Exodus 15:27

And they came to Elim; and in Elim were twelve fountains of water, a fountain for each tribe; and seventy palm-trees, corresponding with the seventy elders of Israel: and they encamped there by the waters.

AND THERE WERE TWELVE SPRINGS OF WATER, AND THREE SCORE AND TEN PALM TREES. It is not such a significant matter that seventy palm trees are found in a certain place. In the lowlands, a thousand and more palm trees can be found in one location, and springs of abundant water are springing forth in valleys and hills, and Scripture does not mention them at all! [Why then are these springs and palm trees singled out here?]
Now Rabbi Abraham ibn Ezra explained that Scripture narrates that they came to a good place which was unlike Marah. In Elim, there were many springs, and the waters were sweet and good, since palm trees cannot thrive in soil where the waters are bitter. It is for this reason that Scripture says here and they encamped there, because on account of it, they stayed there for more days than in the other places they passed through. In the section of Eileh Mas’ei, however, Scripture does not relate anything about Marah, and yet it states, And they journeyed from Marah, and came unto Elim; and in Elim were twelve springs of water, and three score and ten palm trees, and they encamped there,, Verse 9. Accordingly Ibn Ezra’s explanation that the springs and palm trees of Elim were mentioned here in order to contrast with Marah, where the waters were bitter, cannot be correct, because there in Eileh Mas’ei, Scripture states nothing about Marah and yet mentions the same about Elim as here. and a description of a place at such length is not found there about any of the places they traversed!
Now Rashi wrote: “Twelve springs of water, a number corresponding to the twelve tribes of Israel, were ready for them. And seventy palm trees — these corresponded to the seventy elders.” But I do not know the nature of this preparation, i.e., whether it was done for them by a miracle just for that time. I have however, seen here in the Mechilta: “Rabbi Eleazar of Modaim said: ‘On the very day that the Holy One, blessed be He, created His world, He created twelve springs corresponding to the twelve tribes of Israel, and seventy palm trees corresponding to the seventy elders.’” Scripture thus tells that each tribe encamped beside his spring and the elders sat in their shade praising G-d for them, because He had prepared for them [such a restful place] in a land of drought. Our Rabbis have yet another explanation in the Midrash of Rabbi Nechunya ben Hakanah on this verse, which is wonderful in our eyes.

שתים עשרה עינות מים, in spite of this, the people moved on from there.