The Basics

The Five Mile Island, more commonly known as “The Wildwoods,” is a barrier island situated at the southern end of New Jersey’s barrier island chain. Stretching from north to south, it encompasses the City of North Wildwood, the City of Wildwood, the Borough of West Wildwood, the Borough of Wildwood Crest, and parts of Lower Township. Together, these five municipalities make up the Wildwoods, a densely developed coastal region (Fig. 1).

The island’s coastline is characterized by sandy beaches, with only minor traces of silt. For example, North Wildwood’s sands are predominantly fine-grained quartz, averaging about 0.2 mm in diameter—a characteristic consistent across the entire island (Corps, 2014).

In terms of topography, the island is mostly flat with a gentle slope toward the west. Notable man-made dunes were added to parts of North Wildwood’s shoreline in 2009 to protect against erosion. These dunes are high and well-maintained, but similar features are absent in Wildwood and West Wildwood (Fig. 2). Further south, Wildwood Crest and Lower Township feature natural dunes of lower elevation along their shorelines. The most expansive and pronounced dune system on the island can be found south of Lower Township at a federally managed Coast Guard training base. These dunes, marked by significant ridges and troughs, are a critical natural feature of the region (Corps, 2014).

The Wildwoods also experience a dynamic coastal climate. During the fall, winter, and spring, northeasterly winds dominate, shaping the meteorological coastal zone. In summer, the heating of land and sea leads to prevailing southeast winds, though the northeast wind remains the overall dominant force year-round. Coastal storms, or nor’easters, are common from October through April but can occasionally occur outside this period (Ludlam, 1983).

This unique combination of sandy shores, man-made and natural dunes, and seasonal weather patterns makes the Wildwoods a fascinating study of coastal dynamics and development.

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Tides

Five Mile Island, like the surrounding southern New Jersey coastline, experiences two high and two low tides each day (a semidiurnal tidal cycle) with small tidal changes. It is bordered by two inlets: Hereford Inlet to the north and Cape May Inlet to the south. Both inlets have structures built to keep them stable, which may affect how tides move inland, though this hasn’t been thoroughly studied.

The main tidal forces come from the moon’s gravity (M2 and N2), with some influence from the sun (S2) and Earth’s rotation (K1). Moving south along the coast, the difference between high and low tides generally increases, likely due to the influence of Delaware Bay. For instance, the tidal range at Stone Harbor is slightly less than at Wildwood Crest, with Cape May having the highest range. Over the last 5,000 years, the tidal range has decreased by about 0.8 feet.

Although data for the tidal volume at Cape May Inlet is unavailable, Hereford Inlet can hold a vast amount of water during high tide, with its “spring tidal prism” holding over a billion cubic feet of water. Historically, Hereford Inlet was one of the widest in New Jersey, but it has narrowed as sand from Stone Harbor moved southward. This narrowing may affect inland tidal flows, though further study is needed.

Tidal flooding is a growing problem on Five Mile Island due to rising sea levels. Floods are becoming more frequent and severe, as reflected in tide gauge data from Stone Harbor.

Waves

The waves around the Wildwoods, also known as Five Mile Island, usually reach an average height of 2.8 feet, with a wave period of 4.2 seconds. Long-period waves, such as those lasting 16 seconds or more, are incredibly rare, with less than a 0.01% chance of occurring annually. In January, waves are highest, averaging 3.9 feet, while in July, they drop to their lowest at 2.33 feet. During calm weather, waves stay below 2.0 feet.

Big storm waves, defined as those over 10 feet high, happen only about 1.3% of the time (Miller, 2022). The tallest wave ever recorded in the area was an impressive 27 feet during Winter Storm Jonas on January 23, 2016. This record-breaking wave, measured at buoy 44009, remains the largest since data collection began in 1984 (Dohner, 2016; NOAA, 2024).

Waves change direction and size with the seasons. In winter, they come from the northeast and are bigger and more powerful. In summer, they shift to the southeast and are smaller and gentler.

The shoreline of the Wildwoods is mostly shaped by sandbars (CRC, 2022). In Wildwood, Wildwood Crest, and Lower Township, offshore sandbars break up larger waves before they reach the shore. The waves lose energy as they pass through a trough and then break closer to the beach. In North Wildwood, however, waves roll in without much interference, leading to smoother but more direct wave breaking on the beach.

This combination of seasonal wave patterns and natural sandbars helps shape the unique beaches of the Wildwoods.

Sediment Dynamics

In southern New Jersey, sand moves southward along the coastline toward Cape May due to the combined effects of currents, wind, and waves. This process, known as longshore drift, leads to the erosion of sand from beaches such as Stone Harbor and Avalon, with the sediment accumulating in Hereford Inlet.

Hereford Inlet plays a significant role in sediment dynamics. Waves and tidal currents shape the accumulated sand into large offshore features known as ebb shoals. Periodically, the inlet releases these shoals, depositing them onto the North Wildwood shoreline in a process called a depositional episode, causing the shoreline to expand temporarily.

After deposition in North Wildwood, sediment gradually migrates southward toward Wildwood and Wildwood Crest. Movement halts at the southern tip of the island due to a stone jetty near Cape May, which acts as a barrier to sand transport. This jetty effectively traps sediment in the Wildwoods, resulting in the unusually wide beaches observed in the area.

Sand deposition and erosion have been analyzed across several shoreline cells, as shown below (rounded to the nearest 100,000 cubic yards):

• Cell 1 (2nd Ave to 10th Ave): -1,400,000 cubic yards
• Cell 2 (10th Ave to 18th Ave): +600,000 cubic yards
• Cell 3 (18th Ave to 26th Ave): +1,400,000 cubic yards
• Cell 4 (Baker Ave to 26th Ave): +4,800,000 cubic yards
• Cell 5 (Crocus Ave to Baker Ave): +2,700,000 cubic yards

A portion of this gain, approximately 1,650,000 cubic yards, resulted from artificial beach replenishment projects.

In recent years, sediment has been eroding from North Wildwood and moving south into Wildwood. Each year, approximately 530,000 cubic yards of sediment travel southward, with the following distribution:

• 122,000 cubic yards return to North Wildwood.
• 124,000 cubic yards are lost offshore.
• 228,000 cubic yards deposit in Wildwood and Wildwood Crest.

Although the Cape May jetty significantly limits sediment bypass, small amounts of sand manage to pass around the structure.

Natural Issues (Storms)

Storms are one of the most significant issues the five mile island faces. Municipalities along the island have been constructing wooden bulkheads since the 1880’s, though in recent years these have been replaced by sheet pile or boulders. A plan is in place to build a continuous dune along the length of the island, but this remains unconstructed. Without these structures, severe overwash occurs, as observed in the 1960’s during the great ash wednesday storm.

Minor flooding occurs often, recently as frequently as 50 times annually. Moderate flooding is less frequent, at 1-2 times per year. Major flooding is rare – only 4 instances have been recorded in the 21st century. For context, minor flooding begins at 6.0 feet, moderate flooding begins at 7.0 feet, and major flooding is any water level higher than 8.0 feet. All measurements are in MLLW. 

Below is a list of the top five highest tides to ever strike our area, based on historical accounts and actual measurements:

1. 1821 Norfolk Long Island Hurricane – 14.56 feet (estimated) +/- 3.28 feet

The 1821 Norfolk Long Island Hurricane is one of the earliest recorded hurricanes to impact the Mid-Atlantic and Northeast regions. The storm likely made landfall somewhere around Cape May as a Category 3 storm, though some estimates have it as a Category 4 upon landfall. A storm like this would cover Delaware Avenue in over 8 feet of water.

2. 1778 Hurricane – 12.59 feet (estimated) +/- 3.28 feet

The 1778 Hurricane struck during the American Revolutionary War, adding to the challenges faced by the colonies. Though our island was uninhabited at the time, data from sediment cores on nearby islands tell us this storm probably allowed the ocean to meet the bay.

3. 1962 Great Ash Wednesday Storm – 10.45 feet (measured)

The Great Ash Wednesday Storm of 1962 was a powerful nor’easter that battered New Jersey for several days. This storm is particularly remembered for its prolonged impact and extensive property damage it caused in Cape May County (Fig 1). In The Wildwoods, many structures floated off of their foundations, burned to the ground, or were disintegrated by wave energy. Nearly all existing coastal protection structures failed.

4. 1944 Great Atlantic Hurricane – 9.50 feet (measured)

The 1944 Great Atlantic Hurricane was one of the most intense hurricanes of the 20th century to hit the East Coast. Limited coastal protection measures in place such as bulkheads and stockades failed during the storm.

5. 2016 Winter Storm Jonas – 9.44 feet (measured)

Jonas caused significant (and in some places record) coastal flooding, particularly in New Jersey and Delaware. Winter Storm Jonas damaged the manmade dune system in North Wildwood originally constructed in 2009, which breached at 3rd Avenue. Despite this, no oceanfront property damage was reported, entirely thanks to the existing coastal protection measures.

Manmade Issues (Barrier Migration)

Barrier islands like the Wildwoods rely on dynamic natural processes, including overwash, to maintain their structure and adapt to changing conditions. Overwash occurs when waves and storm surges overtop the dunes, carrying sediment from the oceanfront inland toward the back-barrier bays. This process redistributes sand across the island, helping to sustain its elevation, width, and resilience to future storms. However, urbanization and development on the Wildwoods have severely disrupted this natural mechanism.

Manmade dunes, such as those constructed in North Wildwood in 2009, are designed to prevent overwash and protect infrastructure. While effective in safeguarding oceanfront properties, these dunes block the inland transport of sand, disrupting the natural sediment-sharing process between the oceanfront and the back-barrier areas. Moreover, seawalls create rigid barriers along the shoreline, further preventing sediment from moving inland during storms. By halting overwash, they trap sediment at the oceanfront, which accelerates erosion at other parts of the coastline.

Overall, sediment transport is limited by these factors.

Sources:

Dohner, S. M., Trembanis, A. C., & Miller, D. C. (2016). A tale of three storms: Morphologic response of Broadkill Beach, Delaware, following Superstorm Sandy, Hurricane Joaquin, and Winter Storm Jonas. Geophysical Research Letters. https://doi.org/10.1002/2016GL070368

Gabriel, R. J., Lennon, G. P., & Weisman, R. N. (1983). The hydraulics of the Hereford Inlet and back bay system. Fritz Laboratory Reports Civil and Environmental Engineering, Lehigh University.

National Data Buoy Center. (n.d.). Station 44009. National Oceanic and Atmospheric Administration. https://www.ndbc.noaa.gov/station_page.php?station=44009

National Oceanic and Atmospheric Administration. (2024). Cape May (8536110) tides and currents. NOAA Tides and Currents. https://tidesandcurrents.noaa.gov/stationhome.html?id=8536110

National Oceanic and Atmospheric Administration. (2024). Stone Harbor (8535581) tides and currents. NOAA Tides and Currents. https://tidesandcurrents.noaa.gov/stationhome.html?id=8535581

National Oceanic and Atmospheric Administration. (2024). West Wildwood (8535726) tides and currents. NOAA Tides and Currents. https://tidesandcurrents.noaa.gov/stationhome.html?id=8535726

National Oceanic and Atmospheric Administration. (2024). Wildwood Crest (8535835) tides and currents. NOAA Tides and Currents. https://tidesandcurrents.noaa.gov/noaatidepredictions.html?id=8535835&legacy=1

New Jersey Sea Grant Consortium. (2023). State of the shore report 2023. https://njseagrant.org/wp-content/uploads/2023/05/Sos-Report-Single-Pages.pdf

Stockton Coastal Research Center. (2021). New Jersey Beach Profile Network 2020 annual report on shoreline changes in New Jersey’s four coastal counties: Raritan Bay to Delaware Bay, spring of 2019 through fall of 2020. https://stockton.edu/coastal-research-center/njbpn/NJBPN_2020.pdf

U.S. Army Corps of Engineers. (2014). Hereford Inlet to Cape May Inlet, Vol 1. https://www.nap.usace.army.mil/Portals/39/docs/Civil/Hereford_to_CapeMay/Volume_1_Hereford_FINAL.pdf