LACONIA — Infestations of milfoil at Pickerel Cove and Moulton (or Chattle) Cove at the northwest end of Paugus Bay will be treated with a chemical herbicide this summer, but a proposal to treat colonies in other parts of the bay was shelved for fear it would adversely effect the municipal water supply .
Dean Anson, who chairs the Conservation Commission, said that earlier this year Amy Smagula, who heads the exotic species program at the New Hampshire Department of Environmental Services (DES) recommended treating infestations of milfoil around the shore of the bay with the chemical herbicide 2,4-D. He said that he, together with Seth Nuttelman, superintendent of the Laconia Water Works, and Planning Director Shanna Saunders, met with Smagula to assess the impact of the herbicide on the city's water intake near the foot of the bay.
Anson said they requested information about the flow of water in the bay only to learn that charting the flows would require a very expensive study.
Anson said after reviewing the information about 2,4-D, particularly its risks to human health, the Conservation Commission, Planning Department and Water Works, agreed to limit the application of 2,4-D to Pickerel Cove and Moulton Cove and not pursue Smagula's proposal to treat other areas of the bay with the herbicide.
Nuttelman said that the department questioned the recommendation to treat colonies of milfoil beyond the two coves and closer to the intake pipe. He said that the DES acknowledged that there was insufficient data to ensure that water quality would not be impaired by applying herbicides over a wider area of the bay.
Nuttleman explained that the two coves are three miles from the intake pipe, which is located off shore from the headquarters of the Water Works on Union Avenue in Lakeport. A steady current carries water from Lake Winnipesaukee through Paugus Bay, which turns over relatively quickly. But, water lingers longer in the protected coves. Nuttelman said that calculations indicated that the herbicides applied in the two coves would be sufficiently diluted to pose no risk to the quality of the city's drinking water.
Aquatic Control Technology of Sutton, Massachusetts, a firm that has worked in the city and region for a number of years , including on Lake Opechee last year, will undertake the treatment. Restrictions on swimming and using water from the treated areas will be posted, but Nuttelman stressed that there will be no restrictions on the use of city water.
Anson said that the Conservation Commission will convene a sub-committee of some of its members and other interested parties to address the issue of milfoil. He said that Suzanne Perley, who for a number of years, has managed the effort to control milfoil in Lake Opechee, would serve on the sub-committee.
Perley said yesterday that since Lake Opechee is downstream of Paugus Bay, the investment in treating and managing milfoil there is compromised by milfoil reaching the lake from Paugus Bay.
Anson said that a primary task of the sub-committee will be to develop a plan for managing milfoil in Paugus Bay, which will include mapping and monitoring the infestations and applying appropriate measures to eradicate or control them without posing unreasonable risks to the quality of the municipal water supply.
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