Hydrogeology ( hydro- meaning water, and -geology meaning the study of the Earth ) is the area of geology that deals with the distribution and movement of groundwater in the soil and rocks of the Earth's crust (commonly in aquifers ). The terms groundwater hydrology , geohydrology , and hydrogeology are often used interchangeably, though hydrogeology is the most commonly used.
124-723: Hydrogeology is the study of the laws governing the movement of subterranean water, the mechanical, chemical, and thermal interaction of this water with the porous solid, and the transport of energy, chemical constituents, and particulate matter by flow (Domenico and Schwartz, 1998). Groundwater engineering , another name for hydrogeology, is a branch of engineering which is concerned with groundwater movement and design of wells , pumps , and drains. The main concerns in groundwater engineering include groundwater contamination , conservation of supplies, and water quality . Wells are constructed for use in developing nations, as well as for use in developed nations in places which are not connected to
248-590: A Reynolds number less than unity); many of the empirically derived laws of groundwater flow can be alternately derived in fluid mechanics from the special case of Stokes flow (viscosity and pressure terms, but no inertial term). The mathematical relationships used to describe the flow of water through porous media are Darcy's law , the diffusion , and Laplace equations, which have applications in many diverse fields. Steady groundwater flow (Laplace equation) has been simulated using electrical , elastic , and heat conduction analogies. Transient groundwater flow
372-635: A Taylor series ). For example, the first-order time derivative is often approximated using the following forward finite difference, where the subscripts indicate a discrete time location, Engineering Engineering is the practice of using natural science , mathematics , and the engineering design process to solve technical problems, increase efficiency and productivity, and improve systems. Modern engineering comprises many subfields which include designing and improving infrastructure , machinery , vehicles , electronics , materials , and energy systems. The discipline of engineering encompasses
496-559: A biome classification, as climate is a major influence on life in a region. One of the most used is the Köppen climate classification scheme first developed in 1899. There are several ways to classify climates into similar regimes. Originally, climes were defined in Ancient Greece to describe the weather depending upon a location's latitude. Modern climate classification methods can be broadly divided into genetic methods, which focus on
620-510: A 30-year period. A 30-year period is used as it is long enough to filter out any interannual variation or anomalies such as El Niño–Southern Oscillation , but also short enough to be able to show longer climatic trends." The WMO originated from the International Meteorological Organization which set up a technical commission for climatology in 1929. At its 1934 Wiesbaden meeting, the technical commission designated
744-400: A French scientist who made advances in flow of fluids through porous materials. He conducted experiments which studied the movement of fluids through sand columns. These experiments led to the determination of Darcy's law , which describes fluid flow through a medium with high levels of porosity. Darcy's work is considered to be the beginning of quantitative hydrogeology. Oscar Edward Meinzer
868-694: A broad range of more specialized fields of engineering , each with a more specific emphasis on particular areas of applied mathematics , applied science , and types of application. See glossary of engineering . The term engineering is derived from the Latin ingenium , meaning "cleverness". The American Engineers' Council for Professional Development (ECPD, the predecessor of ABET ) has defined "engineering" as: The creative application of scientific principles to design or develop structures, machines, apparatus, or manufacturing processes, or works utilizing them singly or in combination; or to construct or operate
992-525: A broader sense, climate is the state of the components of the climate system , including the atmosphere , hydrosphere , cryosphere , lithosphere and biosphere and the interactions between them. The climate of a location is affected by its latitude , longitude , terrain , altitude , land use and nearby water bodies and their currents. Climates can be classified according to the average and typical variables, most commonly temperature and precipitation . The most widely used classification scheme
1116-411: A city water system. Wells are designed and maintained to uphold the integrity of the aquifer, and to prevent contaminants from reaching the groundwater. Controversy arises in the use of groundwater when its usage impacts surface water systems, or when human activity threatens the integrity of the local aquifer system. Hydrogeology is an interdisciplinary subject; it can be difficult to account fully for
1240-407: A commercial scale, such as the manufacture of commodity chemicals , specialty chemicals , petroleum refining , microfabrication , fermentation , and biomolecule production . Civil engineering is the design and construction of public and private works, such as infrastructure (airports, roads, railways, water supply, and treatment etc.), bridges, tunnels, dams, and buildings. Civil engineering
1364-405: A common 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 ( water table aquifers), and either saturated or unsaturated; the type of aquifer affects what properties control
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#17328527308431488-501: A corresponding steady-state simulation (where the time derivative in the groundwater flow equation is set equal to 0). There are two broad categories of how the (PDE) would be solved; either analytical methods, numerical methods, or something possibly in between. Typically, analytic methods solve the groundwater flow equation under a simplified set of conditions exactly , while numerical methods solve it under more general conditions to an approximation . Analytic methods typically use
1612-533: A count of 2,000. There were fewer than 50 engineering graduates in the U.S. before 1865. In 1870 there were a dozen U.S. mechanical engineering graduates, with that number increasing to 43 per year in 1875. In 1890, there were 6,000 engineers in civil, mining , mechanical and electrical. There was no chair of applied mechanism and applied mechanics at Cambridge until 1875, and no chair of engineering at Oxford until 1907. Germany established technical universities earlier. The foundations of electrical engineering in
1736-420: A demand for machinery with metal parts, which led to the development of several machine tools . Boring cast iron cylinders with precision was not possible until John Wilkinson invented his boring machine , which is considered the first machine tool . Other machine tools included the screw cutting lathe , milling machine , turret lathe and the metal planer . Precision machining techniques were developed in
1860-419: A few global datasets exist. Global climate models can be dynamically or statistically downscaled to regional climate models to analyze impacts of climate change on a local scale. Examples are ICON or mechanistically downscaled data such as CHELSA (Climatologies at high resolution for the earth's land surface areas). The most talked-about applications of these models in recent years have been their use to infer
1984-459: A poor aquifer. Porosity does not directly affect the distribution of hydraulic head in an aquifer, but it has a very strong effect on the migration of dissolved contaminants, since it affects groundwater flow velocities through an inversely proportional relationship. Darcy's law is commonly applied to study the movement of water, or other fluids through porous media, and constitutes the basis for many hydrogeological analyses. Water content ( θ )
2108-551: A preferential path in one direction, some other in a different direction, so that the contaminant can be spread in a completely irregular way, like in a (three-dimensional) delta of a river. Dispersivity is actually a factor which represents our lack of information about the system we are simulating. There are many small details about the aquifer which are effectively averaged when using a macroscopic approach (e.g., tiny beds of gravel and clay in sand aquifers); these manifest themselves as an apparent dispersivity. Because of this, α
2232-400: A result, many engineers continue to learn new material throughout their careers. If multiple solutions exist, engineers weigh each design choice based on their merit and choose the solution that best matches the requirements. The task of the engineer is to identify, understand, and interpret the constraints on a design in order to yield a successful result. It is generally insufficient to build
2356-435: A soil particle, must choose where to go, whether left or right or up or down, so that the water "particles" (and their solute) are gradually spread in all directions around the mean path. This is the "microscopic" mechanism, on the scale of soil particles. More important, over long distances, can be the macroscopic inhomogeneities of the aquifer, which can have regions of larger or smaller permeability, so that some water can find
2480-411: A technically successful product, rather, it must also meet further requirements. Constraints may include available resources, physical, imaginative or technical limitations, flexibility for future modifications and additions, and other factors, such as requirements for cost, safety , marketability, productivity, and serviceability . By understanding the constraints, engineers derive specifications for
2604-618: A testament to the ingenuity and skill of ancient civil and military engineers. Other monuments, no longer standing, such as the Hanging Gardens of Babylon and the Pharos of Alexandria , were important engineering achievements of their time and were considered among the Seven Wonders of the Ancient World . The six classic simple machines were known in the ancient Near East . The wedge and
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#17328527308432728-445: A unit depressurization of a confined aquifer. They are fractions between 0 and 1. Specific yield ( S y ) is also a ratio between 0 and 1 ( S y ≤ porosity) and indicates the amount of water released due to drainage from lowering the water table in an unconfined aquifer. The value for specific yield is less than the value for porosity because some water will remain in the medium even after drainage due to intermolecular forces. Often
2852-909: A useful purpose. Examples of bioengineering research include bacteria engineered to produce chemicals, new medical imaging technology, portable and rapid disease diagnostic devices, prosthetics, biopharmaceuticals, and tissue-engineered organs. Interdisciplinary engineering draws from more than one of the principle branches of the practice. Historically, naval engineering and mining engineering were major branches. Other engineering fields are manufacturing engineering , acoustical engineering , corrosion engineering , instrumentation and control , aerospace , automotive , computer , electronic , information engineering , petroleum , environmental , systems , audio , software , architectural , agricultural , biosystems , biomedical , geological , textile , industrial , materials , and nuclear engineering . These and other branches of engineering are represented in
2976-622: A way to distinguish between those specializing in the construction of such non-military projects and those involved in the discipline of military engineering . The pyramids in ancient Egypt , ziggurats of Mesopotamia , the Acropolis and Parthenon in Greece, the Roman aqueducts , Via Appia and Colosseum, Teotihuacán , and the Brihadeeswarar Temple of Thanjavur , among many others, stand as
3100-410: A well is a hydrograph or, the changes in hydraulic head recorded during the pumping of a well in a test are called drawdown . Porosity ( n ) is a directly measurable aquifer property; it is a fraction between 0 and 1 indicating the amount of pore space between unconsolidated soil particles or within a fractured rock. Typically, the majority of groundwater (and anything dissolved in it) moves through
3224-437: A well). Intrinsic permeability ( κ ) is a property of the porous medium alone, and does not change with different fulids (e.g. different density or viscosity; it is used more in the petroleum industry. Specific storage ( S s ) and its depth-integrated equivalent, storativity ( S=S s b ), are indirect aquifer properties (they cannot be measured directly); they indicate the amount of groundwater released from storage due to
3348-403: A wider sense is the state, including a statistical description, of the climate system." The World Meteorological Organization (WMO) describes " climate normals " as "reference points used by climatologists to compare current climatological trends to that of the past or what is considered typical. A climate normal is defined as the arithmetic average of a climate element (e.g. temperature) over
3472-513: Is a broad discipline that is often broken down into several sub-disciplines. Although an engineer will usually be trained in a specific discipline, he or she may become multi-disciplined through experience. Engineering is often characterized as having four main branches: chemical engineering, civil engineering, electrical engineering, and mechanical engineering. Chemical engineering is the application of physics, chemistry, biology, and engineering principles in order to carry out chemical processes on
3596-461: Is a groundwater flow equation applied to subsurface drainage by pipes, tile drains or ditches. An alternative subsurface drainage method is drainage by wells for which groundwater flow equations are also available. To use the groundwater flow equation to estimate the distribution of hydraulic heads, or the direction and rate of groundwater flow, this partial differential equation (PDE) must be solved. The most common means of analytically solving
3720-401: Is also a directly measurable property; it is the fraction of the total rock which is filled with liquid water. This is also a fraction between 0 and 1, but it must also be less than or equal to the total porosity. The water content is very important in vadose zone hydrology, where the hydraulic conductivity is a strongly nonlinear function of water content; this complicates the solution of
3844-453: Is an empirical factor which quantifies how much contaminants stray away from the path of the groundwater which is carrying it. Some of the contaminants will be "behind" or "ahead" the mean groundwater, giving rise to a longitudinal dispersivity (α L ), and some will be "to the sides of" the pure advective groundwater flow, leading to a transverse dispersivity (α T ). Dispersion in groundwater arises because each water "particle", passing beyond
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3968-517: Is an important phenomenon for small distances (it is essential for the achievement of thermodynamic equilibria ), but, as the time necessary to cover a distance by diffusion is proportional to the square of the distance itself, it is less effective for spreading a solute over macroscopic distances on a short time scale. The diffusion coefficient , D , is typically quite small, and its effect can often be neglected (unless groundwater flow velocities are extremely low, as they are in clay aquitards ). It
4092-418: Is analogous to the retardation factor of chromatography . Unlike diffusion and dispersion, which simply spread the contaminant, the retardation factor changes its global average velocity , so that it can be much slower than that of water. This is due to a chemico-physical effect: the adsorption to the soil, which holds the contaminant back and does not allow it to progress until the quantity corresponding to
4216-653: Is analogous to the diffusion of heat in a solid, therefore some solutions to hydrological problems have been adapted from heat transfer literature. Traditionally, the movement of groundwater has been studied separately from surface water, climatology , and even the chemical and microbiological aspects of hydrogeology (the processes are uncoupled). As the field of hydrogeology matures, the strong interactions between groundwater, surface water , water chemistry , soil moisture, and even climate are becoming more clear. California and Washington both require special certification of hydrogeologists to offer professional services to
4340-549: Is as follows: "Climate in a narrow sense is usually defined as the "average weather", or more rigorously, as the statistical description in terms of the mean and variability of relevant quantities over a period ranging from months to thousands or millions of years. The classical period is 30 years, as defined by the World Meteorological Organization (WMO). These quantities are most often surface variables such as temperature, precipitation, and wind. Climate in
4464-730: Is associated with anything constructed on or within the Earth. This discipline applies geological sciences and engineering principles to direct or support the work of other disciplines such as civil engineering , environmental engineering , and mining engineering . Geological engineers are involved with impact studies for facilities and operations that affect surface and subsurface environments, such as rock excavations (e.g. tunnels ), building foundation consolidation, slope and fill stabilization, landslide risk assessment, groundwater monitoring, groundwater remediation , mining excavations, and natural resource exploration. One who practices engineering
4588-497: Is called an engineer , and those licensed to do so may have more formal designations such as Professional Engineer , Chartered Engineer , Incorporated Engineer , Ingenieur , European Engineer , or Designated Engineering Representative . In the engineering design process, engineers apply mathematics and sciences such as physics to find novel solutions to problems or to improve existing solutions. Engineers need proficient knowledge of relevant sciences for their design projects. As
4712-484: Is composed of pressure head ( ψ ) and elevation head ( z ). The head gradient is the change in hydraulic head per length of flowpath, and appears in Darcy's law as being proportional to the discharge. Hydraulic head is a directly measurable property that can take on any value (because of the arbitrary datum involved in the z term); ψ can be measured with a pressure transducer (this value can be negative, e.g., suction, but
4836-462: Is discussed in terms of global warming , which results in redistributions of biota . For example, as climate scientist Lesley Ann Hughes has written: "a 3 °C [5 °F] change in mean annual temperature corresponds to a shift in isotherms of approximately 300–400 km [190–250 mi] in latitude (in the temperate zone) or 500 m [1,600 ft] in elevation. Therefore, species are expected to move upwards in elevation or towards
4960-422: Is important not to confuse diffusion with dispersion, as the former is a physical phenomenon and the latter is an empirical hydrodynamic factor which is cast into a similar form as diffusion, because its a convenient way to mathematically describe and solve the question. The retardation factor is another very important feature that make the motion of the contaminant to deviate from the average groundwater motion. It
5084-432: Is often claimed to be dependent on the length scale of the problem — the dispersivity found for transport through 1 m of aquifer is different from that for transport through 1 cm of the same aquifer material. Diffusion is a fundamental physical phenomenon, which Albert Einstein characterized as Brownian motion , that describes the random thermal movement of molecules and small particles in gases and liquids. It
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5208-419: Is often derived from a physical basis using Darcy's law and a conservation of mass for a small control volume. The equation is often used to predict flow to wells , which have radial symmetry, so the flow equation is commonly solved in polar or cylindrical coordinates . The Theis equation is one of the most commonly used and fundamental solutions to the groundwater flow equation; it can be used to predict
5332-468: Is positive in saturated aquifers), and z can be measured relative to a surveyed datum (typically the top of the well casing). Commonly, in wells tapping unconfined aquifers the water level in a well is used as a proxy for hydraulic head, assuming there is no vertical gradient of pressure. Often only changes in hydraulic head through time are needed, so the constant elevation head term can be left out ( Δh = Δψ ). A record of hydraulic head through time at
5456-558: Is the Köppen climate classification . The Thornthwaite system , in use since 1948, incorporates evapotranspiration along with temperature and precipitation information and is used in studying biological diversity and how climate change affects it. The major classifications in Thornthwaite's climate classification are microthermal, mesothermal, and megathermal. Finally, the Bergeron and Spatial Synoptic Classification systems focus on
5580-428: Is the design and manufacture of physical or mechanical systems, such as power and energy systems, aerospace / aircraft products, weapon systems , transportation products, engines , compressors , powertrains , kinematic chains , vacuum technology, vibration isolation equipment, manufacturing , robotics, turbines, audio equipments, and mechatronics . Bioengineering is the engineering of biological systems for
5704-432: Is the prediction of future behavior of an aquifer system, based on analysis of past and present observations. Some hypothetical, but characteristic questions asked would be: Most of these questions can be addressed through simulation of the hydrologic system (using numerical models or analytic equations). Accurate simulation of the aquifer system requires knowledge of the aquifer properties and boundary conditions. Therefore,
5828-664: Is traditionally broken into a number of sub-disciplines, including structural engineering , environmental engineering , and surveying . It is traditionally considered to be separate from military engineering . Electrical engineering is the design, study, and manufacture of various electrical and electronic systems, such as broadcast engineering , electrical circuits , generators , motors , electromagnetic / electromechanical devices, electronic devices , electronic circuits , optical fibers , optoelectronic devices , computer systems, telecommunications , instrumentation , control systems , and electronics . Mechanical engineering
5952-406: Is what you expect, weather is what you get." Over historical time spans, there are a number of nearly constant variables that determine climate, including latitude , altitude, proportion of land to water, and proximity to oceans and mountains. All of these variables change only over periods of millions of years due to processes such as plate tectonics . Other climate determinants are more dynamic:
6076-831: The Neo-Assyrian period (911–609) BC. The Egyptian pyramids were built using three of the six simple machines, the inclined plane, the wedge, and the lever, to create structures like the Great Pyramid of Giza . The earliest civil engineer known by name is Imhotep . As one of the officials of the Pharaoh , Djosèr , he probably designed and supervised the construction of the Pyramid of Djoser (the Step Pyramid ) at Saqqara in Egypt around 2630–2611 BC. The earliest practical water-powered machines,
6200-542: The Newcomen steam engine . Smeaton designed the third Eddystone Lighthouse (1755–59) where he pioneered the use of ' hydraulic lime ' (a form of mortar which will set under water) and developed a technique involving dovetailed blocks of granite in the building of the lighthouse. He is important in the history, rediscovery of, and development of modern cement , because he identified the compositional requirements needed to obtain "hydraulicity" in lime; work which led ultimately to
6324-451: The U.S. Army Corps of Engineers . The word "engine" itself is of even older origin, ultimately deriving from the Latin ingenium ( c. 1250 ), meaning "innate quality, especially mental power, hence a clever invention." Later, as the design of civilian structures, such as bridges and buildings, matured as a technical discipline, the term civil engineering entered the lexicon as
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#17328527308436448-427: The chemical , physical , biological , and even legal interactions between soil , water , nature , and society . 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 (flow from high pressure to low), often through fractures and conduits in circuitous paths. Taking into account
6572-436: The divergence theorem ). This results in a system which overall approximates the groundwater flow equation, but exactly matches the boundary conditions (the head or flux is specified in the elements which intersect the boundaries). Finite differences are a way of representing continuous differential operators using discrete intervals ( Δx and Δt ), and the finite difference methods are based on these (they are derived from
6696-532: The groundwater flow equation , typically used to analyze the results of an aquifer test or slug test . The topic of numerical methods is quite large, obviously being of use to most fields of engineering and science in general. Numerical methods have been around much longer than computers have (In the 1920s Richardson developed some of the finite difference schemes still in use today, but they were calculated by hand, using paper and pencil, by human "calculators"), but they have become very important through
6820-411: The hydraulic gradient , and the hydraulic conductivity . The groundwater flow equation, in its most general form, describes the movement of groundwater in a porous medium (aquifers and aquitards). It is known in mathematics as the diffusion equation , and has many analogs in other fields. Many solutions for groundwater flow problems were borrowed or adapted from existing heat transfer solutions. It
6944-517: The inclined plane (ramp) were known since prehistoric times. The wheel , along with the wheel and axle mechanism, was invented in Mesopotamia (modern Iraq) during the 5th millennium BC. The lever mechanism first appeared around 5,000 years ago in the Near East , where it was used in a simple balance scale , and to move large objects in ancient Egyptian technology . The lever was also used in
7068-424: The porosity or effective porosity is used as an upper bound to the specific yield. Typically S y is orders of magnitude larger than S s . Fault zone hydrogeology is the study of how brittlely deformed rocks alter fluid flows in different lithological settings , such as clastic , igneous and carbonate rocks . Fluid movements, that can be quantified as permeability , can be facilitated or impeded due to
7192-553: The shadoof water-lifting device, the first crane machine, which appeared in Mesopotamia c. 3000 BC , and then in ancient Egyptian technology c. 2000 BC . The earliest evidence of pulleys date back to Mesopotamia in the early 2nd millennium BC, and ancient Egypt during the Twelfth Dynasty (1991–1802 BC). The screw , the last of the simple machines to be invented, first appeared in Mesopotamia during
7316-484: The thermohaline circulation of the ocean leads to a 5 °C (9 °F) warming of the northern Atlantic Ocean compared to other ocean basins. Other ocean currents redistribute heat between land and water on a more regional scale. The density and type of vegetation coverage affects solar heat absorption, water retention, and rainfall on a regional level. Alterations in the quantity of atmospheric greenhouse gases (particularly carbon dioxide and methane ) determines
7440-624: The water wheel and watermill , first appeared in the Persian Empire , in what are now Iraq and Iran, by the early 4th century BC. Kush developed the Sakia during the 4th century BC, which relied on animal power instead of human energy. Hafirs were developed as a type of reservoir in Kush to store and contain water as well as boost irrigation. Sappers were employed to build causeways during military campaigns. Kushite ancestors built speos during
7564-412: The 14th century when an engine'er (literally, one who builds or operates a siege engine ) referred to "a constructor of military engines". In this context, now obsolete, an "engine" referred to a military machine, i.e. , a mechanical contraption used in war (for example, a catapult ). Notable examples of the obsolete usage which have survived to the present day are military engineering corps, e.g. ,
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#17328527308437688-426: The 1800s included the experiments of Alessandro Volta , Michael Faraday , Georg Ohm and others and the invention of the electric telegraph in 1816 and the electric motor in 1872. The theoretical work of James Maxwell (see: Maxwell's equations ) and Heinrich Hertz in the late 19th century gave rise to the field of electronics . The later inventions of the vacuum tube and the transistor further accelerated
7812-593: The 36 licensed member institutions of the UK Engineering Council . New specialties sometimes combine with the traditional fields and form new branches – for example, Earth systems engineering and management involves a wide range of subject areas including engineering studies , environmental science , engineering ethics and philosophy of engineering . Aerospace engineering covers the design, development, manufacture and operational behaviour of aircraft , satellites and rockets . Marine engineering covers
7936-576: The 9th century. In 1206, Al-Jazari invented programmable automata / robots . He described four automaton musicians, including drummers operated by a programmable drum machine , where they could be made to play different rhythms and different drum patterns. Before the development of modern engineering, mathematics was used by artisans and craftsmen, such as millwrights , clockmakers , instrument makers and surveyors. Aside from these professions, universities were not believed to have had much practical significance to technology. A standard reference for
8060-531: The Antikythera mechanism, required sophisticated knowledge of differential gearing or epicyclic gearing , two key principles in machine theory that helped design the gear trains of the Industrial Revolution, and are widely used in fields such as robotics and automotive engineering . Ancient Chinese, Greek, Roman and Hunnic armies employed military machines and inventions such as artillery which
8184-491: The Arctic region and oceans. Climate variability is the term to describe variations in the mean state and other characteristics of climate (such as chances or possibility of extreme weather , etc.) "on all spatial and temporal scales beyond that of individual weather events." Some of the variability does not appear to be caused systematically and occurs at random times. Such variability is called random variability or noise . On
8308-478: The Bronze Age between 3700 and 3250 BC. Bloomeries and blast furnaces were also created during the 7th centuries BC in Kush. Ancient Greece developed machines in both civilian and military domains. The Antikythera mechanism , an early known mechanical analog computer , and the mechanical inventions of Archimedes , are examples of Greek mechanical engineering. Some of Archimedes' inventions, as well as
8432-456: The EU's Copernicus Climate Change Service, average global air temperature has passed 1.5C of warming the period from February 2023 to January 2024. Climate models use quantitative methods to simulate the interactions and transfer of radiative energy between the atmosphere , oceans , land surface and ice through a series of physics equations. They are used for a variety of purposes, from the study of
8556-638: The United States went to Josiah Willard Gibbs at Yale University in 1863; it was also the second PhD awarded in science in the U.S. Only a decade after the successful flights by the Wright brothers , there was extensive development of aeronautical engineering through development of military aircraft that were used in World War I . Meanwhile, research to provide fundamental background science continued by combining theoretical physics with experiments. Engineering
8680-462: The amount of solar energy retained by the planet, leading to global warming or global cooling . The variables which determine climate are numerous and the interactions complex, but there is general agreement that the broad outlines are understood, at least insofar as the determinants of historical climate change are concerned. Climate classifications are systems that categorize the world's climates. A climate classification may correlate closely with
8804-412: The aquifer exists underneath a confining bed. There are three aspects that control the nature of aquifers: stratigraphy , lithology , and geological formations and deposits. The stratigraphy relates the age and geometry of the many formations that compose the aquifer. The lithology refers to the physical components of an aquifer, such as the mineral composition and grain size. The structural features are
8928-487: The availability of fast and cheap personal computers . A quick survey of the main numerical methods used in hydrogeology, and some of the most basic principles are shown below and further discussed in the Groundwater model article. There are two broad categories of numerical methods: gridded or discretized methods and non-gridded or mesh-free methods. In the common finite difference method and finite element method (FEM)
9052-409: The aviation pioneers around the start of the 20th century although the work of Sir George Cayley has recently been dated as being from the last decade of the 18th century. Early knowledge of aeronautical engineering was largely empirical with some concepts and skills imported from other branches of engineering. The first PhD in engineering (technically, applied science and engineering ) awarded in
9176-426: The causes of climate, and empiric methods, which focus on the effects of climate. Examples of genetic classification include methods based on the relative frequency of different air mass types or locations within synoptic weather disturbances. Examples of empiric classifications include climate zones defined by plant hardiness , evapotranspiration, or more generally the Köppen climate classification which
9300-400: The chemical adsorption equilibrium has been adsorbed. This effect is particularly important for less soluble contaminants, which thus can move even hundreds or thousands times slower than water. The effect of this phenomenon is that only more soluble species can cover long distances. The retardation factor depends on the chemical nature of both the contaminant and the aquifer. Henry Darcy was
9424-473: The consequences of increasing greenhouse gases in the atmosphere, primarily carbon dioxide (see greenhouse gas ). These models predict an upward trend in the global mean surface temperature , with the most rapid increase in temperature being projected for the higher latitudes of the Northern Hemisphere. Models can range from relatively simple to quite complex. Simple radiant heat transfer models treat
9548-543: The context of environmental policy , the term "climate change" often refers only to changes in modern climate, including the rise in average surface temperature known as global warming . In some cases, the term is also used with a presumption of human causation, as in the United Nations Framework Convention on Climate Change (UNFCCC). The UNFCCC uses "climate variability" for non-human caused variations. Earth has undergone periodic climate shifts in
9672-571: The design, development, manufacture and operational behaviour of watercraft and stationary structures like oil platforms and ports . Computer engineering (CE) is a branch of engineering that integrates several fields of computer science and electronic engineering required to develop computer hardware and software . Computer engineers usually have training in electronic engineering (or electrical engineering ), software design , and hardware-software integration instead of only software engineering or electronic engineering. Geological engineering
9796-407: The development and large scale manufacturing of chemicals in new industrial plants. The role of the chemical engineer was the design of these chemical plants and processes. Aeronautical engineering deals with aircraft design process design while aerospace engineering is a more modern term that expands the reach of the discipline by including spacecraft design. Its origins can be traced back to
9920-418: The development of electronics to such an extent that electrical and electronics engineers currently outnumber their colleagues of any other engineering specialty. Chemical engineering developed in the late nineteenth century. Industrial scale manufacturing demanded new materials and new processes and by 1880 the need for large scale production of chemicals was such that a new industry was created, dedicated to
10044-402: The diffusion equation in the hydrogeology literature are: No matter which method we use to solve the groundwater flow equation , we need both initial conditions (heads at time ( t ) = 0) and boundary conditions (representing either the physical boundaries of the domain, or an approximation of the domain beyond that point). Often the initial conditions are supplied to a transient simulation, by
10168-431: The domain is completely gridded ("cut" into a grid or mesh of small elements). The analytic element method (AEM) and the boundary integral equation method (BIEM — sometimes also called BEM, or Boundary Element Method) are only discretized at boundaries or along flow elements (line sinks, area sources, etc.), the majority of the domain is mesh-free. Gridded Methods like finite difference and finite element methods solve
10292-583: The dynamics of the weather and climate system to projections of future climate. All climate models balance, or very nearly balance, incoming energy as short wave (including visible) electromagnetic radiation to the Earth with outgoing energy as long wave (infrared) electromagnetic radiation from the Earth. Any imbalance results in a change in the average temperature of the Earth. Climate models are available on different resolutions ranging from >100 km to 1 km. High resolutions in global climate models require significant computational resources, and so only
10416-402: The elements that arise due to deformations after deposition, such as fractures and folds. Understanding these aspects is paramount to understanding of how an aquifer is formed and how professionals can utilize it for groundwater engineering. Differences in hydraulic head ( h ) cause water to move from one place to another; water flows from locations of high h to locations of low h. Hydraulic head
10540-459: The existence of a fault zone . This is because different mechanism and deformed rocks can alter the porosity and hence the permeability within fault zone. Fluids involved generally are groundwater (fresh and marine waters) and hydrocarbons (Oil and Gas). As fault zone is a zone of weakness that helps to increase the weathered zone thickness and hence the help in ground water recharge. Along with faults , fractures and foliations also facilitate
10664-421: The first commercial piston steam engine in 1712, was not known to have any scientific training. The application of steam-powered cast iron blowing cylinders for providing pressurized air for blast furnaces lead to a large increase in iron production in the late 18th century. The higher furnace temperatures made possible with steam-powered blast allowed for the use of more lime in blast furnaces , which enabled
10788-409: The first half of the 19th century. These included the use of gigs to guide the machining tool over the work and fixtures to hold the work in the proper position. Machine tools and machining techniques capable of producing interchangeable parts lead to large scale factory production by the late 19th century. The United States Census of 1850 listed the occupation of "engineer" for the first time with
10912-418: The flow of water in that medium (e.g., the release of water from storage for confined aquifers is related to the storativity , while it is related to the specific yield for unconfined aquifers). An aquifer is a collection of water underneath the surface, large enough to be useful in a spring or a well. Aquifers can be unconfined, where the top of the aquifer is defined by the water table , or confined, where
11036-421: The global temperature and produce an interglacial period. Suggested causes of ice age periods include the positions of the continents , variations in the Earth's orbit, changes in the solar output, and volcanism. However, these naturally caused changes in climate occur on a much slower time scale than the present rate of change which is caused by the emission of greenhouse gases by human activities. According to
11160-419: The groundwater flow equation by breaking the problem area (domain) into many small elements (squares, rectangles, triangles, blocks, tetrahedra , etc.) and solving the flow equation for each element (all material properties are assumed constant or possibly linearly variable within an element), then linking together all the elements using conservation of mass across the boundaries between the elements (similar to
11284-433: The groundwater mainly in hard rock terrains. Often we are interested in how the moving groundwater will transport dissolved contaminants around (the sub-field of contaminant hydrogeology). The contaminants which are man-made (e.g., petroleum products , nitrate , chromium or radionuclides ) or naturally occurring (e.g., arsenic , salinity ), can be transported through three main mechanisms, advection (transport along
11408-478: The interplay of the different facets of a multi-component system often requires knowledge in several 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 (typically less than 450 meters below
11532-514: The invention of Portland cement . Applied science led to the development of the steam engine. The sequence of events began with the invention of the barometer and the measurement of atmospheric pressure by Evangelista Torricelli in 1643, demonstration of the force of atmospheric pressure by Otto von Guericke using the Magdeburg hemispheres in 1656, laboratory experiments by Denis Papin , who built experimental model steam engines and demonstrated
11656-433: The land surface). The very shallow flow of water in the subsurface (the upper 3 m) is pertinent to the fields of soil science , agriculture , and civil engineering , as well as to hydrogeology. The general flow of fluids (water, hydrocarbons , geothermal fluids, etc.) in deeper formations is also a concern of geologists, geophysicists , and petroleum geologists . Groundwater is a slow-moving, viscous fluid (with
11780-527: The limits within which a viable object or system may be produced and operated. Climate This is an accepted version of this page Climate is the long-term weather pattern in a region, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorological variables that are commonly measured are temperature , humidity , atmospheric pressure , wind , and precipitation . In
11904-562: The main direction of flow at seepage velocity), diffusion (migration of the contaminant from high to low concentration areas), and hydrodynamic dispersion (due to microscale heterogeneities present in the porous medium and non-uniform velocity distribution relative to seepage velocity). Besides needing to understand where the groundwater is flowing, based on the other hydrologic properties discussed above, there are additional aquifer properties which affect how dissolved contaminants move with groundwater. Hydrodynamic dispersivity (α L , α T )
12028-456: The modern time scale, their observation frequency, their known error, their immediate environment, and their exposure have changed over the years, which must be considered when studying the climate of centuries past. Long-term modern climate records skew towards population centres and affluent countries. Since the 1960s, the launch of satellites allow records to be gathered on a global scale, including areas with little to no human presence, such as
12152-404: The most common atmospheric variables (air temperature, pressure, precipitation and wind), other variables such as humidity, visibility, cloud amount, solar radiation, soil temperature, pan evaporation rate, days with thunder and days with hail are also collected to measure change in climate conditions. The difference between climate and weather is usefully summarized by the popular phrase "Climate
12276-745: The origin of air masses that define the climate of a region. Paleoclimatology is the study of ancient climates. Paleoclimatologists seek to explain climate variations for all parts of the Earth during any given geologic period, beginning with the time of the Earth's formation. Since very few direct observations of climate were available before the 19th century, paleoclimates are inferred from proxy variables . They include non-biotic evidence—such as sediments found in lake beds and ice cores —and biotic evidence—such as tree rings and coral. Climate models are mathematical models of past, present, and future climates. Climate change may occur over long and short timescales due to various factors. Recent warming
12400-705: The other hand, periodic variability occurs relatively regularly and in distinct modes of variability or climate patterns. There are close correlations between Earth's climate oscillations and astronomical factors ( barycenter changes, solar variation , cosmic ray flux, cloud albedo feedback , Milankovic cycles ), and modes of heat distribution between the ocean-atmosphere climate system. In some cases, current, historical and paleoclimatological natural oscillations may be masked by significant volcanic eruptions , impact events , irregularities in climate proxy data, positive feedback processes or anthropogenic emissions of substances such as greenhouse gases . Over
12524-402: The past state of the climate. It demonstrates periods of stability and periods of change and can indicate whether changes follow patterns such as regular cycles. Details of the modern climate record are known through the taking of measurements from such weather instruments as thermometers , barometers , and anemometers during the past few centuries. The instruments used to study weather over
12648-462: The past, including four major ice ages . These consist of glacial periods where conditions are colder than normal, separated by interglacial periods. The accumulation of snow and ice during a glacial period increases the surface albedo , reflecting more of the Sun's energy into space and maintaining a lower atmospheric temperature. Increases in greenhouse gases , such as by volcanic activity , can increase
12772-508: The poles in latitude in response to shifting climate zones." Climate (from Ancient Greek κλίμα 'inclination') is commonly defined as the weather averaged over a long period. The standard averaging period is 30 years, but other periods may be used depending on the purpose. Climate also includes statistics other than the average, such as the magnitudes of day-to-day or year-to-year variations. The Intergovernmental Panel on Climate Change (IPCC) 2001 glossary definition
12896-408: The porosity available to flow (sometimes called effective porosity ). Permeability is an expression of the connectedness of the pores. For instance, an unfractured rock unit may have a high porosity (it has many holes between its constituent grains), but a low permeability (none of the pores are connected). An example of this phenomenon is pumice , which, when in its unfractured state, can make
13020-474: The power to weight ratio of steam engines made practical steamboats and locomotives possible. New steel making processes, such as the Bessemer process and the open hearth furnace, ushered in an area of heavy engineering in the late 19th century. One of the most famous engineers of the mid-19th century was Isambard Kingdom Brunel , who built railroads, dockyards and steamships. The Industrial Revolution created
13144-403: The properties of aquifers. Meinzer also highlighted the importance of studying the geochemistry of water, as well as the impact of high salinity levels in aquifers. Darcy's law is a constitutive equation , empirically derived by Henry Darcy in 1856, which states that the amount of groundwater discharging through a given portion of aquifer is proportional to the cross-sectional area of flow,
13268-421: The public. Twenty-nine states require professional licensing for geologists to offer their services to the public, which often includes work within the domains of developing, managing, and/or remediating groundwater resources. For example: aquifer drawdown or overdrafting and the pumping of fossil water may be a contributing factor to sea-level rise. One of the main tasks a hydrogeologist typically performs
13392-434: The rise of engineering as a profession in the 18th century, the term became more narrowly applied to fields in which mathematics and science were applied to these ends. Similarly, in addition to military and civil engineering, the fields then known as the mechanic arts became incorporated into engineering. Canal building was an important engineering work during the early phases of the Industrial Revolution. John Smeaton
13516-426: The same with full cognizance of their design; or to forecast their behavior under specific operating conditions; all as respects an intended function, economics of operation and safety to life and property. Engineering has existed since ancient times, when humans devised inventions such as the wedge, lever, wheel and pulley, etc. The term engineering is derived from the word engineer , which itself dates back to
13640-464: The state of mechanical arts during the Renaissance is given in the mining engineering treatise De re metallica (1556), which also contains sections on geology, mining, and chemistry. De re metallica was the standard chemistry reference for the next 180 years. The science of classical mechanics , sometimes called Newtonian mechanics, formed the scientific basis of much of modern engineering. With
13764-432: The structure of mathematics to arrive at a simple, elegant solution, but the required derivation for all but the simplest domain geometries can be quite complex (involving non-standard coordinates , conformal mapping , etc.). Analytic solutions typically are also simply an equation that can give a quick answer based on a few basic parameters. The Theis equation is a very simple (yet still very useful) analytic solution to
13888-486: The thirty-year period from 1901 to 1930 as the reference time frame for climatological standard normals. In 1982, the WMO agreed to update climate normals, and these were subsequently completed on the basis of climate data from 1 January 1961 to 31 December 1990. The 1961–1990 climate normals serve as the baseline reference period. The next set of climate normals to be published by WMO is from 1991 to 2010. Aside from collecting from
14012-425: The transient evolution of head due to the effects of pumping one or a number of pumping wells. The Thiem equation is a solution to the steady state groundwater flow equation (Laplace's Equation) for flow to a well. Unless there are large sources of water nearby (a river or lake), true steady-state is rarely achieved in reality. Both above equations are used in aquifer tests (pump tests). The Hooghoudt equation
14136-414: The transition from charcoal to coke . These innovations lowered the cost of iron, making horse railways and iron bridges practical. The puddling process , patented by Henry Cort in 1784 produced large scale quantities of wrought iron. Hot blast , patented by James Beaumont Neilson in 1828, greatly lowered the amount of fuel needed to smelt iron. With the development of the high pressure steam engine,
14260-440: The unsaturated groundwater flow equation. Hydraulic conductivity ( K ) is a measure of permeability that is a property of both the fluid and the porous medium (i.e. the hydraulic conductivity of water and of oil will not be the same even if in the same geologic formation). Transmissivity is the product of hydraulic conductivity and the aquifer thickness (typically used as an indication of the ability of an aquifer to deliver water to
14384-576: The use of a piston, which he published in 1707. Edward Somerset, 2nd Marquess of Worcester published a book of 100 inventions containing a method for raising waters similar to a coffee percolator . Samuel Morland , a mathematician and inventor who worked on pumps, left notes at the Vauxhall Ordinance Office on a steam pump design that Thomas Savery read. In 1698 Savery built a steam pump called "The Miner's Friend". It employed both vacuum and pressure. Iron merchant Thomas Newcomen , who built
14508-475: The variability or average state of the atmosphere over time scales ranging from decades to millions of years. These changes can be caused by processes internal to the Earth , external forces (e.g. variations in sunlight intensity) or human activities, as found recently. Scientists have identified Earth's Energy Imbalance (EEI) to be a fundamental metric of the status of global change. In recent usage, especially in
14632-448: The years, the definitions of climate variability and the related term climate change have shifted. While the term climate change now implies change that is both long-term and of human causation, in the 1960s the word climate change was used for what we now describe as climate variability, that is, climatic inconsistencies and anomalies. Climate change is the variation in global or regional climates over time. It reflects changes in
14756-623: Was a steam jack driven by a steam turbine , described in 1551 by Taqi al-Din Muhammad ibn Ma'ruf in Ottoman Egypt . The cotton gin was invented in India by the 6th century AD, and the spinning wheel was invented in the Islamic world by the early 11th century, both of which were fundamental to the growth of the cotton industry . The spinning wheel was also a precursor to the spinning jenny , which
14880-513: Was a key development during the early Industrial Revolution in the 18th century. The earliest programmable machines were developed in the Muslim world. A music sequencer , a programmable musical instrument , was the earliest type of programmable machine. The first music sequencer was an automated flute player invented by the Banu Musa brothers, described in their Book of Ingenious Devices , in
15004-407: Was an American scientist who is often called the "father of modern groundwater hydrology". He standardized key terms in the field as well as determined principles regarding occurrence, movement, and discharge. He proved that the flow of water obeys Darcy's law. He also proposed the use of geophysical methods and recorders on wells, as well as suggested pumping tests to gather quantitative information on
15128-642: Was developed by the Greeks around the 4th century BC, the trireme , the ballista and the catapult . In the Middle Ages, the trebuchet was developed. The earliest practical wind-powered machines, the windmill and wind pump , first appeared in the Muslim world during the Islamic Golden Age , in what are now Iran, Afghanistan, and Pakistan, by the 9th century AD. The earliest practical steam-powered machine
15252-533: Was originally designed to identify the climates associated with certain biomes . A common shortcoming of these classification schemes is that they produce distinct boundaries between the zones they define, rather than the gradual transition of climate properties more common in nature. Paleoclimatology is the study of past climate over a great period of the Earth 's history. It uses evidence with different time scales (from decades to millennia) from ice sheets, tree rings, sediments, pollen, coral, and rocks to determine
15376-505: Was the first self-proclaimed civil engineer and is often regarded as the "father" of civil engineering. He was an English civil engineer responsible for the design of bridges, canals, harbors, and lighthouses. He was also a capable mechanical engineer and an eminent physicist . Using a model water wheel, Smeaton conducted experiments for seven years, determining ways to increase efficiency. Smeaton introduced iron axles and gears to water wheels. Smeaton also made mechanical improvements to
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