Matsya Purana — Yuga Durations
आश्रमाणां विपर्यासः कलौ सम्परिवर्तते वर्णानां चैव संदेहो युगान्ते रविनन्दन //
āśramāṇāṃ viparyāsaḥ kalau samparivartate varṇānāṃ caiva saṃdeho yugānte ravinandana //
In the age of Kali, the order of the āśramas becomes inverted and thoroughly disturbed; and at the end of the age, O son of the Sun, even the distinctions of the varṇas fall into doubt and confusion.
It does not describe the flood or cosmic dissolution directly; it gives a yugānta (end-of-age) symptom: dharma collapses socially, shown by the breakdown of āśrama discipline and the blurring of varṇa distinctions—typical preludes to major cyclical transitions.
It warns that in Kali-yuga the king must actively protect dharma—supporting proper education, rites, and ethical conduct—because the āśrama system (especially brahmacarya and gṛhastha responsibilities) becomes disordered, leading to social instability and loss of righteous livelihood.
No specific Vastu or temple rule is stated; the ritual takeaway is that traditional āśrama-based discipline and varṇa-based ritual roles become confused in Kali-yuga, implying that rites and social-religious duties require careful, dharma-aligned supervision to remain valid and meaningful.