| Alpheios Alpheus (Latinized), Alphios (Anglicized) | |
|---|---|
 Lower Alpheios | |
 Topographical map showing the Alpheios and its major tributaries. | |
| Etymology | "whitewater" (Frisk under Ἀλφός, "white") |
| Native name | Αλφειός (Greek) |
| Location | |
| Country | Greece |
| Regional units | Arcadia 60% Elis 30% Achaea 10%[1] |
| Physical characteristics | |
| Source | Alpheios |
| • location | Falaisia |
| • coordinates | 37°12′07″N 22°08′17″E / 37.202°N 22.138°E |
| • elevation | 380 m (1,250 ft) |
| Mouth | Ionian Sea |
• location | Gulf of Kyparissia |
• coordinates | 37°36′45″N 21°27′6″E / 37.61250°N 21.45167°E |
• elevation | 0 m (0 ft) |
| Length | 112 km (70 mi)[1] |
| Basin size | 3,658 km2 (1,412 sq mi)[1] |
| Basin features | |
| Tributaries | |
| • right | Lousios, Ladon, Erymanthos |
The Alpheios (Greek: Αλφειός, Ancient Greek: Ἀλφειός, Latin Alpheus), sometimes spelled Alfeiós, is the main stream of the Alpheios Valley drainage system, a dendritic type, originating on the north slopes of Mount Taygetus, located in the center of the Peloponnesus of Greece, and flowing to the northwest to the vicinity of Olympia, where it turns to the west and, after being impounded by the Flokas Dam, a hydroelectric facility, empties into the Gulf of Kyparissia of the Ionian Sea south of Pyrgos. The entrance into the gulf through agricultural land and across an unpopulated, sandy beach partially blocked by a spit is hydrologically unspectacular, with the water too shallow to be navigable by any but the smallest craft.
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, 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 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 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 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 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 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 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.