Article Published by the Union Leader: DERRY — When Rob Tompkins finishes transforming his waterfront property on Beaver Lake, his 100-foot natural barrier against runoff and erosion will be a paradise of plants: day lilies, blueberry bushes, beech plums, a Japanese maple tree — plus other species with less familiar names, such as sweet pepper bush, Joe Pye weed and nannyberry.
It’s intended to be a working, eye-pleasing boundary between his backyard and the lake, a resource that Tompkins and waterfront neighbors want to keep healthy and clean.
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Like most lakes around New Hampshire, Beaver Lake is under assault from the pavement and lawns that ring it, conveying runoff from fertilizer, a threat that is typically ignored.
“I want my property to be more lake-responsible,” said Tompkins, who has lived here for 37 years. “This year I’m totally natural. It starts with one person. As a lakefront property owner, you have your responsibility to keep the lake healthy.”
The 137-acre, crescent-shaped Beaver Lake is 2 miles from the center of Derry. It’s 46 feet deep at its deepest point and is surrounded by approximately 125 homes — most of which are year-round, with carefully manicured and fertilized lawns.
But green beauty belies a problem. About 90% of lake pollution in New Hampshire is caused by runoff, said Erin Mastine, outreach program coordinator for NH Lakes, a nonprofit focused on lake and water quality.
Fertilized lawns plus paved and impervious surfaces such as driveways, patios and decks can be sluices for pollutants that change the mineral balance and ecosystem of water bodies. That can lead to toxic bacteria blooms.
“When we have a rainstorm, it washes everything in that green lawn right into the lake,” Mastine said.
NH Lakes has been named a 2023 Champion in Action by Citizens and the New Hampshire Union Leader. The recognition, a Citizens initiative for 20 years, comes with a $35,000 unrestricted grant and significant promotional and volunteer support to increase public awareness.
LakeSmart, a free guidance and education program from NH Lakes, hopes to keep the balance tipped toward healthy by helping homeowners — especially those who live near ponds, rivers and lakes — reduce their runoff.
“I’ve always had an amazing lawn,” said Tompkins, a longtime board member of NH Lakes. “People equate trophy lawns with value in their property. But a lawn is not a great thing for a lake. A lawn is not a good buffer.” Tompkins surveyed his personal domain of grass. “I have too much lawn.”
That’s an uncomfortable realization for homeowners who live on or near the water, where backyard beauty is a winner.
Increasingly threatened by erosion and runoff, ponds, rivers and lakes across the Granite State are imperiled by the pollution and the high phosphorus and chloride levels that change the chemical composition of the water. That encourages invasive species and undermines local plants and animals.
New Hampshire’s 1,000-plus lakes are among the cleanest in the country. But they’re under mounting pressure from development and human activity.
During the past three summers, New Hampshire’s lakes experienced a record number of toxic bacteria blooms. Last summer, 47 public health advisories were issued for 37 lakes and one river, according to NH Lakes. In the weeks leading up to the official start of summer, the state’s ponds and lakes already have had more toxic blooms than they experienced by this time last year.
“One of the only ways we can stop these blooms from making us sick, ruining our vacations, lowering our property values and weakening our economy is to help property owners take simple actions to reduce the amount of polluted runoff water flowing off the landscape,” said Andrea La-Moreaux, president of NH Lakes.
For Tompkins and waterfront property owners, the solution includes shifting from a picture-perfect “trophy” lawn to one that is environmentally responsible and nonpolluting.
This year, Tompkins stopped fertilizing his lawn. Instead, he seeded clover and sweet woodruff, ground cover that doesn’t need fertilizer and is the same color as grass. He is extending a 20-foot natural barrier of native shrubs, plants and flowers across the remaining 80 feet of his shoreline. And he is hoping his efforts will gain traction with other waterfront dwellers.
“I want to be the person on Beaver Lake who starts the trend,” Tompkins said. “I didn’t fertilize for the first time in 40 years. Now I have a green lawn. It’s just not all grass. My biggest goal right now is to reduce the amount of lawn I have.”
Fertilizer, road salt, pet waste and leaks from adjacent septic systems raise phosphorous and chloride levels and can lead to algae blooms such as cyanobacteria, which harm people, pets and wildlife who may touch or swallow the water near a toxic overgrowth.
Cyanobacteria pose little threat in their normally low concentrations. The danger comes from dense clusters or blooms that can be triggered by rising temperatures, spells of hot weather and droughts followed by heavy rain, which carries runoff into lake water.
”Our lakes are fragile, and some of them are getting sick,” LaMoreaux said. “If everyone does a couple of things to reduce their contribution to collective pollution, it’s going to make a big difference.”
Natural barriers, including hedges and vegetation, have decreased over time, making runoff an ongoing hazard. Shifting weather patterns don’t help.
In New Hampshire lakes, milfoil, an invasive plant, remains the biggest invader. The Asian clam, which disrupts lake ecology and the food chain, is spreading, according to NH Lakes. Responsible actions by individual property owners become valuable weapons in the freshwater preservation cause.
“We get people to reframe their idea of a green lawn,” said Gloria Norcross, a conservation program leader for LakeSmart, which furnishes recommendations for residential properties, including for driveways and parking areas, lawns, septic systems and shorelines.
LakeSmart’s advice includes a menu of recommended native, erosion-controlling plants and voluntary property modifications that may include digging a trench and filling it with gravel to collect and divert runoff.
Trees, often removed by property owners who don’t understand their role in preserving water quality, provide a root lattice to hold soil in place. Trees close to the water’s edge not only inhibit erosion, they help lower water temperatures, which supports long-term lake health.
“A lot of people don’t know when they move to a lake that some of the well-meaning things they do are unintentionally harmful to a lake,” Norcross said.
LakeSmart, started in 2019, last year provided 470 property self-assessments online and 180 on-site visits to homeowners. The process starts with a 15-minute self-assessment survey at lakesmart.nhlakes.org, followed by a written report.
After property updates are made, waterfront homeowners can request a free visit from a LakeSmart evaluator.
“When you move to a lake, you’re not given a manual,” Tompkins said.