noun
underground water; subterranean stream
Refers to water flowing beneath the surface, often in the context of geology, civil engineering, or environmental studies. Not a general term for groundwater; specifically implies a flowing body of water underground.
この地域では伏流水が豊富で、井戸を掘るとすぐに水が出る。
In this area, underground water is abundant, and water comes out quickly when you dig a well.
トンネル工事中に伏流水が湧き出して、作業が一時中断された。
During tunnel construction, an underground stream gushed out, temporarily halting the work.