MMSD Freshwater Resources Monitoring: 2024 Annual Summary

MMSD's Freshwater Resources Monitoring group conducts routine surface water monitoring at nearly 100 fixed monitoring sites within our planning area and Lake Michigan. Field measurements and grab samples are taken at these sites in all weather conditions and brought to the in-house certified laboratory to be analyzed for almost 40 different parameters.

To summarize the large amount of data collected each year, the Freshwater Resources Monitoring group produces an annual report that highlights a specific subset of parameters and/or sites. This year’s report focuses on the percentage of results complying with surface water quality criteria for dissolved oxygen (DO), Escherichia coli (E. coli), total phosphorus (TP), and total suspended solids (TSS). Monitoring these parameters together provides a comprehensive picture of water quality, identifying potential issues, including risks to human health and habitat degradation.

Overall percent compliance in 2024 was very similar to that of 2023. However, total phosphorus and total suspended solids were compliant 8-9% less of the time in 2024.

It is worth noting that both of those parameters are greatly influenced by precipitation, and the midwest was both abnormally wet and abnormally dry at different parts of the year (NOAA National Centers for Environmental Information, Annual Drought Report, January 2025).