Volume 16,Issue 2,2018 Table of Contents
2018, 16(2):1-6.
Abstract:
Water pollution incidents occur frequently in the natural river systems. How to operate the reservoirs on rivers to minimize the pollution loss is surely of great significance to the emergency disposal. In this paper, we established several corresponding models for the sequential processes of source identification, prediction of contaminant concentration, and reservoir operation. Using numerical simulation method, we optimized the reservoir operation scheme. Eventually , we proposed a relatively complete technical system for emergency disposal and then applied it to the case of Hejiang pollution incident in 2013. Results showed that the simulated time series of contaminant concentration were similar to the measured series. The optimized scheme and its disposal result generally fit the actual situation. The results indicated that the proposed technical system of emergency disposal with reservoir operation is feasible and efficient for real sudden water pollution incidents in natural rivers.
Water pollution incidents occur frequently in the natural river systems. How to operate the reservoirs on rivers to minimize the pollution loss is surely of great significance to the emergency disposal. In this paper, we established several corresponding models for the sequential processes of source identification, prediction of contaminant concentration, and reservoir operation. Using numerical simulation method, we optimized the reservoir operation scheme. Eventually , we proposed a relatively complete technical system for emergency disposal and then applied it to the case of Hejiang pollution incident in 2013. Results showed that the simulated time series of contaminant concentration were similar to the measured series. The optimized scheme and its disposal result generally fit the actual situation. The results indicated that the proposed technical system of emergency disposal with reservoir operation is feasible and efficient for real sudden water pollution incidents in natural rivers.
2018, 16(2):7-13.
Abstract:
"To explore the preparation of natural resources asset balance-sheet(NRABs) , and audit outgoing leading cadres concerning natural resources assets" is a major decision of the Third Plenary Session of the 18th CPC Central Committee, and is also very important to speeding up the construction of China's ecological civilization. In this article, two aspects about NRABs are discussed: the accounting object and the structural design of NRABs compilation. This article holds that the accounting object of NRABs should be the natural elements that exist extensively in nature, can be used by humans, and possess future economic benefits; it has both natural and economic properties. The NRABs includes three parts: the beginning inventory stock, ending inventory stock, and stock change during the accounting period. As an example, this article presents the land resource asset balance-sheet of Zhuxi county in Hubei province in 2013. It contains a substance accounting table and a value accounting table.The results show that at the end of 2013, Zhuxi county had 3.23×105hm2 of land resources valued at 8.994 billion yuan, which was a decrease of 42.86 hm2 in area and 8.6623 million yuan in value. The forest land declined, and the cultivated land increased. The land planning should protect forest land and water, tap the ecological service value of various land types, and maintain balance between the provisioning services, regulating services, supporting services, and cultural services in the region.
"To explore the preparation of natural resources asset balance-sheet(NRABs) , and audit outgoing leading cadres concerning natural resources assets" is a major decision of the Third Plenary Session of the 18th CPC Central Committee, and is also very important to speeding up the construction of China's ecological civilization. In this article, two aspects about NRABs are discussed: the accounting object and the structural design of NRABs compilation. This article holds that the accounting object of NRABs should be the natural elements that exist extensively in nature, can be used by humans, and possess future economic benefits; it has both natural and economic properties. The NRABs includes three parts: the beginning inventory stock, ending inventory stock, and stock change during the accounting period. As an example, this article presents the land resource asset balance-sheet of Zhuxi county in Hubei province in 2013. It contains a substance accounting table and a value accounting table.The results show that at the end of 2013, Zhuxi county had 3.23×105hm2 of land resources valued at 8.994 billion yuan, which was a decrease of 42.86 hm2 in area and 8.6623 million yuan in value. The forest land declined, and the cultivated land increased. The land planning should protect forest land and water, tap the ecological service value of various land types, and maintain balance between the provisioning services, regulating services, supporting services, and cultural services in the region.
2018, 16(2):14-20.
Abstract:
To solve the prblem of the dwindling fish resources in the lower reaches of the Fengman reservoir, we conducted the study on hydrological regime suitable for fishes on the basis of satisfying the minimum ecological water demand. We selected hydrological regime indicators that changed severely and were suitable for fishes, and used them to establish an ecological integrity function. Using the proposed function as the ecological objective, we established a multi-objective optimal scheduling model. Results showed that this model could improve ecological integrity by at least 48% . The memberships of flow rising rate and high flow pulse number increased by 0.112 and 0.261 respectively. The flow rising rate was well improved in dry years. The high flow pulse number was improved greatly in dry years and slig htly in wet years. This model can significantly improve the ecological integrity , and can provide a reference for the watershed with fish restoration tasks.
To solve the prblem of the dwindling fish resources in the lower reaches of the Fengman reservoir, we conducted the study on hydrological regime suitable for fishes on the basis of satisfying the minimum ecological water demand. We selected hydrological regime indicators that changed severely and were suitable for fishes, and used them to establish an ecological integrity function. Using the proposed function as the ecological objective, we established a multi-objective optimal scheduling model. Results showed that this model could improve ecological integrity by at least 48% . The memberships of flow rising rate and high flow pulse number increased by 0.112 and 0.261 respectively. The flow rising rate was well improved in dry years. The high flow pulse number was improved greatly in dry years and slig htly in wet years. This model can significantly improve the ecological integrity , and can provide a reference for the watershed with fish restoration tasks.
2018, 16(2):21-28.
Abstract:
Long-distance water transfer projects have large carrying capacity, numerous control gate groups and offtake groups, and put high requirements on controlling . In the event of a water pollution incident, it is essential to ensure the stability of the water transfer process and to handle the emergency efficiently. In this paper we studied the hydraulic control schemes of level ó water pollution in the main channel of the Middle Route of the South-to-North Water Transfer Project. We put forward the emergency handling strategy of level ó water pollution, and determined a division method of hydraulic control units based on the hydraulic characteristics of the offtakes. Taking Jing-shi section as an example, we proposed three emergency contro lschemes, and established a coupled model of one-dimensional hydraulics and water quality to simulate the flow of water and the transport of typical pollutants under different control schemes. The research showed that the three emergency control schemes could all achieve the emergency control objectives by using the channel's own storage capacity or exercising the control function of the offtakes without abandoning the water or significantly influencing the operation of the upper and lower reaches.
Long-distance water transfer projects have large carrying capacity, numerous control gate groups and offtake groups, and put high requirements on controlling . In the event of a water pollution incident, it is essential to ensure the stability of the water transfer process and to handle the emergency efficiently. In this paper we studied the hydraulic control schemes of level ó water pollution in the main channel of the Middle Route of the South-to-North Water Transfer Project. We put forward the emergency handling strategy of level ó water pollution, and determined a division method of hydraulic control units based on the hydraulic characteristics of the offtakes. Taking Jing-shi section as an example, we proposed three emergency contro lschemes, and established a coupled model of one-dimensional hydraulics and water quality to simulate the flow of water and the transport of typical pollutants under different control schemes. The research showed that the three emergency control schemes could all achieve the emergency control objectives by using the channel's own storage capacity or exercising the control function of the offtakes without abandoning the water or significantly influencing the operation of the upper and lower reaches.
2018, 16(2):29-37.
Abstract:
Analysis of the compositions, nature, and origins of the characteristic contaminants in wastewaters is important for water pollution control, treatment of pollution accidents, and the responsibility determination of environmental quality . Fluorescence spectroscopy can be used to analyze humic substances, amino acids, fluorescent whitening agents, lignin, polycyclic aromatic hydrocarbons and so on in wastewaters based on the characteristic fluorescence spectra of these substances. This paper first introduces the principle of fluorescence spectroscopy . Then it summarizes the applications of three-dimensional fluorescence spectroscopy and synchronous fluorescence spectroscopy in the study of characteristic dissolved or ganic matters in wastew aters. It also discusses the impacts of environmental factors on fluorescence spectroscopy. Finally, it provides an outlook of the future development of this technology with a view to providing a reliable analytical approach for characteristic dissolved organic matters in wastewaters.
Analysis of the compositions, nature, and origins of the characteristic contaminants in wastewaters is important for water pollution control, treatment of pollution accidents, and the responsibility determination of environmental quality . Fluorescence spectroscopy can be used to analyze humic substances, amino acids, fluorescent whitening agents, lignin, polycyclic aromatic hydrocarbons and so on in wastewaters based on the characteristic fluorescence spectra of these substances. This paper first introduces the principle of fluorescence spectroscopy . Then it summarizes the applications of three-dimensional fluorescence spectroscopy and synchronous fluorescence spectroscopy in the study of characteristic dissolved or ganic matters in wastew aters. It also discusses the impacts of environmental factors on fluorescence spectroscopy. Finally, it provides an outlook of the future development of this technology with a view to providing a reliable analytical approach for characteristic dissolved organic matters in wastewaters.
2018, 16(2):38-44.
Abstract:
In order to study the effects of low impact development ( LID) design on runoff pollution reduction and the effects of increasing rainwater infiltration by LID facilities on soil desalination in artificial island area, we designed LID configurations for different goals using the rainfall-runoff management model - SWMM. We investigated the runoff pollution reduction effect using the water quality model in SWMM. The salt suppression effect in the model was evaluated in terms of the relationship between infiltration amount and shallow water table. The results showed that the LID facilities have a significant impact on pollution reduction. Green roof performs well in reducing runoff pollution from the roofs. Ecological grass swale has a good effect on reducing the road runoff pollution. Permeable pavement is the best at increasing rainwater infiltration and reducing soil salinity. Rainwater tank with off-peak drainage function has a good infiltration effect. This paper provides a decision-making basis for planning the use of LID for water resources management on artificial islands.
In order to study the effects of low impact development ( LID) design on runoff pollution reduction and the effects of increasing rainwater infiltration by LID facilities on soil desalination in artificial island area, we designed LID configurations for different goals using the rainfall-runoff management model - SWMM. We investigated the runoff pollution reduction effect using the water quality model in SWMM. The salt suppression effect in the model was evaluated in terms of the relationship between infiltration amount and shallow water table. The results showed that the LID facilities have a significant impact on pollution reduction. Green roof performs well in reducing runoff pollution from the roofs. Ecological grass swale has a good effect on reducing the road runoff pollution. Permeable pavement is the best at increasing rainwater infiltration and reducing soil salinity. Rainwater tank with off-peak drainage function has a good infiltration effect. This paper provides a decision-making basis for planning the use of LID for water resources management on artificial islands.
2018, 16(2):45-50.
Abstract:
Chaohe River Basin is an important water source of Beijing . Due to the environmental change, a significant variation occurred to the rainfall-runoff relatio nship of Chaohe River Basin, and this change affected the regional water supply seriously . We analyzed the variation of rainfall-runoff relationship with the long-term hydro-meteorological data (from 1961 to 2014) of Chaohe River Basin, and established an empirical statistical analysis model to analyze quantitatively the impact of climate change and human activity on the runoff condition. The results showed that (1) the runoff changed drastically , and presented a marked dropping trend after 2000, whereas the precipitation showed an insignificant declining trend. (2) The relationship between rainfall and runoff changed abruptly in 1979 and 1998. (3) The runoff coefficient decreased significantly after 1979, and human activity kept a negative effect on runoff, and was always the more dominant factor as compared to climate change. (4) The contribution rate of human activity was -109.75% during 1979 to 1998 and -88.97% during 1999 to 2014, while the contribution rate of climate change was 9.75% during 1979 to 1998 and -11.03% during 1999 to 2014.
Chaohe River Basin is an important water source of Beijing . Due to the environmental change, a significant variation occurred to the rainfall-runoff relatio nship of Chaohe River Basin, and this change affected the regional water supply seriously . We analyzed the variation of rainfall-runoff relationship with the long-term hydro-meteorological data (from 1961 to 2014) of Chaohe River Basin, and established an empirical statistical analysis model to analyze quantitatively the impact of climate change and human activity on the runoff condition. The results showed that (1) the runoff changed drastically , and presented a marked dropping trend after 2000, whereas the precipitation showed an insignificant declining trend. (2) The relationship between rainfall and runoff changed abruptly in 1979 and 1998. (3) The runoff coefficient decreased significantly after 1979, and human activity kept a negative effect on runoff, and was always the more dominant factor as compared to climate change. (4) The contribution rate of human activity was -109.75% during 1979 to 1998 and -88.97% during 1999 to 2014, while the contribution rate of climate change was 9.75% during 1979 to 1998 and -11.03% during 1999 to 2014.
2018, 16(2):51-58.
Abstract:
The data assimilation method can improve the timeliness and accuracy of numerical fo recasting , and has been applied and developing rapidly in the field of hydrology . In order to improve the accuracy of runoff fo recast of Xinanjiang model, we adopted the ensemble Kalman filter method for synchronous correction of the model parameters and state variables. We designed anumerical experiment of the three-component Xinanjiang model under ideal conditions, and analyzed the effects of the mean and variance of parameters, the ensemble size, and the sensitivity and correlation of parameters on the data assimilation with consideration to the uncertainty of the model itself, model parameters, and the observation data. Results showed that the ensemble Kalman filter algorithm is feasible. Moreover, the accur cy of data assimilation can be improved when the mean value of the parameter is closer to the true value, the variance is increased appropriately , the ensemble size is proper, the sensitivity of parameters is lower, and the correlation between parameters and variables is small. This study can provide a reference for similar research of data assimilation.
The data assimilation method can improve the timeliness and accuracy of numerical fo recasting , and has been applied and developing rapidly in the field of hydrology . In order to improve the accuracy of runoff fo recast of Xinanjiang model, we adopted the ensemble Kalman filter method for synchronous correction of the model parameters and state variables. We designed anumerical experiment of the three-component Xinanjiang model under ideal conditions, and analyzed the effects of the mean and variance of parameters, the ensemble size, and the sensitivity and correlation of parameters on the data assimilation with consideration to the uncertainty of the model itself, model parameters, and the observation data. Results showed that the ensemble Kalman filter algorithm is feasible. Moreover, the accur cy of data assimilation can be improved when the mean value of the parameter is closer to the true value, the variance is increased appropriately , the ensemble size is proper, the sensitivity of parameters is lower, and the correlation between parameters and variables is small. This study can provide a reference for similar research of data assimilation.
2018, 16(2):59-63.
Abstract:
In order to study the effects of gravel properties on soil infiltration and runoff process in soil-rock medium, we conducted laboratory soil column experiments. We mixed two different rock fragments (gneiss and limestone) with the same soil. The gravel mass proportions (of the soil-rock medium) were 15% , 45% , 65% , and 90% respectively. Then, the relationship between cumulative infiltration and time were fitted with the Horton model and the Philip model. The results showed that: (1) For the same rock within the same amount of time, the cumulative infiltration of soil would decrease with the increase of gravel content, and the runoff would increase with the increase of gravel content. (2) With the same gravel proportion, within the same amount of time, the cumulative infiltration of gneiss was greater than that of limestone, and the runoff was less than that of limestone. (3) The Philip model and the Horton model can be used to fit the relationship between cumulative infiltration and time. As the gravel content increased, the infiltration rate A (if) tended to decrease, the soil infiltration rate Stended to decrease, and the initial infiltr ation rate ii tended to increase.
In order to study the effects of gravel properties on soil infiltration and runoff process in soil-rock medium, we conducted laboratory soil column experiments. We mixed two different rock fragments (gneiss and limestone) with the same soil. The gravel mass proportions (of the soil-rock medium) were 15% , 45% , 65% , and 90% respectively. Then, the relationship between cumulative infiltration and time were fitted with the Horton model and the Philip model. The results showed that: (1) For the same rock within the same amount of time, the cumulative infiltration of soil would decrease with the increase of gravel content, and the runoff would increase with the increase of gravel content. (2) With the same gravel proportion, within the same amount of time, the cumulative infiltration of gneiss was greater than that of limestone, and the runoff was less than that of limestone. (3) The Philip model and the Horton model can be used to fit the relationship between cumulative infiltration and time. As the gravel content increased, the infiltration rate A (if) tended to decrease, the soil infiltration rate Stended to decrease, and the initial infiltr ation rate ii tended to increase.
2018, 16(2):64-73.
Abstract:
With Taihang mountain region (TMR, water source district of the North China Plain) as the object of research, we established the WEP-L ( Water and Energy transfer Processes in Large river basins) model to simulate the water cycle process in the TMR, and analyzed the impacts of climatic fluctuation and land-cover change on the variation of blue water and green water from 1980 to 2000. The results showed that there was a clear distinction between the distribution of blue water and green water in the Hai River basin part (HRBP) and that in the Yellow River basin part (YRBP) . In HRBP, the blue water tended to increase and the green water tended to decrease; whereas in YRBP, they showed the oppositetr end. Climatic fluctuation was the leading cause of the blue water decrease in the Taihang mountain region. The land use/ cover change was the determining fact or of green water variation. The expansion of vegetation would increase green water resources but it would significantly reduce the blue water which is crucial for economic and social development. The resource development and space optimization of the mountain region should give main consideration to the reasonable regulation of blue water and green water.
With Taihang mountain region (TMR, water source district of the North China Plain) as the object of research, we established the WEP-L ( Water and Energy transfer Processes in Large river basins) model to simulate the water cycle process in the TMR, and analyzed the impacts of climatic fluctuation and land-cover change on the variation of blue water and green water from 1980 to 2000. The results showed that there was a clear distinction between the distribution of blue water and green water in the Hai River basin part (HRBP) and that in the Yellow River basin part (YRBP) . In HRBP, the blue water tended to increase and the green water tended to decrease; whereas in YRBP, they showed the oppositetr end. Climatic fluctuation was the leading cause of the blue water decrease in the Taihang mountain region. The land use/ cover change was the determining fact or of green water variation. The expansion of vegetation would increase green water resources but it would significantly reduce the blue water which is crucial for economic and social development. The resource development and space optimization of the mountain region should give main consideration to the reasonable regulation of blue water and green water.
2018, 16(2):74-80.
Abstract:
In order to reduce the influence of the uncertainty of hydrological models on hydrological simulation and improve the actual application effect of the models, we took the Yalong River basin as an example, and constructed four commonly used hydrological models: SWAT model, BTOPMC model, VIC model, and DTVG model. We conducted independent simulation using these models with the same input data and simulation time range. Then, we calculated the simulation results of the four models using the Multi-model Ensemble Out put System independently developed by Beijing Normal University based on the artificial neural net work method to obtain the flow hydrograph and error, and compared them with the results of the four models. The results indicated that the correlation coefficient and Nash efficiency coefficient of the multi-model ensemble simulation were both above 0.90, which was a great improvement in accuracy than the independent models. The results were stable and consistent with the actual runoff process. These indicated that the multi-model ensemble hydrological simulation had good applicability in this river basin.
In order to reduce the influence of the uncertainty of hydrological models on hydrological simulation and improve the actual application effect of the models, we took the Yalong River basin as an example, and constructed four commonly used hydrological models: SWAT model, BTOPMC model, VIC model, and DTVG model. We conducted independent simulation using these models with the same input data and simulation time range. Then, we calculated the simulation results of the four models using the Multi-model Ensemble Out put System independently developed by Beijing Normal University based on the artificial neural net work method to obtain the flow hydrograph and error, and compared them with the results of the four models. The results indicated that the correlation coefficient and Nash efficiency coefficient of the multi-model ensemble simulation were both above 0.90, which was a great improvement in accuracy than the independent models. The results were stable and consistent with the actual runoff process. These indicated that the multi-model ensemble hydrological simulation had good applicability in this river basin.
2018, 16(2):81-86.
Abstract:
At present, with the rapid development of remote sensing and image processing technologies, using remote sensing data for analyzing and monitoring water resources has become an inevitable trend. The five Central Asian countries are located at the core of Eurasia, and are considered as a stronghold of the "Silk Road" economicbelt . They have little rainfall all the year round, and differ greatly in water area. Based on Landsat-TM/ETM+ imagery , using the method of decision tree classification, we extracted the information of Central Asian water, and selected the major lakes and canals of Central Asia as the typical research areas to study the change of water area in 2000, 2010, and 2015. The results demonst rated that the total water area of Central Asia is 123 984. 80 km2 , which includes 111 856 km2 of lake area, 6 323.59 km2 of river area, and 5804.58 km2 of pond area. These three types respectively accounted for 90.21% , 5.10% , and 4.68% of the total water area. In addition, while Uzbekistan has abundant water resources, the other countries in Central Asia are all relatively short of water resources. Among the typical areas, the Aral Sea, Irtysh River, and Ural River have large coefficients of deterioration, which are 41.18% , 24.82% , and 14.68% respectively. Generally, the water area is decreasing year by year in Centr al Asia. The study on the distribution and dynamic change of water resources in Central Asia can contribute to "The Belt and Road" strategy .
At present, with the rapid development of remote sensing and image processing technologies, using remote sensing data for analyzing and monitoring water resources has become an inevitable trend. The five Central Asian countries are located at the core of Eurasia, and are considered as a stronghold of the "Silk Road" economicbelt . They have little rainfall all the year round, and differ greatly in water area. Based on Landsat-TM/ETM+ imagery , using the method of decision tree classification, we extracted the information of Central Asian water, and selected the major lakes and canals of Central Asia as the typical research areas to study the change of water area in 2000, 2010, and 2015. The results demonst rated that the total water area of Central Asia is 123 984. 80 km2 , which includes 111 856 km2 of lake area, 6 323.59 km2 of river area, and 5804.58 km2 of pond area. These three types respectively accounted for 90.21% , 5.10% , and 4.68% of the total water area. In addition, while Uzbekistan has abundant water resources, the other countries in Central Asia are all relatively short of water resources. Among the typical areas, the Aral Sea, Irtysh River, and Ural River have large coefficients of deterioration, which are 41.18% , 24.82% , and 14.68% respectively. Generally, the water area is decreasing year by year in Centr al Asia. The study on the distribution and dynamic change of water resources in Central Asia can contribute to "The Belt and Road" strategy .
2018, 16(2):87-92.
Abstract:
The environment in Hetian river basin is fragile. The runoff is extremely vulnerable to climate changes. Through the analysis of data from 1980 to 2013, we found that the annual precipitation at Tong Gu Zi Lu Ke station showed a significant increasing trend at a rate of 18 mm/(10a) . The annual average temperature was increasing by 0.232℃/(10a). The highest temperature appeared in 2007; the lowest temperature appeared in 2012. The annual sunshine hours were decreasing at a rate of 21.5 W/( m2·( 10a) ). The annual runoff was increasing at a rate of 23.5×107m3/(10a) . The runoff had a stronger correlation with antecedent temper ature than precipitation.
The environment in Hetian river basin is fragile. The runoff is extremely vulnerable to climate changes. Through the analysis of data from 1980 to 2013, we found that the annual precipitation at Tong Gu Zi Lu Ke station showed a significant increasing trend at a rate of 18 mm/(10a) . The annual average temperature was increasing by 0.232℃/(10a). The highest temperature appeared in 2007; the lowest temperature appeared in 2012. The annual sunshine hours were decreasing at a rate of 21.5 W/( m2·( 10a) ). The annual runoff was increasing at a rate of 23.5×107m3/(10a) . The runoff had a stronger correlation with antecedent temper ature than precipitation.
2018, 16(2):93-99.
Abstract:
Selecting the appropriate probability distribution function (PDF) for hydrological variables is of significant importance to calculating standardized drought indices. In this study , we used the Principle of Maximum Entropy (POME) method to model the PDFs of aggregated monthly streamflow on varying time scales for 30 sub-basins of the Hanjiang River Basin. The first three original moments of the cumulative monthly streamflow data were chosen as the constraint functions for maximizing the entropy by the Lagrange Multiplier. The Streamflow Drought Index (SDI) was computed based on monthly streamflow records derived from several theoretical probability distributions such as POME, Normal, Gamma, Weibull, and Pearson Typeó . Results showed that the POME-based PDFs could make the best use of the information from observed records while avoiding mistakenly introducing redundant information. They showed satisfying applicability . We found that the PDFs of cumulative monthly streamflow would trend towards normalization as the time scale increased. The proposed method can be a practical tool for calculating hydrological drought indices, analyzing drought characteristics, and performing drought frequency analysis.
Selecting the appropriate probability distribution function (PDF) for hydrological variables is of significant importance to calculating standardized drought indices. In this study , we used the Principle of Maximum Entropy (POME) method to model the PDFs of aggregated monthly streamflow on varying time scales for 30 sub-basins of the Hanjiang River Basin. The first three original moments of the cumulative monthly streamflow data were chosen as the constraint functions for maximizing the entropy by the Lagrange Multiplier. The Streamflow Drought Index (SDI) was computed based on monthly streamflow records derived from several theoretical probability distributions such as POME, Normal, Gamma, Weibull, and Pearson Typeó . Results showed that the POME-based PDFs could make the best use of the information from observed records while avoiding mistakenly introducing redundant information. They showed satisfying applicability . We found that the PDFs of cumulative monthly streamflow would trend towards normalization as the time scale increased. The proposed method can be a practical tool for calculating hydrological drought indices, analyzing drought characteristics, and performing drought frequency analysis.
2018, 16(2):100-107.
Abstract:
The shortage of water resources in Jiaodong area is becoming increasingly serious with the expansion of urban population and the rapid development of industrial and agricultural production and economy in recent years. The four cities with serious water shortage in Jiaodong area ( Weifang, Qingdao, Yantai, and Weihai) were taken as the study areas. Inter-basin water transfer was implemented based on the East Route of South-to-North Water Transfer Project and the project of water diversion from Yellow River to Qingdao so as to alleviate the contradiction between supply and demand. The years of 2020 and 2025 were taken as the planning years. According to the water balance analysis, we built a multi-water source, multi-objective optimal allocation model that aimed for minimum water shortage and maximum benefits of the water transfer projects, and we determined the optimal allocation scheme for different water sources ( Yellow River, Yellow River and Yangtze River) . Results showed that when water was transferred from Yellow River a lone, the water shortage in the water-receiving area would decrease by 14%-83% and 10%-31% respectively in different planning years; when water was transferred from both Yellow River and Yangtze River, the water shortage in the water-receiving area would decrease by 28%-81% and 19%-53% respectively in different planning years. The optimal allocation scheme can effectively alleviate the contradiction between water supply and demand and alleviate the shortage of water resources in Jiaodong area, and thus lay the foundation for sustainable development in Jiaodong area.
The shortage of water resources in Jiaodong area is becoming increasingly serious with the expansion of urban population and the rapid development of industrial and agricultural production and economy in recent years. The four cities with serious water shortage in Jiaodong area ( Weifang, Qingdao, Yantai, and Weihai) were taken as the study areas. Inter-basin water transfer was implemented based on the East Route of South-to-North Water Transfer Project and the project of water diversion from Yellow River to Qingdao so as to alleviate the contradiction between supply and demand. The years of 2020 and 2025 were taken as the planning years. According to the water balance analysis, we built a multi-water source, multi-objective optimal allocation model that aimed for minimum water shortage and maximum benefits of the water transfer projects, and we determined the optimal allocation scheme for different water sources ( Yellow River, Yellow River and Yangtze River) . Results showed that when water was transferred from Yellow River a lone, the water shortage in the water-receiving area would decrease by 14%-83% and 10%-31% respectively in different planning years; when water was transferred from both Yellow River and Yangtze River, the water shortage in the water-receiving area would decrease by 28%-81% and 19%-53% respectively in different planning years. The optimal allocation scheme can effectively alleviate the contradiction between water supply and demand and alleviate the shortage of water resources in Jiaodong area, and thus lay the foundation for sustainable development in Jiaodong area.
2018, 16(2):108-114.
Abstract:
In order to better guide the development and utilization of ice and snow resources in western Tianshan mountains, it is of great importance to study the law of snowline change. With the help of the MODIS datafrom 2000 to 2016, the weather datafrom 1959 to 2015, and the DEM data, west udied the temporal and spatial variation of the snowline in Kashi river basin by using the remote sensing snowline method, the climate snowline method, and the fields of snowline altitude method. The results are as follows: (1) According to the remote sensing snowline method, the multi-year average (8 days) and the annual average snowline showed a rising tendency in the resear charea; on the seasonal scale, the snowline showed a rising tendency in spring and winter, and showed a declining tendency in autumn and summer. Based on the climatic data, the annual average snowline had a good response to precipitation, and the spring snowline had a good response to temperature. (2) According to the climate snowline method, the climate snowline was higher than the remote sensing snowline. From the climate perspective, the climate change caused the snowline to increase year by year. (3) It is shown from the analysis of the fields of snowline altitude that the distribution of the snowline is mainly influenced by to pography. With the 2000m height as the dividing line, the two parts of the fields of snowline altitude have different responses to precipitation.
In order to better guide the development and utilization of ice and snow resources in western Tianshan mountains, it is of great importance to study the law of snowline change. With the help of the MODIS datafrom 2000 to 2016, the weather datafrom 1959 to 2015, and the DEM data, west udied the temporal and spatial variation of the snowline in Kashi river basin by using the remote sensing snowline method, the climate snowline method, and the fields of snowline altitude method. The results are as follows: (1) According to the remote sensing snowline method, the multi-year average (8 days) and the annual average snowline showed a rising tendency in the resear charea; on the seasonal scale, the snowline showed a rising tendency in spring and winter, and showed a declining tendency in autumn and summer. Based on the climatic data, the annual average snowline had a good response to precipitation, and the spring snowline had a good response to temperature. (2) According to the climate snowline method, the climate snowline was higher than the remote sensing snowline. From the climate perspective, the climate change caused the snowline to increase year by year. (3) It is shown from the analysis of the fields of snowline altitude that the distribution of the snowline is mainly influenced by to pography. With the 2000m height as the dividing line, the two parts of the fields of snowline altitude have different responses to precipitation.
2018, 16(2):115-121.
Abstract:
Taking the sponge city demonstration project in Yixing city as the research object, we used SWMM software to generalize and model the study area and validated the fidelities of the model with actual monitoring data. The model was used to simulate the hydrology and water quality changes in the area at the rainfall intensity of the return period of 3, 5, 10, 15, 50, 100 years, and to analyze the regulation effect of permeable pavement on the ecosystem of city rainwater. The results showed the permeable pavement could reduce rainfall runoff by up to 19.74% and the runoff coefficient decreased by 21.93% . The overall runoff reduction effect increased along with the rainfall intensity, but the increase was small. As to conventional pollutants of SS, COD, TN, and TP, the reduction was up to 24.12% , 23.79% , 22.81% , and 21.90% , respectively. The permeable pavement could also delay the peak time of runoff volume and pollutant load concentration. This study presents a scientific evaluation on the effect of permeable pavement and provides reference for engineering design.
Taking the sponge city demonstration project in Yixing city as the research object, we used SWMM software to generalize and model the study area and validated the fidelities of the model with actual monitoring data. The model was used to simulate the hydrology and water quality changes in the area at the rainfall intensity of the return period of 3, 5, 10, 15, 50, 100 years, and to analyze the regulation effect of permeable pavement on the ecosystem of city rainwater. The results showed the permeable pavement could reduce rainfall runoff by up to 19.74% and the runoff coefficient decreased by 21.93% . The overall runoff reduction effect increased along with the rainfall intensity, but the increase was small. As to conventional pollutants of SS, COD, TN, and TP, the reduction was up to 24.12% , 23.79% , 22.81% , and 21.90% , respectively. The permeable pavement could also delay the peak time of runoff volume and pollutant load concentration. This study presents a scientific evaluation on the effect of permeable pavement and provides reference for engineering design.
18 Temporal and spatial variation characteristics of surface temperature in Guizhou during 1961-2013
2018, 16(2):122-131.
Abstract:
Using the daily 0 cm soil surface temperature data of Guizhou during 1961 to 2013, adopting the methods of ArcGIS spatial analysis, linear trend, wavelet analysis, and Mann Kendall nonparametric test, we analyzed the spatial distribution, change trend, mutation characteristics, and variation period of the surface temperature in Guizhou. The results showed that the annual and seasonal spatial distribution of average surface temperature and average minimum surface temperature was roughly increasing from northwestern Guizhou to southeastern Guizhou along with the increase of longitude and the decrease of altitude and latitude. The annual, autumn, and winter spatial distribution of average maximum surface temperature was roughly increasing from the northeast to the southwest of Guizhou along with the decrease of latitude and longitude and the increase of altitude. The annual and seasonal changes of aver agesurface temperature and average minimum surface temperature all showed a warming trend, which was especially prominent for the annual and seasonal changes of average minimum surface temperature. The annual, spring , summer, and autumn changes of average maximum surface temperature all showed a warming trend, but the winter change showed a slight downward trend. The annual and seasonal mutations of average surface temperature, average maximum surface temperature, and average minimum surface temperature concentrated in the 1990s, and the mutations were very significant in spring and autumn. The annual and seasonal variation periods of average surface temperature, average maximum surface temperature, and average minimum surface temperature were primarily long periods. The annual average surface temperature and annual average minimum surface temperature were both negatively correlated with the altitude and positively correlated with the longitude, while the annual average maximum surface temperature was negatively correlated with latitude.
Using the daily 0 cm soil surface temperature data of Guizhou during 1961 to 2013, adopting the methods of ArcGIS spatial analysis, linear trend, wavelet analysis, and Mann Kendall nonparametric test, we analyzed the spatial distribution, change trend, mutation characteristics, and variation period of the surface temperature in Guizhou. The results showed that the annual and seasonal spatial distribution of average surface temperature and average minimum surface temperature was roughly increasing from northwestern Guizhou to southeastern Guizhou along with the increase of longitude and the decrease of altitude and latitude. The annual, autumn, and winter spatial distribution of average maximum surface temperature was roughly increasing from the northeast to the southwest of Guizhou along with the decrease of latitude and longitude and the increase of altitude. The annual and seasonal changes of aver agesurface temperature and average minimum surface temperature all showed a warming trend, which was especially prominent for the annual and seasonal changes of average minimum surface temperature. The annual, spring , summer, and autumn changes of average maximum surface temperature all showed a warming trend, but the winter change showed a slight downward trend. The annual and seasonal mutations of average surface temperature, average maximum surface temperature, and average minimum surface temperature concentrated in the 1990s, and the mutations were very significant in spring and autumn. The annual and seasonal variation periods of average surface temperature, average maximum surface temperature, and average minimum surface temperature were primarily long periods. The annual average surface temperature and annual average minimum surface temperature were both negatively correlated with the altitude and positively correlated with the longitude, while the annual average maximum surface temperature was negatively correlated with latitude.
2018, 16(2):132-139.
Abstract:
Lateral inlet/outlet is the widely used form of flow transition structure in pumped storage power stations, and is always considered as the throat connecting the reservoir and water pipes. The two-direction flow structure of the lateral inlet/outlet is complicated and affects the operation efficiency and safety of engineering. The reasonable structure type of lateral inlet/outlet is the key to ensuring reasonable flow transition and engineering safety. The methods for studying the shape and hydraulic characteristics of lateral inlet/outlet mainly include physical model test, numerical simulation, and prototype observation. This paper summarizes the research results on the vortex flow, flow transition, and head loss at the lateral inlet/outlet. It analyzes the forming mechanism of vortex, the factors that induce vortex , and the engineering and non-engineering measures to inhibit vortex formation. It defines the engineering requirements of equilibrium transition flow and the structure design criteria that satisfy the equilibrium transition of flow. It also lists the structure parameters, transition flow characteristic numbers, and the water head loss coefficients at the lateral inlet/outlet of some projects.
Lateral inlet/outlet is the widely used form of flow transition structure in pumped storage power stations, and is always considered as the throat connecting the reservoir and water pipes. The two-direction flow structure of the lateral inlet/outlet is complicated and affects the operation efficiency and safety of engineering. The reasonable structure type of lateral inlet/outlet is the key to ensuring reasonable flow transition and engineering safety. The methods for studying the shape and hydraulic characteristics of lateral inlet/outlet mainly include physical model test, numerical simulation, and prototype observation. This paper summarizes the research results on the vortex flow, flow transition, and head loss at the lateral inlet/outlet. It analyzes the forming mechanism of vortex, the factors that induce vortex , and the engineering and non-engineering measures to inhibit vortex formation. It defines the engineering requirements of equilibrium transition flow and the structure design criteria that satisfy the equilibrium transition of flow. It also lists the structure parameters, transition flow characteristic numbers, and the water head loss coefficients at the lateral inlet/outlet of some projects.
2018, 16(2):140-145.
Abstract:
Many hydraulic structures are built on bedrocks, and most natural rock masses have joint fissures, which are prone to triggering hydraulic fracturing phenomenon under high water pressure. In order to study the hydraulic fracturing characteristics of fractured rock mass, we prepared specimens with pre-cast cracks using cement mortar as a substitute material of rock mass. We developed a water pressure loading system and a water sealing device, and used them to test the hydraulic fracturing of cement mortar specimens with differentinitial pre-cast crack lengths and widths. We determined the critical water pressure of pre-cast crack initiation and that of hydraulic fracturing of the specimens. The relationship between the critical water pressure of pre-cast crack initiation and that of hydraulic fracturing was analyzed, and the predictive formulas for the critical water pressures of pre-cast crack initiation and hydraulic fracturing were proposed. The test results showed that the critical water pressure of hydraulic fracturing of the specimens was 0.441 MPa-1.542 MPa. The critical water pressure of hydraulic fracturing would decrease as the initial pre-cast crack length and width increased when the other factors remained unchanged. The ratio between the critical water pressure of pre-cast crack initiation and the critical water pressure of hydraulic fracturing was 61.57%-64.17% , and it was independent of the initial crack length and width. Based on the stress intensity factor formula and the experimental results, we obtained the calculation formulas for the critical water pressure of pre-cast crack initiation and hydraulic fracturing of the specimens with consideration to the influence of the width of the pre-cast cracks.
Many hydraulic structures are built on bedrocks, and most natural rock masses have joint fissures, which are prone to triggering hydraulic fracturing phenomenon under high water pressure. In order to study the hydraulic fracturing characteristics of fractured rock mass, we prepared specimens with pre-cast cracks using cement mortar as a substitute material of rock mass. We developed a water pressure loading system and a water sealing device, and used them to test the hydraulic fracturing of cement mortar specimens with differentinitial pre-cast crack lengths and widths. We determined the critical water pressure of pre-cast crack initiation and that of hydraulic fracturing of the specimens. The relationship between the critical water pressure of pre-cast crack initiation and that of hydraulic fracturing was analyzed, and the predictive formulas for the critical water pressures of pre-cast crack initiation and hydraulic fracturing were proposed. The test results showed that the critical water pressure of hydraulic fracturing of the specimens was 0.441 MPa-1.542 MPa. The critical water pressure of hydraulic fracturing would decrease as the initial pre-cast crack length and width increased when the other factors remained unchanged. The ratio between the critical water pressure of pre-cast crack initiation and the critical water pressure of hydraulic fracturing was 61.57%-64.17% , and it was independent of the initial crack length and width. Based on the stress intensity factor formula and the experimental results, we obtained the calculation formulas for the critical water pressure of pre-cast crack initiation and hydraulic fracturing of the specimens with consideration to the influence of the width of the pre-cast cracks.
21 Numerical simulation on rectification measure of inverted T-shaped sill at forebay of pump station
2018, 16(2):146-150.
Abstract:
In order to rectify the bad flow pattern at the forebay of the pump station, in this paper we conducted numerical simulation of the forebay with inverted T-shaped sill based on the Fluent software using the N-S equation and Reliable k-ε turbulence model, and analyzed the influence of the geometrical parameters of the sill on the flow pattern and lateral flow velocity at the forebay. The results showed that without the rectification measure, the flow pattern at the forebay was turbulent. Adding an inverted T-shaped sill could significantly increase the flow rate of the side unit and improve the uniformity of the velocity distribution at the forebay . The location parameter and superstructure size of the inverted T-shaped sill had significant influence on the flow pattern at the forebay . The recommended location of the inverted T-shaped sill is 7.5D to the entrance of the intake pool. The recommended superstructure is 0.4H high and 0.1B wide.
In order to rectify the bad flow pattern at the forebay of the pump station, in this paper we conducted numerical simulation of the forebay with inverted T-shaped sill based on the Fluent software using the N-S equation and Reliable k-ε turbulence model, and analyzed the influence of the geometrical parameters of the sill on the flow pattern and lateral flow velocity at the forebay. The results showed that without the rectification measure, the flow pattern at the forebay was turbulent. Adding an inverted T-shaped sill could significantly increase the flow rate of the side unit and improve the uniformity of the velocity distribution at the forebay . The location parameter and superstructure size of the inverted T-shaped sill had significant influence on the flow pattern at the forebay . The recommended location of the inverted T-shaped sill is 7.5D to the entrance of the intake pool. The recommended superstructure is 0.4H high and 0.1B wide.
2018, 16(2):151-157.
Abstract:
In order to predict and analyze the influence of the construction of Riverside West Park on the flood discharging capacity of the outlet section of Nandu River, we established a two-dimensional flow numerical model based on the hydrody namic model of MIKE21 FM. Firstly , we used the measured flood data of the hydrological stations to calibrate and verify the roughness coefficient of the main channel and tidal flats. We adopted local roughness correction method and local topographic correction method as the generalization methods of the park model. Then, we simulated the water level and flow field changes at the outlet section under three typical conditions of flood and tide combinations. The calculation results of the two generalization methods were basically consistent. The topography and roughness of the river channel would change after the park is built, leading to the increase of the water level and main flow velocity. The water level increase value calculated by the local roughness correction method was slightly larger, but the water level was still lower than the design water level of the flood embankment. The construction of the park would not reduce the discharging capacity of the outlet section of Nandu River. A high-velocity area would appear near Simapo Island. It is necessary to take corresponding measures to prevent scouring .
In order to predict and analyze the influence of the construction of Riverside West Park on the flood discharging capacity of the outlet section of Nandu River, we established a two-dimensional flow numerical model based on the hydrody namic model of MIKE21 FM. Firstly , we used the measured flood data of the hydrological stations to calibrate and verify the roughness coefficient of the main channel and tidal flats. We adopted local roughness correction method and local topographic correction method as the generalization methods of the park model. Then, we simulated the water level and flow field changes at the outlet section under three typical conditions of flood and tide combinations. The calculation results of the two generalization methods were basically consistent. The topography and roughness of the river channel would change after the park is built, leading to the increase of the water level and main flow velocity. The water level increase value calculated by the local roughness correction method was slightly larger, but the water level was still lower than the design water level of the flood embankment. The construction of the park would not reduce the discharging capacity of the outlet section of Nandu River. A high-velocity area would appear near Simapo Island. It is necessary to take corresponding measures to prevent scouring .
2018, 16(2):158-163.
Abstract:
We tested in practical engineering the mechanical model of slope concrete slabs of winter water conveyance canals during the frost heaving of the bedsoil. Then we theoretically analyzed the influence of slope angle, water depth, and lining thickness on the inner forces of the rigid lining of the canal under the condition of a specific type of frost heaving force and calculation method. Results showed that the slope slab of the canal had a tendency to move upward along the slope during frost heaving of the bedsoil in winter. On the premise of overall stability of the slope, the innerforces and probability of canal damage due to frost heaving could both be greatly reduced by increasing slope angle, reducing canal bottom width, and rising water level. It is inadvisable to increase the slope slab thickness as a way to increase the frost heaving resistance capacity of the canal. The research findings can provide a new method for the anti-frost heaving design of water conveyance canals without ice cover in winter in seasonally frozen region. To design and adjust the hydraulic parameters of the canalso as to increase the water depth within the canal can reduce the probability of frost heaving damage to the canal, and can reduce the canal land area and earthwork volume.
We tested in practical engineering the mechanical model of slope concrete slabs of winter water conveyance canals during the frost heaving of the bedsoil. Then we theoretically analyzed the influence of slope angle, water depth, and lining thickness on the inner forces of the rigid lining of the canal under the condition of a specific type of frost heaving force and calculation method. Results showed that the slope slab of the canal had a tendency to move upward along the slope during frost heaving of the bedsoil in winter. On the premise of overall stability of the slope, the innerforces and probability of canal damage due to frost heaving could both be greatly reduced by increasing slope angle, reducing canal bottom width, and rising water level. It is inadvisable to increase the slope slab thickness as a way to increase the frost heaving resistance capacity of the canal. The research findings can provide a new method for the anti-frost heaving design of water conveyance canals without ice cover in winter in seasonally frozen region. To design and adjust the hydraulic parameters of the canalso as to increase the water depth within the canal can reduce the probability of frost heaving damage to the canal, and can reduce the canal land area and earthwork volume.
2018, 16(2):164-170.
Abstract:
Groundwater is an important water source of Jinghuiqu Irrigation District. The analysis of its dynamic characteristics provides important guidance to the development and utilization of water resources. Based on the groundwater depth data of Jinghuiqu Irrigation District during 1981-2010, we analyzed its interannual variation using linear tendency estimation method, cumulative departure, Sen slope estimation method, and Mann-Kendall trend test. We analyzed the mutation of groundwater depth using smoothing T test and two- dimensional regression mutation analysis. We determined the most important influence factors of groundwater depth using principal component analysis and grey relationship analysis. The results showed that the groundwater depth tended to increase during 1981-2010. The mutation happened in 1994. Before 1994, evaporation was the most important influence factor of groundwater depth. After 1994, the most important influence factors became evaporation, groundwater extraction, and canal water diversion.
Groundwater is an important water source of Jinghuiqu Irrigation District. The analysis of its dynamic characteristics provides important guidance to the development and utilization of water resources. Based on the groundwater depth data of Jinghuiqu Irrigation District during 1981-2010, we analyzed its interannual variation using linear tendency estimation method, cumulative departure, Sen slope estimation method, and Mann-Kendall trend test. We analyzed the mutation of groundwater depth using smoothing T test and two- dimensional regression mutation analysis. We determined the most important influence factors of groundwater depth using principal component analysis and grey relationship analysis. The results showed that the groundwater depth tended to increase during 1981-2010. The mutation happened in 1994. Before 1994, evaporation was the most important influence factor of groundwater depth. After 1994, the most important influence factors became evaporation, groundwater extraction, and canal water diversion.
25 Study on permeability variation and groundwater response under disturbance of deep coal seam mining
2018, 16(2):171-176.
Abstract:
There is a lack of research on groundwater disturbance caused by deep coal resource exploitation in western China. Based on the elastic-plastic theory , this paper studies the variation mechanism of the seepage capacity of the overlying strata and the response of the groundwater by using the fluid solid coupling numerical simulation software COMSOL. The simulation results showed that the change pattern of overburden permeability is different in different mining stress states. The overburden permeability increased in the tensile stress zone: at the top of the excavation space it increased by 26% , and in the surface subsidence basin it increased by 3% . The overburden permeability decreased in the stress compression zone: on both sides of the coal pillar it decreased by 43% , and at about 300m above the mining space it decreased by 18% . A groundwater drawdown funnel was formed with the water-flowing fractured zone as the center. As a result, the vertical hydraulic gradient and flow velocity of groundwater both increased significantly, while the water pressure was basically in the original state at about 300m above the mining space. The research results can provide theoretical support for reasonable exploitation of coal resources and scientific management of water resources in the arid area of China.
There is a lack of research on groundwater disturbance caused by deep coal resource exploitation in western China. Based on the elastic-plastic theory , this paper studies the variation mechanism of the seepage capacity of the overlying strata and the response of the groundwater by using the fluid solid coupling numerical simulation software COMSOL. The simulation results showed that the change pattern of overburden permeability is different in different mining stress states. The overburden permeability increased in the tensile stress zone: at the top of the excavation space it increased by 26% , and in the surface subsidence basin it increased by 3% . The overburden permeability decreased in the stress compression zone: on both sides of the coal pillar it decreased by 43% , and at about 300m above the mining space it decreased by 18% . A groundwater drawdown funnel was formed with the water-flowing fractured zone as the center. As a result, the vertical hydraulic gradient and flow velocity of groundwater both increased significantly, while the water pressure was basically in the original state at about 300m above the mining space. The research results can provide theoretical support for reasonable exploitation of coal resources and scientific management of water resources in the arid area of China.
2018, 16(2):177-181.
Abstract:
Compared with the qualitative study of seawater intrusion, the quantitative study can give a more direct description of the submarine groundwater discharge and inflow in the seawater intrusion area. We set up a 3-km-long monitoring section in an intertidal zone located in the north of Changyi City of Weifang. According to the data of groundwater level, water temperature, and conductivity, we conducted a quantitative estimation of the submarine groundwater exchange capacity by mathematical methods. The results of the calculation were used to evaluate the trend of seawater intrusion in the study area, and to provide a scientific basis for future groundwater monitoring in the area. The results showed that the inflow in the intertidal zone was obviously larger than the outflow , so the seawater is showing a trend of landward intrusion.
Compared with the qualitative study of seawater intrusion, the quantitative study can give a more direct description of the submarine groundwater discharge and inflow in the seawater intrusion area. We set up a 3-km-long monitoring section in an intertidal zone located in the north of Changyi City of Weifang. According to the data of groundwater level, water temperature, and conductivity, we conducted a quantitative estimation of the submarine groundwater exchange capacity by mathematical methods. The results of the calculation were used to evaluate the trend of seawater intrusion in the study area, and to provide a scientific basis for future groundwater monitoring in the area. The results showed that the inflow in the intertidal zone was obviously larger than the outflow , so the seawater is showing a trend of landward intrusion.
27 A preliminary assessment of wind energy resources in the Nansi Lake based on numerical simulation
2018, 16(2):182-188.
Abstract:
The assessment methods of regional wind resources based on meteorological stations and anemometer towers have some limitations. The former does not have access to the wind speed data of the fan wheel, and has low evaluation precision. The latter has difficulty in getting long-time observation data, cannot provide sufficient description of the interannual variability of the average wind speed, and has high evaluation cost. In this article, we selected the surrounding area of Nansi Lake as the object of study , constructed the numerical weather forecast mode of this region based on WRF, and realized the simulation of hourly wind field around Nansi Lake from 2000 to 2016. Extracting the simulation information of wind field at 80m height, we conducted preliminary evaluation of the wind energy resources in this region by studying the annual average wind speed, annual average wind power density, annual available hours, annual wind speed distribution, and prevailing wind direction. We held that the wind energy resources in this region have certain develo pment and utilization value. As it is close to the energy consumption centers such as the pumping stations group of the East Route of the South-to-North Water Transfer Project , the wind electricity can be used locally . This paper provides certain reference for checking and utilizing wind energy resources in this region.
The assessment methods of regional wind resources based on meteorological stations and anemometer towers have some limitations. The former does not have access to the wind speed data of the fan wheel, and has low evaluation precision. The latter has difficulty in getting long-time observation data, cannot provide sufficient description of the interannual variability of the average wind speed, and has high evaluation cost. In this article, we selected the surrounding area of Nansi Lake as the object of study , constructed the numerical weather forecast mode of this region based on WRF, and realized the simulation of hourly wind field around Nansi Lake from 2000 to 2016. Extracting the simulation information of wind field at 80m height, we conducted preliminary evaluation of the wind energy resources in this region by studying the annual average wind speed, annual average wind power density, annual available hours, annual wind speed distribution, and prevailing wind direction. We held that the wind energy resources in this region have certain develo pment and utilization value. As it is close to the energy consumption centers such as the pumping stations group of the East Route of the South-to-North Water Transfer Project , the wind electricity can be used locally . This paper provides certain reference for checking and utilizing wind energy resources in this region.
2018, 16(2):189-195.
Abstract:
Based on the k-epsilon turbulent flow model and the Reynolds-averaged N-S equation, we performed three-dimensional flow numerical simulation on the wellbore pump installation using commercial CFD software. Through the analysis of the performance curve, we found that the pump was more efficient when the diameter of the inlet pipe was larger. By comparing the loss of inlet water and outlet water, we found that the inlet water loss would increase with the flow rate, and the outlet water loss would first decrease and then increase with the increase of flow rate. By analyzing the VX cloud and flow graph, we found that when the diameter of the inlet pipe was relatively small, the flow velo city was relatively large, and the vortex was also large. The vorticity of the vortex was more than twice of that when the pipe diameter was large. Analysis on the distributio nuniformity of axial flow velocity at the impeller inlet section revealed that the flow velocity uniformity of the impeller inlet was relatively high when the inlet pipe was large, but the difference was not obvious when the flow rate exceeded 330 L/s. From the calculation of the average vorticity at the inlet section of the bell-tube, we found that the average vort icity at the bell-tube inlet section would increase with the flow rate, and it would decrease by more than20% when the inlet pipe diameter was large.
Based on the k-epsilon turbulent flow model and the Reynolds-averaged N-S equation, we performed three-dimensional flow numerical simulation on the wellbore pump installation using commercial CFD software. Through the analysis of the performance curve, we found that the pump was more efficient when the diameter of the inlet pipe was larger. By comparing the loss of inlet water and outlet water, we found that the inlet water loss would increase with the flow rate, and the outlet water loss would first decrease and then increase with the increase of flow rate. By analyzing the VX cloud and flow graph, we found that when the diameter of the inlet pipe was relatively small, the flow velo city was relatively large, and the vortex was also large. The vorticity of the vortex was more than twice of that when the pipe diameter was large. Analysis on the distributio nuniformity of axial flow velocity at the impeller inlet section revealed that the flow velocity uniformity of the impeller inlet was relatively high when the inlet pipe was large, but the difference was not obvious when the flow rate exceeded 330 L/s. From the calculation of the average vorticity at the inlet section of the bell-tube, we found that the average vort icity at the bell-tube inlet section would increase with the flow rate, and it would decrease by more than20% when the inlet pipe diameter was large.
2018, 16(2):196-201.
Abstract:
At present there is few research on the ultrasonic flow meter method for flow calculation. This paper presents a systematic study on this method. It elaborates on the ultrasonic flow meter method for flow calculation in terms of the principle of ultrasonic test, the calculation method for theoretical calibration coefficient k1 , the calculation method for channel cross-section area, and the calculation method for field calibration coefficient k2 . It puts forward the linear interpolation method for calculating theoretical calibration coefficient k1 . Taking the Yunhe station of the South-to-North Water Transfer Project as acase study , we used linear interpolation to calculate the theoretical calibration coefficient k1 , and calculated the flow by the ultrasonic flowmeter method. The calculation results were compared with the results of the current meter method. The comparison showed good consistency and controllable error. This study can provide a reference for engineering and technical personnel, provide important technical support to the localization of ultrasonic measurement devices, and provide technical support to the real-time on-line flow monitoring of key navigable channels and low velocity in China.
At present there is few research on the ultrasonic flow meter method for flow calculation. This paper presents a systematic study on this method. It elaborates on the ultrasonic flow meter method for flow calculation in terms of the principle of ultrasonic test, the calculation method for theoretical calibration coefficient k1 , the calculation method for channel cross-section area, and the calculation method for field calibration coefficient k2 . It puts forward the linear interpolation method for calculating theoretical calibration coefficient k1 . Taking the Yunhe station of the South-to-North Water Transfer Project as acase study , we used linear interpolation to calculate the theoretical calibration coefficient k1 , and calculated the flow by the ultrasonic flowmeter method. The calculation results were compared with the results of the current meter method. The comparison showed good consistency and controllable error. This study can provide a reference for engineering and technical personnel, provide important technical support to the localization of ultrasonic measurement devices, and provide technical support to the real-time on-line flow monitoring of key navigable channels and low velocity in China.
2018, 16(2):202-208.
Abstract:
A scientific and reasonable profit distribution mechanism is the key to the success of water diversion PPP project. Based on the basic principles of prof it distribution, we constructed an impact factor system of profit distribution with consideration to the features of water diversion PPP projects. Then, based on the Shapley value, we used the fuzzy synthetic method to determine the weight of each impact factor of profit distribution, and established an improved profit distribution model for water diversion PPP projects, so as to coordinate profit distribution and maximize profits for all stakeholders. Finally, we applied the model to an engineering case and verified the feasibility and validity of the model. The results showed that compared with the initial allocation scheme, the improved profit distribution mechanism not only can satisfy both individual rationality and group rationality, but also can measure the actual contribution of various stakeholders more truthfully. It does not affect the total profit of the water diversion PPP project, and only affects the distribution ratio between government, social capital, and franchise company of water diversion PPP project, whose profit distribution coefficients were 0.35, 0.41, and 0.24, respectively .
A scientific and reasonable profit distribution mechanism is the key to the success of water diversion PPP project. Based on the basic principles of prof it distribution, we constructed an impact factor system of profit distribution with consideration to the features of water diversion PPP projects. Then, based on the Shapley value, we used the fuzzy synthetic method to determine the weight of each impact factor of profit distribution, and established an improved profit distribution model for water diversion PPP projects, so as to coordinate profit distribution and maximize profits for all stakeholders. Finally, we applied the model to an engineering case and verified the feasibility and validity of the model. The results showed that compared with the initial allocation scheme, the improved profit distribution mechanism not only can satisfy both individual rationality and group rationality, but also can measure the actual contribution of various stakeholders more truthfully. It does not affect the total profit of the water diversion PPP project, and only affects the distribution ratio between government, social capital, and franchise company of water diversion PPP project, whose profit distribution coefficients were 0.35, 0.41, and 0.24, respectively .
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