Earth Observation: Watercourse Morphological Change Detection

Infrastructure crossing rivers or water courses are subject to a variety of hydrotechnical hazards. Extreme flood events are associated with bank erosion, riverbed degradation, or the formation of new channels (avulsion). For buried pipelines, flood events could reduce the depth of cover (DoC), potentially resulting in pipeline exposure and failure due to water or debris loading. Consequently, the proactive monitoring of changes in river morphological characteristics over time supports the identification of hazards posed by fluvial processes and active channel dynamics.​

Morphological changes of water courses over time, or in response to flood events, are typically observed during ground inspections or helicopter surveys. The timing of these surveys is often a result of planning made months or years in advance, or in response to known high-flow events. To facilitate monitoring between scheduled surveys and to inform the need for event-triggered site visits, BGC’s flood monitoring program allows users to determine whether a significant flow event has likely occurred at river crossings of interest using hydrometric data. However, not all rivers have appropriate hydrometric stations from which real-time information about the river can be inferred.​

The proliferation of satellite-based remote sensing instruments, capturing high resolution data with frequent revisit capability, implies that operational monitoring of river state variables is possible. The satellite observations facilitate cost-effective data acquisitions over large areas, allowing examination of the full range of spatial and temporal variations in river systems in a quantitative manner. By exploiting these datasets, BGC can identify hydro-morphological changes in a quantitative way to support risk-informed decision making in areas where real-time hydrometric data is unavailable.​