In-Stream Habitat Alteration refers to lost in-stream habitat due to human modification of a waterway’s bed, banks, or flow. Modification of a stream’s bed or banks happens when streams are channelized, sent through culverts, dammed, dredged or filled. Out of stream infrastructure, such as curbs and gutters, storm-drains, and concrete ditches alter the rate of flow that enters a stream, quickly ushering water off impervious surfaces and sending it rushing into the stream channel. These modifications to streams result in an alteration of in-stream habitat.
Habitat alteration can disrupt native species reproductive cycles or simply make living conditions untenable for some aquatics, reducing taxonomic richness and diversity. It can also lead to the replacement of native species by exotic or invasive species or provide advantages to generalist species over specialist species.