Matsya Purana — Cosmography of Śākadvīpa and Successive Dvīpas: Mountains
धूतपापा नदी नाम योनिश्चैव पुनः स्मृता सीता द्वितीया विज्ञेया सा चैव हि निशा स्मृता //
dhūtapāpā nadī nāma yoniścaiva punaḥ smṛtā sītā dvitīyā vijñeyā sā caiva hi niśā smṛtā //
A river is known as Dhūtapāpā (“the washer-away of sins”); it is also remembered again by the name Yonī. The second is to be understood as Sītā, and that same one is also remembered as Niśā.
This verse is not about Pralaya; it is a tirtha-style catalog noting alternate traditional names of rivers, emphasizing their purifying (sin-removing) status.
By preserving and teaching recognized tirtha and river-name traditions, a king supports dharma and pilgrimage culture; householders gain a practical cue for merit (puṇya) through reverence and bathing/ritual association with such rivers.
The ritual takeaway is the identification of rivers as purifiers and the correct recognition of their alternate names—useful for sankalpa (ritual intent statements) and pilgrimage rites, though no Vastu or temple-building rule is specified here.