The Krishna rises near Mahabaleshwar in Maharashtra's Western Ghats. It flows through a major interstate basin before entering the Andhra region and reaches the Bay near Hamsaladeevi. The Tungabhadra is a major tributary of Krishna; it is not a second name for the main river. The Krishna's large upstream storages shape downstream supply, hydroelectric operation and interstate allocation. In AP exam preparation, draw the sequence Srisailam, Nagarjuna Sagar, Pulichintala, Prakasam Barrage, delta, sea.
Srisailam and Nagarjuna Sagar are large reservoirs on the Krishna system. Pulichintala is downstream of Nagarjuna Sagar and upstream of Prakasam Barrage. Prakasam Barrage at Vijayawada is a diversion and regulation structure that feeds the delta canal system. Calling every one of these simply a 'dam on Krishna' loses the functional differences that questions exploit. Storage manages seasonal water; a barrage mainly raises upstream level to divert flow; a canal transports water; a lift scheme raises it mechanically.
The Krishna delta is important for paddy, aquaculture, flood management and settlement. Flood behaviour depends on reservoir releases, local rain and tributary inflows such as Munneru and Budameru, not only rain where the delta lies. The river is also central to AP-Telangana water governance after bifurcation. The Act provides river-management boards and other arrangements; a geography answer should separate physical basin facts from legal allocation or current political claims.
In paired questions, check which river the structure actually crosses. Nagarjuna Sagar, Srisailam, Pulichintala and Prakasam Barrage belong to Krishna. Dowleswaram and Polavaram belong to Godavari. Somasila belongs to Penna. A correct map is faster and safer than memorising project names as an unstructured list.
Worked map reasoning
Put the four Krishna structures in upstream to downstream order: Srisailam, Nagarjuna Sagar, Pulichintala and Prakasam Barrage. Now ask what each does. The first three belong to the reservoir and regulation chain; the last is the familiar delta diversion point at Vijayawada. A multiple-choice pair can contain two real Krishna structures yet reverse their order. Reading the river from source to sea exposes that error.
Active recall: close the book, place the named river or region on a blank map, and explain one likely exam confusion in your own words.