Matsya Purana — Lineage of Yayāti through Yadu and the Deeds of Kārtavīrya Arjuna
एको बाहुसहस्रेण वगाहे स महार्णवम् करोत्युद्वृत्तवेगां तु नर्मदां प्रावृडुद्धताम् //
eko bāhusahasreṇa vagāhe sa mahārṇavam karotyudvṛttavegāṃ tu narmadāṃ prāvṛḍuddhatām //
With a single arm he can plunge into the great ocean; yet he makes the Narmadā—swollen and raging in the monsoon—surge with an even more tumultuous force.
It does not describe Pralaya directly; it uses oceanic imagery to magnify the Narmadā’s power, portraying her monsoon current as surpassing even the vastness associated with the ocean.
Indirectly, it supports the Purāṇic ethic of honoring tīrthas and sacred rivers—encouraging householders (and rulers who sponsor pilgrimages) to revere and approach such powerful waters with devotion and restraint.
No Vāstu rule is stated; the ritual takeaway is the exaltation of the Narmadā as a potent tīrtha—implying heightened sanctity for river-side rites (snāna, tarpaṇa, and pilgrimage observances), especially during the monsoon when her force is emphasized.