Nandi Hills, India in the context of Chikkaballapur district

Penna (originally known as Penneru, also known as Pinakini, Penneru, Penner, Pennar, Pennai) is a river of southern India. After originating from Nandi hills, it flows as two different streams, one in North and South directions. The Penna rises in the Nandi Hills in Chikkaballapur District of Karnataka state, and runs north and east through the states of Karnataka and Andhra Pradesh to empty into bay of bengal in Andhra Pradesh. It is 597 kilometres (371 mi) long, with a drainage basin covering 55,213 km: 6,937 km in Karnataka and 48,276 km in Andhra Pradesh. Along with this main stream is another stream south towards Tamil Nadu with the name Then Pennai or south Pennar which further moves towards the east to empty into the Bay of Bengal. The Penna river basin lies in the rain shadow region of Eastern Ghats and receives 500 mm average rainfall annually.

Devanahalli, also called "Devandahalli", "Dyaavandalli", Devanadoddi, and Devanapura, is a town in Bengaluru North District in the state of Karnataka in India. The town is located next to Nandi Hills and 40 kilometres (25 mi) to the north-east of Bengaluru.

Devanahalli is the site of Kempegowda International Airport. A multibillion-dollar Devanahalli Business Park with two IT Parks are coming up on nearly 400 acres (1.6 km) adjoining the airport. An Aerospace Park, Science Park and a ₹10 billion (US$120 million) Financial City are also coming up. A new satellite ring road will connect the city with Doddaballapur. Devanahalli is situated near the upcoming ₹1,500 billion (US$18 billion), 12,000-acre (49 km) BIAL IT Investment Region, to be the largest IT region in India.

The Arkavathi is an important mountain river in Karnataka, India, originating at Nandi Hills of Chikkaballapura district. It is a tributary of the Kaveri, which it joins at 34 km south of Kanakapura, Ramanagara District called Sangama in Kannada, after flowing through Ramanagara and Kanakapura. The river drains into the Chikkarayappanahalli Lake near Kanivenarayanapura. Kumudavathi and Vrishabhavathi rivers are tributaries to this river. It forms Chunchi falls near Haroshivanahalli. It joins Kavery river as a tributary near Mekedatu.

The South Pennar River (also known as Dakshina Painakini in Kannada and Thenpennai or Ponnaiyar or Pennaiyar in Tamil) is a river in India. It 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 and the industrial parks of Hosur and Chengam.

The river originates in the Nandi Hills in the Chikkaballapura district of Karnataka and flows through Tamil Nadu before emptying into the Bay of Bengal. It has a catchment area of 1,424 square miles (3,690 km) located in Karnataka and Tamil Nadu states. The small Kelavarapalli and Krishnagiri Dams were built across this river near Hosur and Krishnagiri. The largest dam on this river, Sathanur Dam with 7.3 Tmcft Gross Capacity is near Tiruvannamalai. The Moongilthuraipattu Sugar Factory is also situated on the bank of river.

The Palar (Tamil: பாலாறு pālāṟu [ˈpaːlaːɾu], literally "milk river") is a river of southern India. It rises in the Nandi Hills in Chikkaballapura district of Karnataka state, and flows 93 kilometres (58 mi) in Karnataka, 33 kilometres (21 mi) in Andhra Pradesh and 222 kilometres (138 mi) in Tamil Nadu before reaching its confluence into the Bay of Bengal at Vayalur about 75 kilometres (47 mi) south of Chennai. It flows as an underground river for a long distance only to emerge near Bethamangala town, from where, gathering water and speed, it flows eastward down the Deccan Plateau. The Towns of Bethamangala, Santhipuram, Kuppam, Mottur, Ramanaickenpet, Vaniyambadi, Ambur, Melpatti, Gudiyatham, Pallikonda, Anpoondi, Melmonavoor, Vellore, Katpadi, Melvisharam, Arcot, Ranipet, Walajapet, Kanchipuram, Walajabad, Chengalpattu, Kalpakkam, and Lattur are located on the banks of the Palar River. Of the seven tributaries, the chief tributary is the Cheyyar River.

Palar river water from Palar anicut is diverted to the Poondi reservoir located in the Kosasthalaiyar River basin and to Chembarambakkam Lake located in the Adayar River basin. These two reservoirs are major water supply points to Chennai city. After commissioning of the Telugu Ganga project to supply nearly 1,000,000,000 litres (260,000,000 US gal) per day of Krishna River water to the Chennai city, the dependence on Palar river water has reduced drastically.