Characteristic analysis and potential hazard assessment of reclaimed mountainous areas in Lanzhou, China

Abstract

The limited available land and unique geomorphological features of the Loess Plateau have restricted the urbanization process, causing the spread of land reclamation (LR). This study examined the city of Lanzhou using remote sensing, statistical methods and a numerical model to analyze the distribution law and the potential disaster impact within the LR areas to suggest prevention and control measures. The results showed that the numbers of 93 LR can be divided into remove-mountaintop (RM), cut-one-side-slope (COSS) and cut-both-side-slopes (CBSS), and their numbers increased from 2000 to 2010, thereafter decreasing; a good exponent relationship was also observed between land creation area and excavation volume. A large number of LR areas are distributed on both sides of the Yellow River, which can potentially generate more mudflows and cause huge economic losses and casualties, especially in the core urban areas. A positive exponential relationship was found between the mudflow volume and accumulation area in the simulation results and the statistical data, and the fitting results were generally similar. The mudflow impact scale, simulated using a modified LAHARZ model, was found to be reliable. The analysis of disaster risk demonstrates that the potential hazards of LR are both preventable and controllable and that a focus on long-term risk is required. This study aims to support geological disaster prevention, control and emergency management.