A basin follows watersheds; a district follows government boundaries. The Krishna basin crosses several AP districts and other states, while a district may contain parts of multiple small catchments. Engineering projects can transfer water across basins. The APSDMA district map is therefore a locator layer over a separate river layer.

When a district splits, the basin remains in place. A 2023 project report that says Kurnool or Prakasam may use an older boundary. Answer the river from hydrology and the district from the question date.

Worked example: The Godavari basin is a hydrological area, while East Godavari, Konaseema and Polavaram are administrative districts. Their boundaries do not trace the watershed. A district can contain sites in different sub-basins and a basin can cover many districts or states. In a map question, identify whether the shaded shape is a catchment or a district polygon before answering. The legend and source agency usually reveal the distinction.

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