Mining subsidence in the Bogdanka coal mine—reaching three meters—intensifies runoff and local flood hazards in low‑gradient terrain. Using high‑resolution LiDAR DEMs and SCS‑CN runoff modelling, we quantified runoff changes during extreme precipitation in 2018 and 2024. Runoff increased by up to 12.6% in maximally subsiding zones, while reference areas showed minimal change, demonstrating the value of integrating terrain deformation into flood‑risk assessment.