Water Quality

Keeping the lake in good shape is a major part of what the Elkhart Lake Improvement Association is dedicated to doing.  Each year, ELIA monitors the health of Elkhart Lake by participating in the Wisconsin Citizen Lake Monitoring Network which is supported by the Wisconsin Department of Natural Resources (WDNR) and designed to improve the effectiveness of lake monitoring across the State in order to build and maintain the dynamic picture of our natural resources. Working with the staff at the WDNR, professional marine biologists, and with volunteers to help make “Keep Elkhart Blue” a reality for all to enjoy.

The ELIA Water Quality Committee volunteers monitor Elkhart Lake’s water quality each year including disk data (turbidity), temperature (using a digital meter from surface to 95 ft bls) and dissolved oxygen data up to six times a year. In addition, we collected water chemistry data for phosphorus and chlorophyll three to four times a year. The water chemistry data is collected three or four times a year including the last two weeks of June, July, and August. Observations including ice-on and ice-off, water color, appearance and perception are also recorded as well as spring overturn (or turnover) which happens within two weeks after ice out. This allows us and the WDNR to assess the state of nutrient enrichment in the lakes. Click here for more information about the data ELIA collects.

The analyzed data results are submitted to the WDNR who help manage the extensive database and evaluate the data to prepare annual reports for Elkhart Lake. Elkhart Lake was sampled six different days during the 2019 season. Click here for the detailed 2019 Elkhart Lake Water Quality Annual Report.  The 2019 results continue to be static from previous years and the lake continues to be classified as a Mesotrophic lake.  Trophic status is a useful means of classifying lakes and describing lake processes in terms of the productivity of the system.  Mesotrophic lakes are characterized by clear water with a medium amount of nutrients (Phosphorus and Nitrogen), with an increasing chance of low dissolved oxygen in deep water during the summer (Picture to the left).  These lakes, like Elkhart Lake, are commonly considered healthy with a diverse populations of aquatic plants and algae.  They are also great fishing lakes and are home to many sport fish such as walleye, perch, smallmouth bass, muskellunge and northern pike.

Mesotrophic lakes behave differently than oligotrophic and eutrophic lakes in that they stratify, meaning they separate into layers in the summer. The top layer of water becomes warm from the sun and contains algae. Since the by-product of photosynthesis is oxygen, oxygen concentration remains high at the surface of the lake. The bottom layer remains cooler and can become anoxic in mid-summer. This change occurs because as all the algae and other organisms die and are decomposed at the bottom of the lake, oxygen gets used up.  Since this bottom layer of water does not mix with the top layer of water in the summer, oxygen cannot be replenished. The implications of anoxia are that no fish or other organisms can live where there is no oxygen; therefore, in late summer, fish move shallower where there is still oxygen available.

ELIA has been monitoring Elkhart Lake for many years through grants and volunteer efforts. Refer to the documents section on the Caring for Lake page to access some of these reports and learn about Elkhart Lake. ELIA also participates in the WDNR’s satellite water program. This program originated in 1999 estimates water clarity on approximately 8000 lakes annually across Wisconsin. The WDNR depends on citizen-based monitoring for field measurements needed in satellite calibration. This powerful management tool that helps the agency monitor a large number of lakes in a cost-effective manner (less than $1 a lake). The large database supplied by this effort can assist managers is looking at the “big picture” with respect to Wisconsin’s changing lake conditions, i.e. how are lakes changing in different regions of the state, different lake classes, different size lakes? In the near future, we hope to start examining how lakes are responding to past and future climatic conditions and land use changes.