Before revision: French drains to get the gutter water out from the retaining wall areaA diagram of a traditional French drain A French drain (also called a weeping tile, 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 both, with or without a perforated pipe that redirects surface water and groundwater away from an area.
After revision: A diagram of a traditional French drainArea of gravel at foot of retaining wall to encourage water away from the wall (French drain): note the gutter discharges away from the retaining wall A French drain (also called a weeping tile, 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 both, with or without a perforated pipe that redirects surface water and groundwater away from an area.