Matsya Purana — Paurava Genealogy
त्यक्त्वा विवक्षुर्नगरं कौशाम्ब्यां तु निवत्स्यति भविष्याष्टौ सुतास्तस्य महाबलपराक्रमाः //
tyaktvā vivakṣurnagaraṃ kauśāmbyāṃ tu nivatsyati bhaviṣyāṣṭau sutāstasya mahābalaparākramāḥ //
Abandoning the city, Vivakṣu will dwell at Kauśāmbī. He will have eight sons, endowed with great strength and heroic prowess.
This verse does not discuss Pralaya; it belongs to a genealogical narrative, recording a king’s relocation to Kauśāmbī and the continuation of lineage through eight sons.
Indirectly, it reflects the Purāṇic ideal of dynastic continuity: a ruler establishes residence/seat of power and ensures succession through capable heirs, described here as strong and valorous.
No explicit Vāstu or ritual rule is stated; the only practical takeaway is the political act of shifting residence to a named city (Kauśāmbī), relevant to historical geography rather than temple architecture.