About Osman Sagar Lake : Whether it is summer or winter, the one place that is crowded with streaming visitors is Osman Sagar, situated 20 kKms away from the city of Hyderabad, popularly known as Gandipet. This water body was formed by constructing a dam on the river Moosi in 1920 by Mir Osman Ali Khan. The twin city of Hyderabad and Secunderabad receive water supply from this lake. It is spread over an area of 46 square kilometers. The surroundings here are very pleasant and landscaped gardens with a swimming pool are added attractions.