Groundwater

Sandy and gravelly glacial-outwash plains and deltaic deposits can yield large supplies of water where the saturated thickness exceeds 30 ft. Some areas of high potential well yield occur along Furnace Brook in Marshfield, near Herring Brook in Hanover, and in coastal deposits in Duxbury. Productive sand and gravel also occurs within or beneath unstratified glacial moraines, especially in the southern half of the area. Beach deposits provide small supplies of fresh to brackish water, but commonly have more than 500 mg/L of dissolved solids.

Granitic and altered sedimentary and volcanic rocks provide a secondary aquifer for domestic wells. In 1970, the yield of 133 bedrock wells ranged from a fraction of a gallon per minute to 128 gal/min. The yield of 81 wells was less than 15 gal/min and the yield of eight was more than 60 gal/min; five of the eight wells with higher yields were industrial wells.