Waterways in the Milwaukee River basin continue to fall short on phosphorus standards, according to a recent report from a volunteer water quality monitoring group.
The ninth annual report from Milwaukee Riverkeeper finds the health of the Milwaukee, Menomonee and Kinnickinnic rivers fell between 2017 and 2018, driven by last year’s historic rainfall, aging infrastructure and various human impacts. The report’s authors note the decline was seen in both urban and rural areas.
By sourcing data from a network of more than 80 volunteer community scientists at over 200 different sites, the group analyzes factors such as water temperature, levels of phosphorus, chloride and dissolved oxygen and other variables.
All three of the individual watersheds in the region failed to meet phosphorus standards for the third year in a row, the report shows. Meanwhile, chloride “persists as a growing issue,” with related water quality indicators meeting fewer targets last year than in 2017.
Still, the report’s overall grade for chloride levels is relatively favorable, compared to the much lower grades for phosphorus and bacteria. Cheryl Nenn, who heads up monitoring and restoration efforts for Milwaukee Riverkeeper, says the lower rating for 2018 is “somewhat disappointing” but adds that policy changes and restoration pushes have made a positive impact.
“It took many decades for our rivers to become polluted, and it’s going to take many decades to bring them back to a healthy state,” she said. “We are seeing some positive trends at the local site and subwatershed level, as well as some improving long-term trends.”
Local efforts include habitat restoration and “stream remeandering projects” to redirect waterways, as well as river access improvements. The report highlights work being done by community groups and municipalities to improve river quality in southeastern Wisconsin.
Overall, the Milwaukee River basin has around 875 total miles of rivers, 18 miles of trout streams and 403 miles of “impaired waters,” which don’t meet certain water quality standards. The waterways pass by both farmland and expanding cities, and the report shows water quality impacts differ at various locations.
In the northern part of the watershed, agricultural activity directly leads to higher phosphorus concentrations. And in the more populated southern region, higher levels of stormwater runoff from cities carries pollutants into nearby channels.
Report authors say last year’s heavy rains likely contributed to runoff from farms and led to higher phosphorus levels. Associated outcomes include toxic algae blooms, fish kills and oxygen depletion, which makes it harder for many forms of underwater life to survive.
Meanwhile, chloride in water can kill fish during periods of high concentration, which can occur after road salt is washed into the river systems. The group says the report’s findings “reaffirm the need for better winter deicing application and updated best management practices that reduce the amount of road salt being put onto roads.”
Over the past decade, Milwaukee Riverkeeper has escalated its monitoring efforts, but report authors note that some of the tributaries in the watershed aren’t included due to a lack of available monitors. Still, the organization analyzed more than four times as much data in 2018 than in the prior year.