This recommended practice (RP) applies to new and existing hydrocarbon pipelines that transport gas and hazardous liquids. It is intended to apply to onshore waterways and coastal zones that may be susceptible to hydrotechnical hazards. An onshore waterway is any man-made or natural channel through which water flows. Coastal zones extend offshore to a water depth of 15 ft and extend inland to include those areas of land influenced by tidal action, storm surge, back-water flooding, and other coastal hazards. This RP provides guidelines and recommendations for identifying, assessing, and managing risks to pipeline integrity associated with these hazards through the life cycle of a pipeline. Except for the design and construction provisions in Section 7 of this RP, which are strictly for new pipelines, this RP is for both existing and new pipelines.