透とう水すい層そう

noun

permeable layer; pervious layer

Geological term for a subsurface layer that allows water to pass through, such as sand or gravel.

• この地ち域いきの透とう水すい層そうは地ち下か水すいの重じゅう要ような供きょう給きゅう源げんです。

  The permeable layer in this area is an important source of groundwater.