Nagavali flows through the north-eastern hill-to-coast region and is associated with Parvathipuram Manyam and downstream coastal districts. Thotapalli is a named barrage on the Nagavali. A natural river may cross several present district boundaries, so do not define a basin by a single district name. Its older reports can print former Vizianagaram before the 2022 district split.

Study the two northern rivers side by side: Vamsadhara-Gotta and Nagavali-Thotapalli. The names are close on a map but answer different river-project options.

Worked example: A north-eastern question names the Nagavali river and asks for a project. Thotapalli is the expected barrage association. Work from the river line and project point rather than a memorised district, since administrative boundaries have changed. A river may cross state or district borders; the headwork has a site. Describe that distinction if the options mix a river basin, a reservoir and a district name.

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