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Escherichia coli Monitoring and Assessment in 2022 and 2023 After Beach Restoration at Lake St. Clair Metropark Beach, Macomb County, Michigan

Scientific Investigations Report 2026-5134
Prepared in cooperation with Michigan Department of Environment, Great Lakes, and Energy
By: , , and 
https://doi.org/10.3133/sir20265134

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Abstract

Lake St. Clair Metropark Beach in Michigan has a history of closures because of elevated Escherichia coli (E. coli) concentrations in its recreational waters. To reduce closures, restoration projects were implemented in 2021 to deter waterfowl from congregating on the beach. In this study, the U.S. Geological Survey, in cooperation with the Michigan Department of the Environment, Great Lakes, and Energy and in collaboration with Huron- Clinton Metroparks and the Macomb County Health Department, monitored E. coli from 2022–23 in surface water, shallow groundwater, and sediment at Lake St. Clair Metropark Beach. Results were compared to data from a prerestoration (2018–19) study. A significant decrease in daily geometric mean E. coli concentrations in surface water was observed postrestoration, but the number of high concentration events increased. This resulted in more frequent beach closures postrestoration. Surface- sediment E. coli concentrations significantly decreased after restoration, and waterfowl populations generally decreased from 2021 to 2023, suggesting that the deterrence measures could be influencing E. coli concentrations in surface sediments and surface water. Groundwater E. coli concentrations were orders of magnitude higher than those in surface water and revealed no change correlated with restoration. Seepage measurements indicated that groundwater occasionally discharges into surface water, potentially providing a transport mechanism for E. coli to reach the lake. Continued monitoring and consideration of environmental factors could help to better understand the beach system.

Suggested Citation

Lockmiller, H.A., Byers, V.C., and Fogarty, L.R., 2026, Escherichia coli monitoring and assessment in 2022 and 2023 after beach restoration at Lake St. Clair Metropark Beach, Macomb County, Michigan: U.S. Geological Survey Scientific Investigations Report 2026–5134, 24 p., https://doi.org/10.3133/sir20265134.

ISSN: 2328-0328 (online)

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Sample Collection Methods and Analysis 
  • Quality Assurance and Quality Control 
  • Escherichia coli Results after Beach Restoration Efforts 
  • Groundwater Seepage Rates
  • Gull and Geese Enumeration Results
  • Pre- and Postrestoration Escherichia coli Comparisons
  • Synthesis of Escherichia coli, Groundwater Seepage, and Waterfowl Enumeration Data at Lake St. Clair Metropark Beach
  • Summary
  • References Cited
Publication type Report
Publication Subtype USGS Numbered Series
Title Escherichia coli monitoring and assessment in 2022 and 2023 after beach restoration at Lake St. Clair Metropark Beach, Macomb County, Michigan
Series title Scientific Investigations Report
Series number 2026-5134
DOI 10.3133/sir20265134
Publication Date April 09, 2026
Year Published 2026
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Upper Midwest Water Science Center
Description Report: viii, 24 p.; Data Release; Dataset
Online Only (Y/N) Y
Additional Online Files (Y/N) N
Additional publication details