The Vamsadhara is a north-eastern east-flowing river associated with Srikakulam and the Odisha-facing drainage. Its water geography links hills, headworks, canal delivery and flood movement toward the coast. Gotta is the high-yield barrage anchor on this river. Cross-border catchment facts and inter-state issues require a dated source; the stable exam pair is river and headwork.
A barrage diverts regulated flow; the distribution canals serve command areas that may differ from the river floodplain. Do not infer annual irrigation achievement simply from a designed command area.
Worked example: An MCQ pairs Vamsadhara with Gotta. Explain the pairing by following the north-eastern river corridor to the barrage before thinking of a district. The Vamsadhara is not the Nagavali, and the existence of two nearby irrigation structures does not make their source rivers interchangeable. If an older district name appears in a source, separate that administrative date from the stable river-to-headwork relationship shown on the basin map.
Active recall: Locate the named river or project on the relevant map, name its function, and state which facts need a dated source.