Volume 15,Issue 5,2017 Table of Contents
2017, 15(5):1-8.
Abstract:
Many anabranching reaches in the middle and lower Yangtze River have been experiencing frequent switches of main flow from one channel to another, while the mechanism and influencing factors of the phenomenon are still elusive. To examine how the phenomenon is related to the changes in hydrological process, this study applies rescaled range analysis, Mann-Kendall test and anomaly analysis methods and examines in detail the changes in the time series of annual flow discharge and annual sediment transport rate based on observations from 1951 to 2009 at Jianli hydrological station in the Middle Yangtze River. It is shown that the Hurst exponents of the time series for flow discharge and sediment transport rate take respective values of 0.9430 and 0.9239, implying that both time series have long-memory or persistent characteristics. Man-Kendall detection shows that a significant abrupt change in flow discharge time series occurred in 1967, mainly resulting from river cutoffs taking place upstream, while there is not any significant abrupt change in sediment transport rate time series during the same period. Both rescaled range analysis and Mann-Kendall test methods show that there is no match between the time of each channel switch and variations in the time series of either flow discharge or sediment transport rate. Nevertheless, it is found that when the time series of flow discharge in a flood-dominated regime while the time series of sediment transport rate in a low regime, the right-hand side channel functions as the main channel, while flow discharge in a low regime but sediment transport rate in a high regime, the left-hand side channel serves as the main channel. This demonstrates that it is the matching regimes of flow discharge and sediment transport rate that determines if main flow switches from one channel to the other.
Many anabranching reaches in the middle and lower Yangtze River have been experiencing frequent switches of main flow from one channel to another, while the mechanism and influencing factors of the phenomenon are still elusive. To examine how the phenomenon is related to the changes in hydrological process, this study applies rescaled range analysis, Mann-Kendall test and anomaly analysis methods and examines in detail the changes in the time series of annual flow discharge and annual sediment transport rate based on observations from 1951 to 2009 at Jianli hydrological station in the Middle Yangtze River. It is shown that the Hurst exponents of the time series for flow discharge and sediment transport rate take respective values of 0.9430 and 0.9239, implying that both time series have long-memory or persistent characteristics. Man-Kendall detection shows that a significant abrupt change in flow discharge time series occurred in 1967, mainly resulting from river cutoffs taking place upstream, while there is not any significant abrupt change in sediment transport rate time series during the same period. Both rescaled range analysis and Mann-Kendall test methods show that there is no match between the time of each channel switch and variations in the time series of either flow discharge or sediment transport rate. Nevertheless, it is found that when the time series of flow discharge in a flood-dominated regime while the time series of sediment transport rate in a low regime, the right-hand side channel functions as the main channel, while flow discharge in a low regime but sediment transport rate in a high regime, the left-hand side channel serves as the main channel. This demonstrates that it is the matching regimes of flow discharge and sediment transport rate that determines if main flow switches from one channel to the other.
2017, 15(5):9-14.
Abstract:
Seen from the long time-series of the nature flow into Baiyangdian Lake, it has a rule of the dry season and the wet season alternating. The grey wave forecasting model is applicable to research the rule’s evolutional trend. Using the genetic algorithm (GA) to optimize the first-order grey model（GM（1,1））’s iterative basic value α and background value coefficient β. Taking advantages of GA in efficient convergence and broad select range, basing on the GM(1,1) grey models established the GA-Grey wave forecasting model, thus use it study the trend of the nature flow into Baiyangdian Lake. The final analysis conclusion is that the GA-Grey wave forecasting model is obviously superior to the tradition grey wave forecasting model not only in matching information sequences but also in finding the changing characteristic of the information sequences, thus better forecast the changing of nature flow into Baiyangdian Lake. It shows the feasibility of GA-Grey wave forecasting model, providing the research of the variation of lake water resources quantity a new way.
Seen from the long time-series of the nature flow into Baiyangdian Lake, it has a rule of the dry season and the wet season alternating. The grey wave forecasting model is applicable to research the rule’s evolutional trend. Using the genetic algorithm (GA) to optimize the first-order grey model（GM（1,1））’s iterative basic value α and background value coefficient β. Taking advantages of GA in efficient convergence and broad select range, basing on the GM(1,1) grey models established the GA-Grey wave forecasting model, thus use it study the trend of the nature flow into Baiyangdian Lake. The final analysis conclusion is that the GA-Grey wave forecasting model is obviously superior to the tradition grey wave forecasting model not only in matching information sequences but also in finding the changing characteristic of the information sequences, thus better forecast the changing of nature flow into Baiyangdian Lake. It shows the feasibility of GA-Grey wave forecasting model, providing the research of the variation of lake water resources quantity a new way.
2017, 15(5):15-21.
Abstract:
Based on monthly precipitation and average air temperature data from 86 national meteorological stations during the past 55 years (1960-2014) in the Northeast China, the values of Standardized Precipitation Evapotranspiration Index (SPEI) at various time scales were calculated to represent drought conditions, and the characteristics of spatiotemporal distribution of drought at different time scales in the Northeast China were analyzed. The calculation results were compared with the actual drought area data to verify the applicability of the SPEI to the drought assessment of the Northwest China. The results showed that the frequency of severe droughts in spring, summer, and winter would increase with the increase of the time scale, whereas the frequency of medium droughts would decrease with the increase of the time scale. Droughts and floods in the Northeast China occurred alternatively during the recent 55 years. The frequency and intensity of drought increased gradually on a decadal basis. Generally speaking, the scope of extreme droughts would gradually expand with the increase of the time scale. Droughts occurred at different frequencies in spring, summer, and spring in the Northeast China. No extreme drought occurred in winter in Jilin and Liaoning provinces. No severe drought occurred in the middle of Heilongjiang province.
Based on monthly precipitation and average air temperature data from 86 national meteorological stations during the past 55 years (1960-2014) in the Northeast China, the values of Standardized Precipitation Evapotranspiration Index (SPEI) at various time scales were calculated to represent drought conditions, and the characteristics of spatiotemporal distribution of drought at different time scales in the Northeast China were analyzed. The calculation results were compared with the actual drought area data to verify the applicability of the SPEI to the drought assessment of the Northwest China. The results showed that the frequency of severe droughts in spring, summer, and winter would increase with the increase of the time scale, whereas the frequency of medium droughts would decrease with the increase of the time scale. Droughts and floods in the Northeast China occurred alternatively during the recent 55 years. The frequency and intensity of drought increased gradually on a decadal basis. Generally speaking, the scope of extreme droughts would gradually expand with the increase of the time scale. Droughts occurred at different frequencies in spring, summer, and spring in the Northeast China. No extreme drought occurred in winter in Jilin and Liaoning provinces. No severe drought occurred in the middle of Heilongjiang province.
2017, 15(5):22-28.
Abstract:
This paper introduces a new bankruptcy method for water resource allocation. We analyzed the effectiveness and limitations of the bankruptcy method, and added three new parameters, which were water resource abundance, water use efficiency, and minimum water supply guarantee rate, to the traditional bankruptcy allocation rule to improve this method. When we used these rules in the case study of Dongjang River basin, we found that: the traditional bankruptcy rules could not satisfy the requirements of water allocation; however, the amendatory bankruptcy rule produced more reasonable results, even in the future uncertainty situation. Moreover, the amendatory bankruptcy rule can be adapted to many different requirements through alteration of the weight of each parameter, making it more flexible to be applied to other areas.
This paper introduces a new bankruptcy method for water resource allocation. We analyzed the effectiveness and limitations of the bankruptcy method, and added three new parameters, which were water resource abundance, water use efficiency, and minimum water supply guarantee rate, to the traditional bankruptcy allocation rule to improve this method. When we used these rules in the case study of Dongjang River basin, we found that: the traditional bankruptcy rules could not satisfy the requirements of water allocation; however, the amendatory bankruptcy rule produced more reasonable results, even in the future uncertainty situation. Moreover, the amendatory bankruptcy rule can be adapted to many different requirements through alteration of the weight of each parameter, making it more flexible to be applied to other areas.
2017, 15(5):29-35.
Abstract:
Understanding the impact of climate change on groundwater recharge is considerably vital for the scientific management and evaluation of groundwater resources. This study coupled application of climate generator (ClimGen) with groundwater recharge model (HELP) to assess the groundwater recharge change under 3 assumed future climate scenarios (precipitation decrease 10%, T as temperature increased 2℃, and P&T) in Luancheng Agro-Ecosystem Experimental Station. The results indicated that the furture (2011~2040 yr) mean annual recharge rates in these three scenarios have been decreased by 23.33%, 4.42% and 26.01% respectively compared to the basis (1961~1990 yr), which suggested that the change of potential recharge is dominated by the variation of precipitation. This study was significant for the groundwater resources management and sustainable exploitation in North China Plain.
Understanding the impact of climate change on groundwater recharge is considerably vital for the scientific management and evaluation of groundwater resources. This study coupled application of climate generator (ClimGen) with groundwater recharge model (HELP) to assess the groundwater recharge change under 3 assumed future climate scenarios (precipitation decrease 10%, T as temperature increased 2℃, and P&T) in Luancheng Agro-Ecosystem Experimental Station. The results indicated that the furture (2011~2040 yr) mean annual recharge rates in these three scenarios have been decreased by 23.33%, 4.42% and 26.01% respectively compared to the basis (1961~1990 yr), which suggested that the change of potential recharge is dominated by the variation of precipitation. This study was significant for the groundwater resources management and sustainable exploitation in North China Plain.
2017, 15(5):36-42.
Abstract:
The study on the characteristics of runoff evolution can provide a scientific basis for the development of water resources plans and establishment of hydrological response mechanisms. In this study, the runoff evolution characteristics of Fuyang station were analyzed using M-K test and wavelet analysis based on the discharge data of Fuyang hydrometric station from 1956 to 2011, and the main factors influencing the runoff changes were analyzed from the perspective of climate change and human activities. The results showed that the runoff of Fuyang station of Shayinghe River decreased but the decreasing trend was not significant, not reaching the 95% significance level. An abrupt change occurred around 1966. There was a 13-year periodic variation and a 26-year periodic variation of the runoff, and the periodic evolution process was affected by human activities significantly. As for the driving factors, the contribution rate of human activities to runoff changes was more than 65%. The impact of climate change on runoff changes was relatively weak, and tended to turn from negative to positive.
The study on the characteristics of runoff evolution can provide a scientific basis for the development of water resources plans and establishment of hydrological response mechanisms. In this study, the runoff evolution characteristics of Fuyang station were analyzed using M-K test and wavelet analysis based on the discharge data of Fuyang hydrometric station from 1956 to 2011, and the main factors influencing the runoff changes were analyzed from the perspective of climate change and human activities. The results showed that the runoff of Fuyang station of Shayinghe River decreased but the decreasing trend was not significant, not reaching the 95% significance level. An abrupt change occurred around 1966. There was a 13-year periodic variation and a 26-year periodic variation of the runoff, and the periodic evolution process was affected by human activities significantly. As for the driving factors, the contribution rate of human activities to runoff changes was more than 65%. The impact of climate change on runoff changes was relatively weak, and tended to turn from negative to positive.
2017, 15(5):43-49.
Abstract:
In order to solve the problems of flood overflow, dam break, and back flow of tidal water in river channels in complex conditions, in this paper, we developed a one- and two-dimensional coupled hydrodynamic model to simulate the overflowing and dam-break flood from natural river channels under the joint action of flood and storm surge in a flood-control protection area. Taking into consideration both computational efficiency and precision, we generated grids of different zones, and set a reasonable grid area. According to different vegetation types and surface features, we set different roughness for different zones. We coupled the one-dimensional model of the river channel and the two-dimensional model of the flood-control protection area through the broad-crested weir, used the erosion-based gradual collapse method to simulate the dam-breaking process of the river channel, and realized fine simulation in the complicated situation with flood in the upper reaches of the river and storm surge in the lower reaches. The case study showed that this model can flexibly deal with complicated and volatile hydraulic conditions, and can produce reasonable simulation results. It can provide a powerful basis for the decision-making of flood prevention departments.
In order to solve the problems of flood overflow, dam break, and back flow of tidal water in river channels in complex conditions, in this paper, we developed a one- and two-dimensional coupled hydrodynamic model to simulate the overflowing and dam-break flood from natural river channels under the joint action of flood and storm surge in a flood-control protection area. Taking into consideration both computational efficiency and precision, we generated grids of different zones, and set a reasonable grid area. According to different vegetation types and surface features, we set different roughness for different zones. We coupled the one-dimensional model of the river channel and the two-dimensional model of the flood-control protection area through the broad-crested weir, used the erosion-based gradual collapse method to simulate the dam-breaking process of the river channel, and realized fine simulation in the complicated situation with flood in the upper reaches of the river and storm surge in the lower reaches. The case study showed that this model can flexibly deal with complicated and volatile hydraulic conditions, and can produce reasonable simulation results. It can provide a powerful basis for the decision-making of flood prevention departments.
2017, 15(5):50-55.
Abstract:
The estimation of regional land surface evapotranspiration is of great significance to calculate the total amount of regional water resources and to allocate water resources reasonably. According to the characteristics of the sub river basins controlled by Xueye reservoir, Huangqian reservoir and Dongzhou reservoir in Dawenhe River basin, respectively using MODIS remote sensing method, SWAT model and conversion coefficient of water surface evaporation to estimate the average yearly and monthly land surface evaporation of the three sub basins from 2000 to 2008. Based on the rainfall and natural runoff data of each sub basin over the same period, the estimated results are analyzed and compared. The results show that: in Dawenhe River basin, the accuracy of the MODIS remote sensing method is low; the conversion coefficient method has a certain precision; the SWAT model method has higher calculation precision and better adaptability, and the estimation error is only about 3%. The results provide references for selecting good methods of estimating the land surface evaporation in the semi humid region.
The estimation of regional land surface evapotranspiration is of great significance to calculate the total amount of regional water resources and to allocate water resources reasonably. According to the characteristics of the sub river basins controlled by Xueye reservoir, Huangqian reservoir and Dongzhou reservoir in Dawenhe River basin, respectively using MODIS remote sensing method, SWAT model and conversion coefficient of water surface evaporation to estimate the average yearly and monthly land surface evaporation of the three sub basins from 2000 to 2008. Based on the rainfall and natural runoff data of each sub basin over the same period, the estimated results are analyzed and compared. The results show that: in Dawenhe River basin, the accuracy of the MODIS remote sensing method is low; the conversion coefficient method has a certain precision; the SWAT model method has higher calculation precision and better adaptability, and the estimation error is only about 3%. The results provide references for selecting good methods of estimating the land surface evaporation in the semi humid region.
2017, 15(5):56-62.
Abstract:
Gauged cross section data is used for 1-D hydrodynamic model, and both high resolution DEM and topographic map of 1:10000 is used for 2-D hydrodynamic model. A 1D-2D coupled mathematical model is established to simulate flood routing in Hongze Lake Detention Basin based on Mike Flood. The historical flood data in 2003 and 2007 is used to calibrate and verify the parameters in this model. Calculation of design flood plan(P=1%) is used for model simulation in which design inflow is used for upper boundary of model and Q-H curves of Sanhe Gate, Erhe Gate and Gaoliangjian Gate is used for lower boundary of model. Hongze Lake Detention Basin begins impound when the water level of Jiangba station exceed 14.33m. The dynamic distribution of risk elements in the study area indicates that the model has rationality in simulation. With the increase in flood magnitude, flooded area, flooded duration and other risk factors showed a change of trend. It can be used for flood routing analysis in detention basin.
Gauged cross section data is used for 1-D hydrodynamic model, and both high resolution DEM and topographic map of 1:10000 is used for 2-D hydrodynamic model. A 1D-2D coupled mathematical model is established to simulate flood routing in Hongze Lake Detention Basin based on Mike Flood. The historical flood data in 2003 and 2007 is used to calibrate and verify the parameters in this model. Calculation of design flood plan(P=1%) is used for model simulation in which design inflow is used for upper boundary of model and Q-H curves of Sanhe Gate, Erhe Gate and Gaoliangjian Gate is used for lower boundary of model. Hongze Lake Detention Basin begins impound when the water level of Jiangba station exceed 14.33m. The dynamic distribution of risk elements in the study area indicates that the model has rationality in simulation. With the increase in flood magnitude, flooded area, flooded duration and other risk factors showed a change of trend. It can be used for flood routing analysis in detention basin.
2017, 15(5):63-69.
Abstract:
Based on the measured data of precipitation in Baoji meteorological station from 1961 to 2015, the variation characteristics of precipitation and precipitation forecast were analyzed by using the linear fitting, the ratio coefficient difference curve, the cloud model, and the moving average Markov model. Results showed that the rates of change of the annual precipitation, the precipitation in wet period and the precipitation in dry period were -11.9mm/10a, 2.6mm/10a and -14.5mm/10a, respectively. And the precipitation in dry period decreased significantly. The intra-annual precipitation and inter annual precipitation were very uneven. The degree of uneven distribution of precipitation was a whole year>rainy period>dry period, and the stability of the precipitation inhomogeneity is rainy period>a whole year>dry period. Based on the sum of the forecast value of precipitation in wet and dry season, the error was smaller than the annual scale of precipitation forecast, and the annual precipitation forecast values of 2016-2020 were 613.1mm, 727.0mm, 632.0mm, 457.2mm and 876.7mm, respectively.Research results provided scientific basis for prevention of drought and flood disasters in the region.
Based on the measured data of precipitation in Baoji meteorological station from 1961 to 2015, the variation characteristics of precipitation and precipitation forecast were analyzed by using the linear fitting, the ratio coefficient difference curve, the cloud model, and the moving average Markov model. Results showed that the rates of change of the annual precipitation, the precipitation in wet period and the precipitation in dry period were -11.9mm/10a, 2.6mm/10a and -14.5mm/10a, respectively. And the precipitation in dry period decreased significantly. The intra-annual precipitation and inter annual precipitation were very uneven. The degree of uneven distribution of precipitation was a whole year>rainy period>dry period, and the stability of the precipitation inhomogeneity is rainy period>a whole year>dry period. Based on the sum of the forecast value of precipitation in wet and dry season, the error was smaller than the annual scale of precipitation forecast, and the annual precipitation forecast values of 2016-2020 were 613.1mm, 727.0mm, 632.0mm, 457.2mm and 876.7mm, respectively.Research results provided scientific basis for prevention of drought and flood disasters in the region.
2017, 15(5):70-75.
Abstract:
Industrial water drainage characteristics are an important indicator of undesirable output of industrial water. The analysis of the regional industrial water drainage distribution and its influence factors has important guiding significance to the improvement of regional industrial water utilization efficiency. Based on the first national water survey results in 2011, this paper analyzed the situation of industrial water utilization and drainage in Henan Province, the regional distribution characteristics of industrial drainage quantity, the regional differences in industrial drainage quantity across the major cities in Henan, and its influence factors. In conclusion, most major water consumers and most non-major water consumers in Henan use other drainage methods than drainage into rivers and drainage into pipelines, but most of the sewage water drained by major water consumers is into rivers, and most of the sewage water drained by non-major water consumers is into pipelines. There are also great spatial differences in the industrial water drainage methods and quantity across Henan Province. This is closely related to the differences between the cities in industrial output, water resource abundance, and industrial water consumption. But the industrial structure has little influence on the regional differences in drainage quantity.
Industrial water drainage characteristics are an important indicator of undesirable output of industrial water. The analysis of the regional industrial water drainage distribution and its influence factors has important guiding significance to the improvement of regional industrial water utilization efficiency. Based on the first national water survey results in 2011, this paper analyzed the situation of industrial water utilization and drainage in Henan Province, the regional distribution characteristics of industrial drainage quantity, the regional differences in industrial drainage quantity across the major cities in Henan, and its influence factors. In conclusion, most major water consumers and most non-major water consumers in Henan use other drainage methods than drainage into rivers and drainage into pipelines, but most of the sewage water drained by major water consumers is into rivers, and most of the sewage water drained by non-major water consumers is into pipelines. There are also great spatial differences in the industrial water drainage methods and quantity across Henan Province. This is closely related to the differences between the cities in industrial output, water resource abundance, and industrial water consumption. But the industrial structure has little influence on the regional differences in drainage quantity.
2017, 15(5):76-81.
Abstract:
With the development of society and economy, water for production and domestic use has occupied the water for eco-environmental use for a long period of time, causing a series of ecological environmental problems, such as river blanking, habitat destruction, and ecosystem deterioration. Aiming at these problems and taking fish in the middle reaches of Huai River as the main object of study, we analyzed the natural river flow process, established a conceptual model for fish protection goals based on the goal of ecological restoration of Huai River, used IHA and EFC index system to analyze the characteristics of natural flow variation, and used HEC-RAS model to determine the quantity of flow based on the eco-hydraulic needs of fish. Thus, we obtained the recommended ecological flow which fits the dynamic changes of natural flow and meets the requirements of different levels of habitat goals. The results can provide a basis for scientific and reasonable use of water resources in Huai River basin.
With the development of society and economy, water for production and domestic use has occupied the water for eco-environmental use for a long period of time, causing a series of ecological environmental problems, such as river blanking, habitat destruction, and ecosystem deterioration. Aiming at these problems and taking fish in the middle reaches of Huai River as the main object of study, we analyzed the natural river flow process, established a conceptual model for fish protection goals based on the goal of ecological restoration of Huai River, used IHA and EFC index system to analyze the characteristics of natural flow variation, and used HEC-RAS model to determine the quantity of flow based on the eco-hydraulic needs of fish. Thus, we obtained the recommended ecological flow which fits the dynamic changes of natural flow and meets the requirements of different levels of habitat goals. The results can provide a basis for scientific and reasonable use of water resources in Huai River basin.
2017, 15(5):82-88.
Abstract:
Landfill is currently the primary way to handle the municipal refuse in China. However, the groundwater quality will be deteriorated by landfill leachate, which may become one of the main sources for the current water pollution. In this study, a municipal landfill in Wuhan City was selected to investigate its effects on the adjacent groundwater environment. Groundwater samples were collected from eight boreholes and these samples were analyzed to assess the current groundwater quality in the studied area. The results show that groundwater samples are mainly polluted by Pb, Cd and Fe. The pollutant concentrations increase with the decrease of sampling depth and the decrease of the distances between sampled wells and landfill site. The groundwater pollution impacted by landfill leachate was mainly within a distance of 800 meters and a depth of 5.5 meters. The human health risk assessment was performed to further investigate the potential human health risk exposure to the polluted groundwater in the studied area. The results show that the total risk values of the studied groundwater samples are within a range of 2.71×10-4 a-1 ~ 7.12×10-3 a-1, which is higher than the value recommended by the International Commission on Radiological Protection(ICRP), 5.0×10-5 a-1. The human health risk was mainly induced by exposure to pollutants including Cd, Cr(VI) and nitrate. Cd and nitrate of all the studied groundwater samples were with a potential human health risk higher than 5.0×10-5 a-1 and 50% of the samples were with a potential human health risk, induced by Cr(VI), higher than the recommend ICRP value. In addition, the results show that men's health risk value is generally higher than women exposure to the polluted groundwater.
Landfill is currently the primary way to handle the municipal refuse in China. However, the groundwater quality will be deteriorated by landfill leachate, which may become one of the main sources for the current water pollution. In this study, a municipal landfill in Wuhan City was selected to investigate its effects on the adjacent groundwater environment. Groundwater samples were collected from eight boreholes and these samples were analyzed to assess the current groundwater quality in the studied area. The results show that groundwater samples are mainly polluted by Pb, Cd and Fe. The pollutant concentrations increase with the decrease of sampling depth and the decrease of the distances between sampled wells and landfill site. The groundwater pollution impacted by landfill leachate was mainly within a distance of 800 meters and a depth of 5.5 meters. The human health risk assessment was performed to further investigate the potential human health risk exposure to the polluted groundwater in the studied area. The results show that the total risk values of the studied groundwater samples are within a range of 2.71×10-4 a-1 ~ 7.12×10-3 a-1, which is higher than the value recommended by the International Commission on Radiological Protection(ICRP), 5.0×10-5 a-1. The human health risk was mainly induced by exposure to pollutants including Cd, Cr(VI) and nitrate. Cd and nitrate of all the studied groundwater samples were with a potential human health risk higher than 5.0×10-5 a-1 and 50% of the samples were with a potential human health risk, induced by Cr(VI), higher than the recommend ICRP value. In addition, the results show that men's health risk value is generally higher than women exposure to the polluted groundwater.
2017, 15(5):89-96.
Abstract:
Based on GF-116m resolution multispectral remote sensing satellite and hydrological observation data by calculating Normalized Difference Water Index (NDWI) to extract the surface area of the Danjiangkou Reservoir, and to study the correlations of surface area, water level and volume of water between the three, dynamic analysis reservoir storage capacity changes, in order to provide decision support for the "South-to-North diversion project". The result shows: ①water transfer before and after the first dispatch of Danjiangkou Reservoir water area - water depth, water depth - storage capacity and surface area-storage capacity. there is significant correlation, and three pairs of variables present strong linear, conic, cubic curve relationship in turn, the decisive coefficients of Curve-fitting equations were 0.976, 0.999, 0.980 respectively. It may predict two other unknown variables from one known; ② the maximum range of water area from October 5, 2014 to May 5, 2016 was 180km2, which is an important factor that affects the surrounding environment; ③ Finally, storage capacity at the same time in the first year scheduling, in early November 2014, reached the maximum 20.41 billion m3, adjustable water in 1.653 within the range of floating 7.893 billion m3, and the total change in the year was flat and stable to ensure that the water demand during the 2015 scheduling of the North Water Transfer Project.
Based on GF-116m resolution multispectral remote sensing satellite and hydrological observation data by calculating Normalized Difference Water Index (NDWI) to extract the surface area of the Danjiangkou Reservoir, and to study the correlations of surface area, water level and volume of water between the three, dynamic analysis reservoir storage capacity changes, in order to provide decision support for the "South-to-North diversion project". The result shows: ①water transfer before and after the first dispatch of Danjiangkou Reservoir water area - water depth, water depth - storage capacity and surface area-storage capacity. there is significant correlation, and three pairs of variables present strong linear, conic, cubic curve relationship in turn, the decisive coefficients of Curve-fitting equations were 0.976, 0.999, 0.980 respectively. It may predict two other unknown variables from one known; ② the maximum range of water area from October 5, 2014 to May 5, 2016 was 180km2, which is an important factor that affects the surrounding environment; ③ Finally, storage capacity at the same time in the first year scheduling, in early November 2014, reached the maximum 20.41 billion m3, adjustable water in 1.653 within the range of floating 7.893 billion m3, and the total change in the year was flat and stable to ensure that the water demand during the 2015 scheduling of the North Water Transfer Project.
2017, 15(5):97-103.
Abstract:
The effects of the sinkhole size on the drainage process of fissure-conduit media were analyzed using the self-designed physical model of fissure-conduit media. The media was divided into three regions according to the structural characteristics of the media voids. Water discharge per unit time, a concept that represents the speed of water drainage, was introduced. The water discharges per unit time of the three regions and of the media as a whole were calculated. The water discharge per unit time was used to analyze the effects of nine different sinkhole sizes on the drainage process of the fissure-conduit media. The results showed that as the cross-sectional area of the sinkhole increased, the water storage volume and water conducting volume of the media were enlarged, and the drainage speed was enhanced. It was only when the cross-sectional area reached a certain threshold that the drainage process would respond to the increase in the cross-sectional area of the sinkhole. This threshold depended on the structure of the media voids. The three different stages of the drainage process had different thresholds. The threshold in the final stage was smaller than that in the initial or middle stage.
The effects of the sinkhole size on the drainage process of fissure-conduit media were analyzed using the self-designed physical model of fissure-conduit media. The media was divided into three regions according to the structural characteristics of the media voids. Water discharge per unit time, a concept that represents the speed of water drainage, was introduced. The water discharges per unit time of the three regions and of the media as a whole were calculated. The water discharge per unit time was used to analyze the effects of nine different sinkhole sizes on the drainage process of the fissure-conduit media. The results showed that as the cross-sectional area of the sinkhole increased, the water storage volume and water conducting volume of the media were enlarged, and the drainage speed was enhanced. It was only when the cross-sectional area reached a certain threshold that the drainage process would respond to the increase in the cross-sectional area of the sinkhole. This threshold depended on the structure of the media voids. The three different stages of the drainage process had different thresholds. The threshold in the final stage was smaller than that in the initial or middle stage.
2017, 15(5):104-109.
Abstract:
As weight is an important issue in risk evaluation of debris flow, an optimization algorithm of determining weight reasonably is proposed in this paper based on improved combination weighting matter-element extension model. Firstly, according to references, risk classification standard of debris flow is suggested, and assessment indices of hazard degree are set up. Then, with matter-element extension evaluation idea, in order to get the weight of each indicator of this method, coupling the subjective weight calculated by analytical hierarchy process and the objective weight calculated by projection pursuit method with distance function to get comprehensive weight of indicators, using bat algorithm which is optimized by projection pursuit method to get solution, according to above research, combination weighting matter-element extension model and algorithm of debris flow are built. Finally, programming with Mat lab language to realize this algorithm, compare the results from this algorithm to existing projects, it turns out that the evaluation conclusion is reasonable which has definite value to engineering application.
As weight is an important issue in risk evaluation of debris flow, an optimization algorithm of determining weight reasonably is proposed in this paper based on improved combination weighting matter-element extension model. Firstly, according to references, risk classification standard of debris flow is suggested, and assessment indices of hazard degree are set up. Then, with matter-element extension evaluation idea, in order to get the weight of each indicator of this method, coupling the subjective weight calculated by analytical hierarchy process and the objective weight calculated by projection pursuit method with distance function to get comprehensive weight of indicators, using bat algorithm which is optimized by projection pursuit method to get solution, according to above research, combination weighting matter-element extension model and algorithm of debris flow are built. Finally, programming with Mat lab language to realize this algorithm, compare the results from this algorithm to existing projects, it turns out that the evaluation conclusion is reasonable which has definite value to engineering application.
2017, 15(5):110-115.
Abstract:
The three-dimensional Gapa landslide model is established by using the finite difference software FLAC3D. The El-Centro seismic acceleration history is selected as the dynamic excitation, and it is multiplied by the magnification factors 1 and 3, respectively. The calculation results show that the permanent displacement of slope will occur when the magnification factor equals to 1, but it will not slide; when seismic history is multiplied by 3, the slope will slide. Moreover, the deformation characteristics are different under the seismic excitation with different magnification factor. In the first case deformation mainly concentrated on the sliding body Ⅲ, but in the second case the deformation of sliding body Ⅰ is much more intense. This paper analyzed this phenomenon in three aspects of the parameters of composition material, the topographic factor and the dynamic characteristics of slope. The permanent displacement is calculated by Newmark finite sliding displacement method and the results meet the numerical calculation well. It shows that the sliding body Ⅲ has the greater permanent displacement due to the dynamic characteristics of slope. Also, the permanent displacement can also be used as the index for the effect of earthquake on local deformation to estimate the damage of earthquake.
The three-dimensional Gapa landslide model is established by using the finite difference software FLAC3D. The El-Centro seismic acceleration history is selected as the dynamic excitation, and it is multiplied by the magnification factors 1 and 3, respectively. The calculation results show that the permanent displacement of slope will occur when the magnification factor equals to 1, but it will not slide; when seismic history is multiplied by 3, the slope will slide. Moreover, the deformation characteristics are different under the seismic excitation with different magnification factor. In the first case deformation mainly concentrated on the sliding body Ⅲ, but in the second case the deformation of sliding body Ⅰ is much more intense. This paper analyzed this phenomenon in three aspects of the parameters of composition material, the topographic factor and the dynamic characteristics of slope. The permanent displacement is calculated by Newmark finite sliding displacement method and the results meet the numerical calculation well. It shows that the sliding body Ⅲ has the greater permanent displacement due to the dynamic characteristics of slope. Also, the permanent displacement can also be used as the index for the effect of earthquake on local deformation to estimate the damage of earthquake.
2017, 15(5):116-120.
Abstract:
Based on the analytical solution to well flow problem of unsteady flows in the first type leakage aquifer, the chaotic time-series optimization algorithm is employed to analyze the data of pumpling tests to determine aquifer parameters. Numerical simulation is conducted through analysis of the influence of the initial value of aquifer parameters and other factors on the convergence and results of the algorithm. The results show that:①chaotic time-series optimization algorithm can be effectively applied to the calculation problem of aquifer parameters; ②the initial value of leakage factor and the coefficient of storage and conductivity don’t have too much obvious effect on the search and results of the algorithm，except reduce the accurancy of results of leakage factor due to its initial value. Compared with other methods, the chaotic optimization method has such advantages as simple in principle of algorithm, easy to make program and to conduct, and the precision of aquifer parameters calculated is not affected by artificial subjective factors.
Based on the analytical solution to well flow problem of unsteady flows in the first type leakage aquifer, the chaotic time-series optimization algorithm is employed to analyze the data of pumpling tests to determine aquifer parameters. Numerical simulation is conducted through analysis of the influence of the initial value of aquifer parameters and other factors on the convergence and results of the algorithm. The results show that:①chaotic time-series optimization algorithm can be effectively applied to the calculation problem of aquifer parameters; ②the initial value of leakage factor and the coefficient of storage and conductivity don’t have too much obvious effect on the search and results of the algorithm，except reduce the accurancy of results of leakage factor due to its initial value. Compared with other methods, the chaotic optimization method has such advantages as simple in principle of algorithm, easy to make program and to conduct, and the precision of aquifer parameters calculated is not affected by artificial subjective factors.
2017, 15(5):121-126.
Abstract:
The hydro-chemical composition, Dissolved Inorganic Carbon (DIC), Dissolved Organic Carbon (DOC), Particulate Organic Carbon (POC) and δ13CDIC, δ13CPOC in spring water discharging from loess section in Qiushe village, Dudian town, Lingtai county, Gansu province of Northwestern China were determined, and CO2 consumption of carbonate weathering during rainfall recharge was estimated in this study. The results show that the chemical type of groundwater in study area is HCO3-Ca?Mg type. The Saturation Index of calcite (SIc) in spring water (above 0) displays the springs are saturated, however, the spring hardly appears the phenomenon of massive precipitation. The DIC concentration in groundwater of loess area is 5.25~5.45mmol/L, and the DOC concentration is 0.59 ~ 0.62 mg/L, lower than that in surface water. While POC concentration is high due to the mixture of loess particle matter. The δ13C of DIC in springs and wells ranged from -9.19‰ to -8.90‰. The positive distribution of δ13CDIC may be attributed to the repeated exchange of C isotope during the process of carbonate weathering and precipitation. The δ13CPOC ranged from -19.99‰ ~ -18.87‰, consistent with the isotope ratio of the organic carbon in loess. The HCO3-, Ca2+ and Mg2+ in groundwater mainly derive from the weathering of carbonate in loess. According to the ion balance of carbonate weathering reaction, the CO2 sink by carbonate weathering is calculated up to 2.82mmol/L. In other words, the 2.82mmol CO2 can be absorbed by carbonate weathering when 1 L rainfall can infiltrate into the loess until below the zero flux plane.
The hydro-chemical composition, Dissolved Inorganic Carbon (DIC), Dissolved Organic Carbon (DOC), Particulate Organic Carbon (POC) and δ13CDIC, δ13CPOC in spring water discharging from loess section in Qiushe village, Dudian town, Lingtai county, Gansu province of Northwestern China were determined, and CO2 consumption of carbonate weathering during rainfall recharge was estimated in this study. The results show that the chemical type of groundwater in study area is HCO3-Ca?Mg type. The Saturation Index of calcite (SIc) in spring water (above 0) displays the springs are saturated, however, the spring hardly appears the phenomenon of massive precipitation. The DIC concentration in groundwater of loess area is 5.25~5.45mmol/L, and the DOC concentration is 0.59 ~ 0.62 mg/L, lower than that in surface water. While POC concentration is high due to the mixture of loess particle matter. The δ13C of DIC in springs and wells ranged from -9.19‰ to -8.90‰. The positive distribution of δ13CDIC may be attributed to the repeated exchange of C isotope during the process of carbonate weathering and precipitation. The δ13CPOC ranged from -19.99‰ ~ -18.87‰, consistent with the isotope ratio of the organic carbon in loess. The HCO3-, Ca2+ and Mg2+ in groundwater mainly derive from the weathering of carbonate in loess. According to the ion balance of carbonate weathering reaction, the CO2 sink by carbonate weathering is calculated up to 2.82mmol/L. In other words, the 2.82mmol CO2 can be absorbed by carbonate weathering when 1 L rainfall can infiltrate into the loess until below the zero flux plane.
2017, 15(5):127-133.
Abstract:
Manas River Basin of Xinjiang is a region with great efforts to develop water resources and a higher level of economic development. Based on the trend analysis of the monitoring data of typical profile composed of 13 monitoring wells from 2010 to 2014 in Manas River Basin, the conclusion that groundwater level of the whole profile showed continual declination is draw. The decreasing rate of groundwater level of single unconfined groundwater area in upper alluvial plain was 0.65～0.83 m/a(with an average of 0.74 m/a); the decreasing rate of groundwater level of overflow zone in middle was 1.12 m/a; the decreasing rate of groundwater level in upper part and lower part of alluvial fine soil plain area were 0.59～3.07 m/a(with an average of 1.77 m/a) and 0.35～3.98 m/a respectively(with an average of 2.41 m/a). Annual decreasing rate of groundwater level from upstream and downstream showed an increasing trend. In terms of the annual variance of groundwater level, the change type of groundwater depth in alluvial plain was down-up-down; the type in overflow zone and north area was up-down-up. Groundwater dynamic type of single unconfined groundwater area in upper alluvial plain is infiltration-runoff type, groundwater dynamic type from overflow zone to alluvial fine soil plain area is exploitation type. Because the regional groundwater level continued to decline, present situation groundwater depth(5.89～67.46 m) is much higher than critical depth of desertification(6.0 m), ecological environment is facing deterioration. Based on the analysis of water resources utilization in Shihezi City and Manas County, the factors of groundwater level falling are groundwater overexploitation and the effective utilization of regional water resources which reduced the groundwater recharge. Finally, it is proposed that water resources must be scientifically planned to reduce the area of irrigation and groundwater exploitation, and to carry out the mechanism of ecological compensation to make the economic and social sustainable development in the basin.
Manas River Basin of Xinjiang is a region with great efforts to develop water resources and a higher level of economic development. Based on the trend analysis of the monitoring data of typical profile composed of 13 monitoring wells from 2010 to 2014 in Manas River Basin, the conclusion that groundwater level of the whole profile showed continual declination is draw. The decreasing rate of groundwater level of single unconfined groundwater area in upper alluvial plain was 0.65～0.83 m/a(with an average of 0.74 m/a); the decreasing rate of groundwater level of overflow zone in middle was 1.12 m/a; the decreasing rate of groundwater level in upper part and lower part of alluvial fine soil plain area were 0.59～3.07 m/a(with an average of 1.77 m/a) and 0.35～3.98 m/a respectively(with an average of 2.41 m/a). Annual decreasing rate of groundwater level from upstream and downstream showed an increasing trend. In terms of the annual variance of groundwater level, the change type of groundwater depth in alluvial plain was down-up-down; the type in overflow zone and north area was up-down-up. Groundwater dynamic type of single unconfined groundwater area in upper alluvial plain is infiltration-runoff type, groundwater dynamic type from overflow zone to alluvial fine soil plain area is exploitation type. Because the regional groundwater level continued to decline, present situation groundwater depth(5.89～67.46 m) is much higher than critical depth of desertification(6.0 m), ecological environment is facing deterioration. Based on the analysis of water resources utilization in Shihezi City and Manas County, the factors of groundwater level falling are groundwater overexploitation and the effective utilization of regional water resources which reduced the groundwater recharge. Finally, it is proposed that water resources must be scientifically planned to reduce the area of irrigation and groundwater exploitation, and to carry out the mechanism of ecological compensation to make the economic and social sustainable development in the basin.
2017, 15(5):134-140.
Abstract:
There are serious seepage and gushing of a sluice hub. The cavity and distribution scope between Sluice floor and foundation surrounding is carried out based on shear-wave impact imaging method (SIIM)，results is show that SIIM can reduce the interfere of water and steel mesh. The exploration results also provide the reliable basic data in terms of design repair and reinforcement the hydraulic project. At first，this paper describes the principle of the detection method，and gives the detection data processing，and develops cavity standards by numerical simulation. Finally, the defect distribution of sluice floor was completed. Detection conclusion as follow:1）Sluice floor presence void and some void is formed on the leakage passage which caused gushing water on the downstream side;2）void of sluice floor which greater than 20% need grouting treatment for timely, moderate void need further exploration, the other void which is less severe without treatment;3）Recommended for monitoring vertical deformation and horizontal deformation of sluice, strict control of the maximum operating level to prevent sluices from collapse and decline. SIIM provides a reference method for similar hydraulic projects in defects exploration.
There are serious seepage and gushing of a sluice hub. The cavity and distribution scope between Sluice floor and foundation surrounding is carried out based on shear-wave impact imaging method (SIIM)，results is show that SIIM can reduce the interfere of water and steel mesh. The exploration results also provide the reliable basic data in terms of design repair and reinforcement the hydraulic project. At first，this paper describes the principle of the detection method，and gives the detection data processing，and develops cavity standards by numerical simulation. Finally, the defect distribution of sluice floor was completed. Detection conclusion as follow:1）Sluice floor presence void and some void is formed on the leakage passage which caused gushing water on the downstream side;2）void of sluice floor which greater than 20% need grouting treatment for timely, moderate void need further exploration, the other void which is less severe without treatment;3）Recommended for monitoring vertical deformation and horizontal deformation of sluice, strict control of the maximum operating level to prevent sluices from collapse and decline. SIIM provides a reference method for similar hydraulic projects in defects exploration.
2017, 15(5):141-145.
Abstract:
In the process of operation, the concrete dam’s vibration information is hard to be measured accurately, based on transmissibility function, the vibration excitation was applied to the concrete dam, and transmissibility function is established through the dynamic response information. In addition, the information characteristics and the correlation of the variable can be characterized by the information entropy and mutual information, based on that, a new identification and localization of structural damage index is presented. This method extracts damage character without obtaining the outside vibration excitation information. Concrete gravity dam of the simulation and experimental results show that while the damage degree is greater than 3%, applying the vibration excitation can well realize the damage identification, and it is suitable for single damage and multiple damaged. The local damage can be well identified by reasonable arrangement of the measuring points according to the structural characteristics, and with great practical application value in concrete dam’s damage identification.
In the process of operation, the concrete dam’s vibration information is hard to be measured accurately, based on transmissibility function, the vibration excitation was applied to the concrete dam, and transmissibility function is established through the dynamic response information. In addition, the information characteristics and the correlation of the variable can be characterized by the information entropy and mutual information, based on that, a new identification and localization of structural damage index is presented. This method extracts damage character without obtaining the outside vibration excitation information. Concrete gravity dam of the simulation and experimental results show that while the damage degree is greater than 3%, applying the vibration excitation can well realize the damage identification, and it is suitable for single damage and multiple damaged. The local damage can be well identified by reasonable arrangement of the measuring points according to the structural characteristics, and with great practical application value in concrete dam’s damage identification.
2017, 15(5):146-155.
Abstract:
Because of the limitations of traditional anti-scour measures for piers, we adopted a new device, ring-wing plate, to protect round-ended piers against scour. The plate changes the flow structure around the pier by reducing the descending flow, and thus reduces the scour of the pier by the descending flow. To study the protective effect of the ring-wing plate on round-ended piers against local scour, we conducted physical model tests with 3 sizes of round-ended piers and 3 installation positions of the ring-wing plate, and analyzed such hydraulic elements as the characteristics of the scour pits around the piers, vertical flow velocity, vertical turbulence intensity, and turbulence shear stress. The results showed that the scour of the 3 types of piers was all reduced, and the medium-sized piers had the greatest reduction in scour among the 3 sizes, with a 30% reduction in the volume of the scour pits. After the ring-wing plate was installed around the medium-sized piers, the vertical flow velocity before the piers declined to 0.039m/s and the vertical turbulence intensity to 0.025m/s; the turbulence shear stress above the plate increased while the turbulence shear stress under the plate decreased. The results indicated that the ring-wing plate can reduce the local scour of piers and has a high practical value.
Because of the limitations of traditional anti-scour measures for piers, we adopted a new device, ring-wing plate, to protect round-ended piers against scour. The plate changes the flow structure around the pier by reducing the descending flow, and thus reduces the scour of the pier by the descending flow. To study the protective effect of the ring-wing plate on round-ended piers against local scour, we conducted physical model tests with 3 sizes of round-ended piers and 3 installation positions of the ring-wing plate, and analyzed such hydraulic elements as the characteristics of the scour pits around the piers, vertical flow velocity, vertical turbulence intensity, and turbulence shear stress. The results showed that the scour of the 3 types of piers was all reduced, and the medium-sized piers had the greatest reduction in scour among the 3 sizes, with a 30% reduction in the volume of the scour pits. After the ring-wing plate was installed around the medium-sized piers, the vertical flow velocity before the piers declined to 0.039m/s and the vertical turbulence intensity to 0.025m/s; the turbulence shear stress above the plate increased while the turbulence shear stress under the plate decreased. The results indicated that the ring-wing plate can reduce the local scour of piers and has a high practical value.
2017, 15(5):156-163.
Abstract:
Based on previous research results as well as the scour and deposition changes and suspension characteristics of sediment in the pipeline, we identified the non-depositing critical velocity of pipeline transport of sediment considering the real-time changes in sediment concentration and particle size distribution along the pipeline. We compared the measured values with the calculated values of different models, and chose Fei Xiangjun’s model to calculate the non-depositing critical velocity of pipeline transport. Finally, on both theoretical and practical bases, we proposed the pipe diameter and sediment concentration for high-efficiency pipeline transport of sediment in Xiaolangdi Reservoir, which can be a reference for future testing or production practices. We proposed the high-efficiency transport parameters for two different diameters of 0.325m and 0.63m. The two conditions both had the following parameters: a sediment concentration of 620 kg/m3, a median particle size of 0.0512- 0.0629mm, and 0.14mm D90. The transportation velocity can be adjusted between 1.75m/s-2.08m/s and 2.08m/s-2.2m/s. The corresponding largest sand discharge quantity per month was 89500 tons and 347200 tons.
Based on previous research results as well as the scour and deposition changes and suspension characteristics of sediment in the pipeline, we identified the non-depositing critical velocity of pipeline transport of sediment considering the real-time changes in sediment concentration and particle size distribution along the pipeline. We compared the measured values with the calculated values of different models, and chose Fei Xiangjun’s model to calculate the non-depositing critical velocity of pipeline transport. Finally, on both theoretical and practical bases, we proposed the pipe diameter and sediment concentration for high-efficiency pipeline transport of sediment in Xiaolangdi Reservoir, which can be a reference for future testing or production practices. We proposed the high-efficiency transport parameters for two different diameters of 0.325m and 0.63m. The two conditions both had the following parameters: a sediment concentration of 620 kg/m3, a median particle size of 0.0512- 0.0629mm, and 0.14mm D90. The transportation velocity can be adjusted between 1.75m/s-2.08m/s and 2.08m/s-2.2m/s. The corresponding largest sand discharge quantity per month was 89500 tons and 347200 tons.
2017, 15(5):164-169.
Abstract:
In order to study the shear strength of the frozen interface between channel bed soil and concrete lining and its variation with the main influencing factors, a series of direct shear tests of the frozen interface between channel bed soil and concrete lining are performed. In these tests, the main influencing factors, such as soil moisture content, freezing temperature, normal stress level and freezing time, have been taken into consideration and then analyzed in detail. The experimental results show that interface existence phenomenon of local shear stress release at the initial stage of the shear tests, the release amount influenced by normal stress and soil moisture content, freezing time, but not affected by the imposed freezing temperature. Within the parameters of this test， the peak shear strength increases with the increase of soil moisture content, normal stress, freezing time, and with the decrease of freezing temperature; Essentially, the shear strength of the interface is cementation force, cohesive force and friction force between channel bed soil and concrete lining. The peak shear strength was mainly affected by cementation force due to frost. Cohesive force and friction force was mainly affected by normal stress and freezing time.
In order to study the shear strength of the frozen interface between channel bed soil and concrete lining and its variation with the main influencing factors, a series of direct shear tests of the frozen interface between channel bed soil and concrete lining are performed. In these tests, the main influencing factors, such as soil moisture content, freezing temperature, normal stress level and freezing time, have been taken into consideration and then analyzed in detail. The experimental results show that interface existence phenomenon of local shear stress release at the initial stage of the shear tests, the release amount influenced by normal stress and soil moisture content, freezing time, but not affected by the imposed freezing temperature. Within the parameters of this test， the peak shear strength increases with the increase of soil moisture content, normal stress, freezing time, and with the decrease of freezing temperature; Essentially, the shear strength of the interface is cementation force, cohesive force and friction force between channel bed soil and concrete lining. The peak shear strength was mainly affected by cementation force due to frost. Cohesive force and friction force was mainly affected by normal stress and freezing time.
2017, 15(5):170-175.
Abstract:
This paper took the bottom-flow energy dissipator of a diversion spillway tunnel of a project as the object of study. In the original test scheme, when the gate was half open, the discharged flow was off the bottom of the discharge chute, which was not conducive to dissipating the energy of the discharged flow. In this study, we altered the slope of the floor in the pressing slope section, and reduced the two slope sections of the discharge chute into one slope section. In the original scheme, there were repelled hydraulic jumps in the stilling pool, resulting in poor energy dissipation. To tackle this problem, we adopted a calculation formula of the minimum falling-sill depth that was aimed at controlling the maximum underflow speed, and determined the elevation of the floor of the stilling pool. After two optimization experiments, we eliminated the phenomenon in which the flow out of the gate was off the bottom of the discharge chute. The discharged flow was in a steady regime. There were stable submerged jumps to dissipate the energy in the stilling pool. The water flow out of the stilling pool connected well with the downstream flow. The underflow speed and time-averaged dynamic water pressure in the stilling pool were significantly reduced. The dissipation effect was good.
This paper took the bottom-flow energy dissipator of a diversion spillway tunnel of a project as the object of study. In the original test scheme, when the gate was half open, the discharged flow was off the bottom of the discharge chute, which was not conducive to dissipating the energy of the discharged flow. In this study, we altered the slope of the floor in the pressing slope section, and reduced the two slope sections of the discharge chute into one slope section. In the original scheme, there were repelled hydraulic jumps in the stilling pool, resulting in poor energy dissipation. To tackle this problem, we adopted a calculation formula of the minimum falling-sill depth that was aimed at controlling the maximum underflow speed, and determined the elevation of the floor of the stilling pool. After two optimization experiments, we eliminated the phenomenon in which the flow out of the gate was off the bottom of the discharge chute. The discharged flow was in a steady regime. There were stable submerged jumps to dissipate the energy in the stilling pool. The water flow out of the stilling pool connected well with the downstream flow. The underflow speed and time-averaged dynamic water pressure in the stilling pool were significantly reduced. The dissipation effect was good.
2017, 15(5):176-182.
Abstract:
The Tsangpo-Brahmaputra River is an important international river. Obtain the information of spatial pattern and change characteristic of Gross Domestic Product (GDP), will help to formulate reasonable international river management policy. However, traditional GDP data take administrative region as a statistical unit, is not convenient to statistic and analysis in international river regions. Based on the land cover data, we estimated the spatial distribution data of GDP in Tsangpo-Brahmaputra River basin. In Tsangpo-Brahmaputra River basin, India and Bangladesh have large GDP. Though the GDP in the ‘South Tibetan region’ and Bhutan is small, but growing fast. Compared to other economical section, the secondary industry accounted a small proportion in GDP, and this result indicated that the industrial development level is not high over the whole basin. In addition, agriculture accounted a large section in GDP, which is the major source of economy, and other section is small.
The Tsangpo-Brahmaputra River is an important international river. Obtain the information of spatial pattern and change characteristic of Gross Domestic Product (GDP), will help to formulate reasonable international river management policy. However, traditional GDP data take administrative region as a statistical unit, is not convenient to statistic and analysis in international river regions. Based on the land cover data, we estimated the spatial distribution data of GDP in Tsangpo-Brahmaputra River basin. In Tsangpo-Brahmaputra River basin, India and Bangladesh have large GDP. Though the GDP in the ‘South Tibetan region’ and Bhutan is small, but growing fast. Compared to other economical section, the secondary industry accounted a small proportion in GDP, and this result indicated that the industrial development level is not high over the whole basin. In addition, agriculture accounted a large section in GDP, which is the major source of economy, and other section is small.
2017, 15(5):183-189.
Abstract:
The actual cost of a construction project is composed of not only production costs, but also transaction costs. An influence path model is constructed to illustrate the influence path of the transaction costs borne by the owner. The model is tested by the structural equation modeling (SEM) using the data collected from construction project owners. The finding indicate that uncertainty in the transaction environment and mechanism appears to be the core construct of the model due to its strong linkages with transaction costs and the owner`s behavior, the contractor`s behavior, and project management efficiency. The uncertainty of the contractor`s behavior is also found to affect project management efficiency positively. A certainty behavior on the part of the owner reduces the uncertainty in the transaction environment and mechanism, increases the efficiency of project management, and reduces the transaction costs of construction project.
The actual cost of a construction project is composed of not only production costs, but also transaction costs. An influence path model is constructed to illustrate the influence path of the transaction costs borne by the owner. The model is tested by the structural equation modeling (SEM) using the data collected from construction project owners. The finding indicate that uncertainty in the transaction environment and mechanism appears to be the core construct of the model due to its strong linkages with transaction costs and the owner`s behavior, the contractor`s behavior, and project management efficiency. The uncertainty of the contractor`s behavior is also found to affect project management efficiency positively. A certainty behavior on the part of the owner reduces the uncertainty in the transaction environment and mechanism, increases the efficiency of project management, and reduces the transaction costs of construction project.
2017, 15(5):190-194.
Abstract:
In solar greenhouse, the evapotranspiration ( ET ) of Strawberry was investigated by the large scale weighting lysimeter method under drip irrigation. A statistic ET model was established with meteorological parameter, and crop coefficients and crop-pan coefficients were presented for each stage, respectively. We divided strawberry growth period into four stages, that were floral bud growing period, over-wintering period, full fruiting period, later fruiting period based on the character of water consumption. The results,1.Facilities of strawberry growth period of the water consumption intensity of whole growth period showed a trend of "U" type change, including over-wintering stage minimum water consumption, the strawberry seasonal ET was 406 mm and the seasonal average ET rate was 1.55 mm/d;2.Correlation analysis showed that leaf area index of strawberry water consumption intensity affected;3.Dripper spacing about 20cm is propitious to irrigation for strawberry.
In solar greenhouse, the evapotranspiration ( ET ) of Strawberry was investigated by the large scale weighting lysimeter method under drip irrigation. A statistic ET model was established with meteorological parameter, and crop coefficients and crop-pan coefficients were presented for each stage, respectively. We divided strawberry growth period into four stages, that were floral bud growing period, over-wintering period, full fruiting period, later fruiting period based on the character of water consumption. The results,1.Facilities of strawberry growth period of the water consumption intensity of whole growth period showed a trend of "U" type change, including over-wintering stage minimum water consumption, the strawberry seasonal ET was 406 mm and the seasonal average ET rate was 1.55 mm/d;2.Correlation analysis showed that leaf area index of strawberry water consumption intensity affected;3.Dripper spacing about 20cm is propitious to irrigation for strawberry.
2017, 15(5):195-201.
Abstract:
Based on the three dimensional incompressible fluid Reynolds averaged navier-stokes equation and RNG k - epsilon turbulence model, the numerical simulation of three-dimensional turbulent flow of a rectangular, semicircular and bell-shaped inlet pump with "ω" suction chamber back wall shape was carried out.This paper also has analyzed the influence of wall shape on hydraulic characteristics of pump device after bell inlet passage. Under the same flow rate,streamline distribution of the “ω” shape suction chamber passage was the most average; the vortex of the “ω” shape suction chamber passage was the smallest;Hydraulic loss in the “ω” shape suction chamber passage was 1cm smaller than that of the rectangular shape suction chamber passage.Velocity uniformity of the export section reached 93%, higher than the rectangle and the semicircle suction chamber inlet port to 2%;Export section speed weighted average Angle is 83.5 °; Pump running high efficient area flow range became wider . This research had significance for improving the design of suction chamber of the Bell type inlet.
Based on the three dimensional incompressible fluid Reynolds averaged navier-stokes equation and RNG k - epsilon turbulence model, the numerical simulation of three-dimensional turbulent flow of a rectangular, semicircular and bell-shaped inlet pump with "ω" suction chamber back wall shape was carried out.This paper also has analyzed the influence of wall shape on hydraulic characteristics of pump device after bell inlet passage. Under the same flow rate,streamline distribution of the “ω” shape suction chamber passage was the most average; the vortex of the “ω” shape suction chamber passage was the smallest;Hydraulic loss in the “ω” shape suction chamber passage was 1cm smaller than that of the rectangular shape suction chamber passage.Velocity uniformity of the export section reached 93%, higher than the rectangle and the semicircle suction chamber inlet port to 2%;Export section speed weighted average Angle is 83.5 °; Pump running high efficient area flow range became wider . This research had significance for improving the design of suction chamber of the Bell type inlet.
2017, 15(5):202-208.
Abstract:
With a large number of pumped storage units put into operation, the stability problem of the unit caused by hydraulic vibration becomes serious. In this paper, we conducted field tests to obtain the unit vibration and run-out data of pumped storage units running at rated speed in both synchronous-condenser-as-pump (SCP) mode and pump operation (PO) mode. We used the frequency spectrum comparison analysis method to study the frequency spectrum of each measuring point in the two modes, and found differences in the frequency components of different measuring points. The results indicated that the vibration amplitude of the unit parts sustaining vertical load was larger in PO mode than in SCP mode. The 112.5Hz rotor-stator interaction frequency component mainly propagated vertically, and it was attenuated in the propagation. At some measuring points in PO mode, hydraulic interaction added runner blade passing frequency 56.25Hz and rotor-stator interaction frequency 112.5Hz to the frequency components. However, the addition of frequency components did not necessarily cause an increase in the mixed frequency amplitude of unit vibration and run-out. Since high frequencies such as 261Hz emerged in unit vibration, the dynamic analysis report of power houses and units should include higher frequencies in the future. This investigation provided detailed data for the runner research and design engineers.
With a large number of pumped storage units put into operation, the stability problem of the unit caused by hydraulic vibration becomes serious. In this paper, we conducted field tests to obtain the unit vibration and run-out data of pumped storage units running at rated speed in both synchronous-condenser-as-pump (SCP) mode and pump operation (PO) mode. We used the frequency spectrum comparison analysis method to study the frequency spectrum of each measuring point in the two modes, and found differences in the frequency components of different measuring points. The results indicated that the vibration amplitude of the unit parts sustaining vertical load was larger in PO mode than in SCP mode. The 112.5Hz rotor-stator interaction frequency component mainly propagated vertically, and it was attenuated in the propagation. At some measuring points in PO mode, hydraulic interaction added runner blade passing frequency 56.25Hz and rotor-stator interaction frequency 112.5Hz to the frequency components. However, the addition of frequency components did not necessarily cause an increase in the mixed frequency amplitude of unit vibration and run-out. Since high frequencies such as 261Hz emerged in unit vibration, the dynamic analysis report of power houses and units should include higher frequencies in the future. This investigation provided detailed data for the runner research and design engineers.
Mobile website
® 2024 All Rights Reserved
冀公网安备13010502002656号
冀公网安备13010502002656号 冀ICP备14004744号-5