Spatiotemporal Evaluation of Multi-Dimensional Water Resources Carrying Capacity in China’s Seventh Largest Desert

The Kubuqi Desert, China’s seventh-largest desert, is characterized by a severe water supply–demand imbalance and ecological fragility. This study conducted a multi-dimensional dynamic evaluation of the water resources carrying capacity (WRCC) of the desert and its subordinate banners using the TOPSIS model with game theory-based combined weighting. The main obstacle factors were subsequently identified via the obstacle degree model. The results indicated that the comprehensive WRCC index increased from 0.351 in 2010 to 0.584 in 2023, showing a stepwise upward trend. The WRCC grade gradually shifted from Grade II in 2010 to Grade III in 2023. The ecological environment and socioeconomic conditions subsystems improved most markedly, with their contributions to the comprehensive WRCC increasing year by year. The water resources subsystem fluctuated within a narrow range and remained largely at Grade III. The WRCC of each banner exhibited significant spatiotemporal heterogeneity, forming a spatial pattern of “high in the east and low in the west”. WRCC values were ranked in descending order as Jungar Banner, Dalad Banner, and Hangjin Banner, with multi-year averages of 0.541, 0.516, and 0.492, respectively. From 2010 to 2014, all banners except Jungar Banner remained in an overloaded state for most years. Since 2015, the carrying status of each banner has generally improved alongside rising WRCC, and the entire region has reached a critically bearable state. The main obstacle factors constraining WRCC included the ecological water use rate, soil erosion rate, water supply modulus, aridity index, water conservancy and environmental investment rate, water resources exploitation rate, water quality compliance rate in water function zones, water use per 104 CNY GDP, and forest coverage rate. Among these, three belonged to the water resources subsystem, four to the ecological environment subsystem, and two to the socioeconomic conditions subsystem, indicating that socioeconomic indicators exerted the weakest restrictive effect on WRCC. Future WRCC development and governance should adhere to the rigid constraints of water resources, prioritize the optimization of the industrial structure and urban layout, implement targeted soil erosion control, and steadily increase forest coverage, thereby promoting the green, low-carbon, and efficient development of the Kubuqi Desert.