water system; river system; drainage system
Refers to the network of rivers, streams, and drainage in a region. Often used in geography, environmental science, and civil engineering contexts.
この地域の水系は、大雨のたびに氾濫しやすい。
The water system in this area tends to flood whenever there is heavy rain.
利根川水系には多くの支流が含まれている。
The Tone River system includes many tributaries.
The Tone River system spans a wide area of the Kanto region.
This river belongs to the Tone River system.
Wastewater from the factory polluted the surrounding water system.
Activities are being carried out to conserve the local water system.