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90-400: The concept of a single source has little meaning for most of the rivers of Greece, which begin as a confluence of multiple springs in the mountain valleys. There is almost never just one, although most may be unreported or neglected. Thus it is appropriate to speak "a source" or "the sources" but never "the source." Nevertheless, competing villages sometimes claim to own "the source." Moreover,

180-425: A catchment area is used to describe the influence from which a retail location draws its customers. Airport catchment areas can inform efforts to estimate route profitability. A health catchment area is of importance in public health , and healthcare planning, as it helps in resource allocation , service delivery, and accessibility assessment. A catchment area can be defined relative to a location, and based upon

270-501: A forested morass about 755 m (826 yd) long by 68 m (74 yd) wide, beginning slightly to the west on the north side of a field with a characteristic semicircular north end. The morass is bisected by the old railway to Anthochori. This sink is supplied with water from several intermittent streams forming the apex of a dendritic pattern. They fall into a basin below the 400 m (440 yd) contour lines. The crossing points are marked by V-gullies located 1 to 2 km from

360-530: A number of factors, including distance, travel time, geographic boundaries or population within the catchment. Catchment areas generally fall under two categories, those that occur organically, i.e., "de facto" catchment area, and a place people are naturally drawn to, such as a large shopping centre. A catchment area in terms of a place people are drawn to could be a city, service or institution. Catchment area boundaries can be modeled using geographic information systems (GIS). There can be large variability in

450-519: A pioneer of the study of karst in Slovenia and a fellow of the Royal Society , London, introduced the word karst to European scholars in 1689 to describe the phenomenon of underground flows of rivers in his account of Lake Cerknica . Jovan Cvijić greatly advanced the knowledge of karst regions to the point where he became known as the "father of karst geomorphology". Primarily discussing

540-587: A population that uses its services and economic opportunities. Catchment areas may be defined based on from where people are naturally drawn to a location (for example, a labour catchment area ) or as established by governments or organizations such as education authorities or healthcare providers, for the provision of services. Governments and community service organizations often define catchment areas for planning purposes and public safety such as ensuring universal access to services like fire departments, police departments, ambulance bases and hospitals. In business,

630-579: A product of the Continental drift theory and its modern development, plate tectonics , which prevailed after 1958. The earliest ideas of the Hellenic orogeny are a product of the previous Geosyncline theory , in which the mountains of the Earth were believed to have been raised by compression of large depressions, or geosynclines, caused by shrinkage, and infilled with sediment. It was hypothesized that

720-582: A proper noun, the Slovene form Grast was first attested in 1177. Ultimately, the word is of Mediterranean origin. It has also been suggested that the word may derive from the Proto-Indo-European root karra- 'rock'. The name may also be connected to the oronym Kar(u)sádios oros cited by Ptolemy , and perhaps also to Latin Carusardius . Johann Weikhard von Valvasor ,

810-477: A river requires a source. If the Alpheios is a permanently flowing river, then there must be a place of higher elevation where the flow begins, and that is by definition the source. Water comes from a multiplicity of sources. A definite river, however, must have a definite source. The distance along the river from mouth to source is the length. Lengths, however, like catchments, are not geodetic . They do not take

900-438: A severely dendritic ridge from which there is no clear connection to the stream below. In ancient times it must have had its own springs, or it could not have survived, but the streams coming from the mountain are more of a tributary nature. The stream below comes from further up the valley. The head of the valley is labelled kato Dorizos on some maps. Ano Dorizos like ano Asea is up on a ridge and has no identifiable connection to

990-402: A specific volume, the catchment may be used to limit a population's ability to access services outside that area. In the case of a school catchment area, children may be unable to enroll in a school outside their catchment to prevent the school's services being exceeded. GIS can also inform for the establishment of health care or hospital catchment areas. Such catchment areas can also define

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1080-401: A sport than a science and so the underground karst caves and their associated watercourses were, from a scientific perspective, understudied. Karst is most strongly developed in dense carbonate rock , such as limestone, that is thinly bedded and highly fractured . Karst is not typically well developed in chalk , because chalk is highly porous rather than dense, so the flow of groundwater

1170-569: A stock phrase "the largest of the Peloponnesus," paraphrased by most of the sources, without definition or evidence. These lengths, representing the general trend, aim at a single location, about 4.2 km (2.6 mi) due south of Megalopoli , where the topographic maps show the beginning of a single stream. Megalopoli is situated on a divide between the Alpheios and its tributary, the Elisson, at about 405 m (1,329 ft). The start of

1260-420: A variety of spatial and temporal scales in karst regions, with the purpose of understanding karst aquifers and ecosystems, and the development of the surface and underground structure, so that the environment can be protected and human activities planned effectively. Catchment area A catchment area in human geography , is the area from which a location, such as a city, service or institution, attracts

1350-529: 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. For example, in the Barton Springs Edwards aquifer, dye traces measured

1440-505: Is a UNESCO World Heritage Site. Many karst-related terms derive from South Slavic languages , entering scientific vocabulary through early research in the Western Balkan Dinaric Alpine karst. The study of the various aspects of karst regions is called karstology. This includes biological, chemical, ecological, geomorphological, hydrogeological, hydrological, political, socio-economical, and other processes over

1530-562: Is a development of karst observed in geological history and preserved within the rock sequence, effectively a fossil karst. There are for example palaeokarst surfaces exposed within the Clydach Valley Subgroup of the Carboniferous Limestone sequence of South Wales which developed as sub-aerial weathering of recently formed limestones took place during periods of non-deposition within the early part of

1620-538: Is a karst landscape which is developed beneath a cover of insoluble rocks. Typically this will involve a cover of sandstone overlying limestone strata undergoing solution. In the United Kingdom for example extensive doline fields have developed at Cefn yr Ystrad , Mynydd Llangatwg and Mynydd Llangynidr in South Wales across a cover of Twrch Sandstone which overlies concealed Carboniferous Limestone ,

1710-611: Is characterized by features like poljes above and drainage systems with sinkholes and caves underground. There is some evidence that karst may occur in more weathering -resistant rocks such as quartzite given the right conditions. Subterranean drainage may limit surface water, with few to no rivers or lakes. In regions where the dissolved bedrock is covered (perhaps by debris) or confined by one or more superimposed non-soluble rock strata, distinctive karst features may occur only at subsurface levels and can be totally missing above ground. The study of paleokarst (buried karst in

1800-399: Is clear that it wouldn't be located in the villages of Asea or Dorizos perched on the mountain ridges. Those names are simply convenient hooks on which to hang a source imagined to be there by offsite geographers looking for a mystic connection to Tripoli. The failure to find a source in the valley causes some to abandon the upper Alpheios in favor of its tributary, the Elisson, flowing out of

1890-468: Is developed in areas where salt is undergoing solution underground. It can lead to surface depressions and collapses which present a geo-hazard. Karst areas tend to have unique types of forests. The karst terrain is difficult for humans to traverse, so that their ecosystems are often relatively undisturbed. The soil tends to have a high pH, which encourages growth of unusual species of orchids, palms, mangroves, and other plants. Paleokarst or palaeokarst

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1980-636: Is frequently unseen until the roof of a cavern suddenly collapses. Such events have swallowed homes, cattle, cars, and farm machinery. In the United States, sudden collapse of such a cavern-sinkhole swallowed part of the collection of the National Corvette Museum in Bowling Green, Kentucky in 2014. The world's largest limestone karst is Australia's Nullarbor Plain . Slovenia has the world's highest risk of sinkholes, while

2070-437: Is not a constant either of measurement or of nature. The measurer working his way along the river encounters many points requiring a decision. For example, the Alpheios divides itself around midstream islands at many points. The river distance through the island zone depends on the stream chosen or the average decided upon. If the river has been impounded or widened by the works of man, the estimator must decide which course through

2160-399: Is not concentrated along fractures. Karst is also most strongly developed where the water table is relatively low, such as in uplands with entrenched valleys , and where rainfall is moderate to heavy. This contributes to rapid downward movement of groundwater, which promotes dissolution of the bedrock, whereas standing groundwater becomes saturated with carbonate minerals and ceases to dissolve

2250-621: Is the following: In very rare conditions, oxidation can play a role. Oxidation played a major role in the formation of ancient Lechuguilla Cave in the US state of New Mexico and is presently active in the Frasassi Caves of Italy. The oxidation of sulfides leading to the formation of sulfuric acid can also be one of the corrosion factors in karst formation. As oxygen (O 2 )-rich surface waters seep into deep anoxic karst systems, they bring oxygen, which reacts with sulfide present in

2340-409: Is the only city of a smaller rift valley elliptical in shape trending North-northwest–south-southeast, 18 km (11 mi) long, area 180 km (69 sq mi), implying an average width of 10 km (6.2 mi). Average altitude is 410 m (1,350 ft). Megalopolis sits on the high point of the central valley, while the Alpheios, sourced in the southeast, skirts the hill to the south,

2430-401: Is the origin of the poet Samuel Taylor Coleridge's reference to the river, by the name Alph, in his poem Kubla Khan , although he transferred the location of the river to Kublai Khan's Mongolia, "where Alph, the sacred river, ran". Karst Karst ( / k ɑːr s t / ) is a topography formed from the dissolution of soluble carbonate rocks such as limestone and dolomite . It

2520-573: Is theorized that these ridges are their own types of rock because they represent separate microcontinents that migrated across Tethys Sea from Gondwana and docked against Eurasia during the compressional regime of the Hellenic orogeny , a branch of the Alpine orogeny , when parts of the African plate were being pushed against the Eurasian plate and being subducted under it. The isotopic zones are

2610-401: Is to be considered the Alpheios, no strict definition applies. Local names do not appear on the maps; instead any or all are likely to be labeled Alpheios. The stepped-off length of the river up to the morass, about 101 km (63 mi), does not fit any of the lengths or source locations given by the publications. These lengths must include the continuous stream plus one intermittent stream,

2700-473: The Alpheus as flowing under the sea to resurface at Ortygia on Sicily , or "so runs the tale". The nymph Arethusa , who was transformed into a fountain, was called Alpheias because it was believed that her stream had a subterraneous communication with the river Alpheius. The river disappears several times into the limestone Arcadian mountains and reemerges after flowing some distance underground. This

2790-631: The Hellenic orogeny , becoming different modern zones of rock. Subsequent to the compressional regime back-arc extension of the Hellenic arc , the outer ring of islands, opened the Aegean Sea and initiated the extensional regime that is opening the Peloponnesus. Fortuitously the right bank of the Alpheios Valley became a defensive zone for the protection of central Arcadia. During the so-called Dorian invasion starting about 1000 BC iron-age highlanders ( Dorians ) from central Greece overran

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2880-636: The range of the Dinaric Alps , stretching from the northeastern corner of Italy above the city of Trieste , across the Balkan peninsula along the coast of the eastern Adriatic to Kosovo and North Macedonia , where the massif of the Šar Mountains begins. The karst zone is at the northwesternmost section, described in early topographical research as a plateau between Italy and Slovenia . Languages preserving this form include Italian : Carso , German : Karst , and Albanian : karsti . In

2970-435: The stratigraphic column ) is important in petroleum geology because as much as 50% of the world's hydrocarbon reserves are hosted in carbonate rock , and much of this is found in porous karst systems. The English word karst was borrowed from German Karst in the late 19th century, which entered German usage much earlier, to describe a number of geological, geomorphological, and hydrological features found within

3060-503: The "40 rivers" region of the high plateau of central Arcadia (around Tegea and Mantineia , etc.). The Alpheios of today bears little resemblance to the historical Alpheios. Much of it has been widened by damming; large sections have been straightened by embankments; flood control works have been constructed; water for municipal use and irrigation is diverted all along the course; some sections are used for gravel mining; and waste water, fertilizer, and pesticides pollute it from one end to

3150-478: The Alpheios a large river (over 1000 km. basin). The uppermost part of the Alpheios basin, at Karytaina , upstream from its confluence with the Lousios , is 868.6 km (335.4 sq mi). The maximum elevation is 2,253 m (7,392 ft) with a mean elevation of 648 m (2,126 ft). The mean slope is about 14 deg. The catchment is about 25% of the 15,511 km (5,989 sq mi) map area of

3240-462: The Alpheios around the mined area is the natural one around the base of the hill. Mining began on the slopes and worked its way down the hill. The river was not diverted or rerouted, as there is no other possible course. Rather, until recently, the river was respected as a border to the mine. Currently the mine has pushed across the river on the SW side of the hill. When the river is full, it occupies parts of

3330-566: The Greek Ministry of Environment, Energy and Climate Change. A research group of the National Technical University of Athens found the same area, within (but not equal to) the rectangle 38°0′N 21°15′E  /  38.000°N 21.250°E  / 38.000; 21.250 and 37°20′N 22°20′E  /  37.333°N 22.333°E  / 37.333; 22.333 . By HCMR standards, this makes

3420-407: The Peloponnesus. The major part of the basin is mountainous, with 52.5% of the catchment map being over 600 m. The rest is hilly (100 - 600 m, 36.9%) and flat along the coast (10.5%). The political distribution is 60% Arcadia , 30% Elis , and 10% Achaea . Arcadia accounts for most of the mountainous and hilly terrain. Achaea shares some of the mountainous terrain to the north, while Elis contains

3510-494: The SW to enter the morass about 1 km away. From the road the river appears as a deep V-shaped ditch lined densely with trees over which a plank walkway has been placed. Above the 400 m line the stream drops in a long flow across the base of the Mainalo Mountains from the valley leading up to Tripoli on the high plateau. It generally follows the direction of Rt. E65, the lowland version of Rt. 7, which winds through

3600-706: The Tripolitsa, the Pindos, and the Parnassos. To the east are the inner Hellenides, partly volcanic, with the dividing line down the center of Greece. They end at the Chalcidic Peninsula, beyond which are the Rhodope and Serbomacedonian massifs. Mathematical hydrology requires definite numbers: rivers have lengths, cross-sections, measurable linear and volumetric (discharge) rates of flow. The length of

3690-451: The URCA and FEA is that the models link locations to a single urban center of reference, even though there may be multiple centers of reference for varying activities. Catchment areas may be established for the provision of services. For example, a school catchment area is the geographic area from which students are eligible to attend a local school. When a facility's capacity can only service

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3780-441: The ages wishes to connect the Alpheios of Megalopoli to Tripoli. If the Alpheios is defined as a continuously flowing stream, then it must begin at Megalopoli. Intermittent dendritic streams come from higher, but there is no evidence that they follow any tunnel through the Mainalo Mountains to trickle out as springs at this or that lower location. The main lower locations promulgated by some are Davia, Dorizas, and Asea . Megalopolis

3870-511: The bedrock. The carbonic acid that causes karst features is formed as rain passes through Earth's atmosphere picking up carbon dioxide (CO 2 ), which readily dissolves in the water. Once the rain reaches the ground, it may pass through soil that provides additional CO 2 produced by soil respiration . Some of the dissolved carbon dioxide reacts with the water to form a weak carbonic acid solution, which dissolves calcium carbonate . The primary reaction sequence in limestone dissolution

3960-461: The bronze-age coastal regions of the Peloponnesus, expelling or subjugating the Mycenaean population there, but could not ascend the right-bank mountains to take central Arcadia. The population there maintained its culture ( Arcado-Cypriot ) and political independence. The Dorians kept the valley, which accounts for the predominance of Doric architecture at Olympia. In their 2003 master plan for

4050-450: The complexity of karst aquifers, and 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

4140-415: The curvature of the Earth into consideration nor the elevations of the terrain. For example, seen from above, a waterfall is only a few feet of river length, yet the stream may fall hundreds of uncounted feet. Map work for measuring the general morphology of rivers relies on the conformal map , pieced together from satellite photographs and topographic maps. The length of a river by any system of measurement

4230-567: The dictum of one source preventing the choice of more than one. Every stream has been proposed by someone. Flow in the intermittent streams is guided by two tilts of the valley floor: a drop from N to S draining the Mainalo Mountains and a drop from E to W draining Taygetus. The generally preferred candidate for the title of upper Alpheios drops through the 400 m (1,300 ft) elevation line at 37°22′35″N 22°08′53″E  /  37.3763095°N 22.1481159°E  / 37.3763095; 22.1481159 as it crosses under Rt. 7 and turns to

4320-424: The epidemiological disease burdens or forecast hospital needs amid a disease outbreak. They are used to evaluate population health outcomes, especially for diseases like cancer and chronic conditions . Understanding the catchment area helps health systems optimize service coverage, measure healthcare utilization, and identify underserved regions. Health catchment areas are often employed in research to study

4410-557: 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

4500-466: The global demand for drinkable water. Farming in karst areas must take into account the lack of surface water. The soils may be fertile enough, and rainfall may be adequate, but rainwater quickly moves through the crevices into the ground, sometimes leaving the surface soil parched between rains. The karst topography also poses peculiar difficulties for human inhabitants. Sinkholes can develop gradually as surface openings enlarge, but progressive erosion

4590-882: The impoundment applies. The length also depends on the method of estimation. Representation of the river by small straight-line segments depends entirely on the segmentation decisions made. Nature itself does not provide reliable and exact lengths. Rivers change course in history (let alone geologic history) to such a degree that they are typically different from century to century, as the geology of erosion teaches they must be. The publication sources therefore give riverine lengths and locations that are different from each other, unless one source copies another. The length can be assumed to have been measured at least one or more years before publication, many years if one source relies on another. Some lengths are 110 km (68 mi), 111 km (69 mi), 112 km (70 mi), 113 km (70 mi). Encyclopædia Britannica uses 110 km with

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4680-471: The interconnectedness of urban centers. The Nature Cities article “Worldwide Delineation of Multi-Tier City–Regions” maps the catchment areas of urban centers across four tiers—town, small, intermediate, and large city—based on travel time using a global travel friction grid, acknowledging that individuals may rely on multiple centers for various needs, with larger centers offering a wider range of activities. The dataset, classifying over 30,000 urban centers into

4770-629: The interior. The dendrism is mainly right-bank. On the left is the long ridge of Mount Lykaion , relatively uneroded, suggesting that different types of rock occur on either side. After a divide the ridge continues as Mount Taygetus, and the valley as the Eurotas River valley, which extends south to the Gulf of Lakonia . The entire southwest Peloponnesus is split from Arcadia by this great trough, considered two basins, which must have been in place in some form before any extensive dendrism. Scarps along

4860-456: 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. Groundwater in karst areas is also just as easily polluted as surface streams, because Karst formations are cavernous and highly permeable, resulting in reduced opportunity for contaminant filtration. Well water may also be unsafe as

4950-534: The karst regions of the Balkans, Cvijić's 1893 publication Das Karstphänomen describes landforms such as karren, dolines and poljes . In a 1918 publication, Cvijić proposed a cyclical model for karst landscape development. Karst hydrology emerged as a discipline in the late 1950s and the early 1960s in France. Previously, the activities of cave explorers, called speleologists , had been dismissed as more of

5040-562: The last-named locality having been declared a site of special scientific interest in respect of it. Kegelkarst is a type of tropical karst terrain with numerous cone-like hills, formed by cockpits, mogotes , and poljes and without strong fluvial erosion processes. This terrain is found in Cuba, Jamaica, Indonesia, Malaysia, the Philippines, Puerto Rico, southern China, Myanmar, Thailand, Laos and Vietnam. Salt karst (or 'halite karst')

5130-631: The length east of Olympia. In Greek mythology , the Peneus and Alpheus were two rivers re-routed by Heracles in his fifth labour in order to clean the filth from the Augean Stables in a single day, a task which had been presumed to be impossible. A poem by Roger Caillois , called Le fleuve Alphée (the Alpheus River), is mainly about this river. In the Aeneid , Virgil describes

5220-412: The local South Slavic languages , all variations of the word are derived from a Romanized Illyrian base (yielding Latin : carsus , Dalmatian : carsus ), later metathesized from the reconstructed form * korsъ into forms such as Slovene : kras and Serbo-Croatian : krš , kras , first attested in the 18th century, and the adjective form kraški in the 16th century. As

5310-440: The lowlands and some of the hilly terrain. The 2006 HCMR article defines three river zones of Greece, a "zone" being a region of a similar geophysical terrain, which influences the chemical composition and physical morphology of the rivers in it. Zones 1, 2, and 3, are based on the geologic isopic ("same facies ") zones, or tectono-stratigraphic units of Greece, which are ridges of distinct rock trending northwest to southeast. It

5400-533: The management of Greek water resources, the then Hellenic Ministry of Development , one of the many Greek governmental agencies that have been responsible for the monitoring and care of Greek rivers, noted that of the 765 recorded rivers in Greece, 45 were permanently flowing, of which the Alpheios is one. Although the Greek government had been monitoring some rivers since the 1970s, classification and monitoring of rivers

5490-479: The mine, giving it the appearance of a lake on the maps. The lake is, however, only an intermittent puddle. The source of the river is on the southeast of the mine in the district still called Anthochori ("flowery place"), once a pleasant village, and still advertised as that in the media. It does not exist, except for a few outlying farm buildings. The villagers in 2006 coming under pressure to sell and move away yielded in 2008 after painful negotiations. The village

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5580-500: The modeling of catchment areas, and in particular those relating to urban areas. Based on travel time between rural areas and cities of different sizes, the urban–rural catchment areas (URCAs) is a global GIS dataset that allows for comparison across countries, such as the distribution of population along the rural–urban continuum. Functional economic areas (FEAs), also called larger urban zone or functional urban areas, are catchment areas of commuters or commuting zones . A limitation of

5670-667: The morass: one due south, two west, one NE, and one N from Megalopoli through the mine. These streams are in the small tributary category, some mere thicketed ditches, others with pebble beds and forested banks cutting across the rolling upland. Water levels vary from zero to meandering flows or trickles. They are visible at roads crossing over them; for example, crossing Rt. 7 at 37°21′36″N 22°08′12″E  /  37.359884°N 22.136688°E  / 37.359884; 22.136688 or 37°22′35″N 22°08′53″E  /  37.37650°N 22.14809°E  / 37.37650; 22.14809 . As to whether this uppermost "tree" of streams

5760-647: The most dramatic of these formations can be seen in Thailand 's Phangnga Bay and at Halong Bay in Vietnam . Calcium carbonate dissolved into water may precipitate out where the water discharges some of its dissolved carbon dioxide. Rivers which emerge from springs may produce tufa terraces, consisting of layers of calcite deposited over extended periods of time. In caves, a variety of features collectively called speleothems are formed by deposition of calcium carbonate and other dissolved minerals. Interstratal karst

5850-420: The mountains NE of Megalopoli with a much stronger flow. It is more of a mountain stream, as can be seen from the bridge at 37°32′43″N 22°16′30″E  /  37.545394°N 22.275098°E  / 37.545394; 22.275098 . It begins shortly upstream at Falanthos, next to Davia, which is closer to Tripoli than Dorizos. Those who hold this view refer to the Elisson as the Alpheios, as though it were

5940-470: The mountains of Greece, called the Hellenides, arose from a Hellenic geosyncline in two phases, a volcanic breakthrough in the center, resulting in the "inner Hellenides," and a subsequent orogeny at the west periphery from the wrinkling of sediment running off the central mountains. The peripheral range was the "outer Hellenides." As both theories featured a compressional regime, the Hellenides terminology

6030-545: The mountains. They all start from the same place, Kato Asea. The stream is visible there from the Agorianis-Koronias Road at 37°23′57″N 22°17′06″E  /  37.399260°N 22.284982°E  / 37.399260; 22.284982 . It is still a deep, thicketed ditch cutting through the farmland. The elevation is 652 m (2,139 ft). The drop from there to 400 is innocuous for the 12.52 km (7.78 mi) straight-line distance, approximating

6120-477: The original sanguine engineering reports of how little land would be consumed, which are still being published, the open area is about 2.5% of the total valley area, with no end to expansion in sight. The main pollutants are the gases. White plumes from the plant facilities have become a feature of the Arcadia landscape. During unfavorable meteorological conditions an opaque smog hangs over the valley. The course of

6210-406: The other. It has been necessary to establish regular monitoring by the government and create substructure to make important decisions concerning the fate of the river. Despite the recent alterations of man and the apparently random dendritic pattern in parts of the valley, a geologic pattern emerges that is too regular to be entirely random. The valley is a regular trough, or basin, from the coast to

6300-709: The period. Sedimentation resumed and further limestone strata were deposited on an irregular karst surface, the cycle recurring several times in connection with fluctuating sea levels over prolonged periods. Pseudokarsts are similar in form or appearance to karst features but are created by different mechanisms. Examples include lava caves and granite tors —for example, Labertouche Cave in Victoria, Australia —and paleocollapse features. Mud Caves are an example of pseudokarst. Karst formations have unique hydrology, resulting in many unusual features. A karst fenster (karst window) occurs when an underground stream emerges onto

6390-620: The relationship between geographical factors and healthcare outcomes. For example, they are used in cancer research to understand the distribution of cases and ensure that healthcare resources are equitably distributed. They are also used in epidemiological studies to assess the reach and impact of healthcare interventions. One challenge in defining catchment areas is that they may not accurately reflect patient behavior or health-seeking patterns, particularly in areas where patients have access to multiple health facilities. Overlapping catchment areas can be used to determine city–regions, reflecting

6480-641: The results appearing in an online report of 2005. Several figures have been reported for the catchment area of the Alpheios. A 2004 study by the Civil Engineering Department of the University of Patras reported 3,658 km (1,412 sq mi), and a 2020 study by a consortium of academic departments including the HCMR reported 3,610 km (1,390 sq mi). The value 3,810 km (1,470 sq mi) has been reported by

6570-504: The right bank of the Alpheios, finishing two plants in 1970 and one in 1975. To obtain the lignite, they began strip-mining the region to the west of the city, working the mine southward, then eastward. Stripping essentially removed many meters of the hill. Areas so flattened were then planted with grass. Today the original strip mine is grassy, but the south is open over a rough rectangle 1.3 km (0.81 mi) N–S by 3.4 km (2.1 mi) E–W, or 4.4 km (1.7 sq mi). Despite

6660-780: The river flows into a cave in a formation known as the Madison Limestone and then rises again 800 m ( 1 ⁄ 2  mi) down the canyon in a placid pool. A turlough is a unique type of seasonal lake found in Irish karst areas which are formed through the annual welling-up of water from the underground water system. Main Article Aquifer#Karst 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

6750-456: The services provided within different catchment areas in the same region depending upon how and when those catchments were established. They are usually contiguous but can overlap when they describe competing services. For example, the boundaries of catchment areas can also vary by travel time, whereby 1-hour is indicative of daily commuting time and a 3-hour cut-off reflecting essential, but less frequent services. GIS technology has allowed for

6840-481: The single stream is at about 380 m (1,250 ft). The dendritic terrain of the upper Alpheios ascends to central Arcadia by steps. The plateau of Megalopoli is intermediate between the lowlands and the capital of Arcadia, modern Tripoli at 652 m (2,139 ft). Between the two are the Tsemperou and Mainalo mountains, which are well over 1,000 m (3,300 ft). Unsupported speculation throughout

6930-431: The sources are not geologically stable, but change frequently in history. In karst terrain, such as the Peloponnesus, the population is acutely aware that rivers may run underground for some distance. Thus the "source" of the Alpheios has always been a subject of debate and literary fantasies, some wild by modern geologic standards. Most recently attempts have been made to connect the Alpheios through underground channels to

7020-445: The stream fairly well. Over that distance various tributary ditches descend from the mountains, which should not be confused with the main stream. The 13.52 km to kato Asea does much to fill the gap between the morass and the legacy distances, but there is a further fiction involved. The main village, Asea or ano Asea ("upper Asea" as opposed to "lower Asea") is located at 840 m (2,760 ft), 2.64 km (1.64 mi) up on

7110-445: The streams below, which are in a highly dendritic pattern of dry and wet ditches. The land around Dorizos displays a network of shallow ditches, hardly different from the fields they traverse. Rt. 7 goes over a pass to Tripoli, while Rt. E65 goes under it through tunnels. Long before the tunnel point the dendritic ditches have disappeared into the mountainside. There is nothing like a source in the entire upper valley, but if there were, it

7200-649: The surface between layers of rock, cascades some distance, and then disappears back down, often into a sinkhole. Rivers in karst areas may disappear underground a number of times and spring up again in different places, even under a different name, like Ljubljanica , the "river of seven names". Another example of this is the Popo Agie River in Fremont County, Wyoming , where, at a site named "The Sinks" in Sinks Canyon State Park ,

7290-415: The surface, complex underground drainage systems (such as karst aquifers ) and extensive caves and cavern systems may form. Erosion along limestone shores, notably in the tropics , produces karst topography that includes a sharp makatea surface above the normal reach of the sea, and undercuts that are mostly the result of biological activity or bioerosion at or a little above mean sea level . Some of

7380-1002: The system ( pyrite or hydrogen sulfide ) to form sulfuric acid (H 2 SO 4 ). Sulfuric acid then reacts with calcium carbonate, causing increased erosion within the limestone formation. This chain of reactions is: This reaction chain forms gypsum . The karstification of a landscape may result in a variety of large- or small-scale features both on the surface and beneath. On exposed surfaces, small features may include solution flutes (or rillenkarren), runnels , limestone pavement (clints and grikes), kamenitzas collectively called karren or lapiez. Medium-sized surface features may include sinkholes or cenotes (closed basins), vertical shafts, foibe (inverted funnel shaped sinkholes), disappearing streams, and reappearing springs . Large-scale features may include limestone pavements , poljes , and karst valleys. Mature karst landscapes, where more bedrock has been removed than remains, may result in karst towers , or haystack/eggbox landscapes. Beneath

7470-440: The trough suggest that the two basins are rift valleys , depressions, or graben , caused by the ridges on each side moving away from each other. The whole, finger-like arrangement of the ridges in the south Peloponnesus is currently explained as a stretching, or extension , of the Peloponnesus in a NE-SW direction, pulling the troughs apart. The division between the ridges occurs because they were primordially compressed together in

7560-553: The true upper Alpheios. At Thoknia it receives its right tributary Elissonas , and continues north towards Karytaina . Below Karytaina the Lousios flows into the Alpheios, which continues northwest, passing north of Andritsaina . Near Tripotamia the rivers Ladon and Erymanthos flow into the Alpheios, which then flows west along Olympia and empties into the Ionian Sea south of Pyrgos . The ancient highway linking Patras and Kalamata ran along this river for most of

7650-461: The water may have run unimpeded from a sinkhole in a cattle pasture, bypassing the normal filtering that occurs in a porous aquifer . Sinkholes have often been used as farmstead or community trash dumps . Overloaded or malfunctioning septic tanks in karst landscapes may dump raw sewage directly into underground channels. Geologists are concerned with these negative effects of human activity on karst hydrology which, as of 2007 , supplied about 25% of

7740-507: The west, and exits to the NW dropping through a steep and impassible gorge. A former defense against enemies on foot, the gorge is popular for its recreational rafting over rapids, justifying the ancient etymology of "whitewater." The uppermost river is blighted by the open-pit mining of lignite . In 1969 the Megalopoli power company opened a lignite-burning facility to the NW of the city on

7830-515: The western Highland Rim in the eastern United States is at the second-highest risk of karst sinkholes. In Canada, Wood Buffalo National Park , Northwest Territories contains areas of karst sinkholes. Mexico hosts important karst regions in the Yucatán Peninsula and Chiapas . The West of Ireland is home to The Burren , a karst limestone area. The South China Karst in the provinces of Guizhou , Guangxi , and Yunnan provinces

7920-408: Was demolished. The last building down, a church atop a standing column, became the subject of some prize-winning photography internationally. The single, continuous stream is marked on the current internet topographical maps at 37°21′54″N 22°08′02″E  /  37.36499°N 22.13397°E  / 37.36499; 22.13397 , 380 m (1,250 ft) of elevation. The point falls within

8010-533: Was kept, but it had to be matched to the isopic zones. The Alpheios falls within river zone 3, the Outer Hellenides, an arc-like range continuing the Dinarides of the Balkans into western Greece, comprising most of the Peloponnesus, and including the southernmost arc of Aegean islands, with Crete, around to the coast of Anatolia ( Hellenic arc ). The isopic zones included, west to east, are The Ionian,

8100-579: Was not mandated by the European Union until the Water Framework Directive (WFD) of 2000. The EU was interested in identifying quality problems with the waters of Europe and rescuing degraded waters. The Hellenic Center for Marine Research (HCMR) therefore added the study of water quality in Greece to its previously existing AQEM program. Select river sites were monitored for three seasons of 2000–2001, spring, summer, and winter,

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