Goliam Beglik is a captivating reservoir nestled in the lands of Batak, situated in the Western Rhodopes. It forms a vital segment of the Batak Hydroelectric Cascade.
Construction and Location
The reservoir was ingeniously constructed along the winding Kriva River, a tributary of the Devin River, in the picturesque locale of “Tashboaz” (also known as “Stone Passage”). The dam wall itself proudly stands on the Republican Road II-37, strategically placed halfway between Dospat and Batak, with Sarnitsa lying a bit closer to its shores. Nearby, the “Beglika” reserve offers a natural haven.
Historical Background
Construction of this engineering marvel commenced in 1946. Initially, its primary purpose was to serve as an annual equalizer for the Vacha Hydro Power Plant and to facilitate irrigation in the Krichim area. However, it later found its place as an annual equalizer in the newly designed Batak Hydroelectric Cascade. Partial filling of the reservoir began in 1949, with official operations kicking off on November 11, 1951.
Architectural Features
The dam wall was originally built using rhyolite blocks, arranged in a meticulous stone masonry. The airside slope was lined with a one-meter thick stone masonry, while the waterside featured a robust 2.5-meter concrete screen, complete with hydro insulation and concrete slabs. The wall’s unique design boasts a horizontal curve with a radius of 2100 meters and an arc height of 3 meters. From its base, the wall rises to a height of 46.50 meters, with the crown perched at an altitude of 1528.5 meters, stretching 191 meters in length.
Spillway and Main Outlets
To the right of the wall lies the trench spillway, measuring 57 meters in length and capable of handling 58 cubic meters per second. The main outlet, integrated into the wall, includes two pipes with a diameter of 1200 mm, offering a discharge capacity of 36 cubic meters per second.
Mid-20th Century Challenges
In the mid-1960s, the reservoir faced a formidable challenge when the dam wall experienced significant deformation. The upper section shifted 68 centimeters horizontally and 77 centimeters vertically, compromising the waterproof screen and leading to water filtration at a rate of 190 liters per second. Consequently, the reservoir was drained for extensive repairs. A brand-new screen was installed, the dam body was injected with a cement-sand mixture, and the upper sections were re-masoned. The repair also included an upgrade to the spillway, enhancing the reservoir’s useful volume by 3 million cubic meters.
This intricate blend of engineering, history, and natural beauty makes Goliam Beglik Reservoir a fascinating subject of study and admiration.
