Natural Hazard and Risk Management for South American Pipelines

Abstract

Hazard identification and rating involve the first two of a four-phase natural hazard and risk management (NHRM) system that is being developed to manage natural hazards along linear facilities. In Canada, completing these first two phases is generally straightforward. Baseline data including air photos, geology and topographic maps are readily available; the number and types of hazard exposure are often limited for any given facility; and, the standard of care expected during design and construction is understood and practiced. The NHRM methodology is also being applied on South American pipelines. Greater flexibility is required in obtaining necessary input data. Helicopter and vehicle access are often more limited, and greater reliance must be placed on airphoto interpretation and literature review. Processes of rating hazard exposure are needed for less familiar hazard types, including tsunami, volcanic eruption, and tectonic ground rupture. South American construction and design practices must be accounted for in the rating methodology. Using examples from recently constructed trans Andean pipelines, this paper outlines application of the NHRM system to linear facilities located in areas of diverse hazard exposure and less stringent design and construction practices. Under the broad headings of ‘geotechnical’ and ‘hydrotechnical’ hazards, a methodology for rating eleven different hazard types is outlined. On the geotechnical side, these include tsunami, volcanic eruption, tectonic ground rupture, landslides and debris flows originating off-rights-of-way, and mass movements originating on rights-of-way. Hydrotechnical hazards include scour, degradation, bank erosion, encroachment, and channel abandonment/avulsion.