Valens Aqueduct

Valens Aqueduct
Valens Aqueduct at Atatürk Bulvari seen from southwest
Carries	Aqueduct to Constantinople
Locale	Istanbul, Turkey
Official name	Bozdoğan Kemeri
Characteristics
Design	Arch bridge
Material	Stone, brick
Total length	Originally 971 m (3,186 ft)
Width	7.75–8.24 m (25.4–27.0 ft)
Height	Ca. 29 m (95 ft)
Longest span	Ca. 4 m (13 ft)
History
Construction end	368 AD

The Valens Aqueduct (Turkish: Valens Su Kemeri or Turkish: Bozdoğan Kemeri, meaning "Aqueduct of the Grey Falcon"; Ancient Greek: Ἀγωγὸς τοῦ ὕδατος, Agōgós tou hýdatos, meaning simply "aqueduct") is a Roman aqueduct which was the major water-providing system of the Eastern Roman capital of Constantinople (modern Istanbul, Turkey). Completed by Roman Emperor Valens in the late 4th century AD, it was maintained and used by the Byzantines and later the Ottomans, and remains one of the most important landmarks of the city.

The most visible bridge section of 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.

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 kilometres (160 mi) 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 combined capacity of over 1 million cubic meters.