French drain
A French drain or weeping tile ( also trench drain , filter drain , blind drain , rubble drain , rock drain , drain tile , perimeter drain , land drain , French ditch , sub-surface drain , sub-soil drain or agricultural drain ) is a trench filled with gravel or rock or containing a perforated pipe that redirects surface water and groundwater away from an area . 
<triplet> surface water <subj> groundwater <obj> opposite of <triplet> groundwater <subj> surface water <obj> opposite of