🏗️ Blog · 4 min read
The Oymapınar Dam: the Wall That Made the Green Canyon
Quick answer
The emerald lake exists because of a 185-metre concrete arch. Its story is better than most guidebooks bother to tell.
Every photograph of the Green Canyon is secretly a photograph of a dam. The emerald lake exists because of the Oymapınar Dam — one of Turkey's great engineering works, and a story most excursion sellers skip entirely.
The numbers that matter
A double-curvature concrete arch about 185 metres tall, built between 1977 and 1984 across the Manavgat river's gorge. Behind it: roughly 300 million cubic metres of water over about 4.7 square kilometres — the lake you cruise. Its four turbines sit in an underground powerhouse, invisible from the boats, which is why the canyon feels wild despite the engineering holding it up.
What the water drowned
The reservoir swallowed Dumanlı — a karst spring once proposed in the scientific literature as the largest of its kind in the world, the spring that fed ancient Side's aqueduct. It now lies about 120 metres beneath the surface, still flowing into the lake from below. Roughly forty arches of that Roman aqueduct still stand near the dam.
Why this matters on your cruise
The dam explains everything you see: why the water is deep and still, why the colour glows (spring water filtered through limestone), and why swimming feels cool all summer (those springs never warm). The wall itself is the day's most underrated sight — best appreciated from the water, where its scale finally registers.