Boann's tears
According to the legends, Ulim lake was generated by the tears of Boann, goddess of rivers, lakes and springs, due to the eternal segretation from is beloved Lyr, god of seas.
Summary
Boann, Nuada's offspring, fell in love with Lyr, helmsman of the tribe, but he was married with their mother Rhiannon, who once was engaged to their father. In the attempt to limit the contacts between his child and Lyr, for whom he felt jealousy and mistrust, Nuada gifted Boann with the power over fresh water. Once the young divinity discovered to have been tricked by the father, cried for days and the tears collecting on the soil formed a salt lake that was their gifted to their beloved Lyr. Unfortunaly for Boann, their love would never be genuinely reciprocated by the lord of the seas, although every river that flows into the sea will allow them to embrace their beloved just for a moment.
Historical Basis
The historical characters and relationships behind the myth are the complex relations involving Rhidgaer II, Rhidgaer III, Lyrathir and Zhanti. The unusual feature of Ulim lake couldn't escape from having a mystical explanation tributed by the superstitious Hintadu.
In Literature
A story of love and jealousy such as the one on the background of this myth was deemed to attract the attention of poets and bards, who have written numerous poems and ballads inspired by this myth.
In Art
The sad androginous character of Boann has been portrayed but a large number of painters through the centuries, often with approaches diametrically opposed. Particularly famous is the painting realized by Jacopo mi Lichtian.(on the side panel).
Interesting myth to explain the difference between salt and fresh water. I like it. :)
Thank you!