(Last Updated on : 25-05-2015)
The climate of the drainage basin in Krishna River is dominated by the southwest monsoon, which provides most of the precipitation for the entire region. High water level is found in the river during the month of August - November and low water is from April to May, especially at Vijayawada. Climatic feature ranges from per-humid through dry sub-humid in the west through semi-arid in the central and eastern parts of the basin. However, only in the very south central part of the basin is acutely dry.
The geology of the drainage basin is subjugated in the northwest by the Deccan Traps, in the central part is uncategorized crystalline and in the east by the Cuddapah Group. The Dharwars lies in the southwest central and the Vindhian lies in the east central. This formation is a significant part of the outcrops within the unclassified crystalline. The deltaic region itself is formed mainly of Pleistocene to Recent material.
The Krishna River is also known in mythology. The drainage basin originates near Mahabaleshwar [1438 m.] in Maharashtra State within the Western Ghats. In the terms of geology this is the Dharwar [Karnataka] Craton, which is a Granite-Gneiss-Greenbelt massif. The provenance consists of Deccan Traps and the Dharwar Archean rocks. From its source the river flows east-northeast to the town of Wai for about 1280 kilometers and then east-southeast for the last 80 kilometers, passed Sangli into Karnataka State and then Andhra Pradesh. It final empties into the Bay of Bengal. The total drainage length of Krishna River is 25,344 km with a total annual mean runoff of 55764 million cusecs and a maximum - minimum discharge of 33810 - 3 cusecs. The total length of the river is 968 km and it's drainage basin shares a common border with that of the Godavari River, lying to the north. The river drains 305,300 sq km and the drainage density is quite high being 0.22 km stream length per 500 sq km.
About 75% of the basin is under a semi-arid climate, receiving monsoon rainfall. The rainfall of the Krishna delta is 910 mm with precipitation mainly in June all through October. The temperature of the drainage basin is around 22 - 27.5 - 34 C.