Heping Shu

Arid and semi-arid resource-based industrial cities often face limited water supply, high water demand, and pollution pressure. Using Baiyin City in northwest China as a case, this study assesses water resources carrying capacity (WRCC) with an integrated analytical approach. The indicator system includes 16 indicators covering water resources, population, economy, and water environment. Combined AHP–entropy weighting is used to determine indicator weights. The cloud model is used for grade classification, and a system dynamics (SD) model is used to compare development scenarios. Historical assessment covers 2014–2023, while scenario simulations cover 2024–2035. Per capita water resources (X1), the water resources development and utilization rate (X5), and COD discharge (X15) receive the highest combined weights, accounting for 37.049% of the total weight. WRCC increased from 0.371 in 2014 to 0.635 in 2023, and the grade improved from Grade IV to Grade II, although the trend fluctuated during 2019–2021. By 2035, simulated WRCC reaches 0.705 under the water-saving scenario, 0.655 under sustainable development, 0.643 under natural development, and 0.596 under economic development. Under the scenario settings used in this study, water saving and pollution control lead to higher WRCC values than economic expansion alone.

The surface water quality issue in arid regions is becoming increasingly severe and has become a significant challenge for global environmental protection and water resource management. By continuously collecting surface water samples (2000~2024) and utilizing hydrochemical and principal component analysis, the changes in the chemical composition of surface water and its water quality pollution characteristics are examined in the Shiyang River Basin. The surface water anion concentrations are characterized by HCO₃⁻ > SO₄²⁻ > Cl⁻, with average concentrations of 214.11 mg/L, 117.31 mg/L, and 21.61 mg/L, respectively. The cation concentrations follow the trend of Ca²⁺ > Mg²⁺ > Na⁺ > K⁺, with average concentrations of 56.22 mg/L, 33.75 mg/L, 22.91 mg/L, and 5.33 mg/L, respectively. The dominant water types are Ca-HCO₃ and Ca (Mg)-HCO₃ in the mountainous area and in the plains, respectively. The weathering of carbonates and silicates is the main controlling factor for the evolution process of surface water. Strong evaporation leads to significant differences in ion concentrations, which is manifested as low in mountainous areas and high in plain areas. In addition, the surface water quality in the plains is worse than that of the mountainous areas. The main pollution indicators include DO, CODM_n, COD, BOD₅, NH₄⁺-N, TP, TN, and fecal coliforms. The surface water quality of Hongyashan Reservoir and Caiqi has improved significantly, reflecting the impact of the water diversion project. The results of this study are of great significance for improving water resource management and ensuring the sustainability of the ecological environment in arid regions.

Engineered loess-filled gullies, which are widely distributed across China’s Loess Plateau, face significant stability challenges under extreme rainfall conditions. To elucidate the regulatory mechanisms of antecedent rainfall on the erosion and failure processes of such gullies, this study conducted large-scale flume experiments to reveal their phased erosion mechanisms and hydromechanical responses under different antecedent rainfall durations (10, 20, and 30 min). The results indicate that the erosion process features three prominent phases: initial splash erosion, structural reorganization during the intermission period, and runoff-induced gully erosion. Our critical advancement is the identification of antecedent rainfall duration as the primary “pre-regulation” factor: short-duration (10–20 min) rainfall predominantly induces surface crack networks during the intermission, whereas long-duration (30 min) rainfall directly triggers substantial holistic collapse. These differentiated structural weakening pathways are governed by the duration of antecedent rainfall and fundamentally control the initiation thresholds, progression rates, and channel morphology of subsequent runoff erosion. The long-duration group demonstrated accelerated erosion rates and greater erosion amounts. Concurrent monitoring demonstrated that transient pulse-like increases in pore-water pressure were strongly coupled with localized instability and gully wall failures, verifying the hydromechanical coupling mechanism during the failure process. These results quantitatively demonstrate the critical modulatory role of antecedent rainfall duration in determining erosion patterns in engineered disturbed loess, transcending the prior understanding that emphasized only the contributions of rainfall intensity or runoff. They offer a direct mechanistic basis for explaining the spatiotemporal heterogeneity of erosion and failure observed in field investigations of the engineered fills. The results directly contribute to risk assessments for land reclamation projects on the Loess Plateau, underscoring the importance of incorporating antecedent rainfall history into stability analyses and drainage designs. This study provides essential scientific evidence for advancing the precision of disaster prediction models and enhancing the efficacy of mitigation strategies.

Water ecological security is intricately connected to regional economic development and human survival, exerting a profound influence on regional sustainability. Water ecological security in the study area is a matter of urgency. In this study, the socio-economic, ecological, and water resource data of five cities in the west of the river from 2006 to 2021 are used to construct a dynamic model of the regional water ecological security system and simulate the trend of the regional water ecological security from 2022 to 2035, and the results indicate the following: (1) From 2006 to 2021, Hexi Corridor’s economy exhibited a significant upward trend, while its total population experienced a marked decline. Indicators for the ecological environment system showed notable improvement, whereas those for the water resource system demonstrated a significant downward trend. (2) Spatially, the mean values of system indices in the southeast and northwest regions were higher than those in the central region. (3) Between 2022 and 2035, projections reveal that the total GDP, industrial added value, average sewage discharge, urban green space, and water consumption for ecological purposes will all trend upward. Concurrently, the total population, total water supply, and total water demand are expected to exhibit a continuous decline. (4) The comparative comprehensive scores of the scenario models are as follows: EPS (2.18) > RSS (1.57) > CDS (1.15) > EDS (1.08). This analysis provides valuable insights into the dynamics of water ecological security in the Hexi Corridor and offers critical guidance for sustainable regional development planning.

Considering the possibility of increasing water supply in China in the short term and the long-term threat posed by shrinking glaciers, this paper studied the spatiotemporal evolution of runoff in typical arid areas and the influence of hydrometeorological elements on runoff, aiming to clarify the hydrological cycle law and provide a basis for adjusting water resource management strategies to cope with future uncertain changes. Based on hydrological data from 1956 to 2020, the spatial and temporal variation in runoff were discussed by means of wavelet analysis, MK test, RS analysis, and spatial interpolation. The influencing factors of runoff evolution in the Shule River Basin were determined. The results showed that the runoff in the Shule River Basin showed an increasing trend in the past 60 years. Five hydrological stations (Changmabao Station, Panjiazhuang Station, Shuangtabao Reservoir, Dangchengwan Reservoir, and Danghe Reservoir) were selected as the research objects. Among them, the runoff of Changmabao Station increased the most, which was 1.202 × 10⁸ m³/10 a. Future projections suggest a continued rise in runoff, particularly at Shuangtabao Reservoir. The runoff exhibited positive persistence and varying degrees of mutation, with most mutations occurring in the early 21st century. The runoff in the basin has a periodicity of multiple time scales (there are 2–3 main cycles), and the main cycle of annual runoff is concentrated in 58 years. This comprehensive analysis provides valuable insights for the sustainable management of water resources in inland river basins amidst changing environmental conditions. The spatial variation in runoff in summer and autumn and the whole year showed a significant southeast to northwest decreasing pattern. During the study period, accelerated glacier melting caused by rising temperatures had the most significant impact on runoff change (p < 0.01), and the upstream of the study area also complied with this rule (temperature contribution rate [25.96%] > precipitation contribution rate [23.91%]). The contribution of temperature and precipitation changes caused by human activities in the middle stream to runoff was relatively large, which showed that the contribution rate of temperature in Guazhou Station to runoff was 34.23% and the contribution rate of precipitation in Dangchengwan to runoff was 60.27%. The research results provide a scientific basis for the rational and efficient utilization of water resources in the arid area of Northwest China.

The consequence of climatic change and anthropogenic environmental modifications is a notable diminution in runoff across arid and semi-arid regions. For the sustainable management of regional water resources, it is crucial to comprehend the impacts of climatic and anthropogenic factors on runoff patterns. The Zuli River was designated as the study area for this study, and the Mann–Kendall test, double cumulative curve method, slope change ratio of cumulative quantity method, and elasticity coefficient method were employed to identify mutation points and to quantify the relative impacts of climatic variation and human activities on runoff. The results revealed a statistically insignificant downward trend in mean annual precipitation, a significant declining trend in runoff, and an evident increasing trend in potential evapotranspiration and temperature between the years 1957 and 2019. The analysis revealed that the point of sudden change in runoff at Huining station occurred in 1992, whereas the mutation point at Guo Chengyi station was identified in 1985 and that at Jingyuan station in 1995. The contribution of climate change to runoff was found to range from 28.7% to 58.5%, while the contribution of human activities to runoff ranged from 41.5% to 71.3%, based on different methodologies. Therefore, human activities were recognized as the main factor affecting the variations in runoff within the Zuli River Basin, while climate change acts as a secondary contributor. The results of the study hold considerable importance for enhancing the scientific understanding of hydrological processes within the basin and for guiding regional water administration strategies.

Water shortages are serious in northwest China due to the level of social and economic development, engineering, resource shortages, and other factors being restricted, so the conflict between supply and demand for water resources is prominent in different regions and different water use sectors. Therefore, Pingliang City was selected as the research object in this study. The membership function was introduced, and an interactive algorithm to correct model parameters based on the fairness constraint was derived. An uncertain multi-objective fuzzy programming model was also established. The results show that the optimal allocation of water will be 38,051.9~40,740 × 10⁴ m³ and 39,938.4~41,317.5 × 10⁴ m³ under a normal year (p = 50%) and a dry year (p = 75%) in 2025, respectively, and the corresponding water shortage rates will be 4.2% and 6.7%. In 2035, the optimal water allocation will be 45,644.1~49,245.9 × 10⁴ m³ and 46,442.4~50,044.2 × 10⁴ m³ and the water shortage rates will be 7.0% and 7.0%, respectively. The proportion of groundwater supply will decrease by 8.8% and 13.8% in 2025 and 2035 after the optimal allocation, the proportion of surface water supply will increase by 9.6% and 12.2%, and the proportion of reclaimed water will increase by −0.78% and 2.1%, respectively. The results can provide a technical reference for the development and utilization of water resources in other cities and similar areas in semi-arid regions.

Although numerous models have been employed to address the issue of landslide susceptibility at regional scale, few have incorporated landslide typology into a model application. Thus, the aim of the present study is to perform landslide susceptibility zonation taking landslide classification into account using a data-driven model. The specific objective is to answer the question: how to select reasonable influencing factors for different types of landslides so that the accuracy of susceptibility assessment can be improved? The Qilihe District in Lanzhou City of northwestern China was undertaken as the test area, and a total of 12 influencing factors were set as the predictive variables. An inventory map containing 227 landslides was created first, which was divided into shallow landslides and debris flows based on the geological features, distribution, and formation mechanisms. A weighted frequency ratio model was proposed to calculate the landslide susceptibility. The weights of influencing factors were calculated by the integrated model of logistic regression and fuzzy analytical hierarchy process, whereas the rating among the classes within each factor was obtained by a frequency ratio algorithm. The landslide susceptibility index of each cell was subsequently calculated in GIS environment to create landslide susceptibility maps of different types of landslide. The analysis and assessment process were separately performed for each type of landslide, and the final landslide susceptibility map for the entire region was produced by combining them. The results showed that 73.3% of landslide pixels were classified into “very high” or “high” susceptibility zones, while “very low” or “low” susceptibility zones covered only 3.6% of landslide pixels. The accuracy of the model represented by receiver operating characteristic curve was satisfactory, with a success rate of 70.4%. When the landslide typology was not considered, the accuracy of resulted maps decreased by 1.5~5.4%.

Slope failure is a one of major process that causes severe landform variation and environment variation, and slope failure has become a major hidden danger to human settlement and urban construction in this vast loess region. The physical model of slope failure as induced by artificial rainfall was constructed in the field, and monitored the pore water pressure (PWP), earth stress (ES), volumetric water content (VWC), electrical conductivity (EC), and temperature (T) of the soil using this physical simulation. The surface morphology of slope started to occur in the slope as a result of erosion caused by rainfall and rainwater infiltration at the beginning of the experiment; concurrently, PWP, ES, VWC, and EC were increased gradually. Meanwhile, the saturated weight of the soil rose. In the middle of the experiment, PWP, ES, VWC, and EC were increased rapidly as the artificial rainfall continued, and the ratio of soil pore the soil fell. The slope landform was obviously occurred during the experiment, when it was noted that PWP, ES, VWC, and EC of the soil rapidly decreased. Afterwards, slope failure evolved into a debris flow; eventually, the landform was entirely changed in the slope. The soil became more compact toward the end of the experiment, and PWP, ES, VWC, and EC were slowly increased; these factors indicated that the loess slope was temporarily stable. This study could potentially be used to provide the relevant parameters for numerical simulations of landform variation in loess regions, and provide reference for regional land use planning and environmental development.