1.
Surface water
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Surface water is water on the surface of the planet such as in a river, lake, wetland, or ocean. It can be contrasted with groundwater and atmospheric water, non-saline surface water is replenished by precipitation and by recruitment from ground-water. Surface and groundwater are two entities, so they must be regarded as such. However, there is an ever-increasing need for management of the two as they are part of a system that is paramount when the demand for water exceeds the available supply. Depletion of surface and ground water sources for public consumption is caused by over-pumping, aquifers near river systems that are over-pumped have been known to deplete surface water sources as well. Research supporting this has found in numerous water budgets for a multitude of cities. Response times for an aquifer are long, however, a total ban on ground water usage during water recessions would allow surface water to retain better levels required for sustainable aquatic life. By reducing ground water pumping, the water supplies will be able to maintain their levels, as they recharge from direct precipitation, surface runoff. Environmental persistent pharmaceutical pollutant Meltwater Optimum water content for tillage Applied Hydrogeology, Fourth Edition by C. W. Fetter
2.
Alapaha River
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The Alapaha River /əˈlæpəhɑː/ is a 202-mile-long river in southern Georgia and northern Florida in the United States. It is a tributary of the Suwannee River, which flows to the Gulf of Mexico, the Hernando de Soto expedition narrative records mention a Yupaha village they encountered after they left Apalachee, the sound of which is suggestive of the Alapaha, a tributary of the Suwanee. Another reference to a village of Atapaha so closely resembles Alapaha that it is reasonable to suppose they are the same, augustine, Florida, probably on the Alapaha River. In the 1840s a German travel writer, Friedrich Gerstäcker wrote a novel called Alapaha, or the Renegades of the Border. A translation of this novel was published in the 1870s as #67 in a series of American narratives published by Beadle. During the American Civil War, the swamps along the Alapaha River in Berrien, Irwin, along its course it passes the Georgia towns of Rebecca, Alapaha, Willacoochee, Lakeland, and Statenville. Near Willacoochee, Georgia, the Alapaha collects the Willacoochee River, in Florida, it collects the Alapahoochee River and the short Little Alapaha River, which rises in Echols County, Georgia, and flows southwestward. The Alapaha River is an intermittent river for part of its course, during periods of low volume, the river disappears underground and becomes a subterranean river. At approximately 2.3 miles downstream from Jennings, Florida is a river sinkhole variously known as the Alapaha River Sink, Suck Hole and it is located at 30. 5855009°N83. 0528016°W /30.5855009, -83.0528016. A short distance away from the Devils Dens, the Dead River enters into the Alapaha River and it is a usually dry river bed with a number of sinkholes, including the Dead River Sink. A few more miles downstream is a sinkhole known as the Dead River Sink or the Siphon. At the latter point during the periods of low water flow, the Alapaha River later reappears at the Alapaha River Rise, which is about a half mile upstream from the confluence of the Alapaha River and the Suwanee River. During a period of low rainfall over 11 miles of the riverbed can be dry as the river goes underground, the United States Board on Geographic Names settled on Alapaha River as the streams name in 1891. According to the Geographic Names Information System, it has also known as
3.
Jennings, Florida
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Jennings is a town in Hamilton County, Florida, United States. The population was 833 at the 2000 census, as of 2004, the population recorded by the U. S. Census Bureau was 843. Jennings is located at 30°36′11″N 83°6′8″W, according to the United States Census Bureau, the town has a total area of 1.8 square miles, all land. As of the census of 2000, there were 833 people,282 households, the population density was 461.3 people per square mile. There were 321 housing units at a density of 177.8 per square mile. The racial makeup of the town was 43. 70% White,43. 10% African American,0. 60% Native American,0. 60% Asian,10. 08% from other races, hispanic or Latino of any race were 22. 69% of the population. 23. 0% of all households were made up of individuals and 11. 7% had someone living alone who was 65 years of age or older, the average household size was 2.89 and the average family size was 3.34. In the town, the population was out with 30. 6% under the age of 18,9. 0% from 18 to 24,25. 7% from 25 to 44,22. 4% from 45 to 64. The median age was 32 years, for every 100 females there were 98.8 males. For every 100 females age 18 and over, there were 99.3 males, the median income for a household in the town was $25,714, and the median income for a family was $25,938. Males had an income of $25,577 versus $15,982 for females. The per capita income for the town was $12,195, about 23. 8% of families and 30. 8% of the population were below the poverty line, including 42. 9% of those under age 18 and 20. 0% of those age 65 or over. North Hamilton Elementary will be consolidated into a new school, Hamilton County Elementary School. Its opening is scheduled for August 2017, the Suwannee River Regional Library System operates the Jennings Public Library
4.
Florida
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Florida /ˈflɒrᵻdə/ is a state located in the southeastern region of the United States. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia, to the east by the Atlantic Ocean, Florida is the 22nd-most extensive, the 3rd-most populous, and the 8th-most densely populated of the U. S. states. Jacksonville is the most populous municipality in the state and is the largest city by area in the contiguous United States, the Miami metropolitan area is Floridas most populous urban area. The city of Tallahassee is the state capital, much of the state is at or near sea level and is characterized by sedimentary soil. The climate varies from subtropical in the north to tropical in the south, the American alligator, American crocodile, Florida panther, and manatee can be found in the Everglades National Park. It was a location of the Seminole Wars against the Native Americans. Today, Florida is distinctive for its large Cuban expatriate community and high population growth, the states economy relies mainly on tourism, agriculture, and transportation, which developed in the late 19th century. Florida is also renowned for amusement parks, orange crops, the Kennedy Space Center, Florida has attracted many writers such as Marjorie Kinnan Rawlings, Ernest Hemingway and Tennessee Williams, and continues to attract celebrities and athletes. It is internationally known for golf, tennis, auto racing, by the 16th century, the earliest time for which there is a historical record, major Native American groups included the Apalachee, the Timucua, the Ais, the Tocobaga, the Calusa and the Tequesta. Florida was the first part of the continental United States to be visited and settled by Europeans, the earliest known European explorers came with the Spanish conquistador Juan Ponce de León. Ponce de León spotted and landed on the peninsula on April 2,1513 and he named the region La Florida. The story that he was searching for the Fountain of Youth is a myth, in May 1539, Conquistador Hernando de Soto skirted the coast of Florida, searching for a deep harbor to land. He described seeing a wall of red mangroves spread mile after mile, some reaching as high as 70 feet. Very soon, many smokes appeared along the whole coast, billowing against the sky, the Spanish introduced Christianity, cattle, horses, sheep, the Spanish language, and more to Florida. Both the Spanish and French established settlements in Florida, with varying degrees of success, in 1559, Don Tristán de Luna y Arellano established a settlement at present-day Pensacola, making it the first attempted settlement in Florida, but it was abandoned by 1561. Spain maintained tenuous control over the region by converting the tribes to Christianity. The area of Spanish Florida diminished with the establishment of English settlements to the north, the English attacked St. Augustine, burning the city and its cathedral to the ground several times. Florida attracted numerous Africans and African-Americans from adjacent British colonies who sought freedom from slavery, in 1738, Governor Manuel de Montiano established Fort Gracia Real de Santa Teresa de Mose near St
5.
Sinkhole
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A sinkhole, also known as a cenote, sink, sink-hole, shakehole, swallet, swallow hole, or doline, is a depression or hole in the ground caused by some form of collapse of the surface layer. Most are caused by karst processes—for example, the dissolution of carbonate rocks or suffosion processes. Sinkholes vary in size from 1 to 600 m both in diameter and depth, and vary in form from soil-lined bowls to bedrock-edged chasms, sinkholes may form gradually or suddenly, and are found worldwide. Sinkholes may capture surface drainage from running or standing water, but may form in high. Sinkholes that capture drainage can hold it in limestone caves. These caves may drain into tributaries of larger rivers, the formation of sinkholes involves natural processes of erosion or gradual removal of slightly soluble bedrock by percolating water, the collapse of a cave roof, or a lowering of the water table. Sinkholes often form through the process of suffosion, for example, groundwater may dissolve the carbonate cement holding the sandstone particles together and then carry away the lax particles, gradually forming a void. Occasionally a sinkhole may exhibit a visible opening into a cave below, sinkholes also occur in sandstone and quartzite terrains. As the rock dissolves, spaces and caverns develop underground and these sinkholes can be dramatic, because the surface land usually stays intact until there is not enough support. Then, a collapse of the land surface can occur. Sinkholes also form from human activity, such as the collapse of abandoned mines and salt cavern storage in salt domes in places like Louisiana, Mississippi, more commonly, sinkholes occur in urban areas due to water main breaks or sewer collapses when old pipes give way. They can also occur from the overpumping and extraction of groundwater, sinkholes can also form when natural water-drainage patterns are changed and new water-diversion systems are developed. Sinkholes tend to occur in karst landscapes, karst landscapes can have up to thousands of sinkholes within a small area, giving the landscape a pock-marked appearance. These sinkholes drain all the water, so there are only subterranean rivers in these areas, examples of karst landscapes with a plethora of massive sinkholes include Khammouan Mountains and Mamo Plateau. The largest known sinkholes formed in sandstone are Sima Humboldt and Sima Martel in Venezuela, some sinkholes form in thick layers of homogenous limestone. On the contact of limestone and insoluble rock below it, powerful underground rivers may form, in such conditions, the largest known sinkholes of the world have formed, like the 662-metre deep Xiaozhai Tiankeng, giant sótanos in Querétaro and San Luis Potosí states in Mexico and others. The state of Florida in the United States is known for having frequent sinkhole collapses, the Murge area in southern Italy also has numerous sinkholes. Sinkholes can be formed in retention ponds from large amounts of rain, an analysis of a case of sinkhole formation under a retention pond due to a large amount of rain can be seen in a sinkhole collapse study
6.
Floridan aquifer
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It underlies the entire state of Florida and parts of Alabama, Georgia, Mississippi, and South Carolina. The Floridan aquifer system is one of the worlds most productive aquifers, according to the U. S. Geological Survey, total withdrawals from the Floridan aquifer system in 2000 were ranked 5th highest of all principle aquifers in the Nation at 3,640 million gallons per day. Of the total, 49% was used for irrigation, 33% was used for water supply, 14% was used for industrial purposes. In 1936, geologist Victor Timothy Stringfield first identified the existence of the Floridan Aquifer in peninsular Florida and referred to the carbonate units as the principal artesian formations. In 1944, M. A. Warren of the Georgia Geological Survey described an extension of system in south Georgia. In 1953 and 1966 Stringfield also applied the term principal artesian aquifer to these rocks, with additional information collection, more zones of high and low hydraulic conductivity have been identified. As a result, the name Floridan Aquifer has evolved into Floridan aquifer system, withdrawals from the Floridan aquifer system began in 1887 when the City of Savannah, Georgia, began to supplement surface water withdrawals from the Savannah River with groundwater. Over time, the number of wells increased, as did the finished depths, industrial supply for pulp and paper mills became a large proportion of the water withdrawn starting in the late 1930s. In the 1950s, all municipal, domestic, and industrial supply and about half of agricultural supply in Orlando, groundwater withdrawals from the Floridan aquifer system increased steadily from 630 Mgal/d in 1950 to 3,430 Mgal/d in 1990. Much of the increase was due to increased agricultural demand, the Upper Floridan aquifer contains freshwater over much of its extent, though is brackish and saline south of Lake Okeechobee. The Floridan aquifer system crops out in central and southern Georgia where the limestone, the aquifer system generally dips below land surface to the south where it becomes buried beneath surficial sand deposits and clay. In areas depicted in brown in the image at the right and these regions particularly prone to sinkhole activity due to the proximity of the karstified limestone aquifer to land surface. Some of the fractures/conduits within the aquifer are large enough for divers to swim through. In west-central Florida, north Florida, and along the margin of the system, the limestone crops out. Where low-permeability clays of the upper confining unit are present and substantial, low permeability limestone rocks of Paleocene age form the base of the Floridan aquifer system. The Floridan aquifer system ranges in thickness from less than 100 feet in areas where the rocks pinch out to more than 3,700 feet in southwestern Florida. Where the Floridan aquifer system is at or near surface, clays are thin or absent and dissolution of the limestone is intensified and many springs. Transmissivity of the aquifer in karstified areas such as these is much higher owing to the development of large, Springs form where the water pressure is great enough for the groundwater to flow out on the land surface
7.
Water
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Water is a transparent and nearly colorless chemical substance that is the main constituent of Earths streams, lakes, and oceans, and the fluids of most living organisms. Its chemical formula is H2O, meaning that its molecule contains one oxygen, Water strictly refers to the liquid state of that substance, that prevails at standard ambient temperature and pressure, but it often refers also to its solid state or its gaseous state. It also occurs in nature as snow, glaciers, ice packs and icebergs, clouds, fog, dew, aquifers, Water covers 71% of the Earths surface. It is vital for all forms of life. Only 2. 5% of this water is freshwater, and 98. 8% of that water is in ice and groundwater. Less than 0. 3% of all freshwater is in rivers, lakes, and the atmosphere, a greater quantity of water is found in the earths interior. Water on Earth moves continually through the cycle of evaporation and transpiration, condensation, precipitation. Evaporation and transpiration contribute to the precipitation over land, large amounts of water are also chemically combined or adsorbed in hydrated minerals. Safe drinking water is essential to humans and other even though it provides no calories or organic nutrients. There is a correlation between access to safe water and gross domestic product per capita. However, some observers have estimated that by 2025 more than half of the population will be facing water-based vulnerability. A report, issued in November 2009, suggests that by 2030, in developing regions of the world. Water plays an important role in the world economy, approximately 70% of the freshwater used by humans goes to agriculture. Fishing in salt and fresh water bodies is a source of food for many parts of the world. Much of long-distance trade of commodities and manufactured products is transported by boats through seas, rivers, lakes, large quantities of water, ice, and steam are used for cooling and heating, in industry and homes. Water is an excellent solvent for a variety of chemical substances, as such it is widely used in industrial processes. Water is also central to many sports and other forms of entertainment, such as swimming, pleasure boating, boat racing, surfing, sport fishing, Water is a liquid at the temperatures and pressures that are most adequate for life. Specifically, at atmospheric pressure of 1 bar, water is a liquid between the temperatures of 273.15 K and 373.15 K
8.
Earth
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Earth, otherwise known as the World, or the Globe, is the third planet from the Sun and the only object in the Universe known to harbor life. It is the densest planet in the Solar System and the largest of the four terrestrial planets, according to radiometric dating and other sources of evidence, Earth formed about 4.54 billion years ago. Earths gravity interacts with objects in space, especially the Sun. During one orbit around the Sun, Earth rotates about its axis over 365 times, thus, Earths axis of rotation is tilted, producing seasonal variations on the planets surface. The gravitational interaction between the Earth and Moon causes ocean tides, stabilizes the Earths orientation on its axis, Earths lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years. About 71% of Earths surface is covered with water, mostly by its oceans, the remaining 29% is land consisting of continents and islands that together have many lakes, rivers and other sources of water that contribute to the hydrosphere. The majority of Earths polar regions are covered in ice, including the Antarctic ice sheet, Earths interior remains active with a solid iron inner core, a liquid outer core that generates the Earths magnetic field, and a convecting mantle that drives plate tectonics. Within the first billion years of Earths history, life appeared in the oceans and began to affect the Earths atmosphere and surface, some geological evidence indicates that life may have arisen as much as 4.1 billion years ago. Since then, the combination of Earths distance from the Sun, physical properties, in the history of the Earth, biodiversity has gone through long periods of expansion, occasionally punctuated by mass extinction events. Over 99% of all species that lived on Earth are extinct. Estimates of the number of species on Earth today vary widely, over 7.4 billion humans live on Earth and depend on its biosphere and minerals for their survival. Humans have developed diverse societies and cultures, politically, the world has about 200 sovereign states, the modern English word Earth developed from a wide variety of Middle English forms, which derived from an Old English noun most often spelled eorðe. It has cognates in every Germanic language, and their proto-Germanic root has been reconstructed as *erþō, originally, earth was written in lowercase, and from early Middle English, its definite sense as the globe was expressed as the earth. By early Modern English, many nouns were capitalized, and the became the Earth. More recently, the name is simply given as Earth. House styles now vary, Oxford spelling recognizes the lowercase form as the most common, another convention capitalizes Earth when appearing as a name but writes it in lowercase when preceded by the. It almost always appears in lowercase in colloquial expressions such as what on earth are you doing, the oldest material found in the Solar System is dated to 4. 5672±0.0006 billion years ago. By 4. 54±0.04 Gya the primordial Earth had formed, the formation and evolution of Solar System bodies occurred along with the Sun
9.
Fracture
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A fracture is the separation of an object or material into two or more pieces under the action of stress. The fracture of a solid usually occurs due to the development of certain displacement discontinuity surfaces within the solid, fracture strength or breaking strength is the stress when a specimen fails or fractures. The word fracture is often applied to bones of living creatures, or to crystalline materials, sometimes, individual crystals fracture without the structure actually separating into two or more pieces. Depending on the substance, a fracture reduces strength or inhibits transmission of waves, a detailed understanding of how fracture occurs in materials may be assisted by the study of fracture mechanics. Fracture strength, also known as breaking strength, is the stress at which a specimen fails via fracture and this is usually determined for a given specimen by a tensile test, which charts the stress-strain curve. The final recorded point is the fracture strength, ductile materials have a fracture strength lower than the ultimate tensile strength, whereas in brittle materials the fracture strength is equivalent to the UTS. If a ductile material reaches its ultimate strength in a load-controlled situation, it will continue to deform, with no additional load application. However, if the loading is displacement-controlled, the deformation of the material may relieve the load, in brittle fracture, no apparent plastic deformation takes place before fracture. In brittle crystalline materials, fracture can occur by cleavage as the result of tensile stress acting normal to crystallographic planes with low bonding. In amorphous solids, by contrast, the lack of a crystalline structure results in a conchoidal fracture, the sinking of RMS Titanic in 1912 from an iceberg collision is widely reported to have been due to brittle fracture of the hulls steel plates. Putting these two together, we get σ f r a c t u r e = E γ ρ4 a r o. Looking closely, we can see that sharp cracks and large defects both lower the strength of the material. Recently, scientists have discovered supersonic fracture, the phenomenon of crack propagation faster than the speed of sound in a material and this phenomenon was recently also verified by experiment of fracture in rubber-like materials. Brittle fracture may be avoided by limiting pressure and temperature within limits, each system has a brittle fracture prevention limit curve defined by the weakest components at given temperatures and pressures allowing for the largest undetected preexisting flaw in each component. In ductile fracture, extensive plastic deformation takes place before fracture, the terms rupture or ductile rupture describe the ultimate failure of ductile materials loaded in tension. Rather than cracking, the material pulls apart, generally leaving a rough surface, in this case there is slow propagation and an absorption of a large amount energy before fracture. The ductility of a material is referred to as toughness. Many ductile metals, especially materials with high purity, can sustain very large deformation of 50–100% or more strain before fracture under favorable loading condition, the strain at which the fracture happens is controlled by the purity of the materials
10.
Stratum
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In geology and related fields, a stratum is a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers. The stratum is the unit in a stratigraphic column and forms the basis of the study of stratigraphy. Each layer is one of a number of parallel layers that lie one upon another. They may extend over hundreds of thousands of kilometers of the Earths surface. Strata are typically seen as bands of different colored or differently structured material exposed in cliffs, road cuts, quarries, individual bands may vary in thickness from a few millimeters to a kilometer or more. Each band represents a mode of deposition, river silt, beach sand, coal swamp, sand dune, lava bed. Geologists study rock strata and categorize them by the material of beds, each distinct layer is typically assigned to the name of sheet, usually based on a town, river, mountain, or region where the formation is exposed and available for study. For example, the Burgess Shale is an exposure of dark, occasionally fossiliferous. Slight distinctions in material in a formation may be described as members, formations are collected into groups while groups may be collected into supergroups. Archaeological horizon Geologic formation Geologic map Geologic unit Law of superposition Bed GeoWhen Database
11.
Aquifer
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An aquifer is an underground layer of water-bearing permeable rock, rock fractures or unconsolidated materials from which groundwater can be extracted using a water well. The study of flow in aquifers and the characterization of aquifers is called hydrogeology. Related terms include aquitard, which is a bed of low permeability along an aquifer, and aquiclude, if the impermeable area overlies the aquifer, pressure could cause it to become a confined aquifer. Aquifers may occur at various depths and those closer to the surface are not only more likely to be used for water supply and irrigation, but are also more likely to be topped up by the local rainfall. Many desert areas have limestone hills or mountains within them or close to them that can be exploited as groundwater resources, overexploitation can lead to the exceeding of the practical sustained yield, i. e. more water is taken out than can be replenished. The beach provides a model to help visualize an aquifer, if a hole is dug into the sand, very wet or saturated sand will be located at a shallow depth. This hole is a well, the wet sand represents an aquifer. In 2013 large freshwater aquifers were discovered under continental shelves off Australia, China, North America and they contain an estimated half a million cubic kilometers of “low salinity” water that could be economically processed into potable water. The reserves formed when ocean levels were lower and rainwater made its way into the ground in areas that were not submerged until the ice age ended 20,000 years ago. The volume is estimated to be 100x the amount of extracted from other aquifers since 1900. The above diagram indicates typical flow directions in a view of a simple confined or unconfined aquifer system. The system shows two aquifers with one aquitard between them, surrounded by the bedrock aquiclude, which is in contact with a gaining stream, the water table and unsaturated zone are also illustrated. An aquitard is a zone within the earth that restricts the flow of groundwater from one aquifer to another, an aquitard can sometimes, if completely impermeable, be called an aquiclude or aquifuge. Aquitards are composed of layers of clay or non-porous rock with low hydraulic conductivity. Groundwater can be found at every point in the Earths shallow subsurface to some degree. Saturated means the head of the water is greater than atmospheric pressure. The definition of the table is the surface where the pressure head is equal to atmospheric pressure. Unsaturated conditions occur above the table where the pressure head is negative
12.
Soil
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Soil is a mixture of minerals, organic matter, gases, liquids, and countless organisms that together support life on Earth. Soil is called the Skin of the Earth and interfaces with the lithosphere, the hydrosphere, the atmosphere, the term pedolith, used commonly to refer to the soil, literally translates ground stone. Soil consists of a phase of minerals and organic matter, as well as a porous phase that holds gases. Accordingly, soils are often treated as a system of solids, liquids. Soil is a product of the influence of climate, relief, organisms, Soil continually undergoes development by way of numerous physical, chemical and biological processes, which include weathering with associated erosion. Given its complexity and strong internal connectedness soil has been considered as an ecosystem by soil ecologists. Most soils have a dry bulk density between 1.1 and 1.6 g/cm3, while the particle density is much higher. Little of the soil of planet Earth is older than the Pleistocene and none is older than the Cenozoic, Soil science has two basic branches of study, edaphology and pedology. Edaphology is concerned with the influence of soils on living things, pedology is focused on the formation, description, and classification of soils in their natural environment. In engineering terms, soil is referred to as regolith, or loose material that lies above the solid geology. Soil is commonly referred to as earth or dirt, technically, as soil resources serve as a basis for food security, the international community advocates its sustainable and responsible use through different types of soil governance. Soil is a component of the Earths ecosystem. The worlds ecosystems are impacted in far-reaching ways by the carried out in the soil, from ozone depletion and global warming, to rainforest destruction. Following the atmosphere, the soil is the next largest carbon reservoir on Earth, as the planet warms, soils will add carbon dioxide to the atmosphere due to its increased biological activity at higher temperatures. Thus, soil carbon losses likely have a positive feedback response to global warming. Since soil has a range of available niches and habitats. A gram of soil can contain billions of organisms, belonging to thousands of species, mostly microbial, Soil has a mean prokaryotic density of roughly 108 organisms per gram, whereas the ocean has no more than 107 procaryotic organisms per milliliter of seawater. Since plant roots need oxygen, ventilation is an important characteristic of soil and this ventilation can be accomplished via networks of interconnected soil pores, which also absorb and hold rainwater making it readily available for plant uptake
13.
Water table
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The water table is the upper surface of the zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with water, the water table is the surface where the water pressure head is equal to the atmospheric pressure. It may be visualized as the surface of the materials that are saturated with groundwater in a given vicinity. The groundwater may be from precipitation or from groundwater flowing into the aquifer, in areas with sufficient precipitation, water infiltrates through pore spaces in the soil, passing through the unsaturated zone. At increasing depths water fills in more of the spaces in the soils. Below the water table, in the zone, layers of permeable rock that yield groundwater are called aquifers. In less permeable soils, such as tight bedrock formations and historic lakebed deposits, the water table should not be confused with the water level in a deeper well. The elevation of the water in this well is dependent upon the pressure in the deeper aquifer and is referred to as the potentiometric surface. The water table may vary due to changes such as precipitation and evapotranspiration. Springs, rivers, lakes and oases occur when the table reaches the surface. Springs commonly form on hillsides, where the Earths slanting surface may intersect with the water table, Groundwater entering rivers and lakes accounts for the base-flow water levels in water bodies. Within an aquifer, the table is rarely horizontal, but reflects the surface relief due to the capillary effect in soils, sediments. In the aquifer, groundwater flows from points of pressure to points of lower pressure. The slope of the table is known as the hydraulic gradient, which depends on the rate at which water is added to and removed from the aquifer. This occurs when there is a layer of rock or sediment or relatively impermeable layer above the main water table/aquifer. If a perched aquifers flow intersects the Earths dry surface, at a wall for example. On low-lying oceanic islands with porous soil, freshwater tends to collect in lenticular pools on top of the denser seawater intruding from the sides of the islands, such an islands freshwater lens, and thus the water table, rises and falls with the tides. In some regions, for example, Great Britain or California, winter precipitation is higher than summer precipitation
14.
Groundwater recharge
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Groundwater recharge or deep drainage or deep percolation is a hydrologic process where water moves downward from surface water to groundwater. Recharge is the method through which water enters an aquifer. This process usually occurs in the zone below plant roots and is often expressed as a flux to the water table surface. Recharge occurs both naturally and through anthropogenic processes, where rainwater and or reclaimed water is routed to the subsurface, groundwater is recharged naturally by rain and snow melt and to a smaller extent by surface water. Recharge may be impeded somewhat by human activities including paving, development and these activities can result in loss of topsoil resulting in reduced water infiltration, enhanced surface runoff and reduction in recharge. Use of groundwaters, especially for irrigation, may lower the water tables. Recharge can help move excess salts that accumulate in the zone to deeper soil layers. Tree roots increase water saturation into groundwater reducing water runoff, flooding temporarily increases river bed permeability by moving clay soils downstream, and this increases aquifer recharge. Artificial groundwater recharge is becoming important in India, where over-pumping of groundwater by farmers has led to underground resources becoming depleted. Another environmental issue is the disposal of waste through the water such as dairy farms, industrial. Wetlands help maintain the level of the table and exert control on the hydraulic head. This provides force for groundwater recharge and discharge to other waters as well, the extent of groundwater recharge by a wetland is dependent upon soil, vegetation, site, perimeter to volume ratio, and water table gradient. Groundwater recharge occurs through mineral soils found primarily around the edges of wetlands The soil under most wetlands is relatively impermeable, a high perimeter to volume ratio, such as in small wetlands, means that the surface area through which water can infiltrate into the groundwater is high. Groundwater recharge is typical in small wetlands such as prairie potholes, researchers have discovered groundwater recharge of up to 20% of wetland volume per season. If water falls uniformly over a field such that capacity of the soil is not exceeded. If instead water puddles in low-lying areas, the water volume concentrated over a smaller area may exceed field capacity resulting in water that percolates down to recharge groundwater. The larger the relative contributing runoff area is, the more focused infiltration is, the recurring process of water that falls relatively uniformly over an area, flowing to groundwater selectively under surface depressions is depression focused recharge. Water tables rise under such depressions, depression focused groundwater recharge can be very important in arid regions
15.
Spring (hydrology)
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A spring is any natural situation where water flows from an aquifer to the Earths surface. It is a component of the hydrosphere, a spring may be the result of karst topography where surface water has infiltrated the Earths surface, becoming part of the area groundwater. The groundwater then travels through a network of cracks and fissure—openings ranging from intergranular spaces to large caves, the water eventually emerges from below the surface, in the form of a karst spring. The forcing of the spring to the surface can be the result of an aquifer in which the recharge area of the spring water table rests at a higher elevation than that of the outlet. Spring water forced to the surface by elevated sources are artesian wells and this is possible even if the outlet is in the form of a 300-foot-deep cave. In this case the cave is used like a hose by the higher elevated area of groundwater to exit through the lower elevation opening. Non-artesian springs may simply flow from a higher elevation through the earth to a lower elevation, still other springs are the result of pressure from an underground source in the earth, in the form of volcanic activity. The result can be water at elevated temperature such as a hot spring, the action of the groundwater continually dissolves permeable bedrock such as limestone and dolomite, creating vast cave systems. The term seep refers to springs with small flow rates in which the water has filtered through permeable earth. Fracture springs, discharge from faults, joints, or fissures in the earth, tubular springs, in which the water flows from underground caverns. Spring discharge, or resurgence, is determined by the springs recharge basin, factors that affect the recharge include the size of the area in which groundwater is captured, the amount of precipitation, the size of capture points, and the size of the spring outlet. Water may leak into the system from many sources including permeable earth, sinkholes. In some cases entire creeks seemingly disappear as the water sinks into the ground via the stream bed, grand Gulf State Park in Missouri is an example of an entire creek vanishing into the groundwater system. The water emerges 9 miles away, forming some of the discharge of Mammoth Spring in Arkansas, human activity may also affect a springs discharge--withdrawal of groundwater reduces the water pressure in an aquifer, decreasing the volume of flow. Springs are often classified by the volume of the water they discharge, the largest springs are called first-magnitude, defined as springs that discharge water at a rate of at least 2800 liters or 100 cubic feet of water per second. The scale for spring flow is as follows, Minerals become dissolved in the water as it moves through the underground rocks and this may give the water flavor and even carbon dioxide bubbles, depending on the nature of the geology through which it passes. This is why spring water is bottled and sold as mineral water. Springs that contain significant amounts of minerals are sometimes called mineral springs, Springs that contain large amounts of dissolved sodium salts, mostly sodium carbonate, are called soda springs
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Seep (hydrology)
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A seep is a moist or wet place where water, usually groundwater, reaches the earths surface from an underground aquifer. Seeps are usually not of sufficient volume to be flowing beyond their above-ground location and they are part of the limnology-geomorphology system. Like a higher volume spring, the water is only from underground sources, seeps mostly occur in lower elevation areas because water runs downhill, but can happen higher up if the groundwater present is abundant enough. Along with natural seeps, man made seeps can occur by digging anywhere where there is wet ground and this method can be useful for survival purposes and helps the local wildlife by adding another water source to the area. Seeps often form a puddle, and are important for wildlife, bird. When they support mud-puddling many butterfly species can obtain nutrients such as salts and amino acids, seep is often used in environmental sciences to define an exfiltration zone where contaminated water, e. g. from waste dumps, leaves a waste system area. Seeps are often important smaller wildlife water sources, and indicated by lower riparian vegetation, seeps can also contribute to streams. If a stream is flowing below a water table then the stream receives contributions from the water via seepage. This allows for a drainage of the water along with creating a more substantial stream to flow. The seep could be effective during a rain-less period of the area in which the seep can actually prolong the stream’s flow by adding water from the groundwater. Aquifer Mud-puddling Puddle Rill Riparian zone restoration Spring Soil mechanics, Permeability and seepage Meinzer, Oscar E. ed. Hydrology
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Oasis
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In geography, an oasis is an isolated area of vegetation in a desert, typically surrounding a spring or similar water source, such as a pond or small lake. Oases also provide habitat for animals and even if the area is big enough. The location of oases has been of importance for trade and transportation routes in desert areas, caravans must travel via oases so that supplies of water. Thus, political or military control of an oasis has in many cases meant control of trade on a particular route. For example, the oases of Awjila, Ghadames, and Kufra, oases are formed from underground rivers or aquifers such as an artesian aquifer, where water can reach the surface naturally by pressure or by man-made wells. Occasional brief thunderstorms provide subterranean water to sustain natural oases, such as the Tuat, substrata of impermeable rock and stone can trap water and retain it in pockets, or on long faulting subsurface ridges or volcanic dikes water can collect and percolate to the surface. Any incidence of water is used by migrating birds, which also pass seeds with their droppings which will grow at the waters edge forming an oasis. It can also be used to plant crops, the word oasis came into English via Latin, oasis from Ancient Greek, ὄασις óasis, which in turn is a direct borrowing from Demotic Egyptian. The word for oasis in the later attested Coptic language is wahe or ouahe which means a dwelling place, people who live in an oasis must manage land and water use carefully, fields must be irrigated to grow plants like apricots, dates, figs, and olives. The most important plant in an oasis is the date palm and these palm trees provide shade for smaller trees like peach trees, which form the middle layer. By growing plants in different layers, the farmers make best use of the soil, many vegetables are also grown and some cereals, such as barley, millet, and wheat, are grown where there is more moisture. Great Man-Made River – the worlds largest irrigation project, developed in Libya to connect cities with fossil water. Guelta Mirage Oasification Qanat Wadi Water supply référence, Jardins au désert |Battesti, Jardins au désert, Evolution des pratiques et savoirs oasiens, Jérid tunisien, Paris, Éditions IRD, coll. À travers champs,2005,440 p. ISBN 2-7099-1564-2 Open Archives, book in free access / in French The dictionary definition of oasis at Wiktionary
18.
Wetland
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A wetland is a land area that is saturated with water, either permanently or seasonally, such that it takes on the characteristics of a distinct ecosystem. The primary factor that distinguishes wetlands from other forms or water bodies is the characteristic vegetation of aquatic plants. Wetlands play a number of roles in the environment, principally water purification, flood control, carbon sink, Wetlands are also considered the most biologically diverse of all ecosystems, serving as home to a wide range of plant and animal life. Wetlands occur naturally on every continent except Antarctica, the largest including the Amazon River basin, the West Siberian Plain, the water found in wetlands can be freshwater, brackish, or saltwater. The main wetland types include swamps, marshes, bogs, and fens, and sub-types include mangrove, carr, pocosin, the UN Millennium Ecosystem Assessment determined that environmental degradation is more prominent within wetland systems than any other ecosystem on Earth. International conservation efforts are being used in conjunction with the development of rapid assessment tools to people about wetland issues. Constructed wetlands can be used to treat municipal and industrial wastewater as well as stormwater runoff and they may also play a role in water-sensitive urban design. A patch of land that develops pools of water after a storm would not be considered a wetland. Wetlands have unique characteristics, they are distinguished from other water bodies or landforms based on their water level. Specifically, wetlands are characterized as having a table that stands at or near the land surface for a long enough period each year to support aquatic plants. A more concise definition is a community composed of hydric soil, Wetlands have also been described as ecotones, providing a transition between dry land and water bodies. In environmental decision-making, there are subsets of definitions that are agreed upon to make regulatory and policy decisions. A wetland is an ecosystem that arises when inundation by water produces soils dominated by anaerobic processes, There are four main kinds of wetlands – marsh, swamp, bog and fen. Some experts also recognize wet meadows and aquatic ecosystems as additional wetland types, the largest wetlands in the world include the swamp forests of the Amazon and the peatlands of Siberia. Under the Ramsar international wetland conservation treaty, wetlands are defined as follows, Article 2.1, may incorporate riparian and coastal zones adjacent to the wetlands, and islands or bodies of marine water deeper than six metres at low tide lying within the wetlands. Although the general definition given above applies around the world, each county, Wetlands generally include swamps, marshes, bogs and similar areas. This definition has been used in the enforcement of the Clean Water Act, some US states, such as Massachusetts and New York, have separate definitions that may differ from the federal governments. It is not uncommon for a wetland to be dry for long portions of the growing season, the most important factor producing wetlands is flooding
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Agriculture
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Agriculture is the cultivation and breeding of animals, plants and fungi for food, fiber, biofuel, medicinal plants and other products used to sustain and enhance human life. Agriculture was the key development in the rise of human civilization. The study of agriculture is known as agricultural science, the history of agriculture dates back thousands of years, and its development has been driven and defined by greatly different climates, cultures, and technologies. Industrial agriculture based on large-scale monoculture farming has become the dominant agricultural methodology, genetically modified organisms are an increasing component of agriculture, although they are banned in several countries. Agricultural food production and water management are increasingly becoming global issues that are fostering debate on a number of fronts, the major agricultural products can be broadly grouped into foods, fibers, fuels, and raw materials. Specific foods include cereals, vegetables, fruits, oils, meats, fibers include cotton, wool, hemp, silk and flax. Raw materials include lumber and bamboo, other useful materials are also produced by plants, such as resins, dyes, drugs, perfumes, biofuels and ornamental products such as cut flowers and nursery plants. The word agriculture is a late Middle English adaptation of Latin agricultūra, from ager, field, Agriculture usually refers to human activities, although it is also observed in certain species of ant, termite and ambrosia beetle. To practice agriculture means to use resources to produce commodities which maintain life, including food, fiber, forest products, horticultural crops. This definition includes arable farming or agronomy, and horticulture, all terms for the growing of plants, even then, it is acknowledged that there is a large amount of knowledge transfer and overlap between silviculture and agriculture. In traditional farming, the two are often combined even on small landholdings, leading to the term agroforestry, Agriculture began independently in different parts of the globe, and included a diverse range of taxa. At least 11 separate regions of the Old and New World were involved as independent centers of origin, wild grains were collected and eaten from at least 105,000 years ago. Pigs were domesticated in Mesopotamia around 15,000 years ago, rice was domesticated in China between 13,500 and 8,200 years ago, followed by mung, soy and azuki beans. Sheep were domesticated in Mesopotamia between 13,000 and 11,000 years ago. From around 11,500 years ago, the eight Neolithic founder crops, emmer and einkorn wheat, hulled barley, peas, lentils, bitter vetch, chick peas and flax were cultivated in the Levant. Cattle were domesticated from the aurochs in the areas of modern Turkey. In the Andes of South America, the potato was domesticated between 10,000 and 7,000 years ago, along with beans, coca, llamas, alpacas, sugarcane and some root vegetables were domesticated in New Guinea around 9,000 years ago. Sorghum was domesticated in the Sahel region of Africa by 7,000 years ago, cotton was domesticated in Peru by 5,600 years ago, and was independently domesticated in Eurasia at an unknown time
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City
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A city is a large and permanent human settlement. Cities generally have complex systems for sanitation, utilities, land usage, housing, a big city or metropolis usually has associated suburbs and exurbs. Such cities are associated with metropolitan areas and urban areas. Once a city expands far enough to another city, this region can be deemed a conurbation or megalopolis. Damascus is arguably the oldest city in the world, in terms of population, the largest city proper is Shanghai, while the fastest-growing is Dubai. There is not enough evidence to assert what conditions gave rise to the first cities, some theorists have speculated on what they consider suitable pre-conditions and basic mechanisms that might have been important driving forces. The conventional view holds that cities first formed after the Neolithic revolution, the Neolithic revolution brought agriculture, which made denser human populations possible, thereby supporting city development. The advent of farming encouraged hunter-gatherers to abandon nomadic lifestyles and to settle near others who lived by agricultural production, the increased population density encouraged by farming and the increased output of food per unit of land created conditions that seem more suitable for city-like activities. In his book, Cities and Economic Development, Paul Bairoch takes up position in his argument that agricultural activity appears necessary before true cities can form. According to Vere Gordon Childe, for a settlement to qualify as a city, it must have enough surplus of raw materials to support trade and a relatively large population. To illustrate this point, Bairoch offers an example, Western Europe during the pre-Neolithic, when the cost of transport is taken into account, the figure rises to 200,000 square kilometres. Bairoch noted that this is roughly the size of Great Britain, the urban theorist Jane Jacobs suggests that city formation preceded the birth of agriculture, but this view is not widely accepted. In his book City Economics, Brendan OFlaherty asserts Cities could persist—as they have for thousands of years—only if their advantages offset the disadvantages, OFlaherty illustrates two similar attracting advantages known as increasing returns to scale and economies of scale, which are concepts usually associated with businesses. Their applications are seen in more basic economic systems as well, increasing returns to scale occurs when doubling all inputs more than doubles the output an activity has economies of scale if doubling output less than doubles cost. To offer an example of these concepts, OFlaherty makes use of one of the oldest reasons why cities were built, in this example, the inputs are anything that would be used for protection and the output is the area protected and everything of value contained in it. OFlaherty then asks that we suppose the protected area is square, the advantage is expressed as, O = s 2, where O is the output and s stands for the length of a side. This equation shows that output is proportional to the square of the length of a side, the inputs depend on the length of the perimeter, I =4 s, where I stands for the quantity of inputs. So there are increasing returns to scale, O = I2 /16 and this equation shows that with twice the inputs, you produce quadruple the output
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Industry
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Industry is the production of goods or related services within an economy. The major source of revenue of a group or company is the indicator of its relevant industry, when a large group has multiple sources of revenue generation, it is considered to be working in different industries. Manufacturing industry became a key sector of production and labour in European and North American countries during the Industrial Revolution, upsetting previous mercantile and this came through many successive rapid advances in technology, such as the production of steel and coal. Following the Industrial Revolution, possibly a third of the economic output are derived that is from manufacturing industries. Many developed countries and many developing/semi-developed countries depend significantly on manufacturing industry, Industries, the countries they reside in, and the economies of those countries are interlinked in a complex web of interdependence. Industries can be classified in a variety of ways, at the top level, industry is often classified according to the three-sector theory into sectors, primary, secondary, and tertiary. Some authors add quaternary or even quinary sectors, over time, the fraction of a societys industry within each sector changes. Below the economic sectors there are other more detailed industry classifications. These classification systems commonly divide industries according to functions and markets. Market-based classification systems such as the Global Industry Classification Standard and the Industry Classification Benchmark are used in finance, the International Standard Industrial Classification of all economic activities is the most complete and systematic industrial classification made by the United Nations Statistics Division. ISIC is a classification of economic activities arranged so that entities can be classified according to the activity they carry out. The Industrial Revolution led to the development of factories for large-scale production, originally the factories were steam-powered, but later transitioned to electricity once an electrical grid was developed. The mechanized assembly line was introduced to parts in a repeatable fashion. This led to significant increases in efficiency, lowering the cost of the end process, later automation was increasingly used to replace human operators. This process has accelerated with the development of the computer and the robot, historically certain manufacturing industries have gone into a decline due to various economic factors, including the development of replacement technology or the loss of competitive advantage. An example of the former is the decline in manufacturing when the automobile was mass-produced. A recent trend has been the migration of prosperous, industrialized nations towards a post-industrial society and this is manifested by an increase in the service sector at the expense of manufacturing, and the development of an information-based economy, the so-called informational revolution. In a post-industrial society, manufacturing is relocated to more favourable locations through a process of off-shoring
22.
Water well
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A water well is an excavation or structure created in the ground by digging, driving, boring, or drilling to access groundwater in underground aquifers. The well water is drawn by a pump, or using containers, such as buckets, placing a lining in the well shaft helps create stability and linings of wood or wickerwork date back at least as far as the Iron Age. Wells have been sunk by hand digging as is the case in rural developing areas. These wells are inexpensive and low-tech as they use mostly manual labour, a more modern method called caissoning uses pre-cast reinforced concrete well rings that are lowered into the hole. Deeper wells can be excavated by hand drilling methods or machine drilling, using a bit in a borehole, drilled wells are usually cased with a factory-made pipe composed of steel or plastic. Drilled wells can access water at greater depths than dug wells. A collector well can be constructed adjacent to a lake or stream with water percolating through the intervening material. The site of a well can be selected by a hydrogeologist, Water may be pumped or hand drawn. Impurities from the surface can easily reach shallow sources and contamination of the supply by pathogens or chemical contaminants needs to be avoided, Well water typically contains more minerals in solution than surface water and may require treatment before being potable. Soil salination can occur as the water falls and the surrounding soil begins to dry out. Another environmental problem is the potential for methane to seep into the water, hand-dug wells are excavations with diameters large enough to accommodate one or more people with shovels digging down to below the water table. The excavation is braced horizontally to avoid landslide or erosion endangering the people digging, a more modern method called caissoning uses reinforced concrete or plain concrete pre-cast well rings that are lowered into the hole. A well-digging team digs under a ring and the well column slowly sinks into the aquifer. Hand-dug wells are inexpensive and low tech as they use mostly manual labour to access groundwater in rural locations in developing countries and they may be built with a high degree of community participation, or by local entrepreneurs who specialize in hand-dug wells. They have been excavated to 60 metres. They have low operational and maintenance costs, in part because water can be extracted by hand bailing, without a pump. The water is coming from an aquifer or groundwater, and can be easily deepened. The yield of existing hand dug wells may be improved by deepening or introducing vertical tunnels or perforated pipes, drawbacks to hand-dug wells are numerous
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Hydrogeology
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Hydrogeology is the area of geology that deals with the distribution and movement of groundwater in the soil and rocks of the Earths crust. The term geohydrology is often used interchangeably, some make the minor distinction between a hydrologist or engineer applying themselves to geology, and a geologist applying themselves to hydrology. Hydrogeology is a subject, it can be difficult to account fully for the chemical, physical, biological. The study of the interaction between groundwater movement and geology can be quite complex, Groundwater does not always follow the surface topography, groundwater follows pressure gradients, often through fractures and conduits in circuitous paths. Taking into account the interplay of the different facets of a multi-component system often requires knowledge in diverse fields at both the experimental and theoretical levels. The following is a more traditional introduction to the methods and nomenclature of saturated subsurface hydrology, hydrogeology, as stated above, is a branch of the earth sciences dealing with the flow of water through aquifers and other shallow porous media. The very shallow flow of water in the subsurface is pertinent to the fields of science, agriculture and civil engineering. The general flow of fluids in deeper formations is also a concern of geologists, geophysicists, Groundwater is a slow-moving, viscous fluid, many of the empirically derived laws of groundwater flow can be alternately derived in fluid mechanics from the special case of Stokes flow. The mathematical relationships used to describe the flow of water through porous media are the diffusion and Laplace equations, steady groundwater flow has been simulated using electrical, elastic and heat conduction analogies. Transient groundwater flow is analogous to the diffusion of heat in a solid, traditionally, the movement of groundwater has been studied separately from surface water, climatology, and even the chemical and microbiological aspects of hydrogeology. As the field of hydrogeology matures, the interactions between groundwater, surface water, water chemistry, soil moisture and even climate are becoming more clear. For example, aquifer drawdown or overdrafting and the pumping of water may be a contributing factor to sea-level rise. One of the tasks a hydrogeologist typically performs is the prediction of future behavior of an aquifer system, based on analysis of past. Some hypothetical, but characteristic questions asked would be, Can the aquifer support another subdivision, will the river dry up if the farmer doubles his irrigation. Did the chemicals from the dry cleaning facility travel through the aquifer to my well, will the plume of effluent leaving my neighbors septic system flow to my drinking water well. Most of these questions can be addressed through simulation of the hydrologic system, accurate simulation of the aquifer system requires knowledge of the aquifer properties and boundary conditions. Therefore, a task of the hydrogeologist is determining aquifer properties using aquifer tests. In order to further characterize aquifers and aquitards some primary and derived physical properties are introduced below, aquifers are broadly classified as being either confined or unconfined, and either saturated or unsaturated, the type of aquifer affects what properties control the flow of water in that medium
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Hydrology
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Hydrology is the scientific study of the movement, distribution, and quality of water on Earth and other planets, including the water cycle, water resources and environmental watershed sustainability. A practitioner of hydrology is a hydrologist, working within the fields of earth or environmental science, physical geography, geology or civil, Hydrology subdivides into surface water hydrology, groundwater hydrology, and marine hydrology. Domains of hydrology include hydrometeorology, surface hydrology, hydrogeology, drainage-basin management and water quality, oceanography and meteorology are not included because water is only one of many important aspects within those fields. Hydrological research can inform environmental engineering, policy and planning, the term hydrology comes from Greek, ὕδωρ, hýdōr, water, and λόγος, lógos, study. Chemical hydrology is the study of the characteristics of water. Ecohydrology is the study of interactions between organisms and the hydrologic cycle, hydrogeology is the study of the presence and movement of groundwater. Hydroinformatics is the adaptation of technology to hydrology and water resources applications. Hydrometeorology is the study of the transfer of water and energy between land and water surfaces and the lower atmosphere. Isotope hydrology is the study of the signatures of water. Surface hydrology is the study of processes that operate at or near Earths surface. Drainage basin management covers water-storage, in the form of reservoirs, water quality includes the chemistry of water in rivers and lakes, both of pollutants and natural solutes. Determining the water balance of a region, mitigating and predicting flood, landslide and drought risk. Real-time flood forecasting and flood warning, designing irrigation schemes and managing agricultural productivity. Part of the module in catastrophe modeling. Designing dams for water supply or hydroelectric power generation, designing sewers and urban drainage system. Analyzing the impacts of antecedent moisture on sanitary sewer systems, predicting geomorphologic changes, such as erosion or sedimentation. Assessing the impacts of natural and anthropogenic environmental change on water resources, assessing contaminant transport risk and establishing environmental policy guidelines. Hydrology has been a subject of investigation and engineering for millennia, for example, about 4000 BC the Nile was dammed to improve agricultural productivity of previously barren lands
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Permafrost
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In geology, permafrost is ground, including rock or soil, at or below the freezing point of water 0 °C for two or more years. Most permafrost is located in high latitudes, but alpine permafrost may exist at altitudes in much lower latitudes. Ground ice is not always present, as may be in the case of nonporous bedrock, Permafrost accounts for 0. 022% of total water on earth and exists in 24% of exposed land in the Northern Hemisphere. It also occurs subsea on the shelves of the continents surrounding the Arctic Ocean, portions of which were exposed during the last glacial period. A global temperature rise of 1.5 °C above current levels would be enough to start the thawing of permafrost in Siberia, Permafrost is soil, rock or sediment that is frozen for more than two consecutive years. In areas not overlain by ice, it exists beneath a layer of soil, rock or sediment, in practice, this means that permafrost occurs at an average air temperature of -2 °C or colder. Active layer thickness varies with the season, but is 0.3 to 4 meters thick, in the Northern Hemisphere, 24% of the ice-free land area, equivalent to 19 million square kilometers, is more or less influenced by permafrost. Most of this area is found in Siberia, northern Canada, Alaska, beneath the active layer annual temperature swings of permafrost become smaller with depth. The deepest depth of permafrost occurs where geothermal heat maintains a temperature above freezing, above that bottom limit there may be permafrost, whose temperature doesnt change annually—isothermal permafrost. The extent of permafrost varies with the climate, today, a considerable area of the Arctic is covered by permafrost. Overlying permafrost is an active layer that seasonally thaws during the summer. Plant life can be supported only within the active layer since growth can occur only in soil that is fully thawed for some part of the year, thickness of the active layer varies by year and location, but is typically 0. 6–4 m thick. In areas of continuous permafrost and harsh winters, the depth of the permafrost can exceed 1,400 m, Permafrost can also store carbon, both as peat and as methane. Work investigating the permafrost carbon pool size estimates that 1400–1700 Gt of carbon is stored in the northern circumpolar permafrost region, while a recent study that includes stores of the Tibetan Plateau, estimates total carbon pools in the permafrost of the Northern Hemisphere to be 1832 Gt. This large carbon pool represents more carbon than currently exists in all living things, Permafrost typically forms in any climate where the mean annual air temperature is less than the freezing point of water. Exceptions are found in moist-wintered forest climates, such as in Northern Scandinavia and the North-Eastern part of European Russia west of the Urals, fossil cold anomalies in the Geothermal gradient in areas where deep permafrost developed during the Pleistocene persist down to several hundred metres. This is evident from temperature measurements in boreholes in North America, typically, the below-ground temperature varies less from season to season than the air temperature, with mean annual temperatures tending to increase with depth. Thus, if the annual air temperature is only slightly below 0 °C
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Geothermal gradient
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Geothermal gradient is the rate of increasing temperature with respect to increasing depth in the Earths interior. Away from tectonic plate boundaries, it is about 25 °C per km of depth near the surface in most of the world, strictly speaking, geo-thermal necessarily refers to the Earth but the concept may be applied to other planets. A line tracing the gradient through the body is called a geotherm on Earth. On the Moon it is called a selenotherm, the Earths internal heat comes from a combination of residual heat from planetary accretion, heat produced through radioactive decay, and possibly heat from other sources. The major heat-producing isotopes in the Earth are potassium-40, uranium-238, uranium-235, at the center of the planet, the temperature may be up to 7,000 K and the pressure could reach 360 GPa. Temperature within the Earth increases with depth, the heat content of the Earth is 1031 joules. Much of the heat is created by decay of radioactive elements. An estimated 45 to 90 percent of the heat escaping from the Earth originates from decay of elements mainly located in the mantle. Heat of impact and compression released during the formation of the Earth by accretion of in-falling meteorites. Heat released as abundant heavy metals descended to the Earths core, latent heat released as the liquid outer core crystallizes at the inner core boundary. Heat may be generated by tidal force on the Earth as it rotates, since rock cannot flow as readily as water it compresses and distorts, in Earths continental crust, the decay of natural radioactive isotopes has had significant involvement in the origin of geothermal heat. The continental crust is abundant in lower density minerals but also contains significant concentrations of heavier lithophilic minerals such as uranium, because of this, it holds the largest global reservoir of radioactive elements found in the Earth. Especially in layers closer to Earths surface, naturally occurring isotopes are enriched in the granite and these high levels of radioactive elements are largely excluded from the Earths mantle due to their inability to substitute in mantle minerals and consequent enrichment in partial melts. The mantle is made up of high density minerals with high contents of atoms that have relatively small atomic radii such as magnesium, titanium. Heat flows constantly from its sources within the Earth to the surface, total heat loss from the Earth is estimated at 44.2 TW. Mean heat flow is 65 mW/m2 over continental crust and 101 mW/m2 over oceanic crust and this is 0.087 watt/square meter on average, but is much more concentrated in areas where thermal energy is transported toward the crust by convection such as along mid-ocean ridges and mantle plumes. The Earths crust effectively acts as an insulating blanket which must be pierced by fluid conduits in order to release the heat underneath. More of the heat in the Earth is lost through plate tectonics, the final major mode of heat loss is by conduction through the lithosphere, the majority of which occurs in the oceans due to the crust there being much thinner and younger than under the continents
27.
Petroleum geology
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Petroleum geology is the study of origin, occurrence, movement, accumulation, and exploration of hydrocarbon fuels. It refers to the set of geological disciplines that are applied to the search for hydrocarbons. These wells present only a 1-dimensional segment through the Earth and the skill of inferring 3-dimensional characteristics from them is one of the most fundamental in petroleum geology. Recently, the availability of inexpensive, high quality 3D seismic data and data from various electromagnetic geophysical techniques has greatly aided the accuracy of such interpretation, the following section discusses these elements in brief. For a more in-depth treatise, see the second half of this article below, the reservoir is a porous and permeable lithological unit or set of units that holds the hydrocarbon reserves. Analysis of reservoirs at the simplest level requires an assessment of their porosity, some of the key disciplines used in reservoir analysis are the fields of structural analysis, stratigraphy, sedimentology, and reservoir engineering. The seal, or cap rock, is a unit with low permeability that impedes the escape of hydrocarbons from the reservoir rock, common seals include evaporites, chalks and shales. Analysis of seals involves assessment of their thickness and extent, such that their effectiveness can be quantified, the trap is the stratigraphic or structural feature that ensures the juxtaposition of reservoir and seal such that hydrocarbons remain trapped in the subsurface, rather than escaping and being lost. Analysis of maturation involves assessing the history of the source rock in order to make predictions of the amount. Finally, careful studies of migration reveal information on how hydrocarbons move from source to reservoir, several major subdisciplines exist in petroleum geology specifically to study the seven key elements discussed above. In terms of source analysis, several facts need to be established. Firstly, the question of there actually is any source rock in the area must be answered. If the likelihood of there being a rock is thought to be high, the next matter to address is the state of thermal maturity of the source. Maturation of source rocks depends strongly on temperature, such that the majority of oil occurs in the 60° to 120°C range. Gas generation starts at similar temperatures, but may continue up beyond this range, in order to determine the likelihood of oil/gas generation, therefore, the thermal history of the source rock must be calculated. This is performed with a combination of analysis of the source rock and basin modelling methods, such as back-stripping. A full scale basin analysis is carried out prior to defining leads. This study tackles the petroleum system and studies source rock, burial history, maturation, migration and focus, all these elements are used to investigate where potential hydrocarbons might migrate towards
28.
Lubrication
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The lubricant can be a solid, a solid/liquid dispersion, a liquid such as oil or water, a liquid-liquid dispersion or a gas. Lubrication can also describe the phenomenon where reduction of friction occurs unintentionally, the science of friction, lubrication and wear is called tribology. Adequate lubrication allows smooth continuous operation of equipment, reduces the rate of wear, hydrodynamic lubrication is where the motion of the contacting surfaces, and the exact design of the bearing is used to pump lubricant around the bearing to maintain the lubricating film. This design of bearing may wear when started, stopped or reversed, the basis of the hydrodynamic theory of lubrication is the Reynolds equation. The governing equations of the theory of lubrication and some analytical solutions can be found in the reference. Elastohydrodynamic lubrication, Mostly for nonconforming surfaces or higher load conditions, such strain creates a load-bearing area, which provides an almost parallel gap for the fluid to flow through. Much as in hydrodynamic lubrication, the motion of the contacting bodies generates a flow induced pressure, in such high pressure regimes, the viscosity of the fluid may rise considerably. At full film elastohydrodynamic lubrication the generated lubricant film completely separates the surfaces, contact between raised solid features, or asperities, can occur, leading to a mixed-lubrication or boundary lubrication regime. Boundary lubrication, The hydrodynamic effects are negligible, the bodies come into closer contact at their asperities, the heat developed by the local pressures causes a condition which is called stick-slip, and some asperities break off. Boundary lubrication is also defined as that regime in which the load is carried by the surface rather than by the lubricant. Mixed lubrication, This regime is in between the full film elastohydrodynamic and boundary lubrication regimes, the generated lubricant film is not enough to separate the bodies completely, but hydrodynamic effects are considerable. Besides supporting the load the lubricant may have to perform other functions as well, for instance it may cool the contact areas, while carrying out these functions the lubricant is constantly replaced from the contact areas either by the relative movement or by externally induced forces. Lubrication is required for operation of mechanical systems pistons, pumps, cams, bearings, turbines. In some applications, such as engines, the film between the piston and the cylinder wall also seals the combustion chamber, preventing combustion gases from escaping into the crankcase
29.
Fault (geology)
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In geology, a fault is a planar fracture or discontinuity in a volume of rock, across which there has been significant displacement as a result of rock-mass movement. Large faults within the Earths crust result from the action of tectonic forces. Energy release associated with movement on active faults is the cause of most earthquakes. A fault plane is the plane that represents the surface of a fault. A fault trace or fault line is the intersection of a plane with the ground surface. A fault trace is also the line commonly plotted on maps to represent a fault. Since faults do not usually consist of a single, clean fracture, the two sides of a non-vertical fault are known as the hanging wall and footwall. By definition, the wall occurs above the fault plane. This terminology comes from mining, when working a tabular ore body, because of friction and the rigidity of rocks, they cannot glide or flow past each other easily, and occasionally all movement stops. A fault in ductile rocks can also release instantaneously when the rate is too great. The energy released by instantaneous strain-release causes earthquakes, a common phenomenon along transform boundaries, slip is defined as the relative movement of geological features present on either side of a fault plane, and is a displacement vector. A faults sense of slip is defined as the motion of the rock on each side of the fault with respect to the other side. In practice, it is only possible to find the slip direction of faults. Based on direction of slip, faults can be categorized as, strike-slip. Dip-slip, offset is predominantly vertical and/or perpendicular to the fault trace, oblique-slip, combining significant strike and dip slip. The fault surface is usually vertical and the footwall moves either left or right or laterally with very little vertical motion. Strike-slip faults with left-lateral motion are known as sinistral faults. Those with right-lateral motion are known as dextral faults
30.
Mars
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Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, after Mercury. Named after the Roman god of war, it is referred to as the Red Planet because the iron oxide prevalent on its surface gives it a reddish appearance. Mars is a planet with a thin atmosphere, having surface features reminiscent both of the impact craters of the Moon and the valleys, deserts, and polar ice caps of Earth. The rotational period and seasonal cycles of Mars are likewise similar to those of Earth, Mars is the site of Olympus Mons, the largest volcano and second-highest known mountain in the Solar System, and of Valles Marineris, one of the largest canyons in the Solar System. The smooth Borealis basin in the northern hemisphere covers 40% of the planet, Mars has two moons, Phobos and Deimos, which are small and irregularly shaped. These may be captured asteroids, similar to 5261 Eureka, a Mars trojan, there are ongoing investigations assessing the past habitability potential of Mars, as well as the possibility of extant life. Future astrobiology missions are planned, including the Mars 2020 and ExoMars rovers, liquid water cannot exist on the surface of Mars due to low atmospheric pressure, which is about 6⁄1000 that of the Earths, except at the lowest elevations for short periods. The two polar ice caps appear to be largely of water. The volume of ice in the south polar ice cap, if melted. On November 22,2016, NASA reported finding a large amount of ice in the Utopia Planitia region of Mars. The volume of water detected has been estimated to be equivalent to the volume of water in Lake Superior, Mars can easily be seen from Earth with the naked eye, as can its reddish coloring. Its apparent magnitude reaches −2.91, which is surpassed only by Jupiter, Venus, the Moon, optical ground-based telescopes are typically limited to resolving features about 300 kilometers across when Earth and Mars are closest because of Earths atmosphere. Mars is approximately half the diameter of Earth with an area only slightly less than the total area of Earths dry land. Mars is less dense than Earth, having about 15% of Earths volume and 11% of Earths mass, the red-orange appearance of the Martian surface is caused by iron oxide, or rust. It can look like butterscotch, other common colors include golden, brown, tan. Like Earth, Mars has differentiated into a metallic core overlaid by less dense materials. Current models of its interior imply a core with a radius of about 1,794 ±65 kilometers, consisting primarily of iron and this iron sulfide core is thought to be twice as rich in lighter elements than Earths. The core is surrounded by a mantle that formed many of the tectonic and volcanic features on the planet
31.
Jupiter
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Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a giant planet with a mass one-thousandth that of the Sun, Jupiter and Saturn are gas giants, the other two giant planets, Uranus and Neptune are ice giants. Jupiter has been known to astronomers since antiquity, the Romans named it after their god Jupiter. Jupiter is primarily composed of hydrogen with a quarter of its mass being helium and it may also have a rocky core of heavier elements, but like the other giant planets, Jupiter lacks a well-defined solid surface. Because of its rotation, the planets shape is that of an oblate spheroid. The outer atmosphere is visibly segregated into several bands at different latitudes, resulting in turbulence, a prominent result is the Great Red Spot, a giant storm that is known to have existed since at least the 17th century when it was first seen by telescope. Surrounding Jupiter is a faint planetary ring system and a powerful magnetosphere, Jupiter has at least 67 moons, including the four large Galilean moons discovered by Galileo Galilei in 1610. Ganymede, the largest of these, has a greater than that of the planet Mercury. Jupiter has been explored on several occasions by robotic spacecraft, most notably during the early Pioneer and Voyager flyby missions and later by the Galileo orbiter. In late February 2007, Jupiter was visited by the New Horizons probe, the latest probe to visit the planet is Juno, which entered into orbit around Jupiter on July 4,2016. Future targets for exploration in the Jupiter system include the probable ice-covered liquid ocean of its moon Europa, Earth and its neighbor planets may have formed from fragments of planets after collisions with Jupiter destroyed those super-Earths near the Sun. Astronomers have discovered nearly 500 planetary systems with multiple planets, Jupiter moving out of the inner Solar System would have allowed the formation of inner planets, including Earth. Jupiter is composed primarily of gaseous and liquid matter and it is the largest of the four giant planets in the Solar System and hence its largest planet. It has a diameter of 142,984 km at its equator, the average density of Jupiter,1.326 g/cm3, is the second highest of the giant planets, but lower than those of the four terrestrial planets. Jupiters upper atmosphere is about 88–92% hydrogen and 8–12% helium by percent volume of gas molecules, a helium atom has about four times as much mass as a hydrogen atom, so the composition changes when described as the proportion of mass contributed by different atoms. Thus, Jupiters atmosphere is approximately 75% hydrogen and 24% helium by mass, the atmosphere contains trace amounts of methane, water vapor, ammonia, and silicon-based compounds. There are also traces of carbon, ethane, hydrogen sulfide, neon, oxygen, phosphine, the outermost layer of the atmosphere contains crystals of frozen ammonia. The interior contains denser materials - by mass it is roughly 71% hydrogen, 24% helium, through infrared and ultraviolet measurements, trace amounts of benzene and other hydrocarbons have also been found
32.
Europa (moon)
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Europa /jʊˈroʊpə/, is the smallest of the four Galilean moons orbiting Jupiter, and the sixth-closest to the planet. It is also the sixth-largest moon in the Solar System, Europa was discovered in 1610 by Galileo Galilei and was named after Europa, the legendary mother of King Minos of Crete and lover of Zeus. Slightly smaller than Earths Moon, Europa is primarily made of rock and has a water-ice crust. It has an atmosphere composed primarily of oxygen. Its surface is striated by cracks and streaks, whereas craters are relatively rare, in addition to Earth-bound telescope observations, Europa has been examined by a succession of space probe flybys, the first occurring in the early 1970s. Europa has the smoothest surface of any solid object in the Solar System. The apparent youth and smoothness of the surface have led to the hypothesis that a water ocean exists beneath it, sea salt from a subsurface ocean may be coating some geological features on Europa, suggesting that the ocean is interacting with the seafloor. This may be important in determining if Europa could be habitable, in addition, the Hubble Space Telescope detected water vapor plumes similar to those observed on Saturns moon Enceladus, which are thought to be caused by erupting cryogeysers. The Galileo mission, launched in 1989, provides the bulk of current data on Europa, no spacecraft has yet landed on Europa, although there have been several proposed exploration missions. The European Space Agencys Jupiter Icy Moon Explorer is a mission to Ganymede that is due to launch in 2022, NASAs planned Europa Multiple-Flyby Mission will be launched in the mid-2020s. Europa, along with Jupiters three other large moons, Io, Ganymede, and Callisto, was discovered by Galileo Galilei on 8 January 1610, and possibly independently by Simon Marius. The first reported observation of Io and Europa was made by Galileo Galilei on 7 January 1610 using a 20×-magnification refracting telescope at the University of Padua. However, in observation, Galileo could not separate Io and Europa due to the low magnification of his telescope. The following day,8 January 1610, Io and Europa were seen for the first time as separate bodies during Galileos observations of the Jupiter system, Europa is named after Europa, daughter of the king of Tyre, a Phoenician noblewoman in Greek mythology. Like all the Galilean satellites, Europa is named after a lover of Zeus, Europa was courted by Zeus and became the queen of Crete. The naming scheme was suggested by Simon Marius, who discovered the four satellites independently, Marius attributed the proposal to Johannes Kepler. The names fell out of favor for a time and were not revived in general use until the mid-20th century. In much of the astronomical literature, Europa is simply referred to by its Roman numeral designation as Jupiter II or as the second satellite of Jupiter
33.
Water pollution
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Water pollution is the contamination of water bodies. This form of environmental degradation occurs when pollutants are directly or indirectly discharged into water bodies without adequate treatment to remove harmful compounds, Water pollution affects the entire biosphere – plants and organisms living in these bodies of water. In almost all cases the effect is damaging not only to individual species and population, Water pollution is a major global problem which requires ongoing evaluation and revision of water resource policy at all levels. It has been suggested that pollution is the leading worldwide cause of deaths and diseases. An estimated 580 people in India die of water related illness every day. About 90 percent of the water in the cities of China is polluted, as of 2007, half a billion Chinese had no access to safe drinking water. In addition to the problems of water pollution in developing countries. The head of Chinas national development agency said in 2007 that one quarter the length of Chinas seven main rivers were so poisoned the water harmed the skin. Natural phenomena such as volcanoes, algae blooms, storms, and earthquakes also cause changes in water quality. Although interrelated, surface water and groundwater have often studied and managed as separate resources. Surface water seeps through the soil and becomes groundwater, conversely, groundwater can also feed surface water sources. Sources of surface water pollution are generally grouped into two based on their origin. Point source water pollution refers to contaminants that enter a waterway from a single, identifiable source, examples of sources in this category include discharges from a sewage treatment plant, a factory, or a city storm drain. The U. S. Clean Water Act defines point source for regulatory enforcement purposes, the CWA definition of point source was amended in 1987 to include municipal storm sewer systems, as well as industrial storm water, such as from construction sites. Nonpoint source pollution refers to contamination that does not originate from a single discrete source. NPS pollution is often the cumulative effect of small amounts of contaminants gathered from a large area, a common example is the leaching out of nitrogen compounds from fertilized agricultural lands. Nutrient runoff in storm water from sheet flow over a field or a forest are also cited as examples of NPS pollution. Contaminated storm water washed off of parking lots, roads and highways, however, because this runoff is typically channeled into storm drain systems and discharged through pipes to local surface waters, it becomes a point source
34.
Great Lakes
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Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth, containing 21% of the worlds surface fresh water by volume. The total surface is 94,250 square miles, and the volume is 5,439 cubic miles. Due to their sea-like characteristics the five Great Lakes have also long been referred to as inland seas, Lake Superior is the second largest lake in the world by area, and Lake Michigan is the largest lake that is entirely within one country. The southern half of the Great Lakes is bordered by the Great Lakes Megalopolis, the lakes have been a major highway for transportation, migration and trade, and they are home to a large number of aquatic species. Many invasive species have been introduced due to trade, and some threaten the regions biodiversity, though the five lakes reside in separate basins, they form a single, naturally interconnected body of fresh water, within the Great Lakes Basin. The lakes form a chain connecting the interior of North America to the Atlantic Ocean. From the interior to the outlet at the Saint Lawrence River, water flows from Superior to Huron and Michigan, southward to Erie, the lakes drain a large watershed via many rivers, and are studded with approximately 35,000 islands. There are also several smaller lakes, often called inland lakes. The surface area of the five primary lakes combined is roughly equal to the size of the United Kingdom, while the area of the entire basin is about the size of the UK. Lake Michigan is the one of the Great Lakes that is located entirely within the United States. The lakes are divided among the jurisdictions of the Canadian province of Ontario and the U. S. states of Minnesota, Wisconsin, Michigan, Illinois, Indiana, Ohio, Pennsylvania, and New York. Both Ontario and Michigan include in their boundaries portions of four of the lakes, Ontario does not border Lake Michigan, New York and Wisconsins jurisdictions extend into two lakes, and the remaining states into one of the lakes. This designation, however, is not universal and those living on the shore of Lake Superior often refer to all the other lakes as the lower lakes, because they are farther south. This corresponds to thinking of Lakes Erie and Ontario as down south, vessels sailing north on Lake Michigan are considered upbound even though they are sailing toward its effluent current. The Chicago River and Calumet River systems connect the Great Lakes Basin to the Mississippi River System through man-made alterations, the St. Marys River, including the Soo Locks, connects Lake Superior to Lake Huron. The Straits of Mackinac connect Lake Michigan to Lake Huron, the St. Clair River connects Lake Huron to Lake St. Clair. The Detroit River connects Lake St. Clair to Lake Erie, the Niagara River, including Niagara Falls, connects Lake Erie to Lake Ontario. The Welland Canal, bypassing the Falls, connects Lake Erie to Lake Ontario, the Saint Lawrence River connects Lake Ontario to the Gulf of St. Lawrence, which connects to the Atlantic Ocean
35.
Groundwater pollution
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Groundwater pollution occurs when pollutants are released to the ground and make their way down into groundwater. The pollutant creates a contaminant plume within an aquifer, movement of water and dispersion within the aquifer spreads the pollutant over a wider area. The movement of the plume, called a front, may be analyzed through a hydrological transport model or groundwater model. Analysis of groundwater pollution may focus on soil characteristics and site geology, hydrogeology, hydrology, pollution can also occur from naturally occurring contaminants, such as arsenic or fluoride. Using polluted groundwater causes hazards to health through poisoning or the spread of disease. Different mechanisms have influence on the transport of pollutants, e. g. diffusion, adsorption, precipitation, decay, the interaction of groundwater contamination with surface waters is analyzed by use of hydrology transport models. Contaminants found in cover a broad range of physical, inorganic chemical, organic chemical, bacteriological. Principally, many of the pollutants that play a role in surface water pollution may also be found in polluted groundwater. Arsenic and fluoride have been recognized by the World Health Organization as the most serious inorganic contaminants in drinking-water on a worldwide basis, the metalloid arsenic can occur naturally in groundwater, as seen most frequently in Asia, including in China, India and Bangladesh. In the Ganges Plain of northern India and Bangladesh severe contamination of groundwater by naturally occurring arsenic affects 25% of water wells in the shallower of two regional aquifers, arsenic in groundwater can also be present where there are mining operations or mine waste dumps that will leach arsenic. Natural fluoride in groundwater is of growing concern as deeper groundwater is being used, fluoride can especially be released from acidic volcanic rocks and dispersed volcanic ash when water hardness is low. Pathogens contained in feces can lead to groundwater pollution when they are given the opportunity to reach the groundwater, groundwater that is contaminated with pathogens can lead to fatal fecal-oral transmission of diseases. Nitrate is the most common contaminant in the world’s groundwater. In some low-income countries nitrate levels in groundwater are extremely high and it is also stable under high oxygen conditions. Nitrate levels above 10 mg/L in groundwater can cause blue baby syndrome, Drinking water quality standards in the European Union stipulate less than 50 mg/L for nitrate in drinking water. However, the linkages between nitrates in drinking water and blue baby syndrome have been disputed in other studies, the syndrome outbreaks might be due to other factors than elevated nitrate concentrations in drinking water. Elevated nitrate levels in groundwater can be caused by on-site sanitation and it can therefore have an urban or agricultural origin. Volatile organic compounds are a dangerous contaminant of groundwater and they are generally introduced to the environment through careless industrial practices
36.
Sanitary landfill
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A landfill site is a site for the disposal of waste materials by burial and the oldest form of waste treatment. Historically, landfills have been the most common method of organized waste disposal, some landfills are also used for waste management purposes, such as the temporary storage, consolidation and transfer, or processing of waste material. A landfill also may refer to ground that has filled in with rocks instead of waste materials, so that it can be used for a specific purpose. Unless they are stabilized, these areas may experience severe shaking or soil liquefaction of the ground during a large earthquake, afterward, the waste collection vehicles use the existing road network on their way to the tipping face or working front, where they unload their contents. After loads are deposited, compactors or bulldozers can spread and compact the waste on the working face, before leaving the landfill boundaries, the waste collection vehicles may pass through a wheel-cleaning facility. If necessary, they return to the weighbridge for re-weighing without their load, the weighing process can assemble statistics on the daily incoming waste tonnage, which databases can retain for record keeping. In addition to trucks, some landfills may have equipment to handle railroad containers, the use of rail-haul permits landfills to be located at more remote sites, without the problems associated with many truck trips. Typically, in the face, the compacted waste is covered with soil or alternative materials daily. Alternative waste-cover materials include chipped wood or other waste, several sprayed-on foam products, chemically fixed bio-solids. Blankets can be lifted into place at night and then removed the day prior to waste placement. The space that is occupied daily by the waste and the cover material is called a daily cell. Waste compaction is critical to extending the life of the landfill, factors such as waste compressibility, waste-layer thickness and the number of passes of the compactor over the waste affect the waste densities. Landfills are often the most cost-efficient way to dispose of waste, in addition, landfill gas can be upgraded to natural gas—landfill gas utilization—which is a potential revenue stream. Another advantage is having a location for disposal that can be monitored. Landfills have the potential to cause a number of issues, infrastructure disruption, such as damage to access roads by heavy vehicles, may occur. Pollution of local roads and water courses from wheels on vehicles when they leave the landfill can be significant, pollution of the local environment, such as contamination of groundwater or aquifers or soil contamination may occur, as well. Extensive efforts are made to capture and treat leachate from landfills before it reaches groundwater aquifers, eventually, every landfill liner will leak, allowing the leachate to contaminate the groundwater. Installation of composite liners with flexible membrane and soil barrier is enforced by the EPA to ensure that leachate is withheld, rotting food and other decaying organic waste allows methane and carbon dioxide to seep out of the ground and up into the air
37.
Fertilizer
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A fertilizer or fertiliser is any material of natural or synthetic origin that is applied to soils or to plant tissues to supply one or more plant nutrients essential to the growth of plants. Fertilizers enhance the growth of plants and this goal is met in two ways, the traditional one being additives that provide nutrients. The second mode by which some fertilizers act is to enhance the effectiveness of the soil by modifying its water retention and aeration and this article, like many on fertilizers, emphasises the nutritional aspect. The nutrients required for plant life are classified according to the elements. Instead compounds containing these elements are the basis of fertilizers, the macronutrients are consumed in larger quantities and are present in plant tissue in quantities from 0. 15% to 6. 0% on a dry matter basis. Plants are made up of four elements, hydrogen, oxygen, carbon. Carbon, hydrogen and oxygen are widely available as water and carbon dioxide, although nitrogen makes up most of the atmosphere, it is in a form that is unavailable to plants. Nitrogen is the most important fertilizer since nitrogen is present in proteins, DNA, to be nutritious to plants, nitrogen must be made available in a fixed form. Only some bacteria and their host plants can fix atmospheric nitrogen by converting it to ammonia, phosphate is required for the production of DNA and ATP, the main energy carrier in cells, as well as certain lipids. Micronutrients are consumed in quantities and are present in plant tissue on the order of parts-per-million, ranging from 0.15 to 400 ppm DM. These elements are present at the active sites of enzymes that carry out the plants metabolism. Because these elements enable catalysts their impact far exceeds their weight percentage, Fertilizers are classified in several ways. They are classified according to whether they provide a single nutrient, multinutrient fertilizers provide two or more nutrients, for example N and P. Fertilizers are also sometimes classified as inorganic versus organic. Inorganic fertilizers exclude carbon-containing materials except ureas, organic fertilizers are usually plant- or animal-derived matter. Inorganic are sometimes called synthetic fertilizers since various chemical treatments are required for their manufacture, the main nitrogen-based straight fertilizer is ammonia or its solutions. Ammonium nitrate is widely used. Urea is another source of nitrogen, having the advantage that it is solid and non-explosive, unlike ammonia and ammonium nitrate. A few percent of the fertilizer market has been met by calcium ammonium nitrate
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Wastewater
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Wastewater, also written as waste water, is any water that has been adversely affected in quality by anthropogenic influence. Wastewater can originate from a combination of domestic, industrial, commercial or agricultural activities, surface runoff or stormwater, municipal wastewater is usually conveyed in a combined sewer or sanitary sewer, and treated at a wastewater treatment plant. Treated wastewater is discharged into receiving water via an effluent pipe, wastewaters generated in areas without access to centralized sewer systems rely on on-site wastewater systems. These typically comprise a septic tank, drain field, and optionally an on-site treatment unit, the management of wastewater belongs to the overarching term sanitation, just like the management of human excreta, solid waste and stormwater. Sewerage is the infrastructure, including pipes, pumps, screens. Soluble organic material such as urea, fruit sugars, soluble proteins, drugs, pharmaceuticals, inorganic particles such as sand, grit, metal particles, ceramics, etc. Soluble inorganic material such as ammonia, road-salt, sea-salt, cyanide, hydrogen sulfide, thiocyanates, thiosulfates, animals such as protozoa, insects, arthropods, small fish, etc. Macro-solids such as napkins, nappies/diapers, condoms, needles, childrens toys, dead animals or plants. Gases such as sulfide, carbon dioxide, methane, etc. Emulsions such as paints, adhesives, mayonnaise, hair colorants, emulsified oils, toxins such as pesticides, poisons, herbicides, etc. The result is that the content of the water will be decreased. Those biochemical reactions create what is measured in the laboratory as the oxygen demand. Such chemicals are also liable to be broken down using strong oxidizing agents, both the BOD and COD tests are a measure of the relative oxygen-depletion effect of a waste contaminant. Both have been adopted as a measure of pollution effect. The BOD test measures the demand of biodegradable pollutants whereas the COD test measures the oxygen demand of oxidizable pollutants. The so-called 5-day BOD measures the amount of oxygen consumed by oxidation of waste contaminants in a 5-day period. The total amount of consumed when the biochemical reaction is allowed to proceed to completion is called the Ultimate BOD. Because the Ultimate BOD is so time consuming, the 5-day BOD has been almost universally adopted as a measure of pollution effect
39.
Sewage sludge
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Sewage sludge refers to the residual, semi-solid material that is produced as a by-product during sewage treatment of industrial or municipal wastewater. The term septage is also referring to sludge from wastewater treatment but is connected to simple on-site sanitation systems. When fresh sewage or wastewater enters a primary settling tank, approximately 50% of the solid matter will settle out in an hour. This collection of solids is known as raw sludge or primary solids and is said to be fresh before anaerobic processes become active, the sludge will become putrescent in a short time once anaerobic bacteria take over, and must be removed from the sedimentation tank before this happens. This is accomplished in one of two ways, after digesting for an extended period, the result is called digested sludge and may be disposed of by drying and then landfilling. Biosolids is an often used in conjunction with reuse of sewage sludge after sewage sludge treatment. Biosolids can be defined as organic wastewater solids that can be reused after stabilization processes such as anaerobic digestion, opponents of sewage sludge reuse reject this term as a public relations term. Class A sludge is typically dried and pasteurized, and is known as exceptional quality. Class B includes all sludge not classified as Class A, Class B sludge is typically undigested and is volatile. Both classes of sludge may still contain radioactive or pharmaceutical wastes, the amount of sewage sludge produced is proportional to the amount and concentration of wastewater treated, and it also depends on the type of wastewater treatment process used. It can be expressed as kg dry solids per cubic metre of wastewater treated, the total sludge production from a wastewater treatment process is the sum of sludge from primary settling tanks plus excess sludge from the biological treatment step. For example, primary sedimentation produces about 110–170 kg/ML of so-called primary sludge, the sludge production is expressed as kg of dry solids produced per ML of wastewater treated, one mega litre is 103 m3. United States municipal wastewater treatment plants in 1997 produced about 7.7 million dry tons of sewage sludge, as of 2002, about 60% of all sewage sludge was applied to land as a soil amendment and fertilizer for growing crops. Bacteria in Class A sludge products can actually regrow under certain environmental conditions, Pathogens could easily remain undetected in untreated sewage sludge. Pathogens are not a significant health issue if sewage sludge is properly treated, micro-pollutants can become concentrated in sewage sludge. Each of these disposal options comes with a myriad of potential — and in some cases proven — human health, high levels of sterols and other hormones have been detected, with averages in the range of up to 1,000,000 µg/kg sludge. One of the concerns in the treated sludge is the concentrated metals content. Leaching methods can be used to reduce the content and meet the regulatory limit
40.
Septic tank
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Other components may include pumps, alarms, sand filters, and clarified liquid effluent disposal methods such as a septic drain field, ponds, natural stone fiber filter plants or peat moss beds. Septic systems are a type of onsite sewage facility, in North America, approximately 25 percent of the population relies on septic tanks, including some suburbs and small towns as well as rural areas. Indianapolis is one example of a city where many of the citys neighborhoods still rely on separate septic systems. In Europe, septic systems are limited to rural areas. Since septic systems require large drainfields, they are not suitable for densely built cities, the term septic refers to the anaerobic bacterial environment that develops in the tank which decomposes or mineralizes the waste discharged into the tank. Septic tanks can be coupled with other onsite wastewater treatment units such as biofilters or aerobic systems involving artificially forced aeration, periodic preventive maintenance is required to remove solids that remain and gradually fill the tank, reducing its efficiency. Maintenance requires regular pumping to remove these, according to the US Environmental Protection Agency, in the United States it is the home owners responsibility to maintain their septic systems. Anyone who disregards this requirement will eventually be faced with costly repairs when solids escape the tank and clog the clarified liquid effluent disposal system. A septic tank consists of one or more concrete or plastic tanks of between 4000 and 7500 liters, one end is connected to a wastewater pipe and the other to a septic drain field. Generally these pipe connections are made with a T pipe, allowing liquid to enter, wastewater enters the first chamber of the tank, allowing solids to settle and scum to float. The settled solids are anaerobically digested, reducing the volume of solids, the liquid component flows through the dividing wall into the second chamber, where further settlement takes place. A percolation test is required prior to installation to ensure the porosity of the soil is adequate to serve as a drain field, a piping network, often laid in a stone-filled trench, distributes the wastewater throughout the field with multiple drainage holes in the network. The size of the field is proportional to the volume of wastewater. The entire septic system can operate by gravity alone or, where topographic considerations require, certain septic tank designs include siphons or other devices to increase the volume and velocity of outflow to the drainage field. These help to fill the pipe more evenly and extend the drainage field life by preventing premature clogging or bioclogging. An Imhoff tank is a septic system where the sludge is digested in a separate tank. This avoids mixing digested sludge with incoming sewage, also, some septic tank designs have a second stage where the effluent from the anaerobic first stage is aerated before it drains into the seepage field. A properly designed and normally operating septic system is odor-free and, besides periodic inspection and emptying of the septic tank, a well designed and maintained concrete, fiberglass, or plastic tank should last about 50 years
41.
Ogallala Aquifer
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The Ogallala Aquifer is a shallow water table aquifer surrounded by sand, silt, clay and gravel located beneath the Great Plains in the United States. One of the worlds largest aquifers, it underlies an area of approximately 174,000 sq mi in portions of eight states and it was named in 1898 by geologist N. H. Darton from its type locality near the town of Ogallala, Nebraska. The aquifer is part of the High Plains Aquifer System, and rests on the Ogallala Formation, large scale extraction for agricultural purposes started after World War II due partially to center pivot technology and to the adaptation of automotive engines for groundwater wells. Today about 27% of the land in the entire United States lies over the aquifer. The aquifer is at risk for over-extraction and pollution, since 1950, agricultural irrigation has reduced the saturated volume of the aquifer by an estimated 9%. Once depleted, the aquifer will take over 6,000 years to replenish naturally through rainfall, the aquifer system supplies drinking water to 82% of the 2.3 million people who live within the boundaries of the High Plains study area. The deposition of material dates back two to six million years, from the late Miocene to early Pliocene ages when the southern Rocky Mountains were still tectonically active. From the uplands to the west, rivers and streams cut channels in a generally west to east or southeast direction, in that respect, the process is similar to those currently prevailing in other modern rivers of the area, such as the Kansas River and its tributaries. The major differences are time and depth, the depth of the Ogallala varies with the shape of then-prevailing surface, being deepest where it fills ancient valleys and channels. The Ogallala Formation consists mostly of sedimentary rocks in its deeper sections. The water-saturated thickness of the Ogallala Formation ranges from a few feet to more than 1000 feet and is greater in the Northern Plains. The depth of the water below the surface of the ranges from almost 400 feet in parts of the north to between 100 and 200 feet throughout much of the south. Groundwater within the Ogallala generally flows from west to east at a rate of a foot per day. Hydraulic conductivity, or the ability for a fluid to move through porous material, water quality within the Ogallala varies with the highest quality for drinking and irrigation in the northern region while the southern region had the poorest. Human and natural processes over the past 60 to 70 years, including density, climate. Nitrate levels generally meet USGS water quality standards, but continue to increase over time. This trend can impact the future groundwater sustainability for portions of the aquifer, an aquifer is a groundwater storage reservoir in the water cycle. While groundwater is a source, reserves replenish relatively slowly
42.
Artesian aquifer
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See Great Artesian Basin for the water source in Australia. An artesian aquifer is a confined aquifer containing groundwater under positive pressure and this causes the water level in a well to rise to a point where hydrostatic equilibrium has been reached. A well drilled into such an aquifer is called an artesian well, if water reaches the ground surface under the natural pressure of the aquifer, the well is called a flowing artesian well. An aquifer is a layer of porous and permeable material such as sand and gravel, limestone, or sandstone. An artesian aquifer is confined between impermeable rocks or clay which causes this positive pressure, not all the aquifers are artesian, because the water table must reach the surface. The recharging of aquifers happens when the table at its recharge zone is at a higher elevation than the head of the well. Fossil water aquifers can also be if they are under sufficient pressure from the surrounding rocks. This is similar to how many newly tapped oil wells are pressurized, Artesian wells were named after the former province of Artois in France, where many artesian wells were drilled by Carthusian monks from 1126. Fluid mechanics Great Artesian Basin Hydrogeology Qanat Video of an artesian aquifer releasing water under its own pressure
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Valley
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A valley is a low area between hills, often with a river running through it. In geology, a valley or dale is a depression that is longer than it is wide, the terms U-shaped and V-shaped are descriptive terms of geography to characterize the form of valleys. Most valleys belong to one of two main types or a mixture of them, with respect to the cross section of the slopes or hillsides. A valley in its broadest geographic sense is known as a dale. A valley through which a river runs may also be referred to as a vale, a small, secluded, and often wooded valley is known as a dell or in Scotland as a glen. A wide, flat valley through which a river runs is known in Scotland as a strath, a mountain cove is a small valley, closed at one or both ends, in the central or southern Appalachian Mountains which sometimes results from the erosion of a geologic window. A small valley surrounded by mountains or ridges is sometimes known as a hollow, a deep, narrow valley is known as a cwm. Similar geological structures, such as canyons, ravines, gorges, gullies, chines, a valley formed by erosion is called an erosional valley, a valley formed by geologic events such as drop faults or the rise of highlands is called a structural valley. A valley formed by flowing water, or river valley, is usually V-shaped, the exact shape will depend on the characteristics of the stream flowing through it. Rivers with steep gradients, as in mountain ranges, produce steep walls, shallower slopes may produce broader and gentler valleys. However, in the lowest stretch of a river, where it approaches its base level, it begins to deposit sediment, in prehistory, the rivers were used as a source of fresh water and food, as well as a place to wash and a sewer. The proximity of water moderated temperature extremes and provided a source for irrigation, most of the first civilizations developed from these river valley communities. In geography, a vale is a river valley, usually with a particularly wide flood plain or flat valley bottom. In Southern England, vales commonly occur between the escarpment slopes of pairs of chalk formations, where the dome has been eroded, exposing less resistant underlying rock. Rift valleys, such as the Albertine Rift, are formed by the expansion of the Earths crust due to tectonic activity beneath the Earths surface, there are various forms of valley associated with glaciation that may be referred to as glacial valleys. A valley carved by glaciers is normally U-shaped, the valley becomes visible upon the recession of the glacier that forms it. When the ice recedes or thaws, the remains, often littered with small boulders that were transported within the ice. Floor gradient does not affect the shape, it is the glaciers size that does
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Heat capacity
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Heat capacity or thermal capacity is a measurable physical quantity equal to the ratio of the heat added to an object to the resulting temperature change. The unit of capacity is joule per kelvin J K. Specific heat is the amount of heat needed to raise the temperature of one kilogram of mass by 1 kelvin, Heat capacity is an extensive property of matter, meaning it is proportional to the size of the system. The molar heat capacity is the capacity per unit amount of a pure substance. In some engineering contexts, the heat capacity is used. Other contributions can come from magnetic and electronic degrees of freedom in solids, for quantum mechanical reasons, at any given temperature, some of these degrees of freedom may be unavailable, or only partially available, to store thermal energy. In such cases, the capacity is a fraction of the maximum. As the temperature approaches zero, the heat capacity of a system approaches zero. Quantum theory can be used to predict the heat capacity of simple systems. In a previous theory of common in the early modern period, heat was thought to be a measurement of an invisible fluid. Bodies were capable of holding an amount of this fluid, hence the term heat capacity, named. Heat is no longer considered a fluid, but rather a transfer of disordered energy, nevertheless, at least in English, the term heat capacity survives. In some other languages, the thermal capacity is preferred. In the International System of Units, heat capacity has the unit joules per kelvin, if the temperature change is sufficiently small the heat capacity may be assumed to be constant, C = Q Δ T. Heat capacity is a property, meaning it depends on the extent or size of the physical system studied. A sample containing twice the amount of substance as another sample requires the transfer of twice the amount of heat to achieve the change in temperature. For many purposes it is convenient to report heat capacity as an intensive property. In practice, this is most often an expression of the property in relation to a unit of mass, in science and engineering, International standards now recommend that specific heat capacity always refer to division by mass
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Heat pump
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A heat pump is a device that transfers heat energy from a source of heat to a destination called a heat sink. Heat pumps are designed to move energy in the opposite direction of spontaneous heat transfer by absorbing heat from a cold space. A heat pump uses a small amount of power to accomplish the work of transferring energy from the heat source to the heat sink. While air conditioners and freezers are familiar examples of heat pumps, in this use, heat pumps generally draw heat from the cooler external air or from the ground. In heating mode, heat pumps are three to four times more effective at heating than simple electrical resistance heaters using the amount of electricity. Typically installed cost for a pump is about 20 times greater than for resistance heaters. Heat energy naturally transfers from warmer places to colder spaces, however, a heat pump can reverse this by absorbing heat from a cold space and releasing it to a warmer one. Heat is not conserved in this process and requires some amount of energy such as electricity. These heat pumps can be reversible, and work in either direction to provide heating or cooling to the internal space, heat pumps are used to transfer heat because less high-grade energy is required than is released as heat. Most of the energy for heating comes from the external environment, heat pumps use a refrigerant as an intermediate fluid to absorb heat where it vaporizes, in the evaporator, and then to release heat where the refrigerant condenses, in the condenser. The refrigerant flows through insulated pipes between the evaporator and the condenser, allowing for efficient thermal energy transfer at relatively long distances, reversible heat pumps work in either direction to provide heating or cooling to the internal space. They employ a valve to reverse the flow of refrigerant from the compressor through the condenser. In heating mode, the coil is an evaporator, while the indoor is a condenser. The refrigerant flowing from the evaporator carries the energy from outside air indoors. Vapor temperature is augmented within the pump by compressing it, the indoor coil then transfers thermal energy to the indoor air, which is then moved around the inside of the building by an air handler. Alternatively, thermal energy is transferred to water, which is used to heat the building via radiators or underfloor heating. The heated water may also be used for hot water consumption. The refrigerant is then allowed to expand, cool, and absorb heat from the temperature in the outside evaporator
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Water cycle
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The water cycle, also known as the hydrological cycle or the hydrologic cycle, describes the continuous movement of water on, above and below the surface of the Earth. In doing so, the water goes through different forms, liquid, solid, the water cycle involves the exchange of energy, which leads to temperature changes. For instance, when water evaporates, it takes up energy from its surroundings, when it condenses, it releases energy and warms the environment. The evaporative phase of the cycle purifies water which then replenishes the land with freshwater, the flow of liquid water and ice transports minerals across the globe. It is also involved in reshaping the geological features of the Earth, the water cycle is also essential for the maintenance of most life and ecosystems on the planet. The sun, which drives the cycle, heats water in oceans. Water evaporates as water vapor into the air, ice and snow can sublimate directly into water vapour. Evapotranspiration is water transpired from plants and evaporated from the soil, the water vapour molecule H 2O has less density compared to the major components of the atmosphere, nitrogen and oxygen, N2 andO2. Due to the significant difference in mass, water vapor in gas form gains height in open air as a result of buoyancy. However, as increases, air pressure decreases and the temperature drops. The lowered temperature causes water vapour to condense into a liquid water droplet which is heavier than the air. A huge concentration of these droplets over a space up in the atmosphere become visible as cloud. Fog is formed if the water vapour condenses near ground level, as a result of moist air, air currents move water vapour around the globe, cloud particles collide, grow, and fall out of the upper atmospheric layers as precipitation. Some precipitation falls as snow or hail, sleet, and can accumulate as ice caps and glaciers, most water falls back into the oceans or onto land as rain, where the water flows over the ground as surface runoff. A portion of runoff enters rivers in valleys in the landscape, runoff and water emerging from the ground may be stored as freshwater in lakes. Not all runoff flows into rivers, much of it soaks into the ground as infiltration, some water infiltrates deep into the ground and replenishes aquifers, which can store freshwater for long periods of time. Some infiltration stays close to the surface and can seep back into surface-water bodies as groundwater discharge. Some groundwater finds openings in the surface and comes out as freshwater springs
