Technology to Monitor River Scour Exposure of Oil and Gas Pipelines

Hazardous liquid pipelines are mandated to maintain a minimum cover depth below the river bottom at crossings of inland bodies of water with widths greater than 30 m (100 ft) from high water mark to high water mark as per United States Federal Regulation 49 CFR Part 195.248, Subpart D—Construction. These prescribed installation depths apply during the initial pipeline construction phase and not during system operation. Over time, river scour results in a reduction in the prescribed depth of cover that can compromise the pipelines. This research involved development of a River Scour Monitoring System (RSS) to benefit society by serving as an active monitoring system capable of determining the degree of scour in a riverbed thereby alerting pipeline operators should the amount of cover of the pipeline become reduced. The technology used was based on a temperature gradient decay method for monitoring a subject pipeline river crossing for scour conditions. Field demonstrations at three crossing sites provided a validation of the applicability for detecting depletion of cover above an installed pipeline.