as a reference point for historical conditions.


Chlorophyll a

2019 Mean Concentration: 15.2 µg/L (monitoring program)
2019 Mean Concentration: 7.98 µg/L (buoy)
Target Concentration: 10 µg/L


Current Status (2019)

Chl dashboard

Chlorophyll a Concentration, μg/L

Mean chlorophyll a concentration increased from 2018 to 2019 and its current status remains Undesirable, as the average concentration in 2019 was above the water quality goal, largely due to sampling during a summer algae bloom. Mean chlorophyll a from the Muskegon Lake Observatory (2 m depth), taken every 15 min from May through October, but with multi-week chlorophyll a sensor downtime periods in June and July, was 7.98 (± 3.28) µg/L, revealing the temporal variability of this indicator.

Historical Status (1972, 2003-2019)

Chl dashboard

Data sources: Freedman et al. (1979); Muskegon Lake Long-term Monitoring Program, Steinman et al. (2008) and AWRI (unpublished data)

Chlorophyll a is the green pigment found in photosynthetic algae. Measuring chlorophyll a is one way to estimate the amount of algal biomass present in lake water. The chlorophyll a dashboard was created by calculating annual average chlorophyll a concentrations measured in the surface water of the 6 long-term monitoring stations. Historical data collected by the US EPA (Freedman et al. 1979) are included as a reference point for historical conditions.


Secchi Disk Depth (Water Clarity)

2019 Mean Depth: 2.04 m
Target Depth: 2.0 m


Current Status (2019)

Secchi dashboard

Secchi Depth (Water Clarity), m

The current status for the Secchi depth indicator falls within the Meeting Goal category, meaning that the average Secchi depth in 2019 was within acceptable range of the water quality goal (i.e., somewhat clear). Increased clarity in Muskegon Lake may be due to filtering by dreissenid (i.e., zebra and quagga) mussels.

Historical Status (1972, 2003-2019)

Secchi dashboard

Data sources: Freedman et al. (1979); Muskegon Lake Long-term Monitoring Program, Steinman et al. (2008) and AWRI (unpublished data)

Secchi disk depth is an estimate of water clarity, measured using a standard black and white disk. Low water clarity can be the result of algal biomass, suspended particulate matter, or natural staining of the water. The Secchi depth dashboard was created by calculating annual average Secchi depths measured at the 6 long-term monitoring stations. Historical data collected by the US EPA (Freedman et al. 1979) are included as a reference point for historical conditions.


Dissolved Oxygen

2019 Mean % Days < 2 mg/L: 14%
Target Mean % Days < 2 mg/L: 25%


Current Status (2019)

DO dashboard

Low Dissolved Oxygen (<2 mg/L): Bottom Waters, % Monitoring Period (May-October)

The current status of the dissolved oxygen indicator falls within the Meeting Goal category, meaning that the percentage of days with low DO in 2019 was within the acceptable range of time. The buoy bottom water (11 m) DO sensor operated for ~70% of the 2019 monitoring season, compared to 47% of the 2018 season and 84-97% in 2011-2017.

Historical Status (2011-2019)

DO dashboard

Data source: Muskegon Lake Observatory, B. Biddanda (unpublished data)

Well-oxygenated water is critical to the healthy functioning of aquatic ecosystems, including sustaining populations of fish and bottom-dwelling organisms, such as insects, worms, mollusks, and snails. In overly-productive (i.e., eutrophic) lakes, dissolved oxygen (DO) can become depleted in the bottom waters, particularly during summer months. The DO dashboard was created by calculating the percentage of time during the annual monitoring period (May-October) that the daily average DO was less than 2 mg/L in the bottom waters at the Muskegon Lake Observatory buoy.


Acknowledgements

We are very grateful to the many people associated with collecting the data on Muskegon Lake that help inform this dashboard, including Bopi Biddanda, Mike Hassett, Maggie Oudsema, Brian Scull, Terry Boerson, Tim Halloran, Eric Hecox, Emily Kindervater, Jasmine Mancuso, Rachel Orzechowski, James Rahe, Ian Stone, Autumn Taylor, Tony Weinke, and Sean Woznicki.

We also gratefully acknowledge the Community Foundation for Muskegon County and the National Oceanic and Atmospheric Administration (NOAA) for helping to fund the monitoring efforts in Muskegon Lake.


References

Freedman, P., R. Canale, and M. Auer. 1979. The impact of wastewater diversion spray irrigation on water quality in Muskegon County lakes. U.S. Environmental Protection Agency, Washington, D.C. EPA 905/979006-A.

Liu, B., McClean, C.E., Long, D.T., Steinman, A.D., and R.J. Stevenson. 2018. Lake eutrophication and recovery over a 200-year period of post-native American settlement was determined by a complex set of local and regional factors. Science of the Total Environment 628-629: 1352-1361.

Steinman, A.D., M. Ogdahl, R. Rediske, C.R. Ruetz III, B.A. Biddanda, and L. Nemeth. 2008. Current status and trends in Muskegon Lake, Michigan. Journal of Great Lakes Research 34: 169-188.