April 6th 2021  By Walt Hessler

Ongoing Water Quality Monitoring at Loon Lake

It is important to monitor the quality of the water that enters Loon Lake.  Monitoring provides the objective evidence necessary to make sound decisions on managing Loon Lake’s water quality today and in the future.  Water-quality monitoring is used to alert us to any potential problems and to determine how to address any problems that may be detected.

You cannot tell much about the quality of water simply by looking at it; most pollutants are invisible to our eyes.  Nutrients are the primary cause of water pollution. The primary pollutants in this category are nitrogen and phosphorus. This type of pollution has impaired more than 3.8 million acres of lakes, ponds, and reservoirs nationwide.  Excess nutrients cause algae to grow out of control and use all the available oxygen in water, killing off other organisms that need oxygen to live.

The most effect method for identifying these harmful nutrients is to conduct testing of the water entering a body of water like Loon Lake.  The Watershed Foundation (TWF) conducts monthly testing on the Winters ditch which is the largest tributary supplying water into Loon Lake.  Watershed Foundation Baseline Water Quality Assessment consists of monthly water chemistry sample collection.  Sampling occurs regardless of flow and weather conditions from February to October.  The 2021 monitoring season will be the 11th consecutive sampling year.  Two sample bottles are filled for analysis of:

map of area around loon lake and the snap shot data showing green levels around loon lake

  • Nitrate-nitrogen
  • Total phosphorus
  • coli.
  • Flow
  • Dissolved oxygen
  • Water temperature
  • Conductivity
  • Turbidity (water clarity)
  • pH

 The data collected are compared to a set of water quality targets and compared to previous years and baseline standards. 

TWF also annually conducts a Snapshot Monitoring day in which the same types of data are collected from a total of four tributaries feeding into Loon Lake.  This is part of over two hundred citizen scientists joined forces to collect, test and analyze water samples from across our locality.  All the data collected is again compared to previous years data and baseline standards.  All the information is mapped and made available on the TWF website ( Snapshot Monitoring Day will be held on September 23rd this year.  You do not need any prior training or experience to participate!

Secchi Disk DiagramIn addition to all this testing there is a color and clarity test done in Loon Lake twice a week from Memorial Day weekend through Labor Day using a Secchi disc.  This data is provided to Indiana University “Clean Lakes”.  

The Loon Lake Property Owners Association (LLPOA) has requested and been granted a complete Water Monitoring Kit from the Indiana Department of Environmental Management’s Hoosier Riverwatch.  The goal is to expand the monthly Loon Lake water monitoring done by TWF.  The first target will be the outlet on the north end of Loon Lake.  This will provide additional information on the quality of the water in Loon Lake.  This new testing will start in April.   

It is especially important that the work done by TWF and the LLPOA help protect and ensure the health of Loon Lake and the quality of the water feeding into our lake.  The purpose of water monitoring is to:

  • Produce water quality data needed to understand and protect our watersheds and aquatic resources.
  • Become aware of water quality issues and aquatic resources and engaged in effective watershed stewardship, especially pollution prevention.
  • Help to identify problem areas that need further investigation and reduce the risk of water quality degradation.

The goal of this article is to raise awareness about water issues and to inform the Loon Lake residence of the important efforts being made to protect and improve Loon Lake’s water quality.  It takes volunteers and support to accomplish all the water monitoring discussed in this article.  Both the LLPOA and TWF are always in need of volunteers.  You can contact TWF at or you can contact the LLPOA at to volunteer.

Join our email list.

Stay up to date with the happenings at Loon Lake!  Email us your name and we’ll add you to our regular email blasts.