Dredging of Chilmark Lower Pond on the south shore of Martha’s Vineyard is scheduled to begin this month in the hopes of improving the pond’s water quality. In recent years, the pond has seen summer blooms of toxic cyanobacteria, fueled by excess nutrients (phosphate and nitrogen) in the bottom sediments. It’s hoped that removing up to 6,000 cubic yards of sand from the pond will alleviate the problem and allows better flushing of the water when the pond is opened to ocean each fall.

Obtaining a permit to dredge the pond has been challenging. In 2023, the process was delayed by the U.S. Fish & Wildlife Service over concerns that the dredge spoils might harm the endangered northeastern beach tiger beetle, which live along barrier beaches.

The dredging is part of a multi-pronged approach to build pond resilience. This will include a buoy that uses ultrasonic waves to disrupt the formation of cyanobacteria in the pond.