The lake is around 46 km2, and the reservoir is around 29 km2, with total level of 1,790 feet and a capacity of 3.9 tmc ft.[1] Osman Sagar was created by damming the Musi River in 1920, to provide an additional source of drinking water for Hyderabad and to protect the city after the Great Musi Flood of 1908.

A princely guest house called Sagar Mahal, overlooking the lake and now a heritage building, was built as a summer resort of the last Nizam.

When the Nizam consulted Sri Sir M.Visheswaraya regarding the twin problems of heavy floods in monsoon and acute shortage of water during summer, the latter designed a plan for construction of a Dam which needed high engineering skills in those days.

[2] Himayat Ali Mirza, great-grandson of Nizam VII has recently joined the “save Osmansagar and Himayatsagar” campaign for saving the twin reservoirs and has also urged the of Telangana CM to scrap the orders of GO 111.

Scrapping of GO 111 has led to increasing the construction and concretisation activities near the lakes, ultimately resulting in consequent flooding.