The Krishna and Godavari rivers are the largest and broadest in South India. In Andhra Pradesh all the rivers generally flows from northwest to southeast. Except Godavari, Pennar, Krishna, Tungabhadra, Bhima, Manjeera, Pranahita, all rivers have their source at East mountainsides and destination at Bay of Bengal. The Deccan rivers (Godavari and Krishna) contribute about 30 % of the total out flow in India. Of this, the rivers that flow from the west to east account for 20 % and those from the east to west about 10 %.