Pennar, also called Penna, drains southern AP toward the Nellore coast. Its major reservoir associations include Somasila, Kandaleru and Gandikota in the wider basin or transfer network. The Nellore Somasila project office names Cheyyeru, Papaghni, Chitravathi, Kundu and Sagileru among Pennar tributaries. A canal may add water from another basin, so not every unit in a scheme is a natural Pennar tributary.

The Penna basin is relatively dry compared with the great deltas; storage and transfer infrastructure are therefore important in its agricultural geography. Distinguish river basin from project supply source.

Worked example: The Penna, also called Pennar, is the southern basin anchor for Somasila and the Gandikota region. A map question may use one spelling in the stem and the other in the answer. They refer to the same river, but an irrigation transfer from another basin can still feed a linked project. Distinguish river of location from source of transferred water, especially in Telugu Ganga questions.

Active recall: Locate the named river or project on the relevant map, name its function, and state which facts need a dated source.