Turpentine (which is also called spirit of turpentine, oil of turpentine, terebenthine, terebenthene, terebinthine and, colloquially, turps) is a fluid obtained by the distillation of resin harvested from living trees, mainly pines. Principally used as a specialized solvent, it is also a source of material for organic syntheses.
Forestry is one of the main economic sectors of Chile, representing 14% of the value of the country's total exports. This places the forestry sector in Chile as the second largest export sector behind copper mining. From 1970 to 2005 planted forest surface in Chile grew from 300,000 ha to more than 2.07 million ha. In 2019 Chile had slightly more than 2,3 million ha of forest plantations of which 1,3 million ha were Pinus radiata and 0,9 million ha were of Eucalyptus globulus and Eucalyptus nitens. In 2006 70% of Chile's forestry production went to export, and the industry employed more than 150,000 workers. By 2020 people employed in the sector were down to 112,200.
The wave of forest plantations that begun in the 1970s was initially a response to severe soil erosion that affected much of the country. There was a broad support for plantations when these were first implemented but by the 1980s a conservationist critique had grown exposing the adverse effects of plantations on certain plant and animal species, on biodiversity and on water resources. In many cases the establishment of plantations meant not reforestation but the replacement of existing forests with plantations.
The growth of the forestry sector since the 1980s is the consequence of growth of the export-oriented economy in Chile. Critics argue it has created an enclave economy. In the area of Cañete and Tirúa forestry companies have been accused of contributing to the displacement of indigenous Mapuche communities. In the last decades the communities of Temucuicui have had a conflict, at times physically violent, with the forestry company Forestal Mininco, leading to the detention and imprisonment of community members in the prisons of Angol and Cañete. (Full article...)
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Sir Dietrich BrandisKCIEFRS (31 March 1824 – 28 May 1907) was a German-British botanist and forestry academic and administrator, who worked with the British Imperial Forestry Service in colonial India for nearly 30 years. He joined the British civil service in Burma in 1856, shortly afterwards became head of the British forestry administration in all of Burma, and served as Inspector General of Forests in India from 1864 to 1883. He returned to Europe in 1883, dividing his time between Bonn and Greater London. In retirement he dedicated himself to scholarly work, resulting in the book Indian Trees (1906), his magnum opus. Brandis is considered the father of tropicalforestry and has also been described as the father of scientific forestry. In addition to his work in India, he also had a significant influence on forest management in the United States. (Full article...)
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Natural resources are materials that occur in a natural form within environments. These can be classified as either biotic or abiotic on the basis of their origin. The landmass and the territorial waters of Cambodia contain a rather moderate amount, array and variety of resources. Apart from water, abiotic resources, such as minerals are generally rare. Still, advanced geo-scientific technologies have produced remarkable results and re-assessments in recent years, such as the localization of offshore oil and gas depots in the Gulf of Thailand. Cambodia, on the other hand possesses a relatively wide range of biotic resources, in particular timber, forest products, rare plants and a fauna of great diversity. (Full article...)
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High lead logging is a method of cable logging using a spar, yarder and loader. It was developed by Oscar Wirkkala. It is accomplished with two lines (cables) and two winches (or cable drums). The mainline or yarding line extends out from one winch, while a second usually lighter line called the haulback line extends out from the other winch to a 'tail block' or pulley at the tail (back) end of the logging site, and passes through the tail block and connects to the main line. Butt rigging is installed where the two lines join and the logs are hooked to the butt rigging with chokers. The procedure is to wind up the main line and the logs are pulled in, wind up the haulback and the butt rigging is pulled out for more logs or another 'turn'.
The "high lead" feature is added by elevating both lines near the winch or 'head' end. This is accomplished by running the lines through a block (pulley) called the "head block" because it is on the head end of the project. Early on, it was customary to trim and top a tree making it into a 'spar pole' or 'spar tree' for the purpose of supporting the head blocks but gradually the use of wooden spars gave way over the 20th century to the use of steel spars stood up for the purpose. In any event the spars are supported by a number of guy wires.
The reason for elevating the lines (cables) at the head end is to assist in pulling the logs free of obstructions on the ground. Also if the trees are being partially lifted as they are transported it is less disruptive to the ground which can be an environmental issue.
High lead is a popular method of logging on the West Coast of America.
Agroforestry can be practiced for economic, environmental, and social benefits, and can be part of sustainable agriculture. Apart from production, benefits from agroforestry include improved farm productivity, healthier environments, reduction of risk for farmers, beauty and aesthetics, increased farm profits, reduced soil erosion, creating wildlife habitat, less pollution, managing animal waste, increased biodiversity, improved soil structure, and carbon sequestration.
Agroforestry practices are especially prevalent in the tropics, especially in subsistence smallholdings areas, with particular importance in sub-Saharan Africa. Due to its multiple benefits, for instance in nutrient cycle benefits and potential for mitigating droughts, it has been adopted in the USA and Europe. (Full article...)
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The forests of Germany covers 11.4 million hectares (28.2 Acres), 32 percent of the total area of the country (as of 2012). In the German forests grow about 90 billion trees with a total wood stock of 3.7 billion cubic meters.
The definition of the Federal Forest Act (BWaldG) for forest is: "any area planted with forest plants. Forest also includes clear-cut or shaded ground areas, forest roads, forest clearance and securing strips, forest meadows and clearings, forest meadows, grass clearing areas, wood storage areas and other areas associated with and serving the forest." (Full article...)
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Taiga Rescue Network (TRN) was an international network of more than 200 non-governmental organizations, indigenous peoples and individuals working to defend the world's boreal forests, also known as Taiga. TRN was established in 1992 to give a voice to support, link and publicize local struggles fighting for the boreal forests and its peoples. TRN no longer exists. In 2010, TRN held its last conference in Sweden. The website remained online until April 2013. (Full article...)
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Fern (also Stichting Fern) is a Dutch foundation created in 1995. It is an international Non-Governmental Organization (NGO) set up to keep track of the European Union's (EU) involvement in forests and coordinate NGO activities at the European level. Fern works to protect forests and the rights of people who depend on them.
Although Fern is known for its work on forests, since 2000 it has widened its scope to include climate, forest governance, trade and sustainable supply chain as many of the decisions made in these areas have a direct or indirect impact on forests and forest peoples' rights. In all these areas, Fern collaborates with many environmental groups and social movements across the world.
Fern's official mission statement is "To increase understanding of, and access to, European policy making; and to campaign for policies and practices in Europe that focus on forests and forest peoples’ rights and deliver economic, environmental and social justice globally.” (Full article...)
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The General Revision Act (sometimes Land Revision Act) of 1891, also known as the Forest Reserve Act of 1891, was a federal law signed in 1891 by President Benjamin Harrison. The Act reversed previous policy initiatives, such as the Timber Culture Act of 1873, which did not preclude land fraud by wealthy individuals and corporations. The acquisition of vast mineral and timber resources in the Western United States was often cited as a governing motive for such individuals and corporations to claim land rights for future settlement and resource depletion activities. The legacy of the General Revision Act of 1891 is frequently credited as its serving as a catalyst to a series of federal land reform initiatives, notably under President Theodore Roosevelt. From the Reclamation Act of 1902 to the formation of the United States Forest Service in 1905, the General Revision Act of 1891 acted as a critical first piece of federal legislation granting increased plots of publicly allotted land and decreased extraction rights to privately held western land owners in the early 20th century.
The law gives the President of the United States the authority to unilaterally set aside forest reserves from land in the public domain. After newspapers began to publicize the fraud and speculation under the previous Timber Culture Act of 1873 that granted additional land to homesteaders agreeing to plant trees, scientists of the American Association for the Advancement of Science (AAAS) joined with the American Forestry Association to advocate for stronger laws for the management of the nation's forest land. The resulting act, passed by the 51st United States Congress and signed into law by President Benjamin Harrison on March 3, 1891, set out to both protect local watersheds from flooding and erosion as well as to prevent over-exploitation of the country's timber supply.
Under the act, President Harrison issued proclamations establishing 13 million acres (53,000 km2) of land as forest reserves; President Grover Cleveland proclaimed 25 million acres (100,000 km2) and President William McKinley 7 million acres (28,000 km2). In 1907 a law was passed limiting presidential authority to designate forest reserves in certain states and renamed the existing "forest reserves" as "national forests". (Full article...)
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A skidder is any type of heavy vehicle used in a logging operation for pulling cut trees out of a forest in a process called "skidding", in which the logs are transported from the cutting site to a landing. There they are loaded onto trucks (or in times past, railroad cars or flumes), and sent to the mill. One exception is that in the early days of logging, when distances from the timberline to the mill were shorter, the landing stage was omitted altogether, and the "skidder" would have been used as the main road vehicle, in place of the trucks, railroad, or flume. Modern forms of skidders can pull trees with a cable and winch (cable skidder), just like the old steam donkeys, or with a hydraulic grapple either on boom (grapple skidder) or on the back of the frame (clambunk skidder). (Full article...)
Interception refers to precipitation that does not reach the soil, but is instead intercepted by the leaves, branches of plants and the forest floor. It occurs in the canopy (i.e. canopy interception), and in the forest floor or litter layer (i.e. forest floor interception ). Because of evaporation, interception of liquid water generally leads to loss of that precipitation for the drainage basin, except for cases such as fog interception, but increase flood protection dramatically, Alila et al., (2009). Intercepted snowfall does not result in any notable amount of evaporation, and most of the snow falls off the tree by wind or melts. However, intercepted snow can more easily drift with the wind, out of the watershed. Conifers have a greater interception capacity than hardwoods. Their needles gives them more surface area for droplets to adhere to, and they have foliage in spring and fall, therefore interception also depends on the type of vegetation in a wooded area.
Mitscherlich in 1971 calculated the water storage potential as interception values for different species and stand densities. A storm event might produce 50 – 100 mm of rainfall and 4 mm might be the maximum intercepted in this way. Grah and Wilson in 1944 did sprinkling experiments where they watered plants to see how much of the intercepted is kept after watering stops.
Trees like Norway maple and a small-leaved lime have an interception of approximately 38% of the gross precipitation in temperate climate.
The interception depends on the leaf area index and what kind of leaves they are.
The Rainforest Alliance is an international non-governmental organization (NGO) with staff in more than 20 countries and operations in more than 70 countries. It was founded in 1987 by Daniel Katz, an American environmental activist, who serves as the chair of the board of directors. The NGO states that its mission is "to create a more sustainable world by using social and market forces to protect nature and improve the lives of farmers and forest communities." Its work includes the provision of an environmental certification for sustainability in agriculture. In parallel to its certification program, the Rainforest Alliance develops and implements long-term conservation and community development programs in a number of critically important tropical landscapes where commodity production threatens ecosystem health and the well-being of rural communities.
The Rainforest Alliance is a product-oriented multistakeholder governance group combining the interests of companies, farmers, foresters, communities, and consumers to produce sustainable and harmonious goods. (Full article...)
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A log flume is a watertight flume constructed to transport lumber and logs down mountainous terrain using flowing water. Flumes replaced horse- or oxen-drawn carriages on dangerous mountain trails in the late 19th century. Logging operations preferred flumes whenever a reliable source of water was available. Flumes were cheaper to build and operate than logging railroads. They could span long distances across chasms with more lightweight trestles.
The success of agriculture during the Estado Novo (New State), with Getúlio Vargas, led to the expression, "Brazil, breadbasket of the world".
As of 2009, Brazil had about 106,000,000 hectares (260,000,000 acres) of undeveloped fertile land – a territory larger than the combined area of France and Spain.
According to a 2008 IBGE study, despite the global financial crisis, Brazil had record agricultural production, with growth of 9.1%, principally motivated by favorable weather. The production of grains in the year reached an unprecedented 145,400,000 tons. That record output employed an additional 4.8% in planted area, totalling 65,338,000 hectares and producing $148 billion Reals. The principal products were corn (13.1% growth) and soy (2.4% growth).
The southern one-half to two-thirds of Brazil has a semi-temperate climate, higher rainfall, more fertile soil, more advanced technology and input use, adequate infrastructure and more experienced farmers. This region produces most of Brazil's grains, oilseeds, and exports.
The drought-ridden northeast region and Amazon basin lack well-distributed rainfall, good soil, adequate infrastructure and development capital. Although mostly occupied by subsistence farmers, both regions are increasingly important as exporters of forest products, cocoa and tropical fruits. Central Brazil contains substantial areas of grassland. Brazilian grasslands are far less fertile than those of North America, and are generally suited only for grazing. (Full article...)
Botany, also called plant science (or plant sciences), plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek word βοτάνη (botanē) meaning "pasture", "herbs" "grass", or "fodder"; βοτάνη is in turn derived from βόσκειν (boskein), "to feed" or "to graze". Traditionally, botany has also included the study of fungi and algae by mycologists and phycologists respectively, with the study of these three groups of organisms remaining within the sphere of interest of the International Botanical Congress. Nowadays, botanists (in the strict sense) study approximately 410,000 species of land plants of which some 391,000 species are vascular plants (including approximately 369,000 species of flowering plants), and approximately 20,000 are bryophytes.
Botany originated in prehistory as herbalism with the efforts of early humans to identify – and later cultivate – plants that were edible, poisonous, and possibly medicinal, making it one of the first endeavours of human investigation. Medieval physic gardens, often attached to monasteries, contained plants possibly having medicinal benefit. They were forerunners of the first botanical gardens attached to universities, founded from the 1540s onwards. One of the earliest was the Padua botanical garden. These gardens facilitated the academic study of plants. Efforts to catalogue and describe their collections were the beginnings of plant taxonomy, and led in 1753 to the binomial system of nomenclature of Carl Linnaeus that remains in use to this day for the naming of all biological species.
Wood is the main fuel for cooking and other domestic requirements. It is not surprising that population pressure has had an adverse effect on the indigenous forests. By 1980 only about 16 percent of the land was forested, and forests had all but disappeared from the densely populated and intensively cultivated deltaic plain. Aid organizations in the mid-1980s began looking into the possibility of stimulating small-scale forestry to restore a resource for which there was no affordable substitute. Bangladesh Forest Research Institute (BFRI) is the government organization under Ministry of Environment, Forest and Climate Change for research in this sector which was established in 1955 at Sholoshahar, Chittagong city.
The largest areas of forest are in the Chittagong Hill Tracts and the Sundarbans. The evergreen and deciduous forests of the Chittagong Hills cover more than 4,600 square kilometres (1,800 sq mi) and are the source of teak for heavy construction and boat building, as well as other forest products. Domesticated elephants are still used to haul logs. The Sundarbans, a tidal mangrove forest covering nearly 6,000 square kilometres (2,300 sq mi) along the Bay of Bengal, is the source of timber used for a variety of purposes, including pulp for the domestic paper industry, poles for electric power distribution, and leaves for thatching for dwellings. The total percentage of forests are 10.98%.[citation needed] (Full article...)
Resource Extraction Monitoring (REM) is a non-profit organisation that provides independent monitoring to ensure that laws relating to the extraction of natural resources are enforced. It was founded in 2003 by experts with over 15 years of monitoring experience. The head office is in the UK, with local offices in countries where major projects are taking place.
The organisation bridges the gap between governments, environmental and human rightsNGOs and local communities, donors and the private sector by providing objective and timely information on natural resource allocation and use. REM is not a lobbying organisation and has no political agenda, but is pro-active in researching and presenting the issue of governance and transparency during project implementation. (Full article...)
Girard form class is a form quotient calculated as the ratio of diameter inside bark at the top of the first 16 foot log to the diameter outside bark at breast height (DBH). Its purpose is to estimate board-foot volume of whole trees from measurement of DBH, estimation of the number of logs, and estimation of the taper of the first log, based on the general relationships identified between the taper of the first log and the taper of subsequent logs. Girard form class is the primary expression of tree form in the United States.
To allow for log trimming and a 1-foot stump height the diameter inside bark is measured at 17.3 feet above the ground. The closer the form class value to 100 the closer the log resembles a cylinder, where a value of 100 means the log is very nearly a cylinder.
Volume tables using Girard form class are composite tables and are created independently of tree species. The volume tables may be corrected where systemic errors are identified, and modified GFC volume tables are available for conifers in the northeast, outside of the original study area.
Girard form class assumes a large minimum merchantable top diameter (40% for large trees, such that a 40” tree would have a top diameter of 16”), and the tables will overestimate if additional logs are counted to smaller diameters commonly utilized by modern mills.
To calculate GFC, you need several things: DIB (Diameter inside bark) @ 17.3', DOB (diameter outside bark) @ 17.3', DBH (diameter @ 4.5'), and [single] bark thickness (which will be used to calculate double bark thickness).
Example:
Bark Thickness = .56"
Double Bark Thickness = 1.12"
DOB @ 17.3' = 18.2"
DIB @ 17.3' = 17.08" (18.2" - 1.12")
DBH = 21.9"
((17.08")/(21.9")) * 100 = 77.99%, therefore the volume table for GFC 78 will be used as the basis of estimating volume (Full article...)
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Continuous cover forestry (commonly referred to as "CCF") is an approach to the sustainable management of forests whereby forest stands are maintained in a permanently irregular structure, which is created and sustained through the selection and harvesting of individual trees. The term "continuous cover forestry" does not equate exactly to any one particular silvicultural system, but is typified by selection systems. For example, coppice with standards and Reiniger's target diameter harvesting are also continuous cover forestry. Different existing forest stands may require different silvicultural interventions to achieve a continuously productive irregular structure. Crucially, clearcutting and other rotational forest management systems are avoided. (Full article...)
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In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are usable as lumber or plants above a specified height. In wider definitions, the taller palms, tree ferns, bananas, and bamboos are also trees.
Trees are not a monophyletic taxonomic group but consist of a wide variety of plant species that have independently evolved a trunk and branches as a way to tower above other plants to compete for sunlight. The majority of tree species are angiosperms or hardwoods; of the rest, many are gymnosperms or softwoods. Trees tend to be long-lived, some reaching several thousand years old. Trees have been in existence for 370 million years. It is estimated that there are around three trillion mature trees in the world.
A tree typically has many secondary branches supported clear of the ground by the trunk, which typically contains woody tissue for strength, and vascular tissue to carry materials from one part of the tree to another. For most trees it is surrounded by a layer of bark which serves as a protective barrier. Below the ground, the roots branch and spread out widely; they serve to anchor the tree and extract moisture and nutrients from the soil. Above ground, the branches divide into smaller branches and shoots. The shoots typically bear leaves, which capture light energy and convert it into sugars by photosynthesis, providing the food for the tree's growth and development.
Trees usually reproduce using seeds. Flowers and fruit may be present, but some trees, such as conifers, instead have pollen cones and seed cones. Palms, bananas, and bamboos also produce seeds, but tree ferns produce spores instead.
Trees play a significant role in reducing erosion and moderating the climate. They remove carbon dioxide from the atmosphere and store large quantities of carbon in their tissues. Trees and forests provide a habitat for many species of animals and plants. Tropical rainforests are among the most biodiverse habitats in the world. Trees provide shade and shelter, timber for construction, fuel for cooking and heating, and fruit for food as well as having many other uses. In much of the world, forests are shrinking as trees are cleared to increase the amount of land available for agriculture. Because of their longevity and usefulness, trees have always been revered, with sacred groves in various cultures, and they play a role in many of the world's mythologies. (Full article...)
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Tree planting is the process of transplanting tree seedlings, generally for forestry, land reclamation, or landscaping purposes. It differs from the transplantation of larger trees in arboriculture and from the lower-cost but slower and less reliable distribution of tree seeds. Trees contribute to their environment over long periods of time by providing oxygen, improving air quality, climate amelioration, conserving water, preserving soil, and supporting wildlife. During the process of photosynthesis, trees take in carbon dioxide and produce the oxygen we breathe.
In silviculture, the activity is known as "reforestation", or "afforestation," depending on whether the area being planted has recently been forested or not. It involves planting seedlings over an area of land where the forest has been harvested or damaged by fire, disease, or human activity. Tree planting is carried out in many different parts of the world, and strategies may differ widely across nations and regions and among individual reforestation companies. Tree planting is grounded in forest science and, if performed properly, can result in the successful regeneration of a deforested area. Reforestation is the commercial logging industry's answer to the large-scale destruction of old-growth forests, but a planted forest rarely replicates the biodiversity and complexity of a natural forest.
Because trees remove carbon dioxide from the air as they grow, tree planting can be used to help limit climate change. Desert greening projects are also motivated by improved biodiversity and reclamation of natural water systems, as well as improved economic and social welfare due to an increased number of jobs in farming and forestry. (Full article...)
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Dendrology (Ancient Greek: δένδρον, dendron, "tree"; and Ancient Greek: -λογία, -logia, science of or study of) or xylology (Ancient Greek: ξύλον, ksulon, "wood") is the science and study of woody plants (trees, shrubs, and lianas), specifically, their taxonomic classifications. There is no sharp boundary between plant taxonomy and dendrology; woody plants not only belong to many different plant families, but these families may be made up of both woody and non-woody members. Some families include only a few woody species. Dendrology, as a discipline of industrial forestry, tends to focus on identification of economically useful woody plants and their taxonomic interrelationships. As an academic course of study, dendrology will include all woody plants, native and non-native, that occur in a region. A related discipline is the study of sylvics, which focuses on the autecology of genera and species.
In the past, dendrology included the study of the natural history of woody species in specific regions, but this aspect is now considered part of ecology. The field also plays a role in conserving rare or endangered species. (Full article...)
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The Rainforest Alliance is an international non-governmental organization (NGO) with staff in more than 20 countries and operations in more than 70 countries. It was founded in 1987 by Daniel Katz, an American environmental activist, who serves as the chair of the board of directors. The NGO states that its mission is "to create a more sustainable world by using social and market forces to protect nature and improve the lives of farmers and forest communities." Its work includes the provision of an environmental certification for sustainability in agriculture. In parallel to its certification program, the Rainforest Alliance develops and implements long-term conservation and community development programs in a number of critically important tropical landscapes where commodity production threatens ecosystem health and the well-being of rural communities.
The Rainforest Alliance is a product-oriented multistakeholder governance group combining the interests of companies, farmers, foresters, communities, and consumers to produce sustainable and harmonious goods. (Full article...)
Many tools like remote sensing, GIS and photogrammetry modelling have been developed to improve forest inventory and management planning. Since 1953, the volume of standing trees in the United States has increased by 90% due to sustainable forest management. (Full article...)
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The idea of an international organization for food and agriculture emerged in the late 19th and early 20th century, advanced primarily by Polish-born American agriculturalist and activist David Lubin. In May–June 1905, an international conference was held in Rome, Italy, which led to the creation of the International Institute of Agriculture (IIA) by the King of Italy, Victor Emmanuel III.
The IIA was the first intergovernmental organization to deal with the problems and challenges of agriculture on a global scale. It worked primarily to collect, compile, and publish data on agriculture, ranging from output statistics to a catalog of crop diseases. Among its achievements was the publication of the first agricultural census in 1930.
World War II effectively ended the IIA. During the war, in 1943, United States President Franklin D. Roosevelt called a League of Nations Conference on Food and Agriculture, which brought representatives from forty-four governments to The Omni Homestead Resort in Hot Springs, Virginia, from 18 May to 3 June to attend the Hot Springs Conference. The main impetus for the conference was the British-born Australian economist Frank L. McDougall, who since 1935 had advocated for an international forum to address hunger and malnutrition.
The Conference ended with a commitment to establish a permanent organization for food and agriculture, which was achieved on 16 October 1945 in Quebec City, Canada, following the Constitution of the Food and Agriculture Organization. The first session of the FAO Conference began the same day in the Château Frontenac in Quebec City and ended on 1 November 1945. This was led by Sir John Boyd Orr where his work on ending world hunger and creation of FAO resulted in him winning the Nobel Peace Prize in 1949.
After the war, the IIA was officially dissolved by resolution of its Permanent Committee on 27 February 1948. Its functions, facilities, and mandate were then transferred to the newly established FAO, which maintained its headquarters in Rome.
The FAO's initial functions supported agricultural and nutrition research and provided technical assistance to member countries to boost production in agriculture, fishery, and forestry. Beginning in the 1960s, it focused on efforts to develop high-yield strains of grain, eliminate protein deficiency, promote rural employment, and increase agricultural exports. The FAO recognized the decrease of these resources as an urgent problem in 1961 and created a joint collaboration with the International Biological Program (IBP) in 1967. To that end, it joined the UN General Assembly in creating the UN World Food Programme, the largest humanitarian organization addressing hunger and promoting food security.
The FAO launched what would become the FAO Money and Medals Programme (MMP) in 1968. FAO issued collector art medals in various series to bring attention to FAO's goals and missions. This program was responsible for over a hundred medal designs issued to the collecting public. A thirtieth anniversary medal of the MMP was issued in 1998.
In 1974, in response to famine in Africa, the FAO convened the first World Food Summit to address widespread hunger, malnutrition, and food insecurity. The meeting resulted in a proclamation that "every man, woman, and child has the inalienable right to be free from hunger and malnutrition to develop their physical and mental faculties" and a global commitment to eradicate these issues within a decade. A subsequent summit in 1996 addressed the shortcomings in achieving this goal while establishing a strategic plan for eliminating hunger and malnutrition into the 21st century.
Every year, FAO publishes a number of major 'State of the World' reports related to food, agriculture, forestry, fisheries and natural resources. (Full article...)
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Underwater logging is the process of logging trees from underwater forests. When artificial reservoirs and dams are built, large areas of forest are often inundated; although the trees die, the wood is often preserved. The trees can then be felled using special underwater machinery and floated up to the surface. One such machine is the sawfish harvester. There is an ongoing debate to determine whether or not underwater logging is a sustainable practice and if it is more environmentally sustainable than traditional logging.
Underwater logging has been introduced in select locations around the world, including Ghana's Lake Volta, the largest reservoir by surface area in the world.
A related form of logging consists of salvaging logs which loggers have abandoned after they became waterlogged and sank. This activity can be quite profitable, since the prime "targets" are decades-old trees of a size and species difficult or impossible to find in their natural habitat. (Full article...)
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Forest Peoples Programme (FPP) advocates an alternative vision of how forests should be managed and controlled, based on respect for the rights of the people who know them best. FPP works with forest peoples in South America, Africa, and Asia, to help them secure their rights, build up their own organisations and negotiate with governments and companies as to how economic development and conservation are the best achieved on their lands.
Forests cover 31% of total land area of the planet. Of that, 12% are designated for the conservation of biological diversity and nearly all are inhabited. Many of the peoples, who live in and have customary rights to their forests, have developed ways of life and traditional knowledge that are attuned to their forest environments. Yet, forest policies commonly treat forests as empty lands controlled by the state and available for ‘development’ – colonisation, logging, plantations, dams, mines, oil wells, gas pipelines and agribusiness. These encroachments often force forest peoples out of their forest homes. Many conservation schemes to establish wilderness reserves also deny forest peoples’ rights. (Full article...)
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Cork is an impermeablebuoyant material. It is the phellem layer of bark tissue which is harvested for commercial use primarily from Quercus suber (the cork oak), which is native to southwest Europe and northwest Africa. Cork is composed of suberin, a hydrophobic substance. Because of its impermeable, buoyant, elastic, and fire retardant properties, it is used in a variety of products, the most common of which is wine stoppers.
The montado landscape of Portugal produces approximately half of the cork harvested annually worldwide, with Corticeira Amorim being the leading company in the industry. Cork was examined microscopically by Robert Hooke, which led to his discovery and naming of the cell.
Turpentine (which is also called spirit of turpentine, oil of turpentine, terebenthine, terebenthene, terebinthine and, colloquially, turps) is a fluid obtained by the distillation of resin harvested from living trees, mainly pines. Principally used as a specialized solvent, it is also a source of material for organic syntheses.
In current usage, the term remote sensing generally refers to the use of satellite- or aircraft-based sensor technologies to detect and classify objects on Earth. It includes the surface and the atmosphere and oceans, based on propagated signals (e.g. electromagnetic radiation). It may be split into "active" remote sensing (when a signal is emitted by a satellite or aircraft to the object and its reflection is detected by the sensor) and "passive" remote sensing (when the reflection of sunlight is detected by the sensor). (Full article...)
Global annual deforestation is estimated to total 13.7 million hectares a year, similar to the area of Greece. Half of the area experiencing deforestation consists of new forests or forest growth. In addition to direct human-induced deforestation, growing forests have also been affected by climate change. The Kyoto Protocol includes an agreement to prevent deforestation, but does not stipulate actions to fulfil it.
The rate of global tree cover loss has approximately doubled since 2001, to an annual loss approaching an area the size of Italy.
The log scaler is an occupation in the timber industry. The Log Scaler measures the cut trees to determine the scale (volume) and quality (grade) of the wood to be used for manufacturing. When logs are sold, in order to determine the basis for a sale price in a standard way, the logs are "scaled" which means they are measured, identified as to species, and deductions for defects assigned to produce a net volume of merchantable wood. There are several different scales or rules that are used to determine the volume of wood. Scribner Decimal C rule is based on diagrams of circles that show the number of boards that will be utilized from the diameters of logs. The cubic rule, often called Metric in Canada, determines the cubic volume of the log material. The logs are recorded as gross scale (actual log measurements, length and diameter) and net scale (volume after deductions for defects are taken out). This occupation is usually performed by a third party organization qualified to "scale" government timber. Since internal defects are determined by external indications, scaling is not an exact science and is subject to interpretation of log scaling rules. The log scaler is subject to random "check scales" in which another scaler rescales exactly the same logs and the results are compared. The log scaler must be within + or - 1% of the gross scale and + or - 2% of the net scale to keep their certification to scale. The scale is used for payment, quality control and inventory purposes. (Full article...)
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One of Bhutan's significant natural resources in the late twentieth century was its rich forests and natural vegetation. Bhutan's location in the eastern Himalayas, with its subtropical plains and alpine terrain, gives it more rainfall than its neighbors to the west, a factor greatly facilitating forest growth. The forests contain numerous deciduous and evergreen species, ranging from tropical hardwoods to predominantly oak and pine forests. (Full article...)
Interception refers to precipitation that does not reach the soil, but is instead intercepted by the leaves, branches of plants and the forest floor. It occurs in the canopy (i.e. canopy interception), and in the forest floor or litter layer (i.e. forest floor interception ). Because of evaporation, interception of liquid water generally leads to loss of that precipitation for the drainage basin, except for cases such as fog interception, but increase flood protection dramatically, Alila et al., (2009). Intercepted snowfall does not result in any notable amount of evaporation, and most of the snow falls off the tree by wind or melts. However, intercepted snow can more easily drift with the wind, out of the watershed. Conifers have a greater interception capacity than hardwoods. Their needles gives them more surface area for droplets to adhere to, and they have foliage in spring and fall, therefore interception also depends on the type of vegetation in a wooded area.
Mitscherlich in 1971 calculated the water storage potential as interception values for different species and stand densities. A storm event might produce 50 – 100 mm of rainfall and 4 mm might be the maximum intercepted in this way. Grah and Wilson in 1944 did sprinkling experiments where they watered plants to see how much of the intercepted is kept after watering stops.
Trees like Norway maple and a small-leaved lime have an interception of approximately 38% of the gross precipitation in temperate climate.
The interception depends on the leaf area index and what kind of leaves they are.
Energy forestry is a form of forestry in which a fast-growing species of tree or woody shrub is grown specifically to provide biomass or biofuel for heating or power generation.
Forests have always been important for economic development and environmental maintenance. In 1890, the International Agriculture and Forestry Congress in Vienna, Austria, proposed to establish a "central organ" for applied forest research in the European countries. As a consequence, the “International Union of Forest Experiment Organizations” was founded in Eberswalde, Germany, in 1892. Originally, only Austria, Germany and Switzerland agreed that their forest experiment stations would join the Union. By the beginning of World War I, stations from 22 countries, including USA, Canada and Japan, had become members.
During World War I international cooperation stopped, as did forest research in many of the countries involved in the war. The Union only fully resumed its activities in 1929 when the new name “International Union of Forestry Research Organizations” was adopted. In the years to follow, the organization lost its Central European character as more representatives from Africa, Asia and the Americas joined.
World War II reduced the activities of the Union to a minimum. Cooperation continued only between individuals, and not on an institutional basis. In 1949 the newly established Food and Agriculture Organization of the United Nations (FAO) declared its readiness to make available to IUFRO a secretariat at FAO’s own Headquarters in Rome. IUFRO has played a role in establishing standards and harmonizing field investigations in forest research. In 1903, the Union initiated international forestry bibliographies that did not exist earlier. Gradually the development led to the well-known Oxford System of Decimal Classification (ODe) for Forestry in the 1950s
The 1950s and 1960s were a period of steady growth. The XV IUFRO World Congress in Gainesville, USA, in 1971 was the first Congress held outside Europe. For the first time, it was referred to as a “World Congress,” and a Congress title was introduced: “The Role of Research in the Intensification of Forestry Practices and Activities.”
In the 1980s, IUFRO started to increasingly address forest-related social, economic, and ecological problems of global importance. The XVIII World Congress held in Ljubljana, Yugoslavia, in 1986 was the first to take place in Eastern Europe.
Since the 1990s the focus of the community of forest policymakers, economists and managers has changed. This is as societal expectations regarding forests broadened to include enhanced production of forest goods, social benefits, and environmental services through sustainable management of trees and forests. IUFRO responded to these challenges by adapting its scientific structure, expanding strategic partnerships and engaging more at the science/policy interface.
The XXI IUFRO World Congress in Kuala Lumpur, Malaysia, in 2000 was the first IUFRO World Congress to be held in a developing country. In 2000 the name of the Union was changed once more into “International Union of Forest Research Organizations”. The year 2000 also marked the first time in IUFRO´s history that gender issues were formally addressed. Over the last ten years, IUFRO undertook efforts to expand the scope of work beyond ‘traditional’ sectoral and disciplinary boundaries. At the 125th Anniversary Congress in 2017 in Freiburg, Germany, the slogan “Interconnecting Forests, Science and People” was adopted as part of the logo. (Full article...)
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Lumberjack is a mostly North American term for workers in the logging industry who perform the initial harvesting and transport of trees. The term usually refers to loggers in the era before 1945 in the United States, when trees were felled using hand tools and dragged by oxen to rivers.
The work was difficult, dangerous, intermittent, low-paying, and involved living in primitive conditions. However, the men built a traditional culture that celebrated strength, masculinity, confrontation with danger, and resistance to modernization. (Full article...)
The broadfin shark (Lamiopsis temminckii) is a tropical whaler shark, characterized by the broad shape of its pectoral fins. They are classified as requiem sharks of the family Carcharhinidae. This is one of two species in the genus Lamiopsis, the other being the Borneo broadfin shark (Lamiopsis tephrodes). The broadfin shark is native to the northern Indian Ocean, and is found close to shore. Its current status according to the IUCN is endangered. (Full article...)
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The dumb gulper shark (Centrophorus harrissoni) is a rare and endangered deepwater dogfish, found along the east coast of Australia and in isolated spots north and west of New Zealand. It is also known as the dumb shark, Harrison's deep-sea dogfish, or Harrison's dogfish. (Full article...)
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The blacktip reef shark (Carcharhinus melanopterus) is a species of requiem shark, in the family Carcharhinidae, which can be easily identified by the prominent black tips on its fins (especially on the first dorsal fin and its caudal fin). Among the most abundant sharks inhabiting the tropicalcoral reefs of the Indian and Pacific Oceans, this species prefers shallow, inshore waters. Its exposed first dorsal fin is a common sight in the region. The blacktip reef shark is usually found over reef ledges and sandy flats, though it has also been known to enter brackish and freshwater environments. It typically attains a length of 1.6 m (5.2 ft). Like other sharks, the females are larger than the males.
The blacktip reef shark has extremely small home ranges and exhibits strong site fidelity, remaining within the same local area for up to several years at a time. It is an active predator of small bony fish, cephalopods, and crustaceans, and has also been known to feed on sea snakes and seabirds. Accounts of the blacktip reef shark's life history have been variable and sometimes contradictory, in part reflecting geographical differences within the species. Like other members of its family, this shark is viviparous, with females giving birth to two to five young on a biennial, annual, or possibly biannual cycle. Reports of the gestation period range from 7–9, through 10–11, to possibly 16 months. Mating is preceded by the male following closely behind the female, likely attracted by her chemical signals. Newborn sharks are found further inshore and in shallower water than adults, frequently roaming in large groups over areas flooded by high tide.
Timid and skittish, the blacktip reef shark is difficult to approach and seldom poses a danger to humans unless roused by food. However, people wading through shallow water are at risk of having their legs mistakenly bitten. This shark is used for its meat, fins, and liver oil, but is not considered to be a commercially significant species. The International Union for Conservation of Nature has assessed the blacktip reef shark as Vulnerable. Although the species as a whole remains widespread and relatively common, overfishing of this slow-reproducing shark has led to its decline at a number of locales. (Full article...)
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The Indonesian whaler shark (Carcharhinus tjutjot), is a species of requiem shark belonging to the familyCarcharhinidae. Until recently, it was thought to be a junior synonym of the whitecheek shark (C. dussumieri). The Indonesian whaler shark, along with the family Carcharhinidae, is a key economic group in global fisheries including commercial and small-scale fisheries within the Indo-Pacific region. Common spawning and nursery areas overlap with commercial fishing grounds and it is often caught as bycatch which has caused it to be listed as a vulnerable species. (Full article...)
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Ginglymostoma unami, also known as the Pacific nurse shark is a nurse shark of the family Ginglymostomatidae. It is found in southeastern coast of Baja California, Mexico to Costa Rica including Gulf of California. It is 2.8 meters long. This species differs from Ginglymostoma cirratum between posterior end of the second dorsal fin and the beginning of the caudal lobe, both being shorter; the new species also differs by the position of the insertion of the first dorsal fin with regard to the pelvic fins and in the form and number of keels on the dermal denticles and teethmorphology. The Ginglymostoma unami was previously recognized as G.cirratum exhibiting a divided distribution of a species in the northern half of the Atlantic Ocean. However, that species is now considered to be restricted to just the Atlantic Ocean. (Full article...)
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Scyliorhinus meadi, the blotched catshark, is a little-known species of catshark, and part of the family Scyliorhinidae, found in the western central Atlantic Ocean. It inhabits banks of deep-sea coral at depths of 329–548 m (1,079–1,798 ft), feeding on cephalopods, shrimp, and bony fishes. This species can be identified by its wide body and head, and the dark saddle-like markings on its back. It also has small spots that fluoresce yellow under a blue light. Adult blotched catsharks have not been observed; the largest immature specimen is 49 cm (19 in) long. Like other catsharks, it is believed to be oviparous. This species is not dangerous to humans and has no commercial significance. (Full article...)
George Albert BoulengerFRS (19 October 1858 – 23 November 1937) was a Belgian-British zoologist who described and gave scientific names to over 2,000 new animal species, chiefly fish, reptiles, and amphibians. Boulenger was also an active botanist during the last 30 years of his life, especially in the study of roses. (Full article...)
The finetooth shark (Carcharhinus isodon) is a species of requiem shark, in the family Carcharhinidae, found in the western Atlantic Ocean, from North Carolina to Brazil. It forms large schools in shallow, coastal waters, and migrates seasonally following warm water. A relatively small, slender-bodied shark, the finetooth shark can be identified by its needle-like teeth, dark blue-gray dorsal coloration, and long gill slits. It attains a maximum length of 1.9 m (6.2 ft). The diet of this species consists primarily of small bony fishes, in particular menhaden. Like other members of its family, it is viviparous with females giving birth to two to six pups in estuarine nursery areas every other year.
Valued for its meat, the finetooth shark forms an important component of the commercialgillnet shark fishery operating off the southeastern United States. Population assessments suggest that this fishery does not currently pose a threat to U.S. populations of the species. This shark is not known to pose a danger to humans, though it snaps vigorously when captured and should be handled with caution. (Full article...)
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The basking shark (Cetorhinus maximus) is the second-largest living shark and fish, after the whale shark. It is one of three plankton-eating shark species, along with the whale shark and megamouth shark. Typically, basking sharks reach 7.9 m (26 ft) in length. It is usually greyish-brown, with mottled skin, with the inside of the mouth being white in colour. The caudal fin has a strong lateral keel and a crescent shape. Other common names include bone shark, elephant shark, sailfish, and sunfish. In Orkney, it is called hoe-mother (contracted homer), meaning "the mother of the picked dogfish".
The basking shark is a cosmopolitanmigratory species found in all the world's temperate oceans. A slow-moving filter feeder, its common name derives from its habit of feeding at the surface, appearing to be basking in the warmer water there. It has anatomical adaptations for filter-feeding, such as a greatly enlarged mouth and highly developed gill rakers. Its snout is conical, and the gill slits extend around the top and bottom of its head. The gill rakers, dark and bristle-like, are used to catch plankton as water filters through the mouth and over the gills. The teeth are numerous and very small and often number 100 per row. The teeth have a single conical cusp, are curved backwards and are the same on both the upper and lower jaws. This species has the smallest weight-for-weight brain size of any shark, reflecting its relatively passive lifestyle.
Basking sharks have been shown from satellite tracking to overwinter in both continental shelf (less than 200 m or 660 ft) and deeper waters. They may be found in either small shoals or alone. Despite their large size and threatening appearance, basking sharks are not aggressive and are harmless to humans.
The Indonesian whaler shark (Carcharhinus tjutjot), is a species of requiem shark belonging to the familyCarcharhinidae. Until recently, it was thought to be a junior synonym of the whitecheek shark (C. dussumieri). The Indonesian whaler shark, along with the family Carcharhinidae, is a key economic group in global fisheries including commercial and small-scale fisheries within the Indo-Pacific region. Common spawning and nursery areas overlap with commercial fishing grounds and it is often caught as bycatch which has caused it to be listed as a vulnerable species. (Full article...)
The brown shyshark or plain happy (Haploblepharus fuscus) is a species of catshark, part of the family Scyliorhinidae. It is endemic to the shallow, coastal waters of South Africa from west of Cape Agulhas to KwaZulu-Natal. This benthic species is usually found over sandy or rocky bottoms. Measuring up to 73 cm (29 in) long, the brown shyshark is stoutly built, with a broad, flattened head and rounded snout. Unlike other shysharks, the brown shyshark has a plain brown color, though some individuals have faint "saddle" markings or light or dark spots. When threatened, this shark curls into a circle with its tail over its eyes, which is the origin of the name "shyshark". It feeds on bony fishes and lobsters, and is oviparous with females laying pairs of egg capsules. The International Union for Conservation of Nature (IUCN) has assessed this harmless species as Vulnerable. It is of no commercial or recreational interest, but its limited distribution makes its entire population vulnerable to increases in fishing pressure or habitat degradation. (Full article...)
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The Bali catshark (Atelomycterus baliensis) is a species of catshark, belonging to the familyScyliorhinidae, found only off the Indonesian island of Bali. It can grow up to 47 cm (19 in). Atelomycterus baliensis inhabits the deep coastal waters of Bali, Indonesia, feeding on small fish and invertebrates. (Full article...)
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The genus Eridacnis, the ribbontail catsharks, is a small genus of fin-back catsharks in the family Proscylliidae. It currently consists of the following species:
The spotted wobbegong (Orectolobus maculatus) is a carpet shark in the familyOrectolobidae, endemic to Australia. It is a large, robust species, typically reaching 150–180 centimetres (59–71 in) in length. Coloured green, yellow, or brown, it has distinctive O-shaped spots throughout its body. It is nocturnal, resting at day and feeding on fish and invertebrates at night. An ovoviviparous species, the spotted wobbegong gives birth in the spring, during which time males can act aggressively towards other males and females. It has been known to bite humans, sometimes unprovoked, which can produce severe wounds. The species is fished commercially in Australia, but it is not severely threatened. It is listed as a least-concern species on the IUCN Red List. (Full article...)
The mandarin dogfish (Cirrhigaleus barbifer) is a dogfish, a member of the familySqualidae in the order Squaliformes. It is found at depths of 140–650 metres (460–2,130 ft) off southern Japan, Taiwan, and Indonesia (Bali and Lombok). Populations off Australia and New Zealand were formerly included in this species, but in 2007 these were assigned to a new species, the southern mandarin dogfish. It is not clear which of these species is involved in other populations from the tropical West Pacific.
The Pacific sharpnose shark (Rhizoprionodon longurio) often migrates along the Pacific coast of Mexico. They are most commonly caught in the artisanal fishery of Mazatlán. When a large sample of Pacific sharpnose sharks were observed scientists concluded that this type of shark was a "viviparous shark of small size which is born at an average length of 31 cm." Their gestation period is between ten and eleven months.
There was found to be no statistical relationship between the number of embryos to the average length as a result of scientific research. Specialists David Corro, Leonardo Castillo Geniz and J. Fernando Marquez-Farias, found that the sex ratio of this specific Shark is one to one with the average number of embryos per female, being around 7.4. (Full article...)
Parascylliidae, or the collared carpet sharks, is a family of sharks in the order Orectolobiformes, which are only found in shallow waters of the western Pacific. The family Parascylliidae contains two genera, Cirrhoscyllium and Parascyllium. They are relatively small sharks, with the largest species reaching no more than 91.0 cm in adult length. They have elongated, slender bodies, cat-like eyes, and barbels behind their chins. They feed on small fish and invertebrates. (Full article...)
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The longnose sawtail catshark (Galeus longirostris) is a little-known species of catshark, part of the familyScyliorhinidae, found off the northwestern Pacific islands of Amami Ōshima, Ogasawara, and Izu at depths of 350–550 m (1,150–1,800 ft). Reaching a length of 80 cm (31 in), it is characterized by a long flattened snout, a long space between the pelvic and anal fins, and a crest of enlarged dermal denticles along the dorsal caudal fin edge. Adults are plain dark gray above, while juveniles have a few faint dark saddles on the back and tail. (Full article...)
Oxynotus caribbaeus is thought to be a slow-moving predator of small benthic organisms. Not much is known about the lifecycle of this species, but it is being observed in its natural environment lately. This species is an uncommon bycatch of bottom trawls. (Full article...)
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The Lamniformes (/ˈlæmnɪfɔːrmiːz/, from Greek lamna "fish of prey") are an order of sharks commonly known as mackerel sharks (which may also refer specifically to the family Lamnidae). It includes some of the most familiar species of sharks, such as the great white, as well as more unusual representatives, such as the goblin shark and megamouth shark.
Members of the order are distinguished by possessing two dorsal fins, an anal fin, five gill slits, eyes without nictitating membranes, and a mouth extending behind the eyes. Species in two families of Lamniformes – Lamnidae and Alopiidae – are distinguished for maintaining a higher body temperature than the surrounding waters.
Members of the group include macropredators, generally of medium-large size, including the largest macropredatory shark ever, the extinct Otodus megalodon, as well as large planktivores.
The small ~1 metre (3.3 ft) long carpet shark-like Palaeocarcharias, known from the Middle and Late Jurassic, shares the distinctive tooth histology of most lamniform sharks, which lack orthodentine, and is thus considered either the oldest lamniform or a sister group to all lamniforms. Lamniformes underwent a major adaptive radiation during the Cretaceous and became prominent elements of oceanic ecosystems. They reached their highest diversity during the Late Cretaceous, but severely declined during the K-Pg extinction, before rebounding to a high but lower diversity peak during the Paleogene. Lamniformes have severely declined over the last 20 million years, with only 15 species alive today, compared to over 290 extant species in the Carcharhiniformes, which have evolved into medium and large body sizes during the same timeframe. The causes of the decline are uncertain, but are likely to have involved both biotic factors like competition and non-biotic factors like temperature and sea level. (Full article...)
The splendid lanternshark (Etmopterus splendidus) is a shark of the familyEtmopteridae found in the western Pacific at depths between 120 and 210 m. Through the classification of Etmopterus species into several clades based on the positioning of their bioluminescent photophores, the splendid lanternshark can be considered a member of the Etmopterus pusillus clade.
The smooth hammerhead (Sphyrna zygaena) is a species of hammerhead shark, and part of the family Sphyrnidae. This species is named "smooth hammerhead" because of the distinctive shape of the head, which is flattened and laterally extended into a hammer shape (called the "cephalofoil"), without an indentation in the middle of the front margin (hence "smooth"). Unlike other hammerheads, this species prefers temperate waters and occurs worldwide at medium latitudes. In the summer, these sharks migrate towards the poles following cool water masses, sometimes forming schools numbering in the hundreds to thousands.
The second-largest hammerhead shark after the great hammerhead shark, the smooth hammerhead can measure up to 5 m (16 ft) long. It is an active predator that takes a wide variety of bony fishes and invertebrates, with larger individuals also feeding on sharks and rays. As in the rest of its family, this shark is viviparous and gives birth to litters of 20–40 pups. A relatively common shark, it is captured, intentionally or otherwise, by many commercial fisheries throughout its range; its fins are extremely valuable for use in shark fin soup. This shark is potentially dangerous and has likely been responsible for a few attacks on humans, though it is less likely to encounter swimmers than other large hammerhead species due to its temperate habitat. (Full article...)
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Bythaelurus is a genus of deep-water catsharks and part of the familyScyliorhinidae. The genus Bythaelurus Compagno 1988 was first described as a subgenus of Halaelurus Gill 1862 based on several morphological characteristics including a soft body with thin skin, a bluntly rounded snout without a pointed, knob-like tip, and eyes not noticeably elevated on the dorsal surface of the head. Members of this genus are generally found in deep water and have more somber body coloration. (Full article...)
The cloudy catshark (Scyliorhinus torazame) is a common species of catshark, belonging to the familyScyliorhinidae. It is a bottom-dweller that inhabits rocky reefs in the northwestern Pacific Ocean, from the shore to a depth of 320 m (1,050 ft). Growing up to 50 cm (20 in) long, this small, slim shark has a narrow head with a short blunt snout, no grooves between the nostrils and mouth, and furrows on the lower but not the upper jaw. It is also characterized by extremely rough skin and coloration consisting of a series of dark brown saddles along its back and tail, along with various darker and lighter spots in larger individuals.
One of the smaller hammerheads, the scoophead measures 150 cm long; adult males measure 90 cm long and adult females 100–133 cm. It is distinguished by its moderately broad, mallet-shaped head (22–33% as wide as the body is long). The forward margin of the head is arched, with weak medial and lateral indentations and no prenarial grooves, traits that this species shares with the scalloped bonnethead (Sphyrna corona). It is distinguished from the scalloped bonnethead by its shorter snout, broadly arched mouth, and deeply concave anal fin. The first dorsal fin is moderately falchate, and the second dorsal fin is as tall as the anal fin. The pelvic fins are not falchate, with a straight to moderately concave rear margin. Its coloration is grey-brown above, light below, with no fin markings.
Off the coast of Trinidad, the scoophead coexists with two other small hammerheads, the bonnethead (Sphyrna tiburo) and the golden hammerhead (S. tudes). These species avoid competition by diet and habitat differences; the scoophead feeds on small elasmobranchs, octopus, squid, and flounders. Like other hammerheads, the scoophead is viviparous, with the pups measuring 34 cm or less at birth. It is taken with bottom longlines, gillnets, and hook and line throughout its range. It is caught commercially and sold as fresh fish or turned into fishmeal. The scoophead is also a common bycatch of the gillnet mackerelfishery off Trinidad. (Full article...)
The bramble shark (Echinorhinus brucus) is one of the two species of sharks in the familyEchinorhinidae. Aside from the eastern Pacific Ocean, it is found in tropical and temperate waters worldwide. This rarely encountered shark swims close to the bottom of the seafloor, typically at depths of 400–900 m (1,300–3,000 ft), though it may enter much shallower water. The bramble shark has a stout body with two small dorsal fins positioned far back and no anal fin. It can be readily identified by the large, thorn-like dermal denticles scattered over its body, some of which may be fused together. It is purplish brown or black in color and grows up to 3.1 m (10 ft) long.
The diet of the bramble shark includes smaller sharks, bony fishes, and crabs, which this slow-moving species may capture via suction. It is aplacental viviparous, with females producing litters of 15–52 pups. Harmless to humans, it is an occasional bycatch of commercial and recreational fishers, and may be used for fishmeal and liver oil. Its population has declined substantially in the northeastern Atlantic since the 18th and 19th centuries, likely because of overfishing. (Full article...)
While these common names may apply to several species, Squalus acanthias is distinguished by two spines (one anterior to each dorsal fin) and no anal fin. It lives in shallow waters and further offshore in most parts of the world, especially in temperate waters. Those in the northern Pacific Ocean were reevaluated in 2010 and found to constitute a separate species, now called the Pacific spiny dogfish (Squalus suckleyi). (Full article...)
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The whale shark (Rhincodon typus) is a slow-moving, filter-feedingcarpet shark and the largest known extantfishspecies. The largest confirmed individual had a length of 18.8 m (61.7 ft). The whale shark holds many records for size in the animal kingdom, most notably being by far the most massive living non-cetacean animal. It is the sole member of the genus Rhincodon and the only extant member of the family Rhincodontidae, which belongs to the subclass Elasmobranchii in the class Chondrichthyes. Before 1984 it was classified as Rhiniodon into Rhinodontidae.
Whale sharks inhabit the open waters of all tropical oceans. They are rarely found in water below 21 °C (70 °F). Whale sharks' lifespans are estimated to be between 80 and 130 years, based on studies of their vertebral growth bands and the growth rates of free-swimming sharks. Whale sharks have very large mouths and are filter feeders, which is a feeding mode that occurs in only two other sharks, the megamouth shark and the basking shark. They feed almost exclusively on plankton and small fishes and pose no threat to humans.
The species was distinguished in April 1828 after the harpooning of a 4.6 m (15 ft) specimen in Table Bay, South Africa. Andrew Smith, a military doctor associated with British troops stationed in Cape Town, described it the following year. The name "whale shark" refers to the animal's appearance and large size; it is a fish, not a mammal, and (like all sharks) is not closely related to whales. In addition, its filter feeding habits are similar to baleen whales. (Full article...)
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The Pacific sharpnose shark (Rhizoprionodon longurio) often migrates along the Pacific coast of Mexico. They are most commonly caught in the artisanal fishery of Mazatlán. When a large sample of Pacific sharpnose sharks were observed scientists concluded that this type of shark was a "viviparous shark of small size which is born at an average length of 31 cm." Their gestation period is between ten and eleven months.
There was found to be no statistical relationship between the number of embryos to the average length as a result of scientific research. Specialists David Corro, Leonardo Castillo Geniz and J. Fernando Marquez-Farias, found that the sex ratio of this specific Shark is one to one with the average number of embryos per female, being around 7.4. (Full article...)
The Bahamas sawshark is found on continental and insular slopes. Its reproduction is ovoviviparous.
Pristiophorus schroederi is the first member of the sawsharks (family Pristiophoridae) described from the western hemisphere. Like its family members, it is most likely a descendant of the Cenozoic sawshark, Pristiophorus lanceolatus from New Zealand and Australia. It is a poorly known family and only consists of six members: P. cirratus, P. delicatus, P. japinicus, P. nancyae, P. nudipinnis, and P. schroederi. Three specimens of Pristiophoridae schroederi were discovered; 38.3, 64.5, and 80.5 centimeters in length, were collected by an incidental product of exploratory fishing operations by the U.S. Bureau of Commercial Fisheries. One was discovered in the Santaren Channel and two from the Atlantic, just north of Little Bahama Bank. (Full article...)
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The bigeyed sixgill shark (Hexanchus nakamurai) is a cow shark of the familyHexanchidae. Its dorsal surface has a brownish-gray color, and is sharply separated from the light coloring of its ventral surface. The eyes are a fluorescent green while the shark is alive. The body of this shark is small, slim, and fusiform in shape. As the name suggests, this shark has six gill slits, unusual among most shark species. The head is narrow and somewhat flattened, and the mouth contains 5 rows of large, comb-shaped teeth. This shark's single dorsal fin is pushed back towards the caudal fin, and is behind the pelvic fins. The upper caudal fin is much longer than the lower, with a deep notch near the tip. All fins have thin white margins on the edge. In juveniles, the upper caudal fin has a black tip. (Full article...)
The night shark (Carcharhinus signatus) is a species of requiem shark, in the familyCarcharhinidae, found in the temperate and tropical waters of the Atlantic Ocean. An inhabitant of the outer continental shelf and upper continental slope, this shark most commonly occurs at depths of 50–600 m (160–1,970 ft) and conducts a diel vertical migration, spending the day in deeper water and moving into shallower waters at night. Off northeastern Brazil, large numbers congregate around seamounts of varying depths. A slender, streamlined species, the night shark typically reaches a length of 2 m (6.6 ft). It can be identified by its long, pointed snout and large, green eyes (when alive), and is dark grayish blue or brown above and white below.
Night sharks are quick, nocturnally active, schoolingpredators that feed mainly on small bony fishes and squid. Reproduction is viviparous as with the other members of its family; females mate during the summer and give birth to litters of usually 12–18 pups after a gestation period of a year. This deepwater species is not known to pose a danger to humans. It is caught incidentally by commercialtuna and swordfishlongline fisheries in the western Atlantic, and also by a targeted longline fishery operating off northeastern Brazil. The night shark is highly valued for its fins, and additionally as a source of meat, liver oil, and fishmeal. However, most sharks caught off northeastern Brazil have been found to contain unsafe concentrations of mercury.
Because of its low reproductive rate and historically documented declines in areas such as the Caribbean, the night shark has been assessed as vulnerable by the American Fisheries Society. A population assessment has indicated that this species is secure in the waters off the United States, but this may not be true elsewhere. (Full article...)
The Maguga Dam is a dam on the Komati River in Eswatini. It is 115 metres (377 ft) high and is located about 12 kilometres (7.5 mi) south of Piggs Peak. It was built as a joint project of the governments of South Africa and Eswatini. As of 2005, it was the largest public works project ever undertaken by Eswatini. The dam was completed in mid-2001. (Full article...)
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Ringedals Dam is a gravity dam by Ringedalsvatnet at Tyssedal in Oddamunicipality in the county of Hordaland, Norway. The dam was built in stages between 1909 and 1918 in connection with the hydroelectric power plant in Tyssedal and the factories in Odda. When the dam was completed in 1918 it was one of Europe’s largest gravity dams with a reservoir capacity of 222 million m3. The dam is built in Cyclopean concrete with 30% large-sized stones (plums) and dressed on both sides with approximately 20,000 m² of hand-cut granite stone, the largest of its kind in Norway. The dam is crowned by the date and initials of managing director Ragnvald Blakstad and topped with merlons in Neo-Romanesque style.
Ringedalsvatnet is today the reservoir of Oksla Hydroelectric Power Plant at Sørfjorden. The reservoir has a capacity of 426 million m³ and the power station is every year producing approximately 900 GWh. (Full article...)
Construction of the dam began in the Soviet era, in 1976, but was abandoned in 1993 after the collapse of the Soviet Union. Over three decades only preliminary construction has been carried out on the dam. Due to its controversial state, construction was suspended in August 2012 pending World Bank reports. The project was restarted by the Tajik government in 2016. The power plant's first unit was commissioned in November 2018 and second in September 2019, both on lower hydraulic head.
The Punchiná Dam is an embankment dam on the Guatapé River 17 kilometres (11 mi) east of San Carlos in Antioquia Department, Colombia. The dam creates Punchiná Reservoir which is part of the 1,240 megawatts (1,660,000 hp) San Carlos Hydroelectric Power Plant. The power plant was completed in two 620 megawatts (830,000 hp) stages, the first was completed in 1984 and the second in 1987. It is the largest power station in Colombia. (Full article...)
The Malpaso Dam, officially known as the Nezahualcóyotl Dam, is located in the Centro region of Chiapas, Mexico near the border with Tabasco and Veracruz. It was the first of several major dams built on the Grijalva River to generate hydroelectric energy and has the second largest reservoir in Mexico, after the Belisario Dominguez Dam. Construction of the dam occurred in the 1960s and flooded not only the riverbed but also hectares of rainforest and farmland, various towns and villages and archeological sites. These include the former town of Quechula, whose 16th century Dominican church will appear when water is at low levels, and the archeological site of San Isidro which contains one of only two known double Mesoamerican ball courts. Commissioning of the dam's 1,080 MW power station began in 1969 and ended in 1977. The reservoir and later construction of a federal highway has spurred ecotourism in the area. (Full article...)
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The Zimapán Dam, also known as Fernando Hiriart Balderrama Dam, is an arch dam on the Moctezuma River about 15 km (9 mi) southwest of Zimapán in Hidalgo state, Mexico. The primary purpose of the dam is hydroelectric power production and it services a 292 MW power station with water. (Full article...)
It uses water provided by five reservoirs high up in the Papenoo Valley, above the commune. Each reservoir is created on the Papenoo River or a tributary by an embankment dam. From highest in elevation to lowest; Vaitapaa Dam at , which lies at an elevation of 411 m (1,348 ft) above sea level, is 15 m (49 ft) tall. It withholds a reservoir of 8,000 m3 (6.5 acre⋅ft). Next, at an elevation of 400 m (1,300 ft), Tahinu Dam, at is 33 m (108 ft) high and withholds a larger reservoir of 1,500,000 m3 (1,200 acre⋅ft). It is the tallest dam in Tahiti. Moving down is Vainavenave Dam at which lies at 399 m (1,309 ft) above sea level, is 29 m (95 ft) tall, and withholds a reservoir of 150,000 m3 (120 acre⋅ft). Fourth down the valley is the Vaituoru Dam at an elevation of 200 m (660 ft) with a reservoir capacity of 100,000 m3 (81 acre⋅ft). It is located at . Finally is the Tevaiohiro Dam at 85 m (279 ft) above sea level with a reservoir volume of 150,000 m3 (120 acre⋅ft). It is located at .
Water from the reservoirs is sent to three separate power stations via 25.5 km (15.8 mi) of penstock. The power station highest in elevation, Papenoo 1 contains four 4 MW Pelton-turbine-generators and is located at . Next downstream is Papenoo 2 at which contains one 4 MW Pelton turbine-generators. Lastly, Papenoo 3 contains two 4 MW Pelton turbine-generators and is located at . (Full article...)
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The Alpe Gera Dam is a gravity dam on the Cormor River in a lateral valley of Valmalenco 17 km (11 mi) northeast of Sondrio in the Lombardy region of Italy. It is 174 m (571 ft) tall and supports a 35 MW hydroelectric power station.
The dam was constructed between 1958 and 1964 and is best known for the concrete placement techniques used during its construction. Instead of concrete being poured into conventional monoliths, it was poured in layers with a lean mix. Next, the concrete was settled with immersed vibrators and then contraction joints were cut into the layer. These methods were not only cost-saving but instrumental in the development of roller-compacted concrete in dam construction. (Full article...)
The dam would be 103 metres (338 ft) high and flood approximately 97 square kilometres (24,000 acres) of the Zambezi valley. The estimated cost of the project is US$4.2 billion. Once the dam is completed, it is expected that most of the generated power will be sold to South Africa, because of the lack of transmission infrastructure in Mozambique.
The proposed dam is highly controversial because it would force the relocation of 1,400 families, and affect the livelihoods of a further 200,000 people downriver. Because the dam would be operated on a peaking basis, large daily fluctuations in river flow would ruin existing irrigation systems and affect aquaculture in the river's extensive delta. The United Nations has described this project as the "least environmentally acceptable major dam project in Africa."
In 2015, the Mozambique government announced it would start construction of the dam. The construction was contracted to Camargo Corrêa of Brazil, INSITEC of Mozambique, and Electricidade de Moçambique. In 2020, Mozambique President Filipe Nyusi wished construction of the dam started before 2024.
The Kyzyl-Agash Dam failure (Kazakh: Qyzylaǵash oqıǵasy), occurred in a dam located outside the village of Kyzyl-Agash, Jetisu Region, Kazakhstan. On 11 March 2010, the dam burst, flooding the village. At least 43 people were killed, 211 people were injured, and over 1000 evacuated from the village.
Opposition sources report a much higher figure for the death toll. An opposition newspaper Svoboda Slova reports that at least 200 have died, mostly children and old people, but an exact, official count is prohibited by the administration. (Full article...)
The Adolfo Ruiz Cortines Dam, built in 1955 is a medium-sized reservoir, located in the Mexican state of Sonora; it provides water for the Río Mayo Irrigation district. At 1,100 million m3 it ranks the 25th largest reservoir in Mexico. In 1985 the dam overflowed reservoir forcing the evacuation of 20,000 people. (Full article...)
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Kaptai Dam (Bengali: কাপ্তাই বাঁধ) is on the Karnaphuli River at Kaptai, 65 km (40 mi) upstream from Chittagong in Rangamati District, Bangladesh. It is an earth-fill embankment dam with a reservoir (known as Kaptai Lake) with water storage capacity of 6,477 million cubic metres (5,251,000 acre⋅ft). The primary purpose of the dam and reservoir was to generate hydroelectric power. Construction was completed in 1962, in then-East Pakistan. The generators in the 230 MW (310,000 hp) Karnafuli Hydroelectric Power Station were commissioned between 1962 and 1988. It is the only hydroelectric power station in Bangladesh. (Full article...)
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The Keddara Dam, or Barrage Keddara, is an embankment dam 6 km (4 mi) northwest of Keddara on the Boudouaou River in Boumerdès Province, Algeria. Constructed between 1982 and 1987 by Yugoslav company Hidrotehnika, the primary purpose of the dam is water supply for irrigation and municipal use in Algiers which is located 35 km (22 mi) to the west. The dam's reservoir has a capacity of 146,500,000 m3 (118,769 acre⋅ft) which is collected from drainage and the Hamiz Dam 7.6 km (5 mi) to the west and the Beni Amrane Dam 17 km (11 mi) to the east. (Full article...)
The Emilio López Zamora dam, also known as the Ensenada dam, is a dam with a water treatment plant in Ensenada, Baja California, Mexico, on the basin of the Ensenada stream. Its main use is the containment of flash floods, and as a water supply for the city. It was built in 1976 and is administered by Mexico's National Water Commission [es] (CONAGUA). (Full article...)
The primary purpose of the dam is flood control; it provides flood protection for 40,000 people and over 13,000 residential structures. The dam is the final component of the Portugués and Bucana Flood Protection Project and the first dam of its type constructed by the U.S. Army Corps of Engineers in the United States or Caribbean. The final cost of the dam was estimated at $375 million; 75% is funded by the U.S. Government and 25% by the Government of Puerto Rico. It is the first dam ever built in the United States that uses the single-centered roller-compacted concrete thick arch technique.
An estimated inauguration date of October 2013 was announced in 2011 but was not met. Subsequently, an inauguration date of 28 January 2014 was also announced. The dam was structurally completed in December 2013 and inaugurated on 5 February 2014. The dam is operated by the Puerto Rico Department of Natural and Environmental Resources. (Full article...)
The Casecnan Irrigation and Power Generation Project is also located in Rizal, Nueva Ecija. The P6.75-B Project provides irrigation to 26,920 hectares of new farms in the Science City of Munoz, Talugtog, Guimba, Cuyapo, and Nampicuan, all of Nueva Ecija. It generates 150 megawatts of power for the Luzon grid that will supply cheap electricity to millions of people in Luzon including Metro Manila.[1][2] (Full article...)
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The Usoi Dam is a natural landslide dam along the Murghab River in Tajikistan. At 567 metres (1,860 ft) high, it is the tallest dam in the world, either natural or man-made. The dam was created on February 18, 1911, when the 7.4-MsSarez earthquake caused a massive landslide that blocked the flow of the river.
The dam is formed of approximately 2 cubic kilometres (0.48 cu mi) of rock dislodged from the steeply sloped river valley of the Murghab, which cuts from east to west through the high and rough Pamir Mountains. It is named after the village of Usoi, which was completely buried by the 1911 landslide. The dam rises to a height of 500 to 700 metres (1,600 to 2,300 ft) from the original valley floor.
The basin formed by Usoi Dam now holds Sarez Lake, a 55.8-kilometre (34.7 mi)-long lake holding 16.074 cubic kilometres (13,031,000 acre⋅ft) of water. Water does not flow over the top of the dam, which would quickly cause it to erode away; instead, water seeps out of the base of the dam at a rate which approximately matches the rate of inflow, maintaining the lake at a relatively constant level. The level thus only rises an average of 20 cm per year. The flow averages about 45 cubic meters per second, with an annual variation of 35-80 cubic meters per second and dissipates about 250 megawatts.
Geologists are concerned that the Usoi Dam may become unstable during future large-magnitude earthquakes, which are relatively common in the seismically active Pamirs, and might collapse due to liquefaction or subsequent landslides during such an event. Collapse of the dam would unleash a locally catastrophic flood. The Murghab's river valley tends to be relatively narrow and steep. This would focus and maintain any flood's destructive power as it swept through the valley of the Murghob District.
The dam wall survived a localised 7.2 magnitude earthquake, the 2015 Tajikistan earthquake, on the 7th December 2015 with no visible signs of deterioration. (Full article...)
The proposed dam became the rallying point for protest in 1986–87 by hundreds of thousands of Latvians resulting with the cancellation of the project, in spite of the vast expenditures already poured into the project. The protest was a precursor of the Latvian Third Awakening. (Full article...)
The Rio Cobre Dam is a diversion dam on the Rio Cobre near Spanish Town in Saint Catherine Parish, Jamaica. It is owned by the National Irrigation Commission. The primary purpose of the dam is to divert water into a canal on its right bank for the irrigation of up to 12,000 ha (30,000 acres) to the south. It also provides municipal water to Spanish Town. The scheme contains more than 48 km (30 mi) of canals and waters sugar cane, bananas and cattle.
Plans for the scheme began with then Governor of JamaicaJohn Peter Grant in 1870. Construction began at the end of 1872 and by June 1876 the dam and canals were complete.
In the late 1800s the West India Electric Company constructed a 900 kW hydroelectric power station upstream at Bog Walk to power a tram system in Kingston. On 24 June 1904, while workers were cleaning the station's penstock, water was accidentally released down it killing 33 of them. The power station was closed in 1966, 62 years after the accident but, the dam, the ruins of the turbine house and some of the concrete supports of the penstock still exist today. (Full article...)
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Hojum Power Station (alt. Håjum Power Station) is the second hydroelectric power station in Trollhättan, the first one being the older Olidan Power Station. While the first two turbines were taken into service in 1938, a third one was built and started in 1992. The first two are rated at 50 MW, while the third is rated at 70 MW.
The station is mainly located underground in a large mountain hall. This design was chosen because of the political instability in Europe at the time, which later led to the second world war. The relatively small building above ground was drawn by the Swedisharchitect Erik Hahr. (Full article...)
The power plant collects water resources from six bodies of water in Tjodanvassdraget, the mountain plateau north of Lysefjorden. The fall height is 892 metres and the installed output is 110 MW (Full article...)
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The Achelous (Greek: Αχελώος, Ancient Greek: ἈχελῷοςAkhelôios), also Acheloos, is a river in Epirus, western Greece. It is 220 km (137 mi) long. It formed the boundary between Acarnania and Aetolia of antiquity. It empties into the Ionian Sea. In ancient times its spirit was venerated as the river god Achelous.
Herodotus, taking notice of the shoreline-transforming power of the Acheloos River, even compared it to the Nile in this respect: :'There are other rivers as well which, though not as large as the Nile, have had substantial results. In particular (although I could name others), there is the Achelous, which flows through Acarnania into the sea and has already turned half the Echinades islands into mainland.' (2.10, trans. Waterfield)
It is said to have been called more anciently Thoas, Axenus and Thestius. (Full article...)
{{ Transclude list item excerpts as random slideshow | List of mountain ranges | section=Mountain ranges on Earth }} Select from Earth section, avoiding Moon
This mountainous area was named after Danish politician Thorvald Stauning (1873–1942) who had helped to finance expeditions to east Greenland planned and carried out by Danish explorers. (Full article...)
The range comprises two major groups of peaks. The southern section rises from a point near Burnt Peak in Lincoln County, reaching the summit of Mt. Grafton, 10,990 feet (3,350 m), just north of the border with White Pine County. To the west are remote Cave Valley and the Egan Range, while to the east are U.S. Route 93 and the Fairview Range (Lincoln County). North of Mt. Grafton, the range drops quickly to a line of lower summits, eventually reaching 7,723-foot (2,354 m) Connors Pass. That is where U.S. Route 50, the "Loneliest Highway in America", crosses the range, connecting the nearby community of Ely with the Great Basin National Park and west-central Utah. North of Connors Pass the range continues into its higher northern section. To the west is Ely, Nevada, while to the east are Spring Valley and the high Snake Range, (including Great Basin National Park, Wheeler Peak, and Mt. Moriah). Within this section of the Schell Creek Range are Cave Lake State Park and the scenic road over Success Summit into Duck Creek Basin. The crest continues to rise, reaching South Schell Peak at 11,785 feet (3,592 m), Taft Peak at 11,734 feet (3,577 m), and North Schell Peak which, at 11,883 feet (3,622 m), is the high point of the range. Nearby are the Timber Creek and Berry Creek campgrounds (and trailheads).
The range then makes a slow descent to lower elevations, dropping to Schellbourne Pass at 7,984 ft (2,434 m), where the Overland Stage Line, the Pony Express, and the Transcontinental Telegraph made their way through the Great Basin. Just west of the range was the Egan Canyon Pony Express Station. From there, the range ascends to Becky Peak at 10,008 feet (3,050 m) before quickly descending to the floor of Steptoe Valley near Lages Station. (Full article...)
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Stogovo (Macedonian: Стогово; Albanian: Stogovë) is a mountain in the western part of North Macedonia. It has impressive peaks: Golem Rid (2278 m), Babin Srt (2242 m), Kanesh and many more higher than 2000 meters above the sea level. Mountain Stogovo can be easily reached by bus that goes from the capital of North Macedonia – Skopje to the town of Debar, at the place called "Boshkov most" (bridge). The nature is almost totally preserved on the range, because this mountain is far away from the large populated areas in the country and it is not frequently visited by mountain climbers. (Full article...)
The Arbuckles contain the most diverse suite of mineral resources in Oklahoma: limestone, dolomite, glass sand, granite, sand and gravel, shale, cement, iron ore, lead, zinc, tar sands, and oil and gas; all these minerals are, or have been, produced commercially.
The Appalachians are also subdivided by a number of large plateaus and additional subplateus. These are commonly not considered subranges although they do contain some features referred to as mountains which are assigned to both their geographic "range" and the more general Appalachian Mountains. These plateaus, such as the Allegheny Plateau, are considered provinces of the Appalachian Highlands and the mountains assigned to them are instead considered pieces of dissected plateaus.
Additionally, subranges and ridges of subranges (Such as the Yew Mountains) are inconsistently related to the Appalachian Mountain Range. No clear distinction exists as to what units qualify as directly related subranges of the Appalachians until the level of mountain. As such, the distinction is often arbitrary and based on person preference by the geographer or geologist publishing material. This has led to the distinction being largely unrelated to area, geological features, or topography. This list is more comprehensive to account for that variation and includes the parent range of each subrange noted. This list includes physiographic regions, for information of the physiographic regions, provinces, and sections: refer to the Appalachian Highlands page for American sections and the Appalachian Uplands page for Canadian sections.
Due to the lack of solid distinctions in the requirements of an area to be a range, this list includes most physiographic divisions, many larger ridges, plateaus, mountain complexes, most stratigraphic ridges, certain lowlands and uplands, local highlands, and certain other types of geographic and geological features. This list is not a comprehensive list of every peak and summit of the Appalachians, individual mountains, when included, are generally individual politically but not geographically, and each inclusion must meet the set of criteria used to define a subrange. (Full article...)
The Front Range runs north-south between Casper, Wyoming, and Pueblo, Colorado, and rises nearly 10,000 feet above the Great Plains. Longs Peak, Mount Blue Sky, and Pikes Peak are its most prominent peaks, visible from the Interstate 25 corridor. The area is a popular destination for mountain biking, hiking, climbing, and camping during the warmer months and for skiing and snowboarding during winter. Millions of years ago, the present-day Front Range was home to ancient mountain ranges, deserts, beaches, and even oceans.
The name "Front Range" is also applied to the Front Range Urban Corridor, the populated region of Colorado and Wyoming just east of the mountain range and extending from Cheyenne, Wyoming south to Pueblo, Colorado. This urban corridor benefits from the weather-moderating effect of the Front Range mountains, which help block prevailing storms. (Full article...)
The Whitefish Range, however, is not particularly high. The highest peaks in the U.S. are Nasukoin Mountain, 8,086 feet (2,465 m), and Lake Mountain, 7,814 feet (2,382 m). In Canada, the highest peak is Mount Doupe, 8,740 feet (2,660 m).
In the U.S., a large portion of the range has been removed from multiple use designation, including the 34,000-acre Ten Lakes Wilderness Study Area on the Kootenai National Forest. Ten Lakes WSA contains more than 89 miles of trails, many mountain lakes, alpine peaks, and views into Canada and Glacier National Park. (Full article...)
Haystack Mountain, which reaches 8,819 feet (2,688 m), is the tallest peak in the range. The three other highest peaks are Jack Mountain at 8,752 feet (2,668 m), Bull Mountain at 8,609 feet (2,624 m), and Thunderbolt Mountain at 8,597 feet (2,620 m). All four peaks are in Jefferson County. (Full article...)
The Dinaric Alps extend for approximately 645 kilometres (401 mi) along the western Balkan Peninsula from the Julian Alps of the northeast Italy, downwards to the Šar and Korabmassif, where their direction changes. The Accursed Mountains are the highest section of the entire Dinaric Alps; this section stretches from Albania to Kosovo and eastern Montenegro. Maja Jezercë, standing at 2,694 metres (8,839 ft) above the Adriatic, is the highest peak and is located in Albania.
The Dinaric Alps are one of the most rugged and extensive mountainous areas of Europe, alongside the Caucasus Mountains, Alps, Pyrenees, Carpathian Mountains and Scandinavian Mountains. They are formed largely of Mesozoic and Cenozoicsedimentary rocks of dolomite, limestone, sandstone and conglomerates formed by seas and lakes that once covered the area. During the Alpine earth movements that occurred 50 to 100 million years ago, immense lateral pressures folded and overthrust the rocks in a great arc around the old rigid block of the northeast. The main tectonic phase of the orogenesis in the area of the Dinaric Karst took place in Cenozoic Era (Paleogene) as a result of the Adriatic Microplate (Adria) collision with Europe, and the process is still active. The Dinaric Alps were thrown up in more or less parallel ranges, stretching like necklaces from the Julian Alps as far as northern Albania and Kosovo, where the mountainous terrain subsides to make way for the waters of the Drin River and the plains of Kosovo. (Full article...)
The Ozarks, also known as the Ozark Mountains, Ozark Highlands or Ozark Plateau, is a physiographic region in the U.S. states of Missouri, Arkansas, Oklahoma and the extreme southeastern corner of Kansas. The Ozarks cover a significant portion of northern Arkansas and most of the southern half of Missouri, extending from Interstate 40 in central Arkansas to Interstate 70 in central Missouri.
There are two mountain ranges in the Ozarks: the Boston Mountains of Arkansas and Oklahoma, as well as the St. Francois Mountains of Missouri. Wahzhazhe Summit (formerly known as Buffalo Lookout), is the highest point in the Ozarks at 2,561 feet (781 m), and is located in the Boston Mountains, 3.4 miles (5.5 km) east of Pettigrew, Newton County, Arkansas. Geologically, the area is a broad dome with the exposed core in the ancient St. Francois Mountains. The Ozarks cover nearly 47,000 square miles (120,000 km2), making it the most extensive highland region between the Appalachians and Rockies. Together with the Ouachita Mountains, the area is known as the U.S. Interior Highlands.
The Borborema Plateau (PortuguesePlanalto da Borborema, also known as the Serra da Borborema) is a plateau in northeastern Brazil which extends across the states of Pernambuco, Paraíba, and Rio Grande do Norte. The plateau is the northeasternmost portion of the Brazilian Highlands and is the most relevant watershed of its region. It ranges approximately 400 kilometres (250 mi) from north to south and 200 kilometres (120 mi) from east to west. More than 100 rivers originate from the plateau, including the Moxotó, Mundaú, Pajeú, Paraíba do Norte, Seridó, and Una.
The Borborema Plateau serves as an orographic barrier, despite its relatively low elevation, against the moist easterly winds of the Atlantic Ocean. Areas west of the plateau, which make up part of the sertão, are arid and prone to drought. The Pajeú River, the largest tributary of the São Francisco River, originates from the Borborema. (Full article...)
The Kaweka Range (also known as the Kaweka Ranges) of mountains is located in inland Hawke's Bay in the eastern North Island (Te Ika-a-Māui) of New Zealand. It forms part of the mountainous spine of the North Island which extends from Wellington to East Cape, including the Tararua and Ruahine ranges.
The range lies between the city of Napier, 55 kilometres (34 mi) to the southeast, and Lake Taupō, 50 kilometres (31 mi) to the northwest. It is the source of many rivers which flow into Hawke Bay, including among them the Tutaekuri, Mohaka, and Ngaruroro Rivers.
The highest point in the range is Kaweka J (1,724 metres (5,656 ft)). The bush line varies from 1000 m to 1300 m.
A tramping track follows the ridge line of the entire range. The Kaweka challenge is a running race held annually in the range since 1990. (Full article...)
The Lower Himalayan Range (Nepali: पर्वत शृङ्खला parbat shrinkhalā) – also called the Middle Himalayas or Lesser Himalayas or Himachal – is a major east–west mountain range with elevations 3,700 to 4,500 m (12,000 to 14,500 feet) in the northernmost regions of the Indian subcontinent along the crest, paralleling the much higher High Himalayas range from the Indus River in Pakistan across northern India, Nepal and Bhutan but then the two ranges become increasingly difficult to differentiate east of Bhutan as the ranges approach the Brahmaputra River. The Himachal range also parallels the lower Shiwalik or Churia Range (Outer Himalaya) to the south. The Pir Panjal is the largest range of the Lesser Himalayas. (Full article...)
The divergence rate between the two plates along the ridge is believed to vary from about 5.4 centimetres per year (2.1 in/year) near 65°S to 7.4 centimetres per year (2.9 in/year) near the Udintsev Fracture Zone at 55°S.
The ridge is related to the Late Cretaceous breakup of Gondwana. To the southeast the historic Bellingshausen Plate separated the Pacific and Antarctic plates between about 84 to 61 million years ago. Until about 33 million years ago, the Proto-Antipodes Fracture Zone well to the south separated two independent spreading centers, now merged, being the Antarctic–Pacific Ridge and that of the Antarctic–Campbell Plateau. (Full article...)
The terms for 'mountain' are Adrar and adras in some Berber languages, and these terms are believed to be cognates of the toponymAtlas. The mountains are home to a number of animals and plants which are mostly found within Africa but some of which can be found in Europe. Many of these species are endangered and a few are already extinct. The weather is generally cool but summers are sunny, and the average temperature there is 25 °C. (Full article...)
The highest peak is Ogreyak (also known as Kadiytsa) at 1,924 m. Nearby towns include Simitli to the northeast in Bulgaria and Pehčevo to the southwest in North Macedonia. (Full article...)
The Conger Range, also called the Conger Mountains, is a mountain range in Quttinirpaaq National Park on Ellesmere Island, Nunavut, Canada, beginning about 16 km (10 mi) west of Mount Osborne. It is part of the Arctic Cordillera which is a vast dissected mountain system extending from Ellesmere Island to the northernmost tip of Labrador and northeastern Quebec. The Conger Range is a structural extension of the Garfield Range and continues into the highlands north of the head of Hare Fiord. The overall extent of the range is about 180 km (112 mi). Most of its peaks are ice-covered, although nearly all of the southern slopes are ice-free. Many of the valleys between the peaks are filled with glacial tongues spilling out to the south from the Grand Land Ice Cap. Its highest point is Mount Biederbick at 1,542 m (5,059 ft).
The Conger Range was named by AmericanPolar explorer Adolphus Greely, who sighted them during a dog sledding exploration to the interior of northern Ellesmere Island in 1882. (Full article...)
The mountain borders Emmaus just south of Allentown and comprises a ridge of low mountains passing east of Reading, and then extends due west. South Mountain is a continuation of the New England Province and is the southern end of the Hudson Highlands. The mountain is a core geographic feature throughout much of the Pennsylvania side of the Lehigh Valley. The mountain is called the Reading Prong by geologists.
Unlike Blue Mountain to its north, South Mountain does not follow a straight geographic line. The mountain ranges in elevation between 500 and 1,300 feet (150 and 400 m) above sea level. The ridge is made of metamorphic rocks and gneiss, which date to the Precambrian era and range from about 570 million to 1,600 million years old.
South Mountain is largely undeveloped in its northern extension due to conservation efforts and the mountain's steep slope. This makes it a beautiful backdrop to the viewpoints of the Lehigh Valley, including, at night, the city lights of Allentown. The southern end of the mountain extends west along U.S. Route 422 and the southeastern border of Berks County, providing views of Blue Mountain to the north, and Mount Penn, which comprises part of the prong and the city of Reading to the east.
The southernmost peaks were at one time home to many exclusive sanitariums and resorts, now all defunct except for the Caron Foundation. South Mountain serves as the transmitter site for several local radio and television stations, including the independent television stationWFMZ-TV, which maintains both its transmitter and studio facilities on the mountain, south of Allentown. (Full article...)
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The Magaliesberg (historically also known as Macalisberg or Cashan Mountains) of northern South Africa, is a modest but well-defined mountain range composed mainly of quartzites. It rises at a point south of the Pilanesberg (and the Pilanesberg National Park) to form a curved prominence that intersects suburban Pretoria before it peters out some 50 km (31 mi) to the east, just south of Bronkhorstspruit. The highest point of the Magaliesberg is reached at Nooitgedacht, about 1,852 metres (6,076 ft) above sea level. A cableway reaching to the top of the mountain range is located at Hartbeespoort Dam, providing sweeping views of the Magaliesberg and surrounding area. (Full article...)
The Kurze Mountains were discovered and plotted from aerial photographs taken by the Third German Antarctic Expedition under Alfred Ritscher, 1938–39, who named them for the director of the Naval Division of the former Marineleitung (German Admiralty). They were remapped by the Norsk Polarinstitutt from surveys and aerial photos taken by the Sixth Norwegian Antarctic Expedition, 1956–60, and given the name "Holtedahlfjella." The correlation of the prior name (Kurze) with this feature is quite definite and is recommended for the sake of international uniformity and historical continuity. (Full article...)
The Sierra Cayey (Spanish: Sierra de Cayey) is a mountain range in the main island of Puerto Rico. It is located in the southeast section of the island. Its elevations do not exceed 1000 m (3,280 ft.).
The Grande de Loíza, which is one of the most important rivers in Puerto Rico, has its sources in this range within the municipality of San Lorenzo. The La Plata River flows through the Cayey Valley where the town of Cayey is located on the northern slope of the range. There are tobacco and coffee crops in the area. (Full article...)
Geologic evidence indicates that the mountains were formed during the break-up of the supercontinent of Gondwana. The mountains came along the west coast of India somewhere in the late Jurassic and early Cretaceous period when India separated from the African continent. The mountains can be roughly divided into three parts, northern section with elevation ranging from 900–1,500 m (3,000–4,900 ft), middle section starting from south of Goa with a lower elevation of less than 900 m (3,000 ft) and the southern section where the altitude rises again. The Western Ghats have several peaks that rise above 2,000 m (6,600 ft), with Anamudi (2,695 m (8,842 ft)) being the highest peak. The average elevation is around 1,200 m (3,900 ft).
The Western Ghats form one of the major watersheds of India, feeding many perennial river systems that drain almost 40% of the land area of the country. Because of the higher elevation of the Deccan plateau on the west, most rivers flow from eastwards towards the Bay of Bengal, resulting in chiselled eastern slopes and steeper western slopes, facing the Arabian Sea. The Western Ghats plays an important role in determining the climate and seasons in India. It blocks the rain bearing monsoon winds flowing eastward from the Arabian Sea, resulting in rainfall along the western coast. By the time the air rises above the mountains, it becomes dry, forming a rain shadow region with very less rainfall on the leeward side towards the interior of the Deccan plateau.
The Western Ghats region is a biodiversity hotspot. It contains of a large number of different species of flora and fauna, significant of which are endemic to this region. At least 325 globally threatened species occur in the Western Ghats. The region was declared as a UNESCOWorld Heritage Site in 2012. (Full article...)
{{ Transclude list item excerpts as random slideshow | List of dams and reservoirs | section=Africa | sectiononly=yes }} Should pick only the international dams
The Kariba Dam is a double curvature concrete arch dam in the Kariba Gorge of the Zambezi river basin between Zambia and Zimbabwe. The dam stands 128 metres (420 ft) tall and 579 metres (1,900 ft) long. The dam forms Lake Kariba, which extends for 280 kilometres (170 mi) and holds 185 cubic kilometres (150,000,000 acre⋅ft) of water. (Full article...)
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The Gilgel Gibe III Dam is a 250m high roller-compacted concrete dam with an associated hydroelectric power plant on the Omo River in Ethiopia. It is located about 62 km (39 mi) west of Sodo in the Southern Nations, Nationalities, and Peoples' Region. Once fully commissioned, it will be the third largest hydroelectric plant in Africa with a power output of about 1,870 Megawatt (MW), thus more than doubling total installed capacity in Ethiopia from its 2007 level of 814 MW. The Gibe III dam is part of the Gibe cascade, a series of dams including the existing Gibe I dam (184 MW) and Gibe II power station (420 MW) as well as the planned Gibe IV (1,472 MW) and Gibe V (560 MW) dams. The existing dams are owned and operated by the state-owned Ethiopian Electric Power, which is also the client for the Gibe III Dam.
The US$1.8 billion project began in 2006 and electricity generation started in October 2015. The remaining generators were operational by 2016. The project has experienced serious delays; in May 2012, full commissioning had been scheduled for June 2013. The dam was inaugurated by Prime Minister Hailemariam Desalegn on 17 December 2016.
Local and international environmental groups forecast major negative environmental and social impacts of the dam and criticized the project's environmental and social impact assessment as insufficient. Because of this and accusations that the entire approval process for the project was suspect, funding for the full construction cost was not secured, as the African Development Bank delayed a decision about a loan pending a review of the dam's environmental impact by its compliance review and mediation unit. This dates back to August 2009 when they accepted a call from NGOs for such a review. In August 2010 Ethiopian Prime Minister Meles Zenawi vowed to complete the dam "at any cost", saying the dam's critics "don’t want to see developed Africa; they want us to remain undeveloped and backward to serve their tourists as a museum." (Full article...)
The plant was inaugurated by the Malian Prime Minister Abdoulaye Maïga in December 2022. It cost US$329 million and the 280 km (170 mi) of transmission lines cost US$65 million. The project received 85 percent of its funding from the Exim Bank of China along with US$1 million from the EU-Africa Infrastructure Trust Fund and US$1.4 million from the International Development Association and European Investment Bank.
It has an installed capacity of 140 megawatts (190,000 hp) and will use the outflows of the Manantali Dam upstream to regulation water flow into the plant. A 1,230 m (4,040 ft) long weir just above the water fall directs water into a channel which will feed the power house just downstream of the falls. The power house contains three 46.6 MW Kaplan turbine-generators. The difference in elevation the water fall and weir provides a hydraulic head (water drop) of 22.5 m (74 ft). (Full article...)
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The Tsiazompaniry Dam is a buttress dam on the Varahina-South River, a tributary of the Ikopa River, near Tsiazompaniry in the Analamanga Region of Madagascar. The dam was constructed by a French firm in 1956. It creates Lake Tsiazompaniry, the largest reservoir in the country, which has a surface area of 31 km2 (12 sq mi) and a storage volume of 260,000,000 m3 (210,000 acre⋅ft). A second buttress dam, 1 km (0.62 mi) northwest of the main dam helps withhold the reservoir. Water released from the dam supplies a regulated flow to hydroelectric power station at the Antelomita Dam downstream. Efforts to install a 5.25 MW power station at the base of the dam began in 2011. (Full article...)
The Akosombo Dam, also known as the Volta Dam, is a hydroelectric dam on the Volta River in southeastern Ghana in the Akosombo gorge and part of the Volta River Authority. The construction of the dam flooded part of the Volta River Basin and led to the subsequent creation of Lake Volta. Lake Volta is the largest man-made lake in the world by surface area. It covers 8,502 square kilometres (3,283 sq mi), which is 3.6% of Ghana's land area. With a volume of 148 cubic kilometers, Lake Volta is the world's third largest man-made lake by volume; the largest being Lake Kariba which contains 185 cubic kilometers of water.
The primary purpose of the Akosombo Dam was to provide electricity for the aluminium industry. The Akosombo Dam was called "the largest single investment in the economic development plans of Ghana." The dam is significant for providing the majority of both Togo and Benin's electricity, although the construction of the Adjarala Dam (on Togo's Mono River) hopes to reduce these countries' reliance on imported electricity. The dam's original electrical output was 912 megawatts (1,223,000 hp), which was upgraded to 1,020 megawatts (1,370,000 hp) in a retrofit project that was completed in 2006.
The flooding that created the Lake Volta reservoir displaced many people and had a significant impact on the local environment, including seismic activity that led to coastal erosion; a changed hydrology caused microclimatic changes with less rain and higher temperatures. The soil surrounding the lake is less fertile than the soil under it, and heavy agricultural use has required the use of fertilizers, which in turn has led to eutrophication, which caused, among others, the explosive growth of an invasive weed that renders water navigation and transportation difficult, and form a habitat for the vectors of water-borne illnesses such as bilharzia, river blindness and malaria. Resettlement of the displaced inhabitants proved complex and in some cases unsuccessful; traditional farming practices disappeared and poverty increased. (Full article...)
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The Kariba Dam is a double curvature concrete arch dam in the Kariba Gorge of the Zambezi river basin between Zambia and Zimbabwe. The dam stands 128 metres (420 ft) tall and 579 metres (1,900 ft) long. The dam forms Lake Kariba, which extends for 280 kilometres (170 mi) and holds 185 cubic kilometres (150,000,000 acre⋅ft) of water. (Full article...)
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The Kpong Dam, also known as the Akuse Dam, is a hydroelectric power generating dam on the lower Volta River near Akuse in Ghana. It is owned and operated by Volta River Authority. It was constructed between 1977 and 1982. Its power station has a capacity of 148 megawatts (198,000 hp) with all four units running, though the total nameplate capacity is 160 megawatts (210,000 hp).
The project supplements power production from Akosombo Dam, for the smelting of aluminium at VALCO in Tema. The project is located about 24 kilometres (15 mi) downstream of Akosombo Dam, and is about 80 kilometres (50 mi) from the city of Accra.
Because the reservoir upstream of the dam is relatively small, the plant operates as a "run-of-the-river" project, with river flow controlled at Akosombo. The design head of water at the plant is 11.75 metres (38.5 ft); the low head required the use of unusually large turbines for their power rating, with a Francis runner diameter of 8.2 metres (27 ft). The powerhouse is 148 metres (486 ft) long, 40 metres (130 ft) wide and 64 metres (210 ft). The main dam is made of earth with rockfill facing and is 18 metres (59 ft) high and 240 metres (790 ft) long. Dikes on the banks are 2,100 and 3,500 metres (6,900 and 11,500 ft) long. The spillway has a design capacity of 20,000 cubic metres per second (710,000 cu ft/s) and has 15 radial gates, each 11 metres (36 ft) wide by 13.5 metres (44 ft) high, with a total length of 280 metres (920 ft). The civil contractor for the project was Impregilo of Italy. Other components of the project include a 161 kV switchyard and transmission lines, four villages constructed to house people displaced by the project, and road construction.
In addition to power generation, the project provides irrigation water for agriculture, and municipal water supply. Bilharzia is a health hazard in the region which has increased since the construction of the dam. (Full article...)
The Gwenoro Dam is located inside Gwenoro Farm, an estate formerly owned by Ian Douglas Smith (1919-2007), a former Prime Minister of Rhodesia. The farm was seized in stages by the Government of Zimbabwe from Ian Smith and his family between 2002 and December 2012. The Gwenoro Dam supplies water to nearby Gweru and Shurugwi in Zimbabwe. The dam is constructed on the Runde River (formerly Lundi River; a medium density suburb in Gweru is named after the river (Lundi Park)). The name Gwenoro is derived from a wild animal found in the area known in the local language of Shona as Nhoro (gweNORO), which means a 'place inhabited by Nhoro'. The area is very beautiful and picturesque. The dam is full from January to June. Fish co-operatives are sprouting around the banks of this river. ZIMASCO used to run a mine club but has since stopped. What remains are only buildings. (Full article...)
The Wadi Qattara Dam, also referred to as Gattara or Al-Qattarah, is a clay-fill embankment dam located on Wadi Al-Qattara, 33 km (21 mi) east of Benghazi in Libya. Together with a secondary dam located 10 km (6 mi) downstream at and seven drop structures, the scheme was constructed after floods damaged the Benghazi area in 1938 and 1954. They were also constructed for irrigation water supply. Construction of the dams began in 1968 and was completed in 1971. However, a flood in 1979 severely damaged the main dam and destroyed the secondary dam downstream. The main dam was rehabilitated and the secondary dam was replaced with a rock-fill dam between 2000 and 2004 at a cost of US$30 million. The main dam was heightened 7 m (23 ft) and its total discharge capacity was increased to 240 m3/s (8,476 cu ft/s). Both dams were designed by Coyne et Bellier. (Full article...)
The Cahora Bassa Dam is located in Mozambique. It is one of two major dams on the Zambezi river, the other being the Kariba. The project began to come online in 1979 after much political debate. This dam uses the Zambezi River water to generate electricity by turning turbines. That energy is then sent to South Africa. The Cahora Bassa Dam forms Cahora Bassa Lake. The dam is jointly owned by Mozambique and Portugal. From independence until 2007, eighteen percent share of the dam and lake was owned by Mozambique and eighty-two percent by Portugal. Portugal sold down its share to 15 percent in 2007. The Cahora Bassa Dam is the largest hydroelectric power plant in southern Africa and the most efficient power generating station in Mozambique. (Full article...)
Completed in 1981, it was originally envisaged to become part of the Eastern National Water Carrier, a scheme to supply water to Namibia's capital Windhoek from the Okavango River, 1,000 kilometres (620 mi) to the north on the Angolan border. The scheme was never completed. Omatako Dam today only contains floods and supplies water to the Von Bach Dam. As such, it is one of three dams supplying the capital Windhoek with water. (Full article...)
The Aswan Dam, or more specifically since the 1980s, the Aswan High Dam, is one of the world's largest embankment dams, which was built across the Nile in Aswan, Egypt, between 1960 and 1970. When it was completed, it was the tallest earthen dam in the world, eclipsing the United States' Chatuge Dam. Its significance largely upstaged the previous Aswan Low Dam initially completed in 1902 downstream. Based on the success of the Low Dam, then at its maximum utilization, construction of the High Dam became a key objective of the new regime the Free Officers movement of 1952; with its ability to better control flooding, provide increased water storage for irrigation and generate hydroelectricity, the dam was seen as pivotal to Egypt's planned industrialization. Like the earlier implementation, the High Dam has had a significant effect on the economy and culture of Egypt.
Before the High Dam was built, even with the old dam in place, the annual flooding of the Nile during late summer had continued to pass largely unimpeded down the valley from its East Africandrainage basin. These floods brought high water with natural nutrients and minerals that annually enriched the fertile soil along its floodplain and delta; this predictability had made the Nile valley ideal for farming since ancient times. However, this natural flooding varied, since high-water years could destroy the whole crop, while low-water years could create widespread drought and consequently famine. Both these events had continued to occur periodically. As Egypt's population grew and technology increased, both a desire and the ability developed to completely control the flooding, and thus both protect and support farmland and its economically important cotton crop. With the greatly increased reservoir storage provided by the High Aswan Dam, the floods could be controlled and the water could be stored for later release over multiple years.
The Aswan Dam was designed by Nikolai Aleksandrovich Malyshev of the Moscow-based Hydroproject Institute. Designed for both irrigation and power generation, the dam incorporates a number of relatively new features, including a very deep grout curtain below its base. Although the reservoir will eventually silt in, even the most conservative estimates indicate the dam will give at least 200 years of service. (Full article...)
The Tsiazompaniry Dam is a buttress dam on the Varahina-South River, a tributary of the Ikopa River, near Tsiazompaniry in the Analamanga Region of Madagascar. The dam was constructed by a French firm in 1956. It creates Lake Tsiazompaniry, the largest reservoir in the country, which has a surface area of 31 km2 (12 sq mi) and a storage volume of 260,000,000 m3 (210,000 acre⋅ft). A second buttress dam, 1 km (0.62 mi) northwest of the main dam helps withhold the reservoir. Water released from the dam supplies a regulated flow to hydroelectric power station at the Antelomita Dam downstream. Efforts to install a 5.25 MW power station at the base of the dam began in 2011. (Full article...)
The Capanda Dam is a hydroelectric dam on the Kwanza River in Malanje Province, Angola. Built in 1987–2007 by the Russian company Tekhnopromexport, general designer - the institute Hydroproject (Chief Engineer - Ph.D Fedosov V.E.) The facility generates power by utilizing four turbines and 130 megawatts (170,000 hp) each, totalling the installed capacity to 520 megawatts (700,000 hp) . Total cost of US$4 billion. An additional cost of more than US$400 million was spent in repairing the damage caused during UNITA's occupation of the area at the time of the Angolan Civil War in 1992 and 1999. (Full article...)
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The Sidi El Barrak Dam is an embankment dam centred 18 km (11 mi) northeast of Tabarka and 2 km (1 mi) from the Mediterranean Sea on the Oued Zouara River in the Beja Governorate, Tunisia. Constructed between 1994 and 2000, the primary purpose of the dam is water supply. As part of the Sidi el Barrak Development Project, water stored in the dam is pumped to the Seyjame Dam, at a rate of 265,000,000 m3 (214,839 acre⋅ft) annually. This water is supplied to Tunis, Cap Bon and the Sahel including Sfax for municipal use as well as agricultural purposes. The entire project was completed in 2002. (Full article...)
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The Gilgel Gibe III Dam is a 250m high roller-compacted concrete dam with an associated hydroelectric power plant on the Omo River in Ethiopia. It is located about 62 km (39 mi) west of Sodo in the Southern Nations, Nationalities, and Peoples' Region. Once fully commissioned, it will be the third largest hydroelectric plant in Africa with a power output of about 1,870 Megawatt (MW), thus more than doubling total installed capacity in Ethiopia from its 2007 level of 814 MW. The Gibe III dam is part of the Gibe cascade, a series of dams including the existing Gibe I dam (184 MW) and Gibe II power station (420 MW) as well as the planned Gibe IV (1,472 MW) and Gibe V (560 MW) dams. The existing dams are owned and operated by the state-owned Ethiopian Electric Power, which is also the client for the Gibe III Dam.
The US$1.8 billion project began in 2006 and electricity generation started in October 2015. The remaining generators were operational by 2016. The project has experienced serious delays; in May 2012, full commissioning had been scheduled for June 2013. The dam was inaugurated by Prime Minister Hailemariam Desalegn on 17 December 2016.
Local and international environmental groups forecast major negative environmental and social impacts of the dam and criticized the project's environmental and social impact assessment as insufficient. Because of this and accusations that the entire approval process for the project was suspect, funding for the full construction cost was not secured, as the African Development Bank delayed a decision about a loan pending a review of the dam's environmental impact by its compliance review and mediation unit. This dates back to August 2009 when they accepted a call from NGOs for such a review. In August 2010 Ethiopian Prime Minister Meles Zenawi vowed to complete the dam "at any cost", saying the dam's critics "don’t want to see developed Africa; they want us to remain undeveloped and backward to serve their tourists as a museum." (Full article...)
The Al Massira Dam is a gravity dam located 70 kilometres (43 mi) south of Settat on the Oum Er-Rbia River in Settat Province, Morocco. Completed in 1979, the dam provides water for the irrigation of over 100,000 hectares (250,000 acres) of farmland in the Doukkala region. The dam's hydroelectric power plant also generates 221 gigawatt-hours (800 TJ) on average annually. The power station was commissioned in 1980. Just north of the dam is a rip rap saddle dam that supports water elevation in the reservoir. The dam's reservoir and wetlands were designated as a Ramsar site in 2005.
In 2024 analysis of satellite images of the dam by the BBC revealed the volume of water was 3% of the amount present nine years previously. The country had suffered from six consecutive years of drought. The Moroccan water ministry told the BBC that use of the dam's water for irrigating farmland had been suspended since 2021, the water being reserved for supplying cities such as Casablanca and Marrakesh. Many of the springs in the Middle Atlas mountains, which feed the reservoir, had dried-up. Reduced snowfall at higher altitude had also contributed to less meltwater flowing into the streams feeding the dam. In August 2023 Morocco recorded a record highest-ever temperature of 50.4C which caused an increase in evaporation, adding to a reduction in water's level. (Full article...)
The syndicate had originally approached veteran comic strip creators Milton Caniff and Noel Sickles about doing a Bruce Lee strip in 1978. The project never got off the ground, and five years later the syndicate tried again.
Intended for "downscale, . . . very young audiences", The Legend of Bruce Lee was intended to "help boost newspaper circulation by attracting younger or less well-educated readers who don't normally read newspapers". It was written by Sharman DiVono (who herself had martial arts training), and illustrated by Fran Matera (with uncredited assists from Dick Kulpa). (Full article...)
The player controls Thomas, the titular Kung-Fu Master, as he fights his way through the five levels of the Devil's Temple to rescue his girlfriend Sylvia from the crime boss Mr. X. As he ascends the tower, he has to fight many enemies along the way and five end-of-level boss battles, a concept inspired by Game of Death. Thomas and each boss have a health meter, and the game temporarily becomes a one-on-one fighting game during boss battles.
The game was a major commercial success, topping the Japanese arcade charts and becoming America's second highest-grossing arcade game of 1985, while receiving critical acclaim for its fast-paced, side-scrolling gameplay and detailed, colorful graphics. A port for the Nintendo Entertainment System (known as the Famicom in Japan) was developed by Nintendo under the direction of Shigeru Miyamoto, released as Spartan X in Japan and Kung-Fu in the West, selling 3.5 million copies worldwide. It was also one of the top five best-selling Commodore 64 games of 1986. It spawned the sequel Spartan X 2 (1991) and the spiritual successors Trojan (1986) and Vigilante (1988). (Full article...)
Bruce Le (simplified Chinese: 吕小龙; traditional Chinese: 呂小龍; pinyin: Lǚ Xiǎolóng; born June 5, 1950) is a martial artist and actor known for his martial arts film of the 1970s and 1980s. Most of these were inexpensively produced and were made to capitalise on the martial arts phenomenon started by Bruce Lee, whose death in 1973 left a large box office void (hence the name change to "Bruce Le").
Dragon Lee (born 1958) is an actor and practitioner of taekwondo and hapkido. He made a name for himself as a martial arts film star in the 1970s and 80s. His birth name is Moon Kyung-seok, but he is also called Keo Ryong (literally "giant dragon") in South Korea.
When Dragon Lee was at a theater, a man told him that he resembled Bruce Lee, a big compliment because Bruce Lee was popular at the time. The man knew film directors in Hong Kong and helped Dragon Lee advance his career. (Full article...)
Initially released for Sega platforms, Dragon: The Bruce Lee Story was later ported to the Atari Jaguar and Super Nintendo Entertainment System, each one featuring several changes and additions compared with the original version while both the Game Gear and Master System versions, which were also released in 1994, feature an entirely different gameplay format.
Since its release, Dragon: The Bruce Lee Story garnered mostly negative reviews, with criticism directed at the slow-paced and shallow gameplay. (Full article...)
The Legend of Bruce Lee (Chinese: 李小龍傳奇) is a 2008 Chinese biographical television series based on the life story of martial artist and actor Bruce Lee. The 50-episode series was produced and broadcast by CCTV and began airing on October 12, 2008. It was intended to promote Chinese culture alongside the 2008 Beijing Summer Olympics.
It stars Hong Kong actor Danny Chan as Bruce Lee and American actress Michelle Lang as Lee's wife, Linda Lee Cadwell. The production period spanned nine months, with filming taking place in China, Hong Kong, Macau, the United States, Italy, and Thailand, and with a budget of 50 million yuan (US$7.3 million).
Ip Man (born Ip Kai-man; 1 October 1893 – 2 December 1972), also known as Yip Man, was a Chinese martial artist. He became a teacher of the martial art of Wing Chun when he was 20. He had several students who later became martial arts masters in their own right, the most famous among them being Bruce Lee. (Full article...)
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Lee in 2019
Shannon Emery Lee Keasler (born April 19, 1969) is an American actress, businesswoman, singer, and martial artist. She is the only living child of actor and martial artist Bruce Lee and retired martial arts teacher Linda Lee Cadwell, and is the younger sister of actor Brandon Lee. Through Bruce Lee she is a granddaughter of Cantonese opera singer and film actor Lee Hoi-chuen. (Full article...)
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Leung Siu-lung in 2007
Bruce Liang (28 April 1948) is a Hong Kong martial artist and actor who has appeared in many Hong Kong martial arts movies. He often appeared billed as "Bruce Leung", "Bruce Liang", "Bruce Leong", or "Bruce Leung Siu-lung", and is thus generally grouped among the Bruce Lee clones that sprang up after Lee's death in the subgenre known as Bruceploitation. (Full article...)
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Bruce Lai, real name Chang Yi-tao (1950 – 2014), was a Hong Kong actor who starred in many Godfrey Ho films.
Chinese Gung Fu: The Philosophical Art of Self-Defense was published in early 1963 by Bruce Lee with the help of friend and fellow martial artist James Yimm Lee of Oakland, California. James had previously published books on the martial arts such as Modern Gung Fu, Karate: Iron, Poison Hand Training and Karate Oriental Self-Defense in 1957. In the book Remembering the Master: Bruce Lee, James Yimm Lee and the Creation of Jeet Kune Do by Sid Campbell and Greglon Yimm Lee (James Lee's son) it is stated the initial run was 1,500 copies. The book was sold through James Lee's company Oriental Book Sales at a price of $5. In addition to the book, a companion Chinese Gung Fu instruction chart was available for $1.
Following Bruce Lee's death, his estate commissioned writer John Little to edit and publish some of Lee's writings. Little included the content of Chinese Gung Fu: The Philosophical Art of Self-Defense as well as additional 1964 writings by Bruce Lee in the book Bruce Lee, The Tao of Gung Fu: Commentaries on the Chinese Martial Arts. (Full article...)
The Game of Death (Chinese: 死亡的遊戲) is an incomplete Hong Kong martial arts film, of which portions were filmed between September and October 1972, directed, written, produced by and starring Bruce Lee. The project was paused to film and produce Enter the Dragon. For The Game of Death, over 120 minutes of footage was shot, which was later misplaced in the Golden Harvest archives. The remaining footage has since been released with Lee's original Cantonese and English dialogue, with John Little dubbing Lee's Hai Tien character as part of the documentary titled Bruce Lee: A Warrior's Journey. Much of the footage that was shot is from what was to be the climax of the film.
During filming, Lee received an offer to star in Enter the Dragon, the first kung fu film to be produced by a Hollywood studio (Warner Bros.), and with a budget unprecedented for the genre ($850,000). Lee died of cerebral edema before the film's release. At the time of his death, he had made plans to resume the filming of The Game of Death. After Lee's death, Enter the Dragon director Robert Clouse was enlisted to finish the film using two stand-ins; it was released in 1978 as Game of Death, five years after Lee's death, by Golden Harvest.
The story of Lee's original 1972 film involves Lee's character, in order to save his younger sister and brother, joining a group of martial artists who are hired to retrieve a stolen Chinese national treasure[need quotation to verify] from the top floor of a five-story pagoda in South Korea, with each floor guarded by martial artists who must be defeated while ascending the tower.[additional citation(s) needed] The 1978 film's plot was altered to a revenge story, where the mafia attempts to kill Lee's character, who fakes his death and seeks vengeance against those who tried to kill him. The final part of the film uses some of Lee's original film footage, but with the pagoda setting changed to a restaurant building, where he fights martial artists hired by the mafia in an attempt to rescue his fiancée Ann Morris (played by Colleen Camp). This revised version received a mixed critical reception but was commercially successful, grossing an estimated US$50,000,000 (equivalent to $230,000,000 in 2023) worldwide. (Full article...)
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Bruce Lee was a 1994 six-issue comic book miniseries published by Malibu Comics and written by Mike Baron and illustrated by Val Mayerik. It focused on a fictional Bruce Lee character striving his way through gangs and rival dojo owners, while building a movie career. Malibu included a Mortal Kombat short story in the first and fifth issues.
Writer Mike Baron had previously written three issues of the Green Hornet comic published by NOW Comics, about Lee's Kato in the 1966 TV show. Val Mayerik had previously illustrated the second Kato limited series (also published by NOW). Baron states inspiration for the comic came from the 1970s Marvel Comics series Shang-Chi: Master of Kung Fu.
Titan Books collected the miniseries into a trade paperback, simply titled Bruce Lee, in 1995. The publisher Edizioni Star Comics translated the series into Italian for its ongoing series Mortal Kombat & Bruce Lee, published in 1995–1996. (Full article...)
Announced in July 2017, it is the first Tarantino film not to involve Bob and Harvey Weinstein, as Tarantino ended his partnership with the brothers following the sexual abuse allegations against the latter. After a bidding war, the film was distributed by Sony Pictures, which met Tarantino's demands including final cut privilege. Pitt, DiCaprio, Robbie, Zoë Bell, Kurt Russell, and others joined the cast between January and June 2018. Principal photography lasted from June through November around Los Angeles. Once Upon a Time in Hollywood is the final film to feature Luke Perry, who died on March 4, 2019, and it is dedicated to his memory.
Once Upon a Time in Hollywood premiered at the 2019 Cannes Film Festival on May 21, 2019, and was theatrically released in the United States on July 26, 2019, and in the United Kingdom on August 14. It grossed $374 million worldwide and received praise from critics for Tarantino's direction and screenplay, the performances (particularly from DiCaprio and Pitt), cinematography, soundtrack, sound design, costume design, and production values. The National Board of Review and the American Film Institute named Once Upon a Time in Hollywood one of the top-ten films of 2019. Once Upon a Time in Hollywood was nominated for ten awards at the 92nd Academy Awards, winning two, and received numerous other accolades. A novelization, written by Tarantino in his debut as an author, was published on June 29, 2021. (Full article...)
The Way of the Dragon was released in Hong Kong on 30 December 1972, and in the United States in August 1974. The film went on to gross an estimated US$130 million worldwide (equivalent to over $700 million adjusted for inflation), against a tight budget of $130,000, earning a thousand times its budget. It was the highest-grossing Hong Kong film up until Lee's next film Enter the Dragon (1973).
The film is primarily set in a restaurant in Rome. The owners are being harassed by a local crime boss, and request help from a relative in Hong Kong. The help arrives in the form of a young martial artist. The conflict between the restaurant staff and the gangsters soon escalates. (Full article...)
Bruce Lee is a platform game written by Ron J. Fortier for Atari 8-bit computers and published in 1984 by Datasoft. The graphics are by Kelly Day and music by John A. Fitzpatrick. The player takes the role of Bruce Lee, while a second player controls either Yamo or alternates with player one for control of Bruce Lee.
Commodore 64 and Apple II versions were released the same year. The game was converted to the ZX Spectrum and Amstrad CPC and published by U.S. Gold. It was the first U.S. Gold release featuring a famous individual. An MSX version was published in 1985 by Comptiq. (Full article...)
Bruce Lee was a 1994 six-issue comic book miniseries published by Malibu Comics and written by Mike Baron and illustrated by Val Mayerik. It focused on a fictional Bruce Lee character striving his way through gangs and rival dojo owners, while building a movie career. Malibu included a Mortal Kombat short story in the first and fifth issues.
Writer Mike Baron had previously written three issues of the Green Hornet comic published by NOW Comics, about Lee's Kato in the 1966 TV show. Val Mayerik had previously illustrated the second Kato limited series (also published by NOW). Baron states inspiration for the comic came from the 1970s Marvel Comics series Shang-Chi: Master of Kung Fu.
Titan Books collected the miniseries into a trade paperback, simply titled Bruce Lee, in 1995. The publisher Edizioni Star Comics translated the series into Italian for its ongoing series Mortal Kombat & Bruce Lee, published in 1995–1996. (Full article...)
Tao of Jeet Kune Do is a book expressing Bruce Lee's martial artsphilosophy and viewpoints, published posthumously (after Bruce Lee's death in 1973). The project for this book began in 1970 when Bruce Lee suffered a back injury during one of his practice sessions. During this time he could not train in martial arts. He was ordered by his doctors to wear a back brace for 6 months in order to recover from his injury. This was a very tiring and dispiriting time for Lee who was always very physically active.
It was during his convalescence that he decided to compile a treatise on the system or approach to martial arts that he was developing; he called it Jeet Kune Do. The bulk of these writings would become the "core set of writings". Many of these writings were done during a single session which provided natural continuity. Lee had also kept various notes throughout the development of his combat philosophy and these would become the disparate notes used in the book. Many of these notes were "sudden inspirations" which were incomplete and lacked any kind of a construct. The combination of the "core set of writings" and the "disparate notes" would be known as the text Tao of Jeet Kune Do.
In 1971, it was Lee's intent to finish the treatise that he started during his convalescence. However, his film career and work prevented him from doing so. He also vacillated about publishing his book as he felt that this work might be used for the wrong purposes. Lee's intent in writing the book was to record one man's way of thinking about the martial arts. It was to be a guidebook, not a set of instructions or "How to" manual to learn martial arts. (Full article...)
The version of the film that is commonly distributed in the West (USA) on public domain-type DVD and video labels runs 93 minutes in length. The British VHS-version released in 1979 runs 118 minutes. (Full article...)
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Wong Shun-leung (Chinese: 黃淳樑; pinyin: Huang Chunliáng; Jyutping: Wong4 Seon4-loeng4; 8 May 1935 – 28 January 1997)[a] was a Hong Kong martial artist who studied Wing Chunkung fu under Yip Man (葉問) and was credited with training Bruce Lee. In interviews, Wong claimed to have won at least 60, and perhaps over 100, street fights against martial artists of various styles, though these numbers cannot be independently confirmed. Due to his reputation, his students and admirers referred to him as 'Gong Sau Wong' (講手王 or 'King of Talking Hands'). Wong recorded one instructional film entitled Wing Chun: The science of in-fighting. (Full article...)
In April 2019, Cinemax renewed the series for a second season which premiered on October 2, 2020. It was Cinemax's final series before ceasing production of original programming. In April 2021, the series was renewed for a third season, along with the announcement that the series would move to HBO Max, later rebranded to Max. The third season premiered on Max on June 29, 2023. In December 2023, the series was canceled after three seasons. (Full article...)
A statue of Bruce Lee was unveiled on 26 November 2005, in the city of Mostar, Bosnia and Herzegovina, by sculptor Ivan Fijolić. Located in Zrinjevac City Park, the life-sized statue stands 1.68 m (5 ft 6 in) tall, shorter than Bruce Lee's actual height of 1.72 m (5 ft 8 in), and was a symbol of solidarity in the ethnically-divided city until it was stolen in a heist on March 4, 2024, and was subsequently found albeit cut in pieces. (Full article...)
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Bruce Lee: The Lost Interview is the name given to the 9 December 1971 edition of The Pierre Berton Show, which featured martial artist/actor Bruce Lee in his only English speaking television interview. Its title is derived from its status; it was presumed lost for several years until its rediscovery and airing on 2 November 1994. Over the course of the interview, which was filmed in Hong Kong, Bruce Lee and Pierre Berton discuss Lee's career, various aspects of martial arts philosophy and the inherent problems faced by an Asian in pursuing stardom in Hollywood. A review of the interview by Bill Stockey said that Bruce Lee's "human side is exposed and he is portrayed as more approachable". (Full article...)
Kato is a fictional character from The Green Hornet franchise. This character has appeared with the Green Hornet in radio, film, television, book and comic book versions. Kato is the Green Hornet's crime-fighting sidekick, and Britt Reid's manservant in civilian life, and has been played by a number of actors. On radio, Kato was initially played by Raymond Hayashi, then Roland Parker who had the role for most of the run, and in the later years Mickey Tolan and Paul Carnegie. Keye Luke took the role in the movie serials, and in the television series, he was portrayed by Bruce Lee. Jay Chou played Kato in the 2011 Green Hornet film. (Full article...)
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The Legend of Bruce Lee (Chinese: 李小龍傳奇) is a 2008 Chinese biographical television series based on the life story of martial artist and actor Bruce Lee. The 50-episode series was produced and broadcast by CCTV and began airing on October 12, 2008. It was intended to promote Chinese culture alongside the 2008 Beijing Summer Olympics.
It stars Hong Kong actor Danny Chan as Bruce Lee and American actress Michelle Lang as Lee's wife, Linda Lee Cadwell. The production period spanned nine months, with filming taking place in China, Hong Kong, Macau, the United States, Italy, and Thailand, and with a budget of 50 million yuan (US$7.3 million).
An atmospheric diving suit (ADS) is a small one-person articulated submersible which resembles a suit of armour, with elaborate pressure joints to allow articulation while maintaining an internal pressure of one atmosphere. An ADS can enable diving at depths of up to 2,300 feet (700 m) for many hours by eliminating the majority of significant physiological dangers associated with deep diving. The occupant of an ADS does not need to decompress, and there is no need for special breathing gas mixtures, so there is little danger of decompression sickness or nitrogen narcosis when the ADS is functioning properly. An ADS can permit less skilled swimmers to complete deep dives, albeit at the expense of dexterity.
Atmospheric diving suits in current use include the Newtsuit, Exosuit, Hardsuit and the WASP, all of which are self-contained hard suits that incorporate propulsion units. The Hardsuit is constructed from cast aluminum (forged aluminum in a version constructed for the US Navy for submarine rescue); the upper hull is made from cast aluminum, while the bottom dome is machined aluminum. The WASP is of glass-reinforced plastic (GRP) body tube construction. (Full article...)
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Surface-supplied diving is a mode of underwater diving using equipment supplied with breathing gas through a diver's umbilical from the surface, either from the shore or from a diving support vessel, sometimes indirectly via a diving bell. This is different from scuba diving, where the diver's breathing equipment is completely self-contained and there is no essential link to the surface. The primary advantages of conventional surface supplied diving are lower risk of drowning and considerably larger breathing gas supply than scuba, allowing longer working periods and safer decompression. Disadvantages are the absolute limitation on diver mobility imposed by the length of the umbilical, encumbrance by the umbilical, and high logistical and equipment costs compared with scuba. The disadvantages restrict use of this mode of diving to applications where the diver operates within a small area, which is common in commercial diving work.
Airline, or hookah diving, and "compressor diving" are lower technology variants also using a breathing air supply from the surface. (Full article...)
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Scuba diving is a mode of underwater diving whereby divers use breathing equipment that is completely independent of a surface breathing gas supply, and therefore has a limited but variable endurance. The name scuba is an anacronym for "Self-Contained Underwater Breathing Apparatus" and was coined by Christian J. Lambertsen in a patent submitted in 1952. Scuba divers carry their own source of breathing gas, usually compressed air, affording them greater independence and movement than surface-supplied divers, and more time underwater than free divers. Although the use of compressed air is common, a gas blend with a higher oxygen content, known as enriched air or nitrox, has become popular due to the reduced nitrogen intake during long or repetitive dives. Also, breathing gas diluted with helium may be used to reduce the effects of nitrogen narcosis during deeper dives.
Open-circuit scuba systems discharge the breathing gas into the environment as it is exhaled, and consist of one or more diving cylinders containing breathing gas at high pressure which is supplied to the diver at ambient pressure through a diving regulator. They may include additional cylinders for range extension, decompression gas or emergency breathing gas. Closed-circuit or semi-closed circuit rebreather scuba systems allow recycling of exhaled gases. The volume of gas used is reduced compared to that of open-circuit, so a smaller cylinder or cylinders may be used for an equivalent dive duration. Rebreathers extend the time spent underwater compared to open-circuit for the same metabolic gas consumption; they produce fewer bubbles and less noise than open-circuit scuba, which makes them attractive to covert military divers to avoid detection, scientific divers to avoid disturbing marine animals, and media divers to avoid bubble interference.
Scuba diving may be done recreationally or professionally in a number of applications, including scientific, military and public safety roles, but most commercial diving uses surface-supplied diving equipment when this is practicable. Scuba divers engaged in armed forces covert operations may be referred to as frogmen, combat divers or attack swimmers.
Underwater diving, as a human activity, is the practice of descending below the water's surface to interact with the environment. It is also often referred to as diving, an ambiguous term with several possible meanings, depending on context. Immersion in water and exposure to high ambient pressure have physiological effects that limit the depths and duration possible in ambient pressure diving. Humans are not physiologically and anatomically well-adapted to the environmental conditions of diving, and various equipment has been developed to extend the depth and duration of human dives, and allow different types of work to be done.
In ambient pressure diving, the diver is directly exposed to the pressure of the surrounding water. The ambient pressure diver may dive on breath-hold (freediving) or use breathing apparatus for scuba diving or surface-supplied diving, and the saturation diving technique reduces the risk of decompression sickness (DCS) after long-duration deep dives. Atmospheric diving suits (ADS) may be used to isolate the diver from high ambient pressure. Crewed submersibles can extend depth range to full ocean depth, and remotely controlled or robotic machines can reduce risk to humans.
The environment exposes the diver to a wide range of hazards, and though the risks are largely controlled by appropriate diving skills, training, types of equipment and breathing gases used depending on the mode, depth and purpose of diving, it remains a relatively dangerous activity. Professional diving is usually regulated by occupational health and safety legislation, while recreational diving may be entirely unregulated. Diving activities are restricted to maximum depths of about 40 metres (130 ft) for recreational scuba diving, 530 metres (1,740 ft) for commercial saturation diving, and 610 metres (2,000 ft) wearing atmospheric suits. Diving is also restricted to conditions which are not excessively hazardous, though the level of risk acceptable can vary, and fatal incidents may occur.
Recreational diving (sometimes called sport diving or subaquatics) is a popular leisure activity. Technical diving is a form of recreational diving under more challenging conditions. Professional diving (commercial diving, diving for research purposes, or for financial gain) involves working underwater. Public safety diving is the underwater work done by law enforcement, fire rescue, and underwater search and recovery dive teams. Military diving includes combat diving, clearance diving and ships husbandry. Deep sea diving is underwater diving, usually with surface-supplied equipment, and often refers to the use of standard diving dress with the traditional copper helmet. Hard hat diving is any form of diving with a helmet, including the standard copper helmet, and other forms of free-flow and lightweight demand helmets. The history of breath-hold diving goes back at least to classical times, and there is evidence of prehistoric hunting and gathering of seafoods that may have involved underwater swimming. Technical advances allowing the provision of breathing gas to a diver underwater at ambient pressure are recent, and self-contained breathing systems developed at an accelerated rate following the Second World War. (Full article...)
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Surface-supplied diving is a mode of underwater diving using equipment supplied with breathing gas through a diver's umbilical from the surface, either from the shore or from a diving support vessel, sometimes indirectly via a diving bell. This is different from scuba diving, where the diver's breathing equipment is completely self-contained and there is no essential link to the surface. The primary advantages of conventional surface supplied diving are lower risk of drowning and considerably larger breathing gas supply than scuba, allowing longer working periods and safer decompression. Disadvantages are the absolute limitation on diver mobility imposed by the length of the umbilical, encumbrance by the umbilical, and high logistical and equipment costs compared with scuba. The disadvantages restrict use of this mode of diving to applications where the diver operates within a small area, which is common in commercial diving work.
Airline, or hookah diving, and "compressor diving" are lower technology variants also using a breathing air supply from the surface. (Full article...)
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Underwater diving, as a human activity, is the practice of descending below the water's surface to interact with the environment. It is also often referred to as diving, an ambiguous term with several possible meanings, depending on context. Immersion in water and exposure to high ambient pressure have physiological effects that limit the depths and duration possible in ambient pressure diving. Humans are not physiologically and anatomically well-adapted to the environmental conditions of diving, and various equipment has been developed to extend the depth and duration of human dives, and allow different types of work to be done.
In ambient pressure diving, the diver is directly exposed to the pressure of the surrounding water. The ambient pressure diver may dive on breath-hold (freediving) or use breathing apparatus for scuba diving or surface-supplied diving, and the saturation diving technique reduces the risk of decompression sickness (DCS) after long-duration deep dives. Atmospheric diving suits (ADS) may be used to isolate the diver from high ambient pressure. Crewed submersibles can extend depth range to full ocean depth, and remotely controlled or robotic machines can reduce risk to humans.
The environment exposes the diver to a wide range of hazards, and though the risks are largely controlled by appropriate diving skills, training, types of equipment and breathing gases used depending on the mode, depth and purpose of diving, it remains a relatively dangerous activity. Professional diving is usually regulated by occupational health and safety legislation, while recreational diving may be entirely unregulated. Diving activities are restricted to maximum depths of about 40 metres (130 ft) for recreational scuba diving, 530 metres (1,740 ft) for commercial saturation diving, and 610 metres (2,000 ft) wearing atmospheric suits. Diving is also restricted to conditions which are not excessively hazardous, though the level of risk acceptable can vary, and fatal incidents may occur.
Recreational diving (sometimes called sport diving or subaquatics) is a popular leisure activity. Technical diving is a form of recreational diving under more challenging conditions. Professional diving (commercial diving, diving for research purposes, or for financial gain) involves working underwater. Public safety diving is the underwater work done by law enforcement, fire rescue, and underwater search and recovery dive teams. Military diving includes combat diving, clearance diving and ships husbandry. Deep sea diving is underwater diving, usually with surface-supplied equipment, and often refers to the use of standard diving dress with the traditional copper helmet. Hard hat diving is any form of diving with a helmet, including the standard copper helmet, and other forms of free-flow and lightweight demand helmets. The history of breath-hold diving goes back at least to classical times, and there is evidence of prehistoric hunting and gathering of seafoods that may have involved underwater swimming. Technical advances allowing the provision of breathing gas to a diver underwater at ambient pressure are recent, and self-contained breathing systems developed at an accelerated rate following the Second World War. (Full article...)
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Surface-supplied diving is a mode of underwater diving using equipment supplied with breathing gas through a diver's umbilical from the surface, either from the shore or from a diving support vessel, sometimes indirectly via a diving bell. This is different from scuba diving, where the diver's breathing equipment is completely self-contained and there is no essential link to the surface. The primary advantages of conventional surface supplied diving are lower risk of drowning and considerably larger breathing gas supply than scuba, allowing longer working periods and safer decompression. Disadvantages are the absolute limitation on diver mobility imposed by the length of the umbilical, encumbrance by the umbilical, and high logistical and equipment costs compared with scuba. The disadvantages restrict use of this mode of diving to applications where the diver operates within a small area, which is common in commercial diving work.
Airline, or hookah diving, and "compressor diving" are lower technology variants also using a breathing air supply from the surface. (Full article...)
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Freediving, free-diving, free diving, breath-hold diving, or skin diving, is a mode of underwater diving that relies on breath-holding until resurfacing rather than the use of breathing apparatus such as scuba gear.
Besides the limits of breath-hold, immersion in water and exposure to high ambient pressure also have physiological effects that limit the depths and duration possible in freediving.
Surface-supplied diving is a mode of underwater diving using equipment supplied with breathing gas through a diver's umbilical from the surface, either from the shore or from a diving support vessel, sometimes indirectly via a diving bell. This is different from scuba diving, where the diver's breathing equipment is completely self-contained and there is no essential link to the surface. The primary advantages of conventional surface supplied diving are lower risk of drowning and considerably larger breathing gas supply than scuba, allowing longer working periods and safer decompression. Disadvantages are the absolute limitation on diver mobility imposed by the length of the umbilical, encumbrance by the umbilical, and high logistical and equipment costs compared with scuba. The disadvantages restrict use of this mode of diving to applications where the diver operates within a small area, which is common in commercial diving work.
Airline, or hookah diving, and "compressor diving" are lower technology variants also using a breathing air supply from the surface. (Full article...)
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Rebreather diving is underwater diving using diving rebreathers, a class of underwater breathing apparatus which recirculate the breathing gas exhaled by the diver after replacing the oxygen used and removing the carbon dioxide metabolic product. Rebreather diving is practiced by recreational, military and scientific divers in applications where it has advantages over open circuit scuba, and surface supply of breathing gas is impracticable. The main advantages of rebreather diving are extended gas endurance, low noise levels, and lack of bubbles.
Rebreathers are generally used for scuba applications, but are also occasionally used for bailout systems for surface-supplied diving. Gas reclaim systems used for deep heliox diving use similar technology to rebreathers, as do saturation divinglife-support systems, but in these applications the gas recycling equipment is not carried by the diver. Atmospheric diving suits also carry rebreather technology to recycle breathing gas as part of the life-support system, but this article covers the procedures of ambient pressure diving using rebreathers carried by the diver.
Rebreathers are generally more complex to use than open circuit scuba, and have more potential points of failure, so acceptably safe use requires a greater level of skill, attention and situational awareness, which is usually derived from understanding the systems, diligent maintenance and overlearning the practical skills of operation and fault recovery. Fault tolerant design can make a rebreather less likely to fail in a way that immediately endangers the user, and reduces the task loading on the diver which in turn may lower the risk of operator error. (Full article...)
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Saturation diving is diving for periods long enough to bring all tissues into equilibrium with the partial pressures of the inert components of the breathing gas used. It is a diving mode that reduces the number of decompressions divers working at great depths must undergo by only decompressing divers once at the end of the diving operation, which may last days to weeks, having them remain under pressure for the whole period. A diver breathing pressurized gas accumulates dissolved inert gas used in the breathing mixture to dilute the oxygen to a non-toxic level in the tissues, which can cause potentially fatal decompression sickness ("the bends") if permitted to come out of solution within the body tissues; hence, returning to the surface safely requires lengthy decompression so that the inert gases can be eliminated via the lungs. Once the dissolved gases in a diver's tissues reach the saturation point, however, decompression time does not increase with further exposure, as no more inert gas is accumulated.
Saturation diving takes advantage of this by having divers remain in that saturated state. When not in the water, the divers live in a sealed environment which maintains their pressurised state; this can be an ambient pressure underwater habitat or a saturation system at the surface, with transfer to and from the pressurised living quarters to the equivalent depth underwater via a closed, pressurised diving bell. This may be maintained for up to several weeks, and divers are decompressed to surface pressure only once, at the end of their tour of duty. By limiting the number of decompressions in this way, and using a conservative decompression schedule the risk of decompression sickness is significantly reduced, and the total time spent decompressing is minimised. Saturation divers typically breathe a helium–oxygen mixture to prevent nitrogen narcosis, and limit work of breathing, but at shallow depths saturation diving has been done on nitrox mixtures.
Most of the physiological and medical aspects of diving to the same depths are much the same in saturation and bell-bounce ambient pressure diving, or are less of a problem, but there are medical and psychological effects of living under saturation for extended periods.
Saturation diving is a specialized form of diving; of the 3,300 commercial divers employed in the United States in 2015, 336 were saturation divers. Special training and certification is required, as the activity is inherently hazardous, and a set of standard operating procedures, emergency procedures, and a range of specialised equipment is used to control the risk, that require consistently correct performance by all the members of an extended diving team. The combination of relatively large skilled personnel requirements, complex engineering, and bulky, heavy equipment required to support a saturation diving project make it an expensive diving mode, but it allows direct human intervention at places that would not otherwise be practical, and where it is applied, it is generally more economically viable than other options, if such exist. (Full article...)
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Surface-supplied diving is a mode of underwater diving using equipment supplied with breathing gas through a diver's umbilical from the surface, either from the shore or from a diving support vessel, sometimes indirectly via a diving bell. This is different from scuba diving, where the diver's breathing equipment is completely self-contained and there is no essential link to the surface. The primary advantages of conventional surface supplied diving are lower risk of drowning and considerably larger breathing gas supply than scuba, allowing longer working periods and safer decompression. Disadvantages are the absolute limitation on diver mobility imposed by the length of the umbilical, encumbrance by the umbilical, and high logistical and equipment costs compared with scuba. The disadvantages restrict use of this mode of diving to applications where the diver operates within a small area, which is common in commercial diving work.
Airline, or hookah diving, and "compressor diving" are lower technology variants also using a breathing air supply from the surface. (Full article...)
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Surface-supplied diving is a mode of underwater diving using equipment supplied with breathing gas through a diver's umbilical from the surface, either from the shore or from a diving support vessel, sometimes indirectly via a diving bell. This is different from scuba diving, where the diver's breathing equipment is completely self-contained and there is no essential link to the surface. The primary advantages of conventional surface supplied diving are lower risk of drowning and considerably larger breathing gas supply than scuba, allowing longer working periods and safer decompression. Disadvantages are the absolute limitation on diver mobility imposed by the length of the umbilical, encumbrance by the umbilical, and high logistical and equipment costs compared with scuba. The disadvantages restrict use of this mode of diving to applications where the diver operates within a small area, which is common in commercial diving work.
Airline, or hookah diving, and "compressor diving" are lower technology variants also using a breathing air supply from the surface. (Full article...)
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Scuba diving is a mode of underwater diving whereby divers use breathing equipment that is completely independent of a surface breathing gas supply, and therefore has a limited but variable endurance. The name scuba is an anacronym for "Self-Contained Underwater Breathing Apparatus" and was coined by Christian J. Lambertsen in a patent submitted in 1952. Scuba divers carry their own source of breathing gas, usually compressed air, affording them greater independence and movement than surface-supplied divers, and more time underwater than free divers. Although the use of compressed air is common, a gas blend with a higher oxygen content, known as enriched air or nitrox, has become popular due to the reduced nitrogen intake during long or repetitive dives. Also, breathing gas diluted with helium may be used to reduce the effects of nitrogen narcosis during deeper dives.
Open-circuit scuba systems discharge the breathing gas into the environment as it is exhaled, and consist of one or more diving cylinders containing breathing gas at high pressure which is supplied to the diver at ambient pressure through a diving regulator. They may include additional cylinders for range extension, decompression gas or emergency breathing gas. Closed-circuit or semi-closed circuit rebreather scuba systems allow recycling of exhaled gases. The volume of gas used is reduced compared to that of open-circuit, so a smaller cylinder or cylinders may be used for an equivalent dive duration. Rebreathers extend the time spent underwater compared to open-circuit for the same metabolic gas consumption; they produce fewer bubbles and less noise than open-circuit scuba, which makes them attractive to covert military divers to avoid detection, scientific divers to avoid disturbing marine animals, and media divers to avoid bubble interference.
Scuba diving may be done recreationally or professionally in a number of applications, including scientific, military and public safety roles, but most commercial diving uses surface-supplied diving equipment when this is practicable. Scuba divers engaged in armed forces covert operations may be referred to as frogmen, combat divers or attack swimmers.
Surface-supplied diving is a mode of underwater diving using equipment supplied with breathing gas through a diver's umbilical from the surface, either from the shore or from a diving support vessel, sometimes indirectly via a diving bell. This is different from scuba diving, where the diver's breathing equipment is completely self-contained and there is no essential link to the surface. The primary advantages of conventional surface supplied diving are lower risk of drowning and considerably larger breathing gas supply than scuba, allowing longer working periods and safer decompression. Disadvantages are the absolute limitation on diver mobility imposed by the length of the umbilical, encumbrance by the umbilical, and high logistical and equipment costs compared with scuba. The disadvantages restrict use of this mode of diving to applications where the diver operates within a small area, which is common in commercial diving work.
Airline, or hookah diving, and "compressor diving" are lower technology variants also using a breathing air supply from the surface. (Full article...)
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Surface-supplied diving is a mode of underwater diving using equipment supplied with breathing gas through a diver's umbilical from the surface, either from the shore or from a diving support vessel, sometimes indirectly via a diving bell. This is different from scuba diving, where the diver's breathing equipment is completely self-contained and there is no essential link to the surface. The primary advantages of conventional surface supplied diving are lower risk of drowning and considerably larger breathing gas supply than scuba, allowing longer working periods and safer decompression. Disadvantages are the absolute limitation on diver mobility imposed by the length of the umbilical, encumbrance by the umbilical, and high logistical and equipment costs compared with scuba. The disadvantages restrict use of this mode of diving to applications where the diver operates within a small area, which is common in commercial diving work.
Airline, or hookah diving, and "compressor diving" are lower technology variants also using a breathing air supply from the surface. (Full article...)
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Freediving, free-diving, free diving, breath-hold diving, or skin diving, is a mode of underwater diving that relies on breath-holding until resurfacing rather than the use of breathing apparatus such as scuba gear.
Besides the limits of breath-hold, immersion in water and exposure to high ambient pressure also have physiological effects that limit the depths and duration possible in freediving.
Surface-supplied diving is a mode of underwater diving using equipment supplied with breathing gas through a diver's umbilical from the surface, either from the shore or from a diving support vessel, sometimes indirectly via a diving bell. This is different from scuba diving, where the diver's breathing equipment is completely self-contained and there is no essential link to the surface. The primary advantages of conventional surface supplied diving are lower risk of drowning and considerably larger breathing gas supply than scuba, allowing longer working periods and safer decompression. Disadvantages are the absolute limitation on diver mobility imposed by the length of the umbilical, encumbrance by the umbilical, and high logistical and equipment costs compared with scuba. The disadvantages restrict use of this mode of diving to applications where the diver operates within a small area, which is common in commercial diving work.
Airline, or hookah diving, and "compressor diving" are lower technology variants also using a breathing air supply from the surface. (Full article...)
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Scuba diving is a mode of underwater diving whereby divers use breathing equipment that is completely independent of a surface breathing gas supply, and therefore has a limited but variable endurance. The name scuba is an anacronym for "Self-Contained Underwater Breathing Apparatus" and was coined by Christian J. Lambertsen in a patent submitted in 1952. Scuba divers carry their own source of breathing gas, usually compressed air, affording them greater independence and movement than surface-supplied divers, and more time underwater than free divers. Although the use of compressed air is common, a gas blend with a higher oxygen content, known as enriched air or nitrox, has become popular due to the reduced nitrogen intake during long or repetitive dives. Also, breathing gas diluted with helium may be used to reduce the effects of nitrogen narcosis during deeper dives.
Open-circuit scuba systems discharge the breathing gas into the environment as it is exhaled, and consist of one or more diving cylinders containing breathing gas at high pressure which is supplied to the diver at ambient pressure through a diving regulator. They may include additional cylinders for range extension, decompression gas or emergency breathing gas. Closed-circuit or semi-closed circuit rebreather scuba systems allow recycling of exhaled gases. The volume of gas used is reduced compared to that of open-circuit, so a smaller cylinder or cylinders may be used for an equivalent dive duration. Rebreathers extend the time spent underwater compared to open-circuit for the same metabolic gas consumption; they produce fewer bubbles and less noise than open-circuit scuba, which makes them attractive to covert military divers to avoid detection, scientific divers to avoid disturbing marine animals, and media divers to avoid bubble interference.
Scuba diving may be done recreationally or professionally in a number of applications, including scientific, military and public safety roles, but most commercial diving uses surface-supplied diving equipment when this is practicable. Scuba divers engaged in armed forces covert operations may be referred to as frogmen, combat divers or attack swimmers.
Underwater diving, as a human activity, is the practice of descending below the water's surface to interact with the environment. It is also often referred to as diving, an ambiguous term with several possible meanings, depending on context. Immersion in water and exposure to high ambient pressure have physiological effects that limit the depths and duration possible in ambient pressure diving. Humans are not physiologically and anatomically well-adapted to the environmental conditions of diving, and various equipment has been developed to extend the depth and duration of human dives, and allow different types of work to be done.
In ambient pressure diving, the diver is directly exposed to the pressure of the surrounding water. The ambient pressure diver may dive on breath-hold (freediving) or use breathing apparatus for scuba diving or surface-supplied diving, and the saturation diving technique reduces the risk of decompression sickness (DCS) after long-duration deep dives. Atmospheric diving suits (ADS) may be used to isolate the diver from high ambient pressure. Crewed submersibles can extend depth range to full ocean depth, and remotely controlled or robotic machines can reduce risk to humans.
The environment exposes the diver to a wide range of hazards, and though the risks are largely controlled by appropriate diving skills, training, types of equipment and breathing gases used depending on the mode, depth and purpose of diving, it remains a relatively dangerous activity. Professional diving is usually regulated by occupational health and safety legislation, while recreational diving may be entirely unregulated. Diving activities are restricted to maximum depths of about 40 metres (130 ft) for recreational scuba diving, 530 metres (1,740 ft) for commercial saturation diving, and 610 metres (2,000 ft) wearing atmospheric suits. Diving is also restricted to conditions which are not excessively hazardous, though the level of risk acceptable can vary, and fatal incidents may occur.
Recreational diving (sometimes called sport diving or subaquatics) is a popular leisure activity. Technical diving is a form of recreational diving under more challenging conditions. Professional diving (commercial diving, diving for research purposes, or for financial gain) involves working underwater. Public safety diving is the underwater work done by law enforcement, fire rescue, and underwater search and recovery dive teams. Military diving includes combat diving, clearance diving and ships husbandry. Deep sea diving is underwater diving, usually with surface-supplied equipment, and often refers to the use of standard diving dress with the traditional copper helmet. Hard hat diving is any form of diving with a helmet, including the standard copper helmet, and other forms of free-flow and lightweight demand helmets. The history of breath-hold diving goes back at least to classical times, and there is evidence of prehistoric hunting and gathering of seafoods that may have involved underwater swimming. Technical advances allowing the provision of breathing gas to a diver underwater at ambient pressure are recent, and self-contained breathing systems developed at an accelerated rate following the Second World War. (Full article...)
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Atmospheric diving suit
An atmospheric diving suit (ADS) is a small one-person articulated submersible which resembles a suit of armour, with elaborate pressure joints to allow articulation while maintaining an internal pressure of one atmosphere. An ADS can enable diving at depths of up to 2,300 feet (700 m) for many hours by eliminating the majority of significant physiological dangers associated with deep diving. The occupant of an ADS does not need to decompress, and there is no need for special breathing gas mixtures, so there is little danger of decompression sickness or nitrogen narcosis when the ADS is functioning properly. An ADS can permit less skilled swimmers to complete deep dives, albeit at the expense of dexterity.
Atmospheric diving suits in current use include the Newtsuit, Exosuit, Hardsuit and the WASP, all of which are self-contained hard suits that incorporate propulsion units. The Hardsuit is constructed from cast aluminum (forged aluminum in a version constructed for the US Navy for submarine rescue); the upper hull is made from cast aluminum, while the bottom dome is machined aluminum. The WASP is of glass-reinforced plastic (GRP) body tube construction. (Full article...)
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Surface-supplied diving is a mode of underwater diving using equipment supplied with breathing gas through a diver's umbilical from the surface, either from the shore or from a diving support vessel, sometimes indirectly via a diving bell. This is different from scuba diving, where the diver's breathing equipment is completely self-contained and there is no essential link to the surface. The primary advantages of conventional surface supplied diving are lower risk of drowning and considerably larger breathing gas supply than scuba, allowing longer working periods and safer decompression. Disadvantages are the absolute limitation on diver mobility imposed by the length of the umbilical, encumbrance by the umbilical, and high logistical and equipment costs compared with scuba. The disadvantages restrict use of this mode of diving to applications where the diver operates within a small area, which is common in commercial diving work.
Airline, or hookah diving, and "compressor diving" are lower technology variants also using a breathing air supply from the surface. (Full article...)
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Saturation diving is diving for periods long enough to bring all tissues into equilibrium with the partial pressures of the inert components of the breathing gas used. It is a diving mode that reduces the number of decompressions divers working at great depths must undergo by only decompressing divers once at the end of the diving operation, which may last days to weeks, having them remain under pressure for the whole period. A diver breathing pressurized gas accumulates dissolved inert gas used in the breathing mixture to dilute the oxygen to a non-toxic level in the tissues, which can cause potentially fatal decompression sickness ("the bends") if permitted to come out of solution within the body tissues; hence, returning to the surface safely requires lengthy decompression so that the inert gases can be eliminated via the lungs. Once the dissolved gases in a diver's tissues reach the saturation point, however, decompression time does not increase with further exposure, as no more inert gas is accumulated.
Saturation diving takes advantage of this by having divers remain in that saturated state. When not in the water, the divers live in a sealed environment which maintains their pressurised state; this can be an ambient pressure underwater habitat or a saturation system at the surface, with transfer to and from the pressurised living quarters to the equivalent depth underwater via a closed, pressurised diving bell. This may be maintained for up to several weeks, and divers are decompressed to surface pressure only once, at the end of their tour of duty. By limiting the number of decompressions in this way, and using a conservative decompression schedule the risk of decompression sickness is significantly reduced, and the total time spent decompressing is minimised. Saturation divers typically breathe a helium–oxygen mixture to prevent nitrogen narcosis, and limit work of breathing, but at shallow depths saturation diving has been done on nitrox mixtures.
Most of the physiological and medical aspects of diving to the same depths are much the same in saturation and bell-bounce ambient pressure diving, or are less of a problem, but there are medical and psychological effects of living under saturation for extended periods.
Saturation diving is a specialized form of diving; of the 3,300 commercial divers employed in the United States in 2015, 336 were saturation divers. Special training and certification is required, as the activity is inherently hazardous, and a set of standard operating procedures, emergency procedures, and a range of specialised equipment is used to control the risk, that require consistently correct performance by all the members of an extended diving team. The combination of relatively large skilled personnel requirements, complex engineering, and bulky, heavy equipment required to support a saturation diving project make it an expensive diving mode, but it allows direct human intervention at places that would not otherwise be practical, and where it is applied, it is generally more economically viable than other options, if such exist. (Full article...)
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Surface-supplied diving is a mode of underwater diving using equipment supplied with breathing gas through a diver's umbilical from the surface, either from the shore or from a diving support vessel, sometimes indirectly via a diving bell. This is different from scuba diving, where the diver's breathing equipment is completely self-contained and there is no essential link to the surface. The primary advantages of conventional surface supplied diving are lower risk of drowning and considerably larger breathing gas supply than scuba, allowing longer working periods and safer decompression. Disadvantages are the absolute limitation on diver mobility imposed by the length of the umbilical, encumbrance by the umbilical, and high logistical and equipment costs compared with scuba. The disadvantages restrict use of this mode of diving to applications where the diver operates within a small area, which is common in commercial diving work.
Airline, or hookah diving, and "compressor diving" are lower technology variants also using a breathing air supply from the surface. (Full article...)
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Rebreather diving is underwater diving using diving rebreathers, a class of underwater breathing apparatus which recirculate the breathing gas exhaled by the diver after replacing the oxygen used and removing the carbon dioxide metabolic product. Rebreather diving is practiced by recreational, military and scientific divers in applications where it has advantages over open circuit scuba, and surface supply of breathing gas is impracticable. The main advantages of rebreather diving are extended gas endurance, low noise levels, and lack of bubbles.
Rebreathers are generally used for scuba applications, but are also occasionally used for bailout systems for surface-supplied diving. Gas reclaim systems used for deep heliox diving use similar technology to rebreathers, as do saturation divinglife-support systems, but in these applications the gas recycling equipment is not carried by the diver. Atmospheric diving suits also carry rebreather technology to recycle breathing gas as part of the life-support system, but this article covers the procedures of ambient pressure diving using rebreathers carried by the diver.
Rebreathers are generally more complex to use than open circuit scuba, and have more potential points of failure, so acceptably safe use requires a greater level of skill, attention and situational awareness, which is usually derived from understanding the systems, diligent maintenance and overlearning the practical skills of operation and fault recovery. Fault tolerant design can make a rebreather less likely to fail in a way that immediately endangers the user, and reduces the task loading on the diver which in turn may lower the risk of operator error. (Full article...)
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Underwater diving, as a human activity, is the practice of descending below the water's surface to interact with the environment. It is also often referred to as diving, an ambiguous term with several possible meanings, depending on context. Immersion in water and exposure to high ambient pressure have physiological effects that limit the depths and duration possible in ambient pressure diving. Humans are not physiologically and anatomically well-adapted to the environmental conditions of diving, and various equipment has been developed to extend the depth and duration of human dives, and allow different types of work to be done.
In ambient pressure diving, the diver is directly exposed to the pressure of the surrounding water. The ambient pressure diver may dive on breath-hold (freediving) or use breathing apparatus for scuba diving or surface-supplied diving, and the saturation diving technique reduces the risk of decompression sickness (DCS) after long-duration deep dives. Atmospheric diving suits (ADS) may be used to isolate the diver from high ambient pressure. Crewed submersibles can extend depth range to full ocean depth, and remotely controlled or robotic machines can reduce risk to humans.
The environment exposes the diver to a wide range of hazards, and though the risks are largely controlled by appropriate diving skills, training, types of equipment and breathing gases used depending on the mode, depth and purpose of diving, it remains a relatively dangerous activity. Professional diving is usually regulated by occupational health and safety legislation, while recreational diving may be entirely unregulated. Diving activities are restricted to maximum depths of about 40 metres (130 ft) for recreational scuba diving, 530 metres (1,740 ft) for commercial saturation diving, and 610 metres (2,000 ft) wearing atmospheric suits. Diving is also restricted to conditions which are not excessively hazardous, though the level of risk acceptable can vary, and fatal incidents may occur.
Recreational diving (sometimes called sport diving or subaquatics) is a popular leisure activity. Technical diving is a form of recreational diving under more challenging conditions. Professional diving (commercial diving, diving for research purposes, or for financial gain) involves working underwater. Public safety diving is the underwater work done by law enforcement, fire rescue, and underwater search and recovery dive teams. Military diving includes combat diving, clearance diving and ships husbandry. Deep sea diving is underwater diving, usually with surface-supplied equipment, and often refers to the use of standard diving dress with the traditional copper helmet. Hard hat diving is any form of diving with a helmet, including the standard copper helmet, and other forms of free-flow and lightweight demand helmets. The history of breath-hold diving goes back at least to classical times, and there is evidence of prehistoric hunting and gathering of seafoods that may have involved underwater swimming. Technical advances allowing the provision of breathing gas to a diver underwater at ambient pressure are recent, and self-contained breathing systems developed at an accelerated rate following the Second World War. (Full article...)
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Scuba diving is a mode of underwater diving whereby divers use breathing equipment that is completely independent of a surface breathing gas supply, and therefore has a limited but variable endurance. The name scuba is an anacronym for "Self-Contained Underwater Breathing Apparatus" and was coined by Christian J. Lambertsen in a patent submitted in 1952. Scuba divers carry their own source of breathing gas, usually compressed air, affording them greater independence and movement than surface-supplied divers, and more time underwater than free divers. Although the use of compressed air is common, a gas blend with a higher oxygen content, known as enriched air or nitrox, has become popular due to the reduced nitrogen intake during long or repetitive dives. Also, breathing gas diluted with helium may be used to reduce the effects of nitrogen narcosis during deeper dives.
Open-circuit scuba systems discharge the breathing gas into the environment as it is exhaled, and consist of one or more diving cylinders containing breathing gas at high pressure which is supplied to the diver at ambient pressure through a diving regulator. They may include additional cylinders for range extension, decompression gas or emergency breathing gas. Closed-circuit or semi-closed circuit rebreather scuba systems allow recycling of exhaled gases. The volume of gas used is reduced compared to that of open-circuit, so a smaller cylinder or cylinders may be used for an equivalent dive duration. Rebreathers extend the time spent underwater compared to open-circuit for the same metabolic gas consumption; they produce fewer bubbles and less noise than open-circuit scuba, which makes them attractive to covert military divers to avoid detection, scientific divers to avoid disturbing marine animals, and media divers to avoid bubble interference.
Scuba diving may be done recreationally or professionally in a number of applications, including scientific, military and public safety roles, but most commercial diving uses surface-supplied diving equipment when this is practicable. Scuba divers engaged in armed forces covert operations may be referred to as frogmen, combat divers or attack swimmers.
Surface-supplied diving is a mode of underwater diving using equipment supplied with breathing gas through a diver's umbilical from the surface, either from the shore or from a diving support vessel, sometimes indirectly via a diving bell. This is different from scuba diving, where the diver's breathing equipment is completely self-contained and there is no essential link to the surface. The primary advantages of conventional surface supplied diving are lower risk of drowning and considerably larger breathing gas supply than scuba, allowing longer working periods and safer decompression. Disadvantages are the absolute limitation on diver mobility imposed by the length of the umbilical, encumbrance by the umbilical, and high logistical and equipment costs compared with scuba. The disadvantages restrict use of this mode of diving to applications where the diver operates within a small area, which is common in commercial diving work.