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A berm is a level space, shelf, or raised barrier (usually made of compacted soil) separating areas in a vertical way, especially partway up a long slope. It can serve as a terrace road, track, path, a fortification line, a border/separation barrier for navigation, good drainage, industry, or other purposes.
The word is one of Middle Dutch and came into usage in English via French. [1]
In medieval military engineering, a berm (or berme) was a level space between a parapet or defensive wall and an adjacent steep-walled ditch or moat. [1] It was intended to reduce soil pressure 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 of World War I, the name was applied to a similar feature at the lip of a trench, which served mainly as an elbow-rest for riflemen.
In modern military engineering, a berm is the earthen or sod wall or parapet, especially a low earthen wall adjacent to a ditch. The digging of the ditch (often by a bulldozer or military engineering vehicle) can provide the soil from which the berm is constructed. Walls constructed in this manner are an obstacle to vehicles, including most armoured fighting vehicles but are easily crossed by infantry. Because of the ease of construction, such walls can be made hundreds or thousands of kilometres long. A prominent example of such a berm is the 2,700 km (1,700 mi) Moroccan Western Sahara Wall.
Berms are also used to control erosion and sedimentation by reducing the rate of surface runoff. The berms either reduce the velocity of the water, or direct water to areas that are not susceptible to erosion, thereby reducing the adverse effects of running water on exposed topsoil. Following the 2010 Deepwater Horizon oil spill in the Gulf of Mexico, the construction of berms designed to prevent oil from reaching the fragile Louisiana wetlands (which would result in massive erosion) was proposed early on, and was officially approved by the federal government in mid-June, 2010, after numerous failures to stop and contain the oil leak with more advanced technologies. [2]
In coastal geography, a berm is a bank of sand or gravel ridge parallel to the shoreline and a few tens of centimetres high, created by wave action throwing material beyond the average level of the sea.
Earth is piled up against exterior walls and packed, sloping down away from the house. The roof may or may not be fully earth covered, and windows/openings may occur on one or more sides of the shelter. Due to the building being above ground, fewer moisture problems are associated with earth berming in comparison to underground/fully recessed construction.
For general applications, a berm is a physical, stationary barrier of some kind. For example, in highway construction, a berm is a noise barrier constructed of earth, often landscaped, running along a highway to protect adjacent land users from noise pollution. The shoulder of a road is also called a berm and in New Zealand the word sometimes describes a publicly owned grassed nature strip sometimes planted with trees alongside urban roads (usually called a verge). [3] In snowboard cross, a berm is a wall of snow built up in a corner. [4] In mountain biking, a berm is a banked turn formed by soil, commonly dug from the track, being deposited on the outer rim of the turn. In coastal systems, a berm is a raised ridge of pebbles or sand found at high tide or storm tide marks on a beach. In snow removal, a berm or windrow refers to the linear accumulation of snow cast aside by a plow. [5] Earth berms are used above particle accelerator tunnels to provide shielding from radiation. [6] In open-pit mining, a berm refers to dirt and rock piled alongside a haulage road or along the edge of a dump 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 machine on-site. [7] [8]
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. [9] At Baylor Ballpark, a baseball stadium on the campus of Baylor University, a berm is constructed down the right field line. The berm replaces bleachers, and general admission tickets are sold for fans who wish to sit on the grass or watch the game from the top of the hill.
Berms are also used as a method of environmental spill containment and liquid spill control. Bunding is the construction of a secondary impermeable barrier around and beneath storage or processing plant, sufficient to contain the plant's volume after a spill. This is often achieved on large sites by surrounding the plant with a berm. The US Environmental Protection Agency (EPA) requires that oils and fuels stored over certain volume levels be placed in secondary spill containment. Berms for spill containment are typically manufactured from polyvinyl chloride (PVC) or geomembrane fabric that provide a barrier to keep spills from reaching the ground or navigable waterways. Most berms have sidewalls to keep liquids contained for future capture and safe disposal.
Geotechnical engineering, also known as geotechnics, is the branch of civil engineering concerned with the engineering behavior of earth materials. It uses the principles of soil mechanics and rock mechanics to solve its engineering problems. It also relies on knowledge of geology, hydrology, geophysics, and other related sciences.
A levee, dike, dyke, embankment, floodbank, or stop bank is a structure used to keep the course of rivers from changing and to protect against flooding of the area adjoining the river or coast. It is usually earthen and often runs parallel to the course of a river in its floodplain or along low-lying coastlines.
Drainage is the natural or artificial removal of a surface's water and sub-surface water from an area with excess water. The internal drainage of most agricultural soils can prevent severe waterlogging, but many soils need artificial drainage to improve production or to manage water supplies.
An earth shelter, also called an earth house, earth bermed house, or underground house, is a structure with earth (soil) against the walls, on the roof, or that is entirely buried underground.
A trench is a type of excavation or depression in the ground that is generally deeper than it is wide, and narrow compared with its length.
A fortification is a military construction designed for the defense of territories in warfare, and is used to establish rule in a region during peacetime. The term is derived from Latin fortis ("strong") and facere.
A ditch is a small to moderate trench created to channel water. A ditch can be used for drainage, to drain water from low-lying areas, alongside roadways or fields, or to channel water from a more distant source for plant irrigation. Ditches are commonly seen around farmland, especially in areas that have required drainage, such as The Fens in eastern England and much of the Netherlands.
A combat engineer is a type of soldier who performs military engineering tasks in support of land forces combat operations. Combat engineers perform a variety of military engineering, tunnel and mine warfare tasks, as well as construction and demolition duties in and out of combat zones.
A gully is a landform created by running water, mass movement, or commonly a combination of both eroding sharply into soil or other relatively erodible material, typically on a hillside or in river floodplains or terraces. Gullies resemble large ditches or small valleys, but are metres to tens of metres in depth and width, are characterized by a distinct 'headscarp' or 'headwall' and progress by headward erosion. Gullies are commonly related to intermittent or ephemeral water flow, usually associated with localised intense or protracted rainfall events or snowmelt. Gullies can be formed and accelerated by cultivation practices on hillslopes in farmland, and they can develop rapidly in rangelands from existing natural erosion forms subject to vegetative cover removal and livestock activity.
A sandbag or dirtbag is a bag or sack made of hessian (burlap), polypropylene or other sturdy materials that is filled with sand or soil and used for such purposes as flood control, military fortification in trenches and bunkers, shielding glass windows in war zones, ballast, counterweight, and in other applications requiring mobile fortification, such as adding improvised additional protection to armored vehicles or tanks.
Earthbag construction is an inexpensive building method using mostly local soil to create structures which are both strong and can be quickly built.
Earthworks are engineering works created through the processing of parts of the earth's surface involving quantities of soil or unformed rock.
A fascine is a rough bundle of brushwood or other material used for strengthening an earthen structure, or making a path across uneven or wet terrain. Typical uses are protecting the banks of streams from erosion, covering marshland, or providing ground improvement in a manner similar to that of modern geotextiles.
A gabion is a cage, cylinder or box filled with rocks, concrete, or sometimes sand and soil for use in civil engineering, road building, military applications and landscaping.
Bunding, also called a bund wall, is a constructed retaining wall around storage "where potentially polluting substances are handled, processed or stored, for the purposes of containing any unintended escape of material from that area until such time as a remedial action can be taken."
An earth structure is a building or other structure made largely from soil. Since soil is a widely available material, it has been used in construction since prehistoric times. It may be combined with other materials, compressed and/or baked to add strength.
Landslide mitigation refers to several human-made activities on slopes with the goal of lessening the effect of landslides. Landslides can be triggered by many, sometimes concomitant causes. In addition to shallow erosion or reduction of shear strength caused by seasonal rainfall, landslides may be triggered by anthropic activities, such as adding excessive weight above the slope, digging at mid-slope or at the foot of the slope. Often, individual phenomena join to generate instability over time, which often does not allow a reconstruction of the evolution of a particular landslide. Therefore, landslide hazard mitigation measures are not generally classified according to the phenomenon that might cause a landslide. Instead, they are classified by the sort of slope stabilization method used:
Cellular confinement systems (CCS)—also known as geocells—are widely used in construction for erosion control, soil stabilization on flat ground and steep slopes, channel protection, and structural reinforcement for load support and earth retention. Typical cellular confinement systems are geosynthetics made with ultrasonically welded high-density polyethylene (HDPE) strips or novel polymeric alloy (NPA)—and expanded on-site to form a honeycomb-like structure—and filled with sand, soil, rock, gravel or concrete.
In military engineering, a ditch is an obstacle designed to slow down or break up an attacking force, while a trench is intended to provide cover to the defenders. In military fortifications the side of a ditch farthest from the enemy and closest to the next line of defence is known as the scarp while the side of a ditch closest to the enemy is known as the counterscarp.
The Deepwater Horizon oil spill occurred between 10 April and 19 September 2010 in the Gulf of Mexico. A variety of techniques were used to address fundamental strategies for addressing the spilled oil, which were: to contain oil on the surface, dispersal, and removal. While most of the oil drilled off Louisiana is a lighter crude, the leaking oil was of a heavier blend which contained asphalt-like substances. According to Ed Overton, who heads a federal chemical hazard assessment team for oil spills, this type of oil emulsifies well. Once it becomes emulsified, it no longer evaporates as quickly as regular oil, does not rinse off as easily, cannot be broken down by microbes as easily, and does not burn as well. "That type of mixture essentially removes all the best oil clean-up weapons", Overton said.
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