French Drain
Water
A covered ditch containing a layer of fitted or loose stone or other pervious material.
An underground passageway for water through the interstices among stones placed loosely in a trench.
- — Service Hydrologist Reference Manual Glossary of Hydrologic Terms retrieved 2014-06-01
Weather
In hydrologic terms, an underground passageway for water through the interstices among stones placed loosely in a trench