Assessment of terrain susceptibility to thermokarst lake development along the Qinghai–Tibet engineering corridor, China

Thermokarst lakes have been developing recently along the Qinghai–Tibet engineering corridor in association with increased human activity and persistent climatic warming. Based on field observations, we assessed the susceptibility of terrain to the development of thermokarst lakes between the Chumaerhe River and Fenghuoshan mountain pass. A susceptibility map of the region was created in a geographic information system by assessing seven controlling factors, ranked using the analytic hierarchy process. The resulting susceptibility values ranged between 0.1 and 0.66. These susceptibility values were divided into four classes (high, moderate, low, and lowest) according to the mutagenesis point method. Areas with values between 0.1 and 0.16 were considered to have the ‘lowest’ susceptibility, while those between 0.26 and 0.66 were considered to have ‘high’ susceptibility. Using SPOT-5 satellite data, we determined that the high-susceptibility areas contained approximately 91 % of the total thermokarst lake area in the study region, and 88 % of the number of lakes. The moderate, low, and lowest level areas accounted for about 52 % of the study region, but only contained 9 % of the total lake area and 12 % of the lakes. Finally, relations between the area of the thermokarst lakes and the main controlling factors, e.g., ground ice content, ground temperature, vegetation type, and altitude were discussed.