Our Work
Water Quality
Protecting the water quality of Lake Monomonac is the primary mission of the Monomonac Lake Property Owners Association. Clean, healthy water is essential for recreation, wildlife, and the long-term health of the lake. The MLPOA works on several fronts to protect the lake, including water quality and monitoring (VLAP), prevention and management of milfoil and other invasive species, cyanobacteria monitoring, and tracking road salt usage, as well as other initiatives. As an important next step in protecting the lake, we are now implementing the lake’s Watershed Management Plan (WMP). Together, these efforts help identify potential threats and guide actions to protect Lake Monomonac.
Monitoring the Lake
Monitoring plays an important role in protecting Lake Monomonac. MLPOA tracks a variety of conditions that affect the lake’s health, including overall water quality, cyanobacteria activity, the presence of milfoil and other invasive species, and the methods of road salt use within the watershed. These monitoring efforts measure indicators such as water clarity, nutrient levels, and algae activity to help track the condition of the lake over time. Together, this information provides a clearer picture of how the lake is changing and helps identify potential concerns.
Understanding the Results
The information gathered through these monitoring activities helps guide lake management decisions and supports implementation of the Watershed Management Plan. By tracking environmental conditions, the MLPOA and its partners can better understand how factors such as nutrient levels, watershed activity, invasive species, and road salt use influence the lake. This information helps focus lake protection efforts where they will have the greatest impact and supports long-term stewardship of Lake Monomonac.
Protecting the Lake Together
Water quality protection depends on the actions of everyone who lives around and enjoys the lake. Responsible shoreline management, proper septic system maintenance, and preventing the introduction of invasive species all play a role in keeping Lake Monomonac clean and healthy.
Top Ten List of things YOU can do to improve Lake Monomonac water quality
- Don’t use phosphorus fertilizers. Use organic fertilizers or none at all. Because our lake is acidic, it is actually good to use lime.
- Update failing or failed septic systems. Several new technologies exist that are ideal for small lots close to the water. See www.thecleansolution.com for more information on a new type of system.
- Use indoor bathrooms. Schedule water activities before meals so people are less likely to have to use the lake as a restroom, especially small children. Do not bathe yourself or your pets in the lake water with soap and shampoo.
- Do not feed the ducks or geese. They do not need it, and their waste is bad for the water.
- Plant vegetation on or near the shore to prevent run off into the lake. See www.NativePlantList.pdf for a guide to plant selection.
- Use biodegradable dish and laundry detergents that do not contain phosphates.
- In the winter, use de-icers that do not contain salt.
- Prevent fuel leaks from aging motors and fueling equipment. Do not store any fuel, cleaning supplies, batteries, etc near the water.
- Choose non-toxic building materials for docks and rafts. Pressure-treated lumber, railroad ties, telephone poles, and similar materials are harmful to the lake and illegal to place in the water. Use cedar, aluminum, plastic and other approved composite materials.
- Communicate and Educate. Help family members, neighbors, and guests understand the importance of protecting the lake. Encourage them to follow responsible lake practices and share these tips with them so everyone can do their part.
Lake Host Program
The Lake Host Program was created by the NH Legislature in 2000 to minimize the introduction and spread of invasive aquatic plants and animals in NH lakes.
Lake hosts are present at the boat ramp at North of the Border on Rt 202 to perform courtesy inspections on boats and trailers entering and leaving the lake. These inspections are intended to detect invasive species before they can be transferred into a water body; once established, invasive aquatic animals and plants can quickly and profoundly change the character of a lake and can be difficult and costly to remediate. Financial support for the program comes from various places: MLPOA, WSLA, individuals and state grants managed by NH Lakes.
Water Testing—Volunteer Lake Assessment Program (VLAP)
The New Hampshire VLAP is one of the oldest programs in the state for the protection and preservation of lakes. It was launched in 1985 to establish a citizen-based lake sampling program to assist NHDES in evaluating lake quality throughout the state and to empower citizens with information about the health of the state’s lakes and ponds. This cooperative effort allows state biologists and lake associations to make educated decisions regarding the condition of their lakes.
MLPOA volunteers collect water samples at various locations around the lake each June, July, and August. These sample are sent to NHDES, which analyzes and interprets the data and provides an annual water quality report specific to our lake.
Cyanobacteria
Questions and answers about Cyanobacteria (Click to view PDF.)
Cyanobacteria (formerly known as blue-green algae) are naturally occurring in most lakes, though often in relatively low concentrations. Many species of cyanobacteria grow in colonies that form surface-water “blooms.” Blooms consist of thousands of individual cells and are diverse in appearance, ranging from green, blue-green, yellow, white or black. Research indicates that cyanobacteria concentrations increase as lake nutrients increase.
In 2024, Lake Monomonac, as well as many other nearby lakes, experienced an increase in reported blooms. This increase may be attributed to the use of fertilizers containing phosphorus. Frequent blooms not only represent a health hazard, they impair recreational use of the lake and depress property values.
See a bloom? Contact MLPOA with details: date, time, and lake location. Alternatively report to NHDES through the NHDES Website Bloom Report Form or by scanning the QR code below. NHDES will sample the site to determine if cyanobacteria are present. If concentrations are elevated, it will issue a lake warning (advisory), continue to monitor the affected area until the bloom has cleared and update the appropriate parties. It is advised that if you or your pet comes in contact with cyanobacteria, you rinse off with fresh water as soon as possible.
Invasive Eurasian Water Milfoil
MLPOA works with NHDES to control the invasive Eurasian water milfoil on the lake. Each spring and early fall (if time allows) NHDES surveys our lake and maps where they find milfoil. At present we control the milfoil on the lake with the use of divers harvesting the milfoil. We contract with divers recommended by NHDES. We have a grant agreement with NHDES for costs. (In 2025 it was a 50% grant.) We have treated specific areas of the lake chemically in the past and are now using divers to manually remove the smaller less dense plants that exist today. Today, only smaller/less dense areas exist.
The red dots on the 2025 lake map (right) identify milfoil areas which were removed by divers. We are pleased we can once again make the NH side of the lake milfoil-free. See the full report (PDF).
John Sarasin Lake Education Day
2026: Another successful Lake Ed Day for the books!
Thirty Rindge Memorial School 5th grade students joined NHDES Limnologists on 8 pontoon boats to study hands-on methods for water testing. When scheduling this event last fall, MLPOA learned there was lack of funding for transportation. It was an easy vote for the board to pay for the bus as this annual event is a wonderful way to further our mission to “educate the community about lake stewardship”.
We thank: Rindge Acres Beach Association (RABA) for graciously allowing us to use their beach for launching the boats; the 8 captains for taking the students out for the two hours on the water; the NHDES limnologists for sharing their knowledge and teaching the kids; MLPOA board member Laureen Moran for managing this event to run smoothly each year; and of course the kids who brought such curiosity—it was wonderful to see how engaged and interested they were.
History: Established in 1969, this joint effort with NHDES was initially titled Lake Ecology Day. In 2005, it was renamed in honor of its founder, John Sarasin. John wanted to impress upon young people the importance of vigilance in protecting lake health. Each spring, fifth grade students from Rindge and Winchendon join NHDES limnologists on pontoon boats supplied and captained by MLPOA members for a day of hands-on water tests that are designed to reflect the health of the lake. NHDES tells us that we are the only lake in NH holding a Lake Education Day!
