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72-630: The Vinalopó is a small river flowing through the Alicante province , of Spain. It flows from north to south and, with a length of 81 km., it is the longest of the rivers which flows for its entire length within the limits of this province. It discharges into the Mediterranean at Salinas de Santa Pola. For some historians, it corresponds to the Alebus incidentally mentioned by Avienius in his Ora Maritima . Three comarcas (districts) in

144-454: A "river", it is actually more a stream, especially south of Beneixama , not far from its source. In that location, historical farming rights allow the farmers to take most of its flow for agricultural purposes. Past this location, it turns more into a tiny channel draining the residual waters of the various cities it passes through. Thus, south of Beneixama, its flow is depleted, saline, and polluted. The upper Vinalopó has two small tributaries,

216-588: A brief Carthaginian period, the Romans took over. Romanization in this part of Iberia was intense, the Via Augusta communicated this part of the Empire to the metropoli and so several cities thrived, from which the one known as Ilici Augusta (now Elche) even reached the status of colonia . After a brief period of Visigothic ruling, the area was taken by Islamic armies and became a part of Al Andalus . From

288-630: A confining layer, often made up of clay. The confining layer might offer some protection from surface contamination. If the distinction between confined and unconfined is not clear geologically (i.e., if it is not known if a clear confining layer exists, or if the geology is more complex, e.g., a fractured bedrock aquifer), the value of storativity returned from an aquifer test can be used to determine it (although aquifer tests in unconfined aquifers should be interpreted differently than confined ones). Confined aquifers have very low storativity values (much less than 0.01, and as little as 10 ), which means that

360-559: A low ebb due to harsh competition from fast pace growing economies in Asia. The traditionally important toys industry around the Ibi and Onil area is another one competing internationally with those same areas. A sector which has gained preeminence during the last 20 years is marble quarrying and processing, it happens mostly in the Novelda and Pinós area. Still, what the province is known for

432-403: 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 land areas that were not submerged until the ice age ended 20,000 years ago. The volume is estimated to be 100 times the amount of water extracted from other aquifers since 1900. An aquitard

504-476: A number of protected wildlife areas. There are three Natural Parks: Serra de Mariola which is important for the conservation of its flora, Salines de Santa Pola and El Fondo both important areas for migratory birds. Other areas of interest include Salines Lagoon, Serra de Salina, Elda Reservoir and Elx/Elche Reservoir. 38°43′12″N 0°37′34″W  /  38.720°N 0.626°W  / 38.720; -0.626 Province of Alicante Alicante

576-507: A periodicity that has been estimated as approximately once every 9 years or so) brief episodes of torrential rain (predominantly during the Autumn months, especially October and November). Following one of these episodes, all the dry riverbeds fill with water and discharge into the Vinalopó. This means that for the few days it takes until all this water is drained from the surrounding land,

648-442: A rock unit of low porosity is highly fractured, it can also make a good aquifer (via fissure flow), provided the rock has a hydraulic conductivity sufficient to facilitate movement of water. Challenges for using groundwater include: overdrafting (extracting groundwater beyond the equilibrium yield of the aquifer), groundwater-related subsidence of land, groundwater becoming saline, groundwater pollution . Aquifer depletion

720-440: A two-dimensional slice of the aquifer) appear to be layers of alternating coarse and fine materials. Coarse materials, because of the high energy needed to move them, tend to be found nearer the source (mountain fronts or rivers), whereas the fine-grained material will make it farther from the source (to the flatter parts of the basin or overbank areas—sometimes called the pressure area). Since there are less fine-grained deposits near

792-416: A well in a fracture trace or intersection of fracture traces increases the likelihood to encounter good water production. Voids in karst aquifers can be large enough to cause destructive collapse or subsidence of the ground surface that can initiate a catastrophic release of contaminants. Groundwater flow rate in karst aquifers is much more rapid than in porous aquifers as shown in the accompanying image to

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864-587: Is a problem in some areas, especially in northern Africa , where one example is the Great Manmade River project of Libya . However, new methods of groundwater management such as artificial recharge and injection of surface waters during seasonal wet periods has extended the life of many freshwater aquifers, especially in the United States. The Great Artesian Basin situated in Australia

936-554: 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 either clay or non-porous rock with low hydraulic conductivity . Groundwater can be found at nearly every point in the Earth's shallow subsurface to some degree, although aquifers do not necessarily contain fresh water . The Earth's crust can be divided into two regions:

1008-1019: Is arguably the largest groundwater aquifer in the world (over 1.7 million km or 0.66 million sq mi). It plays a large part in water supplies for Queensland, and some remote parts of South Australia. Discontinuous sand bodies at the base of the McMurray Formation in the Athabasca Oil Sands region of northeastern Alberta , Canada, are commonly referred to as the Basal Water Sand (BWS) aquifers . Saturated with water, they are confined beneath impermeable bitumen -saturated sands that are exploited to recover bitumen for synthetic crude oil production. Where they are deep-lying and recharge occurs from underlying Devonian formations they are saline, and where they are shallow and recharged by surface water they are non-saline. The BWS typically pose problems for

1080-649: Is bordered by the provinces of Murcia on the southwest, Albacete on the west, Valencia on the north, and the Mediterranean Sea on the east. The province is named after its capital, the city of Alicante (also known in Valencian as Alacant ). According to the 2018 population data, Alicante ranks as the fourth most populous province in Spain (after Madrid , Barcelona and Valencia ), with 1,838,819 inhabitants. Cities with more than 50,000 inhabitants in

1152-579: Is called hydrogeology . Related terms include aquitard , which is a bed of low permeability along an aquifer, and aquiclude (or aquifuge ), which is a solid, impermeable area underlying or overlying an aquifer, the pressure of which could lead to the formation of a confined aquifer. The classification of aquifers is as follows: Saturated versus unsaturated; aquifers versus aquitards; confined versus unconfined; isotropic versus anisotropic; porous, karst, or fractured; transboundary aquifer. Groundwater from aquifers can be sustainably harvested by humans through

1224-501: Is considered to be a high rate for porous aquifers, as illustrated by the water slowly seeping from sandstone in the accompanying image to the left. Porosity is important, but, alone , it does not determine a rock's ability to act as an aquifer. Areas of the Deccan Traps (a basaltic lava) in west central India are good examples of rock formations with high porosity but low permeability, which makes them poor aquifers. Similarly,

1296-460: Is divided into nine comarcas or comarques (in Valencian ): Alcoy: Alicante: Aquifer An aquifer is an underground layer of water -bearing material, consisting of permeable or fractured rock, or of unconsolidated materials ( gravel , sand , or silt ). Aquifers vary greatly in their characteristics. The study of water flow in aquifers and the characterization of aquifers

1368-421: Is held in place by surface adhesive forces and it rises above the water table (the zero- gauge-pressure isobar ) by capillary action to saturate a small zone above the phreatic surface (the capillary fringe ) at less than atmospheric pressure. This is termed tension saturation and is not the same as saturation on a water-content basis. Water content in a capillary fringe decreases with increasing distance from

1440-596: Is its massive tourism sector . The Costa Blanca 's generally mild and sunny weather attracts millions of tourists from other European countries such as the Netherlands, the UK and Ireland, Germany, Belgium, Norway or France and also from other parts in Spain like Madrid. Thousands of families from other places own a second home in the Alicante province which they use for their vacation time. Traditionally, Alicante province

1512-524: Is mostly flat to the south, in the Vega Baja del Segura area; the most elevated points in the province are Aitana (1,558 m), Puig Campana (1,410 m), Montcabrer (1,389 m), Carrascar de la Font Roja (1,354 m), Maigmó (1,296 m), Serra de Crevillent (835 m) and El Montgó (753 m). All of these peaks are a part of the Subbaetic Range . The coast extends from the cape, Cap de la Nau , in

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1584-419: Is the level to which water will rise in a large-diameter pipe (e.g., a well) that goes down into the aquifer and is open to the atmosphere. Aquifers are typically saturated regions of the subsurface that produce an economically feasible quantity of water to a well or spring (e.g., sand and gravel or fractured bedrock often make good aquifer materials). An aquitard is a zone within the Earth that restricts

1656-427: The saturated zone or phreatic zone (e.g., aquifers, aquitards, etc.), where all available spaces are filled with water, and the unsaturated zone (also called the vadose zone ), where there are still pockets of air that contain some water, but can be filled with more water. Saturated means the pressure head of the water is greater than atmospheric pressure (it has a gauge pressure > 0). The definition of

1728-834: The Atlas Mountains in North Africa, the Lebanon and Anti-Lebanon ranges between Syria and Lebanon, the Jebel Akhdar in Oman, parts of the Sierra Nevada and neighboring ranges in the United States' Southwest , have shallow aquifers that are exploited for their water. Overexploitation can lead to the exceeding of the practical sustained yield; i.e., more water is taken out than can be replenished. Along

1800-615: The Guarani people , it covers 1,200,000 km (460,000 sq mi), with a volume of about 40,000 km (9,600 cu mi), a thickness of between 50 and 800 m (160 and 2,620 ft) and a maximum depth of about 1,800 m (5,900 ft). The Ogallala Aquifer of the central United States is one of the world's great aquifers, but in places it is being rapidly depleted by growing municipal use, and continuing agricultural use. This huge aquifer, which underlies portions of eight states, contains primarily fossil water from

1872-604: The Marchal (a short stream near Banyeres de Mariola ) and the Tarafa (another short stream, which flows through Aspe ), but both of these may completely dry out during the Summer. Perhaps more important than these tributaries are the various ramblas or dry riverbeds which discharge into the Vinalopó following extensive periods of rain. This is because, despite being a very dry area, Alicante province periodically suffers (within

1944-661: The depositional sedimentary environment and later natural cementation of the sand grains. The environment where a sand body was deposited controls the orientation of the sand grains, the horizontal and vertical variations, and the distribution of shale layers. Even thin shale layers are important barriers to groundwater flow. All these factors affect the porosity and permeability of sandy aquifers. Sandy deposits formed in shallow marine environments and in windblown sand dune environments have moderate to high permeability while sandy deposits formed in river environments have low to moderate permeability. Rainfall and snowmelt enter

2016-535: The semi-arid climate which characterizes the area that the river flows through (see Geography of the Comunitat Valenciana ), the hydrological cycle in the Vinalopo's watershed is extremely fragile. Hence, were it not for sustained agricultural use over the centuries -not only of water extracted from the river but, probably more importantly, from the aquifers related to it- it could be argued that

2088-625: The 13th century, kings like Ferdinand III of Castile , James I of Aragon , Alfonso X of Castile , James II of Aragon reconquered the cities that Moors occupied. What today is the Alicante province was initially split between the Crown of Castile and the Crown of Aragon by means of the Treaty of Almizra , however later on the whole territory became under the control of the Kingdom of Valencia , which

2160-485: The 50 provinces of Spain, Alicante is the only one with three metropolitan areas —Alicante–Elche, Elda–Petrer and Benidorm—even though only one of them (Alicante–Elche) is ranked within the Spanish top ten metropolitan areas. It has an area of 5,816.5 km (2,245.8 sq mi), and so it has a population density of 313.8 inhabitants/km . The province is mountainous, especially in the north and midwest, whereas it

2232-442: The Alicante province are named after it: Alt Vinalopó , Vinalopó Mitjà and Baix Vinalopó which mean, respectively, Upper Vinalopó, Middle Vinalopó and Lower Vinalopó. Its source lies in a mountainous part of the northwest part of the Alicante province, between Bocairent and Banyeres de Mariola in an area known as Els Bruchs . It does not currently discharge into the Mediterranean Sea , but due to its diminished flow in

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2304-542: The International Trade Fair for Footwear and Associated Industries has been held in these cities for many years. Shoemaking is also an important industry in other cities such as Petrer, Monòver and Villena. Viticulture is another important sector in this region, particularly in the Middle Vinalopó, where it is possible to define two different areas, the north and the south. The grapes grown in

2376-669: The United States accelerated in the late 1940s and continued at an almost steady linear rate through the end of the century. In addition to widely recognized environmental consequences, groundwater depletion also adversely impacts the long-term sustainability of groundwater supplies to help meet the Nation’s water needs." An example of a significant and sustainable carbonate aquifer is the Edwards Aquifer in central Texas . This carbonate aquifer has historically been providing high quality water for nearly 2 million people, and even today,

2448-481: The Vinalopó has been the location of many settlements throughout history, as shown by the important Iberian – Roman villages of Idella (Elda) o Illici (Elx/Elche). During the second half of the 20th century the valley became a dynamic urban and industrial axis with industrial activity mainly concentrated in the footwear and leather goods industries. The majority of Spanish footwear is produced in Elda and Elche and

2520-406: The Vinalopó would be a more substantial river. But at the present time, after centuries of usage, and given the restricted precipitation in the area, its fragile hydrological cycle was definitely broken a long time ago and it is now impossible that the aquifers could replenish within a lifetime, even if exploitation ceased completely. Due to this over extraction and the droughts that the zone suffers

2592-421: The aquifer is storing water using the mechanisms of aquifer matrix expansion and the compressibility of water, which typically are both quite small quantities. Unconfined aquifers have storativities (typically called specific yield ) greater than 0.01 (1% of bulk volume); they release water from storage by the mechanism of actually draining the pores of the aquifer, releasing relatively large amounts of water (up to

2664-579: The area around Novelda, fishing from the port of Santa Pola and tourism again in Santa Pola and centered on urbanizations near to Elx/Elche (Arenales del Sol, El Altet, La Marina, etc.) The number of people living in the three comarcas (districts) is around 500,000. The biggest city is Elx/Elche with a population of 230,000, followed by the conurbation of Elda-Petrer-Monòver with 100,000 then Novelda-Aspe with 50,000, Villena has 35,000 inhabitants and Santa Pola has more than 30,000. The Vinalopó also has

2736-601: The centuries enhanced by erosion , which the scarcely vegetated matorral areas through which the river passes have suffered over time. Legend has it that Amílcar Barca , the father of Hannibal , drowned while trying to cross the Vinalopó as he was fleeing the Iberians following one of the many battles between the Carthaginians and the inhabitants of this area of the Iberian Peninsula . The valley of

2808-469: The coast such El Fondo and the former wetlands and now salt evaporation ponds in Santa Pola and Torrevieja. All of them are key Ramsar Sites which make the Alicante province of high relevance for both migratory and resident seabirds and waterbirds. Important coastal dunes are present in the Guardamar area which were planted with thousands of pine trees during the 19th century in order to protect

2880-409: The coastlines of certain countries, such as Libya and Israel, increased water usage associated with population growth has caused a lowering of the water table and the subsequent contamination of the groundwater with saltwater from the sea. In 2013 large freshwater aquifers were discovered under continental shelves off Australia, China, North America and South Africa. They contain an estimated half

2952-487: The complexity of karst aquifers. These conventional investigation methods need to be supplemented with dye traces , measurement of spring discharges, and analysis of water chemistry. U.S. Geological Survey dye tracing has determined that conventional groundwater models that assume a uniform distribution of porosity are not applicable for karst aquifers. Linear alignment of surface features such as straight stream segments and sinkholes develop along fracture traces . Locating

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3024-526: The compound Kh and Kv values are different (see hydraulic transmissivity and hydraulic resistance ). When calculating flow to drains or flow to wells in an aquifer, the anisotropy is to be taken into account lest the resulting design of the drainage system may be faulty. To properly manage an aquifer its properties must be understood. Many properties must be known to predict how an aquifer will respond to rainfall, drought, pumping, and contamination . Considerations include where and how much water enters

3096-439: The drainable porosity of the aquifer material, or the minimum volumetric water content ). In isotropic aquifers or aquifer layers the hydraulic conductivity (K) is equal for flow in all directions, while in anisotropic conditions it differs, notably in horizontal (Kh) and vertical (Kv) sense. Semi-confined aquifers with one or more aquitards work as an anisotropic system, even when the separate layers are isotropic, because

3168-557: The fissures. The enlarged fissures allow a larger quantity of water to enter which leads to a progressive enlargement of openings. Abundant small openings store a large quantity of water. The larger openings form a conduit system that drains the aquifer to springs. Characterization of karst aquifers requires field exploration to locate sinkholes, swallets , sinking streams , and springs in addition to studying geologic maps . Conventional hydrogeologic methods such as aquifer tests and potentiometric mapping are insufficient to characterize

3240-478: The flow of groundwater from one aquifer to another. A completely impermeable aquitard is called an aquiclude or aquifuge . Aquitards contain layers of either clay or non-porous rock with low hydraulic conductivity . In mountainous areas (or near rivers in mountainous areas), the main aquifers are typically unconsolidated alluvium , composed of mostly horizontal layers of materials deposited by water processes (rivers and streams), which in cross-section (looking at

3312-549: The flow rate of the river approaches what it may have been in the very distant past. There are a number of important ramblas in the vicinity of Elda - Petrer such as the Pusa, Melva, Sapo and Bateig. Another tributary is the Acequia del Rey which discharges into the Vinalopó near Santa Eulalia. The waters of this river are briny and they drain the watershed around Villena . During normal conditions (torrential rain episodes aside),

3384-526: The groundwater from rainfall and snowmelt, how fast and in what direction the groundwater travels, and how much water leaves the ground as springs. Computer models can be used to test how accurately the understanding of the aquifer properties matches the actual aquifer performance. Environmental regulations require sites with potential sources of contamination to demonstrate that the hydrology has been characterized . Porous aquifers typically occur in sand and sandstone . Porous aquifer properties depend on

3456-610: The groundwater where the aquifer is near the surface. Groundwater flow directions can be determined from potentiometric surface maps of water levels in wells and springs. Aquifer tests and well tests can be used with Darcy's law flow equations to determine the ability of a porous aquifer to convey water. Analyzing this type of information over an area gives an indication how much water can be pumped without overdrafting and how contamination will travel. In porous aquifers groundwater flows as slow seepage in pores between sand grains. A groundwater flow rate of 1 foot per day (0.3 m/d)

3528-596: The inner part of the province (Monforte, Novelda, Pinós), also near the coast in the Marina Alta area. Fishing is important all along the coast, with important fishing harbours such as Santa Pola, Calp or Dénia. Industry has been historically important in the textile sector around Alcoy. Footwear still remains as the flagship industrial sector of the province, which occurs in Elche, Elda, Petrer and Villena, both labour-intensive footwear and, specially, textile are at

3600-491: The left. For example, in the Barton Springs Edwards aquifer, dye traces measured the karst groundwater flow rates from 0.5 to 7 miles per day (0.8 to 11.3 km/d). The rapid groundwater flow rates make karst aquifers much more sensitive to groundwater contamination than porous aquifers. In the extreme case, groundwater may exist in underground rivers (e.g., caves underlying karst topography . If

3672-401: The local author al-Idrîs does not even name it and he just mentions "a brackish stream near Elche whose waters are not good for drinking". Nevertheless, the Vinalopó has shaped what is, in places, a quite significant riverbed compared to its currently meager flow. This is particularly so in the stretch from Aspe to below Elche. This may be partially explained by repeated flooding episodes over

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3744-527: The longest inscriptions remaining in the undeciphered Iberian language were found there. Along the coast and contemporarily to the Iberians, the seafaring Phoenicians (in Guardamar) and Greeks (along the coastal section to the north of the Alicante city) settled stable trading colonies and interacted with the former (see Lady of Elche for the most renowned archeological piece of this period). After

3816-630: The lower part of its course, it fades out into a series of small irrigation channels ( séquies ) which flow south of Elx/Elche into the marshes known as El Fondo Natural Park and the Salines de Santa Pola Natural Park. The river, despite having been tiny during historical times, represents a significant corridor through the generally mountainous terrain surrounding it, along which several cities were settled, namely, from north to south, Banyeres de Mariola , Villena , Sax , Elda , Petrer , Novelda and Elx/Elche . Despite officially being called

3888-533: The maximum sustained flow of the Vinalopó is reached by early winter in Colonia Santa Eulalia (near Sax ) with an average of just 0,85 m³/s. By the time it reaches Aspe its average flow has reduced to a mere 0,38 m³/s. However, during periods of peak flow the river has breached its banks resulting in flooding that has caused damage to humans and property in Elda, this has occurred on a number of occasions most notable in 1906 and 1982. Due to

3960-462: The micro-porous (Upper Cretaceous ) Chalk Group of south east England, although having a reasonably high porosity, has a low grain-to-grain permeability, with its good water-yielding characteristics mostly due to micro-fracturing and fissuring. Karst aquifers typically develop in limestone . Surface water containing natural carbonic acid moves down into small fissures in limestone. This carbonic acid gradually dissolves limestone thereby enlarging

4032-597: The north to almost reaching the Mar Menor (Minor Sea) in the south. With regard to water sources, due to the dry rain regime there are no major rivers, but mostly ramblas (dry rivers), which fill in with water when torrential rains occur. The only remarkable streams are the Vinalopó , Serpis , and the river Segura . Other minor seasonal creeks (some completely dried out in summer) are Girona , Algar , Amadorio and Ebo . There are saline wetlands and marshlands along

4104-468: The northern area (around Monòver , El Pinós and Villena ) are used to make wine while those grown in the southern area (centered on Novelda, Aspe and Monforte del Cid) are destined for the table. Grapes grown in the southern area are protected under the designation of origin Vinalopó Grape . Other commercially important activities include the production of cut stone and marble particularly in

4176-416: The phreatic surface. The capillary head depends on soil pore size. In sandy soils with larger pores, the head will be less than in clay soils with very small pores. The normal capillary rise in a clayey soil is less than 1.8 m (6 ft) but can range between 0.3 and 10 m (1 and 33 ft). The capillary rise of water in a small- diameter tube involves the same physical process. The water table

4248-461: The province are Alicante (334,757 inhabitants), Elche (230,112), Torrevieja (101,792), Orihuela (86,164), Benidorm (71,034), Alcoy (61,552), Elda (55,168), and San Vicente del Raspeig (53,126). The province has the largest ratio of foreigner population among all Spanish provinces. The total of 446,368 foreigners are registered in the province, which represents 23.6 percent of the total population. Out of 141 municipalities that make up

4320-513: The province, foreign population is above 25% in 54 municipalities, and above 50% in 19 municipalities. The latter include San Fulgencio (80%), Rojales (74%), Benitatxell (69.8%), Algorfa (69.7%), Llíber (67%), Teulada (65.5%), Daya Vieja (64.4%); San Miguel de Salinas (64.3%), Calp (62.8%), Els Poblets (61.6%), Alcalalí (60.8%), Benijófar (58.5%), L'Alfàs del Pi (56.6%), Orba (55%), Xàbia (54%), Torrevieja (53.5%), Murla (52%), Fondó (51.7%), and Benidoleig (50%). From

4392-402: The recovery of bitumen, whether by open-pit mining or by in situ methods such as steam-assisted gravity drainage (SAGD), and in some areas they are targets for waste-water injection. The Guarani Aquifer , located beneath the surface of Argentina , Brazil , Paraguay , and Uruguay , is one of the world's largest aquifer systems and is an important source of fresh water . Named after

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4464-458: The river along its final stretch through the illegal fields around Santa Pola in order that the river discharges into the sea at its former location. However, due to the particularly dry conditions of the areas it goes through, the Vinalopó may never have been particularly deep or wide, at least not during historical times. Thus, for example, in the 12th century, during the Al-Andalus period,

4536-485: The river bed nearest to the point where it historically discharged into the sea Salines de Santa Pola is left with no flow during certain periods. However, following inundations the river recovers is former flow causing floods in the fields to the south of Elche and in an area of salt flats. This has motivated the Hydrographic Confederation of Júcar to carry out works to recover the former course of

4608-429: The same geologic unit may be confined in one area and unconfined in another. Unconfined aquifers are sometimes also called water table or phreatic aquifers, because their upper boundary is the water table or phreatic surface (see Biscayne Aquifer ). Typically (but not always) the shallowest aquifer at a given location is unconfined, meaning it does not have a confining layer (an aquitard or aquiclude) between it and

4680-425: The source, this is a place where aquifers are often unconfined (sometimes called the forebay area), or in hydraulic communication with the land surface. An unconfined aquifer has no impermeable barrier immediately above it, such that the water level can rise in response to recharge. A confined aquifer has an overlying impermeable barrier that prevents the water level in the aquifer from rising any higher. An aquifer in

4752-419: The surface are not only more likely to be used for water supply and irrigation, but are also more likely to be replenished by local rainfall. Although aquifers are sometimes characterized as "underground rivers or lakes," they are actually porous rock saturated with water. Many desert areas have limestone hills or mountains within them or close to them that can be exploited as groundwater resources. Part of

4824-420: The surface. The term "perched" refers to ground water accumulating above a low-permeability unit or strata, such as a clay layer. This term is generally used to refer to a small local area of ground water that occurs at an elevation higher than a regionally extensive aquifer. The difference between perched and unconfined aquifers is their size (perched is smaller). Confined aquifers are aquifers that are overlain by

4896-618: The time of the last glaciation . Annual recharge, in the more arid parts of the aquifer, is estimated to total only about 10 percent of annual withdrawals. According to a 2013 report by the United States Geological Survey (USGS), the depletion between 2001 and 2008, inclusive, is about 32 percent of the cumulative depletion during the entire 20th century. In the United States, the biggest users of water from aquifers include agricultural irrigation and oil and coal extraction. "Cumulative total groundwater depletion in

4968-443: The use of qanats leading to a well. This groundwater is a major source of fresh water for many regions, however can present a number of challenges such as overdrafting (extracting groundwater beyond the equilibrium yield of the aquifer), groundwater-related subsidence of land, and the salinization or pollution of the groundwater. Aquifers occur from near-surface to deeper than 9,000 metres (30,000 ft). Those closer to

5040-476: The ville from the dunes advancing, which has created now an area of remarkable ecologic value. The climate is strikingly diverse for such a reduced area. Three major areas can be cited: The Iberians were the oldest documented people living in what today is the Alicante province. Belonging to these there are several archaeologic sites from which is especially known the one in La Serreta (near Alcoy) because

5112-410: The water table is the surface where the pressure head is equal to atmospheric pressure (where gauge pressure = 0). Unsaturated conditions occur above the water table where the pressure head is negative (absolute pressure can never be negative, but gauge pressure can) and the water that incompletely fills the pores of the aquifer material is under suction . The water content in the unsaturated zone

5184-619: Was a component Kingdom of the Crown of Aragon. Alicante contributes with 12 deputies in the Spanish Parliament and with 36 deputies in the Corts Valencianes , the regional Parliament of the Valencian Community . The main industries in Alicante province are, in the primary sector, intensive agriculture , especially in the fertile Vega Baja del Segura, Camp d'Elx (Elche's countryside) and vineyards in

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