Altered river and stream reaches are those that are specifically identified as canals or ditches. These represent areas where the hydrography, flow, and water quality may be highly altered compared to natural conditions.
Networks are characterized by the percent of their total network length that is in altered river and stream reaches.
Rivers and streams altered by artificial channelization to create canals and ditches may have a lower variety and quality of in-stream habitat due to differences in hydrography, flow, water quality, and other factors compared to natural stream channels. Barriers with more highly altered upstream networks may contribute less natural habitat if removed.
Rivers and streams with lower amounts of artificial channelization to create canals and ditches may have a wider variety of higher-quality in-stream habitat. Barriers with less altered upstream networks may contribute more natural habitat if removed.