Volume 14,Issue 2,2016 Table of Contents
2016, 14(2):1-5.
Abstract:
Flow and Sediment process controlled the formation and evolution of wetlands. They were recognized as the significant driving forces of shaping structure and function of wetland ecosystems. In this paper, the dynamic changes were studied about the area, center of gravity and wetland types of delta wetland, based on the remote sensing data of Yellow River Delta wetland area from 1976 to 2014. The results showed that constructed wetland area had increased 1000 times remarkably. However, natural wetland area had reduced 41.9% with fluctuation during the 40 years. The center of gravity reed, beach-land, culture and salt field wetlands had shifted from northwest to southeast. There were significant difference between south and north of Delta wetland evolution. Northern reed and beach-land area had a decreasing trend. While reed wetland area showed an increasing trend, beach-land area firstly increased, then decreased in southern. The research results may provide a scientific basis for the Yellow River Delta wetland ecosystem’s protection and restoration under the condition of flow and sediment variation.
Flow and Sediment process controlled the formation and evolution of wetlands. They were recognized as the significant driving forces of shaping structure and function of wetland ecosystems. In this paper, the dynamic changes were studied about the area, center of gravity and wetland types of delta wetland, based on the remote sensing data of Yellow River Delta wetland area from 1976 to 2014. The results showed that constructed wetland area had increased 1000 times remarkably. However, natural wetland area had reduced 41.9% with fluctuation during the 40 years. The center of gravity reed, beach-land, culture and salt field wetlands had shifted from northwest to southeast. There were significant difference between south and north of Delta wetland evolution. Northern reed and beach-land area had a decreasing trend. While reed wetland area showed an increasing trend, beach-land area firstly increased, then decreased in southern. The research results may provide a scientific basis for the Yellow River Delta wetland ecosystem’s protection and restoration under the condition of flow and sediment variation.
2016, 14(2):6-10.
Abstract:
As value of ecological water use is reflected by material cycle and energy flow in aquatic ecosystem, ecosystem services value is discussed from the perspective of water cycle, carbon cycle, nitrogen cycle. Ecosystem services value associated water cycle includes climate regulation value, delivery value and water self-purification. Ecosystem services value associated carbon cycle includes net primary productivity and biomass. Ecosystem services value associated nitrogen cycle includes biodiversity protection and water pollution loss. According to the dimensional difference of component parts for ecological water use, emergy method is used to evaluate ecosystem services value. Take Zhengzhou as a case study: its ecological value in 2011 is 3.16×1020sej, and the value from the great to the little is delivery value, climate regulation value, net primary productivity, biodiversity protection, biomass, water self-purification, water pollution loss. At last, the advantages and disadvantages is discussed, and decision-making basis is provided for water ecological recovery.
As value of ecological water use is reflected by material cycle and energy flow in aquatic ecosystem, ecosystem services value is discussed from the perspective of water cycle, carbon cycle, nitrogen cycle. Ecosystem services value associated water cycle includes climate regulation value, delivery value and water self-purification. Ecosystem services value associated carbon cycle includes net primary productivity and biomass. Ecosystem services value associated nitrogen cycle includes biodiversity protection and water pollution loss. According to the dimensional difference of component parts for ecological water use, emergy method is used to evaluate ecosystem services value. Take Zhengzhou as a case study: its ecological value in 2011 is 3.16×1020sej, and the value from the great to the little is delivery value, climate regulation value, net primary productivity, biodiversity protection, biomass, water self-purification, water pollution loss. At last, the advantages and disadvantages is discussed, and decision-making basis is provided for water ecological recovery.
2016, 14(2):11-14.
Abstract:
Water quality assessment is a very ordinary work in the field of water environment, and the evaluation methods generally involve single factor evaluation method and comprehensive evaluation method. However, choosing single factor evaluation method or comprehensive evaluation method to evaluate water quality is something of a dilemma. It is noteworthy that researching how to combine the single factor evaluation method and the comprehensive evaluation method to assess water quality is still given less concern. In order to achieve the above research, this paper learns from the calculation idea of harmony degree equation to put forward a evaluation method of harmony degree equation (HDE) applied to water quality assessment which includes single factor evaluation and comprehensive evaluation. HDE evaluation method not only can replace the comprehensive evaluation method, but also can represent the single factor evaluation method -- that is, it has successfully combined the single factor evaluation method and the comprehensive evaluation method. In this paper, the concrete steps of HDE evaluation method were expounded in detail and cases study was carried out to explain the application process. Research results in this study can expand the application fields of harmony theory, promote the unity of water quality assessment methods and provide reference for other comprehensive assessment.
Water quality assessment is a very ordinary work in the field of water environment, and the evaluation methods generally involve single factor evaluation method and comprehensive evaluation method. However, choosing single factor evaluation method or comprehensive evaluation method to evaluate water quality is something of a dilemma. It is noteworthy that researching how to combine the single factor evaluation method and the comprehensive evaluation method to assess water quality is still given less concern. In order to achieve the above research, this paper learns from the calculation idea of harmony degree equation to put forward a evaluation method of harmony degree equation (HDE) applied to water quality assessment which includes single factor evaluation and comprehensive evaluation. HDE evaluation method not only can replace the comprehensive evaluation method, but also can represent the single factor evaluation method -- that is, it has successfully combined the single factor evaluation method and the comprehensive evaluation method. In this paper, the concrete steps of HDE evaluation method were expounded in detail and cases study was carried out to explain the application process. Research results in this study can expand the application fields of harmony theory, promote the unity of water quality assessment methods and provide reference for other comprehensive assessment.
2016, 14(2):15-20.
Abstract:
In order to study non-point source pollution from corn field under different rainfall levels, a series field experiments were carried out in a corn field plot in the Liao River region, and the loss rules of non-point source pollution from the corn field land under different rainfall levels between wet year of 2013 and normal year of 2014 were analyzed. Results showed that moderate rain events were difficult to form non-point source pollution in the experiment plot with a slope of 0.5‰ when the antecedent rainfall amount was less, but it would form non-point source pollution when the antecedent rainfall was large. The export coefficients of TN, TP and CODCr are 5.46 kg/hm2, 0.57 kg/hm2, 25.79 kg/hm2 in 2013, and in 2014 are 3.14 kg/hm2, 0.27 kg/hm2and 19.62 kg/hm2 respectively, which are higher than those of 2013.
In order to study non-point source pollution from corn field under different rainfall levels, a series field experiments were carried out in a corn field plot in the Liao River region, and the loss rules of non-point source pollution from the corn field land under different rainfall levels between wet year of 2013 and normal year of 2014 were analyzed. Results showed that moderate rain events were difficult to form non-point source pollution in the experiment plot with a slope of 0.5‰ when the antecedent rainfall amount was less, but it would form non-point source pollution when the antecedent rainfall was large. The export coefficients of TN, TP and CODCr are 5.46 kg/hm2, 0.57 kg/hm2, 25.79 kg/hm2 in 2013, and in 2014 are 3.14 kg/hm2, 0.27 kg/hm2and 19.62 kg/hm2 respectively, which are higher than those of 2013.
5 Coordination degree evaluation of city aquatic ecological civilization: the case of Ma’an Shan city
2016, 14(2):21-25.
Abstract:
This study builds up coordination evaluation model based on synergetic theory, establishes “five one” evaluation index system, which includes water security, water ecology, water supply, water management, water culture and view, uses the fuzzy analytic hierarchy process to calculate the weight of each index, and applies the Ma'an Shan city’s aquatic ecological civilization construction as an example to quantitatively evaluated. The result shows coordinating degress of Ma'an Shan city’s aquatic ecological civilization construction is steadily upgrading during 2009~2013, it’s 0.798 in 2013, in the moderate coordination stage.
This study builds up coordination evaluation model based on synergetic theory, establishes “five one” evaluation index system, which includes water security, water ecology, water supply, water management, water culture and view, uses the fuzzy analytic hierarchy process to calculate the weight of each index, and applies the Ma'an Shan city’s aquatic ecological civilization construction as an example to quantitatively evaluated. The result shows coordinating degress of Ma'an Shan city’s aquatic ecological civilization construction is steadily upgrading during 2009~2013, it’s 0.798 in 2013, in the moderate coordination stage.
2016, 14(2):26-31.
Abstract:
The management of urban shallow lakes plays an important role in the urban ecological civilization construction. Using the IKONOS remote sensing image, two artificial neural network models, based on the BP (Back Propagation) and RBF (Radical Basis Function), were set up to inverse the COD, NH3-N, TN and TP quality conditions of the Cihu Lake. The proposed models were also compared with the multivariate linear regression model. The results indicate that the model efficiency of the two ANN models are significantly higher than the multiple linear regression model. The BP model fits the observed data best in the simulation of the NH3-N, TP, while the RBF neural network shows advantages in the simulation of the COD and TN.
The management of urban shallow lakes plays an important role in the urban ecological civilization construction. Using the IKONOS remote sensing image, two artificial neural network models, based on the BP (Back Propagation) and RBF (Radical Basis Function), were set up to inverse the COD, NH3-N, TN and TP quality conditions of the Cihu Lake. The proposed models were also compared with the multivariate linear regression model. The results indicate that the model efficiency of the two ANN models are significantly higher than the multiple linear regression model. The BP model fits the observed data best in the simulation of the NH3-N, TP, while the RBF neural network shows advantages in the simulation of the COD and TN.
2016, 14(2):32-37.
Abstract:
The surface water pollution is a serious problem.To master the water pollution source and control the total amount effectively is the technical base for achieving regulation of water pollution source. It also can provide the necessary technical support for the surface water pollution control.In this paper, the surface water pollution source methods are summarized both in China and abroad. The research and application progress of receptor model which is the more effective source apportionment model technology is discussed in detail,such as ratio method,fingerprint method,chemical mass balance method and multivariate statistical model. The existing problems and application prospect of surface water pollution source analysis technology are reviewed and prospected.It points out that the main problems of current source of water environment analytical technology is: The research objective of source parse pollutants are relatively limited; The lack of complete technical system and the limitations of existing technology limits the rationalization of the source parse result; The incompleting of pollution source component spectrum and the existing monitoring means restrict the deep of source analytical research. It also puts forward that the improvement and optimization for the existing technology as well as the multivariate analysis and coupling application are becoming a source of parsing technology development trend. The geographic information technology, engineering mathematics methods and the development of analysis monitoring technology will write a new page for water environment pollution source analytical research.
The surface water pollution is a serious problem.To master the water pollution source and control the total amount effectively is the technical base for achieving regulation of water pollution source. It also can provide the necessary technical support for the surface water pollution control.In this paper, the surface water pollution source methods are summarized both in China and abroad. The research and application progress of receptor model which is the more effective source apportionment model technology is discussed in detail,such as ratio method,fingerprint method,chemical mass balance method and multivariate statistical model. The existing problems and application prospect of surface water pollution source analysis technology are reviewed and prospected.It points out that the main problems of current source of water environment analytical technology is: The research objective of source parse pollutants are relatively limited; The lack of complete technical system and the limitations of existing technology limits the rationalization of the source parse result; The incompleting of pollution source component spectrum and the existing monitoring means restrict the deep of source analytical research. It also puts forward that the improvement and optimization for the existing technology as well as the multivariate analysis and coupling application are becoming a source of parsing technology development trend. The geographic information technology, engineering mathematics methods and the development of analysis monitoring technology will write a new page for water environment pollution source analytical research.
2016, 14(2):38-43.
Abstract:
Chuanjiang Basin is not only an economic core zone of the Yangtze River upstream, but also an important part of the Country’s Western Development. Changes of land use in valley will contribute to optimize the land use structure, to construct the ecological shelter zone and to protect the habitat of downstream watershed. Based on the land use data in 2000, 2005 and 2013, by using ArcGIS software and other statistical methods, this paper analyzed the characteristics of land use pattern on the space-time dynamic changes in Chuanjiang Basin and made evaluation by the normalized difference vegetation index analysis. The results showed that there were conspicuous differentiation characteristics of the land-use types in spatial scale and component. The land use comprehensive dynamic changes was 0.83 percent, which indicated that 0.83 km2 land per 100 km2 land changed its way of use every year. The multidimensional transformation of land use types was direct manifestation that caused the temporal and spatial distribution changes of land use from 2000 to 2013. Throughout duration of 2000 to 2013, the NDVI was obviously improved, which indicated that the land use changes had certain rationality in the recent 13 years in Chuanjiang basin.
Chuanjiang Basin is not only an economic core zone of the Yangtze River upstream, but also an important part of the Country’s Western Development. Changes of land use in valley will contribute to optimize the land use structure, to construct the ecological shelter zone and to protect the habitat of downstream watershed. Based on the land use data in 2000, 2005 and 2013, by using ArcGIS software and other statistical methods, this paper analyzed the characteristics of land use pattern on the space-time dynamic changes in Chuanjiang Basin and made evaluation by the normalized difference vegetation index analysis. The results showed that there were conspicuous differentiation characteristics of the land-use types in spatial scale and component. The land use comprehensive dynamic changes was 0.83 percent, which indicated that 0.83 km2 land per 100 km2 land changed its way of use every year. The multidimensional transformation of land use types was direct manifestation that caused the temporal and spatial distribution changes of land use from 2000 to 2013. Throughout duration of 2000 to 2013, the NDVI was obviously improved, which indicated that the land use changes had certain rationality in the recent 13 years in Chuanjiang basin.
2016, 14(2):44-48.
Abstract:
To ascertain the influences on soil anti-shearing intensity of different types of crops, this research is aimed at Moyunshan Small Watershed of Liaoning Province. The soil samples of soybean growing area, corn growing area, fruit trees growing area and fruit trees terraces are collected and the soil moisture contents are measured. Soil cohesion and angle of internal friction are measured by direct shearing. It analyses the correlation of soil shear strength and soil moisture between the same crops and the different ones, as well as the internal friction angle. According to the experimental data(soil cohesion: corn(49.27kpa)>soybean(38.36kpa)> terraces(30.00kpa) >fruit tree(28.36kpa); angle of internal fiction: fruit tree(25.45°)>soybean(23.26°)>corn(20.24°)> terraces(19.51°)), the analysis results show that the soil shear strength of corn growing area, soybean growing area, fruit trees growing area and fruit trees terraces has dramatic differences. The quadratic linear analysis of the soil cohesion and soil moisture contents of different types of crops was conducted, and the fitting degree was good.
To ascertain the influences on soil anti-shearing intensity of different types of crops, this research is aimed at Moyunshan Small Watershed of Liaoning Province. The soil samples of soybean growing area, corn growing area, fruit trees growing area and fruit trees terraces are collected and the soil moisture contents are measured. Soil cohesion and angle of internal friction are measured by direct shearing. It analyses the correlation of soil shear strength and soil moisture between the same crops and the different ones, as well as the internal friction angle. According to the experimental data(soil cohesion: corn(49.27kpa)>soybean(38.36kpa)> terraces(30.00kpa) >fruit tree(28.36kpa); angle of internal fiction: fruit tree(25.45°)>soybean(23.26°)>corn(20.24°)> terraces(19.51°)), the analysis results show that the soil shear strength of corn growing area, soybean growing area, fruit trees growing area and fruit trees terraces has dramatic differences. The quadratic linear analysis of the soil cohesion and soil moisture contents of different types of crops was conducted, and the fitting degree was good.
2016, 14(2):49-54.
Abstract:
To discuss the variations in Carbon Di-Oxide emission rate between reed and cotton fields of estuary wetland in temperate zone, we set an experiment to examine the differences of soil respiration rate between cotton community and reed community. The experiment was held in Autumn,10,6,2012. and experiment field lay in Yellow River Delt, the youngest wetland in temperate area. The soil respiration rate was measured by Li-8100 (produced by USA), the data of soil temperature and moisture were also collected by the instrument of Li-8100, atmospheric temperature and relative humidity were monitored synchronously. The results show that the daily changing curves of soil respiratory rate of both cotton community and reed community were asymmetric unimodal, the maximum rate appeared at 12:00-14:00, and the minimum rate took place at 6:00-8:00. However, the mean respiratory rate of the two communities showed great difference, the average respiratory rate of cotton community and reed community were 0.927 μmol?m-2?s-1 and 0.725μmol?m-2?s-1 respectively, this phenomena tells us that cultivated wetland can lead to the increase in carbon emission and contributes to the global warming. The correlation analysis discloses that soil temperature and atmospheric humidity were the main factors influencing soil respiration of the two communities. In detail, soil temperature was the primary environmental factor influencing soil respiration of reed community, and the atmospheric humidity influenced soil respiration of cotton community mainly. The experiment data can be used as the parameters of estuary wetland ecosystem carbon cycle.
To discuss the variations in Carbon Di-Oxide emission rate between reed and cotton fields of estuary wetland in temperate zone, we set an experiment to examine the differences of soil respiration rate between cotton community and reed community. The experiment was held in Autumn,10,6,2012. and experiment field lay in Yellow River Delt, the youngest wetland in temperate area. The soil respiration rate was measured by Li-8100 (produced by USA), the data of soil temperature and moisture were also collected by the instrument of Li-8100, atmospheric temperature and relative humidity were monitored synchronously. The results show that the daily changing curves of soil respiratory rate of both cotton community and reed community were asymmetric unimodal, the maximum rate appeared at 12:00-14:00, and the minimum rate took place at 6:00-8:00. However, the mean respiratory rate of the two communities showed great difference, the average respiratory rate of cotton community and reed community were 0.927 μmol?m-2?s-1 and 0.725μmol?m-2?s-1 respectively, this phenomena tells us that cultivated wetland can lead to the increase in carbon emission and contributes to the global warming. The correlation analysis discloses that soil temperature and atmospheric humidity were the main factors influencing soil respiration of the two communities. In detail, soil temperature was the primary environmental factor influencing soil respiration of reed community, and the atmospheric humidity influenced soil respiration of cotton community mainly. The experiment data can be used as the parameters of estuary wetland ecosystem carbon cycle.
2016, 14(2):55-61.
Abstract:
Using precipitation and temperature for the period of 1851-2008 of Xi'an city, the paper analyzed the variation trends and abrupt changes of hydro-meteorological factors including precipitation and temperature using linear fitting, sliding t test, ordered clustering and Mann-Kendall methods．Firstly, the variation trends of precipitation and temperature were analyzed using linear fitting and anomaly percentage, and then the change characteristic of number of rainy days and precipitation were further analyzed. Finally, the paper investigated the abrupt changes of precipitation and temperature using sliding t test, ordered clustering and Mann-Kendall methods. The results showed that the precipitation decreased gradually. Precipitation accounts for 58% of annual precipitation during the flood season and the annual precipitation distribution is uneven. The annual mean temperature and extreme minimum temperature have increased. The abrupt changes of the precipitation were detected in 1958、1975 and 1980, and the abrupt changes of annual average temperature have found between 1993-1995.
Using precipitation and temperature for the period of 1851-2008 of Xi'an city, the paper analyzed the variation trends and abrupt changes of hydro-meteorological factors including precipitation and temperature using linear fitting, sliding t test, ordered clustering and Mann-Kendall methods．Firstly, the variation trends of precipitation and temperature were analyzed using linear fitting and anomaly percentage, and then the change characteristic of number of rainy days and precipitation were further analyzed. Finally, the paper investigated the abrupt changes of precipitation and temperature using sliding t test, ordered clustering and Mann-Kendall methods. The results showed that the precipitation decreased gradually. Precipitation accounts for 58% of annual precipitation during the flood season and the annual precipitation distribution is uneven. The annual mean temperature and extreme minimum temperature have increased. The abrupt changes of the precipitation were detected in 1958、1975 and 1980, and the abrupt changes of annual average temperature have found between 1993-1995.
2016, 14(2):62-69.
Abstract:
Water scarcity has been a major constraint for both social and economic development in Beijing. When the middle route of the nation’s enormous south-to-north water diversion (SNWD) project begin to supply the water, it is supposed that more than one billion cubic meters of water will be diverted into Beijing annually. This paper focuses on quantitatively evaluating the relative sustainability of Beijing water supply system before and after SNWD project. The four alternative water resources deployment scenarios are considered for the assessment of sustainability in 2020, using the Water Evaluation and Planning System (WEAP) software, the existed water demand and also the supply data of Beijing. The sustainability indices are presented for each scenario, and two of those alternatives are proposed to enhance the sustainability of entire water supply system. Our results showed that the SNWD could significantly contribute to the relief of the water scarcity, and the proposed alternatives will be more beneficial in terms of comprehensive water resources utilization, thus eventually ensure a sustainable water supply in Beijing.
Water scarcity has been a major constraint for both social and economic development in Beijing. When the middle route of the nation’s enormous south-to-north water diversion (SNWD) project begin to supply the water, it is supposed that more than one billion cubic meters of water will be diverted into Beijing annually. This paper focuses on quantitatively evaluating the relative sustainability of Beijing water supply system before and after SNWD project. The four alternative water resources deployment scenarios are considered for the assessment of sustainability in 2020, using the Water Evaluation and Planning System (WEAP) software, the existed water demand and also the supply data of Beijing. The sustainability indices are presented for each scenario, and two of those alternatives are proposed to enhance the sustainability of entire water supply system. Our results showed that the SNWD could significantly contribute to the relief of the water scarcity, and the proposed alternatives will be more beneficial in terms of comprehensive water resources utilization, thus eventually ensure a sustainable water supply in Beijing.
2016, 14(2):70-74.
Abstract:
The study developed a linear fractional two stage programming (FTSP) model for agricultural water management and programming in Zhangweinan River Irrigation Area, China. The developed model incorporated the approaches of two-stage stochastic programming (TSP) and linear fractional programming (LFP) within a general optimization framework, and these uncertainties expressed as both fractional and probability distributions can be addressed. Moreover, the model can reflect tradeoffs between conflicting economic benefits and the associated penalties attributed to the violation of irrigation targets. The results demonstrated that different pre-regulating irrigation target policies lead to different system benefit and target-violation risk, and our optimized scenario balanced the system benefit and irrigation target violating risk; water allocation rate of the two channels are different under different scenarios, and all the fifteen subareas received allocated water flow under high inflow level.
The study developed a linear fractional two stage programming (FTSP) model for agricultural water management and programming in Zhangweinan River Irrigation Area, China. The developed model incorporated the approaches of two-stage stochastic programming (TSP) and linear fractional programming (LFP) within a general optimization framework, and these uncertainties expressed as both fractional and probability distributions can be addressed. Moreover, the model can reflect tradeoffs between conflicting economic benefits and the associated penalties attributed to the violation of irrigation targets. The results demonstrated that different pre-regulating irrigation target policies lead to different system benefit and target-violation risk, and our optimized scenario balanced the system benefit and irrigation target violating risk; water allocation rate of the two channels are different under different scenarios, and all the fifteen subareas received allocated water flow under high inflow level.
2016, 14(2):75-81.
Abstract:
This paper selects five different sources of DEM data—— HydroSHEDS void-filled DEM, SRTM and ASTER GDEM and so on to analyze the quality of different DEM data under different geomorphologic shapes by choosing different geomorphological characteristics analysis method and comparing the simulated drainage networks with the real drainage networks. The result shows that the main problem with ASTER GDEM DEM data is data noise and the other two DEM data both have some fuzzy data. These data quality issues will all effect the accuracy of the data and the river network extracted from them. But in general the accuracy of these digital drainage networks extracted from the three DEM data all have high precision.
This paper selects five different sources of DEM data—— HydroSHEDS void-filled DEM, SRTM and ASTER GDEM and so on to analyze the quality of different DEM data under different geomorphologic shapes by choosing different geomorphological characteristics analysis method and comparing the simulated drainage networks with the real drainage networks. The result shows that the main problem with ASTER GDEM DEM data is data noise and the other two DEM data both have some fuzzy data. These data quality issues will all effect the accuracy of the data and the river network extracted from them. But in general the accuracy of these digital drainage networks extracted from the three DEM data all have high precision.
2016, 14(2):82-86.
Abstract:
Based on the monitoring data from 1964 to 2013 of Sanhe hydrology station, by linear trend method, moving average method, the cumulative anomaly and Morlet wavelet analysis method, explored the discharge variation of Sanhe Sluice for many years. The research results showed that the annual discharge of Sanhe Sluice shows downward trend in recent 50 years; the main period of Sanhe Sluice discharge changes is 30 years, the changes of cycle also exist for 6 years, 14 year time scales. The main period of flood season discharge changes is about 48 years, and 30 years is the second main cycle. There are also some small scales change periods of 5, 10 years. From 30 years of large cycle, the next 8 years the Sanhe Sluice will still at a relatively low water period. It is expected that the discharge begin to enter the relatively abundant water period in 2024, and the wet period will come to end around 2038.
Based on the monitoring data from 1964 to 2013 of Sanhe hydrology station, by linear trend method, moving average method, the cumulative anomaly and Morlet wavelet analysis method, explored the discharge variation of Sanhe Sluice for many years. The research results showed that the annual discharge of Sanhe Sluice shows downward trend in recent 50 years; the main period of Sanhe Sluice discharge changes is 30 years, the changes of cycle also exist for 6 years, 14 year time scales. The main period of flood season discharge changes is about 48 years, and 30 years is the second main cycle. There are also some small scales change periods of 5, 10 years. From 30 years of large cycle, the next 8 years the Sanhe Sluice will still at a relatively low water period. It is expected that the discharge begin to enter the relatively abundant water period in 2024, and the wet period will come to end around 2038.
2016, 14(2):87-92.
Abstract:
Based on the principle of water balance and the hypothesis of linear channel storage, the Muskingum routing model has been in the modifying all the time. In general, the modifying are mainly focused on the differential equation of water balance, the equation of channel storage, and the parameter calibration. On the basis of previous studies, this paper established a modified Muskingum model. In the modified model, the current single period flow was substituted for the combination of historical flows at the same cross section with the combination coefficient of flow. Then, the parameters were calibrated with the Differential Evolution Algorithms. The reach Daheiting Reservoir to Luanxian in Luanhe River was used as a case study. And 10 different flows were selected for simulating and demonstrating the validity of the proposed model and the results suggested the potential improvement in flow simulation.
Based on the principle of water balance and the hypothesis of linear channel storage, the Muskingum routing model has been in the modifying all the time. In general, the modifying are mainly focused on the differential equation of water balance, the equation of channel storage, and the parameter calibration. On the basis of previous studies, this paper established a modified Muskingum model. In the modified model, the current single period flow was substituted for the combination of historical flows at the same cross section with the combination coefficient of flow. Then, the parameters were calibrated with the Differential Evolution Algorithms. The reach Daheiting Reservoir to Luanxian in Luanhe River was used as a case study. And 10 different flows were selected for simulating and demonstrating the validity of the proposed model and the results suggested the potential improvement in flow simulation.
2016, 14(2):93-98.
Abstract:
According to the meteorological date in Xi’an city from 1951 to 2013, the Z index of available rainfall was calculated to propose the characterization of drought strength, which was divided into 7 levels. From the results of analyzing the drought characteristics in city, we find that: (1) Drying appears in spring summer and winter, and every season shows a drying trend according to seasonal difference of drought. (2) The annual Z index shows an increasing trend in 63 years. The frequency and strength of drought have increased remarkably since 1990s. (3) Mann-Kendall test shows that the sudden change years were 1957 and 1958, and drying trend has been existing since the year of 1965 and became more significant since 1997.By comparing with the Palmer index and traditional Z index’ assessments of the typical years’ drought period, the objectivity of the analysis’ results are certified.
According to the meteorological date in Xi’an city from 1951 to 2013, the Z index of available rainfall was calculated to propose the characterization of drought strength, which was divided into 7 levels. From the results of analyzing the drought characteristics in city, we find that: (1) Drying appears in spring summer and winter, and every season shows a drying trend according to seasonal difference of drought. (2) The annual Z index shows an increasing trend in 63 years. The frequency and strength of drought have increased remarkably since 1990s. (3) Mann-Kendall test shows that the sudden change years were 1957 and 1958, and drying trend has been existing since the year of 1965 and became more significant since 1997.By comparing with the Palmer index and traditional Z index’ assessments of the typical years’ drought period, the objectivity of the analysis’ results are certified.
2016, 14(2):99-104.
Abstract:
Attention should be paid on variations and trends of rainfall series before basic flood control and drought relief. By taking the Nanliujiang river basic of Beibu gulf economic region as an example, this paper used wavelet analysis and R/S analysis to research the period characteristics and variation trends of rainfall series. Studies were discussed for flood control scheduling in the range of short period. The results of wavelet analysis and R/S analysis showed that upper reaches of Nanliujiang river had an obvious period about 3 or 8 year, the annual rainfall is tending to decrease in the future; that middle reaches of Nanliujiang river had an obvious period about 3 or 8 year, the annual rainfall is tending to increase in the future; that lower reaches of Nanliujiang river had an obvious period about 5 or 8 year, the annual rainfall is tending to increase in the future. It was concluded that the flood control focuses on the middle and lower reaches of Nanliujiang river, but also need to prevent unexpected rainfall.
Attention should be paid on variations and trends of rainfall series before basic flood control and drought relief. By taking the Nanliujiang river basic of Beibu gulf economic region as an example, this paper used wavelet analysis and R/S analysis to research the period characteristics and variation trends of rainfall series. Studies were discussed for flood control scheduling in the range of short period. The results of wavelet analysis and R/S analysis showed that upper reaches of Nanliujiang river had an obvious period about 3 or 8 year, the annual rainfall is tending to decrease in the future; that middle reaches of Nanliujiang river had an obvious period about 3 or 8 year, the annual rainfall is tending to increase in the future; that lower reaches of Nanliujiang river had an obvious period about 5 or 8 year, the annual rainfall is tending to increase in the future. It was concluded that the flood control focuses on the middle and lower reaches of Nanliujiang river, but also need to prevent unexpected rainfall.
2016, 14(2):105-110.
Abstract:
Research on characteristics of main climate factors in the area such as water, light, heat can contribute to a comprehensive understanding and rational utilization of local climatic resources, which can provide the basis for utilization of water resources, agricultural production planning, and ecological environment monitoring.Based on temperature, precipitation, sunshine duration of Hechi city from 1958 to 2013, the climate change characteristics were analyzed by linear regression, cumulative departure, Mann-Kendall methods.The results showed that: The annual temperature increased remarkably, and the tendency rate was 0. 11℃ /10a, with the mutation point appearing in 1986. The increase of temperature in the four seasons was different, but the biggest increasing range of temperature appeared in summer and autumn, which were the dominant factors of the annual mean temperature rise.The precipitation in spring, summer and autumn and annual precipitation showed a slight decrease tendency, and there was a slight increase of precipitation in winter.The annual sunshine duration was decreasing remarkably with the rate of -63.083 h/10 a, and the mutation point of decrease was in 1970,and there was a remarkable decrease after 1976. The seasonal sunshine duration decreased significantly as well, and the order of four seasons according to decreasing range were summer, autumn, winter and spring.
Research on characteristics of main climate factors in the area such as water, light, heat can contribute to a comprehensive understanding and rational utilization of local climatic resources, which can provide the basis for utilization of water resources, agricultural production planning, and ecological environment monitoring.Based on temperature, precipitation, sunshine duration of Hechi city from 1958 to 2013, the climate change characteristics were analyzed by linear regression, cumulative departure, Mann-Kendall methods.The results showed that: The annual temperature increased remarkably, and the tendency rate was 0. 11℃ /10a, with the mutation point appearing in 1986. The increase of temperature in the four seasons was different, but the biggest increasing range of temperature appeared in summer and autumn, which were the dominant factors of the annual mean temperature rise.The precipitation in spring, summer and autumn and annual precipitation showed a slight decrease tendency, and there was a slight increase of precipitation in winter.The annual sunshine duration was decreasing remarkably with the rate of -63.083 h/10 a, and the mutation point of decrease was in 1970,and there was a remarkable decrease after 1976. The seasonal sunshine duration decreased significantly as well, and the order of four seasons according to decreasing range were summer, autumn, winter and spring.
2016, 14(2):111-117.
Abstract:
Building reservoirs on a river breaks the original balance of flow and sediment. Once the incoming sediment begins to deposit, a siltation will take place in the reservoir area. To slow down the siltation, reservoir flushing is widely used in the reservoir operation. However, reservoir flushing would inevitably waste too much water of a reservoir, damaging the comprehensive benefits of the reservoir. Therefore, the relationship between siltation and benefits must be balanced. As for a certain reservoir, on the condition that the current operation regulations are obeyed, a long-term numerical simulation of flushing process is conducted for different flushing schemes, in which the reasonable ranges of water level and discharge of flushing are proposed, by adopting an one-dimensional non-uniform flow and non-equilibrium sediment transport model, and the multi-year average amount of siltation and electricity generation are calculated to be the indices of the selecting of appropriate flushing schemes. The results indicate that the flushing scheme of a lower water level and a longer duration has a better effect on slowing down the siltation in the reservoir area, with the loss of electricity generation relative small.
Building reservoirs on a river breaks the original balance of flow and sediment. Once the incoming sediment begins to deposit, a siltation will take place in the reservoir area. To slow down the siltation, reservoir flushing is widely used in the reservoir operation. However, reservoir flushing would inevitably waste too much water of a reservoir, damaging the comprehensive benefits of the reservoir. Therefore, the relationship between siltation and benefits must be balanced. As for a certain reservoir, on the condition that the current operation regulations are obeyed, a long-term numerical simulation of flushing process is conducted for different flushing schemes, in which the reasonable ranges of water level and discharge of flushing are proposed, by adopting an one-dimensional non-uniform flow and non-equilibrium sediment transport model, and the multi-year average amount of siltation and electricity generation are calculated to be the indices of the selecting of appropriate flushing schemes. The results indicate that the flushing scheme of a lower water level and a longer duration has a better effect on slowing down the siltation in the reservoir area, with the loss of electricity generation relative small.
2016, 14(2):118-124.
Abstract:
It is o f g reat signif icant to consider soil arching effect for the reasonable ar rang ement and o pt imization desig n of do uble row anti2slide pile. H ow ever ther e are many facto rs affecting soil arching effect, thus the o rthog onal test is used t o study the major and minor relatio ns of the six facto rs that affect t he soil ar ching effect of ant i2slide pile. The six factor s, including pile length, pile spacing , pro per ty parameter s, Po isson's r atio, interface parameters and row spacing , fo rm six factor s with five levels of o rthog onal test desig n, and the finite element analy sis softw are PLAXIS is used to car ry out the numer ical simulation. The re2 sults show that the pile spacing , the Po isson's rat io and row spacing are the majo r factor s o f so il ar ching effect, and pr operty pa2 r ameters, inter face par amet ers and pile leng th ar e the minor factor s. There ex ists coupled effect among these facto rs and the combinat ion of their appr opriate levels w ill be benefit to the so il arching effect.
It is o f g reat signif icant to consider soil arching effect for the reasonable ar rang ement and o pt imization desig n of do uble row anti2slide pile. H ow ever ther e are many facto rs affecting soil arching effect, thus the o rthog onal test is used t o study the major and minor relatio ns of the six facto rs that affect t he soil ar ching effect of ant i2slide pile. The six factor s, including pile length, pile spacing , pro per ty parameter s, Po isson's r atio, interface parameters and row spacing , fo rm six factor s with five levels of o rthog onal test desig n, and the finite element analy sis softw are PLAXIS is used to car ry out the numer ical simulation. The re2 sults show that the pile spacing , the Po isson's rat io and row spacing are the majo r factor s o f so il ar ching effect, and pr operty pa2 r ameters, inter face par amet ers and pile leng th ar e the minor factor s. There ex ists coupled effect among these facto rs and the combinat ion of their appr opriate levels w ill be benefit to the so il arching effect.
2016, 14(2):125-130.
Abstract:
Based on the generalization and analysis of laboratory experimental results 36 groups of cement soil,the influences of various factors (e.g. cement content, curing time, types of cement,curing conditions) on the mechanical properties of unconfined compressive strength of cement are presented.Results show that the unconfined compressive strength of cement soil increases with the growing curing time, and it is deeply affected by the cement content, cement types and curing time, While the effect of curing conditions are greater with a cement content of less than 10%. Moreover it is shown that the stress-strain response with the cement content and curing time of the cement soil. Increasement of curing time and cement content makes the cement soil to be harder and brittler, longer curing time,cement content is greater,the stress-strain relationship curve in the ascent is steep.Finally, change mechanism of the cement soil strength can be seen intuitively from the scanning electron microscope (SEM) test photos with the increasing of cement content.
Based on the generalization and analysis of laboratory experimental results 36 groups of cement soil,the influences of various factors (e.g. cement content, curing time, types of cement,curing conditions) on the mechanical properties of unconfined compressive strength of cement are presented.Results show that the unconfined compressive strength of cement soil increases with the growing curing time, and it is deeply affected by the cement content, cement types and curing time, While the effect of curing conditions are greater with a cement content of less than 10%. Moreover it is shown that the stress-strain response with the cement content and curing time of the cement soil. Increasement of curing time and cement content makes the cement soil to be harder and brittler, longer curing time,cement content is greater,the stress-strain relationship curve in the ascent is steep.Finally, change mechanism of the cement soil strength can be seen intuitively from the scanning electron microscope (SEM) test photos with the increasing of cement content.
2016, 14(2):131-135.
Abstract:
This paper uses a combination treatment of cement, chemical stabilization and mechanical dehydration to stabilize the East Lake sludge. The effect of cement content, curing age and compaction degree on soil engineering properties has been researched by limit moisture test, strength test (including CBR and direct shear test) and permeability test. The results showed that the East Lake sludge stabilized by chemical stabilization and mechanical dehydration is high liquid limit silt with low CBR strength, and cannot meet the requirements of subgrade. Cement can effectively improve the CBR strength and cohesion of the secondary modified cement stabilized soil. Curing age contributes little to CBR strength. Cement content, curing age and compaction degree have little effect on internal friction angle. In addition, permeability coefficient increased at first and then decreased in the process of cement content increasing from 0% to 8%. The cement content is 2% when permeability coefficient reaches the maximum. According to the comprehensive analysis in the process of sludge modified by cement, the cement content should be 8%, and compaction degree should be more than 92% to meet the requirements of subgrade filling.
This paper uses a combination treatment of cement, chemical stabilization and mechanical dehydration to stabilize the East Lake sludge. The effect of cement content, curing age and compaction degree on soil engineering properties has been researched by limit moisture test, strength test (including CBR and direct shear test) and permeability test. The results showed that the East Lake sludge stabilized by chemical stabilization and mechanical dehydration is high liquid limit silt with low CBR strength, and cannot meet the requirements of subgrade. Cement can effectively improve the CBR strength and cohesion of the secondary modified cement stabilized soil. Curing age contributes little to CBR strength. Cement content, curing age and compaction degree have little effect on internal friction angle. In addition, permeability coefficient increased at first and then decreased in the process of cement content increasing from 0% to 8%. The cement content is 2% when permeability coefficient reaches the maximum. According to the comprehensive analysis in the process of sludge modified by cement, the cement content should be 8%, and compaction degree should be more than 92% to meet the requirements of subgrade filling.
2016, 14(2):136-141.
Abstract:
Static and dynamic experiments on saturated remolded samples were performed to study the static and dynamic properties of saturated remolded loess. Analyze the stress-strain curves of saturated remolded loess in the static tests. Based on the results of dynamic triaxial experiments, the relationships among the axial strain, dynamic shear strength, effective stress paths, hysteresis loops and the number of loading cycles were studied. The results show that the axial strain increase gradually with the number of cycles.,and the axial strain curve variation have an inflexion point, under the lower confining pressure, the axial strain increase gently at the beginning then increase suddenly up to the failure of the samples,under the higher confining pressure,the axial strain has a rapid increase at the outset and then the growth of the axial strain becomes slower.at last the axial strain increase sharply again. The effective stress paths move to left gradually with the increase of cycles, and the degrees of movement increase gradually. The effective stress paths of each loading cycle consist of a closed area, and the region increased gradually. With the increase of loading cycles, both the area and inclination of hysteresis loops increase gradually. Through the results from the dynamic elastic modulus tests of saturated remolded loess, 1/Ed increase gradually with the axial strain under the different confining pressure and determine the values of a,b and Edmax from the relationship between 1/Ed and εa. The damping ratio λ increase with the axial strain εa and reach to a stable value. Based on the results the proposed values of λ under the different confining pressures are determined, providing a reference for the engineering practice.
Static and dynamic experiments on saturated remolded samples were performed to study the static and dynamic properties of saturated remolded loess. Analyze the stress-strain curves of saturated remolded loess in the static tests. Based on the results of dynamic triaxial experiments, the relationships among the axial strain, dynamic shear strength, effective stress paths, hysteresis loops and the number of loading cycles were studied. The results show that the axial strain increase gradually with the number of cycles.,and the axial strain curve variation have an inflexion point, under the lower confining pressure, the axial strain increase gently at the beginning then increase suddenly up to the failure of the samples,under the higher confining pressure,the axial strain has a rapid increase at the outset and then the growth of the axial strain becomes slower.at last the axial strain increase sharply again. The effective stress paths move to left gradually with the increase of cycles, and the degrees of movement increase gradually. The effective stress paths of each loading cycle consist of a closed area, and the region increased gradually. With the increase of loading cycles, both the area and inclination of hysteresis loops increase gradually. Through the results from the dynamic elastic modulus tests of saturated remolded loess, 1/Ed increase gradually with the axial strain under the different confining pressure and determine the values of a,b and Edmax from the relationship between 1/Ed and εa. The damping ratio λ increase with the axial strain εa and reach to a stable value. Based on the results the proposed values of λ under the different confining pressures are determined, providing a reference for the engineering practice.
2016, 14(2):142-147.
Abstract:
According to basic theory of genetic algorithm and the characteristics of optimal operation for pumping station, established improved genetic algorithm for solving high-dimensional discrete integer decision variables through improving the control parameter s, crossover mechanism and population. The No.4 Huaian Pumping Station is taken as a study case to compare and analyze the genetic algorithm and improved genetic algorithm applicability to optimal operation for pumping station, which can provide reference for the the design and application of the pumping algorithm. Calculations showed: mix advanced genetic algorithm——FFGA&TPGA, which improved the fitness and population, had high precision, efficiency and uniform convergence. Thus, it had advantages in solving large and complex problems about optimal operation of pumping station.
According to basic theory of genetic algorithm and the characteristics of optimal operation for pumping station, established improved genetic algorithm for solving high-dimensional discrete integer decision variables through improving the control parameter s, crossover mechanism and population. The No.4 Huaian Pumping Station is taken as a study case to compare and analyze the genetic algorithm and improved genetic algorithm applicability to optimal operation for pumping station, which can provide reference for the the design and application of the pumping algorithm. Calculations showed: mix advanced genetic algorithm——FFGA&TPGA, which improved the fitness and population, had high precision, efficiency and uniform convergence. Thus, it had advantages in solving large and complex problems about optimal operation of pumping station.
2016, 14(2):148-151.
Abstract:
In view of mountainous river characteristics， the effect of sediment concentration，flow and diameter to sediment deposition transmission were studied by variable and steep slope flume with single-factor controlling theory in this paper. The results showed that due to the slope becoming gentle ，sediment would be deposited in the middle or lower reach firstly，the higher sediment concentration, the lower flow or the larger diameter was, the faster speed of sediment deposition transmission would be. At the same time, the speed was also related to slope of flume .The steeper the slope was ，the faster the speed would also be.
In view of mountainous river characteristics， the effect of sediment concentration，flow and diameter to sediment deposition transmission were studied by variable and steep slope flume with single-factor controlling theory in this paper. The results showed that due to the slope becoming gentle ，sediment would be deposited in the middle or lower reach firstly，the higher sediment concentration, the lower flow or the larger diameter was, the faster speed of sediment deposition transmission would be. At the same time, the speed was also related to slope of flume .The steeper the slope was ，the faster the speed would also be.
2016, 14(2):152-158.
Abstract:
Based on analysing 407 hydro-chemical data and 139 aquifer rock soil samples date of groundwater fromWei River basin, China, the graphical method, mathematical statistics, Gibbs semi-logarithm diagram and phreeqc simulation method were applied to study the chemical characteristics and formation mechanism of groundwater. According to the principle of division of the groundwater system, the study area can be divided into five secondary groundwater system, namely, Longxi Loess Plateau subsystem, Longdong Loess Plateau subsystem, Shanbei Loess Plateau subsystem, Guanzhong basin Loess Plateau subsystem and Qingling mountains subsystem. The hydro-chemical type of the groundwater in the Wei River basin mainly HCO3-Ca and HCO3-Na, in northern and central there is also distributed HCO3.SO4-Na, HCO3.SO4.Cl-Na, SO4.Cl.HCO3-Na and Cl.SO4-Na type water, most areas groundwater TDS is less than 1g/L of fresh water. the formation of the chemical composition of groundwater were impacted by aquifer mineral dissolution/ precipitation, evaporation concentration and cation exchange.
Based on analysing 407 hydro-chemical data and 139 aquifer rock soil samples date of groundwater fromWei River basin, China, the graphical method, mathematical statistics, Gibbs semi-logarithm diagram and phreeqc simulation method were applied to study the chemical characteristics and formation mechanism of groundwater. According to the principle of division of the groundwater system, the study area can be divided into five secondary groundwater system, namely, Longxi Loess Plateau subsystem, Longdong Loess Plateau subsystem, Shanbei Loess Plateau subsystem, Guanzhong basin Loess Plateau subsystem and Qingling mountains subsystem. The hydro-chemical type of the groundwater in the Wei River basin mainly HCO3-Ca and HCO3-Na, in northern and central there is also distributed HCO3.SO4-Na, HCO3.SO4.Cl-Na, SO4.Cl.HCO3-Na and Cl.SO4-Na type water, most areas groundwater TDS is less than 1g/L of fresh water. the formation of the chemical composition of groundwater were impacted by aquifer mineral dissolution/ precipitation, evaporation concentration and cation exchange.
2016, 14(2):159-164.
Abstract:
Longde county suffered a heavy rain of once every 50 years，resulting in 17 debris flows. Based on the detailed field investigation and geological environmental conditions of this region，the formation conditions of the debris flow were analyzed from 3 aspects as the gradient of gully and slope，material sources and water conditions. The results indicated that the debris flows of Longde county were distributed in the hilly region, where the slope was 20-50°and the height difference was 50-100m. These were favorable geological and geomorphological conditions for debris flow. In the basin the residual soil of orange sandy mudstone of Neogene (Ngn) has the weak dilatability. A certain degree of degradation and softening will occur after immersed by water，resulting in the connection of structure and strength is weakened. Therefore，it was the material source of debris flow. Rainfall was the most important trigger factor of the debris flow. Depending on field investigation and data analysis，the formation of debris flow in Longde county was mainly affected by antecedent precipitation. They belonged to the antecedent precipitation control pattern. So the debris flows in Longde county could be warned by monitoring the antecedent precipitation，especially the indirect antecedent precipitation.
Longde county suffered a heavy rain of once every 50 years，resulting in 17 debris flows. Based on the detailed field investigation and geological environmental conditions of this region，the formation conditions of the debris flow were analyzed from 3 aspects as the gradient of gully and slope，material sources and water conditions. The results indicated that the debris flows of Longde county were distributed in the hilly region, where the slope was 20-50°and the height difference was 50-100m. These were favorable geological and geomorphological conditions for debris flow. In the basin the residual soil of orange sandy mudstone of Neogene (Ngn) has the weak dilatability. A certain degree of degradation and softening will occur after immersed by water，resulting in the connection of structure and strength is weakened. Therefore，it was the material source of debris flow. Rainfall was the most important trigger factor of the debris flow. Depending on field investigation and data analysis，the formation of debris flow in Longde county was mainly affected by antecedent precipitation. They belonged to the antecedent precipitation control pattern. So the debris flows in Longde county could be warned by monitoring the antecedent precipitation，especially the indirect antecedent precipitation.
2016, 14(2):165-171.
Abstract:
Understanding the interaction between surface water and groundwater is of great significance to the establishment of regional water cycle model and water resources evaluation and management. Through the study of isotopic distribution of hydrogen and oxygen in surface water and groundwater of the Dou River basin, the results show that (1) the first aquifer in the riparian zone is recharged by precipitation, irrigation return water, and leakage from surface water; (2) the third aquifer is recharged by leakage from the second aquifer; (3) the second aquifer is also affected by precipitation and irrigation return water; and (4) the fourth aquifer has different isotopic characteristics from other aquifers, and the fourth aquifer in the riparian zone may be recharge by the leakage from the surface water reservoir. The variation of hydraulic connection between groundwater and surface water in the riparian zone is strictly controlled by the groundwater level variation. The groundwater depth at the JingZhuangzi profile is 5 m, and the hydraulic connection between the groundwater and river at the profile behaves naturally with river recharging groundwater during the wet season and groundwater recharging river during the dry season. The groundwater depth reaches up to 25 m at the cross river profile near to the center of the groundwater depression cone, and river recharges groundwater all the time.
Understanding the interaction between surface water and groundwater is of great significance to the establishment of regional water cycle model and water resources evaluation and management. Through the study of isotopic distribution of hydrogen and oxygen in surface water and groundwater of the Dou River basin, the results show that (1) the first aquifer in the riparian zone is recharged by precipitation, irrigation return water, and leakage from surface water; (2) the third aquifer is recharged by leakage from the second aquifer; (3) the second aquifer is also affected by precipitation and irrigation return water; and (4) the fourth aquifer has different isotopic characteristics from other aquifers, and the fourth aquifer in the riparian zone may be recharge by the leakage from the surface water reservoir. The variation of hydraulic connection between groundwater and surface water in the riparian zone is strictly controlled by the groundwater level variation. The groundwater depth at the JingZhuangzi profile is 5 m, and the hydraulic connection between the groundwater and river at the profile behaves naturally with river recharging groundwater during the wet season and groundwater recharging river during the dry season. The groundwater depth reaches up to 25 m at the cross river profile near to the center of the groundwater depression cone, and river recharges groundwater all the time.
2016, 14(2):172-176.
Abstract:
For making reasonable bid-section division scheme of the cluster project, this paper put forward the project cluster fuzzy grey relation analysis and evaluation methods of bid-section division based on the gray theory. Firstly, combining with the characteristics of the cluster project, the relations between each subproject are analyzed and selected, which are the physical space, the construction time, convergence process, construction organization, professional property, supplementary engineering. Secondly, the G1 method is used to determine the weights of the relationship between cluster project sub project, and by using the triangular fuzzy number to quantify the fuzzy relation, the comparison sequence and the reference sequence are selected. Finally, with consideration the impact of the relation weights, according to the fuzzy grey relation analysis, each subproject of weighted fuzzy grey relation degree is calculated to select the optimal bid section division scheme. The research results show that the fuzzy grey relation model of cluster project bid-section division make quantitative analysis on the relationship between each of the sub project, and help to reduce the difficulty of project management, and maximize the advantages of cluster project management.
For making reasonable bid-section division scheme of the cluster project, this paper put forward the project cluster fuzzy grey relation analysis and evaluation methods of bid-section division based on the gray theory. Firstly, combining with the characteristics of the cluster project, the relations between each subproject are analyzed and selected, which are the physical space, the construction time, convergence process, construction organization, professional property, supplementary engineering. Secondly, the G1 method is used to determine the weights of the relationship between cluster project sub project, and by using the triangular fuzzy number to quantify the fuzzy relation, the comparison sequence and the reference sequence are selected. Finally, with consideration the impact of the relation weights, according to the fuzzy grey relation analysis, each subproject of weighted fuzzy grey relation degree is calculated to select the optimal bid section division scheme. The research results show that the fuzzy grey relation model of cluster project bid-section division make quantitative analysis on the relationship between each of the sub project, and help to reduce the difficulty of project management, and maximize the advantages of cluster project management.
2016, 14(2):177-182.
Abstract:
To improve the efficiency of the hydropower project management, this paper proposed entropy-weight and matter-element evaluation model to evaluate the quality of hydropower project construction. On the basis of analyzing the characteristic of the hydropower project construction quality , this paper established evaluation index system. Then, based on the maximum membership degree principle established entropy - weight and matter-element model for hydropower project construction quality. By an example evaluation, confirmed that the evaluation result of the model is consistent with the engineering practice.
To improve the efficiency of the hydropower project management, this paper proposed entropy-weight and matter-element evaluation model to evaluate the quality of hydropower project construction. On the basis of analyzing the characteristic of the hydropower project construction quality , this paper established evaluation index system. Then, based on the maximum membership degree principle established entropy - weight and matter-element model for hydropower project construction quality. By an example evaluation, confirmed that the evaluation result of the model is consistent with the engineering practice.
2016, 14(2):183-186.
Abstract:
Using 3 kinds of different roughness of artificial roughness channel, in 9 different bottom slope, 6 groups of different flow conditions, Studied the relationship between the roughness values and roughness, Froude number of open channel flow. The results show: ①Under the same flow conditions: With the increase of Froude number Fr, the roughness n value increases. Under the same Froude number Fr, The greater the roughness Δ, the greater the roughness value of n . ②Under different absolute roughness :When Fr<0.70, N roughness values with Froude number Fr related, and absolute roughness Δ has little to do, n=f(Fr);When 0.71.1 N roughness values with absolute roughness Δ related, and Froude number Fr has little to do, n=f(Δ).
Using 3 kinds of different roughness of artificial roughness channel, in 9 different bottom slope, 6 groups of different flow conditions, Studied the relationship between the roughness values and roughness, Froude number of open channel flow. The results show: ①Under the same flow conditions: With the increase of Froude number Fr, the roughness n value increases. Under the same Froude number Fr, The greater the roughness Δ, the greater the roughness value of n . ②Under different absolute roughness :When Fr<0.70, N roughness values with Froude number Fr related, and absolute roughness Δ has little to do, n=f(Fr);When 0.7
2016, 14(2):187-192.
Abstract:
To some extent, the flow of dam break in the reservoir can be generalized to collapsed water flow in rectangular column. A mathematical model for dam-break flow under the action of gravity in a rectangular water column has been set up to study the flow characteristics in dam site，moreover，a discharge formula in dam site during the process of dam-break was obtained by dimensional analysis method and the discharge change process in dam site was also analyzed by comparing the different ratio of depth to width. The results showed that the rule of discharge change process in dam site is uniform at the same ratio of depth to width; the peak discharge decreases and the occurring time delay as the ratio of depth to width increases at the different ratio of depth to width, then the discharge formula of peak discharge and occurring time based on the ratio of depth to width is derived and the relationship among peak discharge coefficient, occurring time coefficient in the formula and the ratio of depth to width is also analyzed. The results can provide references for the research of dam-break.
To some extent, the flow of dam break in the reservoir can be generalized to collapsed water flow in rectangular column. A mathematical model for dam-break flow under the action of gravity in a rectangular water column has been set up to study the flow characteristics in dam site，moreover，a discharge formula in dam site during the process of dam-break was obtained by dimensional analysis method and the discharge change process in dam site was also analyzed by comparing the different ratio of depth to width. The results showed that the rule of discharge change process in dam site is uniform at the same ratio of depth to width; the peak discharge decreases and the occurring time delay as the ratio of depth to width increases at the different ratio of depth to width, then the discharge formula of peak discharge and occurring time based on the ratio of depth to width is derived and the relationship among peak discharge coefficient, occurring time coefficient in the formula and the ratio of depth to width is also analyzed. The results can provide references for the research of dam-break.
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