Landsliding in the United States causes an average of 25 to 50 deaths and $1 to $2 billion in economic losses annually (Schuster and Fleming, 1986). In Oregon, a minimum estimated $4 million in damage occurs annually (Wold and Jochim, 1995). This estimate for landslide damage in Oregon was calculated from 1973-1983 data and is growing due to the ever-increasing pressure for development in areas of geologically hazardous terrain inside urban growth boundaries (Wold and Jochim, 1995). During 1996 and 1997, heavier than normal rains caused over 700 landslides in the Portland Metropolitan area which totaled over $40 million for mitigation (Burns et al., 1998).
The purpose of this study is to investigate the engineering geology and relative slope stability of the southern half of Newell Creek Canyon, Oregon City, Oregon and to create a relative stability map of this area. The study area is located in Oregon City along the southeastern border of the Portland Metropolitan Region in northwestern Oregon. This particular study area was chosen for it’s extensive landslides and the opportunity to improve on earlier slope stability studies. Since part of the study area is within Portland’s urban growth boundary, I believe this thesis will help the community in making educated future development decisions.