Corrugated metal pipe (CMP) is the “go-to” material for most stormwater detention and infiltration projects. A wide range of gages, corrugations, and diameters provides engineers flexibility in design not available with other materials. In addition, the industry has developed several pipe coatings and materials to accommodate site-specific

Stormwater detention systems often include a large portion of the storage volume within the voids of the backfill material. Depending on the underground structure design and size, allocated storage within the stone voids can vary between 25-60% of the overall storage for the project. The generally accepted number has been 40% stone void space.