A French drain is a trench filled with gravel or rock that contains a perforated pipe. The trench is designed to redirect surface water and groundwater away from specific areas. The drain works by allowing water to flow into the trench, through the gravel, and into the perforated pipe, which then carries the water away to a designated drainage area, such as a storm drain, dry well, or... https://texasgardenmaterials.com/landscape-design-houston-tx/french-drain-installation-houston-tx/