אֶפְתַּ֤ח עַל־שְׁפָיִים֙ נְהָר֔וֹת וּבְת֥וֹךְ בְּקָע֖וֹת מַעְיָנ֑וֹת אָשִׂ֤ים מִדְבָּר֙ לַאֲגַם־מַ֔יִם וְאֶ֥רֶץ צִיָּ֖ה לְמוֹצָ֥אֵי מָֽיִם׃
I will open rivers on the high hills, And fountains in the midst of the valleys; I will make the wilderness a pool of water, And the dry land springs of water.
Ibn Ezra on Isaiah
שפים High places. It is the opposite of בקעות valleys. This also is wonderful, that rivers will be found on high places.