A berm is a level space, shelf, or raised barrier separating two areas. Berm originates in the Middle Dutch and German berme and came into usage in English via French.


In medieval military engineer
Military engineer
In military science, engineering refers to the practice of designing, building, maintaining and dismantling military works, including offensive, defensive and logistical structures, to shape the physical operating environment in war...

ing, a berm (or berme) was a level space between a parapet
A parapet is a wall-like barrier at the edge of a roof, terrace, balcony or other structure. Where extending above a roof, it may simply be the portion of an exterior wall that continues above the line of the roof surface, or may be a continuation of a vertical feature beneath the roof such as a...

 or defensive wall
Defensive wall
A defensive wall is a fortification used to protect a city or settlement from potential aggressors. In ancient to modern times, they were used to enclose settlements...

 and an adjacent steep-walled ditch
Ditch (fortification)
A ditch in military engineering is an obstacle, designed to slow down or break up an attacking force, while a trench is intended to provide cover to the defenders...

 or moat
A moat is a deep, broad ditch, either dry or filled with water, that surrounds a castle, other building or town, historically to provide it with a preliminary line of defence. In some places moats evolved into more extensive water defences, including natural or artificial lakes, dams and sluices...

. It was intended to reduce soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...

Pressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...

 on the walls of the excavated part to prevent its collapse. It also meant that debris dislodged from fortifications would not fall into (and fill) a ditch or moat.

In the trench warfare
Trench warfare
Trench warfare is a form of occupied fighting lines, consisting largely of trenches, in which troops are largely immune to the enemy's small arms fire and are substantially sheltered from artillery...

 of World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

, the name was applied to a similar feature at the lip of a trench
A trench is a type of excavation or depression in the ground. Trenches are generally defined by being deeper than they are wide , and by being narrow compared to their length ....

, which served mainly as an elbow-rest for riflemen.

Modern usage

In modern military engineering, berm has come to mean the earthen or sod
Sod or turf is grass and the part of the soil beneath it held together by the roots, or a piece of thin material.The term sod may be used to mean turf grown and cut specifically for the establishment of lawns...

A wall is a usually solid structure that defines and sometimes protects an area. Most commonly, a wall delineates a building and supports its superstructure, separates space in buildings into rooms, or protects or delineates a space in the open air...

 or parapet itself. The term especially refers to a low earthen wall adjacent to a ditch. The digging
Digging may refer to:* A form of excavation* Cave digging* Clam digging* Double digging, gardening technique* Dump digging* Gold digging** Gold-digging* Gum digging* Historical digging* Privy digging* Well digging...

 of the ditch (often by a bulldozer
A bulldozer is a crawler equipped with a substantial metal plate used to push large quantities of soil, sand, rubble, etc., during construction work and typically equipped at the rear with a claw-like device to loosen densely-compacted materials.Bulldozers can be found on a wide range of sites,...

 or military engineering vehicle) can provide the soil from which the berm is constructed. Walls constructed in this manner are an effective obstacle to vehicle
A vehicle is a device that is designed or used to transport people or cargo. Most often vehicles are manufactured, such as bicycles, cars, motorcycles, trains, ships, boats, and aircraft....

s, including most armoured fighting vehicle
Armoured fighting vehicle
An armoured fighting vehicle is a combat vehicle, protected by strong armour and armed with weapons. AFVs can be wheeled or tracked....

s, but are easily crossed by infantry
Infantrymen are soldiers who are specifically trained for the role of fighting on foot to engage the enemy face to face and have historically borne the brunt of the casualties of combat in wars. As the oldest branch of combat arms, they are the backbone of armies...

. Because of the ease of construction
In the fields of architecture and civil engineering, construction is a process that consists of the building or assembling of infrastructure. Far from being a single activity, large scale construction is a feat of human multitasking...

, such walls can be made hundreds or thousands of kilometres long.

Erosion control

Berms are also used to control erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...

 and sediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....

ation by reducing the rate of surface runoff
Surface runoff
Surface runoff is the water flow that occurs when soil is infiltrated to full capacity and excess water from rain, meltwater, or other sources flows over the land. This is a major component of the water cycle. Runoff that occurs on surfaces before reaching a channel is also called a nonpoint source...

. The berms either reduce the velocity
In physics, velocity is speed in a given direction. Speed describes only how fast an object is moving, whereas velocity gives both the speed and direction of the object's motion. To have a constant velocity, an object must have a constant speed and motion in a constant direction. Constant ...

 of the water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

, or direct water to areas that are not susceptible to erosion, thereby reducing the adverse effects of running water on exposed topsoil
Topsoil is the upper, outermost layer of soil, usually the top to . It has the highest concentration of organic matter and microorganisms and is where most of the Earth's biological soil activity occurs.-Importance:...

. Following the 2010 Deepwater Horizon
Deepwater Horizon
Deepwater Horizon was an ultra-deepwater, dynamically positioned, semi-submersible offshore oil drilling rig owned by Transocean. Built in 2001 in South Korea by Hyundai Heavy Industries, the rig was commissioned by R&B Falcon, which later became part of Transocean, registered in Majuro, Marshall...

 oil spill in the Gulf of Mexico, the construction of berms designed to prevent oil from reaching the fragile Louisiana
Louisiana is a state located in the southern region of the United States of America. Its capital is Baton Rouge and largest city is New Orleans. Louisiana is the only state in the U.S. with political subdivisions termed parishes, which are local governments equivalent to counties...

 wetlands (which would result in massive erosion) was proposed early on, and was officially approved by the federal government
Federal government of the United States
The federal government of the United States is the national government of the constitutional republic of fifty states that is the United States of America. The federal government comprises three distinct branches of government: a legislative, an executive and a judiciary. These branches and...

 in mid-June, 2010, after numerous failures to stop and contain the oil leak with more advanced technologies.

Uses in other applications

The Oxford English dictionary gives some meanings other than military:
  • In geology a flat region on the side of a valley that forms a terrace above the current valley floor is called a strath
    A strath is a large valley, typically a river valley that is wide and shallow .An anglicisation of the Gaelic word srath, it is one of many that have been absorbed into common use in the English language...

    , if it is coupled to the valley shoulder a berm.
  • A name for either side of the flood-plane of the River Nile: "The water level in the winter was some fifty centimètres below the general level of the berm. (Westm. Gaz. 10 July 1900 2/2 )".
  • In the United States a berm-bank is the "bank of a canal opposite the towing-path"

Berm has been adopted as a wider term usually used to describe a physical, stationary barrier of some kind:
  • In modern highway
    A highway is any public road. In American English, the term is common and almost always designates major roads. In British English, the term designates any road open to the public. Any interconnected set of highways can be variously referred to as a "highway system", a "highway network", or a...

     construction, a berm is a noise barrier
    Noise barrier
    A noise barrier is an exterior structure designed to protect sensitive land uses from noise pollution...

     constructed of earth, often landscaped, running along a highway to protect adjacent land users from noise pollution
    Noise pollution
    Noise pollution is excessive, displeasing human, animal or machine-created environmental noise that disrupts the activity or balance of human or animal life...

  • In industrial construction, Berms are often used as a safety measure to redirect spills, explosive forces, etc. in the case of an accident.
  • In the natural building
    Natural building
    A natural building involves a range of building systems and materials that place major emphasis on sustainability. Ways of achieving sustainability through natural building focus on durability and the use of minimally processed, plentiful or renewable resources, as well as those that, while...

     movement, berming refers to piling earth against an exterior wall to create thermal mass
    Thermal mass
    Thermal mass is a concept in building design which describes how the mass of the building provides "inertia" against temperature fluctuations, sometimes known as the thermal flywheel effect...

     or reduce the visible footprint of an earth-sheltered home.
  • In archaeology
    Archaeology, or archeology , is the study of human society, primarily through the recovery and analysis of the material culture and environmental data that they have left behind, which includes artifacts, architecture, biofacts and cultural landscapes...

    , a berm is a narrow space, such as that between banks and ditches. It can also refer to a raised linear bank separating two areas.
  • In Pennsylvania
    The Commonwealth of Pennsylvania is a U.S. state that is located in the Northeastern and Mid-Atlantic regions of the United States. The state borders Delaware and Maryland to the south, West Virginia to the southwest, Ohio to the west, New York and Ontario, Canada, to the north, and New Jersey to...

    , Ohio
    Ohio is a Midwestern state in the United States. The 34th largest state by area in the U.S.,it is the 7th‑most populous with over 11.5 million residents, containing several major American cities and seven metropolitan areas with populations of 500,000 or more.The state's capital is Columbus...

    , Indiana
    Indiana is a US state, admitted to the United States as the 19th on December 11, 1816. It is located in the Midwestern United States and Great Lakes Region. With 6,483,802 residents, the state is ranked 15th in population and 16th in population density. Indiana is ranked 38th in land area and is...

    , and West Virginia
    West Virginia
    West Virginia is a state in the Appalachian and Southeastern regions of the United States, bordered by Virginia to the southeast, Kentucky to the southwest, Ohio to the northwest, Pennsylvania to the northeast and Maryland to the east...

     the word "berm" refers to the shoulder
    Shoulder (road)
    A hard shoulder, or simply shoulder, is a reserved area by the verge of a road or motorway. Generally it is kept clear of motor vehicle traffic...

     of a highway.
  • In some regions a berm refers to a road verge, or strip of grass that is located between a sidewalk
    A sidewalk, or pavement, footpath, footway, and sometimes platform, is a path along the side of a road. A sidewalk may accommodate moderate changes in grade and is normally separated from the vehicular section by a curb...

     and the curb
    Curb may refer to:* Curb , or kerb, the edge where a raised pavement/sidewalk/footpath, road median, or road shoulder meets an unraised street or other roadway.* Curb Records, a record label started by Mike Curb in 1973....

     of a street
    A street is a paved public thoroughfare in a built environment. It is a public parcel of land adjoining buildings in an urban context, on which people may freely assemble, interact, and move about. A street can be as simple as a level patch of dirt, but is more often paved with a hard, durable...

  • In Bicycle Motocross (BMX)
    Bicycle motocross or BMX refers to the sport in which the main goal is extreme racing on bicycles in motocross style on tracks with inline start and expressive obstacles, and it is also the term that refers to the bicycle itself that is designed for dirt and motocross cycling.- History :BMX started...

     bicycle racing
    Bicycle racing
    Bicycle racing is a competition sport in which various types of bicycles are used. There are several categories of bicycle racing including road bicycle racing, cyclo-cross, mountain bike racing, track cycling, BMX, bike trials, and cycle speedway. Bicycle racing is recognised as an Olympic sport...

     mountain biking
    Mountain biking
    Mountain biking is a sport which consists of riding bicycles off-road, often over rough terrain, using specially adapted mountain bikes. Mountain bikes share similarities with other bikes, but incorporate features designed to enhance durability and performance in rough terrain.Mountain biking can...

     (MTB) Supercross
    Supercross is a motorcycle racing sport involving off-road motorcycles on an artificially-made dirt tracks consisting of steep jumps and obstacles. Professional supercross contest races are held almost exclusively within professional baseball and football stadiums.-History:Supercross was derived...

     and Motocross
    Motocross is a form of motorcycle sport or all-terrain vehicle racing held on enclosed off road circuits. It evolved from trials, and was called scrambles, and later motocross, combining the French moto with cross-country...

    , a berm refers to a banked turn made from dirt with a tight radius
    In classical geometry, a radius of a circle or sphere is any line segment from its center to its perimeter. By extension, the radius of a circle or sphere is the length of any such segment, which is half the diameter. If the object does not have an obvious center, the term may refer to its...

  • In Snowboard Cross, a berm is a wall of snow
    Snow is a form of precipitation within the Earth's atmosphere in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by...

     built up in a corner.
  • In coastal systems, a berm is a raised ridge of pebble
    A pebble is a clast of rock with a particle size of 4 to 64 millimetres based on the Krumbein phi scale of sedimentology. Pebbles are generally considered to be larger than granules and smaller than cobbles . A rock made predominantly of pebbles is termed a conglomerate...

    s or sand
    Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...

     found at 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 the sun and the rotation of the Earth....

     or storm
    A storm is any disturbed state of an astronomical body's atmosphere, especially affecting its surface, and strongly implying severe weather...

     tide marks on a beach
    A beach is a geological landform along the shoreline of an ocean, sea, lake or river. It usually consists of loose particles which are often composed of rock, such as sand, gravel, shingle, pebbles or cobblestones...

  • In snow removal, a berm or windrow
    A windrow is a row of cut hay or small grain crop. It is allowed to dry before being baled, combined, or rolled. For hay, the windrow is often formed by a hay rake, which rakes hay that has been cut by a mower machine or by scythe into a row, or it may naturally form as the hay is mowed...

     refers to the linear accumulation of snow cast aside by a plow
    A snowplow is a device intended for mounting on a vehicle, used for removing snow and ice from outdoor surfaces, typically those serving transportation purposes...

  • In open-pit mining
    Open-pit mining
    Open-pit mining or opencast mining refers to a method of extracting rock or minerals from the earth by their removal from an open pit or borrow....

    , a berm refers to dirt and rock
    Rock (geology)
    In geology, rock or stone is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic...

     piled alongside a haulage road or along the edge of a dump
    Dump generally refers to a place for disposal of domestic waste. See articles at midden and landfill.-Other uses:The word has other uses alone or in combination and may refer to:* Dump , a Unix program for backing up file systems...

     point. Intended as a safety measure, they are commonly required by government organizations to be at least half as tall as the wheels of the largest mining
    Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...

     machine on-site.
  • At some sports stadiums (mainly baseball
    Baseball is a bat-and-ball sport played between two teams of nine players each. The aim is to score runs by hitting a thrown ball with a bat and touching a series of four bases arranged at the corners of a ninety-foot diamond...

    , in the US), the berm is a grass
    Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...

     area along the fence
    A fence is a freestanding structure designed to restrict or prevent movement across a boundary. It is generally distinguished from a wall by the lightness of its construction: a wall is usually restricted to such barriers made from solid brick or concrete, blocking vision as well as passage .Fences...

     in foul and fair territory where spectators may sit and view games. Grassy berms are mainly found at smaller ballparks, such as for spring training
    Spring training
    In Major League Baseball, spring training is a series of practices and exhibition games preceding the start of the regular season. Spring training allows new players to try out for roster and position spots, and gives existing team players practice time prior to competitive play...

    , minor league teams, or college baseball
    College baseball
    College baseball is baseball that is played on the intercollegiate level at institutions of higher education. Compared to football and basketball, college competition in the United States plays a less significant contribution to cultivating professional players, as the minor leagues primarily...

    . Admission prices are typically quite low and help attract fans. One such example is Bright House Field in Clearwater, Florida
    Clearwater, Florida
    Clearwater is a city located in Pinellas County, Florida, US, nearly due west of Tampa and northwest of St. Petersburg. In the west of Clearwater lies the Gulf of Mexico and in the east lies Tampa Bay. As of the 2000 census, the city had a total population of 108,787. It is the county seat of...

    , where the Philadelphia Phillies
    Philadelphia Phillies
    The Philadelphia Phillies are a Major League Baseball team. They are the oldest continuous, one-name, one-city franchise in all of professional American sports, dating to 1883. The Phillies are a member of the Eastern Division of Major League Baseball's National League...

     train and the minor league Clearwater Threshers
    Clearwater Threshers
    The Clearwater Threshers are a minor league baseball team that currently plays in the Florida State League. Since 2004, the team competes in the West Division....

  • Disneyland Park in Anaheim, California
    Anaheim, California
    Anaheim is a city in Orange County, California. As of the 2010 United States Census, the city population was about 365,463, making it the most populated city in Orange County, the 10th most-populated city in California, and ranked 54th in the United States...

     is surrounded by a berm that was implemented to maintain the illusion of the park being a magical place removed from the real world. In many locations, the train
    Disneyland Railroad
    The Disneyland Railroad , originally the Santa Fe & Disneyland Railroad, is a narrow gauge railroad at Disneyland, Anaheim, California, United States, that was inaugurated on the park's live television preview on July 17, 1955. This live steam railway was constructed for $240,000; each of the...

     that travels around the park rests upon or next to this berm. Some attractions, such as the Haunted Mansion
    Haunted Mansion
    The Haunted Mansion is a dark ride located at Disneyland, the Magic Kingdom at Walt Disney World and Tokyo Disneyland. A significantly re-imagined incarnation of the ride, known as Phantom Manor, is located in Disneyland Paris...

     and Pirates of the Caribbean, are too large to fit entirely within the park, and thus are partly constructed outside the berm. Also, Mickey's Toontown
    Mickey's Toontown
    At the Magic Kingdom, Mickey's Toontown Fair initially opened as Mickey's Birthdayland on June 18, 1988. It became Mickey's Starland on May 26, 1990, and Mickey's Toontown Fair on October 1, 1996...

     was added to the park in 1993, and the lack of space necessitated that it lay almost entirely outside the berm.
  • Fabric products designed to provide secondary containment against leaks and spills are also known as berms. Placed under or around equipment, it acts as a barrier between machinery or fueling operations and serves to protect the environment
    Environment (biophysical)
    The biophysical environment is the combined modeling of the physical environment and the biological life forms within the environment, and includes all variables, parameters as well as conditions and modes inside the Earth's biosphere. The biophysical environment can be divided into two categories:...

     beneath. One such example is the Insta-Berm.
  • Physical security systems employ berms to exclude hostile vehicles and slow attackers on foot (similar to the military application without the trench). Security berms are common around military and nuclear facilities. An example is the berm proposed for Vermont Yankee nuclear power plant in Vermont.
  • Plans to build multiple berms off the wetlands of Louisiana
    Louisiana is a state located in the southern region of the United States of America. Its capital is Baton Rouge and largest city is New Orleans. Louisiana is the only state in the U.S. with political subdivisions termed parishes, which are local governments equivalent to counties...

     to protect the fragile ecosystem from the Deepwater Horizon
    Deepwater Horizon
    Deepwater Horizon was an ultra-deepwater, dynamically positioned, semi-submersible offshore oil drilling rig owned by Transocean. Built in 2001 in South Korea by Hyundai Heavy Industries, the rig was commissioned by R&B Falcon, which later became part of Transocean, registered in Majuro, Marshall...

     oil spill were announced in June 2010, first by local authorities and eventually by President
    A president is a leader of an organization, company, trade union, university, or country.Etymologically, a president is one who presides, who sits in leadership...

     Barack Obama
    Barack Obama
    Barack Hussein Obama II is the 44th and current President of the United States. He is the first African American to hold the office. Obama previously served as a United States Senator from Illinois, from January 2005 until he resigned following his victory in the 2008 presidential election.Born in...

    . It is unclear whether these berms will provide any benefit by keeping oil offshore; that is, the benefits may be purely psychological. Experts seem to disagree on this; further input on the merits (or lack thereof) of this project are needed, especially as the announcement of this project is a recent development, and nothing on this scale, in this type of situation, has ever been attempted. Louisiana Governor
    A governor is a governing official, usually the executive of a non-sovereign level of government, ranking under the head of state...

     Bobby Jindal
    Bobby Jindal
    Piyush "Bobby" Jindal is the 55th and current Governor of Louisiana and formerly a member of the United States House of Representatives. He is a member of the Republican Party....

     has been a staunch advocate for the building of these berms. In the case of protecting wetlands with narrow channels into the Gulf of Mexico
    Gulf of Mexico
    The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...

    , berms may theoretically be more effective than in open water. But, as it has never been attempted, this remains unproven.
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