Somasila Project is built across the Penna near Somasila in current Sri Potti Sriramulu Nellore district. The official project-circle page gives its design objectives, including stabilising irrigation and transmitting water toward Kandaleru. It is a storage reservoir; the volume in it on any date is not its fixed design capacity.

The river-project pair is Penna-Somasila. Do not confuse Somasila in Nellore with the Srisailam reservoir on Krishna; similar initial letters conceal different basins.

Worked example: Somasila is on the Penna in the Nellore water system. When a question offers Kandaleru as an alternative, do not collapse them into one reservoir: Somasila is a distinct upstream storage point, while Kandaleru is another storage component in the linked southern network. Trace the Penna line and the reservoir-to-reservoir connection separately. A live storage number needs a date and unit from the district or state portal.

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