Engineered (structural) debris-flow mitigation for all creeks with elements at risk and subject to debris flows is often outside of the financial capability of the regulating government, and heavy task-specific taxation may be politically undesirable. Structural debris-flow mitigation may only be achieved over long (decadal scale) time periods. Where immediate structural mitigation is cost-prohibitive, an interim solution can be identified to manage residual risk. This can be achieved by implementing a debris-flow warning system that enables residents to reduce their personal risk for loss of life through timely evacuation. This paper describes Canada's first real-time debris-flow warning system which has been operated for 2 years for the District of North Vancouver. The system was developed based on discriminant function analyses of 20 hydrometric input variables consisting of antecedent rainfall and storm rainfall intensities for a total of 63 storms. Of these 27 resulted in shallow landslides and subsequent debris flows, while 36 storms were sampled that did not reportedly result in debris flows. The discriminant function analysis identified as the three most significant variables: the 4-week antecedent rainfall, the 2-day antecedent rainfall, and the 48-h rainfall intensity during the landslide-triggering storm. Discriminant functions were developed and tested for robustness against a nearby rain gauge dataset. The resulting classification functions provide a measure for the likelihood of debris-flow initiation. Several system complexities were added to render the classification functions into a usable and defensible warning system. This involved the addition of various functionality criteria such as not skipping warning levels, providing sufficient warning time before debris flows would occur, and hourly adjustment of actual rainfall vs. predicted rainfall since predicted rainfall is not error-free. After numerous iterations that involved warning threshold and cancelation refinements and further model calibrations, an optimal solution was found that best matches the actual debris-flow data record. Back-calculation of the model's 21-year record confirmed that 76% of all debris flows would have occurred during warning or severe warning levels. Adding the past 2 years of system operation, this percentage increases marginally to 77%. With respect to the District of North Vancouver boundaries, all debris flows occur during Warning and Severe Warnings emphasizing the validity of the system to the area for which it was intended. To operate the system, real-time rainfall data are obtained from a rain gauge in the District of North Vancouver. Antecedent rainfall is automatically calculated as a sliding time window for the 4-week and 2-day periods every hour. The predicted 48-h storm rainfall data are provided by the Geophysical Disaster Computational Fluid Dynamics Centre at the Earth and Ocean Science Department at the University of British Columbia and is updated every hour as rainfall is recorded during a given st...

There are a number of geomatics tasks required to support a Geohazard Management Program (Program). For the program implemented by BGC Engineering Inc. for several midstream pipeline operators, these tasks range from identification of potential geohazards (landslide, river erosion), to setup and support for field navigation, through to geohazard database management. Doing these in an efficient and effective manner requires substantial amounts of spatial data and a toolset containing both software and hardware components. For this Program geohazards are classified as hydrotechnical (e.g. a pipeline crossing a river) or geotechnical (e.g. a pipeline traversing a slope). Lists of potential geohazards are generated and provided to field crews who then navigate to each site and perform a field inspection. Navigation and inspection observations are accomplished with the aid of a ruggedized laptop connected to wireless GPS. Upon return from the field, sites are uploaded to Cambio™, an internet database for managing geohazards. Each site is assigned a frequency of action commensurate with the estimated level of risk. Assigned actions include follow-up ground inspections, detailed investigations, monitoring, maintenance and mitigation. An audit trail of site inspections, surveys and mitigation reports, photos, and site survey drawings, are all available for review within Cambio™, allowing access to the information from any site with an internet connection. This paper will present an overview of the Geohazard Management Program from a geomatics perspective, highlighting the integration of geomatics tools into a system designed to be used by engineering personnel, field technicians, and project managers.