Matsya Purana — Cosmography of Śākadvīpa and Successive Dvīpas: Mountains
ताः पिबन्ति सदा हृष्टा नदीर्जनपदास्तु ते एते शान्तभयाः प्रोक्ताः प्रमोदा ये च वै शिवाः //
tāḥ pibanti sadā hṛṣṭā nadīrjanapadāstu te ete śāntabhayāḥ proktāḥ pramodā ye ca vai śivāḥ //
Those regions and their people joyfully drink from the rivers at all times. These districts are declared to be free from fear—places of delight, and indeed auspicious (śiva) in nature.
It does not describe cosmic pralaya directly; instead, it highlights an ideal, protected earthly order where settlements thrive by rivers and are described as “fearless” and auspicious—an image of stability rather than dissolution.
By praising river-fed, fear-free janapadas, the verse implicitly supports royal duty (rājadharma) to secure water access, protect inhabitants from danger, and maintain prosperity; for householders, it affirms the value of living in well-watered, safe, and ritually auspicious regions.
While not giving technical measurements, it elevates proximity to rivers and the quality of “fearlessness/auspiciousness” as criteria for choosing a settlement site—ideas aligned with Vastu thinking about water sources, wellbeing, and the auspicious character of land.