Example rock cluster or rock band layout used to stabilize the low flow channel.

A plan view of a culvert with a stream channel running through it. Rock clusters and rock bands are depicted spaced at five times the bankfull width maximum or a maximum of 0.8 feet elevation difference between these structures. Rock clusters span the partial culvert width and rock band span the full culvert width. The rock bands and rock clusters are designed from material that's designed for stability at the 100-year flood flow. The channel substrate material is designed for stability at the 50-year flood flow. At least one half bankfull width is provided between the culvert inlet or outlet and a rock band or rock cluster structure.