2007 National Lake Survey - Wisconsin Results
Marl Lake, Waupaca County
DNR Photo
In the summer of 2007, Wisconsin's lakes got a checkup as part of a national study to assess the percentage of lakes in good, fair, or poor condition. The EPA-sponsored 2007 National Lake Survey examined ecological, water quality, and recreational indicators for lakes across the country. This site explains the purpose of the survey and what researchers in Wisconsin measured. You can also view the data for each visited lake as they become available.
National Survey Draft Report. New!
What was the Survey's purpose?
How were lakes picked?
Which Wisconsin lakes were visited?
What did researchers measure?
What additional work did we do here in Wisconsin?
What’s next?
What was the Survey's Purpose?
The purpose of the Survey was to assess the percentage of lakes throughout the country in good, fair, or poor condition with regards to water quality, ecological integrity, and recreational value. Researchers also looked at the relative importance of key stressors such as nutrients, non-native species, lakeshore development, and pathogens on lake conditions.An additional goal was to establish a sound baseline to compare future surveys in lake health over time. Last, the EPA’s approach was designed to strengthen state, tribal, and interstate monitoring programs by encouraging more efficient use of resources, expanding accessibility and use of data, and promoting partnerships.
How were lakes picked?
A total of 909 lakes (map), representing five size classes and distributed relatively evenly across the lower 48 states were included in the survey. The lakes were selected randomly (excluding the Great Lakes) from a sample that included freshwater lakes (natural and man-made) and ponds and reservoirs that were at least one meter deep and over 10 acres in size. Also included were lakes sampled in 1972 as part of the National Eutrophication Survey.
Which Wisconsin lakes were visited?
Of Wisconsin’s 15,081 lakes, only 29 were visited as part of the National Lake Assessment (map). They ranged in size from the 11-acre Buckskin Lake in Florence County to the 133,404-acre Lake Winnebago. Two of the lakes, Blueberry Lake in Sawyer County and Haskell Lake in Vilas County, ware located within tribal jurisdictions.
What did researchers measure?
In Wisconsin, a team of Wisconsin Department of Natural Resources (WDNR) and U.S. Geological Survey (USGS) staff sampled the selected lakes throughout July and August of 2007. Samples collected included standard water quality constituents (nutrients, pH, color, chlorophyll-a), water clarity, physical profiles, phytoplankton and zooplankton, a sediment core, algal toxins, pathogens, and benthos (lake-bottom organisms). In addition, a comprehensive shoreline assessment was conducted at 10 sites around each lake. These core indicators will be examined to diagnose the lake’s water quality, ecological integrity, and recreational value.What additional work did we do here in Wisconsin?
In addition to the standard protocol, in Wisconsin we also performed several enhancements:
Aquatic plant surveys: Using funds from the National Lake Survey, most of the randomly selected lakes were sampled for their aquatic plant community using the point-intercept sampling approach. The data will tell us about the maximum rooting depth, distribution of aquatic invasives, and the diversity of the plant community.
Enhanced physical habitat assessment: An additional habitat survey was conducted on expanded shoreland plots to provide more detail on woody debris for fish habitat, invasive species specific to Wisconsin, and to better document the presence and density of human development.
Surface water mercury sampling: As part of an Upper Midwest mercury study conducted by the USGS, National Lake Survey sampling crews for Wisconsin, Illinois, Minnesota, and Michigan collected water samples for total and methyl mercury from approximately 200 lakes. The data will be used to better understand how internal mercury loading rates and ecosystem factors such as water quality, hydrology, and food web characteristics control the magnitude of mercury levels in fish.
What's next?
All sampling in Wisconsin was conducted during the summer of 2007. The EPA released a draft report Dec. 18, 2009, now available to the public for review and comment. As part of an ongoing study, another Survey of the Nation's Lakes will be conducted in 5 years in 2012 or 2013 on another set of randomly selected lakes.
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