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Assessment of Groundwater Quantity and Quality Contributions to Lake Huron

Scientific Investigations Report 2026-5136
Prepared in cooperation with the Great Lakes Cooperative and Science Monitoring Initiative
By: , , and 
https://doi.org/10.3133/sir20265136

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Abstract

Lake Huron, one of the five Great Lakes, borders the United States and Canada, with Michigan as the only U.S. State on its shoreline. Like other freshwater lakes, it faces water-quality challenges from nutrients and chemicals applied across its drainage basin. Although past studies focused on surface-water sources, groundwater contributions remain less understood. To address this gap, the U.S. Geological Survey, as part of the Cooperative Science and Monitoring Initiative, classified drainage basins to Lake Huron into eight hydrogeologic zones based on bedrock rock type and glacial sediment transmissivity. Utilizing existing data and empirical field data, we quantified groundwater discharge and identified areas of concern for loading of chloride and nitrate to Lake Huron. Groundwater contributions, including indirect and shoreline discharge, ranged from 5.8 to 11.5 inches annually, totaling 1.9 cubic miles and 0.09 cubic mile, respectively. Hydrogeologic zones with higher glacial sediment transmissivity yielded greater indirect groundwater discharge. Chloride levels above the U.S. Environmental Protection Agency’s 250-mg/L recommendation were mainly in the Saginaw lowlands, whereas nitrate above the 10-mg/L standard was rare—found in only 11 wells. Together, the analysis of where groundwater discharge is occurring in the Lake Huron Basin and the identification of areas with potential groundwater-quality concerns can help prioritize areas that are critical to protecting the long-term health of Lake Huron.

Plain Language Summary

Lake Huron is one of the five Great Lakes and is solely bordered by the State of Michigan on the U.S. side of the lake. Nutrients like nitrate and chemicals like chloride are commonly applied to the land surface in the form of agricultural fertilizers and road salts. Nutrients and chemicals can then be transported to downstream water bodies, such as Lake Huron, through streams and groundwater flow. However, neither the volume of groundwater nor the nutrients and chemicals it contributes to Lake Huron are well understood. As part of the Cooperative Science and Monitoring Initiative program, the goals of this study were to assess how much groundwater annually enters Lake Huron and identify if groundwater may be causing nitrate or chloride contamination to Lake Huron. In this study, we quantified groundwater contributions to Lake Huron for drainage areas with similar geology, analyzed existing datasets of groundwater quality with respect to nitrate and chloride, and collected field samples to compare to the other analyses. The results showed that most of the groundwater entering Lake Huron came from groundwater that discharges to streams that flow into the lake, and smaller amounts of groundwater enter Lake Huron through groundwater that directly discharges to the lake shore. Chloride was found to be a greater contaminant risk to Lake Huron because elevated chloride was identified in many groundwater samples from both the bedrock and glacial aquifers. Nitrate was less prevalent in the groundwater samples analyzed. Most groundwater samples did not have detectable levels of nitrate, and the samples that did were primarily from groundwater in the glacial aquifer that lay under agricultural areas.

Suggested Citation

Kaemming, B.B., Ford, C.M., and Martin, S.L., 2026, Assessment of groundwater quantity and quality contributions to Lake Huron: U.S. Geological Survey Scientific Investigations Report 2026–5136, 41 p., https://doi.org/10.3133/sir20265136.

ISSN: 2328-0328 (online)

Table of Contents

  • Acknowledgments
  • Plain Language Summary
  • Abstract
  • Introduction
  • Methods
  • Groundwater Quantity and Quality Contributions to Lake Huron
  • Discussion
  • Summary
  • References Cited
Publication type Report
Publication Subtype USGS Numbered Series
Title Assessment of groundwater quantity and quality contributions to Lake Huron
Series title Scientific Investigations Report
Series number 2026-5136
DOI 10.3133/sir20265136
Publication Date April 20, 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, 41 p.; Data Release
Online Only (Y/N) Y
Additional Online Files (Y/N) N
Additional publication details