Together the two groups manage Michigan's oldest citizen lake monitoring program, which began in 1974 and now involves about 250 people. Many of the volunteers are lake residents, and some of them have been in the program since the beginning, according to Pearl Bonnell, who serves as program treasurer and director of operations. Volunteers test more than 100 of Michigan's inland lakes for water clarity, spring and summer phosphorus, and monthly chlorophyll a levels. Some volunteers also identify and map aquatic plants. These factors can lead to increased lake fertility or productivity.
Productivity refers to the amount of plant and animal life that can be produced within a lake.
A primary objective of most lake management plans is to slow down eutrophication by reducing the input of plant nutrients, such as phosphorus, and sediments to the lakes. Analysis of water samples allows volunteers to assess a lake's productivity, or trophic state, on a numerical scale and identify trends. The Cooperative Lakes Monitoring Program provides training for volunteers, workshops, technical support, quality control and laboratory assistance.