Volume 0,Issue 3,2023 Table of Contents
2023(3):417-426.
Abstract:
In the catchment scale, evapotranspiration refers to the sum of evaporation from water surface and soil, and transpiration of vegetation in a specific region. Evapotranspiration can reflect heat exchange and water exchange between land and atmosphere, and is an important element in hydrological cycle. Therefore, the study of evapotranspiration variation is of great significance to investigate the law of water cycle, the planning and design of hydraulic engineering, and the efficient utilization of water resources. Due to the short time series of evapotranspiration observation, the small number of observation stations, and the heterogeneity of underlying surface at catchment scale, the spatial-temporal distribution of evapotranspiration can not be obtained using the measured data. Scaling up the observed short-term evapotranspiration data at a small scale is an efficient way to get long-term time series at regional scale. To this end, Liulin watershed was selected as the study area in which a large lysimeter was installed in 2021. Penman-Monteith model is a method for calculating reference crop evapotranspiration (ET0) determined by FAO based on the energy balance and water-air diffusion theory, and was employed in the Liulin watershed. Combined with the measured evapotranspiration (ETc) by the lysimeter from June 2020 to May 2021, the crop coefficient (Kc) was calculated by the equation ETc= Kc ×ET0. Studies have shown that crop coefficient (Kc) has a good linear correlation with normalized vegetation index (NDVI), and this relationship has also been used to study evapotranspiration in ecosystems with different crop types and uneven underlying surface. The linear relationship between Kc obtained by the lysimeter and NDVI was established based on the data from June 2020 to May 2021. Then the Kc with the grid size of 250 m was scaled up to Liulin watershed scale from 2000 to 2021 according to the spatial NDVI distribution from 2000 to 2021. Finally, the evapotranspiration with the same spatial and temporal resolution as NDVI in Liulin watershed was obtained. The annual evapotranspiration was also calculated by water balance equation based on long-term observed precipitation and runoff data, in order to verify the feasibility of the proposed evapotranspiration scaling up method. The results showed that: (1) The average annual potential evapotranspiration of Liulin watershed from 2000 to 2021 was 1135.6 mm with a decreasing trend. The average annual actual evapotranspiration was 591.4 mm with an increasing trend. Both the monthly mean potential evapotranspiration and actual evapotranspiration were unimodal, and the peaks occurred in June and July, respectively. (2) Spatially, the annual average evapotranspiration was high in the northwest and low in the southeast, and the spatial distribution characteristics of evapotranspiration in the four seasons were similar with the annual average. The distribution of evapotranspiration was extremely uneven in the four seasons. In summer, evapotranspiration reached 285.9 m, accounting for 48.3% of the whole year, while in winter, evapotranspiration was only 24.2 mm, accounting for 4.1% of the whole year. (3) The annual average crop coefficient of the basin was 0.52, and the spatial variation ranged from 0.34 to 0.73. The crop coefficient in summer was the largest, reaching 0.70, and that in winter was the smallest (0.20). The actual evapotranspiration calculated by the relation between Kc and NDVI was 43.5 mm higher than that calculated by the water balance method, and the relative error from 2000 to 2020 was 7.9% which was acceptable. This error might come from the errors in the fitting relation of crop coefficient under different meteorological conditions. With the increase of actual monitoring data, the relationship between Kc and NDVI can be refined according to different meteorological conditions. The accuracy of the method to calculate the actual evapotranspiration can be further improved. In general, the scaling up method was feasible, and can be applied to other similar regions, and can be tested in different climate zones.
In the catchment scale, evapotranspiration refers to the sum of evaporation from water surface and soil, and transpiration of vegetation in a specific region. Evapotranspiration can reflect heat exchange and water exchange between land and atmosphere, and is an important element in hydrological cycle. Therefore, the study of evapotranspiration variation is of great significance to investigate the law of water cycle, the planning and design of hydraulic engineering, and the efficient utilization of water resources. Due to the short time series of evapotranspiration observation, the small number of observation stations, and the heterogeneity of underlying surface at catchment scale, the spatial-temporal distribution of evapotranspiration can not be obtained using the measured data. Scaling up the observed short-term evapotranspiration data at a small scale is an efficient way to get long-term time series at regional scale. To this end, Liulin watershed was selected as the study area in which a large lysimeter was installed in 2021. Penman-Monteith model is a method for calculating reference crop evapotranspiration (ET0) determined by FAO based on the energy balance and water-air diffusion theory, and was employed in the Liulin watershed. Combined with the measured evapotranspiration (ETc) by the lysimeter from June 2020 to May 2021, the crop coefficient (Kc) was calculated by the equation ETc= Kc ×ET0. Studies have shown that crop coefficient (Kc) has a good linear correlation with normalized vegetation index (NDVI), and this relationship has also been used to study evapotranspiration in ecosystems with different crop types and uneven underlying surface. The linear relationship between Kc obtained by the lysimeter and NDVI was established based on the data from June 2020 to May 2021. Then the Kc with the grid size of 250 m was scaled up to Liulin watershed scale from 2000 to 2021 according to the spatial NDVI distribution from 2000 to 2021. Finally, the evapotranspiration with the same spatial and temporal resolution as NDVI in Liulin watershed was obtained. The annual evapotranspiration was also calculated by water balance equation based on long-term observed precipitation and runoff data, in order to verify the feasibility of the proposed evapotranspiration scaling up method. The results showed that: (1) The average annual potential evapotranspiration of Liulin watershed from 2000 to 2021 was 1135.6 mm with a decreasing trend. The average annual actual evapotranspiration was 591.4 mm with an increasing trend. Both the monthly mean potential evapotranspiration and actual evapotranspiration were unimodal, and the peaks occurred in June and July, respectively. (2) Spatially, the annual average evapotranspiration was high in the northwest and low in the southeast, and the spatial distribution characteristics of evapotranspiration in the four seasons were similar with the annual average. The distribution of evapotranspiration was extremely uneven in the four seasons. In summer, evapotranspiration reached 285.9 m, accounting for 48.3% of the whole year, while in winter, evapotranspiration was only 24.2 mm, accounting for 4.1% of the whole year. (3) The annual average crop coefficient of the basin was 0.52, and the spatial variation ranged from 0.34 to 0.73. The crop coefficient in summer was the largest, reaching 0.70, and that in winter was the smallest (0.20). The actual evapotranspiration calculated by the relation between Kc and NDVI was 43.5 mm higher than that calculated by the water balance method, and the relative error from 2000 to 2020 was 7.9% which was acceptable. This error might come from the errors in the fitting relation of crop coefficient under different meteorological conditions. With the increase of actual monitoring data, the relationship between Kc and NDVI can be refined according to different meteorological conditions. The accuracy of the method to calculate the actual evapotranspiration can be further improved. In general, the scaling up method was feasible, and can be applied to other similar regions, and can be tested in different climate zones.
2023(3):427-434.
Abstract:
With the accelerating expansion of cities and the development of social economy, the shortage of water resources is gradually becoming an obstacle. For northern China, the shortage of water resources is more serious. Industry is the pillar of the national economy. In the rapid development process of industry, it consumes a lot of water resources at the same time. Facing the increasing pressure of industrial water use, scientific and reasonable analysis of the changing law of industrial water use and its driving factors is of great significance to promote the sustainable development of industry. Most of the current research focuses on the water intake and use in the industrial production process, and the research on industrial water dissipation is less, especially on the water dissipation of industrial sub industries. As an important part of urban water dissipation, industrial water dissipation refers to the water directly solidified in products and food during industrial production and transported out of the area and consumed in the process of production activities. The value is equal to the difference between industrial water intake and drainage, which can more intuitively reflect the water dissipation in industrial production.Beijing was taken as the study area, where the problem of water shortage is very prominent. 39 industrial sectors in Beijing were screened and consolidated, and were reconsolidated into 9 departments according to industry similarity: Mining and dressing industry, Food industry, Textile clothing and furniture manufacturing industry, Papermaking printing and stationery manufacturing, Petrochemical industry, Metal smelting and products industry, Mechanical equipment manufacturing, Electricity, steam, hot water, gas, tap water production and supply industry, Other industries. Based on the principle of water balance, the evolution and structure of water dissipation in various industrial sectors were calculated and analyzed. By selecting the relevant indicators that affect industrial water dissipation and establishing the industrial water consumption calculation model, then the model parameters were calibrated with multiple regression method. From 2001 to 2020, with the adjustment of industrial structure and the improvement of water saving level, the industrial water consumption in Beijing has shown a downward trend generally, from 710 million m3/a in 2001 to 227 million m3/a in 2020. In addition to mining and dressing industry, water dissipation of other 8 departments showed a downward trend, among which metal smelting and products industry and textile clothing and furniture manufacturing industry had the most significant decline. Water dissipation in 2020 was 98.1% and 96.2% lower than that in 2001 respectively. Based on the water dissipation and economic data of Beijing’s industrial sectors from 2001 to 2019, the model parameters were calibrated, and the R2 of multiple regression results of industrial sectors was greater than 0.75. The model was verified by the water dissipation and economic data of Beijing’s industrial sectors in 2020. The results showed that the error between the model calculated value and the actual value was all within 10%, and the error between the total industrial water dissipation by summarizing industrial sectors and the actual value was only 1.34%, indicating that the constructed model could better reflect the industrial water dissipation. Industrial water dissipation occurs in the process of industrial water use and is closely related to industrial water use. It is affected by many factors such as economic scale, industrial structure, water use efficiency, and scientific and technological level. Exploring the evolution trend and analyzing the mechanism of water dissipation can provide references for the adjustment of urban industrial structure and rational allocation of water resources in the future.
With the accelerating expansion of cities and the development of social economy, the shortage of water resources is gradually becoming an obstacle. For northern China, the shortage of water resources is more serious. Industry is the pillar of the national economy. In the rapid development process of industry, it consumes a lot of water resources at the same time. Facing the increasing pressure of industrial water use, scientific and reasonable analysis of the changing law of industrial water use and its driving factors is of great significance to promote the sustainable development of industry. Most of the current research focuses on the water intake and use in the industrial production process, and the research on industrial water dissipation is less, especially on the water dissipation of industrial sub industries. As an important part of urban water dissipation, industrial water dissipation refers to the water directly solidified in products and food during industrial production and transported out of the area and consumed in the process of production activities. The value is equal to the difference between industrial water intake and drainage, which can more intuitively reflect the water dissipation in industrial production.Beijing was taken as the study area, where the problem of water shortage is very prominent. 39 industrial sectors in Beijing were screened and consolidated, and were reconsolidated into 9 departments according to industry similarity: Mining and dressing industry, Food industry, Textile clothing and furniture manufacturing industry, Papermaking printing and stationery manufacturing, Petrochemical industry, Metal smelting and products industry, Mechanical equipment manufacturing, Electricity, steam, hot water, gas, tap water production and supply industry, Other industries. Based on the principle of water balance, the evolution and structure of water dissipation in various industrial sectors were calculated and analyzed. By selecting the relevant indicators that affect industrial water dissipation and establishing the industrial water consumption calculation model, then the model parameters were calibrated with multiple regression method. From 2001 to 2020, with the adjustment of industrial structure and the improvement of water saving level, the industrial water consumption in Beijing has shown a downward trend generally, from 710 million m3/a in 2001 to 227 million m3/a in 2020. In addition to mining and dressing industry, water dissipation of other 8 departments showed a downward trend, among which metal smelting and products industry and textile clothing and furniture manufacturing industry had the most significant decline. Water dissipation in 2020 was 98.1% and 96.2% lower than that in 2001 respectively. Based on the water dissipation and economic data of Beijing’s industrial sectors from 2001 to 2019, the model parameters were calibrated, and the R2 of multiple regression results of industrial sectors was greater than 0.75. The model was verified by the water dissipation and economic data of Beijing’s industrial sectors in 2020. The results showed that the error between the model calculated value and the actual value was all within 10%, and the error between the total industrial water dissipation by summarizing industrial sectors and the actual value was only 1.34%, indicating that the constructed model could better reflect the industrial water dissipation. Industrial water dissipation occurs in the process of industrial water use and is closely related to industrial water use. It is affected by many factors such as economic scale, industrial structure, water use efficiency, and scientific and technological level. Exploring the evolution trend and analyzing the mechanism of water dissipation can provide references for the adjustment of urban industrial structure and rational allocation of water resources in the future.
2023(3):435-446.
Abstract:
Surface water and groundwater are closely related hydrologic units, both are an important part of water resources and have complex water exchange. The interaction between surface water and groundwater is influenced by topographic features, climate change, and human activities. The distribution of the chemical composition of surface-subsurface on a spatial scale increased by the complexity of hydrological conditions. Therefore, a scientific understanding of the surface-groundwater conversion relationship is an important basis for the sustainable development of water resources and the protection of the ecological environment.With the development of computer technology, hydrological models came to be an important means to understand and quantify surface and subsurface hydrological processes. They integrate the governing equation of flow motion and are solved by the numerical solution method. Especially the physics-based surface-subsurface coupling model can comprehensively consider the interrelation of overland flow, vadose zone, saturated zone, and channel flow, and has become an important tool to understand the comprehensive hydrological process.An extensive literature review was made through a systematically summarization, the common governing equations of the surface zone, vadose zone, groundwater, and river were sorted out, and the numerical solution methods of finite difference, finite element, and finite volume method. It is pointed out that the single groundwater model and single surface water model have shortcomings in quantifying the amount of water conversion between surface and subsurface. A total of 11 commonly used surface-subsurface models were summarized in detail, and the characteristics and applicable directions of each model were explained. These coupled models are classified as loosely coupled, semi-loosely coupled, and tightly coupled models based on the coupling methods. Coupled models have been widely used in the analysis of surface water - groundwater transfer relationship under environmental changes, the research of river ecological base flow, and the analysis of joint dispatch of surface water and groundwater.It is suggested that the researcher can focus following topics in future research, such as (1) the analysis of the specific mechanisms of surface-subsurface interaction in complex geomorphic areas. (2) Make full use of remote sensing technology and enrich the means of obtaining hydrological parameters. (3) Enhancement of model identification and verification, to explore multi-state, multi-factor methods, select appropriate time steps of verification data, and ensure the data quality. (4) Alternative models could also be considered as well to reduce the cost of repeatedly invoking the model and to improve the simulation efficiency. (5) Integration of model coupling with cross-discipline to realize the application in multiple fields.
Surface water and groundwater are closely related hydrologic units, both are an important part of water resources and have complex water exchange. The interaction between surface water and groundwater is influenced by topographic features, climate change, and human activities. The distribution of the chemical composition of surface-subsurface on a spatial scale increased by the complexity of hydrological conditions. Therefore, a scientific understanding of the surface-groundwater conversion relationship is an important basis for the sustainable development of water resources and the protection of the ecological environment.With the development of computer technology, hydrological models came to be an important means to understand and quantify surface and subsurface hydrological processes. They integrate the governing equation of flow motion and are solved by the numerical solution method. Especially the physics-based surface-subsurface coupling model can comprehensively consider the interrelation of overland flow, vadose zone, saturated zone, and channel flow, and has become an important tool to understand the comprehensive hydrological process.An extensive literature review was made through a systematically summarization, the common governing equations of the surface zone, vadose zone, groundwater, and river were sorted out, and the numerical solution methods of finite difference, finite element, and finite volume method. It is pointed out that the single groundwater model and single surface water model have shortcomings in quantifying the amount of water conversion between surface and subsurface. A total of 11 commonly used surface-subsurface models were summarized in detail, and the characteristics and applicable directions of each model were explained. These coupled models are classified as loosely coupled, semi-loosely coupled, and tightly coupled models based on the coupling methods. Coupled models have been widely used in the analysis of surface water - groundwater transfer relationship under environmental changes, the research of river ecological base flow, and the analysis of joint dispatch of surface water and groundwater.It is suggested that the researcher can focus following topics in future research, such as (1) the analysis of the specific mechanisms of surface-subsurface interaction in complex geomorphic areas. (2) Make full use of remote sensing technology and enrich the means of obtaining hydrological parameters. (3) Enhancement of model identification and verification, to explore multi-state, multi-factor methods, select appropriate time steps of verification data, and ensure the data quality. (4) Alternative models could also be considered as well to reduce the cost of repeatedly invoking the model and to improve the simulation efficiency. (5) Integration of model coupling with cross-discipline to realize the application in multiple fields.
2023(3):447-456,479.
Abstract:
Reservoir construction and operation disturbance effects on downstream can not be ignored. Hydrologic alteration analysis is an effective way to reflect the impact of human activities on the hydrologic regime. Currently, the widely used hydrologic regime analysis methods are mostly derived from hydrologic alteration (IHA) indicators. However, each method has its advantages and disadvantages. Different evaluation results by these methods indicate that the hydrologic variability analysis is subject to a high degree of uncertainty. Due to the different characteristics of the assessment units, it is still uncertain to determine which method is the most reasonable. Therefore, it is necessary to find a reliable evaluation method for hydrologic regime alteration.Four evaluation methods of hydrologic regime alteration, i.e., the range of variability approach (RVA), histogram matching approach (HMA), histogram comparison approach (HCA), and revised range of variability approach (RRVA) were selected for analysis and comparison. The natural daily flow series from 1954 to 2021 and the measured flow from 1974 to 2021 at Huangjiagang hydrological station were used to analyze the hydrologic regime alteration after the operation of Danjiangkou Reservoir. Application results of the four methods are similar and could confirm each other, but also had their own merits and limitations. The RVA has mathematical drawbacks and ignores the specific variability of the IHA within and outside the target range. Both the HMA and HCA use frequency histograms to describe IHA, which could show the full range distribution of IHA values. HCA, as an improved version of HMA, has more reasonable and comprehensive results. Based on considering frequency difference, RRVA takes into account the morphological changes of IHA, including multiple characteristics such as time, magnitude, etc., so its evaluation results are the largest.Therefore, a novel comprehensive hydrologic alteration evaluation method is proposed, which is the combination of RRVA and HCA methods with different weights based on subjective and objective information. The comprehensive evaluation results of the hydrologic variability degree are analyzed in more detail by the frequency histogram of each indicator. It has the following four advantages: preserve the distribution information of all intervals of IHAs through frequency histogram; avoid abnormal extreme results of hydrologic alternation; consider the morphological change and spatial-temporal differences of the hydrologic regime; reduce the result uncertainty effectively. The comprehensive evaluation results showed that the changes after the construction of Danjiangkou Reservoir conformed to the operation law of flood storage and dry compensation. The flow increased significantly in the dry season and decreased significantly in the flood season. The change degree of monthly average flow was 41.28%, and the change degree of extreme flow conditions was 64.83%. Moreover, the rate and frequency of water conditions changed highly, which was 80.53%. After the implementation of the middle route of the South-to-North Water Transfer Project, the flow showed a downward trend, indicating that the available water resources in the middle and lower reaches of the Han River were reduced. The overall hydrologic regime alteration at Huangjiagang hydrological station was 55.70%, which represented a moderate change.The comprehensive hydrologic alteration evaluation method could reduce the uncertainty of the results, capture more information on IHAs before and after human impact, and provide reliable data for ecological restoration and operation, etc. The operation of the Danjiangkou Reservoir has changed the natural flow regime and caused pressure on the natural habitat in the middle and lower reaches of the Han River, which requires measures to restore its ecology.
Reservoir construction and operation disturbance effects on downstream can not be ignored. Hydrologic alteration analysis is an effective way to reflect the impact of human activities on the hydrologic regime. Currently, the widely used hydrologic regime analysis methods are mostly derived from hydrologic alteration (IHA) indicators. However, each method has its advantages and disadvantages. Different evaluation results by these methods indicate that the hydrologic variability analysis is subject to a high degree of uncertainty. Due to the different characteristics of the assessment units, it is still uncertain to determine which method is the most reasonable. Therefore, it is necessary to find a reliable evaluation method for hydrologic regime alteration.Four evaluation methods of hydrologic regime alteration, i.e., the range of variability approach (RVA), histogram matching approach (HMA), histogram comparison approach (HCA), and revised range of variability approach (RRVA) were selected for analysis and comparison. The natural daily flow series from 1954 to 2021 and the measured flow from 1974 to 2021 at Huangjiagang hydrological station were used to analyze the hydrologic regime alteration after the operation of Danjiangkou Reservoir. Application results of the four methods are similar and could confirm each other, but also had their own merits and limitations. The RVA has mathematical drawbacks and ignores the specific variability of the IHA within and outside the target range. Both the HMA and HCA use frequency histograms to describe IHA, which could show the full range distribution of IHA values. HCA, as an improved version of HMA, has more reasonable and comprehensive results. Based on considering frequency difference, RRVA takes into account the morphological changes of IHA, including multiple characteristics such as time, magnitude, etc., so its evaluation results are the largest.Therefore, a novel comprehensive hydrologic alteration evaluation method is proposed, which is the combination of RRVA and HCA methods with different weights based on subjective and objective information. The comprehensive evaluation results of the hydrologic variability degree are analyzed in more detail by the frequency histogram of each indicator. It has the following four advantages: preserve the distribution information of all intervals of IHAs through frequency histogram; avoid abnormal extreme results of hydrologic alternation; consider the morphological change and spatial-temporal differences of the hydrologic regime; reduce the result uncertainty effectively. The comprehensive evaluation results showed that the changes after the construction of Danjiangkou Reservoir conformed to the operation law of flood storage and dry compensation. The flow increased significantly in the dry season and decreased significantly in the flood season. The change degree of monthly average flow was 41.28%, and the change degree of extreme flow conditions was 64.83%. Moreover, the rate and frequency of water conditions changed highly, which was 80.53%. After the implementation of the middle route of the South-to-North Water Transfer Project, the flow showed a downward trend, indicating that the available water resources in the middle and lower reaches of the Han River were reduced. The overall hydrologic regime alteration at Huangjiagang hydrological station was 55.70%, which represented a moderate change.The comprehensive hydrologic alteration evaluation method could reduce the uncertainty of the results, capture more information on IHAs before and after human impact, and provide reliable data for ecological restoration and operation, etc. The operation of the Danjiangkou Reservoir has changed the natural flow regime and caused pressure on the natural habitat in the middle and lower reaches of the Han River, which requires measures to restore its ecology.
2023(3):457-469.
Abstract:
Parameter optimization is a crucial part of hydrological model simulation, which determines the accuracy of simulation and forecast.The Soil and Water Assessment Tool (SWAT) model is a distributed basin hydrological model based on the physical mechanism, and in the study of basin runoff simulation using the SWAT model, the model parameter optimization is mainly determined by the SWAT Calibration Uncertainties Program (SWAT-CUP) automatic rate method, including the SUFI-2 algorithm, Particle Swarm Optimization (PSO) algorithm, Parasol algorithm and General Language Understanding Evaluation (GLUE) algorithm. SWAT models often require thousands of hydrological model runs through the parameter optimization process to find a satisfactory combination of parameters. In recent years, in-depth studies on parameter optimization have concluded that the uniqueness of the optimal parameters is difficult to achieve, the problem of different reference effect is inevitable, so a common practice is to consider the parameter solutions as probability distributions that can be solved by applying mathematical methods.When the SUFI-2 algorithm is used for parameter optimization, it is found that the results often show uncertainties caused by different reference effect, or the runoff extremes are not well simulated.SOM algorithm is a neural network algorithm based on unsupervised learning, which can achieve intelligent clustering of data through self-organized competitive learning without understanding the interrelationship between sample data, and is also for achieving clustering through data mining technology. In practical engineering problems, taking the clustering analysis method can simplify the complex data system, make the data computation processing efficient, and make the internal laws of things clear. The SOM clustering algorithm was applied to the process of SWAT model parameter optimization to reduce the parameter estimation uncertainty. The sensitivity analysis method was used to select key parameters, Latin hypercube sampling was used to construct a parameter sample set for key parameters, and then combining the simulation accuracy indexes under each group of key parameter combinations to construct clustering index sets, the SOM clustering algorithm was used for clustering, and a SWAT model key parameter optimization system method was formed by identifying the range of each key parameter taking values based on the higher simulation accuracy and less fluctuation category. Taking the Shitoukoumen Reservoir basin as an example, the monthly runoff actual measurement data from 1980 to 2016 (1980 to 1986 as the preheating period, 1987 to 2009 as the rating period, and 2010 to 2016 as the validation period) were selected to establish the SWAT model, used the SOM clustering algorithm for parameter optimization, continuously narrow the reasonable value interval of the key parameters, and compare with the simulation results using the SUFI -2 algorithm. The results showed that the SWAT model is suitable for the Shitoukoumen Reservoir basin,R2 is 0.79,ENSis 0.74,P-factor is 0.65 and R- factor is 0.56 in the validation period before parameter optimization. The R2 is 0.88,ENS is 0.83,P-factor is 0.70 and R -factor is 0.50 in the validation period after parameter optimization. The simulation effect was satisfactory.Therefore, the application of SOM algorithm for SWAT model parameter optimization can reduce model uncertainty, improve runoff simulation accuracy, and provide ideas for the selection of hydrological model parameter optimization algorithm, which is important for water resources management policy formulation and reservoir optimization scheduling.
Parameter optimization is a crucial part of hydrological model simulation, which determines the accuracy of simulation and forecast.The Soil and Water Assessment Tool (SWAT) model is a distributed basin hydrological model based on the physical mechanism, and in the study of basin runoff simulation using the SWAT model, the model parameter optimization is mainly determined by the SWAT Calibration Uncertainties Program (SWAT-CUP) automatic rate method, including the SUFI-2 algorithm, Particle Swarm Optimization (PSO) algorithm, Parasol algorithm and General Language Understanding Evaluation (GLUE) algorithm. SWAT models often require thousands of hydrological model runs through the parameter optimization process to find a satisfactory combination of parameters. In recent years, in-depth studies on parameter optimization have concluded that the uniqueness of the optimal parameters is difficult to achieve, the problem of different reference effect is inevitable, so a common practice is to consider the parameter solutions as probability distributions that can be solved by applying mathematical methods.When the SUFI-2 algorithm is used for parameter optimization, it is found that the results often show uncertainties caused by different reference effect, or the runoff extremes are not well simulated.SOM algorithm is a neural network algorithm based on unsupervised learning, which can achieve intelligent clustering of data through self-organized competitive learning without understanding the interrelationship between sample data, and is also for achieving clustering through data mining technology. In practical engineering problems, taking the clustering analysis method can simplify the complex data system, make the data computation processing efficient, and make the internal laws of things clear. The SOM clustering algorithm was applied to the process of SWAT model parameter optimization to reduce the parameter estimation uncertainty. The sensitivity analysis method was used to select key parameters, Latin hypercube sampling was used to construct a parameter sample set for key parameters, and then combining the simulation accuracy indexes under each group of key parameter combinations to construct clustering index sets, the SOM clustering algorithm was used for clustering, and a SWAT model key parameter optimization system method was formed by identifying the range of each key parameter taking values based on the higher simulation accuracy and less fluctuation category. Taking the Shitoukoumen Reservoir basin as an example, the monthly runoff actual measurement data from 1980 to 2016 (1980 to 1986 as the preheating period, 1987 to 2009 as the rating period, and 2010 to 2016 as the validation period) were selected to establish the SWAT model, used the SOM clustering algorithm for parameter optimization, continuously narrow the reasonable value interval of the key parameters, and compare with the simulation results using the SUFI -2 algorithm. The results showed that the SWAT model is suitable for the Shitoukoumen Reservoir basin,R2 is 0.79,ENSis 0.74,P-factor is 0.65 and R- factor is 0.56 in the validation period before parameter optimization. The R2 is 0.88,ENS is 0.83,P-factor is 0.70 and R -factor is 0.50 in the validation period after parameter optimization. The simulation effect was satisfactory.Therefore, the application of SOM algorithm for SWAT model parameter optimization can reduce model uncertainty, improve runoff simulation accuracy, and provide ideas for the selection of hydrological model parameter optimization algorithm, which is important for water resources management policy formulation and reservoir optimization scheduling.
2023(3):470-479.
Abstract:
Based on the principles of multi-objective planning, fuzzy planning and interval planning, with the goal of maximizing economic, social and environmental benefits, and taking water demand, water availability and water fairness between water departments in different sub-districts as the main constraints, a multi-objective fuzzy planning model based on uncertainty suitable for multiple water sources, multiple sub-areas and multiple users is constructed, and strives to balance the amount of user-allocated water in the water resources allocation system. The relationship between water shortage risk and system benefits maximizes the comprehensive benefits of the system. The model transforms the multi-objective program into a single-objective program by introducing a fuzzy membership function and using a two-step interactive algorithm. The model is also applied to the optimal allocation of water resources in Hengshui City, Hebei Province, and an optimal water allocation plan for 11 sub-areas, four water sources and four water consuming industries is obtained for the planning level in 2020. The results indicate that the method can be used to study the optimal allocation of water resources between multi-source, multi-area, and multi-water sectors. The optimal model achieves complementarity between multiple water sources and multiple objectives, and provides a decision-making basis for optimal allocation of water resources in arid and water-deficient areas. At the same time, after considering the fairness constraint of water use, under the condition of water shortage, the flow of water resources to regions and sectors with high unilateral water efficiency can be effectively controlled, which is conducive to multi-regional and multi-sectoral sharing of water shortage risks. The research results can provide technical reference for the optimal allocation of water resources in other counties in Hebei Province.
Based on the principles of multi-objective planning, fuzzy planning and interval planning, with the goal of maximizing economic, social and environmental benefits, and taking water demand, water availability and water fairness between water departments in different sub-districts as the main constraints, a multi-objective fuzzy planning model based on uncertainty suitable for multiple water sources, multiple sub-areas and multiple users is constructed, and strives to balance the amount of user-allocated water in the water resources allocation system. The relationship between water shortage risk and system benefits maximizes the comprehensive benefits of the system. The model transforms the multi-objective program into a single-objective program by introducing a fuzzy membership function and using a two-step interactive algorithm. The model is also applied to the optimal allocation of water resources in Hengshui City, Hebei Province, and an optimal water allocation plan for 11 sub-areas, four water sources and four water consuming industries is obtained for the planning level in 2020. The results indicate that the method can be used to study the optimal allocation of water resources between multi-source, multi-area, and multi-water sectors. The optimal model achieves complementarity between multiple water sources and multiple objectives, and provides a decision-making basis for optimal allocation of water resources in arid and water-deficient areas. At the same time, after considering the fairness constraint of water use, under the condition of water shortage, the flow of water resources to regions and sectors with high unilateral water efficiency can be effectively controlled, which is conducive to multi-regional and multi-sectoral sharing of water shortage risks. The research results can provide technical reference for the optimal allocation of water resources in other counties in Hebei Province.
2023(3):480-490.
Abstract:
The water cycle is one of the most significant hubs in the interaction among ocean, land and atmosphere, playing a crucial role in how global climate and ecological environment evolved. Watershed hydrological systems have been significantly altered by global climate change and human activities in recent decades. As a result, the attribution analysis of runoff changes in watersheds under the dynamic landscape and the quantitative identification of the contribution rate of the core driving factors of runoff change have emerged as the main research topics for scholars at home and abroad. The Budyko hypothesis-based elastic coefficient approach had been acknowledged as an effective technique for attribution analysis of runoff change, with the attributes of straight forward computation and a clear explanation of physical concepts. Hence, the Buha River basin, a climate change-sensitive region in the northeastern Qinghai-Tibet Plateau is chosen as the research object. Based on the water-heat coupling equilibrium theory of Budyko hypothesis, the contribution of various factors to the change in basin runoff is analyzed and quantified. A scientific foundation for further exploring the hydrological evolution law of the basin and water resources planning is thus formed.Based on the hydrometeorological data of precipitation, runoff and temperature from 1958 to 2018, moving average and linear estimate techniques were used to analyze the trend of the hydrometeorological components. The mutational characteristics of runoff series were analyzed and identified by applying the Mann-Kendall trend test technique and the Pettitt Test method. Derived from the theory of the water-heat coupling equilibrium equation under the Budyko hypothesis, the contribution of various factors to runoff change was analyzed and quantified, and the influence of precipitation intensity, potential evapotranspiration, and underlying surface change on runoff change was quantitatively evaluated, with the main driving factors of runoff change identified. In the Buha River basin, the features of alternating increase and decrease had been indicated from the interannual variation of climatic variables, and the fluctuation grew from 1958 to 2018. An upward trend can be obviously seen from potential evapotranspiration, precipitation, and annual runoff depth, with increased rate of 0.825 mm/a, 1.416 mm/a and 0.536 mm/a respectively. The runoff mutation took place in 2001. Therefore, the runoff sequence was divided into two periods: the reference period (1958-2001) and the change period (2002-2018). The average runoff depth increased by 32.7 mm during the changing period to 83.3 mm, with a 64.5% relative change rate from the reference period. The precipitation increased by 86.4 mm compared with the base period, and the relative change rate was 26.8%. In comparison to the base period, the potential evapotranspiration increased by 50.3 mm, and the relative change rate was 5.5%. The runoff coefficient (R/P) increased compared to the base period, while the drought index (E0/P) declined. Both were greater than 1.0, indicating that the research region was an arid area, nevertheless the dryness decreased year by year. The elastic coefficients of runoff to precipitation, potential evapotranspiration and underlying surface suggested that the Buha River basin was sensitive to the change in precipitation and insensitive to alter potential evapotranspiration, with value of 2.35, ?0.98 and ?1.73 respectively. There has been little change and relative stability in the main land use types, yet there has been some slight variation between them.Precipitation had the greatest influence on runoff, with a contribution rate of 97.12%, accounting for 86.27% of the total. Potential evapotranspiration was contributing at a rate of ?10.85%, and underlying surface was contributing at a rate of 13.73% to runoff. While potential evapotranspiration has a negative impact on the rise in runoff, a positive contribution can be found in the change of precipitation and the underlying surface. The change in precipitation is the main influencing factor of runoff increase in Buha River basin, followed by changes in underlying surface, while the impact of potential evapotranspiration was minimal.Buha?River；Budyko?water-energy?equation；attribution?analysis；runoff?variation；elastic?coefficient
The water cycle is one of the most significant hubs in the interaction among ocean, land and atmosphere, playing a crucial role in how global climate and ecological environment evolved. Watershed hydrological systems have been significantly altered by global climate change and human activities in recent decades. As a result, the attribution analysis of runoff changes in watersheds under the dynamic landscape and the quantitative identification of the contribution rate of the core driving factors of runoff change have emerged as the main research topics for scholars at home and abroad. The Budyko hypothesis-based elastic coefficient approach had been acknowledged as an effective technique for attribution analysis of runoff change, with the attributes of straight forward computation and a clear explanation of physical concepts. Hence, the Buha River basin, a climate change-sensitive region in the northeastern Qinghai-Tibet Plateau is chosen as the research object. Based on the water-heat coupling equilibrium theory of Budyko hypothesis, the contribution of various factors to the change in basin runoff is analyzed and quantified. A scientific foundation for further exploring the hydrological evolution law of the basin and water resources planning is thus formed.Based on the hydrometeorological data of precipitation, runoff and temperature from 1958 to 2018, moving average and linear estimate techniques were used to analyze the trend of the hydrometeorological components. The mutational characteristics of runoff series were analyzed and identified by applying the Mann-Kendall trend test technique and the Pettitt Test method. Derived from the theory of the water-heat coupling equilibrium equation under the Budyko hypothesis, the contribution of various factors to runoff change was analyzed and quantified, and the influence of precipitation intensity, potential evapotranspiration, and underlying surface change on runoff change was quantitatively evaluated, with the main driving factors of runoff change identified. In the Buha River basin, the features of alternating increase and decrease had been indicated from the interannual variation of climatic variables, and the fluctuation grew from 1958 to 2018. An upward trend can be obviously seen from potential evapotranspiration, precipitation, and annual runoff depth, with increased rate of 0.825 mm/a, 1.416 mm/a and 0.536 mm/a respectively. The runoff mutation took place in 2001. Therefore, the runoff sequence was divided into two periods: the reference period (1958-2001) and the change period (2002-2018). The average runoff depth increased by 32.7 mm during the changing period to 83.3 mm, with a 64.5% relative change rate from the reference period. The precipitation increased by 86.4 mm compared with the base period, and the relative change rate was 26.8%. In comparison to the base period, the potential evapotranspiration increased by 50.3 mm, and the relative change rate was 5.5%. The runoff coefficient (R/P) increased compared to the base period, while the drought index (E0/P) declined. Both were greater than 1.0, indicating that the research region was an arid area, nevertheless the dryness decreased year by year. The elastic coefficients of runoff to precipitation, potential evapotranspiration and underlying surface suggested that the Buha River basin was sensitive to the change in precipitation and insensitive to alter potential evapotranspiration, with value of 2.35, ?0.98 and ?1.73 respectively. There has been little change and relative stability in the main land use types, yet there has been some slight variation between them.Precipitation had the greatest influence on runoff, with a contribution rate of 97.12%, accounting for 86.27% of the total. Potential evapotranspiration was contributing at a rate of ?10.85%, and underlying surface was contributing at a rate of 13.73% to runoff. While potential evapotranspiration has a negative impact on the rise in runoff, a positive contribution can be found in the change of precipitation and the underlying surface. The change in precipitation is the main influencing factor of runoff increase in Buha River basin, followed by changes in underlying surface, while the impact of potential evapotranspiration was minimal.Buha?River；Budyko?water-energy?equation；attribution?analysis；runoff?variation；elastic?coefficient
2023(3):491-500.
Abstract:
The Shichuan River Valley is located in the hinterland of Guanzhong, and due to the shortage of surface water resources, groundwater is an important source of supply for the area. The long-term imbalance of groundwater extraction and replenishment led to multiple landing funnels in the area, resulting in the drying up of submerged aquifers on a large scale and the loss of ecological service function value of rivers. Artificial recharge is an important measure to solve the contradiction between water supply and demand in the area, prevent and control groundwater overdraft, and conserve water resources. The large underground storage space in the area provides favorable conditions for artificial groundwater recharge. The study relies on the Shaanxi Water Conservancy Science and Technology Project, through field investigation and collection of information covering topography and geomorphology, hydro-meteorology, river system, stratigraphic lithology, hydrogeological conditions and current status of groundwater development and utilization in the study area to provide a supporting basis for the subsequent study of artificial groundwater recharge.The artificial recharge conditions in the study area were comprehensively analyzed, and according to the basic principles of index selection, six indexes of groundwater table depth of burial, slope, aquifer thickness, distance to environmentally sensitive areas, aquifer permeability coefficient, and water supply degree were selected for graded scoring. Then, the AHP method was used to calculate the subjective weights and the CRITIC method to calculate the objective weights, respectively. After that, the subjective weights and objective weights of each index were combined using the formula to obtain the coupling weights. Based on the determination of weights, the raster data of each index was overlaid and calculated using ArcGIS spatial analysis technology to obtain the recharge potential scores of each area of the Shichuan River groundwater reservoir, and established a recharge suitability evaluation system that fit the characteristics of the area to determine the site selection of the recharge area. On this basis, a three-dimensional geological model of the study area was established by combining the borehole data and geological profiles, and the spatial structure and stratigraphic characteristics of the regional submerged aquifer were analyzed and studied to determine the characteristics and layout requirements of each recharge process and to select the most suitable recharge mode for the area. The results showed that the high potential area suitable for artificial recharge was concentrated in the central and western parts of the study area, with an area of 16.49 km2, accounting for 10.99%; the higher potential area was scattered, mainly in the northeast and southwest of the high potential area and the southeast of the study area, with an area of 31.52 km2, accounting for 21.01%; the medium potential area was widely distributed, mainly in the northwest and most of the southeast of the study area, with an area of 68.75 km2, accounting for 45.83%. Both high potential and higher potential areas can be the primary choice for recharge sites for recharge, with medium potential as a supplemental area. Among them, it was appropriate to construct surface infiltration ponds or seepage pits in the northern part of the high potential and higher potential area in the middle and upper reaches of the Shichuan River channel; reverse filtration recharge well clusters can be placed in the southern part of the high potential and higher potential areas in the middle and upper reaches of the river and in the higher potential areas in the middle and lower reaches of the river; a seepage canal about 4.5 km long can be arranged along the middle and upper reaches of the Shichuan River channel between the high potential and higher potential areas to use the river channel for infiltration recharge. The results of the study can provide a reference for the construction of underground reservoirs.
The Shichuan River Valley is located in the hinterland of Guanzhong, and due to the shortage of surface water resources, groundwater is an important source of supply for the area. The long-term imbalance of groundwater extraction and replenishment led to multiple landing funnels in the area, resulting in the drying up of submerged aquifers on a large scale and the loss of ecological service function value of rivers. Artificial recharge is an important measure to solve the contradiction between water supply and demand in the area, prevent and control groundwater overdraft, and conserve water resources. The large underground storage space in the area provides favorable conditions for artificial groundwater recharge. The study relies on the Shaanxi Water Conservancy Science and Technology Project, through field investigation and collection of information covering topography and geomorphology, hydro-meteorology, river system, stratigraphic lithology, hydrogeological conditions and current status of groundwater development and utilization in the study area to provide a supporting basis for the subsequent study of artificial groundwater recharge.The artificial recharge conditions in the study area were comprehensively analyzed, and according to the basic principles of index selection, six indexes of groundwater table depth of burial, slope, aquifer thickness, distance to environmentally sensitive areas, aquifer permeability coefficient, and water supply degree were selected for graded scoring. Then, the AHP method was used to calculate the subjective weights and the CRITIC method to calculate the objective weights, respectively. After that, the subjective weights and objective weights of each index were combined using the formula to obtain the coupling weights. Based on the determination of weights, the raster data of each index was overlaid and calculated using ArcGIS spatial analysis technology to obtain the recharge potential scores of each area of the Shichuan River groundwater reservoir, and established a recharge suitability evaluation system that fit the characteristics of the area to determine the site selection of the recharge area. On this basis, a three-dimensional geological model of the study area was established by combining the borehole data and geological profiles, and the spatial structure and stratigraphic characteristics of the regional submerged aquifer were analyzed and studied to determine the characteristics and layout requirements of each recharge process and to select the most suitable recharge mode for the area. The results showed that the high potential area suitable for artificial recharge was concentrated in the central and western parts of the study area, with an area of 16.49 km2, accounting for 10.99%; the higher potential area was scattered, mainly in the northeast and southwest of the high potential area and the southeast of the study area, with an area of 31.52 km2, accounting for 21.01%; the medium potential area was widely distributed, mainly in the northwest and most of the southeast of the study area, with an area of 68.75 km2, accounting for 45.83%. Both high potential and higher potential areas can be the primary choice for recharge sites for recharge, with medium potential as a supplemental area. Among them, it was appropriate to construct surface infiltration ponds or seepage pits in the northern part of the high potential and higher potential area in the middle and upper reaches of the Shichuan River channel; reverse filtration recharge well clusters can be placed in the southern part of the high potential and higher potential areas in the middle and upper reaches of the river and in the higher potential areas in the middle and lower reaches of the river; a seepage canal about 4.5 km long can be arranged along the middle and upper reaches of the Shichuan River channel between the high potential and higher potential areas to use the river channel for infiltration recharge. The results of the study can provide a reference for the construction of underground reservoirs.
2023(3):501-511.
Abstract:
In recent years, the flood situation in the Pearl River Delta has changed significantly due to the change of water and sediment conditions from the upstream and the impact of human activities. On the one hand, the construction of the upstream embankment reduces the flood detention volume and increases the energy of flood movement in the main river channel, resulting in an increase in the peak flow of the downstream section, a rise in water level and a steep increase in flood control pressure. On the other hand, since the 1980s, due to the impact of human activities such as large-scale and high-intensity artificial sand mining and channel excavation, the riverbed of the Pearl River Delta has been generally cut down, and the river channel has developed into a narrow and deep type. Under the condition that the incoming flow has little change and the incoming sediment volume has dropped significantly, the water level at the same flow has dropped significantly, and the flood discharge capacity of the river channel has improved. The design flood in the river network area has changed greatly due to the influence of water level rise caused by the basin flood returning to the channel and water level drop caused by the regional riverbed undercutting. In this case, a new flood control system must be rapidly reconstructed under the changed conditions to find a new "balance" point.The current situation of flood diversion and terrain downcutting is analyzed to explore the impact and change using flood and terrain measurement data. Based on a two-dimensional hydrodynamic model of the river network, the effects of flood diversion and terrain downcutting on the flood discharge capacity of the West and North River Delta are quantified, and the current flow capacity of the main river channel is evaluated.The results shows that: ① The flood control pressure of the Pearl River Delta increases sharply as the result of the flood returning to main channel. Compared with the 1990s, the design peak flow of the flood control section Sixianjiao with a 50 year return period has increased by 11.7%, and the maximum rise of the corresponding flood levels in the West and North River is 0.67 m and 0.56 m respectively.② The large-scale downcutting of the river channel increases the flood discharge capacity. From 1999 to 2016, the average downcut amplitude of the main channel of the West River and the North River is 2.54 m and 1.21 m respectively, and the corresponding flood water level generally decreases. The maximum drop of flood level with 50 year return period frequency is 0.76 m in West River and 0.67 m in North River.③ Except for the upper reaches of the delta, the effect of flood returning to main channel on the rise of flood level in the Pearl River Delta is significantly greater than that of channel deepening. At present, the design water level of the main river course in the delta is mostly 50 year return period. The water level of nearly 900 km reaches exceeds the design water level of the embankment, which is mainly concentrated in the hinterland of the delta near Tianhe, Nanhua and Sanshanjiao.The main conclusions are: ① The return of flood to the channel will cause significant rise of flood level; ② The undercutting of river bed will cause the flood level to decrease generally; ③ Considering the influence of flood return channel and river channel topographic undercutting, flood return channel has basically greater effect on water level rise than river bed undercutting; ④ Under the combined influence of flood channeling and uneven topographic undercutting, abnormal backwater of water level in the abdomen still exists. The rapid contraction of the overflow section along the river and the formation of the bottleneck section are the main reasons for the abnormal backwater of the water level in the abdomen since 1999. The research results can provide basis and technical support for the subsequent overall safety assessment and improvement of the Pearl River Delta flood control system.
In recent years, the flood situation in the Pearl River Delta has changed significantly due to the change of water and sediment conditions from the upstream and the impact of human activities. On the one hand, the construction of the upstream embankment reduces the flood detention volume and increases the energy of flood movement in the main river channel, resulting in an increase in the peak flow of the downstream section, a rise in water level and a steep increase in flood control pressure. On the other hand, since the 1980s, due to the impact of human activities such as large-scale and high-intensity artificial sand mining and channel excavation, the riverbed of the Pearl River Delta has been generally cut down, and the river channel has developed into a narrow and deep type. Under the condition that the incoming flow has little change and the incoming sediment volume has dropped significantly, the water level at the same flow has dropped significantly, and the flood discharge capacity of the river channel has improved. The design flood in the river network area has changed greatly due to the influence of water level rise caused by the basin flood returning to the channel and water level drop caused by the regional riverbed undercutting. In this case, a new flood control system must be rapidly reconstructed under the changed conditions to find a new "balance" point.The current situation of flood diversion and terrain downcutting is analyzed to explore the impact and change using flood and terrain measurement data. Based on a two-dimensional hydrodynamic model of the river network, the effects of flood diversion and terrain downcutting on the flood discharge capacity of the West and North River Delta are quantified, and the current flow capacity of the main river channel is evaluated.The results shows that: ① The flood control pressure of the Pearl River Delta increases sharply as the result of the flood returning to main channel. Compared with the 1990s, the design peak flow of the flood control section Sixianjiao with a 50 year return period has increased by 11.7%, and the maximum rise of the corresponding flood levels in the West and North River is 0.67 m and 0.56 m respectively.② The large-scale downcutting of the river channel increases the flood discharge capacity. From 1999 to 2016, the average downcut amplitude of the main channel of the West River and the North River is 2.54 m and 1.21 m respectively, and the corresponding flood water level generally decreases. The maximum drop of flood level with 50 year return period frequency is 0.76 m in West River and 0.67 m in North River.③ Except for the upper reaches of the delta, the effect of flood returning to main channel on the rise of flood level in the Pearl River Delta is significantly greater than that of channel deepening. At present, the design water level of the main river course in the delta is mostly 50 year return period. The water level of nearly 900 km reaches exceeds the design water level of the embankment, which is mainly concentrated in the hinterland of the delta near Tianhe, Nanhua and Sanshanjiao.The main conclusions are: ① The return of flood to the channel will cause significant rise of flood level; ② The undercutting of river bed will cause the flood level to decrease generally; ③ Considering the influence of flood return channel and river channel topographic undercutting, flood return channel has basically greater effect on water level rise than river bed undercutting; ④ Under the combined influence of flood channeling and uneven topographic undercutting, abnormal backwater of water level in the abdomen still exists. The rapid contraction of the overflow section along the river and the formation of the bottleneck section are the main reasons for the abnormal backwater of the water level in the abdomen since 1999. The research results can provide basis and technical support for the subsequent overall safety assessment and improvement of the Pearl River Delta flood control system.
2023(3):512-521.
Abstract:
Urban floods have become more and more frequent in a changing environment. Continue climate change and rapid urbanization pose great challenges to traditional stormwater management systems, resulting in frequent flooding in urban areas. Traditional flood control mainly relies on traditional gray infrastructure, because the burden of drainage increases, the method of simply increasing gray infrastructure is not sustainable for stormwater management. As an alternative to traditional gray infrastructure, Green Infrastructure is applied to alleviate urban flood.The sponge system of Daxing Airport is taken as an example. A storm water management model was established to simulate the hydrological process under different combinations of sponge facilities, on the basis of rainfall-runoff data, and the historical rainfall and flood flow data were used for calibration and verification. The different return period of design rainfall (5 a, 10 a, 50 a), according to the current construction situation, three kinds of sponge facilities laid schemes were designed, and compared with the simulation results without any sponge facilities, and the impacts of sponge facilities on flood peak flow, overflow volume were analyzed. The result can provide scientific and technical support for flood control and disaster reduction in the study area.The simulation results indicate: (1) Under different design rainstorm events, Green Infrastructure, landscape lakes, and combined solutions could reduce peak flow and delay peak times of the hydrograph. The rainwater control effect of the combined scheme is the most significant, comparing to the separate solutions. Under the 5-year return period, the reduction rate of the flood peak flow at the outlet and the control rate of the total rainwater amounted to 41.5% and 79.9%, respectively; (2) The storage and stagnation effect of the landscape lake was analyzed under different return periods. The landscape lake accumulates the rainwater during the rainfall under the low return period, reducing the flow of the outlet at the early stage of the rainfall, while the storage space is mainly used for the rainwater confluence in the later period of the rainfall under the high return period. (3) The overflow reduction rate of Green Infrastructure in the upstream area reaches 10.6%, which is obvious in the reduction of flood peaks. The backflow caused by the upstream connection to the landscape lake will lead to an increase in the duration of the backwater. Under the high return period, the backflow rainwater will occupy the water storage space of the open channel, which may increase the overflow risk of the upstream pipe network.Green Infrastructure and landscape lakes have a significant impact on the rainwater control effect in the study area, and the current combination of sponge facilities in the study area can effectively alleviate urban waterloggin. The storage and stagnation effect of the landscape lake is significant for the open channel system, especially for the control of the discharge flow at the outlet; the effect of the Green Infrastructure is reflected in the concentrated construction area, and the adjustment effect is obvious under low rainfall intensity. The Green Infrastructure of the airport and the flood control effect of the landscape lake were initially discussed in order to provide a reference for future research and engineering construction. In future research, the combined dispatch of reservoirs and pumping stations and the combination of sponge facilities can be combined to study the effect of stormwater control under collaborative management.
Urban floods have become more and more frequent in a changing environment. Continue climate change and rapid urbanization pose great challenges to traditional stormwater management systems, resulting in frequent flooding in urban areas. Traditional flood control mainly relies on traditional gray infrastructure, because the burden of drainage increases, the method of simply increasing gray infrastructure is not sustainable for stormwater management. As an alternative to traditional gray infrastructure, Green Infrastructure is applied to alleviate urban flood.The sponge system of Daxing Airport is taken as an example. A storm water management model was established to simulate the hydrological process under different combinations of sponge facilities, on the basis of rainfall-runoff data, and the historical rainfall and flood flow data were used for calibration and verification. The different return period of design rainfall (5 a, 10 a, 50 a), according to the current construction situation, three kinds of sponge facilities laid schemes were designed, and compared with the simulation results without any sponge facilities, and the impacts of sponge facilities on flood peak flow, overflow volume were analyzed. The result can provide scientific and technical support for flood control and disaster reduction in the study area.The simulation results indicate: (1) Under different design rainstorm events, Green Infrastructure, landscape lakes, and combined solutions could reduce peak flow and delay peak times of the hydrograph. The rainwater control effect of the combined scheme is the most significant, comparing to the separate solutions. Under the 5-year return period, the reduction rate of the flood peak flow at the outlet and the control rate of the total rainwater amounted to 41.5% and 79.9%, respectively; (2) The storage and stagnation effect of the landscape lake was analyzed under different return periods. The landscape lake accumulates the rainwater during the rainfall under the low return period, reducing the flow of the outlet at the early stage of the rainfall, while the storage space is mainly used for the rainwater confluence in the later period of the rainfall under the high return period. (3) The overflow reduction rate of Green Infrastructure in the upstream area reaches 10.6%, which is obvious in the reduction of flood peaks. The backflow caused by the upstream connection to the landscape lake will lead to an increase in the duration of the backwater. Under the high return period, the backflow rainwater will occupy the water storage space of the open channel, which may increase the overflow risk of the upstream pipe network.Green Infrastructure and landscape lakes have a significant impact on the rainwater control effect in the study area, and the current combination of sponge facilities in the study area can effectively alleviate urban waterloggin. The storage and stagnation effect of the landscape lake is significant for the open channel system, especially for the control of the discharge flow at the outlet; the effect of the Green Infrastructure is reflected in the concentrated construction area, and the adjustment effect is obvious under low rainfall intensity. The Green Infrastructure of the airport and the flood control effect of the landscape lake were initially discussed in order to provide a reference for future research and engineering construction. In future research, the combined dispatch of reservoirs and pumping stations and the combination of sponge facilities can be combined to study the effect of stormwater control under collaborative management.
2023(3):522-530.
Abstract:
Urban water logging problem becomes more and more prominent under the changing environment. Municipal drainage and river drainage are important systems related to urban water security, and they jointly determine the safety of urban flood control and waterlogging. However, due to several factors such as sample selection method, design storm return period, design rain pattern, and design flow method, it is difficult to connect the urban two-stage drainage system in the design.Hourly rainfall data was selected by the annual maximum method and the annual multiple sample method to construct rainfall structure relationships with predominantly short duration and predominantly long duration. Aiming at the current urban two-stage drainage system standards that can not be connected effectively, the two types of cohesive risks that a two-stage drainage system may encounter were considered in the Grand Airport District of Shenzhen City. The cohesive relation of design storm return period based on municipal short duration and water conservancy long duration were investigated respectively. At the same time, combined with the Chicago rain pattern and the Pearl River Delta rain pattern, the design storm processes of the two-stage drainage system were deduced respectively, and the cohesive relationship between the design of storm peak of urban two-stage drainage system was discussed. The Spearman rank correlation coefficient was used to evaluate the correlation between the connection relationship of each tributary in the Intercepting River basin and the river length, slope, catchment area, and other parameters.In the rainfall structure relationship based on short duration, it was found that the standard articulation of the urban two-stage drainage system showed an increasing trend with increasing rainfall duration, and did not show significant changes with increasing municipal storm return period (0.33~10 a). The articulation of the urban two-stage drainage system is an articulation relationship under the combined effect of the rainfall duration and rainfall intensity. In the rainfall structure relationship dominated by long duration, it was detected that the municipal drainage system was more likely to experience long-duration, small-intensity storms when the water conservancy drainage system was subjected to small return period storms. The municipal drainage system was more likely to experience short-duration, large-intensity storms when the water conservancy drainage system was subjected to large return period storms. The design of stormwater peak articulation of the urban two-stage drainage system revealed that the articulation relationships varied among the tributaries in the Interceptor River basin. Thus, the Spearman rank correlation coefficient analysis revealed a strong correlation between the design stormwater peak articulation relationship and the geographic parameters. Among them, the Spearman correlation coefficients of the articulation relationship with the calculation period, catchment area characteristic parameters, and lag time are 0.82, 0.87, and 0.68 respectively. The results of the above characterizations indicate that the articulation relationship between the return period of water conservancy drainage and municipal drainage is affected by the rainfall intensity and rainfall duration, and also presents a regional heterogeneity. For instance, there are about 2 to 3 times between urban two-stage drainage systems in Tak Fung Wai Chung. That is, when the return period of municipal drainage design is once in X years, the return period of water conservancy drainage design should be designed at least (2 to 3) X years to achieve the connection of an urban two-stage drainage system. Therefore, it is possible to classify the areas in advance and study the relationship between the two-stage drainage system standards by zoning, to obtain a more generalized conclusion.
Urban water logging problem becomes more and more prominent under the changing environment. Municipal drainage and river drainage are important systems related to urban water security, and they jointly determine the safety of urban flood control and waterlogging. However, due to several factors such as sample selection method, design storm return period, design rain pattern, and design flow method, it is difficult to connect the urban two-stage drainage system in the design.Hourly rainfall data was selected by the annual maximum method and the annual multiple sample method to construct rainfall structure relationships with predominantly short duration and predominantly long duration. Aiming at the current urban two-stage drainage system standards that can not be connected effectively, the two types of cohesive risks that a two-stage drainage system may encounter were considered in the Grand Airport District of Shenzhen City. The cohesive relation of design storm return period based on municipal short duration and water conservancy long duration were investigated respectively. At the same time, combined with the Chicago rain pattern and the Pearl River Delta rain pattern, the design storm processes of the two-stage drainage system were deduced respectively, and the cohesive relationship between the design of storm peak of urban two-stage drainage system was discussed. The Spearman rank correlation coefficient was used to evaluate the correlation between the connection relationship of each tributary in the Intercepting River basin and the river length, slope, catchment area, and other parameters.In the rainfall structure relationship based on short duration, it was found that the standard articulation of the urban two-stage drainage system showed an increasing trend with increasing rainfall duration, and did not show significant changes with increasing municipal storm return period (0.33~10 a). The articulation of the urban two-stage drainage system is an articulation relationship under the combined effect of the rainfall duration and rainfall intensity. In the rainfall structure relationship dominated by long duration, it was detected that the municipal drainage system was more likely to experience long-duration, small-intensity storms when the water conservancy drainage system was subjected to small return period storms. The municipal drainage system was more likely to experience short-duration, large-intensity storms when the water conservancy drainage system was subjected to large return period storms. The design of stormwater peak articulation of the urban two-stage drainage system revealed that the articulation relationships varied among the tributaries in the Interceptor River basin. Thus, the Spearman rank correlation coefficient analysis revealed a strong correlation between the design stormwater peak articulation relationship and the geographic parameters. Among them, the Spearman correlation coefficients of the articulation relationship with the calculation period, catchment area characteristic parameters, and lag time are 0.82, 0.87, and 0.68 respectively. The results of the above characterizations indicate that the articulation relationship between the return period of water conservancy drainage and municipal drainage is affected by the rainfall intensity and rainfall duration, and also presents a regional heterogeneity. For instance, there are about 2 to 3 times between urban two-stage drainage systems in Tak Fung Wai Chung. That is, when the return period of municipal drainage design is once in X years, the return period of water conservancy drainage design should be designed at least (2 to 3) X years to achieve the connection of an urban two-stage drainage system. Therefore, it is possible to classify the areas in advance and study the relationship between the two-stage drainage system standards by zoning, to obtain a more generalized conclusion.
2023(3):531-540.
Abstract:
Ejina oasis is located in Alxa Ejina Banner in the western Inner Mongolia Autonomous Region of China. As the first line of ecological defense in north and northwest China, Ejina oasis plays an important role in the economic and social development of north and northwest China, despite its fragile ecological environment. In the latter half of the 20th century, due to the excessive exploitation and utilization of the middle and upper reaches of the Heihe River, the flowing period of the Ejina River was greatly shortened, while the degradation of vegetation and ecosystem of Ejina oasis was accompanied by the severe sandstorms in north China. In order to contain the further ecological deterioration of the lower reaches of Heihe River, the ecological water transfer project was implemented in 2000, since the man-made intermittent water transfer significantly alleviated the ecological deterioration trend of Ejina oasis. Sediment and pollutants flow into the East Juyan Lake along with the runoff, resulting in sedimentation, water quality deterioration and evaporation increasement. Therefore, the analysis of the variation characteristics of streamflow and sediment in the Ejina River is one of the important contents of oasis ecological protection and water distribution management.According to the characteristics of water transport in Ejina oasis, a year is divided into three periods: dry period (no water flow), water transport period (no sand flow) and sediment transport period (sand flow). Based on the daily surface runoff data from 1988 to 2020 and the daily river sediment data from 2006 to 2020 observed at the Donghe and Xihe River sections of Langxin Mountain Hydrological Station, the annual and interannual changes of runoff and sediment in different periods were analyzed by comparative analysis, regression analysis and mathematical statistics. The discharge of Ejina River has obvious seasonal variation, as well the discharge in summer and autumn is significantly higher than that in spring and winter. While the average discharge in spring, summer and winter was still lower than the average level before ecological water transport, the runoff in autumn recovered well and reached nearly 400 million m3 in 2020. The duration of water transport period is characterized by short summer and long winter. Except for summer, the duration of water transport period in all seasons is lengthened. The annual average runoff of Ejina Donghe River is significantly higher than that of Ejina Xihe River, accounting for 72% of the total runoff of Ejina River, which exceeds the statistical data from 2000 to 2015 (70%). After the ecological water transfer in 2000, the runoff volume of Ejina River changed from a sharp downward trend to a significant upward trend. By 2020, the average annual discharge of Ejina Donghe River and Xihe Rivers has reached 16.9 m3 /s and 9.7 m3/s respectively, which is close to the level in the late 1980s. Stage in addition, the water transport period and the sediment transport period of Ejina River are consistent, while the increase of sediment discharge is still affected by the increase of runoff. The maximum sediment concentration generally occurs in July and August when the flow is high, while the sediment discharge in summer and autumn accounts for more than 90% of the whole year. The sudden increase of discharge is a necessary condition for the formation of the strong sediment transport event in the Ejina Donghe and Xihe Rivers, while it is also restricted by the size of discharge and the times of water transport. Generally, only when the peak flow rate increases sharply to more than 100 m3/s for the first time, high sediment concentration (> 5 kg/m3) events will occur, while the sediment content of the river will also decrease with the decrease of the discharge. The relationship between river sediment concentration and river discharge is significant nonlinear. In summer and autumn, the discharge is high, accompanied by strong sediment transport (sediment concentration > 5 kg/m3) and medium sediment transport event (sediment concentration > 1 kg/m3), while the river discharge in spring and winter is small, and most of them are weak sediment transport events(< 1 kg/m3).
Ejina oasis is located in Alxa Ejina Banner in the western Inner Mongolia Autonomous Region of China. As the first line of ecological defense in north and northwest China, Ejina oasis plays an important role in the economic and social development of north and northwest China, despite its fragile ecological environment. In the latter half of the 20th century, due to the excessive exploitation and utilization of the middle and upper reaches of the Heihe River, the flowing period of the Ejina River was greatly shortened, while the degradation of vegetation and ecosystem of Ejina oasis was accompanied by the severe sandstorms in north China. In order to contain the further ecological deterioration of the lower reaches of Heihe River, the ecological water transfer project was implemented in 2000, since the man-made intermittent water transfer significantly alleviated the ecological deterioration trend of Ejina oasis. Sediment and pollutants flow into the East Juyan Lake along with the runoff, resulting in sedimentation, water quality deterioration and evaporation increasement. Therefore, the analysis of the variation characteristics of streamflow and sediment in the Ejina River is one of the important contents of oasis ecological protection and water distribution management.According to the characteristics of water transport in Ejina oasis, a year is divided into three periods: dry period (no water flow), water transport period (no sand flow) and sediment transport period (sand flow). Based on the daily surface runoff data from 1988 to 2020 and the daily river sediment data from 2006 to 2020 observed at the Donghe and Xihe River sections of Langxin Mountain Hydrological Station, the annual and interannual changes of runoff and sediment in different periods were analyzed by comparative analysis, regression analysis and mathematical statistics. The discharge of Ejina River has obvious seasonal variation, as well the discharge in summer and autumn is significantly higher than that in spring and winter. While the average discharge in spring, summer and winter was still lower than the average level before ecological water transport, the runoff in autumn recovered well and reached nearly 400 million m3 in 2020. The duration of water transport period is characterized by short summer and long winter. Except for summer, the duration of water transport period in all seasons is lengthened. The annual average runoff of Ejina Donghe River is significantly higher than that of Ejina Xihe River, accounting for 72% of the total runoff of Ejina River, which exceeds the statistical data from 2000 to 2015 (70%). After the ecological water transfer in 2000, the runoff volume of Ejina River changed from a sharp downward trend to a significant upward trend. By 2020, the average annual discharge of Ejina Donghe River and Xihe Rivers has reached 16.9 m3 /s and 9.7 m3/s respectively, which is close to the level in the late 1980s. Stage in addition, the water transport period and the sediment transport period of Ejina River are consistent, while the increase of sediment discharge is still affected by the increase of runoff. The maximum sediment concentration generally occurs in July and August when the flow is high, while the sediment discharge in summer and autumn accounts for more than 90% of the whole year. The sudden increase of discharge is a necessary condition for the formation of the strong sediment transport event in the Ejina Donghe and Xihe Rivers, while it is also restricted by the size of discharge and the times of water transport. Generally, only when the peak flow rate increases sharply to more than 100 m3/s for the first time, high sediment concentration (> 5 kg/m3) events will occur, while the sediment content of the river will also decrease with the decrease of the discharge. The relationship between river sediment concentration and river discharge is significant nonlinear. In summer and autumn, the discharge is high, accompanied by strong sediment transport (sediment concentration > 5 kg/m3) and medium sediment transport event (sediment concentration > 1 kg/m3), while the river discharge in spring and winter is small, and most of them are weak sediment transport events(< 1 kg/m3).
2023(3):541-549.
Abstract:
Freshwater pond culture had an important position and role in the national economy and even in social development. Baiting was one of the important aspects of the pond culture process, and the rationality of the amount of baiting affected aquatic health and the benign purification of water quality. Traditional pond culture was mostly based on empirical baiting, and its wastewater discharge was prone to eutrophication of farm ponds and water bodies discharged into the waters, which seriously affects the water ecology. The water management of common farm ponds was often characterized by high frequency, fragmentation and arbitrariness, and it was difficult to obtain accurate data on the amount of inflow and outflow by relying entirely on actual measurements.in order to solve the environmental pollution problems caused by traditional pond aquaculture, the water ecological model can be used to simulate the water ecological environment of aquaculture ponds to provide scientific and accurate decision support data. Taking a breeding pond in the Taihu Lake basin as an example, the time series of inflow and outflow was obtained through water balance analysis, and based on this, it was input into the AQUATOX water ecological model for modeling, and conducted control simulations after calibration and verification to explore the mutual influence of baiting rate on water quality and aquaculture products. The phenomenon of excessive feeding in aquaculture pond has a huge impact on the aquatic ecological environment. The results showed that: The total inflow and outflow volumes during the study period were 163 853.11 m3 and 67 635.73 m3; Bait has a large influence on the water quality of the study pond, and the TP, TN and ammonia nitrogen mass concentrations increased significantly overall with the increase of baiting rate in the baiting rate gradient from 1% to 7%; taking the safe mass concentration of cultured products as the watershed, the production of cultured products showed a trend of increasing and then decreasing with the increase of ammonia nitrogen mass concentration in the baiting rate gradient from 1% to 7%.The based rainfall-water level inflow-outflow identification method can fill the measurement gap of specific water management; The water ecosystem model established was simulated well, and the recommended baiting rate in this pond culture was 2.5% to 3% considering the maintenance of good water ecosystem and economic cost.
Freshwater pond culture had an important position and role in the national economy and even in social development. Baiting was one of the important aspects of the pond culture process, and the rationality of the amount of baiting affected aquatic health and the benign purification of water quality. Traditional pond culture was mostly based on empirical baiting, and its wastewater discharge was prone to eutrophication of farm ponds and water bodies discharged into the waters, which seriously affects the water ecology. The water management of common farm ponds was often characterized by high frequency, fragmentation and arbitrariness, and it was difficult to obtain accurate data on the amount of inflow and outflow by relying entirely on actual measurements.in order to solve the environmental pollution problems caused by traditional pond aquaculture, the water ecological model can be used to simulate the water ecological environment of aquaculture ponds to provide scientific and accurate decision support data. Taking a breeding pond in the Taihu Lake basin as an example, the time series of inflow and outflow was obtained through water balance analysis, and based on this, it was input into the AQUATOX water ecological model for modeling, and conducted control simulations after calibration and verification to explore the mutual influence of baiting rate on water quality and aquaculture products. The phenomenon of excessive feeding in aquaculture pond has a huge impact on the aquatic ecological environment. The results showed that: The total inflow and outflow volumes during the study period were 163 853.11 m3 and 67 635.73 m3; Bait has a large influence on the water quality of the study pond, and the TP, TN and ammonia nitrogen mass concentrations increased significantly overall with the increase of baiting rate in the baiting rate gradient from 1% to 7%; taking the safe mass concentration of cultured products as the watershed, the production of cultured products showed a trend of increasing and then decreasing with the increase of ammonia nitrogen mass concentration in the baiting rate gradient from 1% to 7%.The based rainfall-water level inflow-outflow identification method can fill the measurement gap of specific water management; The water ecosystem model established was simulated well, and the recommended baiting rate in this pond culture was 2.5% to 3% considering the maintenance of good water ecosystem and economic cost.
2023(3):550-558.
Abstract:
The measured data of Yanghe Reservoir and Sentinel-2 satellite image data were used to construct an inversion model of total phosphorus mass concentration in the water body, and the temporal and spatial variation characteristics of total phosphorus concentration in Yanghe Reservoir are analyzed, which provided a new way for water quality monitoring of the reservoir, and provided a new method for the reservoir area. Scientific basis was provide for water environment management.Based on the linear regression method, an inversion model between the reflectivity of the remote sensing band and the measured mass concentration of total phosphorus in water was established, and the total phosphorus mass concentration in Yanghe Reservoir from 2016 to 2019 was inverted, and the spatiotemporal characteristics were analyzed.In terms of time distribution, the average concentration of total phosphorus mass concentration in the reservoir in spring and winter is lower than that in summer and autumn, and the water quality in summer and autumn is worse than other seasons. From 2016 to 2018, the water quality of Yanghe Reservoir was relatively good, reaching Class Ⅲ, while the water quality in some months was poor, exceeding Class Ⅲ, mainly in autumn. In 2019, the water quality of Yanghe Reservoir was poor, reaching Class Ⅳ as a whole, and Class Ⅴ in some months, and the excesses were concentrated in summer and autumn. In terms of spatial distribution, the mass concentration of total phosphorus in Yanghe Reservoir in non-flood seasons gradually increased from the east and west entrances and water intakes to the central area of the reservoir. During the flood season, the mass concentration of total phosphorus in the waters near the west entrance was significantly higher than that in other areas. The optimal Sentinel-2 satellite band combination (B3/B5) and the field measured data of the same period were used to establish a total phosphorus mass concentration inversion model. The coefficient of determination (R2) of the established model reaches 0.818, which indicates good applicability. The error analysis between the inversion value and the measured value shows that the average relative error is 19.5%, and the root mean square error is 0.008 67 mg/L, indicating a good model accuracy. However, due to the limitation of geographical conditions, the selected sampling points are few. In the follow-up research, it is necessary to further accumulate the measured data and optimize the regression algorithm. The reason for this phenomenon is that endogenous pollution may be the most important factor in the excess of total phosphorus concentration in Yanghe Reservoir. At the same time, according to the estimation results of pollution sources in the Yanghe Reservoir basin, the total phosphorus non-point source pollution load of the main tributaries on the west side and the Xiyang River accounts for nearly 2/3 of the whole basin. And it is mainly discharged from rural life and livestock and poultry breeding. It also reflects the reason for the higher total phosphorus mass concentration on the west side of the reservoir during the flood season.
The measured data of Yanghe Reservoir and Sentinel-2 satellite image data were used to construct an inversion model of total phosphorus mass concentration in the water body, and the temporal and spatial variation characteristics of total phosphorus concentration in Yanghe Reservoir are analyzed, which provided a new way for water quality monitoring of the reservoir, and provided a new method for the reservoir area. Scientific basis was provide for water environment management.Based on the linear regression method, an inversion model between the reflectivity of the remote sensing band and the measured mass concentration of total phosphorus in water was established, and the total phosphorus mass concentration in Yanghe Reservoir from 2016 to 2019 was inverted, and the spatiotemporal characteristics were analyzed.In terms of time distribution, the average concentration of total phosphorus mass concentration in the reservoir in spring and winter is lower than that in summer and autumn, and the water quality in summer and autumn is worse than other seasons. From 2016 to 2018, the water quality of Yanghe Reservoir was relatively good, reaching Class Ⅲ, while the water quality in some months was poor, exceeding Class Ⅲ, mainly in autumn. In 2019, the water quality of Yanghe Reservoir was poor, reaching Class Ⅳ as a whole, and Class Ⅴ in some months, and the excesses were concentrated in summer and autumn. In terms of spatial distribution, the mass concentration of total phosphorus in Yanghe Reservoir in non-flood seasons gradually increased from the east and west entrances and water intakes to the central area of the reservoir. During the flood season, the mass concentration of total phosphorus in the waters near the west entrance was significantly higher than that in other areas. The optimal Sentinel-2 satellite band combination (B3/B5) and the field measured data of the same period were used to establish a total phosphorus mass concentration inversion model. The coefficient of determination (R2) of the established model reaches 0.818, which indicates good applicability. The error analysis between the inversion value and the measured value shows that the average relative error is 19.5%, and the root mean square error is 0.008 67 mg/L, indicating a good model accuracy. However, due to the limitation of geographical conditions, the selected sampling points are few. In the follow-up research, it is necessary to further accumulate the measured data and optimize the regression algorithm. The reason for this phenomenon is that endogenous pollution may be the most important factor in the excess of total phosphorus concentration in Yanghe Reservoir. At the same time, according to the estimation results of pollution sources in the Yanghe Reservoir basin, the total phosphorus non-point source pollution load of the main tributaries on the west side and the Xiyang River accounts for nearly 2/3 of the whole basin. And it is mainly discharged from rural life and livestock and poultry breeding. It also reflects the reason for the higher total phosphorus mass concentration on the west side of the reservoir during the flood season.
2023(3):559-569.
Abstract:
The water transfer project from the upper reaches of the lower reaches of the Yangtze River to the middle reaches of the Huaihe River is a large-scale inter-basin water transfer project, which is mainly based on urban and rural water supply and the development of Jianghuai shipping, combined with irrigation water replenishment and improvement of Chaohu and Huaihe River water ecological environment. The main stream of the Huaihe River is a storage area for the water transfer project from the Yangtze River to the Huaihe River, and there are many tributaries around it. Once a sudden water pollution incident occurs and improperly handled, it will seriously affect the water supply safety of the main stream and the water transfer section.The joint operation of water quality and quantity is a key measure to deal with sudden water pollution incidents and an important part of improving the water ecology of rivers and lakes. A HEC-RAS one-dimensional hydrodynamic-water quality model of the middle reaches of the Huaihe River was constructed for the event of the Huaihe River pollution group caused by the discharge of sewage from the Shaying River. The emergency response effects of five scheduling methods on the Huaihe River pollution group were analyzed, including increasing the flow of Bengbu sluice, increasing the flow of water transfer from the Yangtze River to the Huaihe River, increasing both at the same time, background scheduling ( no water transfer from the Yangtze River to the Huaihe River ) and conventional scheduling ( water transfer from the Yangtze River to the Huaihe River, but not increasing the flow ).The results show that: for the background scheduling, the peak concentration of the pollution mass is the highest, the exceeding time is the longest, the peak length of the pollution mass is the shortest, and the latest to leave Bengbu gate; for conventional scheduling, the peak concentration of the pollution group is high, and the exceeding time is long. For the optimization of Bengbu gate scheduling, the peak concentration of pollution group is high, the time of exceeding the standard is short, the peak length of pollution group is long, and it leaves Bengbu gate earlier. For the optimal operation of the river transfer, the peak concentration of the pollution mass is the lowest and the exceeding time is longer. For the simultaneous optimization scheduling, the peak concentration of the pollution group is low, the time of exceeding the standard is short, the peak length of the pollution group is the longest, and it leaves Bengbu gate earlier.On the whole, optimizing the Bengbu sluice, optimizing the river transfer and optimizing the disposal effect of the pollution group at the same time are better than the background scheduling and conventional scheduling. Increasing the flow rate of Bengbu sluice will increase the flow rate of the main stream of Huaihe River, thus reducing the residence time of the pollution cluster in front of Bengbu sluice, but it also leads to the increase of the peak length of the pollution cluster. Increase the transfer flow, dilute the concentration of the pollution group, so that the peak concentration of the pollution group becomes lower. At the same time, the optimization not only reduces the residence time of the pollution group in the front of the Bengbu gate, but also reduces the peak concentration of the pollution group, but the peak length of the pollution group becomes longer. From different evaluation indexes of disposal effect, the optimal scheduling measures are different. From the perspective of reducing the peak concentration of the pollution cluster, the optimization of the Yangtze River is optimal; from the perspective of reducing the time of exceeding the standard, optimizing Bengbu gate and optimizing at the same time have significant effects ; from the time of the pollution group leaving the Bengbu gate, it is optimal to increase the discharge of the Bengbu gate. In the actual emergency process of sudden water pollution accident, emergency measures should be selected reasonably and flexibly according to the requirements of evaluation index of disposal effect.
The water transfer project from the upper reaches of the lower reaches of the Yangtze River to the middle reaches of the Huaihe River is a large-scale inter-basin water transfer project, which is mainly based on urban and rural water supply and the development of Jianghuai shipping, combined with irrigation water replenishment and improvement of Chaohu and Huaihe River water ecological environment. The main stream of the Huaihe River is a storage area for the water transfer project from the Yangtze River to the Huaihe River, and there are many tributaries around it. Once a sudden water pollution incident occurs and improperly handled, it will seriously affect the water supply safety of the main stream and the water transfer section.The joint operation of water quality and quantity is a key measure to deal with sudden water pollution incidents and an important part of improving the water ecology of rivers and lakes. A HEC-RAS one-dimensional hydrodynamic-water quality model of the middle reaches of the Huaihe River was constructed for the event of the Huaihe River pollution group caused by the discharge of sewage from the Shaying River. The emergency response effects of five scheduling methods on the Huaihe River pollution group were analyzed, including increasing the flow of Bengbu sluice, increasing the flow of water transfer from the Yangtze River to the Huaihe River, increasing both at the same time, background scheduling ( no water transfer from the Yangtze River to the Huaihe River ) and conventional scheduling ( water transfer from the Yangtze River to the Huaihe River, but not increasing the flow ).The results show that: for the background scheduling, the peak concentration of the pollution mass is the highest, the exceeding time is the longest, the peak length of the pollution mass is the shortest, and the latest to leave Bengbu gate; for conventional scheduling, the peak concentration of the pollution group is high, and the exceeding time is long. For the optimization of Bengbu gate scheduling, the peak concentration of pollution group is high, the time of exceeding the standard is short, the peak length of pollution group is long, and it leaves Bengbu gate earlier. For the optimal operation of the river transfer, the peak concentration of the pollution mass is the lowest and the exceeding time is longer. For the simultaneous optimization scheduling, the peak concentration of the pollution group is low, the time of exceeding the standard is short, the peak length of the pollution group is the longest, and it leaves Bengbu gate earlier.On the whole, optimizing the Bengbu sluice, optimizing the river transfer and optimizing the disposal effect of the pollution group at the same time are better than the background scheduling and conventional scheduling. Increasing the flow rate of Bengbu sluice will increase the flow rate of the main stream of Huaihe River, thus reducing the residence time of the pollution cluster in front of Bengbu sluice, but it also leads to the increase of the peak length of the pollution cluster. Increase the transfer flow, dilute the concentration of the pollution group, so that the peak concentration of the pollution group becomes lower. At the same time, the optimization not only reduces the residence time of the pollution group in the front of the Bengbu gate, but also reduces the peak concentration of the pollution group, but the peak length of the pollution group becomes longer. From different evaluation indexes of disposal effect, the optimal scheduling measures are different. From the perspective of reducing the peak concentration of the pollution cluster, the optimization of the Yangtze River is optimal; from the perspective of reducing the time of exceeding the standard, optimizing Bengbu gate and optimizing at the same time have significant effects ; from the time of the pollution group leaving the Bengbu gate, it is optimal to increase the discharge of the Bengbu gate. In the actual emergency process of sudden water pollution accident, emergency measures should be selected reasonably and flexibly according to the requirements of evaluation index of disposal effect.
2023(3):570-580.
Abstract:
With the rapid development of society and excessive utilization , river ecosystem has been deteriorated seriously, charaterizing by decreasing water resources, water pollution, decling biodiversity and shrinking wetlands, etc, which limit the sustainable development of social economy and the further improvement of people's quality of life. Assessment of river health is the foundation of ecosystem monitoring and protection, and has been paid great attention in China. Most researches of river health was a comprehensive assessment consisting of hydrology, water quality, river habitat, organism and so on, which assumed as a stationary river system. Fewer researches regard river vulnerability as an important part of river health assessment. Under the dual pressures from climate change and human activities, the ability of watersheds to recover from external disturbances is particularly important, and should be considered in the river health assessment. Located in the central part of the Shandong Province, the Xiaoqing River is an important area of politics, economy, technology and culture in this province, and plays a pivotal role in the development of the society and economy. Assessing the health status of the Xiaoqing River under the changing environment is essential for the sustainable development, especially since the resumption of navigation.A total of eight sites, located in the main stream of the Xiaoqing River, were evaluated in this paper. The river health assessment system of the main stream of the Xiaoqing River was constructed including 17 indices from 6 criterion layers to assess the health status, including water quantity, water quality, organisms, aquatic ecology, social services and watershed vulnerability. Four components, namely, precipitation change, climate changes, water use changes and the impervious area changes, were used to evaluate the watershed vulnerability caused by climate change and human disturbance. Monthly flow was obtained from 《HYDROLOGICAL DATA OF HUAIHE RIVER BASIN》, precipitation, temperature and land use data were downloaded from Resource and Environment Science and Data Center of Chinese academy of science, other data such as water quality were obtained by sampling in situ. Five indices were consisted in the vulnerability criterion layer, and the temperature and precipitation in 2030 were predicted by Weather generators, the area of impervious area in 2030 was by PLUS model, and the water use in 2030 was by traditional model plates in SPSS. The Analytic Hierarchy Process was applied to calculate the weight of the indicators, which the water quantity and water quality were conferred the heaviest value. Finally, the river health index of each site were calculated by the weight and the assigned value, and the river health level was divided into five levels, showing as very healthy state, healthy state, sub-healthy state, unhealthy state, inferior state.The results show that the weight of the indices ranged from 0.014 to 0.161, among which the weight of ecological flow and water purification were the largest, and the weight of the vulnerability of future temperature change in the future was the smallest. The main stream of Xiaoqing River is in sub-healthy state, and the river health index at 8 evaluation sites was distributed between 61.82 and 69.73. There was little difference among each site in the main stream, of which Huangtaiqiao is the highest and the Chahe site was the lowest. The water quantity scored the highest in the criterion layer. Poor aquatic biology and higher vulnerability facing the changing environment were the main limitation factors in the Xiaoqing River, and leading to unreliable health in the future. Besides, the river habitats layer and water quality layer scored ranked third and fourth, respectively. Spatial variation in this river showed a trend of lower scores from upstream to downstream. The ecological flow satisfaction scored the highest in the indicator layer, with a score of 100 for all 8 sites, and a score of 0 for the indicators of the changes in minimum temperature and future water use change. Stability of the riverbank and the changes of impervious area got higher score than other indicators. The vulnerability layer showed that the changes of temperature in next 10 years should be noted and measurements of alleviating the increase of temperature shoule be carried out. Water use scored 0, which may increase the intense of water in the future, and the policy of water conservation must be taken. River restoration work should be carried out in accordance with local conditions in response to the vulnerability factors in different river sections.The index system of the main stream in the Xiaoqing River can evaluate the health status comprehensively from 6 aspects, including water quantity, water quality, water aquatic species, water ecology, social services and vulnerability. Generally speaking, the above results showed that more efforts should be made to protect and restore the basin and prevent it from deterioration. In the future,we should not only strengthen the monitoring and governance of indices with low scores but also stabilize indicators with high scores to maintain the high health level. The construction of the evaluation index system in the Xiaoqing River provides a reference for scientific management, and may provide a theoretical support for the future ecological restoration and high-level development.
With the rapid development of society and excessive utilization , river ecosystem has been deteriorated seriously, charaterizing by decreasing water resources, water pollution, decling biodiversity and shrinking wetlands, etc, which limit the sustainable development of social economy and the further improvement of people's quality of life. Assessment of river health is the foundation of ecosystem monitoring and protection, and has been paid great attention in China. Most researches of river health was a comprehensive assessment consisting of hydrology, water quality, river habitat, organism and so on, which assumed as a stationary river system. Fewer researches regard river vulnerability as an important part of river health assessment. Under the dual pressures from climate change and human activities, the ability of watersheds to recover from external disturbances is particularly important, and should be considered in the river health assessment. Located in the central part of the Shandong Province, the Xiaoqing River is an important area of politics, economy, technology and culture in this province, and plays a pivotal role in the development of the society and economy. Assessing the health status of the Xiaoqing River under the changing environment is essential for the sustainable development, especially since the resumption of navigation.A total of eight sites, located in the main stream of the Xiaoqing River, were evaluated in this paper. The river health assessment system of the main stream of the Xiaoqing River was constructed including 17 indices from 6 criterion layers to assess the health status, including water quantity, water quality, organisms, aquatic ecology, social services and watershed vulnerability. Four components, namely, precipitation change, climate changes, water use changes and the impervious area changes, were used to evaluate the watershed vulnerability caused by climate change and human disturbance. Monthly flow was obtained from 《HYDROLOGICAL DATA OF HUAIHE RIVER BASIN》, precipitation, temperature and land use data were downloaded from Resource and Environment Science and Data Center of Chinese academy of science, other data such as water quality were obtained by sampling in situ. Five indices were consisted in the vulnerability criterion layer, and the temperature and precipitation in 2030 were predicted by Weather generators, the area of impervious area in 2030 was by PLUS model, and the water use in 2030 was by traditional model plates in SPSS. The Analytic Hierarchy Process was applied to calculate the weight of the indicators, which the water quantity and water quality were conferred the heaviest value. Finally, the river health index of each site were calculated by the weight and the assigned value, and the river health level was divided into five levels, showing as very healthy state, healthy state, sub-healthy state, unhealthy state, inferior state.The results show that the weight of the indices ranged from 0.014 to 0.161, among which the weight of ecological flow and water purification were the largest, and the weight of the vulnerability of future temperature change in the future was the smallest. The main stream of Xiaoqing River is in sub-healthy state, and the river health index at 8 evaluation sites was distributed between 61.82 and 69.73. There was little difference among each site in the main stream, of which Huangtaiqiao is the highest and the Chahe site was the lowest. The water quantity scored the highest in the criterion layer. Poor aquatic biology and higher vulnerability facing the changing environment were the main limitation factors in the Xiaoqing River, and leading to unreliable health in the future. Besides, the river habitats layer and water quality layer scored ranked third and fourth, respectively. Spatial variation in this river showed a trend of lower scores from upstream to downstream. The ecological flow satisfaction scored the highest in the indicator layer, with a score of 100 for all 8 sites, and a score of 0 for the indicators of the changes in minimum temperature and future water use change. Stability of the riverbank and the changes of impervious area got higher score than other indicators. The vulnerability layer showed that the changes of temperature in next 10 years should be noted and measurements of alleviating the increase of temperature shoule be carried out. Water use scored 0, which may increase the intense of water in the future, and the policy of water conservation must be taken. River restoration work should be carried out in accordance with local conditions in response to the vulnerability factors in different river sections.The index system of the main stream in the Xiaoqing River can evaluate the health status comprehensively from 6 aspects, including water quantity, water quality, water aquatic species, water ecology, social services and vulnerability. Generally speaking, the above results showed that more efforts should be made to protect and restore the basin and prevent it from deterioration. In the future,we should not only strengthen the monitoring and governance of indices with low scores but also stabilize indicators with high scores to maintain the high health level. The construction of the evaluation index system in the Xiaoqing River provides a reference for scientific management, and may provide a theoretical support for the future ecological restoration and high-level development.
2023(3):581-588.
Abstract:
The drift ice is easy accumulate and form to ice dam which will block the river channel and reduce the river's water carrying capacity during freezing and melting period. Once the ice dam is formed, the rapid rise of water level in the short term will lead to ice flood danger. Ice flood disasters seriously affect the safety of the waterway, the stability of hydraulic structures, the ecological balance of the river, etc. According to statistical analysis, a relatively serious ice dam formed in the upper reaches of Heilongjiang River every three years and the location was not fixed. Meanwhile, it is very difficult to understand and predict the occurrence and severity of ice dam because of the chaotic nature of ice dam formation and its impact on river hydraulic conditions. In view of this, it is hoped to provide support for the prediction of ice dam in Heilongjiang River by studying the velocity variation of drift ice in the upper reaches of Heilongjiang River during ice break-up season.In the past, more studies were conducted on the process of river ice creation and removal, river opening forecasting, and ice damage risk assessment which with prototype observation, numerical simulation and theoretical models serving as the predominant research approaches. The quantitative monitoring of drift ice movement is highly challenging, and the early research on ice movement and velocity are often watched visually by employees. With the development of technology, the drift ice velocity values of river sections can be obtained by relying on acoustic Doppler radar, particle image velocimetry, image measurement techniques and satellite remote sensing technology. The progress of technology supports the accurate measurement of the ice velocity and transmission process along the river, which is lays a solid foundation for the assessment of river ice dynamics and ice flood prediction.The application of GPS positioning technology in the measurement of glacier movement speed and sea ice drift speed was quite mature. Using this method, the drift ice tracking test was conducted by the micro buoy locator to investigate the changing pattern of drift ice velocity along the river channel and transport process in the upper reaches of Heilongjiang River during ice break-up season. The plane positioning accuracy of the micro buoy locator was less than 10 m that used the positioning mode of "BDS+GPS+BTS" and returned the time, longitude, latitude, speed and speed direction information at an interval of 10 s. Then, the drift ice velocity can be accurately calculated through the position information of two adjacent time nodes of the mini-buoy locator.The results show that the velocity of drift ice ranged from 0.79 m/s to 3.56 m/s, and the mean velocity is about 1.65 m/s in the upper reaches of Heilongjiang River during ice break-up season. In addition, there is a negative correlation between the velocity of drift ice with the river width, and the specific performance was that the velocity of drift ice increases at the narrow part of the river channel and decreases at the wide part of the river channel. Furthermore, the velocity of drift ice decreases near the entrance and exit of the bend which verified by the first bay reach of Heilongjiang River, because it is easy to form spiral flow movement under the action of centrifugal force when the drift ice flows through the bend. On this basis, the application prospect of micro buoy locator in Heilongjiang River ice flood prevention is prospected.
The drift ice is easy accumulate and form to ice dam which will block the river channel and reduce the river's water carrying capacity during freezing and melting period. Once the ice dam is formed, the rapid rise of water level in the short term will lead to ice flood danger. Ice flood disasters seriously affect the safety of the waterway, the stability of hydraulic structures, the ecological balance of the river, etc. According to statistical analysis, a relatively serious ice dam formed in the upper reaches of Heilongjiang River every three years and the location was not fixed. Meanwhile, it is very difficult to understand and predict the occurrence and severity of ice dam because of the chaotic nature of ice dam formation and its impact on river hydraulic conditions. In view of this, it is hoped to provide support for the prediction of ice dam in Heilongjiang River by studying the velocity variation of drift ice in the upper reaches of Heilongjiang River during ice break-up season.In the past, more studies were conducted on the process of river ice creation and removal, river opening forecasting, and ice damage risk assessment which with prototype observation, numerical simulation and theoretical models serving as the predominant research approaches. The quantitative monitoring of drift ice movement is highly challenging, and the early research on ice movement and velocity are often watched visually by employees. With the development of technology, the drift ice velocity values of river sections can be obtained by relying on acoustic Doppler radar, particle image velocimetry, image measurement techniques and satellite remote sensing technology. The progress of technology supports the accurate measurement of the ice velocity and transmission process along the river, which is lays a solid foundation for the assessment of river ice dynamics and ice flood prediction.The application of GPS positioning technology in the measurement of glacier movement speed and sea ice drift speed was quite mature. Using this method, the drift ice tracking test was conducted by the micro buoy locator to investigate the changing pattern of drift ice velocity along the river channel and transport process in the upper reaches of Heilongjiang River during ice break-up season. The plane positioning accuracy of the micro buoy locator was less than 10 m that used the positioning mode of "BDS+GPS+BTS" and returned the time, longitude, latitude, speed and speed direction information at an interval of 10 s. Then, the drift ice velocity can be accurately calculated through the position information of two adjacent time nodes of the mini-buoy locator.The results show that the velocity of drift ice ranged from 0.79 m/s to 3.56 m/s, and the mean velocity is about 1.65 m/s in the upper reaches of Heilongjiang River during ice break-up season. In addition, there is a negative correlation between the velocity of drift ice with the river width, and the specific performance was that the velocity of drift ice increases at the narrow part of the river channel and decreases at the wide part of the river channel. Furthermore, the velocity of drift ice decreases near the entrance and exit of the bend which verified by the first bay reach of Heilongjiang River, because it is easy to form spiral flow movement under the action of centrifugal force when the drift ice flows through the bend. On this basis, the application prospect of micro buoy locator in Heilongjiang River ice flood prevention is prospected.
18 Analysis of internal flow and hydraulic performance of bidirectional submersible
tubular pump device
2023(3):589-596.
Abstract:
Bidirectional submersible tubular pump device is a kind of mechatronics product combining diving motor and tubular pump technology, which has the advantages of high efficiency of tubular pump device and overcomes the technology problem of cooling, heat dissipation and sealing of traditional pump motor. It is more and more applied in the water conservancy project which combines urban water-logging drainage and water environment improvement.In order to clarify the inflow characteristics and hydraulic performance of the bidirectional submersible tubular pump device, bidirectional submersible tubular pump device in Yangzhou gate pumping station was taken as the research object. Based on SST C-C turbulence model, CFD software was used for numerical calculation of flow field of the full flow channel of bidirectional submersible tubular pump device. And the effectiveness of the numerical calculation was verified by the model test. It was found that, if the the pumping station is dominated by water-logging drainage and supplemented by water diversion, the best calculation scheme of pump device is to put the bulb in front in water-logging drainage condition and put the bulb rearward in water diversion condition. Based on the calculation scheme, the maximum efficiency was 58.41% when the bidirectional submersible tubular pump device was in reverse operation and the maximum efficiency was 59.29% in forward operation at the blade angle of 0° and at the blade adjustment angle of bilateral adjustable guide vanes of 0°. In the forward and reverse operation, the flow-head curve and flow-efficiency curve of the pump device predicted by numerical simulation and model test have the same trend, and the absolute difference of efficiency is within 5%. The high efficiency condition Q=303 L/s in forward operation and Q=237 L/s in reverse operation were selected for analysis: in forward operation, the streamlines in the inlet side of straight tube flow channel, diffusion guide vane and bulb were smooth, the flow pattern was good, and no vortex and other bad flow patterns were observed. While the streamlines in the outlet area of straight guide vane were disordered and flow patterns in the inlet area of outlet side of straight tube flow channel. In reverse operation, the streamlines in the inlet side of straight tube flow channel and inside of straight guide vane were smooth, while vortex cavity were apparently observed in the support of diffusion guide vane. The streamlines at the tail of bulb were also disordered and the flow patterns in the mid-front area of outlet side of straight tube flow channel were disordered; When the flow ranged in 220 to 350 L/s in forward operation, the mean value of axial velocity distribution uniformity in the outlet surface of straight tube flow channel was 92.92% and extreme difference was 2.24%. The mean value of velocity weighted average angle in the outlet surface of straight tube flow channel was 89.81° and extreme difference of each calculation condition was only 0.08%. When the flow ranged in 180 to 280 L/s in reverse operation, the mean value of axial velocity distribution uniformity in the outlet surface of straight tube flow channel was 93.92% and extreme difference was 1.1%. The mean value of velocity weighted average angle in the outlet surface of straight tube flow channel was 89.84° and extreme difference of each calculation condition was only 0.1%; In high efficiency condition, the area of the deviation angle of the water flow from the outlet surface of the straight guide vane to the inlet surface of the outlet conduit was gradually increased in the range of ?0.3° to 0.3° ; The axial force of the two-way impeller of the pump device decreased with the increase of the flow , and the change trend was consistent.Conclusions: (1) when the blade angle was 0°, the blade adjustment angle of bilateral adjustable guide vanes was 0° and the bulb was located on the outer river side, the maximum efficiency of the pump device was 59.29% in the water-logging drainage condition and 58.41% in the water diversion condition. (2) In different flow conditions, the impeller inlet side of the flow structure internal streamlines were smooth, and flow pattern were good; the impeller outlet side of the flow structure internal flow pattern was relatively disordered. In the two-way operation, The pressure on the pressure surface of the blade was uniform, and the flow analysis phenomenon was observed at the inlet edge of the suction surface of the blade. (3) In the two-way operation, the outlet surface of the straight tube inlet flow channel axial velocity distribution uniformity was greater than 92%, the average weighted velocity angle was greater than 89°, the straight tube inlet flow channel provided a good inflow velocity distribution for the impeller. In high efficiency condition, the deflection angle at the inlet of the outlet conduit of the pump device was lower than that at the outlet of the guide vane. The axial force on the impeller decreased with the increase of flow. The research results provided certain reference values for the structural optimization and efficient and safe operation of bidirectional submersible tubular pump device.
Bidirectional submersible tubular pump device is a kind of mechatronics product combining diving motor and tubular pump technology, which has the advantages of high efficiency of tubular pump device and overcomes the technology problem of cooling, heat dissipation and sealing of traditional pump motor. It is more and more applied in the water conservancy project which combines urban water-logging drainage and water environment improvement.In order to clarify the inflow characteristics and hydraulic performance of the bidirectional submersible tubular pump device, bidirectional submersible tubular pump device in Yangzhou gate pumping station was taken as the research object. Based on SST C-C turbulence model, CFD software was used for numerical calculation of flow field of the full flow channel of bidirectional submersible tubular pump device. And the effectiveness of the numerical calculation was verified by the model test. It was found that, if the the pumping station is dominated by water-logging drainage and supplemented by water diversion, the best calculation scheme of pump device is to put the bulb in front in water-logging drainage condition and put the bulb rearward in water diversion condition. Based on the calculation scheme, the maximum efficiency was 58.41% when the bidirectional submersible tubular pump device was in reverse operation and the maximum efficiency was 59.29% in forward operation at the blade angle of 0° and at the blade adjustment angle of bilateral adjustable guide vanes of 0°. In the forward and reverse operation, the flow-head curve and flow-efficiency curve of the pump device predicted by numerical simulation and model test have the same trend, and the absolute difference of efficiency is within 5%. The high efficiency condition Q=303 L/s in forward operation and Q=237 L/s in reverse operation were selected for analysis: in forward operation, the streamlines in the inlet side of straight tube flow channel, diffusion guide vane and bulb were smooth, the flow pattern was good, and no vortex and other bad flow patterns were observed. While the streamlines in the outlet area of straight guide vane were disordered and flow patterns in the inlet area of outlet side of straight tube flow channel. In reverse operation, the streamlines in the inlet side of straight tube flow channel and inside of straight guide vane were smooth, while vortex cavity were apparently observed in the support of diffusion guide vane. The streamlines at the tail of bulb were also disordered and the flow patterns in the mid-front area of outlet side of straight tube flow channel were disordered; When the flow ranged in 220 to 350 L/s in forward operation, the mean value of axial velocity distribution uniformity in the outlet surface of straight tube flow channel was 92.92% and extreme difference was 2.24%. The mean value of velocity weighted average angle in the outlet surface of straight tube flow channel was 89.81° and extreme difference of each calculation condition was only 0.08%. When the flow ranged in 180 to 280 L/s in reverse operation, the mean value of axial velocity distribution uniformity in the outlet surface of straight tube flow channel was 93.92% and extreme difference was 1.1%. The mean value of velocity weighted average angle in the outlet surface of straight tube flow channel was 89.84° and extreme difference of each calculation condition was only 0.1%; In high efficiency condition, the area of the deviation angle of the water flow from the outlet surface of the straight guide vane to the inlet surface of the outlet conduit was gradually increased in the range of ?0.3° to 0.3° ; The axial force of the two-way impeller of the pump device decreased with the increase of the flow , and the change trend was consistent.Conclusions: (1) when the blade angle was 0°, the blade adjustment angle of bilateral adjustable guide vanes was 0° and the bulb was located on the outer river side, the maximum efficiency of the pump device was 59.29% in the water-logging drainage condition and 58.41% in the water diversion condition. (2) In different flow conditions, the impeller inlet side of the flow structure internal streamlines were smooth, and flow pattern were good; the impeller outlet side of the flow structure internal flow pattern was relatively disordered. In the two-way operation, The pressure on the pressure surface of the blade was uniform, and the flow analysis phenomenon was observed at the inlet edge of the suction surface of the blade. (3) In the two-way operation, the outlet surface of the straight tube inlet flow channel axial velocity distribution uniformity was greater than 92%, the average weighted velocity angle was greater than 89°, the straight tube inlet flow channel provided a good inflow velocity distribution for the impeller. In high efficiency condition, the deflection angle at the inlet of the outlet conduit of the pump device was lower than that at the outlet of the guide vane. The axial force on the impeller decreased with the increase of flow. The research results provided certain reference values for the structural optimization and efficient and safe operation of bidirectional submersible tubular pump device.
2023(3):597-607.
Abstract:
Water, energy and food are the most essential basic resources to promote social progress and there is a compact and complex nexus between them. With the continuous growth of global population, the contradiction between supply and demand of water, energy and food is becoming increasingly prominent, which makes the development of fundamental industries bound up with these three resources become an overall and strategic issue related to the economic and social development of the country as well as the improvement of people's living standards. Yangtze River Economic Belt is a notable inland river economic belt with the longest depth and the broadest coverage in China and plays a significant role as an engine in China's economic development. Currently, there are many challenges ahead to the development of water, energy and food industries in this area, hence it is particularly important to study the relationship among the three industries and their impact on social and economic development in order to promote industrial transformation and upgrade industrial integration and coordinated development of the area.The water-energy-food industry in the Yangtze River Economic Belt was focused on based on the input-output data of the economic belt in 2002, 2007, 2012 and 2017. On this basis, three types of resources were linked with industries and the water-energy-food input-output model of the Yangtze River Economic Belt was constructed to describe the input sources and output usage directions of raw materials produced, and the input-output coefficient, industrial system structure characteristics, correlation between industries and their change trends of three industries in different development stages were analyzed and the evolution of the correlation and ripple effect of water-energy-food industries were further analyzed.The results showed that there were obvious differences between three industries from the perspective of correlation and ripple effect: the water product and supply industry was increasingly related to itself in both forward and backward direction, and was most closely related to the energy industry. The forward correlation to the whole water-energy-food industrial system increased, while the backward correlation weakened, and the demand structure tended to weaken the driving effect on the regional economy, but in recent years, its level of sensitivity to social economy has significantly improved. The energy industry played a strong role in promoting and restricting the water-energy-food industrial system and was vulnerable to the impact of economic fluctuations and consumption from other industries. When the economy develops at a high speed, the energy industry will face greater pressure from social demand. The energy industry was also a correlation-sensitive industry. Meanwhile, it was an intermediate product industry with low added value and high driving force, but lacked the momentum for sustainable development. The food industry had a weak direct connection with other industries. The overall development state was relatively stable, and it did not exert prominent driving force and pulling force on the water-energy-food industrial system and the whole social economy. It belonged to the intermediate product basic industry with slack correlation, the development status of food industry was independent and steady.Based on the above analysis, relevant policies need to be formulated to strengthen related work such as water conservation in energy and food industry, and expand the upstream industry output and downstream industry transaction scale of the water production and supply industry to improve their investment rate. For the energy industry, it is necessary to focus on internal optimization and independent innovation. The food industry needs to focus on cultivating its internal development momentum, increasing capital and technological inputs, and reducing production cost inputs. At the same time, Yangtze River Economic Belt needs to comprehensively consider the situation of three industries, promote the integrated development of the water-energy-food industry, focus on the integration of upstream and downstream resources in the industrial chain, and accelerate the integration of industries.
Water, energy and food are the most essential basic resources to promote social progress and there is a compact and complex nexus between them. With the continuous growth of global population, the contradiction between supply and demand of water, energy and food is becoming increasingly prominent, which makes the development of fundamental industries bound up with these three resources become an overall and strategic issue related to the economic and social development of the country as well as the improvement of people's living standards. Yangtze River Economic Belt is a notable inland river economic belt with the longest depth and the broadest coverage in China and plays a significant role as an engine in China's economic development. Currently, there are many challenges ahead to the development of water, energy and food industries in this area, hence it is particularly important to study the relationship among the three industries and their impact on social and economic development in order to promote industrial transformation and upgrade industrial integration and coordinated development of the area.The water-energy-food industry in the Yangtze River Economic Belt was focused on based on the input-output data of the economic belt in 2002, 2007, 2012 and 2017. On this basis, three types of resources were linked with industries and the water-energy-food input-output model of the Yangtze River Economic Belt was constructed to describe the input sources and output usage directions of raw materials produced, and the input-output coefficient, industrial system structure characteristics, correlation between industries and their change trends of three industries in different development stages were analyzed and the evolution of the correlation and ripple effect of water-energy-food industries were further analyzed.The results showed that there were obvious differences between three industries from the perspective of correlation and ripple effect: the water product and supply industry was increasingly related to itself in both forward and backward direction, and was most closely related to the energy industry. The forward correlation to the whole water-energy-food industrial system increased, while the backward correlation weakened, and the demand structure tended to weaken the driving effect on the regional economy, but in recent years, its level of sensitivity to social economy has significantly improved. The energy industry played a strong role in promoting and restricting the water-energy-food industrial system and was vulnerable to the impact of economic fluctuations and consumption from other industries. When the economy develops at a high speed, the energy industry will face greater pressure from social demand. The energy industry was also a correlation-sensitive industry. Meanwhile, it was an intermediate product industry with low added value and high driving force, but lacked the momentum for sustainable development. The food industry had a weak direct connection with other industries. The overall development state was relatively stable, and it did not exert prominent driving force and pulling force on the water-energy-food industrial system and the whole social economy. It belonged to the intermediate product basic industry with slack correlation, the development status of food industry was independent and steady.Based on the above analysis, relevant policies need to be formulated to strengthen related work such as water conservation in energy and food industry, and expand the upstream industry output and downstream industry transaction scale of the water production and supply industry to improve their investment rate. For the energy industry, it is necessary to focus on internal optimization and independent innovation. The food industry needs to focus on cultivating its internal development momentum, increasing capital and technological inputs, and reducing production cost inputs. At the same time, Yangtze River Economic Belt needs to comprehensively consider the situation of three industries, promote the integrated development of the water-energy-food industry, focus on the integration of upstream and downstream resources in the industrial chain, and accelerate the integration of industries.
2023(3):608-616.
Abstract:
Water conservation is the key measure to solve the complex water problem in China, which is widely paid attention by the whole society. Literature is an important carrier to record research jobs and practical achievements in different fields, which can reflect the key points, hot issues, and difficult problems of a certain research field in a certain period. Systematic review and analysis of water conservation-related literature are helpful to understand the main direction and key content of water conservation research in different periods.Literature on water conservation research was retrieved from the Chinese Academic Journal Database of China national knowledge Internet from 1949 to 2021, and water conservation policy documents related to the same period were counted. The annual publication of literature and the number of policy documents issued over the years were analyzed. High frequency keywords and burst terms were obtained by key words clustering and burst detection of CiteSpace. Based on this, the core content and frontier of water conservation research were analyzed. Typical water conservation policy documents and high frequency key words and burst terms in the same period were counted to analyze the impact of policy documents on the content of water conservation research. Using the key words clustering and key words timeline visualization, the research themes of water conservation and the change of content in each theme with time were obtained.The results show that: (1) The number of published scientific research was affected by the promulgation of policy documents. Major policies played a significant role in guiding scientific research work. (2) Agriculture is the key field of water conservation research. Water conservation research focused on irrigation technology in the early stage. With the expansion of research fields and the increase of research objects, the comprehensive application of water conservation technology was the current research hotspot. (3) Water conservation research formed a research structure with water resource management as the core, high efficient water conservation as the main goal, and irrigation technology, water conservation irrigation, and water conservation agriculture as technical means. (4) 1982, 2002, and 2012 were the important time nodes in the promulgation of water conservation policy and the process of water conservation research. According to these time nodes, the development history of water conservation can be divided into four stages: the embryonic stage (1949-1981), the preliminary stage (1982-2001), the overall development stage (2002-2011), the deepening stage (2012 to date).In the embryonic stage of water conservation, the number of literature on water conservation was few, and practical work mainly focused on agricultural water conservation which was in the experimental stage. In the stage of preliminary, the problem of water shortage gradually emerged, water conservation research began to be active, and efforts to conserve water in agriculture, cities, and daily life continued to advance. In the overall development stage, water conservation was becoming more urgent as water consumption continued to increase. Research on new technologies and methods to conserve water kept emerging, and water conservation involved more and more research fields. In the stage of deepening water conservation, the research field of water conservation was further broadened and deepened, and the content of water conservation research became more abundant and more diversified. The comprehensive application of engineering technology means and management means was valued. These advances promoted the development of water conservation work forward.
Water conservation is the key measure to solve the complex water problem in China, which is widely paid attention by the whole society. Literature is an important carrier to record research jobs and practical achievements in different fields, which can reflect the key points, hot issues, and difficult problems of a certain research field in a certain period. Systematic review and analysis of water conservation-related literature are helpful to understand the main direction and key content of water conservation research in different periods.Literature on water conservation research was retrieved from the Chinese Academic Journal Database of China national knowledge Internet from 1949 to 2021, and water conservation policy documents related to the same period were counted. The annual publication of literature and the number of policy documents issued over the years were analyzed. High frequency keywords and burst terms were obtained by key words clustering and burst detection of CiteSpace. Based on this, the core content and frontier of water conservation research were analyzed. Typical water conservation policy documents and high frequency key words and burst terms in the same period were counted to analyze the impact of policy documents on the content of water conservation research. Using the key words clustering and key words timeline visualization, the research themes of water conservation and the change of content in each theme with time were obtained.The results show that: (1) The number of published scientific research was affected by the promulgation of policy documents. Major policies played a significant role in guiding scientific research work. (2) Agriculture is the key field of water conservation research. Water conservation research focused on irrigation technology in the early stage. With the expansion of research fields and the increase of research objects, the comprehensive application of water conservation technology was the current research hotspot. (3) Water conservation research formed a research structure with water resource management as the core, high efficient water conservation as the main goal, and irrigation technology, water conservation irrigation, and water conservation agriculture as technical means. (4) 1982, 2002, and 2012 were the important time nodes in the promulgation of water conservation policy and the process of water conservation research. According to these time nodes, the development history of water conservation can be divided into four stages: the embryonic stage (1949-1981), the preliminary stage (1982-2001), the overall development stage (2002-2011), the deepening stage (2012 to date).In the embryonic stage of water conservation, the number of literature on water conservation was few, and practical work mainly focused on agricultural water conservation which was in the experimental stage. In the stage of preliminary, the problem of water shortage gradually emerged, water conservation research began to be active, and efforts to conserve water in agriculture, cities, and daily life continued to advance. In the overall development stage, water conservation was becoming more urgent as water consumption continued to increase. Research on new technologies and methods to conserve water kept emerging, and water conservation involved more and more research fields. In the stage of deepening water conservation, the research field of water conservation was further broadened and deepened, and the content of water conservation research became more abundant and more diversified. The comprehensive application of engineering technology means and management means was valued. These advances promoted the development of water conservation work forward.
2023(3):617-624.
Abstract:
Reservoir-bank avalanche is a common hydrogeological problem whether in China or other countries, and analysis of the mechanism of collapse on reservoir bank is an important issue in the field of disaster prevention and mitigation. In virtue of many advantages, e.g., high efficiency and automation, in-site monitoring has become a powerful tool in evaluating reservoir-bank collapse. Nevertheless, in-site monitoring is also subject to some external factors related to remote sensing technology, such as weather conditions, environment, and other factors. Field investigation has the characteristics of flexibility and maneuverability. However, a field investigation is a sampling method based on the observation in the representative area, and the hazard information can not be comprehensively obtained via field investigation in the study area. Common merit for the in-site monitoring and field investigation is that data observed with the methods mentioned above may be used to calibrate the results of the model experiment and numerical simulation, but in-site monitoring or field investigation are not applicable to track the process of a bank collapse. Different from the monitoring or investigating method, an experiment of reservoir-bank collapse under closely monitored or controlled experimental conditions focuses on the regularities of bank collapse from a micro perspective. The model experiment may be conducted in a laboratory far away from the study area, and the experimental scenario may be freely designed if needed. Yet the researchers should consider the similarity of the cumulative effect while designing the downscaled model experiment for reservoir bank failure. Maybe it is easy to simulate and observe the complicated topographical conditions of bank collapse in the field experiment because no change exists in the scale of the underlying surface and properties of erosion material. Usually making accurate observations and simulations is relatively difficult in the field. Numerical simulations have been widely used to analyze and predict the reservoir-bank avalanche from a macro perspective all over the world, whereas the result of the numerical simulation has to be verified with that obtained from monitoring, investigation, or experiment. In summary, each research method presents its own characteristic set of advantages and limitations. Scientists may use an appropriate analysis route according to the objectives and contents of a specific project.Shortly, improved methods for studying the mechanism of avalanches on reservoir banks may be presented through the following aspects: (1) To consider the coupling effects of multiple impact factors in the process of reservoir-bank avalanches. Rainfall, wave, and fluctuation of reservoir water level are the main external factors causing the deformation of landslides. However, how the reservoir-bank avalanche goes coupled with multiple factors is still at the exploratory stage. Hence, to make a further study of the above contents is surely necessary. (2) To study the mechanism of avalanches on reservoir banks with multi-methods. Usually, a single research method may be particularly vulnerable to weather, environment, and other factors, and some methods can not be used to obtain detailed disaster information required by on-site command quickly and comprehensively. In addition, limitations exist in considering all the stress conditions and multi-dimensional stress states of the reservoir slopes. Hence, future research may be focused on combining the strengths and weaknesses of different kinds of research methods to study the formation mechanism and protection measures of reservoir-bank avalanche.
Reservoir-bank avalanche is a common hydrogeological problem whether in China or other countries, and analysis of the mechanism of collapse on reservoir bank is an important issue in the field of disaster prevention and mitigation. In virtue of many advantages, e.g., high efficiency and automation, in-site monitoring has become a powerful tool in evaluating reservoir-bank collapse. Nevertheless, in-site monitoring is also subject to some external factors related to remote sensing technology, such as weather conditions, environment, and other factors. Field investigation has the characteristics of flexibility and maneuverability. However, a field investigation is a sampling method based on the observation in the representative area, and the hazard information can not be comprehensively obtained via field investigation in the study area. Common merit for the in-site monitoring and field investigation is that data observed with the methods mentioned above may be used to calibrate the results of the model experiment and numerical simulation, but in-site monitoring or field investigation are not applicable to track the process of a bank collapse. Different from the monitoring or investigating method, an experiment of reservoir-bank collapse under closely monitored or controlled experimental conditions focuses on the regularities of bank collapse from a micro perspective. The model experiment may be conducted in a laboratory far away from the study area, and the experimental scenario may be freely designed if needed. Yet the researchers should consider the similarity of the cumulative effect while designing the downscaled model experiment for reservoir bank failure. Maybe it is easy to simulate and observe the complicated topographical conditions of bank collapse in the field experiment because no change exists in the scale of the underlying surface and properties of erosion material. Usually making accurate observations and simulations is relatively difficult in the field. Numerical simulations have been widely used to analyze and predict the reservoir-bank avalanche from a macro perspective all over the world, whereas the result of the numerical simulation has to be verified with that obtained from monitoring, investigation, or experiment. In summary, each research method presents its own characteristic set of advantages and limitations. Scientists may use an appropriate analysis route according to the objectives and contents of a specific project.Shortly, improved methods for studying the mechanism of avalanches on reservoir banks may be presented through the following aspects: (1) To consider the coupling effects of multiple impact factors in the process of reservoir-bank avalanches. Rainfall, wave, and fluctuation of reservoir water level are the main external factors causing the deformation of landslides. However, how the reservoir-bank avalanche goes coupled with multiple factors is still at the exploratory stage. Hence, to make a further study of the above contents is surely necessary. (2) To study the mechanism of avalanches on reservoir banks with multi-methods. Usually, a single research method may be particularly vulnerable to weather, environment, and other factors, and some methods can not be used to obtain detailed disaster information required by on-site command quickly and comprehensively. In addition, limitations exist in considering all the stress conditions and multi-dimensional stress states of the reservoir slopes. Hence, future research may be focused on combining the strengths and weaknesses of different kinds of research methods to study the formation mechanism and protection measures of reservoir-bank avalanche.
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