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NH DES changes its Cyanobacteria Advisory to 'Alert' Status
for Spofford Lake

On October 7, members of the SLA and the Town of Chesterfield met with Amanda McQuaid, PhD with the NH DES harmful Algal and Cyanobacteria Bloom Program, to inspect for a second time areas around the lake where cyanobacteria have come ashore. 

According to McQuaid, the sites have improved as the mats have begun to disperse, the overall volume has lessened, and the odor is less obvious. She viewed these as all positive signs.  Based on these observations, NH DES downgraded the situation at Spofford Lake from an “Advisory” to an “Alert.”

Current recommendations are:

  • Handle any debris on beaches with care, burying it away from the water where it will naturally degrade,  
  • Clean watercraft in the same manner as suggested for invasive species, like milfoil, which is to thoroughly wash the boat away from the lake,  
  • No human or animal consumption of lake water,
  • Do not use lake water to shower,
  • Keep pets away from the shoreline as they are often drawn to the odor emitted from the mats and may roll in them, and
  • Occasionally eating fish from the lake (no heads or organs) shouldn't be a problem

McQuaid is reasonably sure that the cyanobacteria mats have been present in Spofford Lake undetected for years.  She suspects, but cannot confirm, that due of a combination of factors, e.g., warm and lower water, lake agitation, nutrient rich sediment, and ample sunlight, mats dislodged and came ashore.  Cyanobacteria floating in the water does not pose a major danger as the concentration of the bacteria is low.  Rather it is the high density of the bacteria in the mats that is potentially problematic.

In late September, the SLA contracted with Green Water Labs in Florida to analyze the bacteria.  Results have confirmed the presence of Scytonema, Tolypothrix , and Stigonema, the latter of which has also been found in Lake Winnipesaukee.  Previously, the species was thought to be the more dangerous, Lyngba wollei.  In the meantime, DES will run additional tests and is collaborating with  Keene State College which will  perform DNA tests.

When questioned about the likely situation in the Spring, McQuaid believes that wind, rain, and ice will cause the current mats to degrade and disappear, but that she could not rule out that another bloom or more mats would not appear in 2021.   Downstream areas, e.g., Partridge Brook, are likely to follow the same pattern of activity as Spofford Lake.

Click here to read the 10/7/2020 DES Alert

For more information, see the Cyanobacteria page under the 'Stewardship' tab. Or contact Dr. McQuaid at 603-848-8094. 

Let the SLA know if you find other deposits of what appears to be cyanobacteria  around the Lake.

You can email us at info@spoffordlakeassociation.org or via facebook


To protect, enhance and sustain the ecological, environmental and recreational character of Spofford Lake and the surrounding watershed.

The Spofford Lake Association is a registered 501(c)(3) non-profit organization.

Spofford Lake is a 739-acre (2.99 km2) water body located in Cheshire County in southwestern New Hampshire, in the town of Chesterfield. Water from Spofford Lake flows via Partridge Brook to the Connecticut River. The village of Spofford is located at the lake's outlet.



Donations fund our projects "to protect, enhance and sustain the ecological, environmental, and recreational character of Spofford Lake and the surrounding watershed". These include the Core Sediment Analysis Project, the Solitude Lake Mgt Inspection, the Lake Host program, Water Quality Testing, and the Weed Watch program.

In 2019, the SLA's 238 members donated $37,703 toward the cost of these programs.



View or Print the Spofford Lake Association Spring 2020 newsletter here. All that's missing is your donation envelope.

A copy was mailed the first week of July.

If you have questions, comments, gripes or compliments, please send us an email via the Contact Us.


Spofford Lake Resource Information

Everyone enjoys Spofford Lake. It's a jewel and remains such thanks, in part, to state regulations enforced by a number of NH agencies.

We have compiled a short listing of state departments you can contact concerning frequently asked questions for:


Spofford Lake Association
PO Box 177
Spofford NH, 03462 USA



The Spofford Lake Association is a registered 501(c)(3) non-profit organization.

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