Saturday, December 17, 2016


Saraçhane, Fatih - Istanbul - Turkey

GPS : 41°00'58.0"N 28°57'19.0"E / 41.016111, 28.955278

 photo bozdogan_aqueduct119.jpg


The Valens Aqueduct (Turkish: Bozdoğan Kemeri, meaning "Aqueduct of the grey falcon"  was the major water-providing system of medieval Constantinople (modern Istanbul, in Turkey). Being the oldest aqueduct in Istanbul, Valens has served the city for more than 15 centuries as its most important water source. Restored by several Ottoman Sultans, it is one of the most important landmarks of the city.

The aqueduct stands in Istanbul, in the quarter of Fatih, and spans the valley between the hills occupied today by the Istanbul University and the Fatih Mosque. The surviving section is 921 metres long, about 50 metres less than the original length. The Atatürk Bulvarı boulevard passes under its arches.

Although the exact date of its construction has been lost in history, the Valens Aqueduct, also known as the Hadrianus Aqueduct, is a legacy of the Late Roman and Early Byzantine era. Over the centuries, the structure fell into disrepair and eventually to ruins, until the conquest of the city, when it was restored in order to deploy its original function: namely, to distribute water in periods of regional shortage.

It is believed that when first constructed, the aqueduct was more than 1 kilometer in length. Over the years, additions have been made, although the point at which the structure was given its Turkish name "Bozdoğan" is unknown.

Istanbul, an important city in almost every era, the water problem that could only be solved with great ingenuity and inventive projects. Aqueducts and cisterns remaining from the Roman period are the proof of engineering and architectural wonders. The water was carried and distributed to the city, which was some 20 kilometers away, from the Belgrade Forest with these unique installations.

Valens Aqueduct, called Bozdoğan Kemeri, is one of the wonders of ancient architecture and engineering among these splendid aqueducts and adds an interesting line to the silhouette of the city. It was constructed by Emperor Valens in AD 368 as part of the new water supply system for the city. Although it was 1000 meters long only 920 meters of it remains today and it appears much lower than in the Byzantine time, since the surrounding ground level has risen 6 meters. It connects the two hills of the city, Beyazıt Kulesi (Beyazıt Tower) and Fatih Camii (Fatih Mosque), and is 60 meters high and has 2 story arches.

It ends at a monumental fountain in the vicinity of the Forum of Theodosius (Tauri) located between Süleymaniye and Beyazıt Mosques . Water was distributed to various districts from there. The pool unfortunately disappeared without leaving a trace. The aqueduct encurred repairs during Byzantine period, however the traces of repairs seen today are of Ottoman Period due to the earthquake damages. The second floor of the aqueduct facing Şehzadebaşı Mosque was torn down since it hindered the view of the mosque.

The Aqueduct of Valens had a length of 971 meters and a maximum height of ca. 29 meters (63 meters above sea level) with a constant slope of 1:1000. Arches 1-40 and 46-51 belong to the time of Valens, arches 41-45 to Sultan Mustafa II, and those between 52 and 56 to Sultan Süleyman I. Arches 18-73 have a double order, the others a single order.

Originally the structure ran perfectly straight, but during the construction of the Fatih Mosque - for unknown reasons - it was bent in that section. The masonry is not regular, and uses a combination of ashlar blocks and bricks. The first row of arches is built with well-squared stone blocks, the upper row is built with four to seven courses of stones alternated with a bed of smaller material (opus caementitium) clamped with iron cramps. The width of the aqueduct varies from 7.75 meters to 8.24 meters. The pillars are 3.70 meters thick, and the arches of the lower order are four meters wide.

The water comes from two lines from the northeast and one coming from the northwest, which join together outside the walls, near the Adrianople Gate (Edirne Kapı). Near the east end of the aqueduct there is a distribution plant, and another lies near Hagia Sophia. The water feeds the zone of the imperial palace. The daily discharge in the 1950s amounted to 6,120 cubic meters. During Byzantine times, two roads important for the topography of medieval Constantinople crossed under the eastern section of the aqueduct.

The construction of a water supply system for the city (then still called Byzantium) had begun already under the Roman emperor Hadrian. Under Constantine I, when the city was rebuilt and increased in size, the system needed to be greatly expanded to meet the needs of the rapidly growing population.

The Valens aqueduct, which originally got its water from the slopes of the hills between Kağıthane and the Sea of Marmara, was merely one of the terminal points of this new wide system of aqueducts and canals - which eventually reached over 250 kilometers in total length, the longest such system of Antiquity - that stretched throughout the hill-country of Thrace and provided the capital with water. Once in the city, the water was stored in three open reservoirs and over a hundred underground cisterns, such as the Basilica Cistern, with a total capacity of over 1 million cubic meters.

The exact date that construction on the aqueduct began is uncertain, but it was completed in the year 368 during the reign of Roman Emperor Valens, whose name it bears. It lay along the valley between the third and fourth hills of Constantinople, occupied respectively at that time by the Capitolium and the Church of the Holy Apostles. According to tradition, the aqueduct was built using the stones of the walls of Chalcedon, pulled down as punishment in 366 after the revolt of Procopius.

The structure was inaugurated in the year 373 by the urban prefect Clearchus, who commissioned a Nymphaeum Maius in the Forum of Theodosius, that was supplied with water from the aqueduct. After a severe drought in 382, Theodosius I built a new line (the Aquaeductus Theodosiacus), which took water from the northeastern region known today as the “Belgrade Forest”.

Other works were executed under Theodosius II, who decided to distribute the water of the aqueduct exclusively to the Nymphaeum, the Baths of Zeuxippus and the Great Palace of Constantinople. The aqueduct, possibly damaged by an earthquake, was restored under Emperor Justinian I, who connected it with the Cistern of the Basilica of Ill (identified today either with the Yerebatan or with the Binbirdirek (Turkish: "thousand and one columns") cistern, and was repaired in 576 by Justin II, who built a separate pipe.

The aqueduct was cut by the Avars during the siege of 626, and the water supply was reestablished only after the great drought of 758 by Emperor Constantine V. The Emperor had the whole water supply system repaired by a certain Patrikios, who used a large labour force coming from the whole of Greece and Anatolia. Other maintenance works were accomplished under Emperors Basil II (in 1019) and Romanos III Argyros.

The last Byzantine Emperor who took care of the aqueduct was Andronikos I Komnenos. Neither during the Latin Empire nor during the Palaiologan period were any repair works executed, but by that time the population of the city had shrunk to about 40,000 - 50,000 inhabitants, so that the water supply was no longer a very important issue. Nevertheless, according to Ruy Gonzáles de Clavijo, a Castilian diplomat who traveled to Constantinople en route to an embassy to Timur in 1403, the aqueduct was still functioning.

After the Fall of Constantinople (1453), Sultan Mehmet II repaired the whole water supply, which was then used to bring water to the imperial palaces of Eski Sarayi (the first palace, built on the third hill) and Topkapı Sarayi, and connected it with a new line coming from the northeast.

The great earthquake of 1509 destroyed the arches near the Mosque of Şehzade, which was erected some time later. This gave rise to the popular legend that they were cut, in order to allow a better view from the nearby mosque. The repairs to the water-supplying net continued under Beyazid II, who added a new line.

Around the middle of the 16th century, Suleyman I rebuilt arches (now ogival) 47 up to 51 (counted from the west) near the Şehzade Mosque, and commissioned the Imperial Architect Mimar Sinan to add two more lines, coming from the Forest of Belgrade (Belgrad Ormanı). The increased flow allowed the distribution of water to the Kιrkçeşme ("Forty Fountains") quarter, situated along the aqueduct on the Golden Horn side, and so called after the many fountains built there under Suleyman.

Under Sultan Mustafa II, five arches (41-45) were restored, respecting the ancient form. An inscription in situ, dated 1696/97, commemorates the event. His successor Ahmed III repaired again the distribution net.

In 1912, a 50-meter-long part of the aqueduct near the Fatih Mosque was pulled down. In the same period, a new modern Taksim ("distribution plant", lit. 'division') at the east end was erected.

Today you can drive or walk under the arches of the Valens Aqueduct located on Atatürk Caddesi between Unkapanı and Aksaray, close to İMÇ (İstanbul Home Textile Market). The preponderance of the once sprawling aqueduct has largely been destroyed, with the notable exception of the remains found on the Saraçhane Atatürk Boulevard. In 1988, the Municipality of Istanbul decided to restore this piece of history, which also bears witness to Ottoman design.


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