Golyam Beglik, Mountain reservoir in Rhodope Mountains, Bulgaria.

Golyam Beglik is a reservoir on the Kriva River in the Western Rhodopes, part of the Batak hydropower cascade. Its stone dam, faced with rhyolite blocks, stands 46.5 m high and 191 m long on the Batak–Dospat road. The water covers 4.1 km², the largest area of the Batak reservoirs, and is fed by the Cherno Dere and Zhalto Dere streams.

Construction began in 1946, first intended as a yearly equaliser for the Vacha hydroelectric plant and for irrigation near Krichim, then folded into the Batak hydropower cascade. Partial filling started in 1949 and the reservoir entered service on 11 November 1951. It was called Tashboaz until 14 March 1950 and Vasil Kolarov until 11 June 1999. In the mid-1960s the dam deformed by 68 cm horizontally and 77 cm vertically, leaking 190 l/s; it was emptied, re-faced and grouted, and the spillway was raised, adding 3 million m³.

The reservoir was officially named Vasil Kolarov until 1999, after the communist leader; locals still recall the older name Tashboaz, meaning "stone pass". On its western shore stands Chatama, a bungalow complex run by the Bikearea organisation, which holds summer camps and guided trekking and biking tours in the surrounding mountains.

The dam wall stands on Republican Road II-37, roughly midway between Dospat and Batak, with Sarnitsa somewhat closer. The reservoir lies at 1,450–1,560 m altitude, so access is by this mountain road. At Chatama on the western shore there is a bungalow complex with accommodation and a Bikearea base for summer camps, trekking and biking.

The reservoir was officially named Vasil Kolarov from 1950 until 11 June 1999, after the communist leader; the older name of the site was Tashboaz, "stone pass". The dam is a stone-walled structure faced with rhyolite blocks, 46.5 m high, with a 191 m crest at 1528.5 m elevation.