Volume 12,Issue 3,2014 Table of Contents
2014, 12(3):1-4.
Abstract:
Based on the daily rainfall data at 61 stations in the Huang-Huai-Hai area from 1961 to 2010 and the data of《Tropical Cyclone Yearbook》, the frequency and intensity of tropical cyclone and tropical cyclone rainstorm were analyzed using the methods of regression analysis and ArcGIS spatial analysis. The results showed that the tropical cyclone in the Huang-Huai-Hai region usually lands intensely in the coastal place of Zhejiang and Fujian in August with the type of northward class path. Overall, the tropical cyclone rainstorm of the Huang-Huai-Hai area accounts for a small proportion of the total storm, but it has high intensity and the average amount of tropical cyclone rainstorm reaches 93.2 mm, which is similar to the heavy rainstorm. The temporal and spatial distribution of the frequency and amount of tropical cyclone rainstorm are both unbalanced. The frequency and intensity of tropical cyclone rainstorm in the Huang-Huai-Hai region increases in recent years, and the east coast and central and western regions?are most likely influenced by tropical cyclone with high frequency and heavy rainstorm. In addition, the frequency of tropical cyclone rainstorm shows a decreasing trend from east to west on the whole, but the distribution of rainstorm quantity is not apparent.
Based on the daily rainfall data at 61 stations in the Huang-Huai-Hai area from 1961 to 2010 and the data of《Tropical Cyclone Yearbook》, the frequency and intensity of tropical cyclone and tropical cyclone rainstorm were analyzed using the methods of regression analysis and ArcGIS spatial analysis. The results showed that the tropical cyclone in the Huang-Huai-Hai region usually lands intensely in the coastal place of Zhejiang and Fujian in August with the type of northward class path. Overall, the tropical cyclone rainstorm of the Huang-Huai-Hai area accounts for a small proportion of the total storm, but it has high intensity and the average amount of tropical cyclone rainstorm reaches 93.2 mm, which is similar to the heavy rainstorm. The temporal and spatial distribution of the frequency and amount of tropical cyclone rainstorm are both unbalanced. The frequency and intensity of tropical cyclone rainstorm in the Huang-Huai-Hai region increases in recent years, and the east coast and central and western regions?are most likely influenced by tropical cyclone with high frequency and heavy rainstorm. In addition, the frequency of tropical cyclone rainstorm shows a decreasing trend from east to west on the whole, but the distribution of rainstorm quantity is not apparent.
2014, 12(3):5-9.
Abstract:
Based on the precipitation, temperature, sunshine duration, mean wind speed, average relative humidity, and average vapor pressure data at 13 meteorological stations in the Western Route of South-to-North Water Diversion Project and adjacent regions over the past 60 years, the Mann-Kendall test, Hurst coefficient method, and wavelet method were used to perform the trend, continuity, and periodicity analysis on these meteorological factors. The results indicated that (1) the temperature at each station increases significantly, especially in the winter; (2) annual precipitation at 92% of total stations has an insignificant increasing trend, but precipitation has a significant increasing trend in the spring; and (3) annual sunshine duration at 64% of total stations shows a decreasing trend. Stations that have apparent variation trends of meteorological factors often belong to headwater catchment. Hurst coefficients of meteorological factors are were all greater than 0.5, which indicated a positive long-term continuity and that the variation trend in future is similar to that in the past. Morover, each meteorological factor sequence had an obvious cycle of 6 to 18 years.
Based on the precipitation, temperature, sunshine duration, mean wind speed, average relative humidity, and average vapor pressure data at 13 meteorological stations in the Western Route of South-to-North Water Diversion Project and adjacent regions over the past 60 years, the Mann-Kendall test, Hurst coefficient method, and wavelet method were used to perform the trend, continuity, and periodicity analysis on these meteorological factors. The results indicated that (1) the temperature at each station increases significantly, especially in the winter; (2) annual precipitation at 92% of total stations has an insignificant increasing trend, but precipitation has a significant increasing trend in the spring; and (3) annual sunshine duration at 64% of total stations shows a decreasing trend. Stations that have apparent variation trends of meteorological factors often belong to headwater catchment. Hurst coefficients of meteorological factors are were all greater than 0.5, which indicated a positive long-term continuity and that the variation trend in future is similar to that in the past. Morover, each meteorological factor sequence had an obvious cycle of 6 to 18 years.
2014, 12(3):10-16.
Abstract:
The unique characteristic time in a year, known as centroid time of annual precipitation, was introduced to solve the problem of identifying occurrence time of precipitation by frequency domain analysis. The centroid time is the time projection of annual precipitation process line and domain geotroid. The spatial, temporal, and frequency domain characteristics of centroid time of annual precipitation were analyzed to identify the spatial and temporal variations of precipitation quantitatively in China. The results suggested that (1) the centroid time is sensitive to the response of the occurrence time of heavy precipitation; (2) the spatial variation of centroid time is consistent with that of peak precipitation time of rainy season, showing “early-late-early” characteristics from northwest to southeast; (3) the time series of centroid time of the primary meteorological stations are pure random process with the non-random process is mainly shown at the stations located in central and northern China. The non-random characteristics are mainly periodicity, and the trend characteristics are mainly advanced trend; (4) the temporal distribution of precipitation grades are not even. The occurrence time of heavy precipitation is later than that of other precipitation grades, and the intra-annual distribution of moderate and light precipitation is the most unstable; and (5) the more uneven of intra-annual precipitation distribution , the more obvious of inter-annual variation of centroid time, indicating the unstable temporal distribution of precipitation in this area.
The unique characteristic time in a year, known as centroid time of annual precipitation, was introduced to solve the problem of identifying occurrence time of precipitation by frequency domain analysis. The centroid time is the time projection of annual precipitation process line and domain geotroid. The spatial, temporal, and frequency domain characteristics of centroid time of annual precipitation were analyzed to identify the spatial and temporal variations of precipitation quantitatively in China. The results suggested that (1) the centroid time is sensitive to the response of the occurrence time of heavy precipitation; (2) the spatial variation of centroid time is consistent with that of peak precipitation time of rainy season, showing “early-late-early” characteristics from northwest to southeast; (3) the time series of centroid time of the primary meteorological stations are pure random process with the non-random process is mainly shown at the stations located in central and northern China. The non-random characteristics are mainly periodicity, and the trend characteristics are mainly advanced trend; (4) the temporal distribution of precipitation grades are not even. The occurrence time of heavy precipitation is later than that of other precipitation grades, and the intra-annual distribution of moderate and light precipitation is the most unstable; and (5) the more uneven of intra-annual precipitation distribution , the more obvious of inter-annual variation of centroid time, indicating the unstable temporal distribution of precipitation in this area.
2014, 12(3):17-23.
Abstract:
Due to the complex terrain changes and characteristics of Nansi Lake Basin, the reliability of water transfer project can be affected if the traditional one-dimensional total flow method is used in the hydraulic calculation of dredging project in the lake. In this study, a depth-averaged two-dimensional mathematical flow model system of Nansi Lake was created and verified on the basis of 1/10000 scale topographic map (CAD version) and satellite remote sensing images of Nansi Lake. Under the conditions of design water transfer scheme, the flow fields of the upper and lower Nansi Lake were simulated using the two-dimensional mathematical model. The dredging program with the smallest amount of excavation was determined in order to meet the requirements of water level at control locations under both normal design and special drought conditions. Analysis of the flow field results indicated that the flow field in the whole lake, both in the upper and lower lakes, showed solo-directional feature from south to north during the process of water transfer. The average flow velocity in the main channel was 0.12 m/s, generally about one order of magnitude higher than that in the non-main channel regions. The main channel of Nansi Lake played the major role in water transfer as its average flow rate accounted for 61.5% of the total flow rate and its maximum capability can reach 88.9%.
Due to the complex terrain changes and characteristics of Nansi Lake Basin, the reliability of water transfer project can be affected if the traditional one-dimensional total flow method is used in the hydraulic calculation of dredging project in the lake. In this study, a depth-averaged two-dimensional mathematical flow model system of Nansi Lake was created and verified on the basis of 1/10000 scale topographic map (CAD version) and satellite remote sensing images of Nansi Lake. Under the conditions of design water transfer scheme, the flow fields of the upper and lower Nansi Lake were simulated using the two-dimensional mathematical model. The dredging program with the smallest amount of excavation was determined in order to meet the requirements of water level at control locations under both normal design and special drought conditions. Analysis of the flow field results indicated that the flow field in the whole lake, both in the upper and lower lakes, showed solo-directional feature from south to north during the process of water transfer. The average flow velocity in the main channel was 0.12 m/s, generally about one order of magnitude higher than that in the non-main channel regions. The main channel of Nansi Lake played the major role in water transfer as its average flow rate accounted for 61.5% of the total flow rate and its maximum capability can reach 88.9%.
2014, 12(3):24-28.
Abstract:
The geothermal reservoir in the southern area of Gaoqing County consists mainly of two formations: Neogene Guantao Formation and Palaeogene Dongying Formation. According to the field observation and laboratory analyses，reasonable parameters were selected to develop the geothermal reservoir concept model. On the basis, the heat reservoir method and recovery rate method were used to calculate and evaluate the total and available geothermal resources in the study area, respectively, and the volume method and maximum drawdown method were used to evaluate the storage capacity and allowable withdrawal of underground hot water resources. The results showed that the total geothermal resources quantity is 2.5161 x 1018 J, equal to 8.587 x 107 t of standard coal, and the available geothermal resources is 6.290×1017J, equal to 2.147×107t of standard coal (recovery rate is 25%). Also, the underground hot water storage capacity is 6.542 x 109 m3, and the allowable withdrawal is 3.833 x 106 m3/a based on a production life of 100 years.
The geothermal reservoir in the southern area of Gaoqing County consists mainly of two formations: Neogene Guantao Formation and Palaeogene Dongying Formation. According to the field observation and laboratory analyses，reasonable parameters were selected to develop the geothermal reservoir concept model. On the basis, the heat reservoir method and recovery rate method were used to calculate and evaluate the total and available geothermal resources in the study area, respectively, and the volume method and maximum drawdown method were used to evaluate the storage capacity and allowable withdrawal of underground hot water resources. The results showed that the total geothermal resources quantity is 2.5161 x 1018 J, equal to 8.587 x 107 t of standard coal, and the available geothermal resources is 6.290×1017J, equal to 2.147×107t of standard coal (recovery rate is 25%). Also, the underground hot water storage capacity is 6.542 x 109 m3, and the allowable withdrawal is 3.833 x 106 m3/a based on a production life of 100 years.
2014, 12(3):29-32.
Abstract:
The monthly streamflow data at 3 stations and monthly precipitation data at 20 stations of 40 years (1970 to 2009) in the Nanpan River Basin were selected to calculate the standardized streamflow index (SSFI) and standardized precipitation index (SPI) of different time scales (3,6,9,12,24 months). The SSFI for the hydrological drought samples from the computing results and SPI of the same period were selected to perform statistical analysis and then to investigate the response of hydrological droughts to climatic droughts. The results showed that (1) SSFI has good response to the SPI in the Nanpan River Basin; (2) the correlation between SSFI and SPI varies with time scale; and (3) the response time of hydrological droughts to climatic droughts is about 6 months in general.
The monthly streamflow data at 3 stations and monthly precipitation data at 20 stations of 40 years (1970 to 2009) in the Nanpan River Basin were selected to calculate the standardized streamflow index (SSFI) and standardized precipitation index (SPI) of different time scales (3,6,9,12,24 months). The SSFI for the hydrological drought samples from the computing results and SPI of the same period were selected to perform statistical analysis and then to investigate the response of hydrological droughts to climatic droughts. The results showed that (1) SSFI has good response to the SPI in the Nanpan River Basin; (2) the correlation between SSFI and SPI varies with time scale; and (3) the response time of hydrological droughts to climatic droughts is about 6 months in general.
2014, 12(3):33-37.
Abstract:
Using thermal inertia method, ATI-SWC experience model of Guanzhong area was established, combined the same time soil moisture data measured at weather station and temperature difference of day and night and reflectivity obtained based on three phrase Terro-MODIS1B data in spring of 2009. The results showed that the model of March 3 had high precision and the model of April 28 has lowest precision. NDVIs of the three time were analyzed and NDVI affected model precision greatly, so thermal inertia method had higher precision on monitoring soil moisture of bare land. Finally, together with DEM，influences from geology, geomorphology and NDVI to soil moisture in Guanzhong were comprehensive analyzed. Results had some reference value on drought monitoring of Guanzhong.
Using thermal inertia method, ATI-SWC experience model of Guanzhong area was established, combined the same time soil moisture data measured at weather station and temperature difference of day and night and reflectivity obtained based on three phrase Terro-MODIS1B data in spring of 2009. The results showed that the model of March 3 had high precision and the model of April 28 has lowest precision. NDVIs of the three time were analyzed and NDVI affected model precision greatly, so thermal inertia method had higher precision on monitoring soil moisture of bare land. Finally, together with DEM，influences from geology, geomorphology and NDVI to soil moisture in Guanzhong were comprehensive analyzed. Results had some reference value on drought monitoring of Guanzhong.
2014, 12(3):38-41.
Abstract:
In this study, the long-term trends of monthly temperature and precipitation from 1970 to 2009 and annual runoff data from 1961 to 2008 in the Longchuan River Basin were analyzed using the non-parametric Mann-Kendall method. In addition, the R/S method was used to investigate the continuity of the time series data of annual temperature, precipitation, and runoff in the basin and to estimate the Hurst exponent for each index, which can be used to estimate the variation trends of temperature, precipitation, and runoff quantitatively. The results showed that (1) precipitation has an insignificant increasing trend in the basin and it will continue to increase, especially at Yuanmou station; (2) temperature has a significant increasing trend in the basin and it will continue to increase; and (3) runoff has an insignificant decreasing trend in the basin and it will continue to decrease but without strong continuity.
In this study, the long-term trends of monthly temperature and precipitation from 1970 to 2009 and annual runoff data from 1961 to 2008 in the Longchuan River Basin were analyzed using the non-parametric Mann-Kendall method. In addition, the R/S method was used to investigate the continuity of the time series data of annual temperature, precipitation, and runoff in the basin and to estimate the Hurst exponent for each index, which can be used to estimate the variation trends of temperature, precipitation, and runoff quantitatively. The results showed that (1) precipitation has an insignificant increasing trend in the basin and it will continue to increase, especially at Yuanmou station; (2) temperature has a significant increasing trend in the basin and it will continue to increase; and (3) runoff has an insignificant decreasing trend in the basin and it will continue to decrease but without strong continuity.
2014, 12(3):42-46.
Abstract:
With the rapidly economic and social development and population increase, the impacts of human activities aggravate in the Haihe River Basin, resulting in significant changes in the underlying surface conditions. Based on the hydrological data in detail in the Haihe River Basin, the statistical analysis and Mann Kendall rank correlation test were used to analyze the variation rule and trend of storm flood in the Haihe River Basin under the conditions of human activities and climate changes. The results suggested that storm flood has a decreasing trend in the basin. Research results can lay the foundations for the consistency correction of flood series and provide technical support for the planning and management of flood control and drought relief in the basin.
With the rapidly economic and social development and population increase, the impacts of human activities aggravate in the Haihe River Basin, resulting in significant changes in the underlying surface conditions. Based on the hydrological data in detail in the Haihe River Basin, the statistical analysis and Mann Kendall rank correlation test were used to analyze the variation rule and trend of storm flood in the Haihe River Basin under the conditions of human activities and climate changes. The results suggested that storm flood has a decreasing trend in the basin. Research results can lay the foundations for the consistency correction of flood series and provide technical support for the planning and management of flood control and drought relief in the basin.
2014, 12(3):47-50.
Abstract:
In order to investigate the water salinization mechanism in Beidagang reservoir of Tianjin, field sampling method and laboratory column experiment were conducted to examine the rule of salt release between the bed sediment and overlying water body under reservoir filling. The results showed that (1) a salinity variation zone (diffusion boundary layer) exists in the water body of 10 cm above the sediment and water interface when salt is released from bed sediment. About 60% of the total released salt accumulates in the diffusion boundary layer, and the vertical variation of water salinity is insignificant above the diffusion boundary layer; (2) the accumulative amount of salt released from the bed sediment conforms to the form of logarithmic function with time, and the accumulative amount of released salt in the first 50 days of the experiment can reach 80% of the total amount; and (3) the variation of salt flux at the sediment and water interface shows periodic characteristics with a rapidly initial increasing and then a slow decline within each period.
In order to investigate the water salinization mechanism in Beidagang reservoir of Tianjin, field sampling method and laboratory column experiment were conducted to examine the rule of salt release between the bed sediment and overlying water body under reservoir filling. The results showed that (1) a salinity variation zone (diffusion boundary layer) exists in the water body of 10 cm above the sediment and water interface when salt is released from bed sediment. About 60% of the total released salt accumulates in the diffusion boundary layer, and the vertical variation of water salinity is insignificant above the diffusion boundary layer; (2) the accumulative amount of salt released from the bed sediment conforms to the form of logarithmic function with time, and the accumulative amount of released salt in the first 50 days of the experiment can reach 80% of the total amount; and (3) the variation of salt flux at the sediment and water interface shows periodic characteristics with a rapidly initial increasing and then a slow decline within each period.
2014, 12(3):51-54.
Abstract:
In this paper, the multi-index comprehensive evaluation method was used to evaluate the water quality of Erhe drinking water source region of Huaian city in 2012, and the results showed that the current water quality meets the standards of drinking water. The risk scales of water pollutants on public health were assessed using the Water Environmental Health Risk Assessment Model of U.S.EPA, which indicated that the personal annual risk caused by the chemical carcinogens through drinking water is much greater than that by the non-carcinogenic substances, and the order of risk scales for all pollutants is As>Pb >Fluoride>Nitrate>Mn >Fe>NH3-N. The research results can provide technical support for the water quality management of Erhe drinking water source region.
In this paper, the multi-index comprehensive evaluation method was used to evaluate the water quality of Erhe drinking water source region of Huaian city in 2012, and the results showed that the current water quality meets the standards of drinking water. The risk scales of water pollutants on public health were assessed using the Water Environmental Health Risk Assessment Model of U.S.EPA, which indicated that the personal annual risk caused by the chemical carcinogens through drinking water is much greater than that by the non-carcinogenic substances, and the order of risk scales for all pollutants is As>Pb >Fluoride>Nitrate>Mn >Fe>NH3-N. The research results can provide technical support for the water quality management of Erhe drinking water source region.
2014, 12(3):55-58.
Abstract:
In this study, the matter-element analysis theory was used to expand the single policy decision problem into a multi-dimensional matter-element structure, and the calculation of the distance of point and interval in the traditional matter-element model was improved. The entropy method was used to determine the weight of each index, and an improved multi-dimensional matter-element model of water quality assessment was developed. The improved matter-element model was used to evaluate the water quality in the Beizhijiang Drainage Basin of Guangxi. The water quality data in 2011 were collected, and five typical sections and eight water quality assessment indexes were selected. The results showed that class II water is in the upstream of Beizhijiang Drainage Basin , whereas class III water in the midstream and downstream. The results were in accordance with water function zonation in Laibin city, indicating that the improved matter-element method is reliable for quality assessment.
In this study, the matter-element analysis theory was used to expand the single policy decision problem into a multi-dimensional matter-element structure, and the calculation of the distance of point and interval in the traditional matter-element model was improved. The entropy method was used to determine the weight of each index, and an improved multi-dimensional matter-element model of water quality assessment was developed. The improved matter-element model was used to evaluate the water quality in the Beizhijiang Drainage Basin of Guangxi. The water quality data in 2011 were collected, and five typical sections and eight water quality assessment indexes were selected. The results showed that class II water is in the upstream of Beizhijiang Drainage Basin , whereas class III water in the midstream and downstream. The results were in accordance with water function zonation in Laibin city, indicating that the improved matter-element method is reliable for quality assessment.
2014, 12(3):59-64.
Abstract:
Based on the remote sensing images of Hetao Plainin 2000 and 2006, the dynamic variation of salinization land was analyzed using the combination of remote sensing and GIS technology and statistics and spatial analysis. The results showed that the salinization land area has reduced significantly in the study area from 2000 to 2006 with an average annual decreasing rate of 5.34%. The levels of light and medium salinization land have reduced. The ratio of light salinization land to the total land decreased from 10.35% to 6.82%, and the ratio of medium salinization land to the total land decreased from 4.67% down to 1.94%. However, the heavy salinization land level has not changed significantly with the ratio varying from 5.15% to 4.96%. Soil salinization is affected by the natural environment (regional evaporation to precipitation ratio, groundwater depth, and vadose zone lithology) and human activities, , but it does not have an obvious relationship with groundwater salinity.
Based on the remote sensing images of Hetao Plainin 2000 and 2006, the dynamic variation of salinization land was analyzed using the combination of remote sensing and GIS technology and statistics and spatial analysis. The results showed that the salinization land area has reduced significantly in the study area from 2000 to 2006 with an average annual decreasing rate of 5.34%. The levels of light and medium salinization land have reduced. The ratio of light salinization land to the total land decreased from 10.35% to 6.82%, and the ratio of medium salinization land to the total land decreased from 4.67% down to 1.94%. However, the heavy salinization land level has not changed significantly with the ratio varying from 5.15% to 4.96%. Soil salinization is affected by the natural environment (regional evaporation to precipitation ratio, groundwater depth, and vadose zone lithology) and human activities, , but it does not have an obvious relationship with groundwater salinity.
2014, 12(3):65-68.
Abstract:
Based on the lithological and hydrological characteristics at a typical petroleum contaminated site, and data collection and analysis of long-term observation and water pumping and dispersion experiments, a numerical model of groundwater flow and solute transport was developed and verified by a flow model. BTEX was used as the simulation factor, the convection - diffusion solute transport process in groundwater was simulated using MT3DMS module of GMS software, and the organic pollutant biodegradation process with the coexistence of a variety of mobile or immobile microorganisms in groundwater was simulated using RT3D module of GMS software. The results showed that chemical reactions of biodegradation can decrease the peak values of contamination, and a large amount of aerobic microbes and denitrification exist in the study area, which suggested that in-situ bioremediation can be used to control petroleum pollution.
Based on the lithological and hydrological characteristics at a typical petroleum contaminated site, and data collection and analysis of long-term observation and water pumping and dispersion experiments, a numerical model of groundwater flow and solute transport was developed and verified by a flow model. BTEX was used as the simulation factor, the convection - diffusion solute transport process in groundwater was simulated using MT3DMS module of GMS software, and the organic pollutant biodegradation process with the coexistence of a variety of mobile or immobile microorganisms in groundwater was simulated using RT3D module of GMS software. The results showed that chemical reactions of biodegradation can decrease the peak values of contamination, and a large amount of aerobic microbes and denitrification exist in the study area, which suggested that in-situ bioremediation can be used to control petroleum pollution.
2014, 12(3):69-72.
Abstract:
According to the characteristics of PCCP pipeline project and environmental characteristics of area where the pipeline crosses over, the vegetation restoration area of PCCP project in Beijing section of South-to-North Water Transfer Project was investigated to determine the configuration modes of different vegetation restoration measures and the diversity and biomass of herbs using the field investigation and laboratory analysis. The results showed that (1) the engineering greening mode can achieve good restoration effects within a short time, whereas the diversity and biomass of herbs are high for both stratified and mixed modes; (2) the fencing mode can result in high biomass but low diversity of herbs; and (3) the rehabilitation mode can lead to relatively even and stable diversity index and biomass of herbs.
According to the characteristics of PCCP pipeline project and environmental characteristics of area where the pipeline crosses over, the vegetation restoration area of PCCP project in Beijing section of South-to-North Water Transfer Project was investigated to determine the configuration modes of different vegetation restoration measures and the diversity and biomass of herbs using the field investigation and laboratory analysis. The results showed that (1) the engineering greening mode can achieve good restoration effects within a short time, whereas the diversity and biomass of herbs are high for both stratified and mixed modes; (2) the fencing mode can result in high biomass but low diversity of herbs; and (3) the rehabilitation mode can lead to relatively even and stable diversity index and biomass of herbs.
2014, 12(3):73-76.
Abstract:
River health assessment plays an important role in guiding the control and protection of river environment. In this paper, fuzzy hierarchy analysis was used to determine the weight of each index in the river health system, and variable fuzzy set theory was introduced to establish an integrated model of fuzzy analytical hierarchy process and variable fuzzy set (FAHP-VFS). The model was applied in the Nanchuan River. Twenty quantitative and qualitative indexes were selected to develop the river health evaluation system, and river health was evaluated from three aspects including geomorphology, ecology, and hydrology. The results showed that the overall Nanchuan River is in a healthy state, but some segments are in a sub-healthy state, which suggested that the Nanchuan River needs sectionalized regulations.
River health assessment plays an important role in guiding the control and protection of river environment. In this paper, fuzzy hierarchy analysis was used to determine the weight of each index in the river health system, and variable fuzzy set theory was introduced to establish an integrated model of fuzzy analytical hierarchy process and variable fuzzy set (FAHP-VFS). The model was applied in the Nanchuan River. Twenty quantitative and qualitative indexes were selected to develop the river health evaluation system, and river health was evaluated from three aspects including geomorphology, ecology, and hydrology. The results showed that the overall Nanchuan River is in a healthy state, but some segments are in a sub-healthy state, which suggested that the Nanchuan River needs sectionalized regulations.
2014, 12(3):77-80.
Abstract:
The pressure pipe of high-lift pump station can have structural damages due to flow-induced vibration, and the mean control chart method based on the statistical pattern theory was proposed to identify the damage. First, the response information of the measured data was obtained under the normal and to-be-detected conditions, which can be used to develop the system model for damage diagnosis. Then, statistical calculations were performed on numerous data information to extract the eigenvalue and optimize the eigenvector. Finally, the mean control chart method was used to identify the damage in the pressure pipe of the pump station. The results showed that the mean control chart method can identify any damage in the pressure pipe intuitively and accurately, and therefore it can be used as an important method for damage identification of pressure pipe of pump station.
The pressure pipe of high-lift pump station can have structural damages due to flow-induced vibration, and the mean control chart method based on the statistical pattern theory was proposed to identify the damage. First, the response information of the measured data was obtained under the normal and to-be-detected conditions, which can be used to develop the system model for damage diagnosis. Then, statistical calculations were performed on numerous data information to extract the eigenvalue and optimize the eigenvector. Finally, the mean control chart method was used to identify the damage in the pressure pipe of the pump station. The results showed that the mean control chart method can identify any damage in the pressure pipe intuitively and accurately, and therefore it can be used as an important method for damage identification of pressure pipe of pump station.
2014, 12(3):81-84.
Abstract:
The retaining wall composed of soil bag has certain flexibility and can have lateral distortion under the pressure, which can reduce the pressure effectively and increase the safety of retaining wall. Earth pressure is an important load for the section design and stability check of retaining structures, and it is directly relevant to the wall displacement mode. A model test was performed on a retaining wall constructed with soilbags, which showed that (1) the deformation mode of the wall and the failure mode of the backfill soil are composed of translational and rotary modes; (2) The vertical distribution of earth pressure of the retaining wall composed of soilbags is close to Coulomb active earth pressure; and (3) the earth pressure decreases from the inside out along the horizontal direction. A force balance equation was established to explain the horizontal decreasing of the earth pressures within the retaining wall.
The retaining wall composed of soil bag has certain flexibility and can have lateral distortion under the pressure, which can reduce the pressure effectively and increase the safety of retaining wall. Earth pressure is an important load for the section design and stability check of retaining structures, and it is directly relevant to the wall displacement mode. A model test was performed on a retaining wall constructed with soilbags, which showed that (1) the deformation mode of the wall and the failure mode of the backfill soil are composed of translational and rotary modes; (2) The vertical distribution of earth pressure of the retaining wall composed of soilbags is close to Coulomb active earth pressure; and (3) the earth pressure decreases from the inside out along the horizontal direction. A force balance equation was established to explain the horizontal decreasing of the earth pressures within the retaining wall.
2014, 12(3):85-88.
Abstract:
The dynamic response of the dam-structure interaction system under the action of earthquake and wind was analyzed based on VOF method. Under the three working conditions of empty reservoir, dam-reservoir interaction, and dam-water-wind interaction, the dynamic displacement, absolute acceleration, and hydrodynamic response of the dam under the earthquake and wind load were calculated and analyzed. Meanwhile, the tracking of free surface based on VOF method verified its reliability and superiority. The results indicated that the interaction between the reservoir and dam is remarkably nonlinear. The dynamic displacement and absolute acceleration can be increased by the dam-water interaction. Furthermore, wind had no impacts on the dynamic displacement and absolute acceleration of the dam, but significant impacts on hydrodynamic pressure.
The dynamic response of the dam-structure interaction system under the action of earthquake and wind was analyzed based on VOF method. Under the three working conditions of empty reservoir, dam-reservoir interaction, and dam-water-wind interaction, the dynamic displacement, absolute acceleration, and hydrodynamic response of the dam under the earthquake and wind load were calculated and analyzed. Meanwhile, the tracking of free surface based on VOF method verified its reliability and superiority. The results indicated that the interaction between the reservoir and dam is remarkably nonlinear. The dynamic displacement and absolute acceleration can be increased by the dam-water interaction. Furthermore, wind had no impacts on the dynamic displacement and absolute acceleration of the dam, but significant impacts on hydrodynamic pressure.
2014, 12(3):89-94.
Abstract:
The flow field of a new T-shaped stirrer was simulated using the multiple reference frame (MRF) method in the computational fluid dynamics (CFD) software FLUENT. The intensity of turbulence, flow field characteristics, mean velocity distribution, and mixing power of the T-shaped stirrer, open turbine stirrer, and rushton turbine stirrer were analyzed and compared, and the results suggested that the T-shaped stirrer has a better flow field distribution to achieve better mixing effects. The mixing characteristics of T-shaped stirrer with different mounting heights were analyzed, and the best mounting height was obtained as 150mm under the condition of fixed stirred tank size. The turbulence intensity and mixing power of the T-shaped stirrer with different numbers of blades were investigated, which showed that the mixing power increases with the increasing number of blades and the T-shaped stirrer with 3 blades has the best turbulence intensity distribution. The research can provide an important basis for the analysis and development of new stirrer.
The flow field of a new T-shaped stirrer was simulated using the multiple reference frame (MRF) method in the computational fluid dynamics (CFD) software FLUENT. The intensity of turbulence, flow field characteristics, mean velocity distribution, and mixing power of the T-shaped stirrer, open turbine stirrer, and rushton turbine stirrer were analyzed and compared, and the results suggested that the T-shaped stirrer has a better flow field distribution to achieve better mixing effects. The mixing characteristics of T-shaped stirrer with different mounting heights were analyzed, and the best mounting height was obtained as 150mm under the condition of fixed stirred tank size. The turbulence intensity and mixing power of the T-shaped stirrer with different numbers of blades were investigated, which showed that the mixing power increases with the increasing number of blades and the T-shaped stirrer with 3 blades has the best turbulence intensity distribution. The research can provide an important basis for the analysis and development of new stirrer.
2014, 12(3):95-98.
Abstract:
In this paper, computational fluid dynamics (CFD) method was used to simulate several typical working conditions of tailrace surge tanks shared by two units. The flow velocity distribution under the surge tank, head loss, and flow rate of water flowing into or out of the surge tank through the two impedance holes were obtained and analyzed. In addition, the simulated flow patterns under different working conditions were analyzed and compared with those obtained from experimental results. The results indicated that the head loss coefficient for water flowing into or out of the surge tank increases with the increasing of flow rate and the head loss coefficient under single-unit operation is lower than that under two-unit operation. Moreover, the flow rates of water flowing into or out of the surge tank through the two impedance holes shared by two units were not the same under single-unit operation and they were affected by the variation of discharge ratio.
In this paper, computational fluid dynamics (CFD) method was used to simulate several typical working conditions of tailrace surge tanks shared by two units. The flow velocity distribution under the surge tank, head loss, and flow rate of water flowing into or out of the surge tank through the two impedance holes were obtained and analyzed. In addition, the simulated flow patterns under different working conditions were analyzed and compared with those obtained from experimental results. The results indicated that the head loss coefficient for water flowing into or out of the surge tank increases with the increasing of flow rate and the head loss coefficient under single-unit operation is lower than that under two-unit operation. Moreover, the flow rates of water flowing into or out of the surge tank through the two impedance holes shared by two units were not the same under single-unit operation and they were affected by the variation of discharge ratio.
2014, 12(3):99-103.
Abstract:
A three-dimensional finite element model of cast iron gate in a hydraulic project was developed using ANSYS software. Under the working conditions that the forward and reverse head difference was 10 m, the maximum stress and deformation were calculated and analyzed using the thin plate theory and three-dimensional finite element method. The results showed that the errors of maximum stress and deformation are as high as 30%-50% for the two methods. The calculation results obtained from the traditional empirical formula were more conservative, which can cause the increasing of manufacturing cost of cast iron gate, especially when the maximum stress and deformation were not at the same place under reverse head. There were deficiencies in analyzing the allowable stress intensity and stiffness required by relative standards according to the compression/tensile strength of the cast iron gate material and the stress and deformation variations of gate under inverse/reverse force. In this paper, the optimization scheme of arrangement type and section size of the gate was proposed in order to reduce the manufacturing cost.
A three-dimensional finite element model of cast iron gate in a hydraulic project was developed using ANSYS software. Under the working conditions that the forward and reverse head difference was 10 m, the maximum stress and deformation were calculated and analyzed using the thin plate theory and three-dimensional finite element method. The results showed that the errors of maximum stress and deformation are as high as 30%-50% for the two methods. The calculation results obtained from the traditional empirical formula were more conservative, which can cause the increasing of manufacturing cost of cast iron gate, especially when the maximum stress and deformation were not at the same place under reverse head. There were deficiencies in analyzing the allowable stress intensity and stiffness required by relative standards according to the compression/tensile strength of the cast iron gate material and the stress and deformation variations of gate under inverse/reverse force. In this paper, the optimization scheme of arrangement type and section size of the gate was proposed in order to reduce the manufacturing cost.
2014, 12(3):104-107.
Abstract:
Based on the N-S equation, turbulent model, and periodic boundary, CFD numerical calculation and analysis was performed on the tank of thrust bearing under the rated speed with different oil film thicknesses and tile surface angles. The 1/12 model of the thrust tank was established using the tool of Autocad and Proe and the computational domain was discretized using the clumpy gridding technology. SIMPLEC algorithm in Fluent was used to perform the simulation. The calculation results were post-processed to determine the pressure distribution of tile surface, the relation curves between oil film thickness, tile surface angle, and bearing capacity of tile surface, and the velocity distribution with different thicknesses of oil film, which can better guide the design, maintenance, and operation of thrust bearing.
Based on the N-S equation, turbulent model, and periodic boundary, CFD numerical calculation and analysis was performed on the tank of thrust bearing under the rated speed with different oil film thicknesses and tile surface angles. The 1/12 model of the thrust tank was established using the tool of Autocad and Proe and the computational domain was discretized using the clumpy gridding technology. SIMPLEC algorithm in Fluent was used to perform the simulation. The calculation results were post-processed to determine the pressure distribution of tile surface, the relation curves between oil film thickness, tile surface angle, and bearing capacity of tile surface, and the velocity distribution with different thicknesses of oil film, which can better guide the design, maintenance, and operation of thrust bearing.
2014, 12(3):108-111.
Abstract:
shaped tube has been widely used recently，but complex stress distribution in the pipeline has bought a lot of problems for design and construction。It often occurs the pipe cracking in the practicle, which causes many negative effects such as water and electricity discountinued.so it is necessary to carry out computer simulation analysis before design and construction. It has been simulation analysised with the finite element analysis software fluent。It had studied pipeline internal fluid velocity and pressure distribution of shaped pipe in the case of steady flow and unsteady flow。The simulation results show that fluid velocity of steady flow show maximum value in the middle of variable diameter pipe and pressure minimum, and for unsteady flow in the entrance, pressure maximumin the transition segment one-third.in the entrance section pressure is the first small to big and small，but it is big then small big in the exit。
shaped tube has been widely used recently，but complex stress distribution in the pipeline has bought a lot of problems for design and construction。It often occurs the pipe cracking in the practicle, which causes many negative effects such as water and electricity discountinued.so it is necessary to carry out computer simulation analysis before design and construction. It has been simulation analysised with the finite element analysis software fluent。It had studied pipeline internal fluid velocity and pressure distribution of shaped pipe in the case of steady flow and unsteady flow。The simulation results show that fluid velocity of steady flow show maximum value in the middle of variable diameter pipe and pressure minimum, and for unsteady flow in the entrance, pressure maximumin the transition segment one-third.in the entrance section pressure is the first small to big and small，but it is big then small big in the exit。
2014, 12(3):112-115.
Abstract:
The turbine with super low specific speed and a flow rate of 5000 t/h used in a cooling tower was investigated through structural design in order to develop a new type of small Francis turbine that can match fan directly and recover the surplus energy from cooling tower. On the basis of Reynolds time-averaged N-S equation, RNG k-ε turbulent model, and SIMPLC algorithm, the three-dimensional steady turbulent flow in the designed turbine model was simulated numerically using the commercial CFD software Fluent, and the flow field in the turbine and hydraulic loss of each component were analyzed. The results showed that the output power of turbine is 143.3 kW and the efficiency is 83.74% with a small head loss under the design conditions. When the redundant head was in the range of 12 to 14 m, the turbine had a good flow state and stable hydraulic performance with the efficiency of above 83%, which indicated that the turbine meets the design requirements.
The turbine with super low specific speed and a flow rate of 5000 t/h used in a cooling tower was investigated through structural design in order to develop a new type of small Francis turbine that can match fan directly and recover the surplus energy from cooling tower. On the basis of Reynolds time-averaged N-S equation, RNG k-ε turbulent model, and SIMPLC algorithm, the three-dimensional steady turbulent flow in the designed turbine model was simulated numerically using the commercial CFD software Fluent, and the flow field in the turbine and hydraulic loss of each component were analyzed. The results showed that the output power of turbine is 143.3 kW and the efficiency is 83.74% with a small head loss under the design conditions. When the redundant head was in the range of 12 to 14 m, the turbine had a good flow state and stable hydraulic performance with the efficiency of above 83%, which indicated that the turbine meets the design requirements.
2014, 12(3):116-120.
Abstract:
Based on the analysis of coordination relationship between the interconnected river system network and socio-economic development, an index system to evaluate the coordination of the two systems was developed. The combination method of analytic hierarchy process and entropy value method was used to determine the weight of each index. On the basis of the calculation formula of matching degree, the calculation method of coordination degree between the interconnected river system network and socio-economic development was proposed. In this paper, this calculation method was applied to determine the coordination degree and level between the interconnected river system network and socio-economic development in Zhengzhou from 2003 to 2011, and the variation of coordination degree in the past years was analyzed. The research is aimed at providing guidance and reference to the strategic study of interconnected river system network and socio-economic development.
Based on the analysis of coordination relationship between the interconnected river system network and socio-economic development, an index system to evaluate the coordination of the two systems was developed. The combination method of analytic hierarchy process and entropy value method was used to determine the weight of each index. On the basis of the calculation formula of matching degree, the calculation method of coordination degree between the interconnected river system network and socio-economic development was proposed. In this paper, this calculation method was applied to determine the coordination degree and level between the interconnected river system network and socio-economic development in Zhengzhou from 2003 to 2011, and the variation of coordination degree in the past years was analyzed. The research is aimed at providing guidance and reference to the strategic study of interconnected river system network and socio-economic development.
2014, 12(3):121-126.
Abstract:
River flow and bed deformation in meandering streams are more complex than those in straight rivers, which is one of the main subjects in river dynamics. In recent years, with the rapid development of computer hardware and software and the appearance of efficient numerical methods as well, numerical simulation of meandering river flow and sediment transport develops with greater progress. This paper summarized the properties of meandering flow, such as the lateral slope of water surface, transverse circulation, average velocity along vertical line, and bed shear stress, and the basic characteristics of sediment transport. In addition, the research progress on the two-dimensional and three-dimensional flow models and bed evolution models in meandering streams were reviewed. The exiting problems of current numerical simulation on meandering river flow and sediment transport were pointed out and some possible solutions for future research in meandering river flow and bed deformation were proposed.
River flow and bed deformation in meandering streams are more complex than those in straight rivers, which is one of the main subjects in river dynamics. In recent years, with the rapid development of computer hardware and software and the appearance of efficient numerical methods as well, numerical simulation of meandering river flow and sediment transport develops with greater progress. This paper summarized the properties of meandering flow, such as the lateral slope of water surface, transverse circulation, average velocity along vertical line, and bed shear stress, and the basic characteristics of sediment transport. In addition, the research progress on the two-dimensional and three-dimensional flow models and bed evolution models in meandering streams were reviewed. The exiting problems of current numerical simulation on meandering river flow and sediment transport were pointed out and some possible solutions for future research in meandering river flow and bed deformation were proposed.
2014, 12(3):127-132.
Abstract:
Groundwater resources play an important role in urban water supply in China. However, groundwater has been increasingly polluted recently, thus risk assessment of groundwater pollution is indispensable as the risk assessment results could guide the prevention and control of groundwater pollution. In this paper, the development process of the concept of groundwater pollution risk and assessment methods was reviewed as well as the specific steps and contents for the development of assessment system. Based on the currently available theories, the main components of groundwater pollution risk assessment, including the intrinsic vulnerability assessment, stress vulnerability assessment, and groundwater value assessment, were demonstrated and summarized, and the verification methods of groundwater pollution risk assessment were also introduced. Finally, the existing problems in the current groundwater pollution risk assessment research were discussed from the perspectives of model applicability, data comprehensiveness, timeliness of the results, and rationality of the factors. In addition, some directional suggestions were proposed for further research.
Groundwater resources play an important role in urban water supply in China. However, groundwater has been increasingly polluted recently, thus risk assessment of groundwater pollution is indispensable as the risk assessment results could guide the prevention and control of groundwater pollution. In this paper, the development process of the concept of groundwater pollution risk and assessment methods was reviewed as well as the specific steps and contents for the development of assessment system. Based on the currently available theories, the main components of groundwater pollution risk assessment, including the intrinsic vulnerability assessment, stress vulnerability assessment, and groundwater value assessment, were demonstrated and summarized, and the verification methods of groundwater pollution risk assessment were also introduced. Finally, the existing problems in the current groundwater pollution risk assessment research were discussed from the perspectives of model applicability, data comprehensiveness, timeliness of the results, and rationality of the factors. In addition, some directional suggestions were proposed for further research.
2014, 12(3):133-137.
Abstract:
In order to improve the precision of groundwater solute transport model and reduce the errors caused by the uncertainties of hydrogeological parameters, sensitivity analysis of parameters is needed for the numerical model. In this paper, a groundwater flow and solute transport model was established to simulate the pore water in an alluvial fan plain using GMS 7.0, and the model was verified. Sensitivity index was introduced to quantify parameter sensitivity. Factor transformation method, known as a local analysis method, was used to perform sensitivity analysis of permeability coefficient, porosity, and dispersity. Variation range of the parameters was set to be 20%. The results showed that (1) permeability coefficient and porosity have the greatest impact on contaminant migration distance, and the difference of sensitivity index between the two parameters is about 20%; (2) dispersity has the least impact on contaminant migration distance, and the sensitivity index of dispersity is one order of magnitude lower than that of permeability coefficient and porosity; and (3) contaminant migration distance shows a good linear correlation with permeability coefficient and porosity within 20% of variation ranges of both parameters.
In order to improve the precision of groundwater solute transport model and reduce the errors caused by the uncertainties of hydrogeological parameters, sensitivity analysis of parameters is needed for the numerical model. In this paper, a groundwater flow and solute transport model was established to simulate the pore water in an alluvial fan plain using GMS 7.0, and the model was verified. Sensitivity index was introduced to quantify parameter sensitivity. Factor transformation method, known as a local analysis method, was used to perform sensitivity analysis of permeability coefficient, porosity, and dispersity. Variation range of the parameters was set to be 20%. The results showed that (1) permeability coefficient and porosity have the greatest impact on contaminant migration distance, and the difference of sensitivity index between the two parameters is about 20%; (2) dispersity has the least impact on contaminant migration distance, and the sensitivity index of dispersity is one order of magnitude lower than that of permeability coefficient and porosity; and (3) contaminant migration distance shows a good linear correlation with permeability coefficient and porosity within 20% of variation ranges of both parameters.
2014, 12(3):138-142.
Abstract:
During the operation of hydroelectric projects in southwestern China, several large-scale landslide deposits, which are difficult to treat with, often reactivate due to reservoir a regulation. Controlling the range of water level fluctuation of the reservoir is the key point for the regular operation of hydroelectric project. In this paper, the control scheme of water level fluctuation in the Heishui River reservoir was proposed based on a reactivated landslide in the reservoir. First, the displacement variations of the landslide during the impoundment were analyzed using the monitored vertical displacement data at DM01 monitoring point of the landslide. Secondly, the main controlling factors for the landslide deformation were concluded. Finally, a prediction model for the displacement of landslide was developed using the stepwise regression method, which was used to predict the deformation of the landslide under the control scheme. The results showed that the control scheme can prevent the reactivation of the landslide.
During the operation of hydroelectric projects in southwestern China, several large-scale landslide deposits, which are difficult to treat with, often reactivate due to reservoir a regulation. Controlling the range of water level fluctuation of the reservoir is the key point for the regular operation of hydroelectric project. In this paper, the control scheme of water level fluctuation in the Heishui River reservoir was proposed based on a reactivated landslide in the reservoir. First, the displacement variations of the landslide during the impoundment were analyzed using the monitored vertical displacement data at DM01 monitoring point of the landslide. Secondly, the main controlling factors for the landslide deformation were concluded. Finally, a prediction model for the displacement of landslide was developed using the stepwise regression method, which was used to predict the deformation of the landslide under the control scheme. The results showed that the control scheme can prevent the reactivation of the landslide.
2014, 12(3):143-147.
Abstract:
In the overlapping uplift area of Daxing, the karst water is a significant component of groundwater resources in Beijing. In order to characterize the hydrogeological conditions of Nanyuan-Tongxian fault and Yongding River fault, a groundwater flow model was developed to simulate the covered karst system in the overlapping uplift area of Daxing using the groundwater numerical simulation software GMS. Both faults were simulated as the impervious boundary and permeable boundary in the model. The fitting effect between observed and simulated heads and water balance of the system were analyzed under the two conditions, which indicated that both faults are impervious fault. T he recharge of karst water aquifer is the leakage from overlying Quaternary porous aquifer. The research shows that numerical simulation method has advantages in the study of hydrogeological conditions of covered karst system.
In the overlapping uplift area of Daxing, the karst water is a significant component of groundwater resources in Beijing. In order to characterize the hydrogeological conditions of Nanyuan-Tongxian fault and Yongding River fault, a groundwater flow model was developed to simulate the covered karst system in the overlapping uplift area of Daxing using the groundwater numerical simulation software GMS. Both faults were simulated as the impervious boundary and permeable boundary in the model. The fitting effect between observed and simulated heads and water balance of the system were analyzed under the two conditions, which indicated that both faults are impervious fault. T he recharge of karst water aquifer is the leakage from overlying Quaternary porous aquifer. The research shows that numerical simulation method has advantages in the study of hydrogeological conditions of covered karst system.
2014, 12(3):148-151.
Abstract:
The connecting canal of south bank for Crossing the Yellow River Project is located in the loess area, which belongs to class I building with complicated geological conditions. About 2/3 of the canal section is located below groundwater level, and the highest height of high loess slope at this segment reaches 80 m. The high loess slope stability is one of key technical problems in construction of the South-to-North Water Diversion Project. In this paper, a large number of loess fundamental test data in the region were analyzed and the parameters were selected for the calculations of loess high slope stability of the outlet and inlet sections from the original design using the limit equilibrium method, nonlinear finite element analysis, and dynamic finite element analysis. A new slope design scheme was proposed based on the characteristics of loess. The results suggested that the new design is better according to the slops stability calculations.
The connecting canal of south bank for Crossing the Yellow River Project is located in the loess area, which belongs to class I building with complicated geological conditions. About 2/3 of the canal section is located below groundwater level, and the highest height of high loess slope at this segment reaches 80 m. The high loess slope stability is one of key technical problems in construction of the South-to-North Water Diversion Project. In this paper, a large number of loess fundamental test data in the region were analyzed and the parameters were selected for the calculations of loess high slope stability of the outlet and inlet sections from the original design using the limit equilibrium method, nonlinear finite element analysis, and dynamic finite element analysis. A new slope design scheme was proposed based on the characteristics of loess. The results suggested that the new design is better according to the slops stability calculations.
2014, 12(3):152-155.
Abstract:
Sesiman gully is the main tributary at the right bank of upstream of Daduhe River. Debris flow occurred in the gully, thus the security of hydropower station at the gully entrance is an important problem.. In this paper, on the basis of field investigations and comprehensive laboratory analysis, the formation conditions and risk assessment of debris flow in the Sesiman gully were discussed. The results showed that (1) the host rock of Sesiman gully is Yanshanian granite which has low weathering degree, but the glacial till is well developed and the main deposit fan at the gully entrance was formed in Last Glacial of Late Pleistocene; (2) the hydrologic conditions have varied significantly with the occurrence of low-frequency debris flow since Holocene; and (3) a huge dam-breaking debris flow can occur under the conditions of earthquake and extreme rainfall. The risk assessment results of debris flow in the Sesiman gully indicated that the gully has high risk of occurrence of debris flow.
Sesiman gully is the main tributary at the right bank of upstream of Daduhe River. Debris flow occurred in the gully, thus the security of hydropower station at the gully entrance is an important problem.. In this paper, on the basis of field investigations and comprehensive laboratory analysis, the formation conditions and risk assessment of debris flow in the Sesiman gully were discussed. The results showed that (1) the host rock of Sesiman gully is Yanshanian granite which has low weathering degree, but the glacial till is well developed and the main deposit fan at the gully entrance was formed in Last Glacial of Late Pleistocene; (2) the hydrologic conditions have varied significantly with the occurrence of low-frequency debris flow since Holocene; and (3) a huge dam-breaking debris flow can occur under the conditions of earthquake and extreme rainfall. The risk assessment results of debris flow in the Sesiman gully indicated that the gully has high risk of occurrence of debris flow.
2014, 12(3):156-159.
Abstract:
The suitability evaluation system of groundwater source heat pumps was constructed based on the hydrogeological and environmental conditions in Xi’an. The comprehensive weight of each evaluation index was determined using the combination method of subjective weighting method (analytic hierarchy process method) and objective weighting method (entropy method) based on the minimum information theory. On the basis of the determined scoring system, the comprehensive index method was used to determine the suitability zonation results of groundwater source heat pumps in Xi’an. The results indicated that the more suitable area for groundwater source heat pumps is about 171.228 km2, the less suitable area is 369.234 km2, the unsuitable area is 160.407 km2, and the construction forbidden area is 131.002 km2. The results can provide a scientific basis for planning and site selection of water source heat pumps in Xi’an.
The suitability evaluation system of groundwater source heat pumps was constructed based on the hydrogeological and environmental conditions in Xi’an. The comprehensive weight of each evaluation index was determined using the combination method of subjective weighting method (analytic hierarchy process method) and objective weighting method (entropy method) based on the minimum information theory. On the basis of the determined scoring system, the comprehensive index method was used to determine the suitability zonation results of groundwater source heat pumps in Xi’an. The results indicated that the more suitable area for groundwater source heat pumps is about 171.228 km2, the less suitable area is 369.234 km2, the unsuitable area is 160.407 km2, and the construction forbidden area is 131.002 km2. The results can provide a scientific basis for planning and site selection of water source heat pumps in Xi’an.
2014, 12(3):160-164.
Abstract:
In order to investigate the evolution of groundwater flow field in Huairou emergency well field, the variations of regional groundwater level and water level in the well field were analyzed from 1978 to 2010. The evolution of the flow field in the study area underwent four periods: natural flow field period before 1980, locally slow water level decline period from 1980 to 1985, dynamic balance period from 1986 to 1998, and significant water level decline period from 1999 to 2010. Further studies suggested that the natural factors, such as decreasing in precipitation and abandoned water, and human activities, such as change in the infiltration of underlying surface conditions and continuous groundwater pumping, have caused the reduction in groundwater recharge. In the past 30 years, the construction area of urban and rural settlements increased by approximately 120 km2, and the area of irrigated land and dry land decreased by nearly 102 km2, which resulted in the change in underlying surface conditions and thus significant reduction in precipitation infiltration. Continuous groundwater pumping caused 41-m drawdown of groundwater level in this area. The cone of depression expanded from locally to regionally with a depression area of 200 km2, indicating groundwater overexploitation status in the area. The capacity of single well and the total production of well field have decreased with continuous groundwater level decline and expansion of cone of depression. Therefore, water conservation engineering should be performed in the area, and the function of emergency and standby of water source site needs to be reinstated to ensure the safety of water supply. .
In order to investigate the evolution of groundwater flow field in Huairou emergency well field, the variations of regional groundwater level and water level in the well field were analyzed from 1978 to 2010. The evolution of the flow field in the study area underwent four periods: natural flow field period before 1980, locally slow water level decline period from 1980 to 1985, dynamic balance period from 1986 to 1998, and significant water level decline period from 1999 to 2010. Further studies suggested that the natural factors, such as decreasing in precipitation and abandoned water, and human activities, such as change in the infiltration of underlying surface conditions and continuous groundwater pumping, have caused the reduction in groundwater recharge. In the past 30 years, the construction area of urban and rural settlements increased by approximately 120 km2, and the area of irrigated land and dry land decreased by nearly 102 km2, which resulted in the change in underlying surface conditions and thus significant reduction in precipitation infiltration. Continuous groundwater pumping caused 41-m drawdown of groundwater level in this area. The cone of depression expanded from locally to regionally with a depression area of 200 km2, indicating groundwater overexploitation status in the area. The capacity of single well and the total production of well field have decreased with continuous groundwater level decline and expansion of cone of depression. Therefore, water conservation engineering should be performed in the area, and the function of emergency and standby of water source site needs to be reinstated to ensure the safety of water supply. .
2014, 12(3):165-169.
Abstract:
Due to long-term excessive groundwater exploitation, the North China Plain has become an area with the most excessive groundwater pumping, the largest area of groundwater depression cones and land subsidence, and the most complex subsidence type in the world. In this paper, GIS spatial analysis method was used to conduct comparative analysis of deep groundwater yield and land subsidence in the North China Plain and Cangzhou City. The results showed that the annual subsidence volume of the North China plain is 10.73×108 m3 until 2010 while the annual deep groundwater yield is about 24.5×108～26.75×108 m3. Therefore, the land subsidence volume accounted for 40.1% to 43.8% of deep groundwater yield in the North China Plain, indicating the proportion of released water from the compressibility of aquifer and the aquitard of the total deep groundwater yield. The annual subsidence volume was 1.98×108 m3 and the annual deep groundwater yield was about 3.44×108 m3 in Cangzhou region between 1970 and 2008. The proportion of subsidence volume of total deep groundwater yield was 57.6%, which was much higher than that of the North China Plain and can be explained by the lithological structure and recharge conditions of deep groundwater in Cangzhou region.
Due to long-term excessive groundwater exploitation, the North China Plain has become an area with the most excessive groundwater pumping, the largest area of groundwater depression cones and land subsidence, and the most complex subsidence type in the world. In this paper, GIS spatial analysis method was used to conduct comparative analysis of deep groundwater yield and land subsidence in the North China Plain and Cangzhou City. The results showed that the annual subsidence volume of the North China plain is 10.73×108 m3 until 2010 while the annual deep groundwater yield is about 24.5×108～26.75×108 m3. Therefore, the land subsidence volume accounted for 40.1% to 43.8% of deep groundwater yield in the North China Plain, indicating the proportion of released water from the compressibility of aquifer and the aquitard of the total deep groundwater yield. The annual subsidence volume was 1.98×108 m3 and the annual deep groundwater yield was about 3.44×108 m3 in Cangzhou region between 1970 and 2008. The proportion of subsidence volume of total deep groundwater yield was 57.6%, which was much higher than that of the North China Plain and can be explained by the lithological structure and recharge conditions of deep groundwater in Cangzhou region.
2014, 12(3):170-175.
Abstract:
Accurate knowledge of the spatial and temporal variations of flood disaster risk is of important significance for determining layout of urban disaster prevention. In this study, integrated flood risk index was used to evaluate the flood disaster risk in Harbin, and Markov Chain was used to analyze the spatial and temporal variations of flood disaster risk. The results showed that (1) the area with very high flood risk in Harbin has increased, the area with relative high and moderate flood risks has decreased, and the area with low flood risk has increased from 2000 to 2010;(2) the high level of flood disaster risk has increased gradually in the ten years, and the overall risk has increased but with different local variations; and (3) the interchange between middle risk level and high risk level is frequent, while the interchange between low risk level and lower risk level is relatively stable. Moreover, the interchange between high risk level and other risk levels are very active.
Accurate knowledge of the spatial and temporal variations of flood disaster risk is of important significance for determining layout of urban disaster prevention. In this study, integrated flood risk index was used to evaluate the flood disaster risk in Harbin, and Markov Chain was used to analyze the spatial and temporal variations of flood disaster risk. The results showed that (1) the area with very high flood risk in Harbin has increased, the area with relative high and moderate flood risks has decreased, and the area with low flood risk has increased from 2000 to 2010;(2) the high level of flood disaster risk has increased gradually in the ten years, and the overall risk has increased but with different local variations; and (3) the interchange between middle risk level and high risk level is frequent, while the interchange between low risk level and lower risk level is relatively stable. Moreover, the interchange between high risk level and other risk levels are very active.
2014, 12(3):176-179.
Abstract:
The one-dimensional unsteady flow model and weir gate hydrodynamic model were coupled to develop the one-dimensional river hydrodynamics model using the three-gradation method. The model was applied to simulate the historical flood in the Zhangwei River. The results showed that the model is applicable to solve the problems of the river crossing and overflow of weir gate, which can provide technical support for the flood operation in the Zhangwei River.
The one-dimensional unsteady flow model and weir gate hydrodynamic model were coupled to develop the one-dimensional river hydrodynamics model using the three-gradation method. The model was applied to simulate the historical flood in the Zhangwei River. The results showed that the model is applicable to solve the problems of the river crossing and overflow of weir gate, which can provide technical support for the flood operation in the Zhangwei River.
2014, 12(3):180-185.
Abstract:
In order to save water resources and improve the level of agricultural irrigation management, an agricultural irrigation intelligent decision-making tool, including agricultural irrigation planning sub-system and real-time irrigation sub-system, was developed based on the SWAT model and agricultural water balance theory. The function requirement and realization of each system were introduced from the perspective of overall design of the tool. The developed tool was applied in Guantao County. The application results showed that the simulated evapotranspiration from the agricultural irrigation planning sub-system is similar to the measured value, so this system can be used to optimize agricultural management practice. The real-time irrigation sub-system can predict the soil moisture and determine the irrigation time and amount. The tool can provide technical support for the efficient use of water resources and automation management in agricultural irrigation on county scale.
In order to save water resources and improve the level of agricultural irrigation management, an agricultural irrigation intelligent decision-making tool, including agricultural irrigation planning sub-system and real-time irrigation sub-system, was developed based on the SWAT model and agricultural water balance theory. The function requirement and realization of each system were introduced from the perspective of overall design of the tool. The developed tool was applied in Guantao County. The application results showed that the simulated evapotranspiration from the agricultural irrigation planning sub-system is similar to the measured value, so this system can be used to optimize agricultural management practice. The real-time irrigation sub-system can predict the soil moisture and determine the irrigation time and amount. The tool can provide technical support for the efficient use of water resources and automation management in agricultural irrigation on county scale.
2014, 12(3):186-190.
Abstract:
The annual variation trend and variation stability degree of runoff in the downstream of Zhanghe River were analyzed using the Mann-Kendall trend method and coefficient of variation method based on the collected data from 1962 to 2006, which provided the evolution of river flow in the downstream of Zhanghe River. On the basis, a multi-objective ecological regulation model of reservoirs was developed according to the objectives of flood control, water conservancy, and ecological environment. The model was used to perform ecological regulation on the Yuecheng reservoir in the downstream of Zhanghe River using the particle swarm optimization method. The results showed that the model can realize the multi-objective regulation in consideration of the flood control, water supply, and ecological requirements. The regulation results suggested that the runoff in the downstream of Zhanghe River has a significant decreasing trend with a large annual variation, and the Yuecheng reservoir can deeply affect the hydrological conditions in the downstream of Zhanghe River. During the flood season of wet year, Zhanghe River discharge can meet the water demand, while the water scarcity situation was serious in the normal and dry years. In the other time periods except for flood season, water release from reservoir regulation was needed to avoid the occurrence of drying in the river.
The annual variation trend and variation stability degree of runoff in the downstream of Zhanghe River were analyzed using the Mann-Kendall trend method and coefficient of variation method based on the collected data from 1962 to 2006, which provided the evolution of river flow in the downstream of Zhanghe River. On the basis, a multi-objective ecological regulation model of reservoirs was developed according to the objectives of flood control, water conservancy, and ecological environment. The model was used to perform ecological regulation on the Yuecheng reservoir in the downstream of Zhanghe River using the particle swarm optimization method. The results showed that the model can realize the multi-objective regulation in consideration of the flood control, water supply, and ecological requirements. The regulation results suggested that the runoff in the downstream of Zhanghe River has a significant decreasing trend with a large annual variation, and the Yuecheng reservoir can deeply affect the hydrological conditions in the downstream of Zhanghe River. During the flood season of wet year, Zhanghe River discharge can meet the water demand, while the water scarcity situation was serious in the normal and dry years. In the other time periods except for flood season, water release from reservoir regulation was needed to avoid the occurrence of drying in the river.
2014, 12(3):191-194.
Abstract:
The testing results of thermal conductivity of the extruded polystyrene (XPS) insulating board during the construction of Jiaozuo 1st engineering project in the Middle Route of South-to-North Water Diversion Project did not meet the technical requirements. In order to determine the effects of thermal conductivity of the XPS insulating board on channel anti-frost-heavy and to coordinate the relationships between project entity, design, management, and construction, the thickness of XPS insulating board was inversely calculated based on the analysis of test report, method, and instrument and the related national and industrial standards. The results showed the r thermal conductivity values of XPS insulating board in the channel anti-frost-heavy practice range from 0.067 to 0.090 W/(m?k). According to the actual thickness of insulating board and the anti-frost-heavy practice, the suggested thermal conductivity values of XPS insulating board were 0.039 W/(m?k) when the mean temperature was below 25℃ and0.028 W/(m?k) when the mean temperature was below 10℃. The scientific assignment to thermal conductivity is the key to ensure the project quality.
The testing results of thermal conductivity of the extruded polystyrene (XPS) insulating board during the construction of Jiaozuo 1st engineering project in the Middle Route of South-to-North Water Diversion Project did not meet the technical requirements. In order to determine the effects of thermal conductivity of the XPS insulating board on channel anti-frost-heavy and to coordinate the relationships between project entity, design, management, and construction, the thickness of XPS insulating board was inversely calculated based on the analysis of test report, method, and instrument and the related national and industrial standards. The results showed the r thermal conductivity values of XPS insulating board in the channel anti-frost-heavy practice range from 0.067 to 0.090 W/(m?k). According to the actual thickness of insulating board and the anti-frost-heavy practice, the suggested thermal conductivity values of XPS insulating board were 0.039 W/(m?k) when the mean temperature was below 25℃ and0.028 W/(m?k) when the mean temperature was below 10℃. The scientific assignment to thermal conductivity is the key to ensure the project quality.
2014, 12(3):195-197.
Abstract:
The incipient motion of sediment is one of the most important subjects for the research of river dynamics. In this paper, the probability formula of incipient motion of non-uniform sediment was deduced using the combination method of probability and mechanics in consideration of the impacts of exposure degree and shape of sediment on the threshold velocity. The relationship between threshold velocity and threshold probability was developed. Compared with the measured incipient velocity, the formula can reflect the movement of non-uniform sediment accurately.
The incipient motion of sediment is one of the most important subjects for the research of river dynamics. In this paper, the probability formula of incipient motion of non-uniform sediment was deduced using the combination method of probability and mechanics in consideration of the impacts of exposure degree and shape of sediment on the threshold velocity. The relationship between threshold velocity and threshold probability was developed. Compared with the measured incipient velocity, the formula can reflect the movement of non-uniform sediment accurately.
2014, 12(3):198-200.
Abstract:
In the Middle Route of South-to-North Water Transfer Project in Ci county of Hebei, most of the widespread clay rock of the Neogene system Miocene series stratum shows swelling characteristics. Strong, medium, weak, and non-swelling rock (soil) is in interlaced distribution, which can be compared with the swelling rock (soil) in other areas. Based on the identification of field and laboratory data, the relationship between each index of the swelling rock (soil) was analyzed. The rapid field identification method of the grade of swelling rock (soil) was obtained from the engineering geological characteristics such as color, structure, and fracture development. The research result is of important significance to the selection of engineering method, excavation, and field geology.
In the Middle Route of South-to-North Water Transfer Project in Ci county of Hebei, most of the widespread clay rock of the Neogene system Miocene series stratum shows swelling characteristics. Strong, medium, weak, and non-swelling rock (soil) is in interlaced distribution, which can be compared with the swelling rock (soil) in other areas. Based on the identification of field and laboratory data, the relationship between each index of the swelling rock (soil) was analyzed. The rapid field identification method of the grade of swelling rock (soil) was obtained from the engineering geological characteristics such as color, structure, and fracture development. The research result is of important significance to the selection of engineering method, excavation, and field geology.
44 Study on Water-saving Mode Test in Border Irrigation Technology of Hebei Typical Irrigation District
2014, 12(3):201-204.
Abstract:
Border irrigation is one of the most popular surface irrigation methods. The border irrigation technology in the experimental district is promoted and it found the suitable water-saving border irrigation program, which can improve the water use efficiency and relief the water shortage. Comparative test are taken for winter wheat in different irrigation program in Shijin Irrigation District, including water use efficiency and crop yield. It studied the influence of the side of border with the width of 10 m and 3m in combined well with canals area. The result shows that the optimum irrigation quotas are 2 250 m3/hm2 and 2 700 m3/hm2 respectively to ensure the yield above 6 750 kg/hm2 in the condition of normal soil fertility, medium drought year and sufficient seeding. The optimum border size should be 30～50 m long and 3m wide.
Border irrigation is one of the most popular surface irrigation methods. The border irrigation technology in the experimental district is promoted and it found the suitable water-saving border irrigation program, which can improve the water use efficiency and relief the water shortage. Comparative test are taken for winter wheat in different irrigation program in Shijin Irrigation District, including water use efficiency and crop yield. It studied the influence of the side of border with the width of 10 m and 3m in combined well with canals area. The result shows that the optimum irrigation quotas are 2 250 m3/hm2 and 2 700 m3/hm2 respectively to ensure the yield above 6 750 kg/hm2 in the condition of normal soil fertility, medium drought year and sufficient seeding. The optimum border size should be 30～50 m long and 3m wide.
2014, 12(3):205-208.
Abstract:
When the water level is high in the Danjiangkou Reservoir, the following problems occur in its accessory dam – the pivotal project of Taocha Canal Headwork, such as seepage in the dam base and around the dam, therefore the seepage control treatment needs to be conducted to the dam base and dam foundation. Based on the field curtain grouting experiment and the project characteristics, a reasonable seepage control treatment design and construction scheme for dam base was proposed, which can solve the following problems including drilling holes in deep overburden layers, burying and covering up grout nipple, grouting at the contact face between the land and rock, and curtain grouting to the highly permeable karst rock mass under the deep overburden layers. After the completion of the seepage control treatment for dam base, the quality and safety of the project were investigated, and the results showed that the seepage control treatment for dam base in the pivotal project of Taocha Canal Headwork meets the design requirements and achieves the desired results. The field curtain grouting experiment method, and design and construction scheme can provide reference for solving similar problems of seepage control of deep overburden layers.
When the water level is high in the Danjiangkou Reservoir, the following problems occur in its accessory dam – the pivotal project of Taocha Canal Headwork, such as seepage in the dam base and around the dam, therefore the seepage control treatment needs to be conducted to the dam base and dam foundation. Based on the field curtain grouting experiment and the project characteristics, a reasonable seepage control treatment design and construction scheme for dam base was proposed, which can solve the following problems including drilling holes in deep overburden layers, burying and covering up grout nipple, grouting at the contact face between the land and rock, and curtain grouting to the highly permeable karst rock mass under the deep overburden layers. After the completion of the seepage control treatment for dam base, the quality and safety of the project were investigated, and the results showed that the seepage control treatment for dam base in the pivotal project of Taocha Canal Headwork meets the design requirements and achieves the desired results. The field curtain grouting experiment method, and design and construction scheme can provide reference for solving similar problems of seepage control of deep overburden layers.
2014, 12(3):209-213.
Abstract:
The hydraulic characteristic of high-speed flow is a key issue in selection of discharge structures. The deep discharge tunnel of a hydropower station was reconstructed from an existing diversion tunnel. In the design process, two schemes were considered: the vortex shaft discharge tunnel and the ogee discharge tunnel. Through the comparison and analysis of hydraulic model tests, the ogee discharge tunnel showed many advantages, including simple structures, investment saving, stable flow, and high discharge capacity. The cavitation erosion problems caused by the high-speed water flow can be solved using the measures of shape optimization and aeration facilities. After the comprehensive comparison of the two schemes, the ogee discharge tunnel was adopted.
The hydraulic characteristic of high-speed flow is a key issue in selection of discharge structures. The deep discharge tunnel of a hydropower station was reconstructed from an existing diversion tunnel. In the design process, two schemes were considered: the vortex shaft discharge tunnel and the ogee discharge tunnel. Through the comparison and analysis of hydraulic model tests, the ogee discharge tunnel showed many advantages, including simple structures, investment saving, stable flow, and high discharge capacity. The cavitation erosion problems caused by the high-speed water flow can be solved using the measures of shape optimization and aeration facilities. After the comprehensive comparison of the two schemes, the ogee discharge tunnel was adopted.
2014, 12(3):214-216.
Abstract:
The selection of hazardous waste disposal site is a complicated system engineering problem, and its influencing factors have the characteristics such as information incompleteness, uncertainty, and fuzziness. In this paper, a multi-level and multi-objective evaluation index system was developed in Chengdu City in consideration of geological structure, geographical factors, stratigraphic lithology, hydrogeological conditions, surface drainage, and geological disaster distribution. The fuzzy mathematical comprehensive evaluation method was used to analyze the selection of hazardous waste disposal site in Chengdu City. The results suggested that the fuzzy mathematical improved model is scientific and practical, easy to operate, and has certain practical application value, thus it can provide reference for related projects.
The selection of hazardous waste disposal site is a complicated system engineering problem, and its influencing factors have the characteristics such as information incompleteness, uncertainty, and fuzziness. In this paper, a multi-level and multi-objective evaluation index system was developed in Chengdu City in consideration of geological structure, geographical factors, stratigraphic lithology, hydrogeological conditions, surface drainage, and geological disaster distribution. The fuzzy mathematical comprehensive evaluation method was used to analyze the selection of hazardous waste disposal site in Chengdu City. The results suggested that the fuzzy mathematical improved model is scientific and practical, easy to operate, and has certain practical application value, thus it can provide reference for related projects.
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