Spatio-temporal differentiation characteristics and scenario predictions of water resources carrying capacity in Shaanxi Province

Analyzing the spatiotemporal characteristics and scenario predictions of water resources carrying capacity (WRCC) provides a vital scientific basis for water resources planning and management. To address the pronounced regional disparities across Shaanxi Province from south to north and the limitations of traditional static evaluation methods, this study selected the 10 prefecture-level cities in the province as research units. A comprehensive evaluation system was established encompassing four dimensions: socioeconomic development, water resources demand, environmental response, and water resources supply. By integrating principal component analysis, the obstacle degree model, and the system dynamics model, this research conducted a dynamic evaluation of WRCC from 2014 to 2023, identified key obstacle factors, and predicted WRCC dynamics under the four scenarios (i.e., baseline scenario, coordinated transformation scenario, climate risk scenario, and water-saving priority scenario) for the period 2024-2030. The results were as follows: (1) On the temporal scale, the intensity of socioeconomic activities, the balance between water supply and demand, and the ecological water demand were the three principal components affecting WRCC in Shaanxi Province from 2014 to 2023, with a cumulative contribution rate of 91.33%. The comprehensive WRCC score has shifted from negative to positive and gradually increased, whereas the potential for water resources development and utilization has continued to decline. On the spatial scale, WRCC in central Shaanxi (excluding Baoji and Xianyang cities) has declined markedly, WRCC in northern Shaanxi has deteriorated rapidly, and WRCC in southern Shaanxi has exhibited a fluctuating downward trend. (2) The five most significant obstacle factors and their frequencies were total water resources (49%), annual runoff depth (44%), gross domestic product (42%), total groundwater resources (36%), and permanent population (35%). (3) Due to the baseline scenario continuing the current development model, the coordinated transformation scenario focusing on green economic transformation and multifactor collaborative optimization, the climate risk scenario accounting for the impact of extreme climate with reduced total water resources, and the water-saving priority scenario emphasizing water conservation in agricultural, industrial, and domestic sectors, the average comprehensive WRCC scores of the 10 prefecture-level cities in Shaanxi Province under the four scenarios have changed from -3.12, 3.15, -4.98, and 3.10 in 2023 to 2.76, -2.39, 3.80, and -2.00 in 2030, respectively. Only the coordinated transformation scenario and the water-saving priority scenario have led to improved WRCC. In contrast, under the baseline scenario, the average water resources development and utilization rates in central Shaanxi (Xi’an 55%, Xianyang 68%, and Weinan 99%) and northern Shaanxi (Yulin 53%) exceeded the 40% threshold, indicating that WRCC in these cities is overloaded. By targeting key water-saving areas in central Shaanxi, including agriculture (reducing irrigation water use by 30% per unit area) and industry (reducing water consumption by 35%), the water-saving priority scenario has reduced water utilization rates in the three cities to 45%, 56%, and 63%, significantly easing pressure on the water resources system and improving WRCC. However, due to rigid constraints on water use in the energy industry in northern Shaanxi, short-term water-saving effects remain limited. Overall, these findings provide quantitative evidence for understanding the evolution of regional WRCC in Shaanxi Province and offer a scientific basis for differentiated water resources management.