D4RUNOFF NBS Library: https://d4runoff.eu/resources/

Infiltration trenches can be defined as simply linear soakaways and are shallow excavations covered with rubble or stone that enhance the natural ability of soil to drain water. An Infiltration Trench is a linear stormwater BMP consisting of a continuously perforated pipe at a minimum slope in a stone-filled trench.  An Infiltration Trench may be used as part of a larger storm sewer system, such as a relatively flat section of storm sewer, or it may serve as a portion of a stormwater system for a small area, such as a portion of a roof or a single catch basin. In all cases, an Infiltration Trench should be designed with a positive overflow. Usually, an Infiltration Trench is part of a conveyance system. Their main function is to infiltrate runoff water and hence are normally used as end of train systems or to infiltrate runoff water from nearby impervious areas.