Those white tubes in the picture are 4" corrugated drainage pipe wrapped in a cloth sock with foam rock-shaped filler between the sock and pipe. They cost about $40/10 ft, compared to maybe $10 for equivalent pipe/sock/drainage stone. The $40 ones are worth every penny. I laid 160 feet of them in twenty minutes two years ago. If I had done it the old-fashioned way, it probably would have been five hours and two chiropractor visits. Highly recommended option.
Thats all they use here now. The old way with the gravel must have been a huge hassle.