General Information Located in the North East in Massachusetts The park contains 30,657.78 acres The main island in the park is a long narrow barrier island which protects the great marsh and the 3 rivers behind the barrier island A small island on the western part of the park is home to Josh Mountain the highest peak in Massachusetts
History Founded originally by John Smith The island was originally used by neighboring towns as a pasture for hogs, cattle and horses It became known that the island was home to many birds and also protects the rivers and tidal creeks behind the island. The salt marsh found in thepark was used for insulation,livestock feed and bedding. The island was made anational park in 1920 becausethe importance of the nestingareas for the birds and thedunes protecting the inland.
Geologic History Late in the Quaternary period the Quaternary Ice Age receded and the rising sea level flooded the beach ridges The water as it flowed from the beach ridges to the new coast carried along sediment. The rivers from the mainland also carried sediment helping form the barrier island. Due to the meso tidal coast in the north east the barrier island is transgressive meaning its retreating inland.
Great Marsh The Great Marsh makes up much of the park and is the largest salt marsh in New England. The marsh is directly influenced and dependent on the cycle of the tide, erosion and sediment deposition. The marsh is a transitional zone meaning during high tide most of the marsh is underwater and during low tide much of grass land goes above the water and can be traversed. The marsh is important to the land because it helps preserve many breeding and migratory birds. The marsh supports 67,000 shorebirds representing 30 species. Much of the fish and shellfish consumed relies on the marsh and wetlands for at least apart of their life cycle
Josh Mountain Pink granite formed in the Paleozoic era makes up much of Josh mountain Elevation 1400 feet The mountain has been directly changed due to glaciers coming down into the mountain. The mountain is muchsteeper on the right sidedue to the glaciers andwould be much higherelevation if the glaciersdidn’t cut the tips andmove that sediment downinto the islands to the west.
Recreational Use The long beaches along the barrier island are perfect for family outings and relaxing in the sun The marsh and wetlands which the beach protects when in high tide are perfect for boating adventures given there are miles of unexplored marsh and wildlife Throughout the park the are many observational posts where anyone can walk around and see numerous amounts of different types of birds. The mountain to the west provides for great hiking and sightseeing of the islands and marsh to the east.
Shaping of the Landscape The original shaping of the landscape was primarily due to glaciers. The glaciers helped change the shape and size of Josh mountain and pushed sediment out creating more islands. When the glaciers melted and the sea level rose the sediment was further carried down the coast creating the main barrier island. Now the landscape is primarily influenced from the meso tidal coast. Due to the tides, the sediment is carried inland and during storms the waves reach and go beyond the parks dunes directly changing the structure of the island. The rivers behind the island carry sediment forward into the marsh and barrier island however the coast is taking away sediment faster then the rivers can replenish the sediment.
Human Impact on the Land Humans have made much impact on the marsh land in the park including filling, dredging, extensive ditching, water quality impacts, loss of upland buffers, restricted or blocked tidal flows, obstructed fish passages, channelized and buried coastal streams.