Search Results (91)

The hydrodynamics characteristics of artificial water diversion canals with long-distance and inter-basin multi-stage sluice gate regulations are prone to sudden increases and decreases, and sluice gate discharge differs from that of natural rivers. Research on the change characteristics of hydrological elements in artificial canals under the control of sluice gates is lacking, as are scientifically accurate calculations of sluice gate discharge. Therefore, addressing these gaps in long-distance artificial water transfer is of great importance. In this study, real-time operation data of 61 sluice gates, pertaining to the period from May 2019 to July 2021, including data on water levels, flow discharge, velocity, and sluice gate openings in the main canal of the Middle Route of the South-to-North Water Diversion Project of China, were analyzed. The discharge coefficient of each sluice gate was calculated by the dimensional analysis method, and the unit-width discharge was modeled as a function of gate opening ($e$), gravity acceleration ($g$), and energy difference ($H$). Through logarithmic transformation of the Buckingham Pi theorem-derived equation, a linear regression model was used. Data within the relative opening orifice flow regime were selected for fitting, yielding the discharge coefficients and stage–discharge relationships. The results demonstrate that during the study period, the water level, discharge, and velocity of the main canal showed an increasing trend year by year. The dimensional analysis results indicate that the stage–discharge response relationship followed a power function ($Q\propto {(\frac{H}{e})}^{constant}$) and that there was a good linear relationship between $l{g}^{(\frac{H}{e})}$ and $l{g}^{(\frac{K}{e})}$ (R² > 0.95, $K={(q^2/g)}^{1/3}$). By integrating geometric, operational, and hydraulic parameters, the proposed method provides a practical tool and a scientific reference for analyzing sluice gates’ regulation and hydrological response characteristics, optimizing water allocation, enhancing ecological management, and improving operational safety in long-distance inter-basin water diversion projects. Full article

This study takes the Danjiangkou reservoir basin, which is the water source area of the South-to-North Water Diversion Project, one of the largest water diversion projects in the world, as the research area. Three different types of evapotranspiration (ET) datasets are adopted, including the Global Land Evaporation Amsterdam Model (GLEAM), European Centre for Medium-Range Weather Forecasts ERA5—Land Component (ERA5Land), and Complementary Relationship (CR) datasets. These datasets are analyzed for spatiotemporal evolution and data fusion using Mann–Kendall analysis, Sen’s Slope analysis, and Extended Triple Collocation (ETC). The aim is to improve the accuracy of evapotranspiration estimation in the watershed of the water source area. The results show the following: (1) All three sets of evapotranspiration data indicate an increasing trend in the watershed, with rates of 0.78 mm/year, 0.14 mm/year, and 2.56 mm/year, respectively. Additionally, the seasonal variation in evapotranspiration is significant, with the rate of change being summer > spring > autumn > winter. (2) The data fusion results indicate that ERA5Land performs best in the water source area watershed, with the smallest root mean square error (RMSE) value. In the fused data, ERA5Land’s evapotranspiration data account for the largest proportion at 59.93%, GLEAM ET data account for 39.96%, and CR’s evapotranspiration data account for the smallest proportion at only 0.11%. (3) The spatial distribution shows that the fused data fully exploits the advantages of different evapotranspiration data, inherits the advantages of ERA5Land and GLEAM ET products, and achieves effective fusion of multi-source data, thereby forming a more accurate dataset. These research findings provide scientific references for the construction of digital twin watersheds, intelligent water resource allocation, and effective responses to climate change in the water source area of the South-to-North Water Diversion Project. Full article

To address the water-use conflicts between the original water-receiving areas of the lower Hongze, Luoma, and Nansihu lakes and the receiving areas of the East Route of the South-to-North Water Diversion (ESNWD) project, a multi-objective simulation-optimization coupling model was developed. To ensure that the operating costs of the system are reduced while safeguarding water in the original receiving area of the lakes, the model had two objectives: minimizing the water shortage in the original receiving areas of the lakes and minimizing the total system cost of the ESNWD project. The water allocation scheme was optimized by adjusting the northward water transfer levels of the lakes. The Nondominated Sorting Genetic Algorithm II was used to solve the model and generate a set of non-inferior solutions for the northward water transfer levels of the lakes. The optimal solution for the northward water transfer level in the ESNWD project was obtained using the entropy weight technique for order preference by similarity to an ideal solution method. The results showed that, compared with the current northward water transfer levels, the optimally obtained northward water transfer level solution could reduce the water shortage in the original receiving area by 7.86% at a cost increase of 0.45%, which balanced the water demand of the original lake receiving area with the economic requirements of the water-receiving area of the ESNWD system, respectively. Thus, the proposed solution effectively improves the system benefits. Full article

The riverine fish species are highly vulnerable and responsive to large-scale water diversion projects. These adverse impacts are more pronounced in the plateau river ecosystems, which may change the environmental conditions of fish habitats and community structure. We investigated the effects of various environmental factors on fish diversity in seven rivers of the Western Sichuan Plateau, which is the planned area of China’s South-to-North Water Diversion Project. Twenty-two fish species, including eight exotic species, were collected during September 2023 (Autumn) and May 2024 (Spring). The fish communities exhibited no significant difference between seasons but had prominent variations among different rivers. The heterogeneity of fish communities was significantly and positively correlated with the geographical distance between the sampling sites (based on a projected coordinate system). Furthermore, the canonical correspondence analysis (CCA) illustrated that altitude contributed more to the distribution of fish species than other physicochemical factors, such as channel width, conductivity, and water temperature. Rivers at low altitudes are likely to be vulnerable to invasion of exotic fish. Our results demonstrated that the dispersal limitation by geographical distance and altitudinal gradient were the primary regulatory factors on the spatial differentiation of fish communities in the rivers of the study area, which reflected a high dependence of fish species on local habitats. As the water diversion project is implemented, more attention is expected to be paid to protecting fish habitats and regime shifts in fish communities. Additionally, the risk assessment of biological invasion under inter-basin water transfers and human activities should be carried out as soon as possible. Full article

Determining the relative roles of climatic versus anthropogenic factors in runoff alterations is important for sustainable water resource utilization and basin management. The Danjiang River watershed is a crucial water resource area of the middle route of the South-to-North Water Transfer Project. In this study, four widely used quantitative methods, including the simple linear regression, the double mass curve, the paired year with similar climate conditions, and an elasticity method based on the Budyko framework were applied to detect the relative contribution of climatic and anthropogenic factors to runoff variation in the Danjiang River watershed. The calculation processes of each method were systematically explained, and their characteristics and applications were summarized. The results showed that runoff decreased significantly (p < 0.05) with an average change rate of −3.88 mm year⁻¹ during the period of 1960–2017, and a significant change year was detected in 1989 (p < 0.05). Generally, consistent estimates could be derived from different methods that human activity was the dominant driving force of significant runoff reduction. Although the impacts of human activity estimated by the paired year with similar climate conditions method varied among paired years, the other three methods demonstrated that human activity accounted for 80.22–92.88% (mean 86.33%) of the total reduction in the annual runoff, whereas climate change only contributed 7.12–19.78% (mean 13.67%). The results of this study provide a good reference for estimating the effects of climate change and human activities on runoff variation via different methods. Full article

The South-to-North Water Diversion Project in China is the world’s largest water transfer project, aiming to address water shortages in northern China by channeling water from the water-rich southern regions. Water resources in Tianjin have long been in severe deficit, with excessive groundwater extraction causing significant surface subsidence, negatively impacting urban infrastructure and economic development. As a result, Tianjin has become a key beneficiary of this water diversion project. To investigate the current situation of surface subsidence, we obtained the vertical displacement time series from 21 GNSS stations across Tianjin from 2011 to 2021 and analyzed overall subsidence changes and rehabilitation status. Results indicate that no clear surface subsidence was observed in the northern regions of Tianjin due to groundwater extraction mainly in unconfined aquifers. The southwestern region experienced the most significant surface subsidence due to overexploitation of deep groundwater, with peak cumulative subsidence exceeding 600 mm during the study period. The central, eastern, and southeastern coastal regions also faced severe surface subsidence with cumulative amounts ranging from 100 mm to 400 mm. The alleviation of subsidence predominantly benefits from continuous water supply from the South to North Water Diversion Project, which resulted in most stations significantly slowing down or even stabilizing their settlement rates after 2018. Therefore, the South-to-North Water Diversion Project plays a crucial role in addressing the persistent water resource shortage and mitigating long-term surface subsidence in Tianjin by ensuring a continuous water supply and significantly reducing the need for groundwater extraction. Our findings indicate positive measures, such as water diversion projects and water management policies, can serve as valuable references for other regions around the world facing similar water scarcity and groundwater overexploitation. Full article

The South-to-North Water Diversion Project in China is an extensive inter-basin water transfer project, for which ensuring the safe operation and maintenance of infrastructure poses a fundamental challenge. In this context, structural health monitoring is crucial for the safe and efficient operation of hydraulic infrastructure. Currently, most health monitoring systems for hydraulic infrastructure rely on commercial software or algorithms that only run on desktop computers. This study developed for the first time a lightweight convolutional neural network (CNN) model specifically for early detection of structural damage in water supply canals and deployed it as a tiny machine learning (TinyML) application on a low-power microcontroller unit (MCU). The model uses damage images of the supply canals that we collected as input and the damage types as output. With data augmentation techniques to enhance the training dataset, the deployed model is only 7.57 KB in size and demonstrates an accuracy of 94.17 ± 1.67% and a precision of 94.47 ± 1.46%, outperforming other commonly used CNN models in terms of performance and energy efficiency. Moreover, each inference consumes only 5610.18 $\mathsf{\mu }$J of energy, allowing a standard 225 mAh button cell to run continuously for nearly 11 years and perform approximately 4,945,055 inferences. This research not only confirms the feasibility of deploying real-time supply canal surface condition monitoring on low-power, resource-constrained devices but also provides practical technical solutions for improving infrastructure security. Full article

The Danjiangkou Reservoir is the water source of the middle route of China’s South-to-North Water Diversion Project, encompassing the Dan Reservoir and Han Reservoir. However, little is known about the ecological functions of this important ecosystem. Based on a survey conducted in 2023 in the Dan Reservoir, a mass balance model was constructed using Ecopath with Ecosim 6.6 software to characterize its food web structure and ecosystem properties. The model consisted of 18 functional groups, including producers, consumers, and detritus, covering the entire process of energy flow in the ecosystem. The outputs indicated that the fractional trophic level of functional groups in the Dan Reservoir ecosystem ranged from 1.00 to 3.50. The ecotrophic efficiencies of the main economic fish species were all less than 0.9, and the ecotrophic efficiencies of phytoplankton and detritus were less than 0.5. There were two main food chains: the detritus food chain (39%) and the grazing food chain (61%). The total energy transfer efficiency between trophic levels was only 6.02%, and there was a significant phenomenon of energy transfer blockage between trophic levels II and V. Analysis of the overall characteristics of the ecosystem revealed that the total primary production to total biomass (67.96619), connectance index (0.274), and Finn’s cycling index (2.856) of the Dan Reservoir ecosystem all indicate that the ecosystem is immature, with low nutrient recycling efficiency and poor resistance to external disturbances. This may be related to the low proportion of silver carp and bighead carp in the reservoir and the unreasonable structure of the fish community. Our results suggest that it is necessary to scientifically adjust the structure of the fish community, enhance the proportion of filter-feeding and omnivorous fish to improve the energy flow efficiency, and promote the maturity and stability of the Dan Reservoir. Full article

With a huge capital and labor input influx, inter-basin water transfer (IBWT) projects have been shown to effectively mitigate water stress and ensure the water demand for social and economic development in the receiving area. Whether they have promoted the improvement of regional water use efficiency (WUE) is crucial for sustainable management of regional water resources. Targeting the South-to-North Water Transfer Project (SNWTP), the largest and most ambitious inter-basin water transfer project in China, this study establishes quantitatively econometric models to analyze the impact of different water diversion projects, specifically the eastern route of the SNWTP (ER-SNWTP), middle route of the SNWTP (MR-SNWTP), and diversion from the main stream of the Yellow River (DYR), on the regional water consumption per unit of GDP; regional water stress, water use structure, economic structure, and urbanization level are used as control variables in different types of cities in the Yellow River Basin, and some intriguing results are found. While the overall water transfer project demonstrates a positive impact on water use efficiency, the effects of the three water transfer measures vary significantly. The ER-SNWTP does not exhibit a notable positive effect on regional water use efficiency, whereas the MR-SNWTP demonstrates a significant positive impact. Interestingly, the DYR has a notable negative influence on water use efficiency in developed cities. The water use structure, shaped by the pricing, scale, and policies of different projects, emerges as a pivotal factor in explaining these differences. Finally, this paper suggests that the impact of water transfer projects on the improvement of regional water use efficiency be viewed from a more comprehensive and developmental perspective. Full article

Beijing, China’s capital city, has experienced decades of severe land subsidence due to the long-term overexploitation of groundwater. The implementation of the South-to-North Water Diversion Project (SNWDP) and artificial ecological restoration have significantly changed Beijing’s hydro-ecological and geological environment in recent years, leading to a widespread rise in groundwater levels. However, whether the related land subsidence has slowed down or reversed under these measures has not yet been effectively monitored and quantitatively analyzed in terms of time and space. Accordingly, in this study, we proposed using an improved time-series deformation method, which combines persistent scatterers and distributed scatterers, to process Sentinel-1 images from 2015 to 2022 in the Beijing Plain region. We performed a geospatial analysis to gain a better understanding of how the new hydrological conditions changed the pattern of deformation on the Beijing Plain. The results indicated that our combined PS and DS method provided more measurements both in total quantity and spatial density than conventional PSI methods. The land subsidence in the Beijing Plain area has been effectively alleviated from a subsidence region of approximately 1377 km² in 2015 to only approximately 78 km² in 2022. Ecological restoration areas in the northeastern part of the Plain have even rebounded over this period, at a maximum of approximately 40 mm in 2022. The overall pattern of ground deformation (subsidence and uplift) is negatively correlated with changes in the groundwater table (decline and rise). Local deformation is controlled by the thickness of the compressible layer and an active fault. The year 2015, when anthropogenic water transfers were eliminated and ecological measures to recharge groundwater were implemented, was the crucial turning point of the change in the deformation trend in the subsidence history of Beijing. Our findings carry significance, not only for China, but also for other areas where large-scale groundwater extractions are causing severe ground subsidence or rebound. Full article

In order to realize the goal of ice-free water conveyance in the winter for water conveyance projects in cold regions, the operation principle of ice-free water conveyance through channels is described based on the two ice-melting measures of a solar heating gallery and heated storage tank. Based on the multi-year meteorological data and the theory of a product probability event, the concept of a “comprehensive satisfaction rate” was proposed, and then the joint optimal regulating model under two ice-melting measures was established, and the genetic algorithm was used to solve the problem, which solved the important limitations of the economic and efficiency optimization of different ice-melting measures. This paper applies this model to the Zhanghe control gate–Mangniuhe control gate section of the middle route of the South-to-North Water Transfer Project. According to the optimization analysis of a large number of operating conditions, the operating costs of the ice-melting measures have also increased with the increase in the comprehensive satisfy rate. In the operation process, the water temperature along the lines presents a “ladder-like” shape. The average hourly flow and average hourly water temperature of the heated water storage tank have the characteristics of overall unity and local complementarity. With the increase in the water flow and downstream depth before the gate, its operating cost also increases. The increase in the flow velocity at the same time can increase the heat transfer efficiency, reducing the operating costs. In addition, the water temperature of the channel with a solar heating gallery decreased more slowly than that without a solar heating gallery due to its good thermal insulation effect. Full article

North China (NC) is experiencing significant groundwater depletion. We used GRACE and GRACE-FO RL06 Level-2 data with Mascon data from April 2002 to July 2022. We fused these two types of data through the generalized three-cornered hat method and further combined them with hydrological models, precipitation, in situ groundwater-level, and groundwater extraction (GWE) data to determine and verify temporal and spatial variations in groundwater storage (GWS) in NC. We quantitatively assessed groundwater sustainability by constructing a groundwater index in NC. We further explored the dynamic cyclic process of groundwater change and quantified the impact of the South-to-North Water Transfer Project (SNWTP) on GWS change in NC. The overall GWS shows a decreasing trend. The GRACE/GRACE-FO-derived GWS change results are consistent with those shown by the in situ groundwater-level data from the monitoring well. Groundwater in NC is in various states of unsustainability throughout the period 2002 to 2022. The SNWTP affected the water use structure to some extent in NC. This study elucidates the latest spatial–temporal variations in GWS, especially in the groundwater sustainability assessment and quantitative description of the effects of the SNWTP on changes in GWS in NC. The results may provide a reference for groundwater resource management. Full article

China’s South–North Water Transfer Project has been questioned as it has resulted in significantly negative issues. Drawing on the notion of hydrosocial territories, this article examines the contested hydraulic configuration and counter-imaginaries from local water users’ perspectives and their specific adaptation strategies in the South–North Water Transfer Project. This article argues that local water users in a Chinese context can only adopt adaptation strategies that are determined by their socio-economic backgrounds. This has led to significant social and environmental injustice. Addressing these issues is crucial for tackling inequities in the South–North Water Transfer Project and achieving the ambitious development goals of the project. Full article

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. Full article

Inter-basin water transfer (IBWT) projects are an effective means of addressing regional water resource imbalances. However, owing to the long construction cycle, large investment amount, and wide impact range, water diversion projects exhibit delayed and complex benefits, often lacking clear comprehension. In this study, we established a multi-regional comprehensive benefit assessment framework for the IBWT, considering spatiotemporal and multi-dimensional value effects. Using the South-to-North Water Diversion Project (SNWDP) in China as an example, we assessed its comprehensive benefits from 2003 to 2020. The results showed that the comprehensive benefits of the project were USD 207 billion, encompassing economic and ecological benefits, accounting for 71.6% and 28.4%, respectively. In 2020, the benefits of the SNWDP amounted to USD 39.3 billion, with a per-unit area benefit range of USD −1.03 to 4.27. The operation of the SNWDP effectively alleviated groundwater overexploitation in water-receiving areas. However, without the SNWDP, the total loss caused by industrial development limitations due to water scarcity would have been USD 154.3 billion. These results indicate the importance of a practical framework for assessing IWBT project benefits, aiding managers in assessment tasks, and facilitating the prediction and adjustment of project benefits. Full article