מדרש על ברכות 9:3

Rabbi Zadok said: On the 10th of Marcheshvan all the creatures entered the ark; on the 17th of the same (month) the waters of the Flood descended from heaven upon the earth, for they were the waters (endowed with the) male (principle). And there came up the waters of the depths, for they are the waters (endowed) with the female (principle), and they were joined with one another, and they prevailed so as to destroy || the world, as it is said, "And the waters prevailed exceedingly upon the earth" (Gen. 7:19).