Cyanobacteria Prevention and Remediation

New Hampshire's Cyanobacteria Plan: House bill 1066, passed in the 2022 legislative session, directed NHDES to develop a plan to prevent the increase of, and eventually control, cyanobacteria blooms in New Hampshire’s waterbodies. "New Hampshire’s Cyanobacteria Plan: A Statewide Strategy" (Cyanobacteria Plan), published in November 2023, includes input from a 17-member advisory committee and specifies the actions needed to achieve the legislative directive. The plan describes four strategies:

• Strategy 1: Develop policies and practices to reduce, control and prevent the nutrient inputs that cause cyanobacteria blooms.
• Strategy 2: Advance education/outreach efforts.
• Strategy 3: Enhance monitoring.
• Strategy 4: Identify best practices for public drinking water supplies.

NHDES hosted a webinar series following the release of the Cyanobacteria Plan. The recorded presentations cover an overview of the plan, a description of the Cyanobacteria Harmful Algal Bloom (CyanoHAB) program, what individuals can do to prevent excess nutrients from entering their lakes, and the use of overlay districts for additional management. The presentation slides are also available.

Watch the webinars       View the slides  

Homeowner guidance: What can you do?

The best method for decreasing the likelihood of cyanobacteria blooms is to reduce nutrient pollution into the lake. Individuals around a waterbody can take steps to prevent excess nutrients from entering lakes, including:

1. Be aware of the Shoreland Protection Act and its restrictions on the use of fertilizers along the shoreline. 
2. Have your household septic system inspected and pumped at least once every three years. 
3. Pick up after your pets.
4. Maintain a buffer of natural vegetation on the water’s edge.
5. Look at the “Do-it-yourself fact sheets” from Soak Up the Rain NH for advice on inexpensive ways to address stormwater runoff on your property.
6. Participate in NH LAKES’ LakeSmart Program to get recommendations on what you can do to better protect lake health.

A Watershed Management Plan is a useful tool to identify and prioritize projects to address the major sources of nutrient pollution into the lake. Contact Nisa Marks to learn more.

Cyanobacteria Mitigation Fund

The Cyanobacteria Mitigation Fund (CMF) was established by the legislature in 2023 to help defray the costs of implementing nutrient control practices to reduce chronic and extended cyanobacteria blooms. Municipalities, community water systems, and non-profit lake and river watershed associations are eligible to receive CMF assistance. For more information, see Administrative Rule Env-Wq 2300 and the eligibility application.