Harbour informations about: Channel

Within the North Bay there are two rocky islands that provide protection to the bay and also were used as components of the Phoenician harbor. They are separated by a gap of about 20 m and 2-3 m deep. The seafloor of this gap revealed no evidence of any stones construction to indicate that it had been closed or a bridge had connected these islands at any time. Nevertheless, when the harbor was constructed and functioning, presumably the gap was narrower and no sailing craft could pass through. In ancient times this gap probably provided a good washing channel to scour out the accumulated sediments from the harbor basin. This channel being under the constant waves energy widened during the centuries (2500 years passed), by the erosion of the kurkar bedrock. Nowadays, the gap is wide enough to cause trouble waters within the harbor basin in stormy periods.




Atlit


With the completion of the quays, the harbor basin was enclosed and well sheltered from the surge. Within this enclosed basin was a setting body of still water, a terminal for the shifting sand and also a reason for gradual silting. In order to prevent or minimize such a natural process flushing currents were created, flowing out through the harbor mouth. Such a flush current was created by an inflow through a series of shallow channels transversely crossing over the southern mole. Each channel had its opening facing the surge with a base above the income waves to create a constant inflow of water. Such channels would feed the harbor basin with additional water. Vertical grooves for insertion of sluice gates would enable proper control over the rate of the inflow in various sea conditions. The additional quantity of water would find a way out through the harbor channel, flushing it properly. Confirmation for the successful flushing of the harbor basin was found on the sea floor. Within the main basin, under layers of wave carried deposits there was a thin layer of fine mud with some 1st century pottery shards on it. Such sediment is typical of still waters and represents the time when Sebastos was fully operational. The absence of sandy particles in the mud indicates that there was no silting of the harbor from the open sea. Probes carried outside the harbor mouth revealed a deposit of over two meters thick of mud, dirt and all sorts of garbage from the harbor, some kind of dumping site for whatever was carried away by that overflowing flushing currents.




Caesarea


On the southwestern edge of the rocky promontory a channel was carved in the rock, leveled at 20 to 30 cm above the sea level. The sides of the channel have vertical grooves in which wooden gates could be placed to control the water flow into the channel. From plans drawn by researchers of the Palestine Exploration Fund in the 19th century, it seems that there were other channels east to this one. Their function was to force a surplus of water into the harbor and thus, create a constant flow from the entrance channel onward. This flow would ensure the removal of sediments from the bottom of the harbor, to prevent sand and silt from penetrating through the entrance. Proof that such a flow existed was found in a layer more than 1 m thick at the mouth of the harbor. The layer contained muddy clay and an abundance of pottery, metal parts of ships and gravel that drifted there from the bottom of then-active harbor.

Other remains of the Herodian construction on the southern side of the Middle Basin are today covered by structures of the Crusader harbor fortress and the concrete of the modern wharf.




Caesarea


Mit dem Meer ist dieses Bauwerk durch einen geknickten, ca.23.50m langen Kanal verbunden. Dieser trifft die eine Breitseite des Beckens nicht mittig und verjüngt sich kurz vor dem Erreichen der Beckenwand. Die unterste Blockreihe aus Sandstein springt vor und bildet hier somit auch einen Absatz. Der Kanalboden, nicht so tief wie das Becken (ca. 1.75 m), ist mit Blöcken ausgelegt. Mittig verläuft eine vertieft angelegte Rinne mit konkavem Querschnitt (B 0.54m x T 0,13m), zu der sich die beiden flankierenden Bodenhälften hin leicht neigen. Zwei Dreieckssteine im SO und SW Winkel engen den Durchgang weiterhin ein.



0 Die gesamte Anlage scheint zwei Bauphasen aufzuweisen (s.u.). Der Kanal weist an der engsten Stelle eine konische Verjüngung auf durch zwei strebepfeilerähnliche Konstruktionen. Auch das getreppte Mauerprofil erinnert an heutige Trockendocks, dennoch konnte eine Verschlussvorrichtung des Kanals nicht nachgewiesen werden.




Mozia



Grazie all’aerofotografia è possibile individuare una lunga e sinuosa traccia scura che, partendo dalla testata del molo destro e connettendosi al bacino esagonale traianeo, aveva funzione di canale d’ingresso a quest’ultimo bacino.


Ostia-Claudio


Un sistema di canali (tra cui la Fossa Traiana, l’odierno canale di Fiumicino), collegavano il porto con il Tevere e quindi con la capitale. La via Portuense, inoltre, assicurava il collegamento via terra.
Un’altra strada, chiamata più tardi via Flavia-Severiana, collegava il porto di Traiano ad Ostia. Essa attraversava l’Isola Sacra, ovvero il territorio compreso tra il braccio naturale del Tevere, a sud, e la Fossa Traiana, a nord.


Ostia-Traiano


Il canale d’ingresso al bacino esagonale è largo in media 60 metri ed è lungo oltre 500 metri. Esso era fiancheggiato a sinistra da un grande molo e dalle banchine antistanti ai magazzini cd. severiani e a destra dalle banchine dei magazzini traianei.


Ostia-Traiano



Un canale si distaccava dal lato meridionale del canale d’ingresso al bacino esagonale collegando il porto di Traiano con la Fossa Traianea. Questo canale, oggi totalmente interrato, è lungo 330 metri ed è largo 25 metri.


Ostia-Traiano


La Fossa Traiana è un canale artificiale, largo 50 metri, che fiancheggiava a sud il porto di Traiano collegandolo direttamente al Tevere. Oggigiorno essa è nota quale canale di Fiumicino.


Ostia-Traiano


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