Modern Greek
Modern Greek (, or , ), generally referred to by speakers simply as Greek (, ), refers collectively to the dialects of the Greek language spoken in the modern era, including the official standardized form of the language sometimes referred to ...
: ) or Eurotas () is the main river of
Laconia
Laconia or Lakonia (, , ) is a historical and Administrative regions of Greece, administrative region of Greece located on the southeastern part of the Peloponnese peninsula. Its administrative capital is Sparti (municipality), Sparta. The word ...
and one of the major rivers of the
Peloponnese
The Peloponnese ( ), Peloponnesus ( ; , ) or Morea (; ) is a peninsula and geographic region in Southern Greece, and the southernmost region of the Balkans. It is connected to the central part of the country by the Isthmus of Corinth land bridg ...
, in
Greece
Greece, officially the Hellenic Republic, is a country in Southeast Europe. Located on the southern tip of the Balkan peninsula, it shares land borders with Albania to the northwest, North Macedonia and Bulgaria to the north, and Turkey to th ...
. The river's springs are located just northwest of the border between Laconia and Arcadia, at Skortsinos. The river is also fed by underwater springs at Pellana and by tributaries coursing down from Mt. Taygetos and Mt. Parnon, which flank the
Evrotas Valley
The Evrotas Valley is an 82 km elongated valley between Taygetus and Parnon which traverses Laconia, Greece. Homer called the valley Kili Lakedemon, while Sparta, Mystras and Gytheio are the main cities within the valley. It is one of the larg ...
to the west and east, respectively. The river is long, flowing in a north-south direction and emptying into the Laconian Gulf. Its
drainage basin
A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, ...
is .
Etymology
The classical Evrotas was changed to Iri in the Middle Ages and only changed back to Evrotas in recent times. Evrotas, however, is not the most ancient name of the river. It does not appear in the works of
Homer
Homer (; , ; possibly born ) was an Ancient Greece, Ancient Greek poet who is credited as the author of the ''Iliad'' and the ''Odyssey'', two epic poems that are foundational works of ancient Greek literature. Despite doubts about his autho ...
, which purport to recount the stories and geography of
Mycenaean Greece
Mycenaean Greece (or the Mycenaean civilization) was the last phase of the Bronze Age in ancient Greece, spanning the period from approximately 1750 to 1050 BC.. It represents the first advanced and distinctively Greek civilization in mainla ...
. In that legendary time, the
Dorians
The Dorians (; , , singular , ) were one of the four major ethnic groups into which the Greeks, Hellenes (or Greeks) of Classical Greece divided themselves (along with the Aeolians, Achaeans (tribe), Achaeans, and Ionians). They are almost alw ...
are not known to have been present in the
Evrotas Valley
The Evrotas Valley is an 82 km elongated valley between Taygetus and Parnon which traverses Laconia, Greece. Homer called the valley Kili Lakedemon, while Sparta, Mystras and Gytheio are the main cities within the valley. It is one of the larg ...
. At some time prior to being called Evrotas, the river was the Bomycas and the Himeras.
One etymology derives the word Eurōtas from the
ancient Greek
Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...
eurōs (εὐρώς), "mold".. The adjective, eurōeis, "moldy," is genuinely ancient, used as an epithet of
Hades
Hades (; , , later ), in the ancient Greek religion and Greek mythology, mythology, is the god of the dead and the king of the Greek underworld, underworld, with which his name became synonymous. Hades was the eldest son of Cronus and Rhea ...
in Homer. It is, however, in the
Ionic dialect
Ionic or Ionian Greek () was a subdialect of the Eastern or Attic–Ionic dialect group of Ancient Greek. The Ionic group traditionally comprises three dialectal varieties that were spoken in Euboea (West Ionic), the northern Cyclades (Central ...
.
Geography
Physical
Sources
The source of the Evrotas River is a surface spring called Piges Evrota (Πηγές Ευρώτα, "Eurotas Springs") located near the village of Skortsinos, Arcadia, by the side of the road ascending from Kyparissi. The spring is an outlet of an
aquifer
An aquifer is an underground layer of water-bearing material, consisting of permeability (Earth sciences), permeable or fractured rock, or of unconsolidated materials (gravel, sand, or silt). Aquifers vary greatly in their characteristics. The s ...
located in the adjacent
limestone
Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...
ridge at a locale called Kephalari. The ridge, a
karst
Karst () is a topography formed from the dissolution of soluble carbonate rocks such as limestone and Dolomite (rock), dolomite. It is characterized by features like poljes above and drainage systems with sinkholes and caves underground. Ther ...
, is not part of the
Taygetus
The Taygetus, Taugetus, Taygetos or Taÿgetus () is a mountain range on the Peloponnese peninsula in Southern Greece. The highest mountain of the range is Mount Taygetus, also known as "Profitis Ilias", or "Prophet Elias" (Elijah).
The name is o ...
Massif, but, like the other mountains of Arcadia, is a nappe raised by the compressional forces on the Hellenic Plate by the subduction of Africa. The spring is also called Logaras Spring.
Logaras Spring supplies an anciently constructed catchment basin about the size of a pond, sometimes called a lake, which exits both to irrigation channels and to the Alpheios stream (not to be confused with the Alpheios river in the northwestern Peloponnese). The flow is copious except in times of drought. A recent study measured the outflow through the catchment exit every 15 days for 540 days in 2006-2007. It recorded a maximum of 1748 cubic m per hour and a minimum of 310.5 cubic m per hour. From the catchment at an altitude of part of the water flows into the Alpheios stream, which enters the upper Eurotas.
The Laconian Alpheios stream is unconnected with the Alpheios river in Arcadia. The identity of their names comes from an ancient geologic misunderstanding that the Eurotas and the Apheios were connected underground, which deceived even Pausanias, one of the best ancient geographers. He believed they had the same source but that the outflow stream disappeared into a chasm only to emerge at different locations as different streams. In the most exaggerated form of the myth, the Alpheios continues under the Mediterranean to Sicily or elsewhere.
Main stream
Today, the river is hydromorphologically far from its natural state. The main problem is anthropogenic abstraction of water, by many methods, from the shallow aquifer through which it flows. The valley contains about 7000 wells. Water is directly removed by irrigation ditches, weirs, and pumping stations. Consequently, the river is intermittent; large sections are typically dry of surface water, even though water still flows in the aquifers. Flash flooding is a problem. Through flood control, the riverbed has been widened in places and straightened, and the vegetation has been removed from its sides. The lower river runs between dikes in a long, straight course.
Tributaries
Most of the numerous tributaries of the Eurotas are right-bank, feeding the shallow aquifer. They are, however, intermittent and ephemeral. The major ones have cut deep ravines into the Taygetus Massif. The few left-bank tributaries, receiving waters from the deep aquifer, are more substantial, but still intermittent.
The classical Oineus was changed to Kelefina in the Middle Ages and not restored to its ancient name until recent times. The current Magoulitsa was formerly the Trypiotiko.
Delta
The rich alluvial soil through which the final 10 km of the Eurotas flows was not there in antiquity. The Eurotas has aggraded the innermost bay of the gulf. The old coastline can be approximated by a line on the periphery of the plain of
Elos
Elos (, before 1930: Δουραλί - ''Dourali'') is a village and a former municipality in Laconia, Peloponnese, Greece. Since the 2011 local government reform it is part of the municipality Evrotas, of which it is a municipal unit. The municip ...
marking the border within which prehistoric archaeological sites are not found. The line on the west follows the Skala- Gytheion road to Skala, the Skala-
Molaoi
Molaoi () is a town and a former municipality in Laconia, Peloponnese, Greece. Since the 2011 local government reform it is part of the municipality Monemvasia, of which it is the seat and a municipal unit. The municipal unit has an area of 193.167 ...
road to Vlachiotis, southeast along the edge of the rising terrain to Asteri and south from there to the coast. Due to changes in sea level, some land on the flanks of the gulf has been drowned.
The current communities of Elos, Leimonas and Agioi Taxiarches have been constructed on aggraded land. As Pausanias mentions that Elos was a port city, the current Elos cannot be identified with it. Skala, on the other hand, means "place of embarkation." The location of the ancient port, however, is not yet known for certain.
Political
Legendary pre-Hellenic tribe
In Greek legend, the human ancestor of all the peoples that inhabited the Eurotas Valley was Lelex,
eponym
An eponym is a noun after which or for which someone or something is, or is believed to be, named. Adjectives derived from the word ''eponym'' include ''eponymous'' and ''eponymic''.
Eponyms are commonly used for time periods, places, innovati ...
ous king of the
Leleges
The Leleges (; ) were an aboriginal people of the Aegean Sea, Aegean region, before the Greek people, Greeks arrived. They were distinct from another pre-Hellenic people of the region, the Pelasgians. The exact areas to which they were native are u ...
, one of the peoples of the eastern Aegean whom the classical writers saw as autochthonous; that is, indigenous and pre-Hellenic. His son or grandson was
Eurotas
In Greek mythology, Eurotas (; Ancient Greek: Εὐρώτας) was a king of Laconia. Family
Eurotas was the son of King Myles of Laconia and grandson of Lelex, eponymous ancestor of the Leleges. The ''Bibliotheca (Pseudo-Apollodorus), Bibliothe ...
, the last of the line. The latter had a daughter, Sparta, but no sons. An outsider married her, Lacedaemon. Although he named the state Sparta after her, his name is now known to have most likely been the name of the Mycenaean state.
Mycenaean, or
late Bronze Age
The Bronze Age () was a historical period characterised principally by the use of bronze tools and the development of complex urban societies, as well as the adoption of writing in some areas. The Bronze Age is the middle principal period of ...
Linear B
Linear B is a syllabary, syllabic script that was used for writing in Mycenaean Greek, the earliest Attested language, attested form of the Greek language. The script predates the Greek alphabet by several centuries, the earliest known examp ...
Dorians
The Dorians (; , , singular , ) were one of the four major ethnic groups into which the Greeks, Hellenes (or Greeks) of Classical Greece divided themselves (along with the Aeolians, Achaeans (tribe), Achaeans, and Ionians). They are almost alw ...
that were present were not overtly recorded by the surviving administrative records but by surviving copies of records. Hypothetically, if the Leleges really were in the Eurotas valley, the time of their ascendancy would have been before Mycenaean times.
Until the late 20th century, evidence in the valley of earlier occupation seemed to be lacking. Beginning in 1968 the
University of Cambridge
The University of Cambridge is a Public university, public collegiate university, collegiate research university in Cambridge, England. Founded in 1209, the University of Cambridge is the List of oldest universities in continuous operation, wo ...
began a survey by underwater archaeology of a drowned town between Pounta on the mainland and Elafonisos island on the eastern side of the Laconian Gulf. The town extended over the entire drowned isthmus from 60 rock-cut tombs on the Pounta shore (a beach) to the remains of walls on Pavlopetri island off Elafonisos. A subsequent survey in 2009 discovered even earlier parts of the town and recovered additional pottery. A chronological study was done on "442 ceramic items, an iron nail and an obsidian chip." More research on the site is planned.
The town was apparently continuously occupied from the late Neolithic to Byzantine times when it was drowned, perhaps by an earthquake. Neolithic ceramics were only 3% of the 444 items. The town was mainly Early Bronze Age, which had 40%. The early Helladic pottery is "standard ... some showing close links with the
Cyclades
The CYCLADES computer network () was a French research network created in the early 1970s. It was one of the pioneering networks experimenting with the concept of packet switching and, unlike the ARPANET, was explicitly designed to facilitate i ...
, western
Crete
Crete ( ; , Modern Greek, Modern: , Ancient Greek, Ancient: ) is the largest and most populous of the Greek islands, the List of islands by area, 88th largest island in the world and the List of islands in the Mediterranean#By area, fifth la ...
and the northeastern Aegean." The "15% Middle Bronze Age" is represented by middle Helladic and middle Minoan. This archaeological scenario is not incompatible with the Aegean distribution of the Leleges, although it is not possible to say who the early and middle Bronze Age inhabitants were.
The late Bronze Age had 25% of the items. Classical and Byzantine items were minimal, indicating a probable near abandonment of the city at the end of the late Bronze Age.
Mycenaean Lacedaemon
Archaeology has provided a more complete story for the Mycenaean period. On the left bank of the Eurotas, across from Sparta, is a ridge on which sits a temple called the ''Menelaon''. In the 20th century a survey by the British School of Archaeology revealed that the entire ridge, located in the municipal unit of Therapnes, ancient Therapnē, had been covered by a walled Mycenaean town, dated to the
late Bronze Age
The Bronze Age () was a historical period characterised principally by the use of bronze tools and the development of complex urban societies, as well as the adoption of writing in some areas. The Bronze Age is the middle principal period of ...
by the late Helladic (LH3) pottery with some middle Helladic (MH) pottery in "pockets in the bedrock." The archaeologists analyzing the site recognized a building Period I, dated between LH2B–LH3A1, the latter being brought to and end about 1425 BCE by a severe earthquake. Remains of a mansion with
Minoan
The Minoan civilization was a Bronze Age culture which was centered on the island of Crete. Known for its monumental architecture and Minoan art, energetic art, it is often regarded as the first civilization in Europe. The ruins of the Minoan pa ...
pottery date from Period I.
During Period IA, the hill settlement was rebuilt. The structures included kilns for smelting bronze. In Period II, dated to LH3A1, a villa-type structure was built of a terrace formed from previous building material further down to the south. It was probably two-story,
megaron
The ''megaron'' (; , , : ''megara'' ) was the great hall in very early Mycenae, Mycenean and Ancient Greece, ancient Greek palace complexes. Architecturally, it was a rectangular hall that was supported by four columns, fronted by an open, two- ...
-type, with "less substantial walls" but "a massive foundation for what could be a defense tower." It was connected to the top by stairs. Period III, LH3A2–LH3B2, begins with 150 years of apparent abandonment and then a limited reconstruction of a one-story structure on the terrace. The staircase was blocked. The entire ridge was intensely occupied leaving a profusion of Mycenaean pottery. The villa was burned at the end of LH3B2, leaving a destruction level. Two persons buried in the associated rubble appear to have died violently. Occupation of the hill went on through the
Greek Dark Age
The Greek Dark Ages ( 1180–800 BC) were earlier regarded as two continuous periods of Greek history: the Postpalatial Bronze Age (c. 1180–1050 BC) and the Prehistoric Iron Age or Early Iron Age (c. 1050–800 BC). The last included all the ...
, reduced to the Menelaon shrine in the Archaic and Classical Periods. Dedications to
Menelaus
In Greek mythology, Menelaus (; ) was a Greek king of Mycenaean (pre- Dorian) Sparta. According to the ''Iliad'', the Trojan war began as a result of Menelaus's wife, Helen, fleeing to Troy with the Trojan prince Paris. Menelaus was a central ...
and Helen are found in its vicinity starting the Archaic period.
The excavators concluded that in the "later 15th century" (BC) the ridge was "the principal settlement site in Laconia." The shrine and its dedications identify it as the site of Homeric Sparta, capital of a ruling couple believed by the population of the Archaic Period to have been Menelaos and Helen.
Classical Sparta
The classical-era city of
Sparta
Sparta was a prominent city-state in Laconia in ancient Greece. In antiquity, the city-state was known as Lacedaemon (), while the name Sparta referred to its main settlement in the Evrotas Valley, valley of Evrotas (river), Evrotas rive ...
was built on the west bank of the Eurotas about halfway down the valley. The Spartans made little use of the left bank of the river: Only one permanent bridge has been found that crossed to it, at Therapne just south of the city. The main traffic was southward to the port of
Gytheio
Gytheio ( ) or Gythio, also the ancient Gythium or Gytheion (), is a town on the eastern shore of the Mani Peninsula, and a former municipality in Laconia, Peloponnese (region), Peloponnese, Greece. Since the 2011 local government reform it is par ...
, which was the most convenient outlet. All others involved a trek over mountains.
Post-classical Laconia
Modern Laconia is a political subdivision of Greece covering the
Evrotas Valley
The Evrotas Valley is an 82 km elongated valley between Taygetus and Parnon which traverses Laconia, Greece. Homer called the valley Kili Lakedemon, while Sparta, Mystras and Gytheio are the main cities within the valley. It is one of the larg ...
, the massifs on either side, the two headlands, and the enclosed Laconian Gulf with its coastal islands. Its seat is the city of
Sparta
Sparta was a prominent city-state in Laconia in ancient Greece. In antiquity, the city-state was known as Lacedaemon (), while the name Sparta referred to its main settlement in the Evrotas Valley, valley of Evrotas (river), Evrotas rive ...
, as in ancient times, at a site which dominated and still dominates the valley from its central position. However, the rich-soil plain is entirely divided into villages that practice
agriculture
Agriculture encompasses crop and livestock production, aquaculture, and forestry for food and non-food products. Agriculture was a key factor in the rise of sedentary human civilization, whereby farming of domesticated species created ...
,
viticulture
Viticulture (, "vine-growing"), viniculture (, "wine-growing"), or winegrowing is the cultivation and harvesting of grapes. It is a branch of the science of horticulture. While the native territory of ''Vitis vinifera'', the common grape vine ...
, and
arboriculture
Arboriculture (, from ) is the cultivation, management, and study of individual trees, shrubs, vines, and other perennial woody plants. The science of arboriculture studies how these plants grow and respond to cultural practices and to their env ...
intensely.
The main roads from Sparta form a branching network leading out radially from the city to connect other cities and towns in the valley. A web of secondary roads fills in the spaces between the main roads.
Climate
The Evrotas Valley enjoys a sunny and warm
Mediterranean climate
A Mediterranean climate ( ), also called a dry summer climate, described by Köppen and Trewartha as ''Cs'', is a temperate climate type that occurs in the lower mid-latitudes (normally 30 to 44 north and south latitude). Such climates typic ...
(
Köppen Köppen is a German surname. Notable people with the surname include:
* Bernd Köppen (1951–2014), German pianist and composer
* Carl Köppen (1833-1907), German military advisor in Meiji era Japan
* Edlef Köppen (1893–1939), German author ...
: ''Csa''). The interior of the valley records the highest summer mean maximum temperatures in
Greece
Greece, officially the Hellenic Republic, is a country in Southeast Europe. Located on the southern tip of the Balkan peninsula, it shares land borders with Albania to the northwest, North Macedonia and Bulgaria to the north, and Turkey to th ...
and is comparable to areas of
Andalusia
Andalusia ( , ; , ) is the southernmost autonomous communities of Spain, autonomous community in Peninsular Spain, located in the south of the Iberian Peninsula, in southwestern Europe. It is the most populous and the second-largest autonomou ...
in terms of summer average highs. This is due to the interior's geographical location between
Taygetus
The Taygetus, Taugetus, Taygetos or Taÿgetus () is a mountain range on the Peloponnese peninsula in Southern Greece. The highest mountain of the range is Mount Taygetus, also known as "Profitis Ilias", or "Prophet Elias" (Elijah).
The name is o ...
and
Parnon
Parnon or Parnonas () or Malevos (Μαλεβός) is a mountain range, or massif, on the east of the Laconian plain and the Evrotas Valley. It is visible from Athens above the top of the Argive mountains.
The western part is in the Laconia pre ...
mountains, completely cut out from the sea on all directions, some 30 km away from the shores. As the meltemi winds sweep Greece during the summer, both mountains provide a constant hot foehn winds effect which strongly affects the interior of the valley.
During July 2023 the Hydro Meteorological station of the
National Observatory of Athens
The National Observatory of Athens (NOA; ) is a research institute in Athens, Greece. Founded in 1842, it is the oldest List of research institutes in Greece, research foundation in Greece. The Observatory was the first scientific research insti ...
in Evrotas registered a record mean max temperature of 42.3°C. On August 3, 2021 the Evrotas station recorded 47.4°C. On average this station records 43 days annually with temperatures over 40.0°C. On July 30, 2021 the Kelefina Hydro Meteorological station of the
National Observatory of Athens
The National Observatory of Athens (NOA; ) is a research institute in Athens, Greece. Founded in 1842, it is the oldest List of research institutes in Greece, research foundation in Greece. The Observatory was the first scientific research insti ...
recorded 47.1°C.
In July 2023 the
World Meteorological Organization
The World Meteorological Organization (WMO) is a List of specialized agencies of the United Nations, specialized agency of the United Nations responsible for promoting international cooperation on atmospheric science, climatology, hydrology an ...
station in
Gytheio
Gytheio ( ) or Gythio, also the ancient Gythium or Gytheion (), is a town on the eastern shore of the Mani Peninsula, and a former municipality in Laconia, Peloponnese (region), Peloponnese, Greece. Since the 2011 local government reform it is par ...
registered 46.4°C which is the highest temperature ever recorded in the
National Observatory of Athens
The National Observatory of Athens (NOA; ) is a research institute in Athens, Greece. Founded in 1842, it is the oldest List of research institutes in Greece, research foundation in Greece. The Observatory was the first scientific research insti ...
fan aspirated stations network.
Ecology
In modern times, much of the river water is used for irrigation, with the result that the Eurotas is almost dry during the summer months. The waters of the Eurotas are used to irrigate mainly citrus crops, for which Laconia is famous. The plain of
Elos
Elos (, before 1930: Δουραλί - ''Dourali'') is a village and a former municipality in Laconia, Peloponnese, Greece. Since the 2011 local government reform it is part of the municipality Evrotas, of which it is a municipal unit. The municip ...
near the river's mouth is particularly fertile farmland.
In the winter months, the Evrotas is prone to flooding. On 24 November 2005 heavy floods damaged buildings and stranded automobiles in the streets, and harmed orchards, including the valley's famous orange and olive groves. The floods affected many villages along the valley as well as the town of Gytheio; of land was ruined.
Currently the nitrate waste from fertilizers is polluting the river, aggravated by diminished flow because of the irrigation demands on it.
Geology
Geomorphology
The Evrotas River occupies the floor of a rift valley, or ''
graben
In geology, a graben () is a depression (geology), depressed block of the Crust (geology), crust of a planet or moon, bordered by parallel normal faults.
Etymology
''Graben'' is a loan word from German language, German, meaning 'ditch' or 't ...
'', created by extensional forces acting over the Hellenic Plate in a northeast-southwest direction. The corresponding
fault-block mountain
Fault blocks are very large blocks of rock, sometimes hundreds of kilometres in extent, created by Tectonics, tectonic and localized stresses in Crust (geology), Earth's crust. Large areas of bedrock are broken up into blocks by Fault (geology) ...
s are the
Taygetus
The Taygetus, Taugetus, Taygetos or Taÿgetus () is a mountain range on the Peloponnese peninsula in Southern Greece. The highest mountain of the range is Mount Taygetus, also known as "Profitis Ilias", or "Prophet Elias" (Elijah).
The name is o ...
Massif on the west and the
Parnon
Parnon or Parnonas () or Malevos (Μαλεβός) is a mountain range, or massif, on the east of the Laconian plain and the Evrotas Valley. It is visible from Athens above the top of the Argive mountains.
The western part is in the Laconia pre ...
Massif on the east – both
limestone
Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...
ridges derived from a former sea bed. On the east side of Taygetus is the Sparta Fault, a
normal fault
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...
, which strikes in a zig-zag path along the foot of the massif and dips toward the interior of the valley. The river is on the western side. From it the scarps of the footwall of the Sparta Fault are visible at the base of Tayegetus.
Taygetus is transected by deep ravines through which tributaries flow into the Eurotas. At the foot of the massif is a zone of
scree
Scree is a collection of broken rock fragments at the base of a cliff or other steep rocky mass that has accumulated through periodic rockfall. Landforms associated with these materials are often called talus deposits.
The term ''scree'' is ap ...
. To the east of that
alluvial fan
An alluvial fan is an accumulation of sediments that fans outwards from a concentrated source of sediments, such as a narrow canyon emerging from an escarpment. They are characteristic of mountainous terrain in arid to Semi-arid climate, semiar ...
s from Taygetus cover half the valley, making it asymmetrical. On that account it is often called the Evrotas Furrow. The Evrotas flows over a flood plain and also through a shallow
aquifer
An aquifer is an underground layer of water-bearing material, consisting of permeability (Earth sciences), permeable or fractured rock, or of unconsolidated materials (gravel, sand, or silt). Aquifers vary greatly in their characteristics. The s ...
of sand and gravel 10–60 m deep, graded with the deep end downstream. The gradient of the aquifer is a steep 1–3%. The highest
hydraulic conductivity
In science and engineering, hydraulic conductivity (, in SI units of meters per second), is a property of porous materials, soils and Rock (geology), rocks, that describes the ease with which a fluid (usually water) can move through the porosity, ...
and transmissivity are near the junction of the Xerias and the Evrotas south of Sparti. To the east are older and finer sediments of alternating
clay
Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, ). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impuriti ...
and
marl
Marl is an earthy material rich in carbonate minerals, Clay minerals, clays, and silt. When Lithification, hardened into rock, this becomes marlstone. It is formed in marine or freshwater environments, often through the activities of algae.
M ...
beds, some of which are impermeable. Under the entire valley is a deep aquifer in the limestone floor, containing water permeating downward through the horsts. The Evrotas collects runoff and drains the deep aquifer on the east bank but loses water to the shallow aquifer on the west bank.
Recent geologic history
Analysis of bore holes in the valley indicate that in the
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58
Geologic analysis done in the 20th century hypothesized that the Evrotas Valley in the Late Pliocene was an inland sea over the lower and middle valley several hundred m deep at the current mouth of the river. The fault-block geology had developed earlier. During the Pleistocene the sea level dropped exposing a flat floor. Continued slippage along the Sparta Fault dropped the middle Eurotas valley further forcing the river to cut its way through the 100–250 m hills dividing the lower from the middle valley, creating Evrotas Ravine.
Notes
References
*
*
*
*
* .
Further reading
* Skoulikidis, Nikos, Elias Dimitriou, and Ioannis Karaouzas (Eds.), The Rivers of Greece: Evolution, Current Status and Perspectives. Berlin: Springer, 2018. ISBN 978-3-662-55367-1