In the analysis of river regimes, bankfull discharge is one of the most important indicators of stream flow. Bankfull is the critical channel forming discharge. The frequency of recurrence of bankfull discharge indicates the risk of flooding. This study tests the variability in bankfull discharge recurrence intervals for different land use/land cover categories in the Pacific Northwest. Bankfull discharge recurrence intervals determined from field data and stream flow records collected for 82 streams, USGS land use/land cover data, and USGS digital elevation models were analyzed using ArcView GIS, ArcView Spatial Analyst with the Hydrologic Modeling extension, and ARC/INFO.