The permafrost and seasonal ice formations at the poles are of fresh water. After winter ice melts colossal water currents, dwarfing the great rivers, flow across hemispheres right inside oceans. With appropriate technology they can satisfy the entire fresh water and electrical energy needs of the globe many times over. It is said that Arab countries are floating on an ocean of oil. But Bahrain has an ocean of sweet water also under its land and surrounding sea.
Fresh water rushes up bubbling from seabed.
The scene changes at Euphrates at high tides during new moon and full moon. The swelling sea water pushes the sea water back into the river and itself enters the river tract. In the process the river water surges laterally and irrigates the agricultural fields. Though this has taken place billions of times sea water never inundates the fields. It reaches back into the sea when high tide is over.