Water Diversion Research Articles

Length-Weight-Age Relationship of Schizothorax eurystomus Kessler, 1872 and Comparison to Other Snow Trout Species in Central Asia

This study presents a comprehensive analysis of the length-weight relationship, condition factors, and age of Schizothorax eurystomus in the Shakhimardan River basin in Central Asia, along with a comparative perspective to other Schizothorax species in the region. The study found that S. eurystomus exhibits positive allometric growth, which is consistent with similar patterns observed in this species from the Syr Darya River basin. The two analyzed condition factors showed mean values within the normal range, indicating good feeding and environmental conditions. However, significant disparities between minimum and maximum values of these factors indicated varied growth conditions which may be influenced by anthropogenic factors. Age estimation using opercular bones showed variations in the total length among fish of the same age, and a clear age distribution pattern across different sites. Younger fish predominantly inhabited the shallower, warmer, and lower sections of the river, which is impacted by agricultural water diversion, while older specimens were found in areas with higher discharge and deeper pools. Overall, this research provides valuable insights into the life history traits of S. eurystomus, underlining the need for sustainable fishery management and conservation strategies in the Shakhimardan River basin. The findings also emphasize the importance of considering habitat quality and anthropogenic pressures regarding understanding both fish population dynamics and growth patterns.

Study on the Synergistic Effect of Primary Support and Surrounding Rock of Large Buried Depth Tunnel in Soft and Fractured Strata

The soft and fractured strata can cause significant deformation of surrounding rock during tunnel excavation. This study analyzes field monitoring test results and compares numerical simulations from the third bid project of the Dali I section construction within the water diversion project in central Yunnan to address the issue of significant deformation following tunnel excavation in soft and fractured strata. It proposes an optimized support scheme consisting of a densified steel arch and enhanced initial support strength and stiffness. In addition, the research investigates support effectiveness considering varying support strengths and steel arch ring spacing. The study findings indicated the following: (1) The tunnel traverses soft and fractured strata, causing unevenly distributed vertical convergence deformation around the cavern. The maximum settlement occurs at the crown, showing pronounced nonlinearity. (2) The maximum stress in the steel arch is concentrated at the arch crown, measuring −19.02 MPa. The arch remains compressed, with stress decreasing from the crown to the waist. (3) The axial force in the anchor bolt reduces from the crown to the arch’s waist on both sides. As the depth of the rock mass increases, the axial force in each anchor bolt decreases and the tension state is maintained. The maximum axial force reaches 46.57 kN. (4) The maximum displacement decreases from 4.21 to 0.15 cm after the optimized support structure is implemented, demonstrating the optimization scheme’s effectiveness. Future constructions can refer to this scheme and make necessary adjustments based on various terrain conditions to ensure safety.

Integrating SBAS-InSAR and Random Forest for Identifying and Controlling Land Subsidence and Uplift in a Multi-Layered Porous System of North China Plain

Controlling groundwater table decline could mitigate land subsidence and induced environmental hazards in over-explored areas. Nevertheless, this becomes a challenge in the multi-layered porous system as (in)elastic deformation simultaneously occurs due to vast spatiotemporal variability in the groundwater table. In this study, SBAS-InSAR was used to estimate annual land deformation during 2017–2022 in a specific region of North China Plain, in which aquifers are composed of many layers of fine-grained compressible sediments and the groundwater table has experienced a prolonged decline. The random forest (RF) was applied to establish the nonlinear relationship between accumulated deformation and its potential driving factors, including the depth to the groundwater table (GWD) and its change rate, and the compressible sediment thickness. Results show that the marked subsidence and uplift co-exist in the region even though the groundwater table has risen widely since the South–North Water Diversion Project. The land subsidence is attributed to inelastic compaction of the thick compressible deposits in depression cone centers, where the GWD is over 40 m and 90 m in the shallow and deep aquifers, respectively. In contrast, the marked uplift is primarily attributed to fast rising of the groundwater table (e.g., −2.44 m/a). The RF predictions suggest that, to control the subsidence, the GWD should be less than 20 and 70 m in the shallow and deep aquifers, respectively, and the rising rate of the GWD should increase to 2–5 times of current rates in the depression cones. To mitigate the marked uplift, the rising rate of the GWD should reduce to 1/2–1/5 of the current rates in the shallow aquifers. The uneven deformations of sediments in the depression cone centers and uplift in their boundaries may exacerbate geohazards. Therefore, it is vital to implement appropriate governance of groundwater recovery in the multi-layered porous system.

Design Method for Impeller of Centrifugal Pump With Guide Vanes Based on Oseen Vortex

Abstract Centrifugal pumps with guide vanes (GVs) are widely used in a pump as turbine, energy storage pump station, and water diversion project. The objective of this study is to establish a design method of centrifugal pumps for matching impeller outlet and diffuser inlet to reduce hydraulic loss. To this end, a theoretical prediction model based on the fluid governing equation and the Oseen vortex model is proposed to predict the velocity moment downstream the impeller of the centrifugal pump. Then, a design method is established to design the impeller of the centrifugal pump with guide vanes. A centrifugal pump with a specific speed of 127 is used to validate the theoretical prediction model, and results of velocity moment show that the deviation between predicted and simulated results is below 0.5% in average. Finally, the design method is applied, and results show that the average efficiency of redesigned pump under the working conditions is 1.04% higher than that of baseline pump, which validates the reliability of proposed design method by theoretical prediction based on Oseen vortex. Analysis on velocity distribution and turbulence eddy dissipation shows that the design method based on Oseen vortex can effectively improve the flow pattern and pump performance.

Water quality management of micro swamp wetland based on the “source-transfer-sink” theory: A case study of Momoge Swamp Wetland in Songnen Plain, China

Swamp wetlands play a pivotal role in conserving water sources, regulating river runoff, and maintaining water safety and balance. The study pioneers a new research framework in the field of pollution ecology of swamp wetlands, with a focus on the complex “source-transfer-sink” processes affecting water quality in micro swamp wetlands, an area previously under-researched. Taking the Momoge Wetland in the Songnen Plain as an example, we innovatively combined the “source-transfer-sink” theory with landscape patterns, topographic factors, and their impacts on wetland water quality. Using Partial Least Squares Structural Equation Modeling (PLS-SEM), our research quantifies and models the relationships among various environmental factors. This approach reveals how landscape patterns influence pollutant migration and water quality at a micro-scale. Our findings suggest that a 700-m buffer zone is most effective in capturing the fluctuations in water quality in arid wetlands, which is crucial for wetland management practices. We identified the main pollution sources in the Momoge Wetland, including sediment (21.60%), vegetation (24.94%), livestock and crop-related non-point sources (41.21%), and hydrodynamic factors such as water diversion (12.25%). In pollutant migration, land use emerged as the most significant factor affecting water quality (56.64%), followed by landscape patterns (25.54%). Notably, our study finds that grasslands are essential for water purification, and a uniform distribution of landscape patches significantly improves water quality. This research marks a significant stride in understanding and optimizing landscape patterns to enhance water quality in micro swamp wetlands. The insights gained are invaluable for the protection of these ecosystems and promoting their ecological value functions, providing a reference point for future wetland conservation and management strategies.

Does the South-to-North Water Diversion Project promote the growth of enterprises above designated size in the water-receiving areas?-Evidence from 31 provincial-level administrative regions in China.

The South-to-North Water Diversion Project (SNWDP) is believed to drive the next phase of sustainable productivity growth, meeting growing water demand, so as to address increasing environmental sustainability challenges. The Middle Route of SNWDP is regarded as an extremely large long-distance inter-basin water diversion project, which has benefited Henan, Hebei, Tianjin and Beijing since 2014 with great sustainable changes to the cities, groundwater, ecological environment, industrial structure and social development of the beneficiary areas. Taking the number of industrial enterprises above designated size (IEDS) in the water-receiving areas as the research object, this paper takes the year of policy implementation 2014 as the basic time point, evaluating the change of the number of IEDS in the beneficiary areas of the Middle Route of SNWDP through difference-in-difference model. The results show that: (1) The Middle Route of SNWDP promotes the additional growth of the number of IEDS in the beneficiary areas. (2) When the Middle Route of SNWDP promotes the growth of the number of IEDS in beneficiary areas, there is no regional difference for regions with different development levels. (3) The reasons why the Middle Route of SNWDP contributes to the additional growth of the number of IEDS are composed of promoting mixed ownership reform of enterprises in beneficiary areas, increasing water supply and increasing population. However, the Middle Route of SNWDP has not had a significant impact on the traditional total factor productivity or the components of production factors, technology and capital. From the final outcome, the South-to-North Water Diversion Project has played a facilitating role in the sustainable development of large-scale enterprises in the water-receiving areas.

Attention-ResNet-AR-LSTM: An intelligent method for PCCP deformation prediction via structure monitoring based on distributed fiber optics

The prestressed concrete cylinder pipeline (PCCP) is extensively employed in long water diversion projects due to its commendable performance and cost-effectiveness. Nonetheless, the continuous application of load on the prestressed steel wire during the production phase can amplify the creep deformation in both the concrete and steel cylinder of the PCCP. This phenomenon may potentially lead to the development of cracks at the socket end of the PCCP, posing a significant risk to the safe operational integrity of the pipeline. In this study, the strain development prediction model of PCCP concrete and steel cylinder is constructed through the integration of ResNet, AR, and LSTM modules, and the attention mechanism is also applied. Based on the prototype test of PCCP structure monitoring, the strain values of steel cylinder and inner concrete were recorded by pre-set distributed fiber optic sensors on the 1st, 3rd, 5th, 7th, 9th, 11th, 13th, 15th, 17th, and 20th day after the production of PCCP. Then an Attention-ResNet-AR-LSTM model is constructed to predict the strain development of PCCP steel cylinder and concrete based on monitoring data on the 20th day using the data of 1st to 11th days. For steel cylinder and concrete structures, the R2 of the proposed models is above 98%, indicating that the proposed models can capture the strain changes of different structures well. Compared with other deep models and machine learning models, the proposed model also shows a significant predictive ability. This model introduces a novel approach to forecast strain evolution during the manufacturing of PCCP.

Estimating Water Use Efficiency for Major Crops in Chihuahua, Mexico: Crop Yield Function Models vs. Evapotranspiration

Water use in agriculture is a critical aspect of sustainable food production. Efficient water management is essential to address both yield optimization and environmental concerns. The current study evaluated the water diversions by the Irrigation District 05—Delicias (DR-05), in the State of Chihuahua, Mexico, for four major crops grown in the region including alfalfa, chile, pecans and peanuts. The amounts of water applied to raise these crops were compared to the amounts of water use estimated with the evapotranspiration (ET) method and with the crop yield function model, and respective water use efficiencies were estimated with both the methods. The water use efficiency measured using the ET estimation (WUE-ET) for alfalfa ranged from 60.9% to 70.4%, while the water use efficiency derived from the yield function data (WUE-YF) showed lower values and ranged from 43.6% to 59.7%. In the case of chile, the opposite trends were observed than in alfalfa, with the WUE-ET for chile ranging from 47.7% to 54.8%, and WUE-YF showing higher values that ranged from 49% to 70%. In the case of peanuts and pecans, only the WUE-ET was estimated and it ranged from 55.9% to 68.8% for peanuts and 90.9% to 116.9% pecans, respectively. Among the four crops studied, pecans were found to have the highest WUE-ET, with values of WUE-ET reaching higher than 100%. However, it is to be noted that these high values of water use efficiencies are more indicative that pecans are probably under irrigated.

Coupling coordination relationship of water resources, eco-environment and socio-economy in the water-receiving area of the Lower Yellow River

Fully understanding the interrelationship and the coordinated development level of water resources (WR), eco-environment (EE) and socio-economy (SE) is an essential precondition for regional sustainable development. We constructed a complex analytical framework consisting of WR, EE and SE subsystems in the water-receiving area of the Lower Yellow River, and quantitatively investigated the coupling coordination relationship among them. An improved obstacle degree model was developed to analyze the level and the major obstacles of coordinated development from 2001 to 2020, together with the coupling coordination degree model. A prediction model combined by the autoregressive integrated moving average model, the gray model and the artificial neural network model was built to explore the development trend from 2021 to 2025. It was found that (1) the coordinated development level showed a continuous growth from reluctant coordination in 2001–2002 to high coordination in 2015–2020. Spatially, Shandong province was slightly more coordinated than that of Henan province on the whole. (2) With sustained rapid SE development and growing pressure on water supply and environmental capacity, the major obstacles for coordinated development changed from SE factors to WR and EE factors before and after 2010. (3) The coordinated development level will continue to increase in 2021–2025, especially in the “promote WR and EE protection” scenario. In the future, water scarcity will become the key problems for coordinated development. Taking account of the available water diversion from the Yellow River, local government should put more effort into water use efficiency improvement. These results offer an important reference for decision-making and management of regional sustainable development.

Joint optimal operation of the South-to-North Water Diversion Project considering the evenness of water deficit

Abstract. Inter-basin water transfer projects are the main measure to address the water deficit crisis caused by uneven distribution of water resources. The current water transfer operation mainly tends to be present in areas with small water transfer costs and is prone to encounter the problem of spatial and temporal imbalances in water allocation. To address these issues, this paper defines a water deficit evenness index (WDEI), aimed at minimizing regional differences in water scarcity and sharing the pressure of water scarcity as a social demand objective. This index is incorporated into a joint optimization model for the Jiangsu section of the South-to-North Water Diversion Project (J-SNWDP), which comprises both the ecological objective of the total water deficit (TWD) and the economic objective of the pumping water (PW). Further, the Nondominated Sorting Genetic Algorithm III (NSGA-III) and multi-attribute decision-making were applied to solve the model and obtain an optimal operation strategy. The results showed the following: (1) the WDEI defined in this paper can mitigate the synchronized water scarcity in certain water users. In typical normal years (wet year and dry year), the WDEI shows a reduction of 94.2 % (81.8 %, 76.7 %) compared to the historical operation strategy. (2) The optimized operation strategy can significantly reduce TWD and PW by 82.06% (37.69 %, 52.36 %) and 45.13 % (3.25 %, 21.51 %) compared with the historical values, respectively, which can improve the water supply satisfaction and reduce the project cost. At the same time, the lake storage capacity of the optimal operation strategy performs well, and the water transfer efficiency of the river is significantly improved. (3) In this paper, targeted optimal operation strategies and potential ways to secure the project tasks are proposed for different natural flow. Overall, it is of great significance to study the water supply equity in the J-SNWDP to alleviate the concentrated water deficit in Jiangsu Province and other similar regions.

Assessing entrainment of larval fish in the Hogback Diversion Canal, San Juan River

AbstractWater diversions worldwide may entrain or impinge fish and have population‐level impacts, but barriers like fish screens can reduce such threats. Traditional barriers are ineffective in the San Juan River, USA, due to high sediment and debris loads, so the Hogback Diversion Canal, NM, employs a novel weir wall design to reduce entrainment of sub‐adult and adult fishes. We evaluated the effectiveness of the weir wall in reducing the entrainment of larval fish using a combination of experimental and overnight trials. Larval fish densities were compared between the irrigation canal that delivers water to irrigators and subsequently entrains fish and the bypass canal that conveys water and fish back to the river. The density of hatchery‐produced larval fish collected in the irrigation canal during the experimental trial (0.74 fish/m3) was 52% of their density in the bypass canal (1.43 fish/m3), suggesting entrainment reduction. The density of wild‐produced larvae during overnight trials indicated some minor, mostly nonsignificant, differences between catch rates in irrigation and bypass canals, ontogenetic phases, and sampling dates. Though entrainment rates of wild‐produced larvae were not significantly reduced, density differences among postflexion mesolarvae and metalarvae suggest possible entrainment reduction of more developed ontogenetic phases. More intensive research is necessary to better elucidate the efficacy of the novel weir wall for reducing the entrainment of larval fish. However, our larval fish results and the results from prior large‐bodied entrainment studies suggest the novel weir wall may reduce fish entrainment in water diversions and benefit fluvial ecosystems in which traditional screens are unfeasible.

Simulation of the Entire Process of an Interbasin Water Transfer Project for Flow Routing

The flow routing process plays a crucial role in underpinning the execution of real-time operations within interbasin water transfer projects (IWTPs). However, the water transfer process within the supplying area is significantly affected by the time lag of water flow over extended distances, which results in a misalignment with the water demand process in the receiving area. Hence, there is an imperative need to investigate the flow routing patterns in long-distance water transfer processes. While MIKE11(2014 version) software and the Muskingum method are proficient in simulating flow routing within a water transfer network, they fall short in addressing issues arising from mixed free-surface-pressure flows in water transfer pipelines. This study enhanced the capabilities of the MIKE11(2014 version) software and the Muskingum method by introducing the Preissmann virtual narrow gap method to tackle the challenge of simulating mixed free-surface-pressure flows, a task unattainable by the model independently. This approach provides a clear elucidation of hydraulic characteristics within the water transfer network, encompassing flow rates and routing times. Furthermore, this is integrated with the Muskingum inverse method to compute the actual water demand process within the supplying area. This methodology is implemented in the context of the Han River to Wei River Diversion Project (HTWDP). The research findings reveal that the routing time for the Qinling water conveyance tunnel, under maximum design flow rate conditions, is 12.78 h, while for the south and north main lines, it stands at 15.85 and 20.15 h, respectively. These results underscore the significance of the time lag effect in long-distance water conveyance. It is noteworthy that the average errors between simulated and calculated values for the south and north main lines in the flow routing process are 0.45 m3/s and 0.51 m3/s, respectively. Compared to not using the Preissmann virtual narrow gap method, these errors are reduced by 59.82% and 70.35%, indicating a significant decrease in the discrepancy between simulated and calculated values through the adoption of the Preissmann virtual narrow gap method. This substantially improves the model’s fitting accuracy. Furthermore, the KGE indices for the flow routing model are all above 0.5, and the overall trend of the reverse flow routing process closely aligns with the simulated process. The relative errors for most time periods are constrained within a 5% range, demonstrating the reasonability and precision of the model.

A holistic approach to projecting streamflow and analyzing changes in ecologically relevant hydrological indicators under climate and land use/cover change

Understanding streamflow change and its ecological impacts under climate change and land use/cover change (LUCC) makes possible the improvement of water and ecological governance decision-making. Gaining a comprehensive understanding of the drivers of historical streamflow changes can provide valuable insights for effective projections of future streamflow. Meanwhile, future changes in ecologically relevant hydrological indicators need more attention to maintain the ecological stability of rivers. This study has developed a holistic framework based on a physically based model (the Variable Infiltration Capacity model, or VIC) and the indicators of hydrological alteration (IHA) method to decouple the drivers of historical streamflow change and to project changes in future streamflow and ecologically relevant hydrologic indicators. The proposed framework was applied in the upper Han River basin (UHRB), which is the water source for the water diversion project in China. The results showed that climate change contributed 99.67 % of the streamflow decrease in the 1980–1990s and 108.21 % and 102.09 % of the streamflow increase in the 1990–2000s and 2000–2010s respectively. LUCC had a weak impact on streamflow in these three periods. Projected climate change will further exacerbate streamflow change. The projected monthly streamflow is expected to increase from October to December. The counts of streamflow pulses are expected to decrease, but the duration of each high pulse will increase. These changes will cause stress in floodplain vegetation, alterations to stream chemistry, reductions in fish diversity (decreased streamflow pulses), and alterations to river landscape and animal habitat (increased flood duration). The developed framework is expected to provide significant technical guidance for water resource management and river conservation.

Land subsidence in Beijing: response to the joint influence of the South-to-North Water Diversion Project and ecological water replenishment, observed by satellite radar interferometry

ABSTRACT The South-to-North Water Diversion Project Middle Route (SNWD-MR) annually diverts hundreds of millions of cubic meters of water from the Danjiangkou Reservoir to Beijing, significantly impacting the regional groundwater cycle. To conserve water resources, the government has implemented ecological water replenishment (EWR) in some water systems. This study aimed to study the coupled process of groundwater dynamics and land subsidence (LS) in Yongding River (YDR) basin (Beijing section) following the implementation of the SNWD-MR and EWR. First, an Interferometric Synthetic Aperture Radar (InSAR) time series technique was used to detect spatial and temporal distributions of surface displacement between 2015 and 2020 based on satellite images from Sentinel-1A/B. The results indicated a predominant LS deceleration trend during the InSAR observation period. The area with subsidence velocity below 20 mm/yr decreased significantly by 18.6% after SNWD-MR and EWR (from 2016 to 2020). Then, groundwater level fluctuations during the InSAR observation period were analyzed using groundwater measurement well data. Over 60% of these wells showed a rebound in groundwater levels after the implementation of SNWD-MR and EWR. The polynomial distribution lag model (PDL) revealed the association between LS and groundwater level changes, depicting both short- and long-term lag effect. The results showed significant spatial and temporal heterogeneity on the short- and long-term response between groundwater level change and regional subsidence. In addition, we calculated the differential subsidence slope based on the InSAR-derived LS and analyzed its impact on the river slope after SNWD-MR and EWR. The results show that two sections with significant severe differential subsidence slope occur between 0 and 14,000 m and between 54,000 and 78,000 m along the YDR. The slope change caused by LS may reduce the conveyance capacity of surface canals, and more attention should be paid in those two sections. These findings have an important scientific significance for management strategy for LS control against the background of SNWD-MR and EWR.

A novel framework for integrative assessment of water balance health in China

Existing studies on water resource issues focus on water scarcity while largely lacking an integrative water balance health assessment and ignoring the combined impacts of water quality, water transfer, and unconventional water resources on water balance. Here, we proposed a novel framework for assessing regional water balance health considering three dimensions of water problems about imbalances: water scarcity, water inequality, and systems incoordination. This paper first quantified the levels of water balance health at multiple geographic and temporal scales in China, and then investigated the critical components and the impacts of improved surface water quality, inter-basin water transfer, and unconventional water use on the local water balance health. Results showed that China was under an unhealthy water balance due to multiple imbalances based on the annual average assessments during 2014–2018. More than 45% of the national population (∼615 million people) was affected by an unhealthy water balance. Hotspots with unhealthy water balance exhibited spatial heterogeneity and temporal variability, with Northern China experiencing unhealthy water balance throughout the year, while Southern China usually faced this issue during the winter. Unhealthy water balance in Northern China was primarily driven by water scarcity, while in the west of the Hu-Huanyong Line, water inequality exacerbated the situation. Southeastern China faced systems incoordination, particularly vulnerable during extreme events, such as severe droughts. More than 400 and 150 million people benefited significantly from improved surface water quality and inter-basin water transfer, respectively, relieving unhealthy water balance. However, the effectiveness of unconventional water use was found to be limited. This study contributed to a better understanding of water balance health and facilitated the development of policies for integrated water resources management in China.

The variation of DOM during long distance water transport by the China South to North Water Diversion Scheme and impact on drinking water treatment

The variation of DOM during long distance water transport by the China South to North Water Diversion Scheme and impact on drinking water treatment

Assessing the impact of incentive coordination effect on the equilibrium of agricultural water usage by China's South-to-North Water Diversion Middle Route Project.

In recent years, the sustainable development of agricultural water resources has received much attention. The mismatch between agricultural water distribution patterns, land resources, and socioeconomics threatens food production, especially in vast water-scarce plains. Therefore, monitoring agricultural water spatial equilibrium (AWRSE) is necessary. Based on equilibrium theory and information entropy, in this study, the AWRSE evaluation model is constructed from three aspects: agricultural water resources, land resources, and socioeconomics. In addition, the relationship between social factors with cropping pattern as the primary explanatory variable and AWRSE was examined in conjunction with the extended STIRPAT model and applied to the water-receiving area of the Middle Route of South-to-North Water Diversion Project (MR-SNWDP). The results show that compared with the pre-diversion period, the AWRSE of 75% of the water-receiving cities has been significantly improved by the MR-SNWTP water supply. The MK test z value of the overall regional AWRSE has changed from - 0.328 to - 2.65, and the AWRSE development has shifted from not significantly better to significantly better. The cropping pattern shows a positive response to this development, and this effect can be mitigated in the late stage of water transfer; when the proportion of food crop cultivation increases by 1%, the sub-regional AWRSE value will increase by 0.347%. The evaluation model demonstrates a broad range of inclusiveness and application potential; it provides novel insights for examining agroecological, social, and economic stability.

Research on the prediction of mine water inrush disasters based on multi-factor spatial game reconstruction

Water damage in mines poses a widespread challenge in the coal mining industry. Gaining a comprehensive understanding of the multi-factor spatial catastrophe evolution mechanism and process of floor water inrush is crucial, which will enable the achievement of dynamic, quantitative, and precise early warning systems. It holds significant theoretical guidance for implementing effective water prevention and control measures in coal mines. This study focuses on the issue of water inrush in the coal seam floor, specifically in the context of Pengzhuang coal mine. By utilizing a small sample of non-linear characteristics derived from drilling geological data, we adopt a multifactor spatial perspective that considers geological structure and hydrogeological conditions. In light of this, we propose a quantitative risk prediction model that integrates the coupled theoretical analysis, statistical analysis, and machine learning simulation methods. Firstly, the utilization of a quantification approach employing a triangular fuzzy number allows for the representation of a comparative matrix based on empirical values. Simultaneously, the networked risk transmission effect of underlying control risk factors is taken into consideration. The application of principal component analysis optimizes the entropy weight method, effectively reducing the interference caused by multifactor correlation. By employing game theory, the subjective and objective weight proportions of the control factors are reasonably allocated, thereby establishing a vulnerability index model based on a comprehensive weighting of subjective and objective factors. Secondly, the WOA-RF-GIS approach is employed to comprehensively explore the interconnectedness of water diversion channel data. Collaborative Kriging interpolation is utilized to enhance the dimensionality of the data and facilitate spatial information processing. Lastly, the representation of risk is coupled with necessary and sufficient condition layers, enabling the qualitative visualization of quantitative results. This approach aims to accurately predict disaster risk with limited sample data, ultimately achieving the goal of precise risk assessment. The research findings demonstrate that the reconstructed optimization model based on multi-factor spatial game theory exhibits high precision and generalization capability. This model effectively unveils the non-linear dynamic processes associated with floor water inrush, which are influenced by multiple factors, characterized by limited data volume, and governed by complex formation mechanisms. The identification of high-risk areas for water inrush is achieved with remarkable accuracy, providing invaluable technical support for the formulation of targeted water prevention and control measures, ultimately ensuring the safety of coal mining operations.

Propagation characteristics of meteorological drought to hydrological drought considering nonlinear correlations - A case study of the Hanjiang River Basin, China

Meteorological drought serves as the precursor to hydrological drought. Clarifying the propagation characteristics from meteorological drought to hydrological drought is crucial for predicting and mitigating this severe natural disaster. In this study, we proposed an assessment framework that integrates both linear and nonlinear methods to characterize the transition from meteorological to hydrological drought in terms of drought response time, effective drought transformation rate, and drought propagation threshold. Utilizing ERA5 land reanalysis data (1951–2022) and focusing on the Hanjiang River Basin in China, we analyzed drought propagation features with and without inter-basin water diversion. Extracted drought event pairs indicate that a more significant meteorological drought does not necessarily result in a more severe hydrological drought, and vice versa, which confirms the nonlinear propagation from meteorological to hydrological drought. The drought response times derived using the linear method are, on average, two months shorter than those derived using the nonlinear method. Inter-basin water diversion will weaken the drought linear correlation while strengthening the nonlinear correlation. When the annual water diversion exceeds 12.0 billion m3, the drought response time will experience a sudden reduction. This research provides a scientific method and reference for basin-scale water resource management and drought mitigation practice.

Water Conservation Implications Based on Tempo-Spatial Characteristics of Water Footprint in the Water-Receiving Areas of the South-to-North Water Diversion Project, China

In order to continuously promote water conservation efforts to alleviate the pressure of water diversion, water footprint (WF) is used as an effective tool to measure water utilization in the water-receiving areas of the Middle Route and Eastern Route of the South-to-North Water Diversion Project (SNWDP). The tempo-spatial variations of WF and spatial equilibrium of water footprint intensity (WFI) in the study area are quantified using the Mann–Kandle trend test, Sen’s slope, and Dagum Gini coefficient decomposition method for the years of 2005–2020. The results show that WF has a significant decreasing trend (Sen’s slop < 0, significant level < 0.05) in 17 cities in the study area, whereas WF shows a significant increasing trend (Sen’s slop > 0, significant level < 0.05) in 10 cities. Cities in the water-receiving areas are categorized into three types based on the contribution of the water utilization sector to changes in WF as follows: agriculture water-dominated city (AD), domestic and ecological water-dominated city (DED), and virtual water trade-dominated city (VWTD). Accordingly, targeted water conservation recommendations are made for these three kinds of cities, and it is suggested that AD, DED, and VWTD cities need to focus on advanced irrigation technologies, water reuse, and trade restructuring, respectively. The overall Gini coefficient of WFI fluctuates between 0.219 and 0.267 in the water-receiving areas of the Middle Route, which is dominated by the differences in city level. However, it fluctuates between 0.412 and 0.278 in the water-receiving areas of the Eastern Route, which is dominated by the differences in provincial level. Accordingly, water conservation hotspots are determined at the city level in the Middle Route and at the provincial level in the Eastern Route with different water management policies. These results provide a scientific support for water conservation management in the water-receiving areas of the SNWDP, as well as a methodological reference for the tempo-spatial characteristics of WF and their implications for water conservation.