Assessment and early warning of the coupled carrying capacity of water resources, environment, and ecology: A case study of Ordos

Water resources, water environment, and water ecology are interrelated and mutually influential, playing a critical role in integrated water system planning and high-quality economic development. Three-dimensional water system (water resources, environment, and ecology) carrying capacity (TDWCC) is crucial to regional development and sustainable growth. This study established a Driving–Pressure–State–Impact–Response (DPSIR) model and coupled it with the deal solution similarity ranking technique (TOPSIS) to evaluate the TDWCC in Ordos. By integrating entropy weight with variable weight, the comprehensive indicator weights are determined for assessing TDWCC. Based on TDWCC status and potential future trends, the risk of TDWCC in 2030, 2040, and 2050 is predicted. The results indicate that the overall TDWCC in Ordos increased from 0.35 in 2000 to 0.59 in 2023 indicating a slightly weak carrying capacity. Kangbashi District saw rapid improvement due to better infrastructure and water management policies. From 2016 to 2023, its TDWCC grade increased from Grade III to Grade IV. In contrast, Jungar Banner consistently remained at Grade II or Grade III due to limited water resources and high industrial water consumption. Among the five subsystems, the pressure and impact subsystems exhibit relatively high carrying capacity. In 2030, TDWCC temporarily declines to 0.51, elevating the warning level to serious warning. In 2040 and 2050, it is projected to rise to 0.63 and 0.68 respectively, entering the mild warning range. The key driver of TDWCC in Ordos is ecological flow satisfaction, green area coverage and water use per unit of industrial value added (in RMB 10,000). In the future, efforts to enhance regional water resource carrying capacity should focus on optimizing the spatial allocation of water resources, adjusting water use structures, improving ecological regulation capacity, and strengthening the water governance system. The findings of this study provide decision-making support for the sustainable utilization and zoned management of water resources in Ordos, and offer theoretical guidance for water ecological governance in resource-constrained cities.