The River Aghanashini originates from Gadihalli (Sirsi) at an altitude of 676m above M.S.L in the Western Ghats of Karnataka State. The river has a catchment area of 1350 sq km and its length up to the confluence to the Arabian Sea is 117 km. The river flows mostly through forest areas and has intermittent structures of rocky bed (with rock out crops), deep stagnant pools and channelled flow with island formation. No major or medium projects exist on the river. The CWC Hydrological Observation Station is located at Santeguli on this river.