How Clean is the River?

The Upper Mississippi River Basin Association (UMRBA) is the Governor-established forum for interstate water resource planning and management on the Upper Mississippi River, representing its member states of Illinois, Iowa, Minnesota, Missouri, and Wisconsin.   UMRBA published its second assessment of water quality on the Upper Mississippi River System, the “How Clean is the River?” report, which presents trends between 1989 and 2018.  
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This new report underscores the value of coordinated and comprehensive water quality monitoring and management on the Upper Mississippi River System, while revealing where future work is needed.  

In reporting from the Mississippi River Ag and Water Desk on the Investigate Midwest website, the Milwaukee Journal Sentinel reports summarizes five major take-aways from the report in trends from 1989 to 2018:

• The Upper Mississippi River is getting saltier
• Monitoring showed mixed progress on reducing nitrogen and phosphorus, which cause algae blooms
• Sediment in the water decreased, creating better habitat for plants and animals
• Metal concentrations decreased, aside from some hotspots
• Data gaps make it tougher to tease out trends

The Minneapolis Star Tribune's January 21, 2024 article, Health Checkup for the River, states, "A new report tracks pollution in the upper river and a major tributary. It finds good news on lead, phosphorus and sediments, and troubling trends on chloride, nitrogen and some gaps in data collection."   

Extensive algae growth in Mississippi River backwaters. Photo - Minneapolis Star Tribune Jan 21, 2024

The first and continuing mission of the LWV Upper Mississippi River Region was to work to lessen nutrient loading to the Upper Mississippi.  As such, we follow reports like this closely.  In this report, the analysis shows that there has been progress in some parts of the river in reducing nutrients, but other areas nitrogen and phosphorus continue to increase.  

UMBRA summarizes the findings of the report in more detail:
Positive Trends

• Total phosphorus concentrations have decreased in the Upper Mississippi River above Pool 13 (near Bellevue, Iowa)              
• Total and inorganic nitrogen have decreased in the La Grange Pool of the Illinois River      
•  Total suspended solids have decreased significantly throughout the Upper Mississippi River System            
•  Dissolved oxygen concentrations have increased throughout the Upper Mississippi River System

 
Negative Trends

• Concentrations of chloride and sulfate have increased throughout the Upper ​Mississippi River System
• Total nitrogen appears to be increasing above Pool 13 (near Bellevue, Iowa), however the trend has low confidence   
• Total phosphorus is increasing in Upper Mississippi River Pool 15 (near Rock Island, Illinois) 
• Lead has increased in the Upper Mississippi River Pools 15 (near Rock Island, Illinois) and 17 (near New Boston, Illinois), but levels area below the chronic aquatic life use threshold

 
Data Gaps

• Water quality monitoring frequency, sampling methods,
• and laboratory analytical methods are not consistent across the Upper Mississippi River System
• Metals data and emerging contaminants data is not collected sufficiently for analyzing trends
• Important data gaps continue to reduce our ability to effectively identify problems and target management actions to protect water quality

Minding the Gaps:
Description of the UMRBA monitoring strategy, from the UMRBA website - 
"UMRBA's Interstate Water Quality Monitoring Strategy facilitates coordinated and comprehensive water quality monitoring for the Upper Mississippi River.  Probabilistic and fixed site sampling are designed to support the states' ability to determine whether Clean Water Act goals are being met related to four major designated uses (aquatic life, drinking water, fish consumption, recreation).  ... ​The states are committed to integrating and utilizing existing program data and information to the greatest extent possible and anticipate working closely with other programs in data sharing.  Several federal, state, and regional programs conduct significant water quality monitoring.  Those efforts are designed to meet their own objectives, none of which are capable of supporting the states' Clean Water Act (CWA) purposes and that cover the river’s full spatial extent."

In 2014, the UMRBA developed a monitoring strategy for the Mississippi River main stem.  All of UMRBA's five states are committed to this Interstate WQ Monitoring Strategy, both in terms of supporting the creation of the monitoring plan and securing implementation funding.  Although the monitoring is designed to determine whether the mandates of the Clean  Water Act are being met, there is not dedicated federal funding to support the monitoring.  Minnesota, Wisconsin, and Illinois monitor on the Upper Mississippi River mainstem through their state specific ambient monitoring programs. Iowa and Missouri do not have mainstem monitoring through their state ambient monitoring programs.

In 2016-2017 UMRBA piloted the monitoring plan on shared borders between the Twin Cities and La Crosse, Wisconsin. In 2020-2021, the shared borders between Lock and Dam 17 to Lock and Dam 21 (including Iowa, Missouri, and Illinois state agencies) were sampled. UMRBA and the five states are planning to sample its fixed site network on the Upper Mississippi River (12 sites from Lock and Dam 2 to Thebes, Illinois) will be sampled starting October 2025 through September 2026.  This will continue implementation of portions of UMRBA’s monitoring plan, but federal funding to fully implement and operationalize UMRBA’s monitoring plan is needed to create long term datasets for the UMR and address current data gaps in monitoring.  ​