City of Port Moody Landslide Forensics

In late January of 2018, a significant rainfall event occurred where approximately 87 mm of rain fell during a two day rain event, resulting in several small landslides in the Lower Mainland.  On a creek bank in the southwest area of  Port Moody, saturated soils and concentrated surface water draining from the top of the creek bank resulted in a 100 cubic meters mudslide.  The debris path stretched 80 m downstream, plugged storm systems, and discharged debris and sediment laden water on to the road surface.  Terran Geotechnical Consultants Ltd. was retained by the City of Port Moody to assess the landslide and review the safety of residential buildings along the ravine corridor.  In addition, we completed a post failure analysis to determine the causes of the failure.  Terran Geo provided recommendations and designs for managing concentrated flows and remediating the failed slope.