A flood barrier, surge barrier or storm surge barrier is a specific type of floodgate, designed to prevent a

storm surge A storm surge, storm flood, tidal surge, or storm tide is a coastal flood or tsunami-like phenomenon of rising water commonly associated with low-pressure weather systems, such as cyclones. It is measured as the rise in water level above the ...

spring tide Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tables ...

from flooding the protected area behind the barrier. A surge barrier is almost always part of a larger flood protection system consisting of floodwalls,

levee A levee ( or ), dike (American English), dyke (British English; see American and British English spelling differences#Miscellaneous spelling differences, spelling differences), embankment, floodbank, or stop bank is an elevated ridge, natural ...

s (also known as dikes), and other constructions and natural geographical features. Flood barrier may also refer to barriers placed around or at individual buildings to keep floodwaters from entering the buildings.

Examples

Delta Works

The Delta Works in the

Netherlands , Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...

is the largest flood protection project in the world. This project consists of a number of surge barriers, the Oosterscheldekering being the largest surge barrier in the world, long. Other examples include the Maeslantkering, Haringvlietdam and the Hartelkering.

Thames Barrier

The Thames Barrier is the world's second largest movable flood barrier (after the Oosterscheldekering and the Haringvlietdam) and is located downstream of central London. Its purpose is to prevent London from being flooded by exceptionally high

tide Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tables ...

s and storm surges moving up from the

North Sea The North Sea lies between Great Britain, Denmark, Norway, Germany, the Netherlands, Belgium, and France. A sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian Se ...

. It needs to be raised (closed) only during high tide; at ebb tide it can be lowered to release the water that backs up behind it. IHNC Surge Barrier Construction from Air

IHNC Surge Barrier Construction from Air

New Orleans

In 2007 the

United States Army Corps of Engineers The United States Army Corps of Engineers (USACE) is the military engineering branch of the United States Army. A direct reporting unit (DRU), it has three primary mission areas: Engineer Regiment, military construction, and civil wo ...

started construction of an ambitious project that aimed to prevent storm surges from flooding the city by 2011. The IHNC Lake Borgne Surge Barrier on the confluence of these waterways is the largest in the United States. It protects the city from the

Gulf of Mexico The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...

from flooding the area. The new Seabrook floodgate prevents a storm surge from entering from Lake Pontchartrain. The GIWW West Closure Complex closes the Gulf Intracoastal Waterway to protect the west side of the city. This complex is unique in that it contains the world's largest

pumping station Pumping stations, also called pumphouses, are public utility buildings containing pumps and equipment for pumping fluids from one place to another. They are critical in a variety of infrastructure systems, such as water supply, Land reclamation, ...

, necessary to pump out rainwater that is discharged in the protected side of the canal during a

hurricane A tropical cyclone is a rapidly rotating storm system with a low-pressure area, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Depending on its ...

Eider Barrage

The Eider Barrage is located at the mouth of the river Eider near Tönning on Germany's North Sea coast. Its main purpose is protection from

s by the North Seas. It is Germany's largest coastal protection structure.

St. Petersburg Dam

The Saint Petersburg Dam (officially called the Saint Petersburg Flood Prevention Facility Complex) is a barrier separating the

Gulf of Finland The Gulf of Finland (; ; ; ) is the easternmost arm of the Baltic Sea. It extends between Finland to the north and Estonia to the south, to Saint Petersburg—the second largest city of Russia—to the east, where the river Neva drains into it. ...

from

Neva Bay The Neva Bay (), also known as the Gulf of Kronstadt, is the easternmost part of the Gulf of Finland between Kotlin Island and the Neva River estuary where Saint Petersburg city centre is located. It has a surface area of . The entire bay has been ...

to protect the city of

Saint Petersburg Saint Petersburg, formerly known as Petrograd and later Leningrad, is the List of cities and towns in Russia by population, second-largest city in Russia after Moscow. It is situated on the Neva, River Neva, at the head of the Gulf of Finland ...

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

from

coastal flooding Coastal flooding occurs when dry and low-lying land is submerged (flooded) by seawater. The range of a coastal Flood, flooding is a result of the elevation of floodwater that penetrates the inland which is controlled by the topography of the coas ...

. The

Soviet Union The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

started construction of the barrier in 1978 and it was completed and made operational in 2011.

New England

The New Bedford Harbor Hurricane Barrier protects the city of

New Bedford, Massachusetts New Bedford is a city in Bristol County, Massachusetts, United States. It is located on the Acushnet River in what is known as the South Coast region. At the 2020 census, New Bedford had a population of 101,079, making it the state's ninth-l ...

, with a mostly immovable barrier of stone and fill. It has three land and one marine door for access in calm seas. The nearby Fox Point Hurricane Barrier protects the city of

Providence, Rhode Island Providence () is the List of capitals in the United States, capital and List of municipalities in Rhode Island, most populous city of the U.S. state of Rhode Island. The county seat of Providence County, Rhode Island, Providence County, it is o ...

. The US Army Corps of Engineers also owns and operates the hurricane barrier at Stamford, CT.

Venice

The MOSE Project is intended to protect the city of

Venice Venice ( ; ; , formerly ) is a city in northeastern Italy and the capital of the Veneto Regions of Italy, region. It is built on a group of 118 islands that are separated by expanses of open water and by canals; portions of the city are li ...

Italy Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...

, and the Venetian Lagoon from flooding.

River Foss Barrier

The River Foss, York, UK has a barrier to control the inflow of fast moving water from the River Ouse that may overspill its banks upstream the Foss and flood surrounding properties.

Proposed flood barriers

New York Harbor

The New York Harbor Storm-Surge Barrier is a proposed regional flood barrier system that would protect the harbor and the New York – New Jersey metropolitan region.

Ike Dike

The Ike Dike is a proposed flood barrier that would protect Houston, Texas.

Perimeter flood barriers

Flood barriers may be placed temporarily or permanently around individual buildings or at building entrances to keep floodwaters from entering those buildings. A wall constructed of sandbags is an example of a temporary barrier. A reinforced concrete wall is an example of a permanent barrier.U.S. Army Corps of Engineers, FLOOD PROOFING, EP 1165-2-314

Temporary barriers

Sandbags have traditionally been used as temporary flood barriers.

References

{{Rivers, streams and springs Dams Hydrology Water transport infrastructure