Albert Barnes Commentary Psalms 107:33

"He turneth rivers into a wilderness, And watersprings into a thirsty ground;" — Psalms 107:33 (ASV)

He turneth rivers into a wilderness – He makes great changes in the earth; he shows that he has absolute dominion over it. (See the notes at Isaiah 44:26-27). Regarding the word “wilderness,” see the notes at Psalm 107:4. The point here is that God had such control over nature that he could make the bed of a river dry and barren like the rocky or sandy desert. He could effectively dry up the stream and make it so dry and parched that nothing would grow but the most stunted shrubs, like those found in the waste and sandy desert.

And the water-springs into dry ground – this means the very fountains of the rivers: not only drying up the river itself by leading it off into burning wastes where it would be evaporated by the heat or lost in the sand, but also so directly affecting the “sources” of the streams as to make them dry.