The Kosi is a perennial river like the Ramganga and its catchment lies partially in Corbett NP. From Mohan through Dhikuli till Ramnagar, the Kosi forms the eastern boundary of Jim Corbett National Park. Even though the Kosi does not enter the Park boundary, wild animals from Corbett use it for drinking especially during pinch periods. Its bed is strewn with boulders and its flow is erratic and often changes course. Kosi is notorious for its unpredictable and damaging torrents during monsoon.