Didn't He Sayوَهُوَ الَّذِي مَرَجَ الْبَحْرَيْنِ هَٰذَا عَذْبٌ فُرَاتٌ وَهَٰذَا مِلْحٌ أُجَاجٌ وَجَعَلَ بَيْنَهُمَا بَرْزَخًا وَحِجْرًا مَّحْجُورًا
"And it is He who has released the two seas, one fresh and sweet and one salty and bitter, and He placed between them a barrier and prohibiting partition."
Qur'an 25:53 · trans. Saheeh International
Salt-wedge stratification and haloclines keep fresh and saline water masses measurably distinct where rivers meet the sea. But the surface of the phenomenon is visible to any estuary sailor, and classical exegesis already read the verse as rivers entering the sea uncorrupted. Because the text matches the measurement without requiring knowledge beyond observation, the record is stamped ALIGNED — the honest stamp for a fit that cannot be claimed as foreknowledge.
[10] Open University, Ocean Circulation (2nd ed.) · al-Ṭabarī, Jāmiʿ al-bayān ad 25:53