NLC News: Miacomet Pond Opening

Miacomet Pond is one of the most heavily used ponds on Nantucket for recreation including fishing, boating and swimming adjacent to the barrier beach. With a huge contributing watershed relative to its size, it is also an impaired water body that experiences elevated nutrient levels and harmful algae blooms. Over the last decade the water quality research conducted by the Town of Nantucket and the Nantucket Land Council on Miacomet Pond has demonstrated that this pond should be managed as a freshwater system. Unfortunately, someone took matters into their own hands last week and opened the pond to the ocean, likely to alleviate high groundwater levels. This has resulted in a 4 foot drop in the pond’s water level. While some may experience drier basements for a while, it is not likely to bode well for Miacomet Pond.

The Town will be monitoring the impact to the pond throughout the season and the Land Council will provide any assistance that we can. In addition to the potential for a salinity spike which would shock the pond organisms and ecosystem, this extended opening and extreme drawdown is likely to increase nutrient inputs from the surrounding watershed, leave shallow mucky areas ripe for mosquito larvae, facilitate the spread of invasive species, and could also increase phosphorus release from within the bottom sediments exacerbating harmful algae blooms this summer.