Antalya Duden Waterfalls, also known as Iskender Waterfall or Upper Duden Waterfall, is situated in the Varsak Neighborhood, within the boundaries of Kepez District. Some locals refer to it as Düdenbaşı Waterfall. On the old Antalya-Burdur road, at the 28th-kilometer mark, there are two large karst springs called Pinarbasi, and at the 30th-kilometer mark, there are two rivers with abundant water supply that merge and disappear into Bıyıklı Sinkhole. The water that vanishes in the Bıyıklı Sinkhole re-emerges after 14 kilometers of underground flow at one end of the Varsak Depression and disappears again at the other end after a short flow. The water lost in Varsak rises to the surface at Düdenbaşı after two kilometers of underground flow.
Even on days when no visible water flows from the surface, at least 10 cubic meters of water per second rises to the surface under the Düdenbaşı Waterfall. The maximum flow rate of this water is 94 cubic meters, while the average is 15-16 cubic meters per second.
The water cascading from above in Düdenbaşı is water from the Kepez hydroelectric power plant. After Düdenbaşı, the Düden Stream is divided into two main channels at the Koyunlar regulator, and after 9 kilometers, it flows into the Mediterranean Sea with a waterfall from a 40-meter-high travertine threshold in the east of Antalya.
Source: “Düden Şelalesi” Dünden Bugüne Antalya [I. Cilt], Antalya İl Kültür ve Turizm Müdürlüğü (2012)