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Water Quality Testing


The Gilford Islands Association has been supporting the Lake Winnipesaukee Association’s water quality monitoring program on Sanders Bay and the Broads since 2010, both with volunteers and financial assistance.  Volunteers monitor five sampling stations in total, collecting water samples from May through September on a biweekly to monthly basis.

Keeping Lake Winnipesaukee clean and healthy depends on monitoring the water quality at numerous locations throughout the year.  The Lake Winnipesaukee Association (LWA) assists the UNH Cooperative Extension’s Lakes Lay Monitoring Program (UNH LLMP) on Lake Winnipesaukee. There are approximately 25 to 30 sampling stations on the lake that rely on volunteers to collect water samples on a regular basis throughout the summer.  The water samples are analyzed at the UNH laboratory in Durham, producing a meaningful set of data from year to year, which are also used to monitor the long term health of the lake.

The Lake Winnipesaukee Association supports the water quality monitoring program on Winnipesaukee by helping to recruit, train, and coordinate the transportation of samples to the UNH lab.  As the program is volunteer based, we rely on active participation of lake residents, and the financial support of the local lake, homeowner, road association and conservation commissions to ensure the program’s success.

It takes approximately 1 to 1 ½ hrs. per site to conduct the measurements.  Volunteers measure water clarity through the use of a secchi disk and view scope, take lake temperature readings every 0.5 meter to determine the thermocline (transition zone between the upper warm and lower cold layers), and collect water samples for later lab analysis for total phosphorus and chlorophyll-a concentrations.  Phosphorus is a nutrient required for plant growth. Increased levels of phosphorus in the lake may lead to more algal blooms and plant vegetation in the lake. Chlorophyll-a is a measure of the microscopic plant abundance or ‘greenness’ in the water.  In general, the more plants and algae in the water, the less clear the water will be.


If this seems like a worthwhile endeavor, then  you too can volunteer to help with water monitoring of the lake. Click here to find the LWA volunteer form.  Fill out the form, print it, and send it to the address on the form. Or you can send it to the Gilford Islands Association, c/o Heidi Kephart, 296 Old Lakeshore Rd., Gilford, NH 03249.

To access a map of the sampling locations and to view the water quality data, visit







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Robin Folsom, Round Island, is looking through the viewscope to measure water clarity on Sanders Bay.  Ken Cody, a Meredith resident, joined the training.

Bob Craycraft, UNH Lakes Lay Monitoring Program, is demonstrating how the water sample gets filtered, while Robin and Ken observe.

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