Rabbi Yehoshua ben Levi said: the whole world drinks from the runoff of the Garden of Eden, as it is said, "And a river goes out from Eden" (Genesis 2:10) and so on. It was taught: from the runoff (of the Garden of Eden, which is sixty times more than the whole world, for one kor is thirty se'ah, and a se'ah is four kav), a field of a kor's size drinks a half-se'ah measure.
The Whole World Drinks From the Runoff of Eden
Yalkut Shimoni on Torah 22:3
אָמַר רַבִּי יְהוֹשֻׁעַ בֶּן לֵוִי, כָּל הָעוֹלָם כֻּלּוֹ מִתַּמְצִית גַּן עֵדֶן הוּא שׁוֹתֶה שֶׁנֶּאֱמַר וְנָהָר יוֹצֵא מֵעֵדֶן וְגוֹ'. תָּנָא, מִתַּמְצִית (דְּגַן עֵדֶן ס' פְּעָמִים נֶגֶד כָּל הָעוֹלָם דְּהָא א' כּוּר ל' סְאָה וּסְאָה ד' קַבִּין) בֵּית כּוּר שׁוֹתָה תַּרְקַב.