Bio Assessments

Rapid Bio-Assessment

The Council worked with Oregon Department of Fish and Wildlife (ODFW) and a qualified contractor to conduct aquatic habitat inventories and a rapid bio assessment (RBA) of approximately 50 stream miles in Milton Creek, as well as North and South Scappoose Creeks.

Aquatic Habitat inventories are a way to assess the quality and type of habitat present in a stream system. Aquatic habitat inventories interpret a large amount of data pertaining to the stream characteristics. The data collected includes (but not limited to); type of channel substrate, classification of reaches into types of pool, riffle, glide, cascade, and beaver dams. There is also a large amount of collateral data collected; percent shade, composition of riparian area etc. This type of information is very useful for restoration projects.

The (RBA) or Rapid Bio-Assessment protocol is a scientific method to gather data on fish distribution and potential barriers to fish on a watershed scale. The surveys continue upstream to the end of fish distribution. As the surveyor moves upstream the contractor snorkels every 5th pool and describes the number and species of salmonid present, as well as any potential barriers along the route. The RBA protocol then takes this sample of the watershed and uses that to estimate adult salmonid use of the watershed and how much potential the watershed has of supporting more juvenile salmonid. This set of surveys (RBA), and (Aquatic Habitat Inventory) provides information on current use of the stream by salmonid, habitat conditions, and identify limiting factors to spawning and rearing in the watershed. The final report provides details on each of the creeks that were surveyed.