The melting of icebergs and ice shelves.
When salt water freezes. the salt is squeezed out of the crystals. The resulting crystals are mainly pure solid crystal water ( with some impurities of course) The icebergs are formed when fresh water frozen in glaciers break off into the ocean.
Melting the solid water results in fresh water. One plan for supplying fresh water to costal cities was to tow ice bergs to the city where it could be converted into fresh water.