Lake Durusu (also called Lake Terkos or Targus) is a lake in Thrace region of Turkey. It would be eliminated by the planned Istanbul Canal.
The lake lies in İstanbul Province. It is situated to the north west of Istanbul and its distance to the city is 40 kilometres (25 mi). Its elevation with respect to sea level is about 4.5 metres and its maximum depth is 11 metres. The surface area is 39 square kilometres. Depending on the rainfall, this lake with a 162 million m3 of the water potential satisfies approximately 20% of the water needs of Istanbul and surrounding settlements..
Lake Durusu was originally a lagoon and it is separated from the Black Sea coast by a 700 metres. wide strip. Currently there is no connection to the sea and it is a fresh water lake fed by a number of creeks the most important one being the Istrance creek. The drainage basin is 619 square kilometres.
The annual water supply capacity of the lake is 162×106 cubic metres.
