Matsya Purana — Cosmography of Jambūdvīpa: Varṣas
उत्तरेण तु श्वेतस्य पार्श्वे शृङ्गस्य दक्षिणे वर्षं हिरण्वतं नाम यत्र हैरण्वती नदी //
uttareṇa tu śvetasya pārśve śṛṅgasya dakṣiṇe varṣaṃ hiraṇvataṃ nāma yatra hairaṇvatī nadī //
To the north of Mount Śveta, on the southern flank of the Śṛṅga peak, lies the region called Hiraṇvata, where the river Hairaṇvatī flows.
This verse is not about pralaya; it belongs to cosmography, mapping a named region (Hiraṇvata) and its river (Hairaṇvatī) relative to mountains/peaks.
Indirectly, such geographic catalogues frame the Purana’s sacred world-view—useful for kings and householders in understanding pilgrimage landscapes and the cultural idea of ordered territories, but no direct dharma rule is stated here.
No explicit Vastu or ritual procedure appears; the significance is topographical—locating a varṣa and river, which can contextualize later tīrtha (sacred site) or pilgrimage references.