Flood Vulnerability Assessment under Subsidence-Influenced Terrain Using Deformation-Adjusted DEM in an Oil and Gas Field

Flood hazards in arid oil-producing regions are significantly influenced by both natural hydrological processes and terrain changes resulting from subsidence. This study develops a deformation-adjusted approach to flood risk assessment for the Yibal field in the northern part of the Sultanate of Oman, where long-term hydrocarbon production has led to measurable ground deformation. A high-resolution digital elevation model (DEM) from an aerial survey in 2013 was adjusted using cumulative surface deformation data (2013–2023) derived from PS-InSAR measurements. By subtracting the surface deformation from the baseline DEM, an updated DEM for 2023 was produced that explicitly incorporates subsidence into hydrological modeling. Weighted flood risk mapping was then performed using slope, precipitation, land use/land cover, and drainage parameters. Results show a marked increase of flood vulnerability, with high- to very high-risk zones (8.0-8.6, 8.7-9.6) expanding in areas affected by surface deformation. These findings demonstrate that conventional flood risk mapping, which neglects subsidence, can underestimate hazard levels in petroleum fields where ground deformation alters drainage pathways. Incorporating subsidence-adjusted terrain data into hydrological risk assessment provides more realistic flood susceptibility maps, improving early warning, infrastructure protection, and sustainable petroleum field management. Beyond the Yibal field, the method is transferable to other petroleum basins and arid regions where subsidence interacts with surface hydrology.