GOFFSTOWN - Namaske Lake in the Pindardville area of Goffstown has become the worst case of milfoil infestation in New Hampshire, a state official told the board of selectmen Monday night.

About half of the 194-acre Namaske Lake is coated with milfoil, which is an aggressive aquatic weed native to the United States, but not New England, according to Amy Smagula, a limnologist and exotic species program coordinator for the Department of Environmental Services.

Smagula said the milfoil, which generally is found in shallower areas, has grown to the maximum extent possible in the lake, which exists where the Piscataquog River backs up to the Kelley Falls Dam. Part of the lake, which is owned by the state, borders properties in Manchester.

Milfoil grows 10 to 15 feet tall, rising to the surface in Namaske Lake. It can clog the engines of motor boats and makes it dangerous to swim because it is so thick. In other states, people have drowned in milfoil-infested waters. “Picture like a corn crop under water, more or less,” Smagula said. “It’s literally an aquatic jungle.”

2007 map of milfoil on Namaske Lake

Milfoil also can harm aquatic life by blocking out the sunlight and depriving the water of oxygen, causing fish to suffocate.

Michael Allard, who has lived by Namaske Lake all 45 years of his life, said he first noticed the milfoil in July 2006 and contacted the state immediately. Smagula said the state had to focus on eradicating an infestation in Scobie Pond, which is upstream in Francestown. Otherwise, efforts downstream would have been futile, she said.

Last month, Allard formed the Namaske Lake Association to tackle the milfoil problem. The association has been working on an application for a state grant for a herbicide treatment of the milfoil early next summer. Smagula estimated it would cost between $50,000 and $90,000. The state, she said, could afford to pay for half.

After that, the town would have to follow up with smaller-scale anti-milfoil activities every three to five years. “You are not going to ever be milfoil free in that lake at this point because there’s always going to be a little bit of persistent milfoil within the Piscataquog River system,” Smagula told selectmen.

Smagula also has been talking with officials in Manchester about sharing some of the cost, since the city has properties on the lake. There are 150 homes on Namaske, according to Allard.

Selectman Vivian Blondeau questioned how she could justify spending taxpayer money on a private lake. Smagula responded that it is a public body of water owned by the state.

“We can assure you, it is used very much by the public and by very many people in the town of Goffstown,” Allard said.

Right now, the only public access ramp to the lake is on Electric Street near the West Side Arena in Manchester. Blondeau said she knew people who had tried to use it had been harassed and had their tires slashed. Selectman Scott Gross said the town could build its own public access ramp on land it owns off Cove or Bay streets.

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