What is the verse that indicates the existence of a fresh water sea amidst the salty ocean waters, and its interpretation?

The verse indicating that Allah merged two seas without them mixing is His saying: ﴿And it is He who has released [simultaneously] the two seas, one fresh and sweet and one salty and bitter, and He has made between them a barrier and an impenetrable partition.﴾ [Al-Furqan:53]. The meaning of the verse is that Allah created fresh water (like rivers, springs, and wells) and salty water (like seas), and placed between them a barrier that prevents their mixing. Even if a fresh river flows into a salty sea, it cuts through it without mixing, and this is from the immense power of Allah.