Volume 16,Issue 3,2018 Table of Contents
2018, 16(3):1-9.
Abstract:
Evapotranspiration (ET) plays a critical role in linking the water and energy cycle. Accurately estimating ET is important for hydrologic study and supports the optimal allocation and sustainable use of water resources. In this study, monthly precipitation data, runoff data, and GRACE terrestrial water storage data were used to estimate ET with the water balance approach ( ET_WB ) as the reference. 9 ET products, including land surface model products ET_clm, ET_noah, ET_mos and ET_vic, reanalysis product ET_jra, model tree set-based flux obser vation products ET_jung, and energy balance-based diagnosis models ET_modis, ET_PML, and ET_Zhangke, were compared in the Hanjiang River Basin. The results showed that the model tree set-based flux observation product and energy balance-based diagnosis model products had better accuracy, followed by the reanalysis product and the land surface model products. ET_jung , ET_modis, and ET_clm had a good correlation with ET_ WB on the monthly scale. ET_noah, ET_mos, and ET_vic had large error among the 9 products. This study can provide a scientific reference for the hydrologic study of the Han River and the management of the Middle Route of the South-to-North Water Transfer Project.
Evapotranspiration (ET) plays a critical role in linking the water and energy cycle. Accurately estimating ET is important for hydrologic study and supports the optimal allocation and sustainable use of water resources. In this study, monthly precipitation data, runoff data, and GRACE terrestrial water storage data were used to estimate ET with the water balance approach ( ET_WB ) as the reference. 9 ET products, including land surface model products ET_clm, ET_noah, ET_mos and ET_vic, reanalysis product ET_jra, model tree set-based flux obser vation products ET_jung, and energy balance-based diagnosis models ET_modis, ET_PML, and ET_Zhangke, were compared in the Hanjiang River Basin. The results showed that the model tree set-based flux observation product and energy balance-based diagnosis model products had better accuracy, followed by the reanalysis product and the land surface model products. ET_jung , ET_modis, and ET_clm had a good correlation with ET_ WB on the monthly scale. ET_noah, ET_mos, and ET_vic had large error among the 9 products. This study can provide a scientific reference for the hydrologic study of the Han River and the management of the Middle Route of the South-to-North Water Transfer Project.
2018, 16(3):10-17.
Abstract:
Inland river plays an important role in the social and economic development and regional water resources utilization in semi-arid plateau areas of China. To recognize and simulate its evolution characteristics is very significant for the basin's sustainable development. In this paper, Balag erriver basin was selected as the study object . Based on the hydrological, meteorological, and socio-economic data in 1959-2015, we analyzed the characteristics of the runoff series by the double mass curve method, the cumulative departure method, the improved M-K trend test, and the wavelet transform method. We used statistical correlation test to select the main input factors for runoff evolution simulation, and realized the simulation of annual and seasonal runoff series evolution by BP artificial net work. The results showed that the runoff decreased significantly at the annual and seasonal scale. The abrupt change of runoff occurred in 1998, before which the runoff was mainly influenced by climate change, while after which by both human activities and climate change. There was a 6-year period and a 30-year period for the annual and dryseason runoff, yet the wet-season runoff showed no obvious periodic change. The impact factors significantly correlated with runoff included precipitation quantity , wet days, number of precipitation events, evaporation, relative humidity , and all indicators of human activity. The improved BP neural network can well simulate the evolution of runoff in this basin when the distributed hydrological simulation cannot be realized.
Inland river plays an important role in the social and economic development and regional water resources utilization in semi-arid plateau areas of China. To recognize and simulate its evolution characteristics is very significant for the basin's sustainable development. In this paper, Balag erriver basin was selected as the study object . Based on the hydrological, meteorological, and socio-economic data in 1959-2015, we analyzed the characteristics of the runoff series by the double mass curve method, the cumulative departure method, the improved M-K trend test, and the wavelet transform method. We used statistical correlation test to select the main input factors for runoff evolution simulation, and realized the simulation of annual and seasonal runoff series evolution by BP artificial net work. The results showed that the runoff decreased significantly at the annual and seasonal scale. The abrupt change of runoff occurred in 1998, before which the runoff was mainly influenced by climate change, while after which by both human activities and climate change. There was a 6-year period and a 30-year period for the annual and dryseason runoff, yet the wet-season runoff showed no obvious periodic change. The impact factors significantly correlated with runoff included precipitation quantity , wet days, number of precipitation events, evaporation, relative humidity , and all indicators of human activity. The improved BP neural network can well simulate the evolution of runoff in this basin when the distributed hydrological simulation cannot be realized.
2018, 16(3):18-23.
Abstract:
Different spatial interpolation methods have different interpolation accuracy in different regions. In order to determine the spatial distribution of rainfall in Chongqing , we used the precipitation data of 12 meteorological stations in Chongqing from 1960 to 2014, and used the IDW method with a coefficient of 2, 3, and 4, the Ordinary Kriging method, the elevation Co-Kriging method, and the temperature Co-Kriging to analyze the precipitation in terms of different indexes, which were the multi-year average, largest 3-month, and smallest 3-month. The results were validated with RMSE and Nash efficiency coefficients. The results showed that in Chongqing, for the three indexes, the interpolation methods from more accurate to less accurate were the elevation Co-Kriging method, temperature Co-Kriging method, OK, IDW4, IDW3, IDW2. For the IDW method, the larger the co-efficient, the smaller the error. Among the three indexes, using the multi-year average precipitation as the input data could produce a more accurate interpolated result . The temperature CK method had good interpolation accuracy when the precipitation was small or the correlation between precipitation and temperature was strong. In the areas with large surface changes in Chongqing , the Co-Kriging method considering elevation can better reflect the impact of elevation changes on precipitation.
Different spatial interpolation methods have different interpolation accuracy in different regions. In order to determine the spatial distribution of rainfall in Chongqing , we used the precipitation data of 12 meteorological stations in Chongqing from 1960 to 2014, and used the IDW method with a coefficient of 2, 3, and 4, the Ordinary Kriging method, the elevation Co-Kriging method, and the temperature Co-Kriging to analyze the precipitation in terms of different indexes, which were the multi-year average, largest 3-month, and smallest 3-month. The results were validated with RMSE and Nash efficiency coefficients. The results showed that in Chongqing, for the three indexes, the interpolation methods from more accurate to less accurate were the elevation Co-Kriging method, temperature Co-Kriging method, OK, IDW4, IDW3, IDW2. For the IDW method, the larger the co-efficient, the smaller the error. Among the three indexes, using the multi-year average precipitation as the input data could produce a more accurate interpolated result . The temperature CK method had good interpolation accuracy when the precipitation was small or the correlation between precipitation and temperature was strong. In the areas with large surface changes in Chongqing , the Co-Kriging method considering elevation can better reflect the impact of elevation changes on precipitation.
2018, 16(3):24-32.
Abstract:
With the increasing shortage of water resources, the research on water resources carrying capacity has become an important topic in the study of regional sustainable development. In order to reduce the influence of subjective sorting of indexes and to solve the problem of high scoring in results, we proposed an improved catastrophe progression method for the assessment of water resources carrying capacity, and applied it to the lower reaches of the Yangtze River area from 2005-2015. An evaluation index system consisting of seventeen indexes in four aspects ( water supply and demand, ecological, economic, social) has been constructed to evaluate the water resources carrying capacity of Jiangxi, Anhui, Jiangsu, Zhejiang , and Shanghai. The results showed that the improved catastrophe progression met hod could be used to sort the indexes objectively , and the evaluation results were accurate and clearly graded. In terms of time, the water carrying capacity of the five provinces was all on the upward trend, but it decreased significantly in certain years, which coincided with the drought years. In terms of space, the integrated rankings of water resources carrying capacity in 2005-2015 were Zhejiang province> Jiangxi province> Anhui province≈ Jiangsu province> Shanghai. In terms of the element layer, the water supply and demand element fluctuated greatly, the ecological and economic elements were growing steadily , and the social element seldom changed and had the lowest score. So we suggest to enhance the utilization efficiency of water resources, and to strengthen water conservancy construction to improve the capability of disaster response.
With the increasing shortage of water resources, the research on water resources carrying capacity has become an important topic in the study of regional sustainable development. In order to reduce the influence of subjective sorting of indexes and to solve the problem of high scoring in results, we proposed an improved catastrophe progression method for the assessment of water resources carrying capacity, and applied it to the lower reaches of the Yangtze River area from 2005-2015. An evaluation index system consisting of seventeen indexes in four aspects ( water supply and demand, ecological, economic, social) has been constructed to evaluate the water resources carrying capacity of Jiangxi, Anhui, Jiangsu, Zhejiang , and Shanghai. The results showed that the improved catastrophe progression met hod could be used to sort the indexes objectively , and the evaluation results were accurate and clearly graded. In terms of time, the water carrying capacity of the five provinces was all on the upward trend, but it decreased significantly in certain years, which coincided with the drought years. In terms of space, the integrated rankings of water resources carrying capacity in 2005-2015 were Zhejiang province> Jiangxi province> Anhui province≈ Jiangsu province> Shanghai. In terms of the element layer, the water supply and demand element fluctuated greatly, the ecological and economic elements were growing steadily , and the social element seldom changed and had the lowest score. So we suggest to enhance the utilization efficiency of water resources, and to strengthen water conservancy construction to improve the capability of disaster response.
2018, 16(3):33-37.
Abstract:
In view of the serious problem of seasonal river leakage in arid or semi-arid areas of northern China, in order to improve the simulation accuracy of flood routing in the basin, we established a seasonal channel flood routing model which couples the traditional hydrodynamic flood routing model with channel leakage. We used the Horton infiltration model to describe seasonal river infiltration and solved the coupling problem between river channel leakage and flood routing model based on Saint-Venant equations. Then, the model was discretized and solved with the Preissmann four-point partial-node implicit scheme and chasing method, and the FORTRAN calculation program was developed. Finally, the model was tested with measured data of the Dagu River basin. The results indicated that the simulated values of water level and flow process in Shawan and Nancun were consistent with the measured values, and their trends of variation were also consistent. The simulated time for the flood peak to reach the cross-section was basically the same as the actual time. The relative error ranges between the measured value and the simulated value of water inflow and leakage in all the channel segments of the study area were -1.66%-0.36% and -3.09%-3.72% respectively. It can be concluded that this coupled model can satisfy the need of flood for ecasting under the present condition.
In view of the serious problem of seasonal river leakage in arid or semi-arid areas of northern China, in order to improve the simulation accuracy of flood routing in the basin, we established a seasonal channel flood routing model which couples the traditional hydrodynamic flood routing model with channel leakage. We used the Horton infiltration model to describe seasonal river infiltration and solved the coupling problem between river channel leakage and flood routing model based on Saint-Venant equations. Then, the model was discretized and solved with the Preissmann four-point partial-node implicit scheme and chasing method, and the FORTRAN calculation program was developed. Finally, the model was tested with measured data of the Dagu River basin. The results indicated that the simulated values of water level and flow process in Shawan and Nancun were consistent with the measured values, and their trends of variation were also consistent. The simulated time for the flood peak to reach the cross-section was basically the same as the actual time. The relative error ranges between the measured value and the simulated value of water inflow and leakage in all the channel segments of the study area were -1.66%-0.36% and -3.09%-3.72% respectively. It can be concluded that this coupled model can satisfy the need of flood for ecasting under the present condition.
2018, 16(3):38-44.
Abstract:
The analysis of the relationship between annual bankfull discharge and inflow mainly focuses on the quantity of runoff and sediment loadat the annual scale (such as water amount, sediment load, and water-sediment coefficient) . Some researchers may also consider some specific characteristics such as peak discharge. However, few studies focus on the discharge hydrograph. We collected measured data of discharge and cross-sections at Huayuankou Hydrology Station during 1954-2000, and adopted flow duration curve (FDC) to describe the discharge hydrograph. Then, we used improved MOL method to estimate the bankfull discharge at different temporal scales, both annual and real-time. The relationship between the coefficients of FDCs and bankfull depth ( annual and real-time) was investigated. The analysis showed that when the discharge changed dramatically, the bankfull discharge was more likely to change, and so was the morphology of cross-sections. In conclusion, in addition to the quantity of runoff and sediment load, discharge hydrograph may also influence the bankfull discharge ( annual and real-time) .
The analysis of the relationship between annual bankfull discharge and inflow mainly focuses on the quantity of runoff and sediment loadat the annual scale (such as water amount, sediment load, and water-sediment coefficient) . Some researchers may also consider some specific characteristics such as peak discharge. However, few studies focus on the discharge hydrograph. We collected measured data of discharge and cross-sections at Huayuankou Hydrology Station during 1954-2000, and adopted flow duration curve (FDC) to describe the discharge hydrograph. Then, we used improved MOL method to estimate the bankfull discharge at different temporal scales, both annual and real-time. The relationship between the coefficients of FDCs and bankfull depth ( annual and real-time) was investigated. The analysis showed that when the discharge changed dramatically, the bankfull discharge was more likely to change, and so was the morphology of cross-sections. In conclusion, in addition to the quantity of runoff and sediment load, discharge hydrograph may also influence the bankfull discharge ( annual and real-time) .
2018, 16(3):45-50.
Abstract:
In accordance with the Huangzhuang Station's monthly runoff from 1981 to 2008 and the correlativity from 1980 to 2007 among the 74 circulation indexes of each month, the monthly north pacific sea surface temperature field, and the 500hPa geopotential height, we used the stepwise regression method to select the forecast factors and built a GA-SVR Model (Genetic Algorithm Support Vector Regression Model) on the basis of GA ( Genetic Algorithm) , inorder to forecast the monthly runoff from 2009 to 2013. The results showed that the accuracy of the runoff forecast was relatively high: the average relative error in flood season was within 25% ; the yearly runoff amount was within 20% in non-flood season. It was superior to Random Forest and Multiple Regression Model. With the forecast results of the GA-SVR Model as the basis of the probability forecast, we used the Hydrologic Uncertainty Processor (HUP) of the Bayesian Theory to analyze the forecast reliability. The outcome indicated that HUP could not only give a constant-value forecast with relatively high accuracy , but also quantify the forecast reliability in the form of a confidence interval to provide more forecast information.
In accordance with the Huangzhuang Station's monthly runoff from 1981 to 2008 and the correlativity from 1980 to 2007 among the 74 circulation indexes of each month, the monthly north pacific sea surface temperature field, and the 500hPa geopotential height, we used the stepwise regression method to select the forecast factors and built a GA-SVR Model (Genetic Algorithm Support Vector Regression Model) on the basis of GA ( Genetic Algorithm) , inorder to forecast the monthly runoff from 2009 to 2013. The results showed that the accuracy of the runoff forecast was relatively high: the average relative error in flood season was within 25% ; the yearly runoff amount was within 20% in non-flood season. It was superior to Random Forest and Multiple Regression Model. With the forecast results of the GA-SVR Model as the basis of the probability forecast, we used the Hydrologic Uncertainty Processor (HUP) of the Bayesian Theory to analyze the forecast reliability. The outcome indicated that HUP could not only give a constant-value forecast with relatively high accuracy , but also quantify the forecast reliability in the form of a confidence interval to provide more forecast information.
2018, 16(3):51-58.
Abstract:
The flood peak discharge of a cut-off ditch is an important parameter in cut-off ditch design. In this paper, we compared three calculation methods for flood peak discharge o f cut-off ditches based on a project case. We studied the influence of rainfall duration, unit weight of torrential flood, and recurrence interval on flood peak discharge, and analyzed the significance degree of the influence factors. It was found that Method 1(Code for design of soil and water conservation projects) and Method 3(Code for design of outdoor drainage projects) had similar results for the project case and both leaned towards safety. The flood peak discharge wouldg radually decrease with the increase of rainfall duration, with a power function relation between them. The peak discharge would increase with the increase of unit weight of torrential flood, with an exponential function relation between them. The peak discharge showed atrend of logarithmic growth with the increase of recurrence interval. Catchment area had the largest influence on flood peak discharge for Methods 1 and 3, followed by rainfall duration and runoff coefficient, while the influence of recurrence interval on flood peak discharge was the smallest. Catchment area had the largest influence on flood peak discharge for Method 2 ( Technical code on soil and water conservation of development and construction projects) , followed by runoff coefficient and recurrence interval, while the influence of unit weight of torrential flood on flood peak discharge was the smallest for Method 2.
The flood peak discharge of a cut-off ditch is an important parameter in cut-off ditch design. In this paper, we compared three calculation methods for flood peak discharge o f cut-off ditches based on a project case. We studied the influence of rainfall duration, unit weight of torrential flood, and recurrence interval on flood peak discharge, and analyzed the significance degree of the influence factors. It was found that Method 1(Code for design of soil and water conservation projects) and Method 3(Code for design of outdoor drainage projects) had similar results for the project case and both leaned towards safety. The flood peak discharge wouldg radually decrease with the increase of rainfall duration, with a power function relation between them. The peak discharge would increase with the increase of unit weight of torrential flood, with an exponential function relation between them. The peak discharge showed atrend of logarithmic growth with the increase of recurrence interval. Catchment area had the largest influence on flood peak discharge for Methods 1 and 3, followed by rainfall duration and runoff coefficient, while the influence of recurrence interval on flood peak discharge was the smallest. Catchment area had the largest influence on flood peak discharge for Method 2 ( Technical code on soil and water conservation of development and construction projects) , followed by runoff coefficient and recurrence interval, while the influence of unit weight of torrential flood on flood peak discharge was the smallest for Method 2.
2018, 16(3):59-64.
Abstract:
On the basis of the rainfall data from 1951 to 2012, in this paper we analyzed the rainfall evolution trend in a typical water-receiving area of East Route of South-to-North Water Diversion Project. We adopted four methods including the moving average method, Mann-Kendall test method, Run test method, and Spearman rank test. Meanwhile we used Morlet wavelet transform to analyze the periodic variation characteristics. The results showed that the rainfall in the region showed an insignificant decreasing trend from 1951 to 2012 and had a 27-year variation cycle. The results have important guiding significance for flood control, drought resisting , agricultural production, and sustainable water diversion for the East Route of South-to-North Water Diversion Project.
On the basis of the rainfall data from 1951 to 2012, in this paper we analyzed the rainfall evolution trend in a typical water-receiving area of East Route of South-to-North Water Diversion Project. We adopted four methods including the moving average method, Mann-Kendall test method, Run test method, and Spearman rank test. Meanwhile we used Morlet wavelet transform to analyze the periodic variation characteristics. The results showed that the rainfall in the region showed an insignificant decreasing trend from 1951 to 2012 and had a 27-year variation cycle. The results have important guiding significance for flood control, drought resisting , agricultural production, and sustainable water diversion for the East Route of South-to-North Water Diversion Project.
2018, 16(3):65-71.
Abstract:
At present, the methods of annual runoff forecast for Danjiangkou reservoir mainly include physical statistical approach and artificial neural network (ANN) . However, these methods have the disadvantages of low accuracy and low stability. In this paper, we applied the regression support vecto rmachine (SVR) model to the annual runoff forecast for Danjiangkou Reservoir. Considering that the penalty coefficient C, the kernel parameterσ, and the insensitive loss coefficient ε all require a large amount of calculation and it is difficult to obtain their optimal value in the actual assignment process, we added the particle swarm optimization (PSO) algorithm to the SVR model and established a PSO-SVR model to realize the automatic optimization of parameters. The results showed that the PSO-SVR model has higher prediction accuracy compared with the SVR model, and has better stability and reliability than the ANN model. The model has a good application value, and can provide some reference for the development of the operation scheme of the middle route of the South-to-North Water Transfer Project.
At present, the methods of annual runoff forecast for Danjiangkou reservoir mainly include physical statistical approach and artificial neural network (ANN) . However, these methods have the disadvantages of low accuracy and low stability. In this paper, we applied the regression support vecto rmachine (SVR) model to the annual runoff forecast for Danjiangkou Reservoir. Considering that the penalty coefficient C, the kernel parameterσ, and the insensitive loss coefficient ε all require a large amount of calculation and it is difficult to obtain their optimal value in the actual assignment process, we added the particle swarm optimization (PSO) algorithm to the SVR model and established a PSO-SVR model to realize the automatic optimization of parameters. The results showed that the PSO-SVR model has higher prediction accuracy compared with the SVR model, and has better stability and reliability than the ANN model. The model has a good application value, and can provide some reference for the development of the operation scheme of the middle route of the South-to-North Water Transfer Project.
11 Impacts of changes in land use and climate on runoff variation in the upper reaches of Wenyu River
2018, 16(3):72-78.
Abstract:
Land use and climate are two main factors directly influencing catchment hydrology and water resources. The separation of their effects is of great importance for land use planning and water resources management. On the basis of statistical analysis of the change trend of meteorological factors and land use from 1980 to 2014, we assessed the impacts of climate change and land use change on the runoff change in the upper reaches of Wenyu river by combining SWAT model simulation and scenarios designing. Results indicated that the SWAT model is a powerful tool to simulate the effect of environmental change on runoff in the upper reaches of Wenyu River. The correlation coefficient R2 and Nash coefficient Ens were 0.80 and 0.79 respectively during the calibration period, and were 0.77 and 0.74 respectively during the validation period. The rainfall and temperature gradually increased; the forest land and cultivated land decreased gradually; the urban and rural areas increased gradually;and the grassland gradually increased during 1995 to 2005. These changes synthetically affected the runoff and caused the runoff to increase first and then decrease. The contribution rate of climate change to runoff was 100.46% , and the contribution rate of land use change to runoff was 2.09% . The climate change had greater influence on the runoff than the land use change in the upper reaches of Wenyu River during 1980-2014. Therefore, how to cope with climate change is worthy of attention in the water resources management.
Land use and climate are two main factors directly influencing catchment hydrology and water resources. The separation of their effects is of great importance for land use planning and water resources management. On the basis of statistical analysis of the change trend of meteorological factors and land use from 1980 to 2014, we assessed the impacts of climate change and land use change on the runoff change in the upper reaches of Wenyu river by combining SWAT model simulation and scenarios designing. Results indicated that the SWAT model is a powerful tool to simulate the effect of environmental change on runoff in the upper reaches of Wenyu River. The correlation coefficient R2 and Nash coefficient Ens were 0.80 and 0.79 respectively during the calibration period, and were 0.77 and 0.74 respectively during the validation period. The rainfall and temperature gradually increased; the forest land and cultivated land decreased gradually; the urban and rural areas increased gradually;and the grassland gradually increased during 1995 to 2005. These changes synthetically affected the runoff and caused the runoff to increase first and then decrease. The contribution rate of climate change to runoff was 100.46% , and the contribution rate of land use change to runoff was 2.09% . The climate change had greater influence on the runoff than the land use change in the upper reaches of Wenyu River during 1980-2014. Therefore, how to cope with climate change is worthy of attention in the water resources management.
2018, 16(3):79-85.
Abstract:
Many economic, social and ecological problems in arid and semi-arid watersheds can be attributed to the scarcity and mismanagement of water resources. Therefore, it is extremely important to seek effective water resources management methods. In this research, a multi-objective fuzzy credibility programming (MFCP) model was developed for supporting agricultural water resources management. This model can conduct fuzzy optimal selection of the comprehensive benefits of the decision-making variables by quantitatively analyzing the weights of different objectives in agricultural development. It can also deal with fuzzy parameters based on the fuzzy credibility theory. The MFCP model was applied to Minqin County in Wuwei city , Gansu province. An optimization model for water resources was established with economic, ecological, and social benefits as the objectives, with the water and land resources endowment as physical restraints. Results showed that the comprehensive benefits of this region could be optimized by reducing the planting area of corns and sunflowers and increasing the area of melons and vegetables. Compared with the actual situation in 2015, the optimized scheme could save 12.6% water resources and increase economic revenue by 13.8% , while reducing the total planting area by 11.1% .
Many economic, social and ecological problems in arid and semi-arid watersheds can be attributed to the scarcity and mismanagement of water resources. Therefore, it is extremely important to seek effective water resources management methods. In this research, a multi-objective fuzzy credibility programming (MFCP) model was developed for supporting agricultural water resources management. This model can conduct fuzzy optimal selection of the comprehensive benefits of the decision-making variables by quantitatively analyzing the weights of different objectives in agricultural development. It can also deal with fuzzy parameters based on the fuzzy credibility theory. The MFCP model was applied to Minqin County in Wuwei city , Gansu province. An optimization model for water resources was established with economic, ecological, and social benefits as the objectives, with the water and land resources endowment as physical restraints. Results showed that the comprehensive benefits of this region could be optimized by reducing the planting area of corns and sunflowers and increasing the area of melons and vegetables. Compared with the actual situation in 2015, the optimized scheme could save 12.6% water resources and increase economic revenue by 13.8% , while reducing the total planting area by 11.1% .
2018, 16(3):86-93.
Abstract:
In the arid inland basin, groundwater has a great influence on the distribution of vegetation. In the middle reaches of the Golmud River, the distribution of vegetation is also groundwater-dependent. We used the normalized difference vegetation index (NDVI) and field observation data of groundwater depth to study the relationship between vegetation distribution and groundwat erdepth. The results showed that when the groundwater depth was less than 4m, the mean NDVI would decrease with the increase of groundwater depth. When the groundwater depth was greater than 4m but less than 8m, the growth of vegetation was affected and became less sensitive to groundwater. When the groundwater depth was more than 8m, the vegetation cover declined seriously, and was not sensitive to the change of groundwater depth. We consider 8m to be the upper limit of groundwater depth that affects vegetation cover in the study area. The regional ecological environment will be severely affected when the groundwater depth is beyond this limit. Different vegetation types were differently influenced by groundwater: The growth of Myricaria was closely associated with groundwater. For salt meadow reed and Ephedra przewalskii, the relationship between their growth and groundwater was complex probably because of soil salinization. A comparison of the research results of different research areas revealed that due to rainfall, evapotranspiration, hydrogeological conditions, human activities, and other factors, the correlation between vegetation and groundwater varied significantly.
In the arid inland basin, groundwater has a great influence on the distribution of vegetation. In the middle reaches of the Golmud River, the distribution of vegetation is also groundwater-dependent. We used the normalized difference vegetation index (NDVI) and field observation data of groundwater depth to study the relationship between vegetation distribution and groundwat erdepth. The results showed that when the groundwater depth was less than 4m, the mean NDVI would decrease with the increase of groundwater depth. When the groundwater depth was greater than 4m but less than 8m, the growth of vegetation was affected and became less sensitive to groundwater. When the groundwater depth was more than 8m, the vegetation cover declined seriously, and was not sensitive to the change of groundwater depth. We consider 8m to be the upper limit of groundwater depth that affects vegetation cover in the study area. The regional ecological environment will be severely affected when the groundwater depth is beyond this limit. Different vegetation types were differently influenced by groundwater: The growth of Myricaria was closely associated with groundwater. For salt meadow reed and Ephedra przewalskii, the relationship between their growth and groundwater was complex probably because of soil salinization. A comparison of the research results of different research areas revealed that due to rainfall, evapotranspiration, hydrogeological conditions, human activities, and other factors, the correlation between vegetation and groundwater varied significantly.
2018, 16(3):94-101.
Abstract:
The geological formation mechanism of permanent barrier lakes in carbonate areas is rarely studied. Systematic analysis is also lacking on the environmental effects of such barrier lakes in arid areas. Their geological fo rmation mechanism has theoretical and practical significance, but the mechanism is not very clearyet. Using detailed field surveys and C14 dating method, we conducted anin-depth study on the formation mechanism and environmental effects of Tianchi Barrier Lake in Wenxian County. The results showed that Tianchi Lake was formed when a strong earthquake struck the Tianchi region (6450±73) years ago, causing two high landslides in the right bank and left bank of Tiachi valley at the sametime, blocking the Tianchi valley . The "inverse grading structure feature" of the landslide deposit causes the particle size structure of the landslide dam material to show the features of"smaller below and larger above" and "smaller in the middle and larger on the sides" . This is the reason why the Tianchi Barrier Lake can stand long, becoming a natural reservoir, forming a unique microclimate, and generating a very rich, varied, and heterogeneous landscape type. The long existence of Tianchi Barrier Lake accelerated the erosion rate down the landslide dam, controlled the undercutting in the lake area, and had little effect on the undercut rate of the valley in the upper reaches of the lake, forming clearly contrasting landforms.
The geological formation mechanism of permanent barrier lakes in carbonate areas is rarely studied. Systematic analysis is also lacking on the environmental effects of such barrier lakes in arid areas. Their geological fo rmation mechanism has theoretical and practical significance, but the mechanism is not very clearyet. Using detailed field surveys and C14 dating method, we conducted anin-depth study on the formation mechanism and environmental effects of Tianchi Barrier Lake in Wenxian County. The results showed that Tianchi Lake was formed when a strong earthquake struck the Tianchi region (6450±73) years ago, causing two high landslides in the right bank and left bank of Tiachi valley at the sametime, blocking the Tianchi valley . The "inverse grading structure feature" of the landslide deposit causes the particle size structure of the landslide dam material to show the features of"smaller below and larger above" and "smaller in the middle and larger on the sides" . This is the reason why the Tianchi Barrier Lake can stand long, becoming a natural reservoir, forming a unique microclimate, and generating a very rich, varied, and heterogeneous landscape type. The long existence of Tianchi Barrier Lake accelerated the erosion rate down the landslide dam, controlled the undercutting in the lake area, and had little effect on the undercut rate of the valley in the upper reaches of the lake, forming clearly contrasting landforms.
2018, 16(3):102-109.
Abstract:
The modern water network construction is intended to solve the problems of water shortage, groundwater overdraft, and ecological deterioration. This paper evaluates the ecological effects of modern water network construction so as to assess the ecological function of modern water network construction. We took Qingzhou City as the research area, and took 2013 as the base year and 2020 and 2025 as the planning years. At 50%, 75% and 95% assurance rates, we conducted optimal allocation and dispatching of water resources through Qingzhou modern water network. According to the allocation and dispatching results, we selected 5 evaluation indexes of ecological effects, and constructed an index system of ecological effects evaluation. Using variable fuzzy evaluation method, we evaluated the ecological effects of the construction of modern water network in Qingzhou. The results showed that the ecological level improved by 1-3 grades after the modern water network was constructed, and the ecological environment was obviously improved. Therefore, the regional modern water network construction and ecological dispatching play an important role in improving the ecological environment.
The modern water network construction is intended to solve the problems of water shortage, groundwater overdraft, and ecological deterioration. This paper evaluates the ecological effects of modern water network construction so as to assess the ecological function of modern water network construction. We took Qingzhou City as the research area, and took 2013 as the base year and 2020 and 2025 as the planning years. At 50%, 75% and 95% assurance rates, we conducted optimal allocation and dispatching of water resources through Qingzhou modern water network. According to the allocation and dispatching results, we selected 5 evaluation indexes of ecological effects, and constructed an index system of ecological effects evaluation. Using variable fuzzy evaluation method, we evaluated the ecological effects of the construction of modern water network in Qingzhou. The results showed that the ecological level improved by 1-3 grades after the modern water network was constructed, and the ecological environment was obviously improved. Therefore, the regional modern water network construction and ecological dispatching play an important role in improving the ecological environment.
2018, 16(3):110-117.
Abstract:
In order to control the tot al amount of non-point source pollution, it is necessary to make a reasonable assessment of the potential of emission reduction. The quantification of emission reduction potential is based on the optimization of emission reduction measures and the development of a feasible emission reduction plan with consideration to both environmental benefits and economic cost. In this study , we took Changzhou City as an example to analyze the emission reduction potential of non-point source pollution. Weco nducted multi-objective optimization of the emission reduction schemes by using the analytic hierarchy process (AHP) , which can carry out quantitative and qualitative analysis at the same time. With the technical feasibility, economic rationality and operability as guidelines, we took total nitrogen reduction rate, total phsphorus reduction rate, ammonia reduction rate, COD reduction rate as environmental indexes, and construction costs and operating costs as economic indexes. We selected alternative emission reduction measures from the demonstration projects and pilot projects in Changzhou and its surrounding areas to ensure their operability . With 2014 as the base year, we estimated the total amount of non-point source pollution in Changzhou using the pollution coefficient method and calculated the reductions according to the optimization measures, and thus we analyzed the emission reduction potential of each pollutant index . We put forward a list of emission reduction measures suitable for non-point source pollution in Changzhou, and used the analytic hierarchy process to optimize the emission reduction measures, and determined the emission reduction potential of non-point source pollution in Changzhou in 2014 with consideration to both environmental benefits and economic costs.
In order to control the tot al amount of non-point source pollution, it is necessary to make a reasonable assessment of the potential of emission reduction. The quantification of emission reduction potential is based on the optimization of emission reduction measures and the development of a feasible emission reduction plan with consideration to both environmental benefits and economic cost. In this study , we took Changzhou City as an example to analyze the emission reduction potential of non-point source pollution. Weco nducted multi-objective optimization of the emission reduction schemes by using the analytic hierarchy process (AHP) , which can carry out quantitative and qualitative analysis at the same time. With the technical feasibility, economic rationality and operability as guidelines, we took total nitrogen reduction rate, total phsphorus reduction rate, ammonia reduction rate, COD reduction rate as environmental indexes, and construction costs and operating costs as economic indexes. We selected alternative emission reduction measures from the demonstration projects and pilot projects in Changzhou and its surrounding areas to ensure their operability . With 2014 as the base year, we estimated the total amount of non-point source pollution in Changzhou using the pollution coefficient method and calculated the reductions according to the optimization measures, and thus we analyzed the emission reduction potential of each pollutant index . We put forward a list of emission reduction measures suitable for non-point source pollution in Changzhou, and used the analytic hierarchy process to optimize the emission reduction measures, and determined the emission reduction potential of non-point source pollution in Changzhou in 2014 with consideration to both environmental benefits and economic costs.
2018, 16(3):118-124.
Abstract:
In this paper, we investigated the water quality , fish, and riparian zone in Dawen River Basin in October 2016 using comprehensive contamination index method, index of biotic integrity for fish, and analytic hierarchy process in order to assess the river ecosystem health in the basin. The results indicated that the health status of the water ecosystem in Dawen River Basin was generally poor. The poor and very poor sites respectively accounted for 50% and 41.7% of the total sampling points, and the sampling points with medium health level only accounted for 8.3% . The water quality was the worst in the south tributary of Dawen River, the southern section of Yingwen River, and the tributaries of Hui River, belonging to the Class Vbad water. In the evaluation of fish integrity, the results showed that 1site was healthy, 10 sites were sub-healthy , and 13 sites were medium, which respectively accounted for 4.2% , 42.6% , and 53.2% of the total sampling points. The riparian zone evaluation showed generally good results.
In this paper, we investigated the water quality , fish, and riparian zone in Dawen River Basin in October 2016 using comprehensive contamination index method, index of biotic integrity for fish, and analytic hierarchy process in order to assess the river ecosystem health in the basin. The results indicated that the health status of the water ecosystem in Dawen River Basin was generally poor. The poor and very poor sites respectively accounted for 50% and 41.7% of the total sampling points, and the sampling points with medium health level only accounted for 8.3% . The water quality was the worst in the south tributary of Dawen River, the southern section of Yingwen River, and the tributaries of Hui River, belonging to the Class Vbad water. In the evaluation of fish integrity, the results showed that 1site was healthy, 10 sites were sub-healthy , and 13 sites were medium, which respectively accounted for 4.2% , 42.6% , and 53.2% of the total sampling points. The riparian zone evaluation showed generally good results.
2018, 16(3):125-134.
Abstract:
Based on the climatic data of 22 meteorological stations in Beijing-Tianjin-Hebei region from 1961 to 2015, by means of the climate tendency rate, Mann-Kendall mutation test, Morlet wavelet analysis, and inverse distance weighting (IDW) , we systematically studied the temporal-spatial variations of climatic variables over the Beijing-Tianjin-Hebei region in the recent 55 years. The results showed that: 1) In the past 55 years, the Beijing-Tianjin-Hebei region underwent an increase of temperature and a decrease of sunshine, precipitation, wind speed, and average relative humidity. 2) The climatic variables all went through a sudden change in 1979-1989, and the annual precipitation went through a second sudden change in 1996. 3) The climatic variables all showed a complex characteristic of coupling at multiple time scales, and their first main period scales ranged from 8 to 25 years. 4) In Beijing-Tianjin-Hebei region, the average air temperature showed a decreasing trend from south to north, with the change rate peaking in the central and western area. Both precipitation and its change rate showed a decreasing trend from east to west. Sunshine hours showed an increasing trend from south to north, while its change rate showed the opposite trend. Relative humidity showed a decreasing trend from southeast to northwest, while its change rate showed a decreasing trend from southwest to northeast. The peaks of wind speed and its change rate both appeared in Zhangbei and Tanggu area.
Based on the climatic data of 22 meteorological stations in Beijing-Tianjin-Hebei region from 1961 to 2015, by means of the climate tendency rate, Mann-Kendall mutation test, Morlet wavelet analysis, and inverse distance weighting (IDW) , we systematically studied the temporal-spatial variations of climatic variables over the Beijing-Tianjin-Hebei region in the recent 55 years. The results showed that: 1) In the past 55 years, the Beijing-Tianjin-Hebei region underwent an increase of temperature and a decrease of sunshine, precipitation, wind speed, and average relative humidity. 2) The climatic variables all went through a sudden change in 1979-1989, and the annual precipitation went through a second sudden change in 1996. 3) The climatic variables all showed a complex characteristic of coupling at multiple time scales, and their first main period scales ranged from 8 to 25 years. 4) In Beijing-Tianjin-Hebei region, the average air temperature showed a decreasing trend from south to north, with the change rate peaking in the central and western area. Both precipitation and its change rate showed a decreasing trend from east to west. Sunshine hours showed an increasing trend from south to north, while its change rate showed the opposite trend. Relative humidity showed a decreasing trend from southeast to northwest, while its change rate showed a decreasing trend from southwest to northeast. The peaks of wind speed and its change rate both appeared in Zhangbei and Tanggu area.
2018, 16(3):135-142.
Abstract:
This paper analyzed the characteristics of joint optimal scheduling system of cascade sluice stations in plain slope water area, and probed the reasonable joint optimization scheduling method, with a view to achieving the best social, economic, and ecological environmental benefits, and to providing a reference for the study of the joint optimal scheduling of a specific area and the formulation and implementation of the development plan of this area. We established a multi-objective joint optimal scheduling model for cascade sluice stations, and used NSGA-ò algorithm to obtain a non-inferior solution set, and then used the multi-attribute decision-making for optimum scheme selection. The Yellow River and its southern area in Suqian city were chosen for a case study . The results demonstrated that compared to conventional scheduling , the joint optimal scheduling could reduce the rate of water shortage and improve the water supply capacity of the system by increasing the quantity of water delivery, and meanwhile reduce the waste water, make full use of water resources, and save the cost of water supply. The results proved that the multi-objective optimal joint operation model and solution method of cascade sluice stations in plain slope water area are quite maneuverable and superior, with guiding significance and application value in practical engineering.
This paper analyzed the characteristics of joint optimal scheduling system of cascade sluice stations in plain slope water area, and probed the reasonable joint optimization scheduling method, with a view to achieving the best social, economic, and ecological environmental benefits, and to providing a reference for the study of the joint optimal scheduling of a specific area and the formulation and implementation of the development plan of this area. We established a multi-objective joint optimal scheduling model for cascade sluice stations, and used NSGA-ò algorithm to obtain a non-inferior solution set, and then used the multi-attribute decision-making for optimum scheme selection. The Yellow River and its southern area in Suqian city were chosen for a case study . The results demonstrated that compared to conventional scheduling , the joint optimal scheduling could reduce the rate of water shortage and improve the water supply capacity of the system by increasing the quantity of water delivery, and meanwhile reduce the waste water, make full use of water resources, and save the cost of water supply. The results proved that the multi-objective optimal joint operation model and solution method of cascade sluice stations in plain slope water area are quite maneuverable and superior, with guiding significance and application value in practical engineering.
20 Application of particle swarm optimization in parameter calibration of channel hydrodynamic model
2018, 16(3):143-148.
Abstract:
Parameter estimation has always been one difficulty in channel hydrodynamic model. Based on the traditional method of calibrating model parameters by personal experience, we proposed a method to optimize and correct model parameters based on the Particle Swarm Optimization algorithm, and established an optimization model for parameter correction. Then we coupled the algorithm with the channel hydrodynamic model. We studied the area comprised of the main Huai River and Shiguan River tributary. Using 1D river flood routing model, we compared the roughness coefficient correction method and the traditional empirical estimation method. Results showed that the corrected roughness coefficient was 0.01 larger on average than the experiential roughness coefficient. The roughness in Huai River was slightly larger than the roughness in Shiguan River tributary. The water level hydrograph simulated by the corrected roughness coefficient fit the measured value better than that by the experiential roughness coefficient. Especially , for the main peak period of the flood hydrograph, the simulation accuracy was improved significantly. Thus, the validity of the proposed algorithm was verified. This algorithm provides an effective method for determining the parameters of complex channel hydrodynamic model.
Parameter estimation has always been one difficulty in channel hydrodynamic model. Based on the traditional method of calibrating model parameters by personal experience, we proposed a method to optimize and correct model parameters based on the Particle Swarm Optimization algorithm, and established an optimization model for parameter correction. Then we coupled the algorithm with the channel hydrodynamic model. We studied the area comprised of the main Huai River and Shiguan River tributary. Using 1D river flood routing model, we compared the roughness coefficient correction method and the traditional empirical estimation method. Results showed that the corrected roughness coefficient was 0.01 larger on average than the experiential roughness coefficient. The roughness in Huai River was slightly larger than the roughness in Shiguan River tributary. The water level hydrograph simulated by the corrected roughness coefficient fit the measured value better than that by the experiential roughness coefficient. Especially , for the main peak period of the flood hydrograph, the simulation accuracy was improved significantly. Thus, the validity of the proposed algorithm was verified. This algorithm provides an effective method for determining the parameters of complex channel hydrodynamic model.
2018, 16(3):149-154.
Abstract:
In view of the upstream slope protection type change in the process of the reinfor cement of dangerous reservoirs, we conducted a physical model test to study the wave run-up and overt opping sit uation of the dry masonry slope protection type and the concrete type, and det ermined the effect of slope protection type change on the wave run-up and crest elevation. In this paper, we took a reservoir dam for a case study. A wave physical model test of a typical section of the slope protection types was carried out at the scale of 1：15. The test results showed that the roughness coeff icients of the dry masonry and concrete types differed by 0.15. After the change of slope protection type from dry masonry to concrete, the calculation value of the maximum wave run-up increased by 0.56 m, and the test value increased by 0.6 m. In this condition, the original crest elevation could not meet the standard requirements. In addition, after the change of slope protection, the wave overtopping will also increase. The maximum wave pressure on the parapet will increase from 15.9 kPa to 17.8 kPa. The results of the test can provide a reference to the design of similar reinfor cement projects.
In view of the upstream slope protection type change in the process of the reinfor cement of dangerous reservoirs, we conducted a physical model test to study the wave run-up and overt opping sit uation of the dry masonry slope protection type and the concrete type, and det ermined the effect of slope protection type change on the wave run-up and crest elevation. In this paper, we took a reservoir dam for a case study. A wave physical model test of a typical section of the slope protection types was carried out at the scale of 1：15. The test results showed that the roughness coeff icients of the dry masonry and concrete types differed by 0.15. After the change of slope protection type from dry masonry to concrete, the calculation value of the maximum wave run-up increased by 0.56 m, and the test value increased by 0.6 m. In this condition, the original crest elevation could not meet the standard requirements. In addition, after the change of slope protection, the wave overtopping will also increase. The maximum wave pressure on the parapet will increase from 15.9 kPa to 17.8 kPa. The results of the test can provide a reference to the design of similar reinfor cement projects.
2018, 16(3):155-161.
Abstract:
The basic indexes for evaluation of a dam's reinforcement effect include time-efficient indexes and non-time-efficient indexes. The quantification of time-efficient indexes is the key to quantitative evaluation of the reinforcement effect of a dam. Since there is a lack of theory on quantification of time-efficient indexes in the reinforcement evaluation system of dams, in this paper we studied the influence of the change of dam behavior and the change of index level on the evaluation of time-efficient indexes, deduced the formulas for safety degree and grade promotion coefficient on the basis of the dimensionless quantitative time-efficient indexes, and then established a quantitative model of time-efficient indexes. The reinforcement of a reservoir in Jiangxi was taken as an example. We analyzed the changes of the time-efficient evaluation indexes before and after reinforcement, and verified the rationality of the model. The results indicated that the time-efficient indexes can be reasonably evaluated by the proposed quantitative model of time-efficient indexes.
The basic indexes for evaluation of a dam's reinforcement effect include time-efficient indexes and non-time-efficient indexes. The quantification of time-efficient indexes is the key to quantitative evaluation of the reinforcement effect of a dam. Since there is a lack of theory on quantification of time-efficient indexes in the reinforcement evaluation system of dams, in this paper we studied the influence of the change of dam behavior and the change of index level on the evaluation of time-efficient indexes, deduced the formulas for safety degree and grade promotion coefficient on the basis of the dimensionless quantitative time-efficient indexes, and then established a quantitative model of time-efficient indexes. The reinforcement of a reservoir in Jiangxi was taken as an example. We analyzed the changes of the time-efficient evaluation indexes before and after reinforcement, and verified the rationality of the model. The results indicated that the time-efficient indexes can be reasonably evaluated by the proposed quantitative model of time-efficient indexes.
2018, 16(3):162-168.
Abstract:
In order to find out the influence of the change of the radial slope of overflow suspended slab on the flow field of the vortex settling chamber, through physical model tests, we used the particle image flow velocity measurement technique (PIV) to measure the three-dimensional velocities of the vortex settling chamber with the radial slope of suspended slab at 0, 0.087, 0.73, and 0.259. With consideration to the working theory of vortex settling chamber, we compared and analyzed the tangential velocity, radial velocity , vertical velocity, and streamline of each working condition. The results showed that with the increase of the radial slope of the suspended slab, the swirling intensity in the vortex settling chamber increased, the air vortex area increased, the water consumption rate decreased, the probability of sediment particles moving to the interior increased, and the possibility of deposition on the suspended slab decreased. The slope of the suspended slab had a great influence on the strength and formation position of secondary flow in the vortex settling chamber. The secondary flow was the most stable at a slope of 0.173. No secondary flow was formed when the slope was 0.259, which was not conducive to the transport of bottom sediment to the bottom hole of sediment discharge. The results of vertical velocity distribution showed that when the slope was 0.259, the vertical upward velocity of transition zone was small, and there was a minimum chance of sediment silting or overflowing . However, the vertical velocity was smaller than tangential velocity and radial velocity, and the transition zone was very small. The influence of vertical velocity on the deposition and sediment interception rate of suspended slabs was negligible.
In order to find out the influence of the change of the radial slope of overflow suspended slab on the flow field of the vortex settling chamber, through physical model tests, we used the particle image flow velocity measurement technique (PIV) to measure the three-dimensional velocities of the vortex settling chamber with the radial slope of suspended slab at 0, 0.087, 0.73, and 0.259. With consideration to the working theory of vortex settling chamber, we compared and analyzed the tangential velocity, radial velocity , vertical velocity, and streamline of each working condition. The results showed that with the increase of the radial slope of the suspended slab, the swirling intensity in the vortex settling chamber increased, the air vortex area increased, the water consumption rate decreased, the probability of sediment particles moving to the interior increased, and the possibility of deposition on the suspended slab decreased. The slope of the suspended slab had a great influence on the strength and formation position of secondary flow in the vortex settling chamber. The secondary flow was the most stable at a slope of 0.173. No secondary flow was formed when the slope was 0.259, which was not conducive to the transport of bottom sediment to the bottom hole of sediment discharge. The results of vertical velocity distribution showed that when the slope was 0.259, the vertical upward velocity of transition zone was small, and there was a minimum chance of sediment silting or overflowing . However, the vertical velocity was smaller than tangential velocity and radial velocity, and the transition zone was very small. The influence of vertical velocity on the deposition and sediment interception rate of suspended slabs was negligible.
2018, 16(3):169-174.
Abstract:
With the rectangular artificially roughened channel as the research object, we established a prediction model of roughness coefficient using the principal component analysis-support vector machine method. According to the preliminary experimental results, we selected four main influence factors: Froude number Fr, absolute roughness△, channel average water depth h, and bottom slope i. We used the principal component analysis method to obtain two main components, and obtained the comprehensive indexes influencing roughness coefficient, and used them for data training , testing, and prediction of the support vector machine. The research results showed that the RMSE and prediction correlation coefficient R of the training setwere 3.85×10﹣4 and 0.997 respectively, while those of the test set were and 0.992 respectively. The relative error was less than 5% . The results showed that the model based on principal component analysis-support vector machine is suitable for predicting the roughness coefficient of artificial channels.
With the rectangular artificially roughened channel as the research object, we established a prediction model of roughness coefficient using the principal component analysis-support vector machine method. According to the preliminary experimental results, we selected four main influence factors: Froude number Fr, absolute roughness△, channel average water depth h, and bottom slope i. We used the principal component analysis method to obtain two main components, and obtained the comprehensive indexes influencing roughness coefficient, and used them for data training , testing, and prediction of the support vector machine. The research results showed that the RMSE and prediction correlation coefficient R of the training setwere 3.85×10﹣4 and 0.997 respectively, while those of the test set were and 0.992 respectively. The relative error was less than 5% . The results showed that the model based on principal component analysis-support vector machine is suitable for predicting the roughness coefficient of artificial channels.
2018, 16(3):175-182.
Abstract:
Because of the imbalance of regional economic and social development and the asynchrony between the construction of supporting projects and that of the main project, there is a mismatch between the initial allocation of water quotas and the actual water demand in the Middle Route Project of South-to-North Water Diversion (SNWD) . Through the water rights trading , the initial water quotas can be reallocated, so as to realize the balance of water supply and demand in the areas along the project and bring out the best comprehensive benefits of the project. The basic conditions of the Middle Route Project of SNWD are complete, so the necessary requirements for water rights trading have been fulfilled. The Ministry of Water Resources and the Henan provincial government jointly launched a pilot project of trans-regional water rights trading of SNWD. Through practical exploration, the pilot project produced good effects and provided important water rights trading experience for other large water diversion projects. Meanw hile, the pilot project also revealed some deep-seated problems which need to be studied and solved in the future. The water rights trading between Pingdingshan and Xinmi has a good guidance and demonstration effect. The market potential of water rights trading in the Middle Route Project of SNWD is huge. By expanding the scale of trading, creating new trading forms and establishing incentive and restraint mechanisms, the government can promote the rapid development of water rights trading.
Because of the imbalance of regional economic and social development and the asynchrony between the construction of supporting projects and that of the main project, there is a mismatch between the initial allocation of water quotas and the actual water demand in the Middle Route Project of South-to-North Water Diversion (SNWD) . Through the water rights trading , the initial water quotas can be reallocated, so as to realize the balance of water supply and demand in the areas along the project and bring out the best comprehensive benefits of the project. The basic conditions of the Middle Route Project of SNWD are complete, so the necessary requirements for water rights trading have been fulfilled. The Ministry of Water Resources and the Henan provincial government jointly launched a pilot project of trans-regional water rights trading of SNWD. Through practical exploration, the pilot project produced good effects and provided important water rights trading experience for other large water diversion projects. Meanw hile, the pilot project also revealed some deep-seated problems which need to be studied and solved in the future. The water rights trading between Pingdingshan and Xinmi has a good guidance and demonstration effect. The market potential of water rights trading in the Middle Route Project of SNWD is huge. By expanding the scale of trading, creating new trading forms and establishing incentive and restraint mechanisms, the government can promote the rapid development of water rights trading.
2018, 16(3):183-188.
Abstract:
Static release experiments were designed to investigate the effect of different chloride concentrations and alkalinity of source water on manganese release in drinking water distribution systems. We sampled pipe scale from the drinking water network of Zhengzhou and prepared experiment water with different concentrations of chloride ( 5mg/L, 23.1mg/L, 60mg/L, 90mg/L) and alkalinity ( 52.5mg/L, 125mg/L, 200mg/L) . A reactor was designed for simulating manganese release. We analyzed the effect of chloride and a lkalinity concentration changes on the manganese release of water pipe scale. The results indicated that the chloride concentration and alkalinity were highly correlated with the manganese release in drinking water network. Chloride was the primary factor affecting the manganese release of water pipe scale. In this experiment, when the concentration of chloride was 30mg/L, with a residence time of 60 hours, the manganese release reached the maximum of 108mg/L, and then the release became steady . Under the condition that the concentration of chloride promoted manganese release, the alkalinity and the manganese release of pipe scale showed an obvious correlation. The results of the experiment can provide a reference for studying manganese release in drinking water distribution systems after water source switching .
Static release experiments were designed to investigate the effect of different chloride concentrations and alkalinity of source water on manganese release in drinking water distribution systems. We sampled pipe scale from the drinking water network of Zhengzhou and prepared experiment water with different concentrations of chloride ( 5mg/L, 23.1mg/L, 60mg/L, 90mg/L) and alkalinity ( 52.5mg/L, 125mg/L, 200mg/L) . A reactor was designed for simulating manganese release. We analyzed the effect of chloride and a lkalinity concentration changes on the manganese release of water pipe scale. The results indicated that the chloride concentration and alkalinity were highly correlated with the manganese release in drinking water network. Chloride was the primary factor affecting the manganese release of water pipe scale. In this experiment, when the concentration of chloride was 30mg/L, with a residence time of 60 hours, the manganese release reached the maximum of 108mg/L, and then the release became steady . Under the condition that the concentration of chloride promoted manganese release, the alkalinity and the manganese release of pipe scale showed an obvious correlation. The results of the experiment can provide a reference for studying manganese release in drinking water distribution systems after water source switching .
2018, 16(3):189-193.
Abstract:
The spatial distribution rules of hydrological variables are often studied in hydrology. The Equivalent Frequency Regional Composition (EFRC) method is an important approach to solving this problem at present. However, there are still some theoretical issues that remain unsolved. Take as an example the composition scheme of "same design frequencies at upstream and downstream, with corresponding value at the interval", we cannot determine which is larger between the frequency of the interval area (C) and the design flood frequency (P) at both upstream and downstream due to a lack of theoretical proof. In this study, we investig ated the relationships between C and P for the normal and Pearson type III ( PE3) distributio ns by means of theo retical deriv at ion and Mo nte Carlo ( MC) ex periment . Results showed that C is lar ger than P for the design flood problem, while for the design problem of runoff or lowflow , P is larger than C. Ther efore, this study has clarified in theory the design frequency of corresponding value at the interval for the EFRC method.
The spatial distribution rules of hydrological variables are often studied in hydrology. The Equivalent Frequency Regional Composition (EFRC) method is an important approach to solving this problem at present. However, there are still some theoretical issues that remain unsolved. Take as an example the composition scheme of "same design frequencies at upstream and downstream, with corresponding value at the interval", we cannot determine which is larger between the frequency of the interval area (C) and the design flood frequency (P) at both upstream and downstream due to a lack of theoretical proof. In this study, we investig ated the relationships between C and P for the normal and Pearson type III ( PE3) distributio ns by means of theo retical deriv at ion and Mo nte Carlo ( MC) ex periment . Results showed that C is lar ger than P for the design flood problem, while for the design problem of runoff or lowflow , P is larger than C. Ther efore, this study has clarified in theory the design frequency of corresponding value at the interval for the EFRC method.
2018, 16(3):194-200.
Abstract:
This paper proposes a method based on data quality evaluation and extraction of water level to improve the steadiness of dat a quality of satellite altimetry in lakes and reservoirs area. We used Jason-3 satellite altimetry data and performed a case study in Hongze Lake area where the altimetric data quality was unsteady. Results showed that the accuracy of this method was obviously better than that of the traditional methods. The correlation coefficient between the satellite-derived water level and the gauged water level increased from 0.11 to 0.59, and the root mean square error was reduced from 2 m to 0.5 m, making the Jason-3 data more reliable for water level monitoring of lakes and reservoirs. In addition, for those periods with poor data quality, since the water level accuracy is gener ally low, they can be discarded based on the results of data quality evaluation. This can further improve the overall monitoring accuracy. The correlation coefficient can be increased to 0.9, and the root mean square error was reduced to 0.19 m. This is of great significance to building a precise capacity curve for the ungauged lakes and reservoirs.
This paper proposes a method based on data quality evaluation and extraction of water level to improve the steadiness of dat a quality of satellite altimetry in lakes and reservoirs area. We used Jason-3 satellite altimetry data and performed a case study in Hongze Lake area where the altimetric data quality was unsteady. Results showed that the accuracy of this method was obviously better than that of the traditional methods. The correlation coefficient between the satellite-derived water level and the gauged water level increased from 0.11 to 0.59, and the root mean square error was reduced from 2 m to 0.5 m, making the Jason-3 data more reliable for water level monitoring of lakes and reservoirs. In addition, for those periods with poor data quality, since the water level accuracy is gener ally low, they can be discarded based on the results of data quality evaluation. This can further improve the overall monitoring accuracy. The correlation coefficient can be increased to 0.9, and the root mean square error was reduced to 0.19 m. This is of great significance to building a precise capacity curve for the ungauged lakes and reservoirs.
2018, 16(3):201-208.
Abstract:
This paper comprehensively interprets the targets of RCS (River Chief System) from four aspects, which are water pollution reduction, water environment improvement, water resources management, and water function improvement. On this basis, it builds the effectiveness evaluation system of RCS in Jiangsu. According to the spatial panel data of cities and districts in Jiangsu Province from 2006 to 2015, this paper systematically analyzes the present situation and regional differences of the implementation of RCS in Jiangsu Province. It is found that during the first decade since the RCS was implemented, its effectiveness has experienced a rapid growth period before 2010, a fluctuating growth period from 2011- 2012, and a rapid development period from 2013 to the present. At the spatial level, the effectiveness of the RCS tends to diminish from southern Jiangsu to middle Jiangsu and to northern Jiangsu. In the recent three years, the growth of effectiveness of RCS in Jiangsu Province is fast in the north and slow in the south, and the spatial difference has gradually narrowed. Finally, the paper puts fo rward the following suggestions: to improve the evaluation system as well as reward and punishment system of the RCS, to strengthen the research and promotion of the technologies of water ecological civilization construction, to promote the RCS in urban and rural areas simultaneo usly, and to make full use of civil forces and capital for water control.
This paper comprehensively interprets the targets of RCS (River Chief System) from four aspects, which are water pollution reduction, water environment improvement, water resources management, and water function improvement. On this basis, it builds the effectiveness evaluation system of RCS in Jiangsu. According to the spatial panel data of cities and districts in Jiangsu Province from 2006 to 2015, this paper systematically analyzes the present situation and regional differences of the implementation of RCS in Jiangsu Province. It is found that during the first decade since the RCS was implemented, its effectiveness has experienced a rapid growth period before 2010, a fluctuating growth period from 2011- 2012, and a rapid development period from 2013 to the present. At the spatial level, the effectiveness of the RCS tends to diminish from southern Jiangsu to middle Jiangsu and to northern Jiangsu. In the recent three years, the growth of effectiveness of RCS in Jiangsu Province is fast in the north and slow in the south, and the spatial difference has gradually narrowed. Finally, the paper puts fo rward the following suggestions: to improve the evaluation system as well as reward and punishment system of the RCS, to strengthen the research and promotion of the technologies of water ecological civilization construction, to promote the RCS in urban and rural areas simultaneo usly, and to make full use of civil forces and capital for water control.
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