beach | National Geographic Society (2023)

A beach is a narrow, gently sloping strip of land that lies along the edge of an ocean, lake, or river. Materials such as sand, pebbles, rocks, and seashell fragments cover

beaches

.

Most

beach

materials are the products of weathering and erosion. Over many years, water and wind wear away at the land. The continual action of waves beating against a rocky cliff, for example, may cause some rocks to come loose. Huge boulders can be worn town to tiny grains of

sand

.

Beach

materials may travel long distances, carried by wind and waves. As the tide comes in, for example, it deposits ocean sediment. This

sediment

may contain

sand

, shells, seaweed, even marine organisms like crabs or sea anemones. When the

tide

goes out, it takes some

sediment

with it.

Tides

and ocean currents can carry

sediment

a few meters or hundreds of kilometers away.

Tides

and

currents

are the main way

beaches

are created, changed, and even destroyed, as the

currents

move

sediment

and debris from one place to another.

Beaches

are constantly changing.

Tides

and weather can alter

beaches

every day, bringing new materials and taking away others.

Beaches

also change seasonally. During the winter, storm winds toss

sand

into the air. This can sometimes erode

beaches

and create sandbars.

Sandbars

are narrow, exposed areas of

sand

and

sediment

just off the

beach

. During the summer, waves retrieve

sand

from

sandbars

and build the

beach

back up again. These seasonal changes cause

beaches

to be wider and have a gentle slope in the summer, and be narrower and steeper in the winter.

Beach Berms

Every

beach

has a beach profile. A

beach

profile

describes the landscape of the

beach

, both above the water and below it.

Beaches

can be warm, and rich in vegetation such as palm or mangrove trees.

Beaches

can also be barren desert coastlines. Other

beaches

are cold and rocky, while

beaches

in the Arctic and Antarctic are frozen almost all year.

The area above the water, including the intertidal zone, is known as the

beach

berm

.

Beach

berm

can include

vegetation

, such as trees, shrubs, or grasses. The most familiar characteristic of a

beach

berm

is its type of

sand

or rock.

Sandy
Most

beach

sand

comes from several different sources. Some

sand

may be eroded bits of a rocky reef just offshore. Others may be eroded rock from nearby

cliffs

. Pensacola

Beach

, in the U.S. state of Florida, for instance, has white,

sandy

beaches

. Some

sand

is eroded from rocks and minerals in the Gulf of Mexico. Most

sand

, however, is made of tiny particles of weathered quartz from the Appalachian Mountains, hundreds of kilometers away.

The

sandy

beaches

surrounding Chameis Bay, Namibia, are also full of quartz and seashells. However, the

beaches

of Chameis Bay contain another type of rock—diamonds. Mining companies have dug mines both on the

beach

and offshore to excavate these precious stones. Other gems, such as sapphires, emeralds, and garnets, are present on many

beaches

throughout the world, as tiny grains of

sand

.

Rocky
Some

beach

berms

are not

sandy

at all. They are covered with flat

pebbles

called shingles or rounded rocks known as cobbles. Such

beaches

are common along the coasts of the British Isles. Hastings

Beach

, a

shingle

beach

on the southern coast of England, has been a dock for fishing boats for more than a thou

sand

years.

A storm

beach

is a type of

shingle

beach

that is often hit by heavy storms. Strong waves and winds batter storm

beaches

into narrow, steep landforms. The

shingles

on storm

beaches

are usually small near the water and large at the highest elevation.

Other types of beaches
Some

beaches

, called barrier beaches, protect the mainland from the battering of ocean waves. These

beaches

may lie at the heads of islands called barrier islands. Many

barrier

beaches

and barrier islands stretch along the Atlantic and Gulf coasts of the United States. These narrow

beaches

form barriers between the open ocean and protected harbors, lagoons, and sounds.

Beaches

near rivers are often muddy or soft. Soil and

sediment

from the river is carried to the river’s mouth, sometimes creating a fertile

beach

. Hoi An, Vietnam, is an ancient town that sits on the estuary of the Thu Bon River and the South China Sea. Hoi An’s soft

beaches

serve as resort and tourist center.

Beach

berms

can be many different colors. Coral

beaches

, common on islands in the Caribbean Sea, are white and powdery. They are made from the eroded exoskeletons of tiny animals called

corals

. Some

coral

beaches

, such as Harbour Island, Bahamas, actually have pink

sand

. The

coral

that created these

beaches

were pink or red.

On some volcanic islands,

beaches

are jet-black. The

sand

on Punaluu

Beach

, Hawaii, is made of basalt, or lava that flowed into the ocean and instantly cooled. As it cooled, the

basalt

exploded into thou

sands

of tiny

fragments

. Some volcanic

beaches

, such as those on the South Pacific island of Guam, are green. The

basalt

in these

beaches

contained a large amount of the

mineral

olivine.

Threats to Beaches

Coastal Erosion
The most significant threat to

beaches

is natural

coastal

erosion

.

Coastal

erosion

is the natural process of the

beach

moving due to waves, storms, and wind.

Beaches

that experience consistent

coastal

erosion

are said to be in retreat.

Coastal

erosion

can be influenced by weather systems.

Beaches

on the island nation of Tuvalu, in the South Pacific, were retreating very quickly in the 1990s. Meteorologists linked this to the

weather system

known as the El Nino-Southern Oscillation (ENSO). As ENSO events slowed, Tuvalu’s

beaches

began to recover.

People respond to

coastal

erosion

in different ways. For years,

coastal

erosion

threatened the Cape Hatteras Lighthouse, on Hatteras Island in the U.S. state of North Carolina. The Cape Hatteras Lighthouse is the tallest lighthouse in the United States. For more than 100 years, it has warned ships of the low-lying

sandbars

and islands known as the Outer Banks.

Coastal

erosion

made the

beach

beneath the lighthouse unstable. In 2000, the entire lighthouse was moved 870 meters (2,870 feet) inland.

People also combat

coastal

erosion

with seawalls. These large structures, built of rock, plastic, or concrete, are constructed to prevent

sand

and other

beach

material from drifting away. Residents of Sea Gate, a community in Coney Island, New York, for instance, invested in a series of

seawalls

to protect their homes from powerful storms and waves from the Atlantic Ocean.

However, shifting

sand

is a natural part of the

beach

ecosystem.

Seawalls

may protect one section of

beach

while leaving another with little

sand

.

Seawalls

can also increase the speed at which

beaches

retreat. When

tides

and waves hit massive

seawalls

instead of

beaches

, they bounce back to the ocean with more energy. This tidal energy causes the

sand

in front of a

seawall

to erode much more quickly than it would without the

seawall

.

Hurricane

Sandy

was a deadly storm that struck the East Coast of the United States in October 2012. Many of the

seawalls

of Sea Gate crumbled, and more than 25 homes were lost.

Sea Level Rise
Beaches are also threatened by sea level rise. Sea levels have been gradually rising for many years, drowning some beaches completely.

New Moore Island, for example, was a small, uninhabited island in the Bay of Bengal. Both India and Bangladesh claimed the island, which was little more than a strip of sandy beach. In March 2010, rising sea levels drowned the island completely. New Moore Island is now a sandbar.

Development
Although the natural forces of wind and water can dramatically change

beaches

over many years, human activity can speed up the process. Dams, which block river

sediment

from reaching

beaches

, can cause

beaches

to retreat. In some places, large quantities of

sand

have been removed from

beaches

for use in making concrete.

Development

threatens the natural

landscape

of

beaches

. People develop homes and businesses near

beaches

for many reasons.

Beaches

are traditional tourist destinations. Places like the U.S. state of Hawaii, the island nation of Tahiti, and the islands of Greece are all economically dependent on tourism. Businesses, such as charter boat facilities, restaurants, and hotels, are built on the

beach

.

People also enjoy living near

beaches

.

Beachfront

property is often very highly valued. “The Hamptons” are exclusive

beach

communities on the eastern end of Long Island, New York. Homes in the Hamptons are some of the most expensive in the United States.

Development

can crowd

beaches

. As more buildings and other facilities are built,

beaches

become narrower and narrower. The natural, seasonal movement of

beach

sediment

is disrupted. Communities spend millions of dollars digging, or dredging,

sand

from one place to another in order to keep the

beach

the same all year.

Disappearing

beaches

are bad for coastal facilities. Natural

beaches

reduce the power of waves, wind, and storm surges. Without these

barrier

beaches

, waves and

storm surges

crash directly into buildings. In 1992, a storm swept away more than 200 homes in the Hamptons. It cost the government more than $80 million to replace the

barrier

beach

.

On Kauai, one of the islands in Hawaii, more than 70 percent of the

beach

is eroding, partly because of construction of

seawalls

and jetties, and from clearing out stream

mouths

. Geologists say Oahu, another Hawaiian island, has lost 25 percent of its shoreline.

Tourism

is the state’s main industry, so disappearing

beaches

are a major concern. The destruction of Hawaii’s

beaches

could also mean a loss of habitat for many plants and animals, some of which are already endangered.

Beach Pollution

Many

beaches

, especially in urban areas, are extremely polluted. Waves wash up

debris

from the ocean, while drainage pipes or rivers deposit waste from inland areas. Some of this waste includes sewage and other toxic chemicals. After strong storms, some

beaches

are closed. The amount of bacteria, raw sewage, and other

toxic

chemicals is hazardous to human health. Sometimes, it takes days or even weeks for the

toxic

waters to wash out to sea.

Beach

pollution also includes garbage, such as plastic bags, cans, and other containers from picnics. Medical waste, such as needles and surgical instruments, has even washed up on

beaches

.

All

beach

pollution

is harmful to wildlife. Birds may choke on small bits of plastic. Marine mammals such as sea lions may become tangled in ropes, twine, or other material. Floating plastic may prevent algae or sea plants from developing. This prevents animals that live in tide pools, such as sea anemones or sea stars, from finding nutrients.

Protecting Beaches

Reducing

pollution

is an important way to protect

beaches

. Visitors should never leave trash on the

beach

or throw it in the ocean.

Beachgoers

should also leave wildlife alone—including birds, plants, and seaweed. Taking shells or live animals from the

beach

destroys the

habitat

.

People can also protect

beaches

from excess

erosion

. Limiting

beachfront

development

can be an important step in protecting the natural

landscape

of

beaches

. Along some

beaches

, areas of

vegetation

known as “living shorelines” protect the

beach

ecosystem from

erosion

and protect the inland area from floods and

storm surges

.

In some places, machinery is used to dredge

sand

from the seabed just offshore and return it to the

beach

. Miami

Beach

, in the U.S. state of Florida, was restored by this method.

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