In This Issue:

A Splash from the Editor: What to expect in Ripples, and a call for volunteers.

Why Pleasant Lake Needs a Watershed Management Plan

Limnological Lore: Lakes as Sentinels of Climate change

Nurture Natives Nix the Nutrients: Northern Blue Flag Iris and Rhodora

What Samples are Being Taken to Monitor the Health of Pleasant Lake? 

Spotlighting a Lake Steward: Doug Bent

Why Pleasant Lake Needs a Watershed Management Plan

Dave Hollinger, PLPA

We treasure Pleasant Lake for its clean water, recreation, wildlife habitat, and special sense of place that has drawn families to its shores for generations. In recent summers, though, the lake has shown warning signs that we should not ignore. Cyanobacteria blooms have appeared in the water, and they are a signal that the lake's health needs our attention. The encouraging news is that we already know what causes these blooms, and we have proven tools to turn the trend around. A Watershed Management Plan, or WMP, is the most important of those tools.

Cyanobacteria Are on the Rise

Cyanobacteria, sometimes called blue-green algae, can form blooms that look like green paint or pea soup on the water's surface. Some blooms release toxins that are harmful to people and pets. There is no record of cyanobacteria blooms on Pleasant Lake before June of 2022, when the New Hampshire Department of Environmental Services issued a cyanobacteria watch for Pleasant Lake. Localized blooms near Elkins Beach and along Lamson Lane have been reported in June each year since. In 2025 a second, lake-wide bloom appeared in late September. As described elsewhere in this newsletter, PLPA has responded to these changes with weekly cyanobacteria sampling and a real-time monitoring buoy.

Pleasant Lake is not alone. Across New Hampshire, cyanobacteria blooms are becoming more common. The number of bloom advisories rose steadily from 2003 to 2023, and the state now averages over 60 reports of water bodies with cyanobacteria each year. In 2024, New Hampshire issued its earliest bloom advisory ever, on May 15. Scientists link this trend to more nutrients washing into lakes, warmer water, and changing rainfall patterns. Blooms are even appearing in lakes that never had them before and outside the usual late-summer season. These changes make a clear, science-based WMP more valuable than ever.

What a Watershed Management Plan Does

Generally, the key to fewer cyanobacteria blooms is fewer nutrients, particularly phosphorus, but also nitrogen. Nutrients feed cyanobacteria, so the fewer nutrients that reach the lake, the fewer blooms it can support. A Watershed Management Plan (WMP) uses standardized methods from the U.S. Environmental Protection Agency to answer three questions: how much phosphorus is entering the lake; where it is coming from; and, how much it must be reduced to keep the water healthy. To find the sources, experts use detailed shoreline surveys, septic system records, sediment analyses, and computer models of the land around the lake.

The WMP then lists specific actions at specific places. Each action comes with an estimate of how much phosphorus it will remove and how much the removal will cost. That lets the community rank projects by the greatest phosphorus reduction per dollar spent, so money goes where it does the most good. A WMP is scientifically sound, includes education and ongoing water testing, and is required to qualify for most state and federal remediation funding.

Where Phosphorus Comes From: Two Local Examples

Nearby lakes show what a WMP can reveal. The 2020 Lake Sunapee Watershed Management Plan found that about 75% of the phosphorus entering the big lake is carried in runoff, and most of that comes from land that people have developed or altered, such as with roads, lawns, rooftops, and businesses. Other sources of Lake Sunapee phosphorus include septic systems (about 10%), waterfowl (4%), and direct input from rainfall and dust. Armed with this information, Lake Sunapee set a goal to cut phosphorus by 100 kilograms per year, a 7.5 percent reduction over ten years. Meeting this goal should strongly reduce the chances of cyanobacteria blooms.

Messer Pond, also here in New London, tells a similar story. Messer Pond is a 67-acre water body that the state has listed as impaired for high phosphorus and algae. Its plan found a total yearly external phosphorus load of about 51 kilograms. Runoff flowing across the land in the pond's 11 small sub-watersheds, plus stream flow, also make up about three quarters of that load. The rest comes mainly from septic systems and from phosphorus that falls from the air. Knowing these numbers lets each community target its biggest sources first.

Projects That Are Already Working

These plans are not just studies that sit on a shelf. They lead to real projects. In the Lake Sunapee watershed, the Lake Sunapee Protective Association (LSPA) has undertaken dozens of projects. Work has included replacing an undersized culvert with a deep sump catch basin to trap sediment, installing rain gardens, disconnecting roof downspouts, and adding dry wells through the Watershed Wise program. Vegetation is an effective way to stop sediment and nutrients from getting into streams or directly into lakes. As part of the Lake Sunapee WMP, vegetated buffers have been planted at Twin Lake Villa, Bucklin’s Beach at Little Lake Sunapee, and recently along the west shore of Otter Pond (this LSPA project at Otterville Beach, right off Rt. 11, is worth a visit).  The association also partners with the Ausbon Sargent Land Preservation Trust to conserve forestland that naturally keeps nutrients out of the water.

In the Messer Pond watershed, the Messer Pond Protective Association used grant funding to build its implementation plan and then worked with the New London Department of Public Works to fix erosion along County Road, where soil and phosphorus were washing toward the pond. The group also held information sessions to help neighbors become good lake and watershed stewards with their own properties.

A Hopeful Path Forward

Pleasant Lake is following a similar path. A Watershed Management Plan will give all of us a clear, science-based roadmap and open the door to further funding. On May 27^th, the Town of New London, in partnership with PLPA, applied to the New Hampshire Clean Water State Revolving Fund (CWSRF) for $100,000 to produce a Pleasant Lake WMP. This program commonly pays for Watershed Management Plans by offering a low-interest loan and forgiving the principal once the work is complete.  Unfortunately, the process of obtaining funds and then completing a Watershed Management Plan is slow. A funding decision won’t arrive until the fall, and work on the WMP wouldn’t start until next summer. It typically requires 18 months to complete this work. Once a plan is in hand, however, our community can act with confidence, spend wisely, and protect Pleasant Lake for the families, wildlife, and visitors who depend on it. The challenges are real, but so are the solutions, and the time to begin is now. 

Even before we have the detailed guidance of a WMP, there are things we can do. The sooner we take action to reduce phosphorus inputs to Pleasant Lake, the sooner lake water quality is likely to improve. Already new shoreline buffer plantings are going in, septic systems are getting pumped, and other steps are being taken to prevent runoff from entering our lake. This is only the start: we need more people to get involved and take similar action. We don’t want to see blooms like the one in the photo below anymore!

Here’s what you can do right now 

• If you haven’t pumped your septic system in the last 3 years, start by having it pumped and inspected by a qualified firm this year and keep the receipt. New London now requires all property owners with individual sewage disposal systems to have their septic tanks pumped and inspected at least every three (3) years. Aging or under-maintained systems are one of the largest controllable sources of phosphorus to the lake.

• Plant native plants, including trees and shrubs, along the water’s edge if you own shorefront property.

• Pick up and dispose of pet waste. Poop is a rich source of phosphorus. 

• Eliminate the use of fertilizers on your lawn and garden. While phosphorus is often the key nutrient contributing to cyanobacteria blooms, nitrogen is also a culprit in many lakes!

• Let the PLPA know if you have erosion or runoff problems on your property. We can help you find solutions.

For more information, check out the NHLAKES, “Lake Smart” and Lake Sunapee Protective Association “Watershed Wise” Programs. 

Nurture the Natives!  Nix the Nutrients!

Shoreline vegetated buffers are an effective and potentially beautiful way to prevent soil erosion, filter polluted runoff, stabilize banks, and provide essential wildlife habitat. They are the ultimate "ring of protection" for maintaining the health of our lake and watershed, and Pleasant Lake and its tributaries need as many of us who own shoreline and stream bank property as possible to help complete that protective ring.  Best of all, using native plant species to create your buffer eliminates the need for fertilizers, as these plants, which include trees and shrubs, are adapted to, and thrive in, New Hampshire’s soil conditions. It’s a win-win all the way around!

Here we highlight two spectacular species for you to consider, whether you’re planning a vegetated buffer or simply want to go native.  A more comprehensive list of native New Hampshire plant species that do well on the shorelines of lakes and streams can be found here.

What Samples are Being Taken to Monitor the Health of Pleasant Lake? 

when concentrations of a potentially toxic species of cyanobacteria on the Slope ‘n Shore beach exceeded 161,000 cells/ml. (The level considered dangerous to human health is 70,000 cells/ml.) 

In addition to the Volunteer Lake Assessment Program (VLAP) sampling that the PLPA has done for decades, we are monitoring the plankton more closely this year, including both plant plankton (phytoplankton) and animal plankton (zooplankton). Cyanobacteria are considered phytoplankton, as they are bacteria that photosynthesize. We have only spot samples of phytoplankton every few years from the NH DES, and we need more data on where and when the cyanobacteria occur if we are going to effectively reduce the frequency and severity of bloom events.

This year we are sampling for both phytoplankton and zooplankton on a monthly basis, from May through September. These data will let us know how abundant the cyanobacteria and other species of phytoplankton are, and also identify which zooplankton are in the lake. Although cyanobacteria are not their favorite food, zooplankton can consume them and thereby reduce their densities. Zooplankton are also a critical food source for young fish, and thus they serve an important role in lake food webs and fisheries. They also contribute to improving water quality. Sampling zooplankton will help us determine whether the invasive spiny water flea (a type of zooplankton) has invaded our lake, as it has other New Hampshire lakes.

In addition to this monthly plankton sampling, we are sampling weekly for potentially toxic species of cyanobacteria at three locations up and down the center of the lake. If potentially toxic species of cyanobacteria are observed to be abundant, the samples can be tested within just a couple of days for the presence of toxins. We had the toxins analyzed from the June 30, 2026 bloom on Slope ‘n Shore beach, and fortunately toxins were below the level of detection. It is important to note that cyanobacteria often release toxins when they die, so we need to remain vigilant about the potential for future toxicity in all blooms. Any positive results of toxins are posted on the PLPA website and emailed to Ripples subscribers.

The data from the cyanobacteria sampling buoy are already providing valuable information indicating that the cyanobacteria bloom that was observed at Slope ‘n Shore on June 30^th did not extend lake-wide. This is good news, because it suggests that by reducing nutrient inputs from this region of the Pleasant Lake watershed, we can potentially curb the cyanobacteria blooms at this location. This is a case study for how we may be able to mitigate local cyanobacteria blooms in other areas of the lake. The data that we are collecting this year will be integrated into the watershed management plan (see article above) to provide more effective tools to guide our sampling and cyanobacteria mitigation efforts in the future.  

In this issue, we focus on Doug Bent, PLPA Board member, Chair of its VLAP Committee, and volunteer extraordinaire.  Doug’s roots in Pleasant Lake run deep:  he grew up on the lake and now resides full-time with his wife on the property his parents purchased in 1958.  Although his career in consultative sales took him to locations as nearby as Massachusetts, where he lived for twenty-five years, and as far away as Australia, where he spent over two years, and although he recalls with a wry smile “being on a plane most weekends,” Doug held tight to his dream of returning home to Pleasant Lake upon retiring.  He and his wife built their new house on the site of his parents’ original dwelling, and they moved in five or six years ago.

“Some people get attached to a house,” Doug asserts.  “We’re attached to the location – the lake and the people.”  The familiarity of the Pleasant Lake community and its history are deeply personal for Doug and integral to his identity.  They form the backbone of his relationship with the lake. An important part of Doug’s history – the part that determined his education (a degree in microbiology from UNH), career (technical sales with Charles River Labs), and his volunteer efforts today with the PLPA – began when, as a boy, he’d go out sampling area lakes, including Pleasant Lake, with his dad, Don, in a square-ended canoe with a 3Hp Johnson motor. (Don Bent, incidentally, was New London’s Health Officer for over forty years, and he ran a water testing lab.)  So it was inevitable that, upon his settling permanently on Pleasant Lake, Doug would be approached by members of the PLPA Board to participate in the state’s VLAP effort. He accepted enthusiastically and has been spearheading the program ever since.  

“You could say it’s in my blood,” he remarks with a smile.  “It’s something I learned how to do, and I guess you could say I know enough to be dangerous.” Those who know and appreciate Doug’s self-effacing sense of humor realize that his knowledge is anything but dangerous:  it’s what has informed his vested interest in the stewardship of Pleasant Lake and compelled him in his efforts to raise community awareness of growing threats to the health of the lake.  “The people who live on the lake are aware of the issues,” he goes on.  “The people who live on the hill or in the watershed aren’t as aware of the implications.”  Doug has ideas about how residents can sample in their tributaries, and he’s willing to train them in some basic sampling methodologies. “We are all lake stewards,” he declares with a confident nod.

If you see Doug out in his pontoon sampling Pleasant Lake, take a moment to wave and give him the thumbs-up.  It’ll be a small tribute to a man with a big heart and the devotion built upon a lifetime of memories on his beloved Pleasant Lake.

Ripples welcomes your feedback!  Please contact us with your ideas, suggestions, and thoughts at ripples@plpa.net.

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