Kardzhali Dam in the context of "Arda (Maritsa tributary)"

The Arda (Bulgarian: Арда [ˈardɐ], Greek: Άρδας [ˈarðas], Turkish: Arda [ˈaɾda]) is a 290-kilometre-long (180 mi) river in Bulgaria and Greece. It is a tributary of the Maritsa (or Evros). Its source lies in the Bulgarian Rhodope Mountains near the village Arda, part of the municipality of Smolyan. It flows eastward past Rudozem, Kardzhali and Ivaylovgrad and enters Greece in the northern part of the Evros regional unit. It flows into the Maritsa on the border of Greece and Turkey, between the Greek village Kastanies and the Turkish city Edirne. In the Bulgarian section, there are three hydroelectric and irrigation dams, Kardzhali Dam, Studen Kladenets and Ivaylovgrad Dam. The Bulgarian section is 229 kilometres (142 mi) long, making the Arda the longest river in the Rhodopes. The medieval Dyavolski most arch bridge crosses the river 10 kilometres (6 mi) from Ardino.

The three floods of February 18, 2005, when the water level was at 4.8 metres (16 ft), March 1 and March 7, 2005, flooded the low-lying areas, especially the Kastanies area which turned into a lagoon. The merging of the waters of the Maritsa (Evros/Meriç) caused streets and buildings including homes to be flooded, leaving people stranded in their homes.

The Studen Kladenets Reservoir (Bulgarian: язовир „Студен кладенец“, meaning "cold well") is the third largest reservoir by volume in Bulgaria after Iskar Dam and Kardzhali Dam. It is situated on the river Arda, and is created behind the Studen Kladenets dam, 30 km south-east of the town of Kardzhali. There are another two dams of the Arda - Kardzhali Dam to the west (upstream) and Ivaylovgrad Dam to the east (downstream). The dam is operated by the Bulgarian National Electric Company, NEK EAD.

The reservoir has a total volume of 388 million m and a drainage basin of 3,706 km and is 29 km long. It is situated at an average 227 m above sea level, its dam being 338 m long and 67.5 m high. The top of the dam consists of nine spillways, each one being 10.5 by 5 m."Studen Kladenets" Hydroelectric Power Plant is situated appr. 1 km downstream of the dam. Initially the HPP had four Francis-type turbines, 15 MW each. А project for reconstruction and upgrading the HPP with another 16 MW turbine and a smaller eco-turbine underwent and after the completion, the total output reached 85 MW with annual production of 165 GWh of electricity.

The Ivaylovgrad Dam(язовир "Ивайловград") is located in the eastern Rhodope Mountains and is situated on the Arda river, Southern Bulgaria. There are another two large dams of the Arda upstream - Kardzhali Dam and Studen Kladenets Dam to the west of Ivaylovgrad Dam.

The dam creates Ivaylovgrad reservoir, which has a total volume of 157,000,000 m (127,000 acre⋅ft) and a drainage basin of 5,128 km (1,980 sq mi). It is situated at an average 120 m above sea level, its dam being 250 m (820 ft) long and 73 m (240 ft) high. The top of the dam consists of six spillways, totaling 83.5 m (274 ft) m in length.