Matsya Purana — Rite and Layout for Consecrating Ponds
प्रागुदक्प्रवणे देशे तडागस्य समीपतः चतुर्हस्तां शुभां वेदीं चतुरस्रां चतुर्मुखाम् //
prāgudakpravaṇe deśe taḍāgasya samīpataḥ caturhastāṃ śubhāṃ vedīṃ caturasrāṃ caturmukhām //
In a place that slopes toward the east and the north, and close to a pond, one should prepare an auspicious altar (vedī) measuring four hastas, square in shape, and furnished with four fronts (oriented to the four directions).
This verse does not address Pralaya; it is a Vastuvidya instruction focused on choosing auspicious terrain and specifying the altar’s form and measurements.
It supports the duty of establishing orderly, auspicious ritual and civic spaces—guiding rulers/householders to select proper land (east/north slope) and to build correctly measured, directionally aligned platforms for ceremonies or construction rites.
It prescribes a square, four-direction-facing vedī of four hastas, placed near a water source and on an east/north sloping site—key Vastu markers for auspicious orientation, stability, and ritual suitability.