Deriner Dam: Turkey's Tallest Dam in the Eastern Black Sea Mountains

**Deriner Dam** on the Çoruh River in Artvin Province, northeastern Turkey, is the tallest dam in Turkey at **249 meters** and among the tallest arch dams in the world. Completed in **2012** after over a decade of construction, the double-curvature arch dam generates **670 MW** of hydroelectric power in one of the most scenic and geologically challenging environments for dam building.

Introduction

The Çoruh River valley in the eastern Black Sea mountains is one of the steepest, wettest, and most biologically diverse landscapes in Turkey. The valley's precipitous terrain and abundant rainfall make it ideal for hydroelectric development but extremely difficult for construction, with access roads requiring dozens of tunnels cut through near-vertical mountainsides.

Engineering & Structure

• Type: Double-curvature arch dam
• Height: 249 meters
• Crest Length: 720 meters
• Concrete Volume: 3.26 million m³

Deriner Dam's arch rises 249 meters from its foundation in the narrow Çoruh gorge, making it the fifth-tallest dam in the world. The double-curvature arch spans 720 meters across a V-shaped valley of volcanic and metamorphic rock. The dam contains 3.26 million cubic meters of concrete and was Turkey's most technically challenging dam construction project.

The underground powerhouse houses four 167.5 MW Francis turbines. Construction began in 1998 but took 14 years due to the extreme terrain, difficult rock conditions, and frequent landslides. Workers had to stabilize the canyon walls with extensive rock anchoring before pouring concrete, and the site was accessible only through tunnels for much of the construction period.

Geographic Setting

• River: Çoruh River
• Location: Artvin Province, northeastern Turkey
• Coordinates: 41.18°N, 41.72°E
• Reservoir Length: ~42 km

The Çoruh River originates near Bayburt in northeastern Turkey and flows 431 kilometers through steep mountain gorges before crossing into Georgia and reaching the Black Sea at Batumi. It is considered one of the fastest-flowing rivers in the world, dropping approximately 3,000 meters in elevation over its course. The dam site sits in a spectacular gorge where the valley walls rise over 1,000 meters above the river.

The surrounding landscape is eastern Black Sea montane forest — a globally significant biodiversity hotspot with temperate rainforests of beech, spruce, and fir blanketing the steep mountain slopes. The region receives over 2,000 millimeters of rainfall annually, making it one of the wettest parts of Turkey. The combination of steep terrain, heavy rainfall, and unstable geology creates frequent landslides that challenged both the dam's construction and the roads leading to it.

Hydroelectric Power

• Installed Capacity: 670 MW
• Annual Output: ~2.1 TWh
• Turbines: 4 × 167.5 MW Francis turbines
• River Cascade: Part of Çoruh River cascade of multiple dams

Deriner's 670 MW capacity generates approximately 2.1 terawatt-hours of electricity per year, fed by the Çoruh's substantial year-round flow. The dam is part of a cascade of multiple dams being developed along the Çoruh River, which together aim to exploit the river's steep gradient and high rainfall for maximum hydroelectric output.

Turkey has aggressively developed its hydroelectric potential over the past two decades, and the Çoruh cascade is one of the most ambitious programs. However, the Çoruh's steep, narrow valley limits reservoir storage, meaning the dams operate largely as run-of-river facilities, with limited ability to store water between seasons.

Environmental & Social Impact

• Communities Affected: Several villages relocated or isolated
• Biodiversity: Globally important temperate rainforest ecosystem
• Landscape Change: Dramatic alteration of one of Turkey's most scenic valleys

The Çoruh Valley was considered one of the most beautiful and ecologically significant river valleys in Turkey before the cascade of dams transformed it. The reservoir behind Deriner Dam inundated portions of the valley floor, including agricultural land, hazelnut orchards, and several small villages. Some communities were relocated, while others were isolated by the rising water and the road infrastructure changes.

Environmentalists have raised concerns about the cumulative impact of multiple dams on the Çoruh's ecosystem. The river supported populations of Caspian trout and other species adapted to fast-flowing, cold water. The series of reservoirs has converted much of the free-flowing river into still water, fundamentally altering the aquatic habitat. The surrounding temperate rainforests, part of the Caucasus biodiversity hotspot, are among the most species-rich non-tropical forests in the world.

Key Facts

• Deriner Dam is the tallest dam in Turkey at 249 meters.
• It is one of the highest arch dams in the world.
• The Çoruh River is considered one of the world's fastest-flowing rivers.
• Construction took 14 years due to extreme terrain and geological challenges.
• The eastern Black Sea mountains where it sits are a global biodiversity hotspot.

Fun Facts

• The Çoruh Valley is a world-renowned whitewater kayaking destination, and dam construction has eliminated some of its most famous rapids.
• Artvin Province, where the dam is located, has the lowest population density of any province in Turkey despite receiving some of the country's heaviest rainfall.
• The road to the dam site passes through so many tunnels that drivers spend more time underground than in daylight on the approach.

Final Thoughts

Deriner Dam is an extraordinary engineering achievement in one of the most challenging construction environments imaginable. Its soaring arch in the dramatic Çoruh gorge is a testament to modern dam-building technology, even as the cascade it anchors continues to transform — and diminish — one of Turkey's most spectacular river valleys.