The South Pennar River is a river in India. Bangalore, Hosur, Krishnagiri,Kaveripattinam, and Cuddalore are the important cities on the banks of South Pennar river. This is the second longest river in Tamil Nadu, with a length of 497 km, after the Kaveri. Chandapura, Anekal, Hosur, Bagalur, and Chengam are the major industrial settlements on its banks. The river is severely polluted by industrial waste as it flows through major industrial areas in the eastern suburbs of Bangalore, Industrial parks of Hosur and Chengam.

Bellandur Lake is located in the suburb of Bellandur in the southeast of the city of Bengaluru. It is the largest lake in the city. It is a part of Bellandur drainage system that drains the southern and the south-eastern parts of the city. The lake is a receptor from three chains of lakes upstream, and has a catchment area of about 148 square kilometres. Water from this lake flows further east to the Varthur Lake, from where it flows down the plateau and eventually into the Pinakani river basin.