PUBLICATIONS—Scientific Investigations Report
U.S. Department of the Interior
U.S. Geological Survey
Michigan Water Science Center
In cooperation with the Michigan Department of Environmental Quality
ONLINE ONLY
This report is available below as a 58-page PDF for viewing and printing.
The U.S. Geological Survey and the Michigan Department of Environmental Quality are jointly monitoring selected water-quality constituents of inland lakes through 2015 as part of Michigan’s Lake Water Quality Assessment program. During 2001–2005, 433 lake basins from 364 inland lakes were monitored for baseline water-quality conditions and trophic status. This report summarizes the water-quality characteristics and trophic conditions of those monitored lake basins throughout the State.
Regional variation of water quality in lake basins was examined by grouping on the basis of the five Omernik level III ecoregions within Michigan. Concentrations of most constituents measured were significantly different between ecoregions. Less regional variation of phosphorus concentrations was noted between Northern Lakes and Forests (50) and North Central Hardwoods (51) ecoregions during summer possibly because water samples were collected when lake productivity was high; hence the utilization of the limited amount of phosphorus by algae and macrophytes may have resulted in the more uniform concentrations between these two ecoregions.
Concentrations of common ions (calcium, magnesium, potassium, sodium, chloride, and sulfate) measured in the spring typically were higher in the Michigan southern Lower Peninsula in the Eastern Corn Belt Plains (55), Southern Michigan/Northern Indiana Drift Plains (56), and Huron/Erie Lake Plains (57) ecoregions. Most ions whose concentrations were less than the minimum reporting levels or were nondetectable were from lakes in the Michigan northern Lower Peninsula and the Upper Peninsula in the Northern Lakes and Forests (50) and North Central Hardwoods (51) ecoregions. Chlorophyll a concentrations followed a similar distribution pattern. Measured properties such as pH and specific conductance (indicative of dissolved solids) also showed a regional relation. The lakes with the lowest pH and specific conductance were generally in the western Upper Peninsula (Northern Lakes and Forests (50) ecoregion).
The Michigan Department of Environmental Quality classifies Michigan lakes on the basis of their primary biological productivity or trophic characteristics using the Carlson Trophic State Index. Trophic evaluations based on data collected from 2001 through 2005 indicate 17 percent of the lakes are oligotrophic, 53 percent are mesotrophic, 22 percent are eutrophic, 4 percent are hypereutrophic, and less than 5 percent are classified into transition classes between each major class. Although the distribution of lakes throughout Michigan or between Omernik level III ecoregions is not uniform, about 85 percent of the lakes classified as oligotrophic are in the Northern Lakes and Forests (50) or North Central Hardwoods (51) ecoregions. Nearly 28 percent of all the lakes in each of these two ecoregions were classified as oligotrophic.
Historical trophic-state classes were compared to the current (2001 through 2005) trophic-state classes. Approximately 72 percent of lakes remained in the same trophic-state class, 11 percent moved up a partial or full class (indicating a decrease in water clarity) and 18 percent moved down a partial or full class (indicating an increase in water clarity).
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Whole report (11.2 MB) - 58 pages (8.5” by 11” paper)
Suggested Citation:
Fuller, L.M., and Minnerick, R.J., 2008, State and regional water-quality characteristics and trophic conditions of Michigan’s inland lakes, 2001–2005: U.S. Geological Survey Scientific Investigations Report 2008–5188, 58 p. Date Posted: December 17, 2008: [http://pubs.water.usgs.gov/sir20085188/]
Abstract
Introduction
History of Monitoring on Inland Lakes
Purpose and Scope
Physical Setting
Water-Quality Data-Collection Methods
Lake and Site Selection
Site Identification
Sampling Strategy
Field and Laboratory Methods
Trophic-Status Evaluation
Data Quality Assurance, Treatment of Censored Data, and Data Access
Statewide Water Quality of Inland Lakes
Inland Lake Water Quality and Ecoregions
Specific Conductance and pH
Trophic State Index Class Compared to Maximum Lake Depth and Lake Area
Comparison of Current Trophic Assessment with Historical Assessments
Summary and Conclusions
Acknowledgments
References Cited
Appendix 1. List of Michigan lake basins sampled from 2001 through 2005
Appendix 2. Rationale for treatment of censored data
Appendix 3. Water-quality constituents in Michigan lake basins from 2001 through 2005
Appendix 4. Spatial distribution of water-quality constituents in Michigan lake basins from 2001 through 2005
Appendix 5. A limnologic explanation of water-quality characteristics and constituents sampled in Michigan lakes, 2001–2005
1A–3. Maps showing:
1A. Inland lakes greater than 25 acres in the Lower Peninsula of Michigan.
1B. Inland lakes greater than 25 acres in the Upper Peninsula of Michigan.
2. Watershed-management units and 5-year rotational cycle for Lake Water-Quality Assessment in Michigan.
3. Omernik level III ecoregions for Michigan.
4. Photograph showing a U.S. Geological Survey technician filtering water for chlorophyll a analysis.
5. Photograph showing a Secchi disk, which is lowered into the water attached
to a measuring tape to determine the
Secchi-disk depth.
6. Map showing pH in Michigan lake basins during spring turnover for 2001 through 2005, lain on Omernik level III ecoregions.
7. Map showing specific conductance in Michigan lake basins during spring
turnover for 2001 through 2005, lain on
Omernik level III ecoregions.
8. Graph showing relation of Trophic State Index class to lake depth in Michigan lake basins, 2001–2005.
9. Graph showing relation of Trophic State Index class to lake area in Michigan lake basins, 2001–2005.
1. Properties and constituents of water-quality data collected from Michigan’s lakes sampled 2001–2005.
2. Lake trophic state and classification ranges for Trophic State Index for total phosphorus, Secchi-disk transparency,
and cholorophyll a.
3. Number of Michigan lakes, basins, and lakes with multiple basins sampled from 2001 through 2005.
4. Statistical summary of Michigan lake basins sampled from 2001 through 2005 by season and lake.
5. Statistical summary of Michigan lake basins sampled from 2001 through 2005 by Omernik level III ecoregions.
6. Results of statistical tests comparing constituents between Omernik level III ecoregions.
For additional information, contact:
U.S. Geological Survey
Michigan Water Science Center
6520 Mercantile Way, Suite 5
Lansing, MI 48911-5991
GS-W-MIlns_DC@usgs.gov
or for more information about USGS activities in Michigan, visit the USGS Michigan Water Science Center home page.
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