The sand, the water and the storms

How people built Coney Island's beach, what storms and pollution have done to it, how the city tests the water, and what wildlife comes ashore.

The beach and Parachute Jump from Steeplechase Pier, October 2023 · Giorgio Galeotti · CC BY-SA 4.0

People added sand to Coney Island Beach to make it wider. A NYC Parks sign says the project that began in 1921 used 1.7 million cubic yards of sand and added 2.5 million square feet of beach. Since then, crews have added more sand and built stone groins. A groin is a rock wall built out into the water to hold sand.

The story of the amusement parks is on the main Coney Island Beach page.

How did people build the beach?

People added sand to widen Coney Island Beach. The city got title to the beachfront in 1921 and then built the beach out to hold the crowds. A NYC Parks sign says the project used 1.7 million cubic yards of sand and added 2.5 million square feet of beach. The sign puts the beach work and boardwalk at $3 million. Wikipedia puts the boardwalk and related improvement projects at $20 million. The two figures come from different sources, and we could not reconcile them.

By 1937 the beach was shrinking. In a recorded speech at the New York Aquarium, Parks Commissioner Robert Moses said that when the city took over Coney Island in 1937, it had only about 50 acres of shrinking, crowded beach. “Often at high tide there was no beach at all,” he said. Between 1938 and 1941 Parks widened the beach again and covered it with a 2-foot layer of fine white sand.

At the west end, stone holds the sand. The Parks beach ends at a stone groin at West 37th Street, next to the gated community of Sea Gate. Sand west of that groin, out to Norton Point, was washing away fast, and water threatened to cut around the groin's end. In January 2015 the Army Corps of Engineers was working on a $25.2 million federal contract to fix this. It called for four new T-shaped stone groins, an extra arm on the West 37th Street groin, a stronger stone wall at Norton Point and about 100,000 tons of stone. The plan also called for about 125,000 cubic yards of sand. A 2023 report says the Corps built the four groins in 2016 and placed 75,000 cubic yards of sand around them. The first sand figure is what was planned; the second is what was placed.

What did Hurricane Sandy do to the beach?

Hurricane Sandy stripped 600,000 cubic yards of sand off Coney Island Beach in October 2012, according to Marine Technology Reporter. The storm surge pushed sand and water up and over the boardwalk.

In 2013 the Army Corps put about 580,000 cubic yards of sand back. The goal was to return the beach to the shape the Corps had designed for it.

These numbers measure different things. The 600,000 is sand the storm took away. The 580,000 is sand the Corps placed afterward.

The Army Corps says the raised beach limited damage behind it. It estimates that the beach avoided about $494 million in damage to houses and other structures during Sandy. That is the Corps' own estimate, as quoted by Marine Technology Reporter.

Not all of the flooding came from the ocean. Local activist Craig Hammerman told City Limits in 2023: “It was [the] creek flooding over that really hit the community the hardest during Sandy, it wasn't the ocean as much.” In early 2023 the Coney Island History Project said storm erosion at Neptune Avenue and West 21st Street had gone unrepaired for 10 years. “During a king tide the water level in the creek is higher than the street,” it wrote.

Why did the city replace parts of the boardwalk with concrete and plastic?

The boardwalk was built of wood. After a long public fight, the city approved replacing parts of it with concrete and recycled plastic in 2012.

In 2010 Parks proposed rebuilding the whole 2.7-mile boardwalk in concrete and plastic lumber, except a four-block historic stretch from West 15th to West 10th Streets. In May 2011 Parks narrowed the planned concrete lane from 16 feet to 12. Friends of the Boardwalk collected more than 1,000 signatures against concrete.

The city gave cost and durability as reasons. Parks said its tests showed concrete was more durable than faux wood and not slippery. On cost, in 2011 it said plain concrete cost $90 a square foot, against $114 for concrete topped with plastic lumber. In 2012 Parks said $90 was about $40 a square foot cheaper than real wood. The two comparisons use different baselines and should not be combined. Parks designer Alex Hart said, “We would greatly prefer to use wood,” but the city had found none that worked. Black locust was rejected on cost.

On March 12, 2012, the city's Public Design Commission voted 6-0 to let Parks replace the wood between Coney Island Avenue and Brighton 15th Street. The design had a 12-foot concrete lane for emergency vehicles, with 19-foot paths of recycled plastic boards on each side. More than 40 people spoke against it at a four-hour hearing.

By November 2014 Parks was about to start a $10 million phase with a 10-foot concrete lane. A spokesperson said it fit the de Blasio administration's policy of using less tropical hardwood. Residents sued, lost and appealed. Ida Sanoff said a concrete stretch already felt different: “You feel it, just as you walk you feel the difference in your legs.” That is as of 2014. Our newest source on the surface is from that year, so we could not confirm which sections are wood, concrete or plastic today.

What is wrong with Coney Island Creek?

Coney Island Creek, behind the neighborhood, is badly polluted. As of November 2023, it was not a federal Superfund site. The creek began as the Jamaica Ditch, dug in 1750, and was filled in stages until 1962 left it an inlet.

In 2016 the city found 16 apartment buildings in Gravesend dumping 200,000 gallons of raw sewage a day into the creek, possibly for years. Rain and sewage also flow in from a sewer pipe that carries both, between the Stillwell Avenue and Cropsey Avenue bridges.

An EPA site inspection in December 2021 found cyanide and large amounts of mirex, a banned ant poison. That added to earlier findings of PCBs, lead and benzene. Local activist Ida Sanoff has said the creek holds dangerously high levels of lead, mercury and pesticides from decades of factory dumping.

Here is the timeline. In December 2020 an EPA email said the creek qualified for an on-site investigation. In November 2023 the EPA's site manager told City Limits: “Currently, the site is being reviewed by the state programs.” As of November 2023, the state did not list a water body unless it was first a federal Superfund site. We found no decision on the creek from 2024 to 2026.

A 2020 Brooklyn Paper report said many locals swim, fish and hold religious ceremonies at Kaiser Park on the creek, which environmentalists say risks long-term harm. A $15 million plan for bioswales (planted ditches that soak up rain) on Mermaid Avenue, funded after Sandy in 2014, was never built. The reason given was “our water table was too high,” City Limits reported.

What are the flood plans, and where do they stand?

One major flood plan that includes Coney Island is an Army Corps of Engineers draft called the New York-New Jersey Harbor and Tributaries plan, released September 26, 2022. In our newest source, from February 2023, it was still a draft. The Coney Island History Project called the $52 billion plan a shocker for Coney Island.

On the ocean side, the boardwalk would be raised five feet, with what appears to be a wide concrete walkway acting as a surge barrier. Historian Charles Denson wrote that the barrier “would block ocean views for boardwalk businesses as well as taking up about a third of the boardwalk.”

On the creek side, the plan calls for a mechanical tide gate across Coney Island Creek, from Neptune Avenue to Calvert Vaux Park. Sea walls and flood walls would run along Kaiser Park and Coney Island Creek Park, then curve around Sea Gate to the boardwalk at West 37th Street.

The Corps called its drawings initial concepts that may change. The comment deadline was moved from January 6 to March 31, 2023. A 2022 History Project post said the plan would be final in two years, with construction starting in 2030. The Corps only sends the plan to Congress, which must approve the money. We found no source on its status after early 2023.

The water is rising either way. Sea level around New York City has risen about a foot since 1900. In 2024 the city's climate panel projected one to two more feet by the 2050s.

How does the city test the water?

In 2026 the city Health Department tested the water at Coney Island every week during beach season. Sampling started one month before the season opened.

The test counts enterococci. These bacteria usually do not make people sick by themselves. They are a warning sign of fecal pollution, which can carry more dangerous germs. A Northwell Health doctor said the most common problem from swallowing dirty water is a stomach illness.

New York State sets the limit for a single sample at 104 enterococci per 100 milliliters of water. On July 6, 2026, after heavy rain, the Coney Island sample measured 227. ABC7 said the usual level there is near 20. On July 9, ABC7 reported the city warned people to stay out of the water at a dozen beaches. Fox Weather counted 18 locations under advisory.

A yellow sign means an advisory: swimming and wading are not recommended. A red sign means a closure: they are not allowed. Rain alone can trigger an advisory when it passes a beach's set limit. During an advisory the beach stays open, so you can still walk and sit on the sand.

If you think you got sick after swimming, the Health Department says to see a doctor and call 311. We could not find the exact rain amount that triggers an advisory, or how many advisories Coney Island had in 2025.

What wildlife comes to the beach?

Horseshoe crabs come ashore on Coney Island Beach every May and June, NYC Parks says. They prefer to breed at night on high tides, within a few days of the full or new moon. One female can lay more than 100,000 eggs in a season. The eggs hatch in two to four weeks.

If a crab is stuck on its back, Parks says: “It's ok to flip them back - just don't pick them up by the tail!” A broken tail will not grow back. The IUCN lists horseshoe crabs as vulnerable, threatened by habitat loss, pollution, and harvesting for medical blood tests and bait.

Parks' horseshoe crab page lists Brooklyn viewing spots at Plumb Beach, Gerritsen Beach, Kaiser Park and Calvert Vaux Park, but not Coney Island Beach. At Calvert Vaux, on Coney Island Creek, a sandy beach was designed in 2011 as spawning habitat. At the Coney Island Creek Natural Area, on Bay View Avenue, migrating birds eat crab eggs and can double or even triple their body weight before moving on.

Two NYC Parks pages give different ages for the species. The Parks horseshoe crab page says horseshoe crabs have been around for more than 300 million years. The Parks Coney Island Creek Natural Area page says roughly 1.2 billion years. We could not check either against a science source, so we do not pick one.

We found no reliable record of seals, piping plovers or other wildlife seen on Coney Island Beach itself.

Sources

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