Photo: Water Resources Intern Forest Holbrook takes water samples while veteran water quality monitoring volunteer Steve O’Bryan looks on.
Article by Forest Holbrook
As Coastal Rivers’ Water Resources Intern this summer, my main role is monitoring water quality in local lakes, including Pemaquid Pond, Biscay Pond, Muddy/Paradise Pond, Muscongus/Webber Pond, McCurdy Pond, and Clark Cove Pond. I have also been staffing the Beachcombers’ Discovery Center at Pemaquid Beach Park.
Monitoring water quality in our lakes and ponds involves collecting four sets of data: water temperature, dissolved oxygen, water clarity, and phosphorus.
Phosphorus is an essential nutrient in lakes that aquatic plants feed on. However, excessive levels of phosphorus can result in algal blooms, which can make waters unsafe for both lake ecosystems and human activity. To measure levels of phosphorus, we collect water samples from different sites and send them to the Department of Environmental Protection in Augusta for laboratory analysis.
Dissolved oxygen (DO) refers to the amount of oxygen available to aquatic organisms in a given water body. DO is affected by the water’s temperature and clarity. Warmer water or water where algal blooms or other pollutants are present holds less oxygen, and may result in loss of species and biodiversity. We measure DO, along with temperature, at each meter interval from the surface to a depth of ten meters.
A water quality monitoring volunteer measures water clarity using a Secchi disk.
Water clarity is a good indicator of lake health and the presence or lack of pollutants. We measure water clarity using a Secchi disk – a high-contrast black and white disk that is lowered into the water on a string. We record the depth at which the black and white pattern is no longer visible. The Secchi disk was created in 1865 by an Italian scientist named Pietro Angelo Secchi, and the device is still used around the world today.
The health of our lakes and ponds is highly dependent on those who live and play on the water. Lake-side residents, boaters, and swimmers have the greatest influence on lakes’ water quality. Lake monitoring is a community effort, and so is fostering the lakes themselves. You can make a difference on your local lakes by respecting lake-dwelling animals and by taking advantage of courtesy boat inspections for invasive aquatic plants on your boat.
It’s been exciting to learn more about local lakes and ponds over the summer and connect with the locals to learn more about the local efforts of lakeside residents to care for their lakes. While most of the lakes I monitor are in excellent health, it shows when people come together as a community to protect their lake. Muscongus/Webber Pond has the highest and most consistent water clarity of all the lakes I monitor, which is likely due to the efforts of the proactive pond association which meets periodically throughout the summer.
Anyone interested in helping with water quality monitoring is invited to reach out to Coastal Rivers by emailing info@coastalrivers.org.
