- > 100 ft
Spit on north side is sparsely populated with summer cottages; 4-wheel drive required to access. South side of marsh also has homes.
The marsh complex is very large and is best accessed by boat or by hiking along Sandy Neck.
- Listed on more than one “valuable wetland” list by natural resource agencies or nongovernment organizations.
- Protects biological diverse wetland flora, fauna and/or their habitat
- Supports significant numbers of wetland-dependent fauna, such as water birds or fish
Great Marsh is an integral part of a barrier spit/embayment complex called Sandy Neck. It is recognized by Massachusetts as an Area of Critical Environmental Concern (ACEC) and as providing "Habitat of Potential Regional or Statewide Importance." This is the study site in which Alfred Redfield proposed how a salt marsh develops by accretion of sediment in his seminal wetlands paper, "Development of a New England Salt Marsh (Redfield 1972)." Thus, this wetland has both biological and historical significance to wetland scientists.
- Aesthetic/cultural heritage value/ provisioning
- Recreation (birdwatching, ecotourism)
- Storm abatement
- Carbon storage
- Water quality improvement
- Coastal Salt Flat
- Coastal Salt Meadow
- Coastal Regularly Flooded Salt Marsh
- Coastal Saline Sound/Bay
- Tidal Systems
Great Marsh is part of Cape Cod, formed at a terminal moraine of the Wisconsin Ice Sheet. It formed when sea level rose reaching glacial deposits and sand spits formed along the shore, which accreted from sediment carried by longshore currents. Great Marsh formed behind sand on the north shore of Cape Cod and deposited peat as it kept pace with sea level change and expanded. Old marsh is underlain by peat, while more recent marsh is forming over sand and between and around erratic boulders.