A recent pipeline failure in the San Jacinto River Valley, Texas, was caused by riverbed erosion. As a result the Research and Special Programs administration Office of Pipeline Safety, United States Department of Transportation (USDOT), began researching the effects of natural hazards on pipelines. Through interagency cooperation, the Federal Emergency Management Agency (FEMA) and its contractor, Michael Baker Jr., Inc., provide research services, data, and facilities to USDOT. Risk assessment of natural hazards will enable the USDOT to direct its efforts to those parts of the national pipeline infrastructure where they will have the greatest impact. The purpose of this study is to identify ten priority areas of the national pipeline infrastructure that present both high probability of failure due to natural disasters, and high consequences in the event of failure. This paper presents the results of a nationwide riverbed erosion risk assessment study, using a potential scour depth model, developed by Williams et al (1992). ArcInfo is used to perform the analysis. Potential scour depth is computed using the 100-year peak discharge, sediment size, and a factor describing stream characteristics. this factor is derived from the length of the stream and the Euclidean distance between the nodes. the scour depth is converted to a continuous surface raster file with a one-square kilometer resolution. This is overlaid with another raster file that contains streams and three classes of annual flooding probability. The results show erosion hazard defined as potential scour depth within streams and flood plains, associated with annual flooding probability. By overlaying the erosion hazard with the pipelines, pipeline segments that present a high erosion risk are identified.
The paper presents SITRAS 2 system functionality, current user experience, and future plans. The system is made to help organize, analyse, and manage the vast amount of data for Statoil's offshore/onshore pipeline network. SITRAS 2 provides an integrated solution where the end user is given a total operational overview of the condition and observations of all pipelines. Further, the system is a tool which will help the exchange of experience between current operations and new pipeline projects. The system plays an important part of the company's contingency planning and as a management decision tool for optimal inspection/maintenance programs and future investments. The system uses ArcView as the main user interface, Oracle database, Oracle Grafh for report generation, ArcInfo for generating the geographical database, and IEF from Texas Instruments for mass registration and maintenance.