Matsya Purana — Yayāti and His Sons: The Exchange of Youth and Old Age
नौर् उपप्लवसंचारो यत्र नित्यं भविष्यति अराज्यभोजशब्दं त्वं तत्र प्राप्स्यसि सान्वयः //
naur upaplavasaṃcāro yatra nityaṃ bhaviṣyati arājyabhojaśabdaṃ tvaṃ tatra prāpsyasi sānvayaḥ //
Where the movement of boats amid the overwhelming flood becomes a constant occurrence, there you will encounter the cry, “O king, give us food!”—together with your people and dependents.
It depicts pralaya as a sustained, society-altering flood where boat-travel becomes routine, indicating prolonged inundation and widespread displacement.
The cry “O king, food!” implies the ruler’s dharma in crisis: providing sustenance and protection to subjects and dependents, especially during famine-like conditions caused by flooding.
No specific Vastu or temple-building rule appears here; the practical takeaway is logistical preparedness (boats and provisioning) as part of dharmic governance during pralaya conditions.