Long Island's Dynamic History

The surface of Long Island was formed at the end of the last glacial maximum, or the time of the furthest extent of the ice sheets during the last ice age, around 21,000 years ago. As the ice sheets advanced from the Arctic, they entrained, or carried along, sand, gravel, and other material which was continually supplied to and accumulated at the melting margin of the ice front, similar to a conveyor belt. As the climate warmed, they began to retreat northwardly leaving piles and layers of sediment. The loose gravel and sand carried here as the ice sheets scraped and ground down rock completely cover the bedrock; therefore, no significant rock formations are located on Long Island. Ridges formed by the glacier stretch across the island as a terminal moraine. The Ronkonkoma Moraine forms the backbone through the center of the island. South of this begins the glacial outwash plain along the south shore. During the irregular retreat of the glacier, it left behind a second moraine: the northernmost, named the Harbor Hill Moraine, which runs along the north shore. The glacial history of Long Island explains the difference between the two shorelines, with bluffs and rocky beaches along the Sound and sandy beaches along the Atlantic Ocean. Other glacial features can be found on Long Island, such as Lake Ronkonkoma, which is a kettle lake that formed when ice was buried by sediment, melted, and left a depression that eventually filled with water.  

The melting and retreat of the glacier caused by warming of the climate, led to increased sea level. While the surface of Long Island may have existed 21,000 years ago, the island as we know it was not there; our shorelines have a dynamic history as they have moved drastically along the continental shelf. As more meltwater entered the ocean, sea levels continued to rise, Long Island became an actual island and seawater filling in the low areas eventually gave it the distinctive shaped shoreline that we see today. The story of sea level rise continues as climate change is still shifting Long Island’s shoreline (see  Chapter 4  to learn more about present-day sea level rise). 

At the same time, as rain or snow entered the ground, it saturates the layer of sand and gravel, both of glacial origin or older in underground formations called aquifers. These aquifers are the source of all Long Island’s potable water. Three aquifers exist underneath Long Island:

·        The Upper Glacial Aquifer is closest to the surface, interacts with, and discharges into, the area’s water bodies.

·        The Magothy is the next layer and is where most water is pumped from.

·        Below this, is the Lloyd Aquifer.

Recognizing that Long Island relies on the aquifers for water, municipalities have built recharge basins, or sumps, that collect groundwater. Pollution and contamination to the groundwater is a major concern for Long Island. 

Long Island was first inhabited by 13 Native American Tribes: Canarsie, Rockaway, Matinecock, Merrick, Massapequa, Nissequogue, Secatoag, Setauket, Patchoag, Corchaug, Shinnecock, Manhasset, and Montauk.

Since many lived along the shores, they used canoes as transportation and relied on fishing. Additionally, they were exceptional farmers and hunters. Each tribe had their own chief, but there was an alliance between all the territories. 

You can learn more about Long Island’s Native Lands  here .

In 1609, Henry Hudson may have landed at what is now known as Coney Island and in 1655 European settlers purchased the first land of Long Island from the indigenous peoples. They continued to search for, purchase, and settle more land while living peacefully with the tribes. Eventually many of the tribes began to move away and those that stayed behind died of smallpox. Disagreements sometimes leading to violence occurred and many tribes were often forced to leave their lands. The first settlements on Long Island were Southampton and Southold in 1640, followed Hempstead, East Hampton, Huntington, Brookhaven, and Smithtown in 1665. In 1645, the Dutch began settling what is now Brooklyn. By 1683, all of Long Island became part of the Province of New York and the three counties, Kings, Queens, and Suffolk, were established.

During the Revolutionary War, the island was captured during the Battle of Long Island, and remained under British and Loyalist control until 1783. In the 1800s, the island remained mostly rural and the land predominantly used for agriculture. By 1844, what is now the Long Island Railroad was completed and in 1883, the Brooklyn Bridge was completed, opening up transportation to Long Island by means other than boats. As more bridges and tunnels were built, residential suburbs began to form in areas where commuting to New York City would be easy. As a result, from the late 19th century through 1930 the population of the island doubled every twenty years. Near the end of the 19th century, wealthy industrialists began to build large estates along the North Shore of Nassau County. The area eventually earned the nickname of the Gold Coast. During the 20th century, Long Island became a center of aviation, with many notable flights originating here, the opening of the first major airport, and the establishment of major Air Force bases and military aircraft production. Through the 1940s, many farms and woodlands gave way to developed suburbs, and after World War II, the population greatly increased, shaping Long Island into what it is today.  

In New York State, the boundary between the publicly owned and privately owned land is the high water mark, or the location of the water at high tide. Land that is below this is considered public and governed by the state. Owners of land adjacent to water have littoral rights. However, since many towns on Long Island were established before the sovereign State of New York, their borders and jurisdictions were created through land grants. These grants conveyed ownership of the land, the water, and submerged lands, meaning many Towns have ownership of bays and bay bottoms within their boundaries. This ownership and control continues today. When sediment accretion occurs, the new land belongs to the owner of the upland; however, if erosion occurs, the land lost returns to the ownership of NY State.   

As the chair of the Long Island State Parks Commission, Robert Moses created parkways over public transit which greatly assisted in the development of suburbs in the area. Multiple parks were linked by various parkways, which is still in use on Long Island today. An example is Ocean Parkway, which connects Robert Moses and Jones Beach State Parks. This plan allowed for easy access to parks, but led to a stabilization of the coastline as infrastructure was built. 

As the population of Long Island grew, so did the demand for access to recreational beaches and an increase in development along the shoreline. Many areas began as, and still are today, getaways for the New York City residents, local populations, and others. As the need for more property increased, much of the Sound and other bays were dredged for fill, which was placed in marshes to create land. In 1972, the U.S. government enacted the “Clean Water Act” which regulated discharges of pollutants into the water, including dredged and fill material. In 1973, NY State adopted the Tidal Wetland Regulations, which mapped, defined, and protected the remaining marshes and required a property owner to obtain a permit before conducting work within 300 feet of the wetland boundary. Many of the waterways are maintained as navigable channels and need to be regularly dredged. Furthermore, beaches along the south shore are routinely nourished, either by the US Army Corps of Engineers as part of the Fire Island to Montauk Point (FIMP) project, or through private, special erosion control districts, in order to maintain them (see more about beach nourishment in  Chapter 3 ). Development along the shorelines has impacted the natural coastal processes and habitats and now many communities and organizations are working to restore the natural landscape.