I'm putting in a drainage system on my property including 12" drain basins in low spots on one side of the house and under downspouts. Probably going to use a light weight solid drainage pipe like, http://m.homedepot.com/p/4-in-x-10-ft-Triplewall-Pipe-Solid-4550010/100135310
I often see people laying a gravel need under the pipe and over. Is that only useful for perforated pipe or is there a reason to do it on solid pipe as well? Buried PVC for instance doesn't require a gravel bed? Should the drain boxes be on a gravel bed too?