Great Ponds

Hummock Pond
Hummock Pond is a eutrophic coastal pond located on the southwest side of Nantucket Island. Hummock is approximately 2.3 miles long, running north to south with an average depth of 6 feet. The watershed to pond ratio, at an average is 15 to 1. The pond is approximately 142 acres in size with a surface drainage basin of approximately 2,227 acres and a groundwater drainage basin of approximately 2,000 acres. Hummock Pond is opened 2 times a year to enhance marine fisheries.
Map of Sampling Stations | Annual Reports

Long Pond
Madaket Harbor and Long Pond make up a unique ecosystem encompassing approximately 9 square miles. These 2 systems are hydrologically connected via Hither Creek and the Madaket Ditch. Long Pond is somewhat isolated from the whole system, and may be evaluated as having separate water quality issues. It is relatively narrow and winding with depths of 4 to 6 feet with no deep basins.
Map of Sampling Stations | Annual Reports

Miacomet Pond
Miacomet Pond is located on the south side of the island of Nantucket. Miacomet Pond has a surface area of 46 acres. There is a maximum depth of 11 feet near its southern end and the mean depth of the pond is 4.8 feet. The pond has a large surface water drainage area of approximately 1,284 acres based on the topography of the surrounding landscape. The probable area of groundwater drainage to Miacomet Pond is 1,047 acres.
Map of Sampling Stations | Annual Reports

Sesachacha Pond
Sesachacha Pond is a coastal eutrophic salt pond located on the northeast portion of Nantucket Island. It is a kettle pond with 2 deep basins of 15 to 18 feet on the northern and southern end. The surface area of the pond is approximately 266 acres with a drainage basin of 800 acres. Sesachacha Pond is opened 2 times a year to enhance marine fisheries.
Map of Sampling Stations | Annual Reports

2008 & 2009 Reports
Due to lack of funding annual reports from 2008 and 2009 are not available. State required testing for shellfish and public beaches were preformed by the Massachusetts Department of Environmental Protection and the Massachusetts Division of Marine Fisheries.

A history of water quality is available online. Reports on list that are not found online are available by request.