Direct changes to stream banks and channels such as dikes, revetments, ditching, stream-adjacent roads, and gravel removal that impact the way streams provide habitat for fish are recorded by stream segment.
Within SSHIAP, degrading factors are generally limited to those visible on maps and aerial photos, or those for which records exist (e.g. WDFW Hydraulic Permit Application [HPA] database, US Army Corps of Engineers maps and records). Further information may be acquired and incorporated from local biologists or notes from stream surveys that can prove valuable in identifying revetments or other impacts that are difficult to identify from aerial photos, maps, and those that may have occurred outside the HPA process.
Information from the SSHIAP system can be used for answering the question “how much habitat is in a degraded state from ditching, dredging, dike construction, removal of riparian vegetation or other human activities in or adjacent to salmon habitats?”
Examples of hydromodifications:
SSHIAP hydromodification coverage. Red indicates dike/levee; turquoise indicates ditching.