Matsya Purana — Ekoddiṣṭa Śrāddha
यावदब्दं नरश्रेष्ठ सतिलोदकपूर्वकम् ततः संवत्सरे पूर्णे सपिण्डीकरणं भवेत् //
yāvadabdaṃ naraśreṣṭha satilodakapūrvakam tataḥ saṃvatsare pūrṇe sapiṇḍīkaraṇaṃ bhavet //
O best of men, for the space of a year one should perform the rites beginning with offerings of water mixed with sesame; then, when the year is fully completed, the sapiṇḍīkaraṇa—joining the departed to the ancestral line—should be performed.
This verse does not address pralaya; it focuses on ritual timekeeping in śrāddha—maintaining offerings for a year and then performing sapiṇḍīkaraṇa.
It lays down gṛhastha-dharma: the householder (and by extension a ruler as guardian of dharma) should ensure proper ancestor rites—regular tilodaka offerings for a year after death, followed by the formal sapiṇḍīkaraṇa.
The significance is ritual rather than architectural: it specifies the sequence and timing—tilodaka-based observances for one year, then the sapiṇḍīkaraṇa rite that ritually affiliates the deceased with the ancestral piṇḍa group.