Jerome

And the water subsided, and the fountains of the deep were revealed, and the floodgates of heaven were opened. The interpreters have translated the phrase 'fountains of the deep were revealed' as 'the closed and sealed fountains were opened'. And regarding the following phrase: 'the water subsided from the earth', it is written that 'the waters returned from the earth, going and coming' (Ecclesiastes 1:7). Note, according to Ecclesiastes, that all waters and torrents return to the hidden veins of the abyss.

Hebrew Questions on Genesis ↗

Bede

And the fountains of the deep were closed, and the windows of heaven, and the rains from heaven were restrained, and the waters returned from the earth, going and coming, and they began to decrease after one hundred and fifty days. What is said, that the waters returned from the earth going and coming, clearly indicates according to the letter that all the courses of rivers and streams return through the hidden veins of the earth to the matrix of the abyss, according to Solomon: All the rivers run into the sea, yet the sea does not …

Commentary on Genesis (Hexaemeron) ↗