- Drainage Net, also called Composite Geonet, is a two or three-layer three-dimensional drainage geosynthetic product which are often made with polypropylene PP or regenerated HDPE (geonet) and covered with double-sided thermally heat-bonded nonwoven geotextile on both sides or one side. BPM brand drainage net has excellent performance than traditional draining gravel. So it becomes a good alternative for gravel in drainage application. Our drainage net is widely used for landfill, railway system drainage, road drainage, tunnel and retaining wall.