Düden Waterfalls are a group of waterfalls in the province of Antalya, Turkey. The waterfalls, formed by the recycle station water, are located 12 kilometres (7.5 mi) north-east of Antalya. They end where the waters of the Lower Düden Falls drop off a rocky cliff directly into the Mediterranean Sea.
At the 28th and 30th kilometre markers (17 and 19 miles) of the old route from Antalya-Burdur (which goes through Döşemealtı town), two big karstic sources appear. These sources, Kırkgözler and Pınarbaşı, merge after a short flow and disappear into Bıyıklı Sinkhole. Some of the sinkholes can swallow a river or lake. In this region, the Suğla (Konya) big sinkhole and the Bıyıklı sinkhole output 30 cubic metres per second (1,100 cu ft/s). This quantity is the output of Kırkgöz and Pınarbaşı springs at inundation.
The water, which disappears at Bıyıklı Sinkhole, travels 14 km (9 mi) underground and comes out again at Varsak pit. After a very short fall, it disappears again from the other end. The water which disappears at Varsak goes underground for 2 km (1.2 mi) and comes out again at Düdenbasi, by pressure made by a syphon. The water which falls from Düdenbasi is the water coming from Kepez Hydroelectrical Complex.
A regulator built in front of the Bıyıklı Sinkhole directs the waters of Kırkgözler and Pınarbaşı into a canal to the Kepez Hydroelectric Plant, where a pressure pipe carries it to a balancing funnel and drops it over the plant's turbines.
The water from the plant's discharge unit is brought to Düdenbaşı again by a long canal, where it forms artificial cascades. From there the amount of water is that of a large river. Seven irrigation trenches distribute the water to land north-east of Antalya.
After Düdenbasi, the waters of Düdençay separate into a number of streams and finally, east of Antalya, cascade 40 metres (131 ft) from a platform into the Mediterranean. A park surrounds these waterfalls. They can be seen from the sea by taking a boat trip from Antalya yacht harbour.