Matsya Purana — Characteristics of Dvāpara and Kali Yugas
द्वापरादौ प्रजानां तु सिद्धिस्त्रेतायुगे तु या परिवृत्ते युगे तस्मिंस् ततः सा वै प्रणश्यति //
dvāparādau prajānāṃ tu siddhistretāyuge tu yā parivṛtte yuge tasmiṃs tataḥ sā vai praṇaśyati //
At the beginning of the Dvāpara Yuga, the siddhi (spiritual attainment) of people that existed in the Tretā Yuga—when that age turns over and changes—then indeed perishes.
It does not describe Pralaya directly; it explains cyclical time through Yuga transition, stating that a prior-age spiritual attainment (siddhi) declines when the next Yuga begins.
It implies that dharma-practice must be adapted to the Yuga: rulers and householders should not assume earlier-age capacities, but uphold achievable discipline, justice, and ritual according to the diminished conditions of the later age.
No direct Vāstu or temple-rule is stated; the ritual takeaway is the Yuga-based principle that the efficacy and intensity of practices (and results like siddhi) are time-conditioned in Purāṇic cosmology.