Water Quality Monitoring

Viewing a secchi disk as part of water quality monitoring

The SLA has been collecting water quality data on Squam since 1978 in partnership with the University of New Hampshire’s Lakes Lay Monitoring Program. This volunteer program runs June through August and collects a number of parameters at thirteen sites across the Squam Lakes (sites are marked in the map below). Click Here for a description of the Water Quality Monitor Volunteer position description. 

Once per week volunteers measure water transparency, or clarity, using a secchi disk (see the secchi disk in action in the photo to the left). Though water clarity depths vary throughout the sampling season, secchi disk measurements of over 5 meters generally reflect pristine water quality. Algal blooms and suspended sediments are two factors that can impact water clarity. Every other week volunteers also collect an integrated water sample. The sample is later tested for chlorophyll, phosphorus and color.

Overall, the average summer seasonal water quality testing indicates that the Squam Lakes are well within the limits for a pristine lake. However, certain areas of the lakes are displaying more productive conditions (more algae and weeds) during certain years and some areas are approaching less pristine conditions at a faster rate than natural processes should dictate.

Get Involved!


The SLA's rich history of water quality data on Squam Lake is the result of decades of work of a dedicated group of volunteers. Click Here to contact SLA's Community Engagement Coordinator to participate as a Water Quality Monitor, or to get involved in any of our volunteer programs.

Learn more

Learn more about the Squam through this basic limnology information sheet.

Yearly analysis of water quality in the Squam Lakes in the Squam Watershed Report

2013 Water Quality Reports from UNH

2012 Water Quality Report from UNH

1975 Water Quality study from Harvard University

Water Quality Monitor Position Description

Contact the SLA's Director of Conservation with a question


Map of Squam water monitoring sites