Volume 18,Issue 5,2020 Table of Contents
2020, 18(5):1-12.
Abstract:
The quantile regression model is used to analyze the uncertainty of flood forecasting. The results of preferred value ( median of predicted probability distribution function) and 90% confidence interval of flood forecasting are provided to realize the forecast of flood probability . The performance of probabilistic forecasting obtained by the quantile regression model is evaluated using "accuracy reliability " joint evaluation index . The application results of Meigang Station in the Xinjiang River Basin show that in term o f prediction preferred value, the quantile regression model can further improve the accuracy of the flood forecasting. Simultaneously , the prediction interval results with 90% confidence level provided by the model have higher coverage ( about 90% ) and less dispersion ( less than 0. 20) , which means that the narrow prediction interval contains most of the observation, and the reliability of the forecast interval is strong.
The quantile regression model is used to analyze the uncertainty of flood forecasting. The results of preferred value ( median of predicted probability distribution function) and 90% confidence interval of flood forecasting are provided to realize the forecast of flood probability . The performance of probabilistic forecasting obtained by the quantile regression model is evaluated using "accuracy reliability " joint evaluation index . The application results of Meigang Station in the Xinjiang River Basin show that in term o f prediction preferred value, the quantile regression model can further improve the accuracy of the flood forecasting. Simultaneously , the prediction interval results with 90% confidence level provided by the model have higher coverage ( about 90% ) and less dispersion ( less than 0. 20) , which means that the narrow prediction interval contains most of the observation, and the reliability of the forecast interval is strong.
2020, 18(5):13-37.
Abstract:
The Auto regressive Integrated Moving Average Model( ARIMA ) prediction model of ecological water demand is proposed on the premise of ecological priority and green development . Based on this model, the reserved water rights confirmation model using ecological water rights is developed. Depended on the confirmed reserved water rights, the feasibility in the recon figuration of reserved developmental water rights under the options trading model is explored. The model can avoid the risks between water buyers and water sellers, meanwhile, it can achieve optimal allocation of water resources across river basins. It provides a reference for the determination and reconfiguration of special water rights across river basins. The results show ed that: the ecological water demand has changed greatly due to climate change and policy, Tianjin and Hebei do not have the capacity of reserved water for development, which needs to rely on the unified coordination of the basin scheduling center. and the basin scheduling center can do flexible price configuration based on the possible use of reserved development water in the forecast year, which can optimize the economic and social benefits.
The Auto regressive Integrated Moving Average Model( ARIMA ) prediction model of ecological water demand is proposed on the premise of ecological priority and green development . Based on this model, the reserved water rights confirmation model using ecological water rights is developed. Depended on the confirmed reserved water rights, the feasibility in the recon figuration of reserved developmental water rights under the options trading model is explored. The model can avoid the risks between water buyers and water sellers, meanwhile, it can achieve optimal allocation of water resources across river basins. It provides a reference for the determination and reconfiguration of special water rights across river basins. The results show ed that: the ecological water demand has changed greatly due to climate change and policy, Tianjin and Hebei do not have the capacity of reserved water for development, which needs to rely on the unified coordination of the basin scheduling center. and the basin scheduling center can do flexible price configuration based on the possible use of reserved development water in the forecast year, which can optimize the economic and social benefits.
2020, 18(5):38-56.
Abstract:
Given the limitation of the single weighting method in flood risk assessment and the difficulty of the objective division of risk level, an improved combination weighting-fuzzy clustering algorithm is proposed to carry out the research of flood risk assessment. Co nsidering the three aspects of flood risk, sensitivity and vulner ability, the evaluation index system is constructed. The subjective and objective weights are given by the intuitionistic fuzzy analytic hierarchy process and VC-CRITIC method. The optimal combination is calculated by the game-theory-based combination weighting method. Combination weights are used to calculate the flood risk of different evaluation units, and the Gaussian-mixture-model-based fuzzy clustering algorithm is used to classify the regional flood risk levels. T aking the 100-year flood of the mainstream of the Huai River as an example, the application of the flood risk assessment algorithm was carried out in the Cinanfeizuopian flood control protected zone. The results show that the extremely high-risk area and high-risk ar ea which account for 24. 87% of the total area of the protected area submerge. In areas with large water depth, low to pographic index and high socio-economic value, the evaluation results are more reasonable and reliable. The improved combination weighting-fuzzy clustering algorithm may provide flood disaster risk assessment and disaster prevention and mitigation decision-making in flood control protected zones with technical support.
Given the limitation of the single weighting method in flood risk assessment and the difficulty of the objective division of risk level, an improved combination weighting-fuzzy clustering algorithm is proposed to carry out the research of flood risk assessment. Co nsidering the three aspects of flood risk, sensitivity and vulner ability, the evaluation index system is constructed. The subjective and objective weights are given by the intuitionistic fuzzy analytic hierarchy process and VC-CRITIC method. The optimal combination is calculated by the game-theory-based combination weighting method. Combination weights are used to calculate the flood risk of different evaluation units, and the Gaussian-mixture-model-based fuzzy clustering algorithm is used to classify the regional flood risk levels. T aking the 100-year flood of the mainstream of the Huai River as an example, the application of the flood risk assessment algorithm was carried out in the Cinanfeizuopian flood control protected zone. The results show that the extremely high-risk area and high-risk ar ea which account for 24. 87% of the total area of the protected area submerge. In areas with large water depth, low to pographic index and high socio-economic value, the evaluation results are more reasonable and reliable. The improved combination weighting-fuzzy clustering algorithm may provide flood disaster risk assessment and disaster prevention and mitigation decision-making in flood control protected zones with technical support.
2020, 18(5):57-65.
Abstract:
A meta-analysis was conducted based on the existing literature dataset. The dataset includes thirteen kinds of plants and three ty pes of vegetations ( arbor, shrub, herbal) . We identified the relationship between groundwater table depth and species diversity, species richness, and root depth with soil texture. The results showed that: the ecological depth to the groundwater table is quietly the same in different methods; the suit able ecological depth to the groundwater table is 2. 9 m, and the intimidating ecological depth to the groundwater table is 5. 5 m, respectively, while the fluctuation range is 2. 3~ 3. 9, 4. 0~ 7. 2 m; the suitable and intimidated ecological depth to groundwater table both have a typical correlation with root depth; based on current research, the relationship between the rate of root growth and decline of groundwater table depth determines the status of plant growth. The soil texture control capillary rise and groundwater supply capacity, which is an important factor of ecological depth to the groundwater table.
A meta-analysis was conducted based on the existing literature dataset. The dataset includes thirteen kinds of plants and three ty pes of vegetations ( arbor, shrub, herbal) . We identified the relationship between groundwater table depth and species diversity, species richness, and root depth with soil texture. The results showed that: the ecological depth to the groundwater table is quietly the same in different methods; the suit able ecological depth to the groundwater table is 2. 9 m, and the intimidating ecological depth to the groundwater table is 5. 5 m, respectively, while the fluctuation range is 2. 3~ 3. 9, 4. 0~ 7. 2 m; the suitable and intimidated ecological depth to groundwater table both have a typical correlation with root depth; based on current research, the relationship between the rate of root growth and decline of groundwater table depth determines the status of plant growth. The soil texture control capillary rise and groundwater supply capacity, which is an important factor of ecological depth to the groundwater table.
2020, 18(5):66-73.
Abstract:
The variation of terrestrial water storage from 2003 to 2013 was analyzed using GRACE( Gravity Recovery And Climate Experiment) satellite data and then compared with CPC( Climate Prediction Center) , GLDAS( Global Land Data Assimilation System) hydrological models in North China. The correlation coefficients of GRACE, CPC and GLDAS are 0. 679 and 0. 817, respectively, while GRACE has a str onger correlation with GLDAS. The results showed that: terrestrial water storage and groundwater decreased at a rate of - 1. 8 km3 / a and - 1. 3 km3/ s from 2003 to 2013 after deducting surface water as a whole. It's worth noting that the variation of groundwater presented different stages: increased from 2003 to 2004 and declined from 2005 to 2013, the downward trend had slowed since 2010. GRACE and hydrological models showed that equivalent water height was significantly smaller than the long-term average in 2006 and 2009. The month corresponding to the GRACE maximum was unusual in the two years, compared with the results of the National Bureau of Statistics o f China, the total water resources, surface waterresources, and groundwater resources in the valley area, which corresponded to the natural disasters occurred in those two years.
The variation of terrestrial water storage from 2003 to 2013 was analyzed using GRACE( Gravity Recovery And Climate Experiment) satellite data and then compared with CPC( Climate Prediction Center) , GLDAS( Global Land Data Assimilation System) hydrological models in North China. The correlation coefficients of GRACE, CPC and GLDAS are 0. 679 and 0. 817, respectively, while GRACE has a str onger correlation with GLDAS. The results showed that: terrestrial water storage and groundwater decreased at a rate of - 1. 8 km3 / a and - 1. 3 km3/ s from 2003 to 2013 after deducting surface water as a whole. It's worth noting that the variation of groundwater presented different stages: increased from 2003 to 2004 and declined from 2005 to 2013, the downward trend had slowed since 2010. GRACE and hydrological models showed that equivalent water height was significantly smaller than the long-term average in 2006 and 2009. The month corresponding to the GRACE maximum was unusual in the two years, compared with the results of the National Bureau of Statistics o f China, the total water resources, surface waterresources, and groundwater resources in the valley area, which corresponded to the natural disasters occurred in those two years.
2020, 18(5):74-83.
Abstract:
Poyang Lake and Dongting Lake are currently one of the few large and natural river systems in China that play an irreplaceable role in regulating the flood and maintaining the ecological environment of the Yangtze River Basin. In recent years, due to the superimposed influence of climate change and large-scale water conservancy projects, the change of the hydrological situation of the two lakes has gained considerable attention. Therefore, it is o f great practical significance to reveal the hydrological characteristics of the two lakes and comprehensively analyze the influencing factors for the in-depth understanding of the lake water resource management and the relationship between the rivers and lakes. Taking the water systems of Dongting Lake and Poyang Lake as the research objects, the Mann-Kendall test is used to study the trend and degree of lake water regime evolution through the water level of the two lakes, the runoff of the Yangtze River and the runoff of the two lakes in the past 30 years. Moreover, the overall variation characteristics of hydro logical variables in both lakes and their causes at different periods in 198522014 are analyzed. Through the comparison of the hy drological conditions in both lakes, the law of hydrological variation and its influencing factors in the river-connected lakes in the middle reaches of the Yangtze River are systematically examined.The results show that the water levels of the two lakes in the past 30 years have generally been in three stages of " rising-un steady-declining " . Before 2003, the water levels of Poyang Lake and Dongting Lake generally showed an upward trend, and they are basically in an unstable fluctuation state from 1980 to 20 00. After 2 003, the water level of the two lakes showed an obvious downw ard trend. Mann Kendall analysis showed that the water level of the two lakes may have a significant mutation around 2005, and the m aximum drop of the water level of Po yang Lake and Dong ting Lake is 9. 4% and 3. 4% , respectively, compared with the previous one, indicating that the trend degree of water level change of the two lakes is different, and the sensitivity degree o f water regime change of Po yang Lake is stronger than that of Dongting Lake. The replenishment period of Dongting Lake for the mainstream of the Y ang tze River is from April to October, and for P o yang Lake is from March to August, indicating that the two lakes have different adjustments and compensation effect son the hydrology of the mainstream of the Yangtze River.
Poyang Lake and Dongting Lake are currently one of the few large and natural river systems in China that play an irreplaceable role in regulating the flood and maintaining the ecological environment of the Yangtze River Basin. In recent years, due to the superimposed influence of climate change and large-scale water conservancy projects, the change of the hydrological situation of the two lakes has gained considerable attention. Therefore, it is o f great practical significance to reveal the hydrological characteristics of the two lakes and comprehensively analyze the influencing factors for the in-depth understanding of the lake water resource management and the relationship between the rivers and lakes. Taking the water systems of Dongting Lake and Poyang Lake as the research objects, the Mann-Kendall test is used to study the trend and degree of lake water regime evolution through the water level of the two lakes, the runoff of the Yangtze River and the runoff of the two lakes in the past 30 years. Moreover, the overall variation characteristics of hydro logical variables in both lakes and their causes at different periods in 198522014 are analyzed. Through the comparison of the hy drological conditions in both lakes, the law of hydrological variation and its influencing factors in the river-connected lakes in the middle reaches of the Yangtze River are systematically examined.The results show that the water levels of the two lakes in the past 30 years have generally been in three stages of " rising-un steady-declining " . Before 2003, the water levels of Poyang Lake and Dongting Lake generally showed an upward trend, and they are basically in an unstable fluctuation state from 1980 to 20 00. After 2 003, the water level of the two lakes showed an obvious downw ard trend. Mann Kendall analysis showed that the water level of the two lakes may have a significant mutation around 2005, and the m aximum drop of the water level of Po yang Lake and Dong ting Lake is 9. 4% and 3. 4% , respectively, compared with the previous one, indicating that the trend degree of water level change of the two lakes is different, and the sensitivity degree o f water regime change of Po yang Lake is stronger than that of Dongting Lake. The replenishment period of Dongting Lake for the mainstream of the Y ang tze River is from April to October, and for P o yang Lake is from March to August, indicating that the two lakes have different adjustments and compensation effect son the hydrology of the mainstream of the Yangtze River.
2020, 18(5):84-93.
Abstract:
Based on two kinds of high spatial and temporal resolution daily rainfall time series data from 1951 to 2015, 11 extreme rainfall indices are selected to comprehensively characterize the multi-scale non-linear spatial and temporal evolution o f extreme rainfall events in Guangxiusing Mann-Kendall ( M2K ) test and pole symmetric mode decomposition. The results show that: except for continuo us wetday s ( CWD) and moderate rainy days ( R10 ) , the other 9 extreme rainfall indices showed a downward trend, and the rest of the other 9 indices showed a significant increasing trend from 1951 to 2015 in Guang xi, the high-value area of the CDD ( continuo us dry-day ) index in Guangxi is located in western and eastern Guangxi, while the other indexes show the decreasing spatial distribution characteristics from northeast and south to southwest and northwest Guang xi, various extreme rainfall indices show that the evolution o f extreme rainfall in Guang xi occurs mainly in the vicinity of 2008 to 2010, there are 2.85 - 3.34 a and 5.34 - 9.19 a interdecadal quasi-cycles in the evolution of extreme rainfall in Guang x i, and 10 .09 - 17.11 a and 22. 35 - 35.62 a interdecadal quasi-cycles, respectively, and the fluctuation of multiple cycles is mainly due to the contribution of the interannual variation of extreme rainfall.
Based on two kinds of high spatial and temporal resolution daily rainfall time series data from 1951 to 2015, 11 extreme rainfall indices are selected to comprehensively characterize the multi-scale non-linear spatial and temporal evolution o f extreme rainfall events in Guangxiusing Mann-Kendall ( M2K ) test and pole symmetric mode decomposition. The results show that: except for continuo us wetday s ( CWD) and moderate rainy days ( R10 ) , the other 9 extreme rainfall indices showed a downward trend, and the rest of the other 9 indices showed a significant increasing trend from 1951 to 2015 in Guang xi, the high-value area of the CDD ( continuo us dry-day ) index in Guangxi is located in western and eastern Guangxi, while the other indexes show the decreasing spatial distribution characteristics from northeast and south to southwest and northwest Guang xi, various extreme rainfall indices show that the evolution o f extreme rainfall in Guang xi occurs mainly in the vicinity of 2008 to 2010, there are 2.85 - 3.34 a and 5.34 - 9.19 a interdecadal quasi-cycles in the evolution of extreme rainfall in Guang x i, and 10 .09 - 17.11 a and 22. 35 - 35.62 a interdecadal quasi-cycles, respectively, and the fluctuation of multiple cycles is mainly due to the contribution of the interannual variation of extreme rainfall.
2020, 18(5):94-101.
Abstract:
According to the distribution of water system in Yuanhe River Basin, the water supply and demand with or without consideration of eng ineering capacity is analyzed, which are divided based on the characteristics of town and sub-basin. The analysis displays the spatial and temporal variations of the water supply and demand to support water resources management, particularly in the major towns. The r esult shows that: the w ater demands can no t be met under the 95% fr equency, with the sho rtag e rate of 61 7% in 2025 and 71 7% in 2035, furthermor e, considering eng ineering capacity under the 95% fr equency, the sho rtag e rates of the basin incr ease to 16. 6% in 2025 and 17.5% in 2035. The areas of water shortage are mainly focused on the mainstream of Yuanhe River Basin, particularly in Lux i, Yuanzhou, Fenyi, and Yushui, with significant differences in characteristics in a year.
According to the distribution of water system in Yuanhe River Basin, the water supply and demand with or without consideration of eng ineering capacity is analyzed, which are divided based on the characteristics of town and sub-basin. The analysis displays the spatial and temporal variations of the water supply and demand to support water resources management, particularly in the major towns. The r esult shows that: the w ater demands can no t be met under the 95% fr equency, with the sho rtag e rate of 61 7% in 2025 and 71 7% in 2035, furthermor e, considering eng ineering capacity under the 95% fr equency, the sho rtag e rates of the basin incr ease to 16. 6% in 2025 and 17.5% in 2035. The areas of water shortage are mainly focused on the mainstream of Yuanhe River Basin, particularly in Lux i, Yuanzhou, Fenyi, and Yushui, with significant differences in characteristics in a year.
2020, 18(5):102-108.
Abstract:
Flood disaster is one of the major natural disasters in Songhua River Basin. In particular, the confluence of Nenjiang River and Songhua River( hereinafter referred as the two rivers) encounter often causes flood. The encounter phenomenon of two rivers flood is taken as the engineering background. Based on historical flood data of the two rivers, two methods of statistics and Copula function are respectively adopted to qualitatively analyze the flood peak encounter and flood process encounter of the two rivers, and quantitatively obtain the encounter risks of the two rivers indifferent time periods and flood combinations of different magnitudes, in o rder to make the Songhua River Basin, especially the two river junctions and its flood control safety in downstream areas provides a valuable reference. The results of the two methods are the same, and the conclusion is credible. Flood encounter can be avoided by upstream water regulation.
Flood disaster is one of the major natural disasters in Songhua River Basin. In particular, the confluence of Nenjiang River and Songhua River( hereinafter referred as the two rivers) encounter often causes flood. The encounter phenomenon of two rivers flood is taken as the engineering background. Based on historical flood data of the two rivers, two methods of statistics and Copula function are respectively adopted to qualitatively analyze the flood peak encounter and flood process encounter of the two rivers, and quantitatively obtain the encounter risks of the two rivers indifferent time periods and flood combinations of different magnitudes, in o rder to make the Songhua River Basin, especially the two river junctions and its flood control safety in downstream areas provides a valuable reference. The results of the two methods are the same, and the conclusion is credible. Flood encounter can be avoided by upstream water regulation.
2020, 18(5):109-114.
Abstract:
Through collecting and investigating a large amount of hydrology , geology , water resources, and engineering technical data, the paper discusses the optimization of the western route project scheme, and puts forward the main problems faced by the eng ineering research on the basis of the existing research; using the multi-index comparison method, starting from the water diversion section downward moving gravity flow scheme and pumping scheme of the west line project , discuss the pros and cons of the plan th rough indicators such as the adjustable river water volume, environmental impact, resettlement scope, investment cost and economic benefit, and demonstrate the feasibility and superiority of the project shifting the gravity flow plan. Simultaneously , in order to reduce the impact of water transfer on ecology , environment, society and other aspects, the Jinsha River, Ya long River , and Dadu River have been analyzed and drafted for an average annual water transfer volume of 17 ×109 m3 . The research results can provide an important technical basis for future engineering construction decisions.
Through collecting and investigating a large amount of hydrology , geology , water resources, and engineering technical data, the paper discusses the optimization of the western route project scheme, and puts forward the main problems faced by the eng ineering research on the basis of the existing research; using the multi-index comparison method, starting from the water diversion section downward moving gravity flow scheme and pumping scheme of the west line project , discuss the pros and cons of the plan th rough indicators such as the adjustable river water volume, environmental impact, resettlement scope, investment cost and economic benefit, and demonstrate the feasibility and superiority of the project shifting the gravity flow plan. Simultaneously , in order to reduce the impact of water transfer on ecology , environment, society and other aspects, the Jinsha River, Ya long River , and Dadu River have been analyzed and drafted for an average annual water transfer volume of 17 ×109 m3 . The research results can provide an important technical basis for future engineering construction decisions.
2020, 18(5):115-122.
Abstract:
Learning from the successful experience of hydraulic design standardization of water turbine drafttube, the excellent tubular pump system with front-positioned shaft are used for more and better in the pumping station with low head and extra low head. Therefore, the standardization of hydraulic design for conduits of tubular pump system with front-positioned shaft has been premeditated in depth. The statistical rules of conduit sizes of the tubular pump with front-positioned shaft are analyzed, and the series of hydraulic design schemes for the inlet and outlet conduits are reasonably graded. Taking the shaft width and the nominal average velocity of the pump as key parameters, 24 schemes of hydraulic design standardization of the inlet conduit are obtained. Furthermore, 17 schemes of hydraulic design standardization of the outlet conduit are obtained by taking the outlet section width of the outlet conduit and the nominal average velocity of the pump as key parameters. According to the results of the optimal hydraulic design calculation, the hydraulic performances of the 24 inlet conduit schemes and the 17 outlet conduit schemes are excellent.The hydraulic design standardization for the inlet and out let conduit of tubular pump system with the front-positioned shaft is studied for the first time at home and abroad, and it is of great significance to improve the design level of pumping stations with low head.
Learning from the successful experience of hydraulic design standardization of water turbine drafttube, the excellent tubular pump system with front-positioned shaft are used for more and better in the pumping station with low head and extra low head. Therefore, the standardization of hydraulic design for conduits of tubular pump system with front-positioned shaft has been premeditated in depth. The statistical rules of conduit sizes of the tubular pump with front-positioned shaft are analyzed, and the series of hydraulic design schemes for the inlet and outlet conduits are reasonably graded. Taking the shaft width and the nominal average velocity of the pump as key parameters, 24 schemes of hydraulic design standardization of the inlet conduit are obtained. Furthermore, 17 schemes of hydraulic design standardization of the outlet conduit are obtained by taking the outlet section width of the outlet conduit and the nominal average velocity of the pump as key parameters. According to the results of the optimal hydraulic design calculation, the hydraulic performances of the 24 inlet conduit schemes and the 17 outlet conduit schemes are excellent.The hydraulic design standardization for the inlet and out let conduit of tubular pump system with the front-positioned shaft is studied for the first time at home and abroad, and it is of great significance to improve the design level of pumping stations with low head.
2020, 18(5):123-129.
Abstract:
In order to realize the longterm and stable service of the dam and avoid the influence of gross errors in the monitoring data on the dam safety monitoring results, it is necessary to eliminate the gross errors in the monitoring data. Because the current gross error recognition method can still cause the gross error to be missed or misjudged, an automatic gross error recognition method based on image processing technology by imitating the process of manual data gross error recognition and using a programming language. T he scatter map drawn according to the monitoring data is processed by Gaussian blur and binarization, the main trend line is extracted, and the gross error in the monitoring data is identified and eliminated. The monitoring data of a real dam are selected, the gross error is identified, and the results are compared with those of the traditional 3 identification criteria. The results show that: the recognition effect of the method is more significant, the applied met hod avoids the false negatives of gross errors and eliminates gross errors more tho roughly, in addition, the complex correlation coefficient of the statistical model obtained by the method is 0. 999, while the standard dev iation is 0. 192, which shows that the accuracy of the model is higher and the model is more in line with the actual situation of the project. Therefore, the method has a certain engineering application prospect and practical value.
In order to realize the longterm and stable service of the dam and avoid the influence of gross errors in the monitoring data on the dam safety monitoring results, it is necessary to eliminate the gross errors in the monitoring data. Because the current gross error recognition method can still cause the gross error to be missed or misjudged, an automatic gross error recognition method based on image processing technology by imitating the process of manual data gross error recognition and using a programming language. T he scatter map drawn according to the monitoring data is processed by Gaussian blur and binarization, the main trend line is extracted, and the gross error in the monitoring data is identified and eliminated. The monitoring data of a real dam are selected, the gross error is identified, and the results are compared with those of the traditional 3 identification criteria. The results show that: the recognition effect of the method is more significant, the applied met hod avoids the false negatives of gross errors and eliminates gross errors more tho roughly, in addition, the complex correlation coefficient of the statistical model obtained by the method is 0. 999, while the standard dev iation is 0. 192, which shows that the accuracy of the model is higher and the model is more in line with the actual situation of the project. Therefore, the method has a certain engineering application prospect and practical value.
2020, 18(5):130-138.
Abstract:
The implementation of the " cut and bend" project of the Ningxia Ping luo Sipaikou 82shaped river channel caused a drastic change in the riverbed boundary conditions. In order to grasp the development and evolution rules of water movement, sediment movement, and river bed migration and evolution in the artificialexcavation of the river after the project operation, the project team went to the Sipikou of the Yellow River in Pingluo for site inspections and field measurements. A series of sedimentation test sections were set up acco rding to the actual terrain, current flow conditions, and preliminary forecasted river bed deformation rules of the studied river sections. The subsequent field measurements were carried out to obtain the river bed evolution laws and suspended sediments of this channel, the distribution law of particle size and sediment content, and the evolution of the mainstream of the river under the influence of shoals on the bank. Based on the actual measurement , the average degree of erosion ( 1. 607 7 m) , deposition of the river bed, and the overall scouring amount ( 356. 490 8 × 104 m3 ) of the river section were calculated and analyzed. The analysis result s suggested the strengthening of the left bank slope of the Spur Group.
The implementation of the " cut and bend" project of the Ningxia Ping luo Sipaikou 82shaped river channel caused a drastic change in the riverbed boundary conditions. In order to grasp the development and evolution rules of water movement, sediment movement, and river bed migration and evolution in the artificialexcavation of the river after the project operation, the project team went to the Sipikou of the Yellow River in Pingluo for site inspections and field measurements. A series of sedimentation test sections were set up acco rding to the actual terrain, current flow conditions, and preliminary forecasted river bed deformation rules of the studied river sections. The subsequent field measurements were carried out to obtain the river bed evolution laws and suspended sediments of this channel, the distribution law of particle size and sediment content, and the evolution of the mainstream of the river under the influence of shoals on the bank. Based on the actual measurement , the average degree of erosion ( 1. 607 7 m) , deposition of the river bed, and the overall scouring amount ( 356. 490 8 × 104 m3 ) of the river section were calculated and analyzed. The analysis result s suggested the strengthening of the left bank slope of the Spur Group.
2020, 18(5):139-143.
Abstract:
The simplified solution of the hydraulic jump equation is provided by analyzing the hydraulic characteristics of a hydraulic jump in an abruptly expanding channel. Based on analyzing the flow pattern of a hydraulic jump in an abruptly expanding channel, a hypothesis is made for the depth in the back-flow region considering the effect of the abruptly expanding ratioon the depth in the back-flow region. The law of momentum conserv ation is used to est ablish the hydraulic jump equation in an abruptly expanding channel. Through the a pproximate treatment, the explicit simplified solution of the hydraulic jump equation in an abruptly expanding channel is derived. An empirical formula for the related parameters is given. The averageerr or between the simplified solution and the experimental result is 1.924% at an abruptly expanding ratio when β= 1.0. The error between the classical solution and the simplified solution in the range of 3.0< Fr 1 < 9.0 decreases with the increase of the flow Froude number and the max imum error is less than 3.001 % . The sim plified solution well agrees with the experiment and the classical solution of 2D hydraulic jump. The average error of the simplified solution and the experimental result under different abrupt expanding ratio is 5.511% , indicating good accuracy. Therefore, it can be applied to carry out the hydraulic calculation in the downstream of the outlet structure.
The simplified solution of the hydraulic jump equation is provided by analyzing the hydraulic characteristics of a hydraulic jump in an abruptly expanding channel. Based on analyzing the flow pattern of a hydraulic jump in an abruptly expanding channel, a hypothesis is made for the depth in the back-flow region considering the effect of the abruptly expanding ratioon the depth in the back-flow region. The law of momentum conserv ation is used to est ablish the hydraulic jump equation in an abruptly expanding channel. Through the a pproximate treatment, the explicit simplified solution of the hydraulic jump equation in an abruptly expanding channel is derived. An empirical formula for the related parameters is given. The averageerr or between the simplified solution and the experimental result is 1.924% at an abruptly expanding ratio when β= 1.0. The error between the classical solution and the simplified solution in the range of 3.0< Fr 1 < 9.0 decreases with the increase of the flow Froude number and the max imum error is less than 3.001 % . The sim plified solution well agrees with the experiment and the classical solution of 2D hydraulic jump. The average error of the simplified solution and the experimental result under different abrupt expanding ratio is 5.511% , indicating good accuracy. Therefore, it can be applied to carry out the hydraulic calculation in the downstream of the outlet structure.
2020, 18(5):144-150.
Abstract:
In order to obtain the optimal design scheme of the inlet and outlet passages of a large vertical mixed flow pumping station, the numerical simulation of the flow pattern in the inlet and outlet passages is carried out using the CFX software. Based on the preliminary design scheme of the inlet and outlet passages of the pumping station, the inlet passage optimization scheme is obtained by adjusting the section parameters of the inlet passage. The optimum design scheme is determined by changing the rising and falling angles of the siphon outlet passages. The final results show that: when the relationship between the inlet passage flow velocity and the length of the passage, the section area and the length of the passage is smooth and there is no sudden change, indicating that it meets the optimization design requirements, likewise, the rising angle of the outlet passage is 22 degrees and the falling angle is 29 degrees, respectively, the velocity distribution of the outlet passage is more uniform and the hydraulic loss is the smallest . T he results obtained can be used to guide the passage optimization of large and medium-sized pumping stations.
In order to obtain the optimal design scheme of the inlet and outlet passages of a large vertical mixed flow pumping station, the numerical simulation of the flow pattern in the inlet and outlet passages is carried out using the CFX software. Based on the preliminary design scheme of the inlet and outlet passages of the pumping station, the inlet passage optimization scheme is obtained by adjusting the section parameters of the inlet passage. The optimum design scheme is determined by changing the rising and falling angles of the siphon outlet passages. The final results show that: when the relationship between the inlet passage flow velocity and the length of the passage, the section area and the length of the passage is smooth and there is no sudden change, indicating that it meets the optimization design requirements, likewise, the rising angle of the outlet passage is 22 degrees and the falling angle is 29 degrees, respectively, the velocity distribution of the outlet passage is more uniform and the hydraulic loss is the smallest . T he results obtained can be used to guide the passage optimization of large and medium-sized pumping stations.
2020, 18(5):151-156.
Abstract:
In order to solve the problem of vortex belt, vortex and hydraulic pulsation in the water delivery pipeline of an irrigation pump station when multiple units a rerunning , the pump house has a large vibration. Through the establishment of a three dimensional finite element model of the structure of the pumping station building , using ABAQUS software and Lanczos method to extract the structur almo de of the pumping station building, the naturalvibration frequency and vibration mode of the pumping station building are analyzed. The vibration source and the cause of the vibration of the power house are determined, and the possible vibration source and frequency characteristics of the pumping station are determined. The vibration source is verified and analyzed with the theoretical calculation v alue of the main excitation source frequency of the pumping station unit. The results show that: there is resonance phenomenon betw een the excit ation source frequency of the pumping station unit and the natural vibration frequency of the powerhouse structure. The r esearch results can provide a theoretical basis for the maint enance and reinforcement of the pumping station.
In order to solve the problem of vortex belt, vortex and hydraulic pulsation in the water delivery pipeline of an irrigation pump station when multiple units a rerunning , the pump house has a large vibration. Through the establishment of a three dimensional finite element model of the structure of the pumping station building , using ABAQUS software and Lanczos method to extract the structur almo de of the pumping station building, the naturalvibration frequency and vibration mode of the pumping station building are analyzed. The vibration source and the cause of the vibration of the power house are determined, and the possible vibration source and frequency characteristics of the pumping station are determined. The vibration source is verified and analyzed with the theoretical calculation v alue of the main excitation source frequency of the pumping station unit. The results show that: there is resonance phenomenon betw een the excit ation source frequency of the pumping station unit and the natural vibration frequency of the powerhouse structure. The r esearch results can provide a theoretical basis for the maint enance and reinforcement of the pumping station.
2020, 18(5):157-164.
Abstract:
The core area of Huixian karst wetland is selected as the research object. Based on the geological and hydro geological conditions of the research area, the concept model of hydrogeology is generalized. Using Visual MODFLOW software, the distribution characteristics of groundwater in the Huixian wetland are simulated. The model identification, and verification showed that the simulated water level and the observed water level achieved a good fitting effect. Based on the simulation results, the dynamic change of groundwater in the research area is analyzed, and the water balance in each simulation period is calculated. The results show that: the g roundwater in the study area is generally decreasing from north to south, the groundwater level in the northern recharge area is highest, the groundwater level in the southwest drainage area is the lowest, and the average difference between the north and the south groundwater level is 7.34 m, respectively; the dynamic change of water level is greatly affected by rainfall intensity , showing obvious seasonal change rule; in the southern part of the pond, Mudong lake, and other drainage zones, the water supply is sufficient , and the underg ro und water is under control; the variation range of water level is not more than 1 m, and the variation range of water level in the northern recharge area is more than 3 m, the total recharge amount of groundwater in the simulation period is 442. 729 2 million m3 / a, after water balance calculation, of which the rainfall infiltration.recharge accounts for 76.85% , the total discharge of gro undw ater is 427.306 million m3 / a, and the exploitation and evaporation of groundwater account for 33.86% and 36.63% respectively ; the study area is generally in a positive equilibrium state in the simulation period, and the degradation of wetland directly affects flood control, storage capacity , water conservation, and water storage capacity , which refelcts the phenomenon of " excessive drought in drought periods and excessive waterlogging during floods" .
The core area of Huixian karst wetland is selected as the research object. Based on the geological and hydro geological conditions of the research area, the concept model of hydrogeology is generalized. Using Visual MODFLOW software, the distribution characteristics of groundwater in the Huixian wetland are simulated. The model identification, and verification showed that the simulated water level and the observed water level achieved a good fitting effect. Based on the simulation results, the dynamic change of groundwater in the research area is analyzed, and the water balance in each simulation period is calculated. The results show that: the g roundwater in the study area is generally decreasing from north to south, the groundwater level in the northern recharge area is highest, the groundwater level in the southwest drainage area is the lowest, and the average difference between the north and the south groundwater level is 7.34 m, respectively; the dynamic change of water level is greatly affected by rainfall intensity , showing obvious seasonal change rule; in the southern part of the pond, Mudong lake, and other drainage zones, the water supply is sufficient , and the underg ro und water is under control; the variation range of water level is not more than 1 m, and the variation range of water level in the northern recharge area is more than 3 m, the total recharge amount of groundwater in the simulation period is 442. 729 2 million m3 / a, after water balance calculation, of which the rainfall infiltration.recharge accounts for 76.85% , the total discharge of gro undw ater is 427.306 million m3 / a, and the exploitation and evaporation of groundwater account for 33.86% and 36.63% respectively ; the study area is generally in a positive equilibrium state in the simulation period, and the degradation of wetland directly affects flood control, storage capacity , water conservation, and water storage capacity , which refelcts the phenomenon of " excessive drought in drought periods and excessive waterlogging during floods" .
2020, 18(5):165-173.
Abstract:
A ground source heat pump system in Anyang was used as the research object. The water balance method was used to predict the change of groundwater level in Anyang , and the groundwater water-heat coupling model of groundwater level change was constructed to quantify the impact of different well group operations. The optimization theory was used to establish a well group control model to optimize the layout of the well group. The results showed that: when the production pressure increased to 3×10 7 m3 and the groundwater level raised by 5.7 m, the best scheme for well group layout was linear on interphase pumping wells, whereas, when the production pressure increased to 5×10 7 m3 and the groundwater level increased by 8.4 m, the best plan for well group layout was rectangular on different sides of the pumping well.
A ground source heat pump system in Anyang was used as the research object. The water balance method was used to predict the change of groundwater level in Anyang , and the groundwater water-heat coupling model of groundwater level change was constructed to quantify the impact of different well group operations. The optimization theory was used to establish a well group control model to optimize the layout of the well group. The results showed that: when the production pressure increased to 3×10 7 m3 and the groundwater level raised by 5.7 m, the best scheme for well group layout was linear on interphase pumping wells, whereas, when the production pressure increased to 5×10 7 m3 and the groundwater level increased by 8.4 m, the best plan for well group layout was rectangular on different sides of the pumping well.
19 Application of stratified pumping test in hydrogeological exploration of lager thickness aquifers
2020, 18(5):174-181.
Abstract:
Water inflow , water quality and other parameters of several aquifers with a buried depth of 24 0 m and a thickness of 660 m for large thickness aquifers. Based on borehole core and logging data, the well is divided into 6 pumping section. The results showed that : the average hydraulic conductivity of the Luo he and Huanhe aquifer is lower than that in the upper section in the study area, there is a lmo st no hy draulic connectio n betw een the upper and lower aquifers of the same aquifer group, the upper of the Luo he a quifer is rich in high-quality freshwater resources, which can be used as a target mining layer for urban concentr ated water sources, and simultaneously prevent over-exploitation and lead to poor water quality, the stratified pum ping test with new packer technology may effectively solve the difficulty of obtaining hydrogeological parameters of larget hickness aquifers, which not only improve the a ccur acy of the survey but also obtain accurate and reliable hydrogeological parameters. Therefore, it is of great significance to clarify the flow relationship between aquifers and to rationally plan the exploitation and utilization of groundwater.
Water inflow , water quality and other parameters of several aquifers with a buried depth of 24 0 m and a thickness of 660 m for large thickness aquifers. Based on borehole core and logging data, the well is divided into 6 pumping section. The results showed that : the average hydraulic conductivity of the Luo he and Huanhe aquifer is lower than that in the upper section in the study area, there is a lmo st no hy draulic connectio n betw een the upper and lower aquifers of the same aquifer group, the upper of the Luo he a quifer is rich in high-quality freshwater resources, which can be used as a target mining layer for urban concentr ated water sources, and simultaneously prevent over-exploitation and lead to poor water quality, the stratified pum ping test with new packer technology may effectively solve the difficulty of obtaining hydrogeological parameters of larget hickness aquifers, which not only improve the a ccur acy of the survey but also obtain accurate and reliable hydrogeological parameters. Therefore, it is of great significance to clarify the flow relationship between aquifers and to rationally plan the exploitation and utilization of groundwater.
2020, 18(5):182-192.
Abstract:
In order to deeply explore the relationship between meteorological factors and summer maize yield, the annual yield data and related meteor ological factors in Hebei Province were analyzed using different methods such as climate propensity rate, M2K mutation test, and correlation test. Based on this, the relevance and the degree of action of the two are discussed. The results showed that: the av erage, maximum and minimum temperatures in Hebei Province showed a significant upward trend, while the sunshine hours, precipitation, relative humidity, and wind speed showed a significant downward trend; from 1960 to 2017, the meteorological output of summer corn in Hebei Province was significantly reduced at - 568 kg/ hm2 per 10 a; meteorological output is negatively related to average temperature, maximum temperature, minimum temperature, and is positively related to sunshine hours, precipitation, relative humidity, and wind speed; precipitation, minimum temperature and wind speed are the key factors affecting the meteorological output of summer maize in Hebei Province. The research results can provide theoretical support for optimizing the structure of agricultural resources and promoting the sustainable development of regional agriculture.
In order to deeply explore the relationship between meteorological factors and summer maize yield, the annual yield data and related meteor ological factors in Hebei Province were analyzed using different methods such as climate propensity rate, M2K mutation test, and correlation test. Based on this, the relevance and the degree of action of the two are discussed. The results showed that: the av erage, maximum and minimum temperatures in Hebei Province showed a significant upward trend, while the sunshine hours, precipitation, relative humidity, and wind speed showed a significant downward trend; from 1960 to 2017, the meteorological output of summer corn in Hebei Province was significantly reduced at - 568 kg/ hm2 per 10 a; meteorological output is negatively related to average temperature, maximum temperature, minimum temperature, and is positively related to sunshine hours, precipitation, relative humidity, and wind speed; precipitation, minimum temperature and wind speed are the key factors affecting the meteorological output of summer maize in Hebei Province. The research results can provide theoretical support for optimizing the structure of agricultural resources and promoting the sustainable development of regional agriculture.
2020, 18(5):193-201.
Abstract:
The Log arithrnic Mean Divisin Index ( LMDI) index decomposition model are used to divide the driving factors of agricultural virtual w ater content change into structural, intensity, economic and demand effects in the five northwest provinces( autonomous regions) from the 11th Five-Year plan and 12th Five-Year plan to explore their contributions and its spatial-temporal differences. The research results show that: the agricultural virtual water content in the product structure distribution, livest ock products> the three major staples> commercial crops. From the perspective of time, from 2006 to 2015, the agricultural virtual water content in the whole region showed a trend of rising-falling-rising. The economic effects and intensity effects were the main promoting and inhibitory factors of the virtual water content change. In general, Economic effect> intensity effect> structural effect> demand effect, respectively . During the 11th Five-Year Plan period, the change of virtual water content in the region was mainly affected by regional economic grow th. During the 12th Five-Year Plan period, agricultural production structure the adjustment has gradually inhibited the growth of virtual water content. From a spatial perspective, the inter-provincial difference in the total effect of the change invirtual water co ntent is sig nificant in the five provinces( autonomous regions) from 2006 to 2015. Xinjiang has the strongest positive effect at 11 9.426 × 1010 m3 , followed by Ningxia, Qinghai, and Shaanxi. Negative effects in Gansu is strongest dropped by 9.411×109 m3 . Based o n this, suggestions from the aspects of improving agricultural production technolog y, adjusting the production structure, compensating the water ecological environment to reduce the virtual water content in agriculture, improving the utilization of water resources, and promoting the coordinated development of regional economics and ecology .
The Log arithrnic Mean Divisin Index ( LMDI) index decomposition model are used to divide the driving factors of agricultural virtual w ater content change into structural, intensity, economic and demand effects in the five northwest provinces( autonomous regions) from the 11th Five-Year plan and 12th Five-Year plan to explore their contributions and its spatial-temporal differences. The research results show that: the agricultural virtual water content in the product structure distribution, livest ock products> the three major staples> commercial crops. From the perspective of time, from 2006 to 2015, the agricultural virtual water content in the whole region showed a trend of rising-falling-rising. The economic effects and intensity effects were the main promoting and inhibitory factors of the virtual water content change. In general, Economic effect> intensity effect> structural effect> demand effect, respectively . During the 11th Five-Year Plan period, the change of virtual water content in the region was mainly affected by regional economic grow th. During the 12th Five-Year Plan period, agricultural production structure the adjustment has gradually inhibited the growth of virtual water content. From a spatial perspective, the inter-provincial difference in the total effect of the change invirtual water co ntent is sig nificant in the five provinces( autonomous regions) from 2006 to 2015. Xinjiang has the strongest positive effect at 11 9.426 × 1010 m3 , followed by Ningxia, Qinghai, and Shaanxi. Negative effects in Gansu is strongest dropped by 9.411×109 m3 . Based o n this, suggestions from the aspects of improving agricultural production technolog y, adjusting the production structure, compensating the water ecological environment to reduce the virtual water content in agriculture, improving the utilization of water resources, and promoting the coordinated development of regional economics and ecology .
2020, 18(5):202-208.
Abstract:
To determine the suitable irrigation schedule for alfalfa under shallow embedded drip irrigation in pebbly sandy soil, five irrigat ion quotas ( 22.5 mm, 30.0 mm, 37.5 mm, 45.0 mm, and 52.5 mm) were set in the experiment, and the surface irrigation was used as the control group ( CK) to study the effect of irrigation quota on the water consumption and yield of shallow embedded drip irrigation alfalfa. The results showed that the water consumption intensity of alfalfa in different stubbles under different irrigation quota was expressed as 2nd> 1st> 3rd, and all of them reached the peak value in the bud stage. The total water consumption of alfalfa in differ ent stubbles was expressed as 2nd> 3r d> 1st, and the water consumption was the highest in the branching stage, the initial flowering stage, and the bud stage, respectively . When the irrigation quota was greater than 45.0mm, the increasing trend of water consumption intensity was smaller and similar to that of surface irrigation ( CK) . There was no significant difference in water consumption betw een 45.0 mm irrigation quota and CK ( P < 01 05) . There were no significant differences in total water consumption, total yield and to tal water use efficiency between high irrigation quota ( 45.0, 52.5 mm) and surface irrigation ( CK) , but significant difference was found between low irrigation quota ( 22.5, 30.0, 37.5 mm) ( P < 0.05) . The total yield and total water use efficiency reached the max imum at the irrigation quota of 45.0 mm, increased by 9.05% and 14.54% , respectively compared with the surface irrigation ( CK) . T herefore, it is suitable to select a 45.0 mm irrigation quota and 540 mm irrigation norm for alfalfa in pebbly sandy soil with a sha llow embedded drip irrigation system.
To determine the suitable irrigation schedule for alfalfa under shallow embedded drip irrigation in pebbly sandy soil, five irrigat ion quotas ( 22.5 mm, 30.0 mm, 37.5 mm, 45.0 mm, and 52.5 mm) were set in the experiment, and the surface irrigation was used as the control group ( CK) to study the effect of irrigation quota on the water consumption and yield of shallow embedded drip irrigation alfalfa. The results showed that the water consumption intensity of alfalfa in different stubbles under different irrigation quota was expressed as 2nd> 1st> 3rd, and all of them reached the peak value in the bud stage. The total water consumption of alfalfa in differ ent stubbles was expressed as 2nd> 3r d> 1st, and the water consumption was the highest in the branching stage, the initial flowering stage, and the bud stage, respectively . When the irrigation quota was greater than 45.0mm, the increasing trend of water consumption intensity was smaller and similar to that of surface irrigation ( CK) . There was no significant difference in water consumption betw een 45.0 mm irrigation quota and CK ( P < 01 05) . There were no significant differences in total water consumption, total yield and to tal water use efficiency between high irrigation quota ( 45.0, 52.5 mm) and surface irrigation ( CK) , but significant difference was found between low irrigation quota ( 22.5, 30.0, 37.5 mm) ( P < 0.05) . The total yield and total water use efficiency reached the max imum at the irrigation quota of 45.0 mm, increased by 9.05% and 14.54% , respectively compared with the surface irrigation ( CK) . T herefore, it is suitable to select a 45.0 mm irrigation quota and 540 mm irrigation norm for alfalfa in pebbly sandy soil with a sha llow embedded drip irrigation system.
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