Northeast Coastal Areas Study
Significant Coastal Habitats
Site 32 (RI)
I. SITE NAME: Hundred Acre Cove/Palmer River Complex
II. LOCATION: Northeast head of Narragansett Bay near the Rhode Island-Massachusetts boundary and the confluence of the Barrington, Palmer and Warren Rivers.
TOWNS: Barrington, East Providence, Swansea,
COUNTIES: Bristol, Providence
STATE: Rhode Island
USGS 7.5 MIN QUADS: Bristol, RI-Mass 41071-63; East Providence, RI-Mass 41071-73
USGS 30x60 MIN QUAD: Providence 41071-E1
III. GENERAL BOUNDARY: The southern boundary of the complex begins at the confluence of the Barrington and Palmer Rivers and extends to the west up the Barrington River to include Barrington Cove and adjacent marshlands to the Running River, near the Barrington, RI/Swansea, MA boundary line, and east up the Palmer River and adjoining marshes upstream to where the river markedly narrows, approximately 1 mile (2 km) north of the RI/MA boundary. The salt marsh and Nockum Hill at Hundred Acre Cove lies between the head of the cove and the Barrington, RI/Swansea, MA line. Extending from this marsh is a long peninsula of salt marsh, the "Tongue", which separates Hundred Acre Cove proper from the Barrington River.
IV. OWNERSHIP/PROTECTED STATUS: Both areas (Hundred Acre Cove and Palmer River Marshes) have a mixed and complicated ownership pattern, consisting of public waters, State/Town lands, private lands (commercial and residential) and private conservation lands (Audubon Society of Rhode Island, Barrington Land Conservation Trust). Nockum Hill is owned and managed by the Town of Barrington.
V. GENERAL HABITAT DESCRIPTION: The major habitat types in this complex are high quality tidal saltmarshes dominated by cordgrasses (Spartina alterniflora and S. patens) with large permanent non-tidal ponds, extensive mud flats and sandy uplands at Hundred Acre Cove, and salt marshes, tidal flats, emergent marsh, shrub thickets and forested swamp associated with the Palmer River.
VI. SIGNIFICANCE/UNIQUENESS OF AREA: Perhaps the most significant feature of this complex is the extraordinary concentration of nesting Northern diamondback terrapin (Malaclemys t. terrapin) that occurs at Nockum Hill in Hundred Acre Cove. This is the only known Rhode Island nesting occurrence of this species whose northern range extends only to Wellfleet, Massachusetts. It is estimated that 50 or more nesting terrapins use the Nockum Hill site to lay their eggs in early summer, a remarkable congregation of this species in this region. The marshes of Hundred Acre Cove also support important breeding populations of clapper rail (Rallus longirostris), seaside sparrow (Ammodramus maritima), and long-billed marsh wren (Cistothorus palustris). A colony of common tern (Sterna hirundo) historically nested on "The Tongue" in this same area. The salt marsh here is the third largest salt marsh estuary in Rhode Island.
A major feature of these marshes is the presence of four large permanent non-tidal ponds. Three of the ponds are on the Tongue, the fourth is on the mainland and is unique due to the presence of a wide band of salt marsh cordgrass (Spartina alterniflora) which surrounds the pond. More than 56 bird species have been observed using the marshes for feeding and resting during migration. Nesting species of special emphasis in addition to those previously mentioned include Canada goose (Branta canadensis), mallard (Anas platyrhynchos), and American black duck (Anas rubripes). Fish species using this river and cove system include white perch (Morone americana), striped bass (Morone saxatilis) and herring. The Palmer River marshes are of high quality and are largely unditched. They provide important nesting habitat for seaside sparrow.
VII. THREATS: Human-related disturbances at the upland terrapin nesting site at Nockum Hill are of considerable concern, as this breeding population is regionally significant. This species is extremely vulnerable to disturbances even from relatively passive recreational activities. Collection and predation threats to terrapins have been reported. The heavy recreational use of the complex as a whole is potentially a very serious threat to the fish and wildlife populations of this area. Chemical contamination in the river from commercial and industrial sources and dumping of household waste impacts the area's water quality. There is the potential for development of the upland periphery of the wetland.
VIII. CONSERVATION CONSIDERATIONS: Protection of the Hundred Acre Cove waters, marshlands and adjacent sandy uplands at Nockum Hill needs to be given high priority and should involve cooperative management and conservation agreements among the State and Town governments and private conservation organizations such as the Audubon Society of Rhode Island, The Nature Conservancy and The Barrington Land Conservation Trust. Improvement and protection of water quality in this river and cove complex should also be given a major emphasis, including strict enforcement of water quality regulations and development and implementation of restoration programs
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