As it nears the sea, the speed of water in the river decreases and is no longer able to carry the silt and sand. It deposits them on its own course, which then gets filled up. When flood waters come again, they have to cut through new channels to reach the sea. Thus, towards the end of its journey to the sea, the river forms a delta. River Krishna and Godavari form deltas in the Eastern Coast. They have water through out the year. However, we also have a number of small rivers that have water only during the rainy season.

Why is this so?

Rivers like Krishna and Godavari starts from the Western Ghats, which receive heavy rainfall. The rain water slowly percolates into the ground and flows into the river all through the year. On the other hand, many rivers which start from the dry regions like Dindi, Manjeera, Musi are fed by scanty rainfall. Others, which start in the Eastern Ghats, receive only moderate rainfall and the water flows rapidly into the sea. That is why they go dry during the non-rainy season.