Discontinuity of Channel Substrate

Crossing structures that lack any natural substrate or contain substrates (including riprap, baffles, or other armoring) that contrast with the natural stream channel create discontinuities in streambed habitats. Many benthic (streambed-dwelling) organisms are confined to the streambed and can only move through appropriate substrates. Streambed discontinuities caused by crossing structures disrupt and fragment populations of these benthic organisms.