Matsya Purana — Division of Bhārata-varṣa
तासां नद्युपनद्यश्च शतशो ऽथ सहस्रशः तास्विमे कुरुपाञ्चालाः शाल्वाश्चैव सजाङ्गलाः //
tāsāṃ nadyupanadyaśca śataśo 'tha sahasraśaḥ tāsvime kurupāñcālāḥ śālvāścaiva sajāṅgalāḥ //
Of those great rivers there are hundreds, even thousands, of rivers and tributaries; along them dwell these peoples—the Kurus and the Pañcālas, the Śālvas, and also the Jāṅgalas (folk of the forest or dry regions).
This verse does not discuss Pralaya; it is part of the Matsya Purana’s geographic survey, emphasizing the immense network of rivers and tributaries and the peoples settled along them.
Indirectly, it supports rajadharma by mapping janapadas and river systems—key for governance, taxation, agriculture, pilgrimage routes, and protection of settlements dependent on riverine resources.
No direct Vastu or ritual rule is stated; however, the focus on rivers and tributaries aligns with site-selection priorities in temple/town planning where proximity to watercourses is treated as auspicious and practical.