TgO Ex7:24 :וַחפַרוּ כֹל מִצרָאֵי סַחרָנוּת נַהרָא מַיָא לְמִשתֵי‏ : all the Egyptians dug for water to drink in the surroundings of the river
See the entire entry for sḥrnw n.f. surroundings