<P> According to 2011 report of the Food and Agriculture Organization of the United Nations, India's basin wise distribution of catchment area and utilizable surface water resources is presented in the following table: </P> <Table> <Tr> <Th> (hide) Basin number </Th> <Th> River basin unit </Th> <Th> Region </Th> <Th> Draining into </Th> <Th> Catchment area (% of river irrigated India) </Th> <Th> Average runoff (km) </Th> <Th> Additional available surface water (km) </Th> </Tr> <Tr> <Td> 1.1 </Td> <Td> Ganges (GBM) </Td> <Td> North </Td> <Td> Bangladesh </Td> <Td> 26.5 </Td> <Td> 525.02 </Td> <Td> 250 </Td> </Tr> <Tr> <Td> </Td> <Td> Brahmaputra (GBM) </Td> <Td> Northeast </Td> <Td> Bangladesh </Td> <Td> 6 </Td> <Td> 537.24 </Td> <Td> 24 </Td> </Tr> <Tr> <Td> 1.3 </Td> <Td> Meghna / Barak (GBM) </Td> <Td> East </Td> <Td> Bangladesh </Td> <Td> 1.5 </Td> <Td> 48.36 </Td> <Td> </Td> </Tr> <Tr> <Td> </Td> <Td> Other Northeast rivers </Td> <Td> Northeast </Td> <Td> Myanmar, Bangladesh </Td> <Td> 1.1 </Td> <Td> 31 </Td> <Td> </Td> </Tr> <Tr> <Td> </Td> <Td> Subernarekha </Td> <Td> East - southeast </Td> <Td> Bay of Bengal </Td> <Td> 0.9 </Td> <Td> 12.37 </Td> <Td> </Td> </Tr> <Tr> <Td> </Td> <Td> Brahmani - Baitarani </Td> <Td> East - southeast </Td> <Td> Bay of Bengal </Td> <Td> 1.6 </Td> <Td> 28.48 </Td> <Td> 6.8 </Td> </Tr> <Tr> <Td> 5 </Td> <Td> Mahanadi </Td> <Td> Central - east </Td> <Td> Bay of Bengal </Td> <Td> 4.4 </Td> <Td> 66.88 </Td> <Td> 18.3 </Td> </Tr> <Tr> <Td> 6 </Td> <Td> Godavari </Td> <Td> Central </Td> <Td> Bay of Bengal </Td> <Td> 9.7 </Td> <Td> 110.54 </Td> <Td> 50 </Td> </Tr> <Tr> <Td> 7 </Td> <Td> Krishna </Td> <Td> Central </Td> <Td> Bay of Bengal </Td> <Td> 8 </Td> <Td> 78.12 </Td> <Td> 76.3 </Td> </Tr> <Tr> <Td> 9 </Td> <Td> Pennar </Td> <Td> Southeast </Td> <Td> Bay of Bengal </Td> <Td> 1.7 </Td> <Td> 6.32 </Td> <Td> 58 </Td> </Tr> <Tr> <Td> 10 </Td> <Td> Kaveri </Td> <Td> South </Td> <Td> Bay of Bengal </Td> <Td> 2.5 </Td> <Td> 21.36 </Td> <Td> 6.9 </Td> </Tr> <Tr> <Td> 10 </Td> <Td> East flowing rivers between Mahanadi and Pennar </Td> <Td> Central - east </Td> <Td> Bay of Bengal </Td> <Td> 2.7 </Td> <Td> 22.52 </Td> <Td> 19 </Td> </Tr> <Tr> <Td> 11 </Td> <Td> East flowing rivers between Kanyakumari and Pennar </Td> <Td> Southeast </Td> <Td> Bay of Bengal </Td> <Td> 3.1 </Td> <Td> 16.46 </Td> <Td> 13.1 </Td> </Tr> <Tr> <Td> 12 </Td> <Td> West flowing rivers between Tadri and Kanyakumari </Td> <Td> Southwest </Td> <Td> Arabian Sea </Td> <Td> 1.7 </Td> <Td> 113.53 </Td> <Td> 16.7 </Td> </Tr> <Tr> <Td> 13 </Td> <Td> West flowing rivers between Tapi and Tadri </Td> <Td> Southwest </Td> <Td> Arabian Sea </Td> <Td> 1.7 </Td> <Td> 87.41 </Td> <Td> 24.3 </Td> </Tr> <Tr> <Td> 14 </Td> <Td> Tapi </Td> <Td> Central - west </Td> <Td> Arabian Sea </Td> <Td> </Td> <Td> 14.88 </Td> <Td> 11.9 </Td> </Tr> <Tr> <Td> 15 </Td> <Td> Narmada </Td> <Td> Central - west </Td> <Td> Arabian Sea </Td> <Td> 3.1 </Td> <Td> 45.64 </Td> <Td> 14.5 </Td> </Tr> <Tr> <Td> 16 </Td> <Td> Mahi </Td> <Td> Northwest </Td> <Td> Arabian Sea </Td> <Td> 1.1 </Td> <Td> 11.02 </Td> <Td> 34.5 </Td> </Tr> <Tr> <Td> 17 </Td> <Td> Sabarmati </Td> <Td> Northwest </Td> <Td> Arabian Sea </Td> <Td> 0.7 </Td> <Td> 3.81 </Td> <Td> 3.1 </Td> </Tr> <Tr> <Td> 18 </Td> <Td> West flowing rivers between Kutch and Saurashtra </Td> <Td> Northwest </Td> <Td> Arabian Sea </Td> <Td> 10 </Td> <Td> 15.1 </Td> <Td> 1.9 </Td> </Tr> <Tr> <Td> 19 </Td> <Td> Rajasthan inland basin </Td> <Td> Northwest </Td> <Td> India </Td> <Td> 0 </Td> <Td> Negligible </Td> <Td> 15 </Td> </Tr> <Tr> <Td> 20 </Td> <Td> Indus tributaries </Td> <Td> Northwest </Td> <Td> Pakistan </Td> <Td> 10 </Td> <Td> 73.31 </Td> <Td> 46 </Td> </Tr> <Tr> <Td> </Td> <Td> Total (per International Treaty) </Td> <Td> </Td> <Td> </Td> <Td> 100 </Td> <Td> 1869.37 </Td> <Td> </Td> </Tr> </Table> <Tr> <Th> (hide) Basin number </Th> <Th> River basin unit </Th> <Th> Region </Th> <Th> Draining into </Th> <Th> Catchment area (% of river irrigated India) </Th> <Th> Average runoff (km) </Th> <Th> Additional available surface water (km) </Th> </Tr> <Tr> <Td> 1.1 </Td> <Td> Ganges (GBM) </Td> <Td> North </Td> <Td> Bangladesh </Td> <Td> 26.5 </Td> <Td> 525.02 </Td> <Td> 250 </Td> </Tr>

Which is the longest river in indian subcontinent