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State Issues a Cyanobacteria Advisory for Spofford Lake

September 10, 2020 Advisory

NH DES posted an advisory for Spofford Lake due to the presence of Cyanobacteria.

The adivsory says the following:

"Surface blooms can rapidly change and accumulate in various locations around a waterbody. Please continue to monitor your individual shorelines for changing conditions. NHDES advises lake users to avoid contact with the water in areas experiencing elevated cyanobacteria cell conditions, also known as a bloom. NHDES also advises pet owners to keep their pets out of any waters that have a cyanobacteria bloom."

Click Here for the DES Advisory.

September 11, 2020 Update

  • DES has confirmed that the black organic matter that washed up on two beach areas this past week is a cyanobacteria called 'Lynbya'
  • Lyngbya can form mats either on the surface or as benthic (bottom) sediments which are usually dark blue or black.
  • According to DES, Lyngbya appearing in NH is rare and that it recently appeared on Lake Winnpesaukee and Spofford Lake is unique. It's a new situation for DES
  • Lyngbya is slow growing. It's likely been on the lake bottom for sometime. We don't know why it rose to the surface to be pushed by the wind and waves to these beach properties.
  • Phosphorus levels at Spofford Lake's deep spot are acceptable: about the same as other lakes in the region. But phosphorus, coupled with the Lake's low dissolved oxygen and the summer's much warmer water may have accelerated algae growth.
  • According to NOAA, the average temperature in NH this summer was the 2nd warmest since 1960.
  • Phosphorus sources we can control come from run-off, septic systems and waterfowl.
  • There aren't any quick or easy remedies here. This is a unique situation which DES will study extensively before permitting the use of chemicals, raking, vacuuming or harvesting, even if any of these are practical.
  • Advice quoted from Amanda McQuaid, PhD of DES' 'Harmful Algal and Cyanobacteria Bloom Program:

"There are still many things to learn here. These (Lyngbya blooms) can be toxic...these can target the digestive system and cause nervous system failure if consumed. People should be on alert and be looking before they enter the water. I think where it is clear, it would be fine .Keep pets out of this black sludge and be careful if handling it. If people are raking it, it should be disposed of as a hazardous material. I would not leave it out for animals to get to it. It is best to leave it alone and let it die. Please... call me at 848-8094 for questions"

Let the SLA know if you find other deposits of what appears to be lyngbya 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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