OUR GEM: The role of Bay Watchers in monitoring Lake Coeur d'Alene

Lake Coeur d’Alene faces numerous environmental challenges that require ongoing vigilance. One of the key programs in safeguarding the water quality of this lake is the Bay Watchers program. 

A collaboration between the Idaho Water Resources Research Institute, the Coeur d’Alene Tribe, Idaho Department of Environmental Quality and local volunteers, Bay Watchers embodies the spirit of citizen science by engaging residents in water quality monitoring, which provides valuable data and fosters environmental stewardship among lake and bay communities. 

Citizen science refers to research conducted by the public, who participate in the scientific process. This has gained popularity as it allows individuals to contribute to scientific understanding and environmental conservation. Bay Watchers exemplify this model by involving residents in the monitoring of Lake Coeur d'Alene. The program’s primary goal is to educate residents through active participation, creating a network of “neighbors helping neighbors” to protect the lake's health. 

The Bay Watchers program empowers volunteers with the tools and knowledge to monitor water quality. 

The monitoring efforts of Bay Watchers focus on two main objectives: educating the public and tracking long-term water quality trends. While the program's educational component encourages residents to share their equipment and findings with neighbors, the scientific component aims to gather data that can reveal changes in the lake’s ecosystem over time. 

Volunteers collect data on various parameters using specific methods: 

Temperature: Temperature loggers are suspended from docks to continually record water temperatures throughout the summer. This data helps identify thermal stratification, where warmer surface waters are separated from cooler, deeper waters that occur during the summer months. 

Water Clarity: Water clarity is measured using a Secchi disk — a black and white patterned disk lowered into the water until it is no longer visible. The depth at which the disk disappears provides a measure of water clarity, which is a key indicator of the lake’s trophic state. 

Dissolved Oxygen, pH and Specific Conductivity: These parameters are measured monthly using a YSI ProPlus multiprobe, which is lowered through the water column at 1-meter depth increments. Dissolved oxygen levels are particularly important as they reflect the lake's ability to support aquatic life. Anoxic conditions, which occur when oxygen is depleted, can lead to severe ecological consequences. 

A critical aspect of the program is monitoring for signs of eutrophication — a process where excessive nutrients, such as phosphorus, lead to increased algae production. When algae die and decompose, the oxygen in the water is consumed, creating anoxic conditions that can harm aquatic life. The oligotrophic state of Lake Coeur d'Alene, with its low nutrient levels, is desirable for maintaining water quality. However, monitoring efforts must be vigilant to detect any shifts towards eutrophic conditions. 

Seasonal changes in lake stratification also play a significant role in water quality. During summer, thermal stratification prevents oxygen-rich surface waters from mixing with deeper layers, which can exacerbate oxygen depletion in the lower depths. In contrast, mixing occurs in spring and fall when temperature changes and runoff allows for the redistribution of oxygen throughout the water column. 

The 2024 season has already seen three months of sampling across 11 bays surrounding Lake Coeur d'Alene. The final sampling in September will be followed by a comprehensive data report, which will be presented at the annual Bay Watchers meeting that is open to all interested in learning more about the program. 

The National Academy of Sciences has highlighted the need for enhanced monitoring efforts in Lake Coeur d'Alene’s bays, where early signs of nutrient enrichment and algal growth are likely to appear. By expanding and fortifying these efforts, Bay Watchers can continue to play a role in protecting the lake’s water quality for future generations. The program exemplifies the power of citizen science in contributing to environmental conservation and fostering a sense of responsibility among local communities. 

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The Our Gem Coeur d’Alene Lake Collaborative is a team of committed and passionate professionals working to preserve lake health and protect water quality by promoting community awareness of local water resources through education, outreach, and stewardship. Our Gem includes local experts from the University of Idaho — Idaho Water Resources Research Institute, Coeur d’Alene Tribe, Idaho Department of Environmental Quality, the Basin Environmental Improvement Project Commission and Kootenai Environmental Alliance.