Matsya Purana — Navagraha Sacrifice for Planetary Pacification and Prosperity
चतुरङ्गुलविस्तारा मेखला तद्वदुच्छ्रिता प्रागुदक्प्लवना कार्या सर्वतः समवस्थिता //
caturaṅgulavistārā mekhalā tadvaducchritā prāgudakplavanā kāryā sarvataḥ samavasthitā //
The surrounding band (mekhalā) should be made four aṅgulas in width, and raised to the same measure. A drainage fall should be constructed toward the east and toward the water-side (udak, i.e., north), and it should be evenly set on all sides.
This verse is not about Pralaya; it belongs to the Vāstuvidyā stream, prescribing practical construction measures—especially the base-band (mekhalā) and the intended directional slope for water runoff.
It supports the duty of maintaining orderly, safe, and auspicious built spaces—kings for public works and temples, householders for dwellings—by mandating standard measurements, correct orientation, and proper drainage to prevent decay and disorder.
Architecturally, it specifies a four-aṅgula-wide, equally raised mekhalā (a base moulding/plinth-band) and an intentional slope for drainage oriented eastward and toward the water-side, with uniform alignment on all sides—key Vāstu principles for longevity and auspiciousness.