Causes for flood damage in Shitingjiang River crossing section of Lanzhou-Chengdu Pipeline

The Shitingjiang River crossing section of the Lanzhou-Chengdu Pipeline experienced an unprecedented flood in northwest Sichuan Province. As a result, the pipeline was washed out and broken. To find out root causes for such flood damages, rationality in design stages is reviewed. In addition, direct and root causes for the pipeline breaking are analyzed. The results show that continuous consolidation of dams for Renmin Canal induced undercutting of the riverbed. Accordingly, the Shitingjiang River crossing section was exposed gradually and suffered from flood damages. Since buildings (structures) on water may have significant impacts on oil and gas pipelines, sufficient attentions shall be paid during design and operation stages. Accordingly, suggestions and requirements for restoration of the pipeline are proposed: (1) detailed geologic surveys shall be performed for areas with crossing of pipelines; (2) cares shall be taken for specific features of rivers to be crossed and related various risks to identify the optimal section for crossing; and (3) sufficient attentions shall be attached to impacts that sand excavation, quarrying, mining and other human activities may have to river channels.