Risks to Marine Pipelines From Drifting Ice: Gathering the Evidence

Marine pipelines in ice-prone waters are exposed to a number of environmental threats that do not exist in warmer waters. Of particular concern is the damage from ice features such as pressure ridges that drift into shallow areas. The ice keel comes in contact with the seabed and, as the ice feature keeps drifting, it may gouge the seabed to some depth and for considerable distances. Trenching and burial are seen as the best means of protecting these structures, but adequate depth relies on adequate knowledge of these events. This is obtained in various ways. Actual, real-scale events provide valuable information. Seabed mapping allows an appreciation of gouging activity in the target sector. Physical experiments can generate a nearly complete picture of these events, and can be used to validate numerical models. A description is presented of an abandoned marine pipeline in Northern Canada, which represents a rare test case scenario. Plans to conduct field investigations on that pipeline are being considered.