Neponset River Estuary
Lynn Ficarra
General Characteristics
From Walter Baker Dam to Dorchester Bay1
7 km long2
25-250 m wide at low tide, up to 1 km at high tide2
Depth ranges from <2-4 m at low tide2
3 m tidal range3
Large portion of water in estuary
exchanged at each tide3
• Surface area 0.88 km2 at low tide,
2.17 km2 at high tide2
• River flow through dam 0.6-3.1 m3/s
Neponset River Estuary1
Tidally dominant2
Probably well-mixed
Vertical salinity
stratification unknown
• Total volume of water in
estuary unknown
• Bottom topography
Salt marsh4
– Was dominated by native Smooth cordgrass (Spartina
alterniflora) and Saltmeadow cordgrass (Spartina patens)
– Now invasive Common reed (Phragmites australis)
Spartina alterniflora
Spartina patens
Phragmites australis
– Past dredging, loss of natives, opportunity for invasives to
move in5
Habitats cont.
• Mud flats2
• Intertidal: 29% non-vegetated2
Habitat cont.
• In 1991, estuary had 311.64 acres of wetlands5
– 25.92 acres of non-vegetated wetland
– 265.67 acres of salt marsh
– 20.05 acres of common reed marsh
• But what about today?
– All remaining salt marshes degraded7
• Sediment characters unknown
• Anadromous fisheries4
– Rainbow smelt
American shad
– Herring
– American shad
• River dams shortened runs4 and pollution lead to declining
fish populations6
• Nursery4
• Hunting grounds4
Rainbow smelt
Residence Time2
• ≤1 day
Nutrient Limitation7
• Nitrogen limited
• A lot of missing data
• Outdated information
• Projects
– Remove dam to improve
fish populations
– Restore salt marshes
• Will eelgrass and oysters help?
Breault R.F. 2011. Concentrations, Loads, and Sources of Polychlorinated
Biphenyls, Neponset River and Neponset River Estuary, Eastern Massachusetts.
U.S. Geological Survey Scientific Investigations Report 2011-5004, 143 p.
Gardner G.B., R.F. Chen, and A. Berry. 2005. High-resolution measurements of
chromophoric dissolved organic matter (CDOM) in the Neponset River Estuary,
Boston Harbor, MA. Marine Chemistry. Vol. 96:137-154.
Zhu J. and C.R. Olsen. 2009. Beryllium-7 atmospheric deposition and sediment
inventories in the Neponset River estuary, Massachusetts, USA. Journal of
Environmental Radioactivity. Vol. 100:192-197.
NepRWA. 2006. Neponset Salt Marsh Restoration. The Neponset River
Watershed Association.
Tiner R.W., D.B. Foulis, C. Nichols, S. Schaller, D. Petersen, K. Andersen, and J.
Swords. 1998. Wetland Status and Recent Trends for the Neponset Watershed,
Massachusetts (1977-1991). U.S. Fish and Wildlife Service National Wetlands
Inventory Project Northeast Region. 32 p.
Massachusetts Government. 1998. Neponset River Subwatershed-River and
Estuary Segment Assessments. Boston Harbor Watershed 1999 Water Quality
Assessment Report. p. 87-188.
NepRWA. 2004. Neponset River Watershed 2004 Assessment Report.
Massachusetts Executive Office of Environmental Affairs. 56 p.

Ficarra Estuary - BIOEEOS660-f12