Volume 18,Issue 3,2020 Table of Contents
2020, 18(3):1-14.
Abstract:
Hydrological scale effect has always been the frontier research in hydrology. ln this paper,a quantitative conversion e quation between different spatial scales of a model's sensitive parameters is established based on the fractal theory ,and a method for analyzing the spatial scale effects of hydrological model parameters is proposed. Taking the three-source Xin' anjiang model as an example, the spatial scale effect of model parameters is analyzed above the Xiaoheha station of Jialing River Basin. The results showed that the results sensitive parameters (SM, KG, KI, CG，CI，and CS) of the Xin' anjiang model are scale-invariant with the change of spatial scale, and the quantitative relationship between them and catchment area can be described by power function relationship. Therefore, the corresponding quantilative conversion equation can be eslahlished by this relationship. Through the application and validation on different spatial scales in the basin, it is found that this spatial scale conversion equa tion of the Xin' anjiang model based on the scale-invariance using fractal theory has high applicability. It can realize that the migration of model parameters can be done from the data-rich region to the no data region and can provide references for the deter-mination of model parameters in no data regions.
Hydrological scale effect has always been the frontier research in hydrology. ln this paper,a quantitative conversion e quation between different spatial scales of a model's sensitive parameters is established based on the fractal theory ,and a method for analyzing the spatial scale effects of hydrological model parameters is proposed. Taking the three-source Xin' anjiang model as an example, the spatial scale effect of model parameters is analyzed above the Xiaoheha station of Jialing River Basin. The results showed that the results sensitive parameters (SM, KG, KI, CG，CI，and CS) of the Xin' anjiang model are scale-invariant with the change of spatial scale, and the quantitative relationship between them and catchment area can be described by power function relationship. Therefore, the corresponding quantilative conversion equation can be eslahlished by this relationship. Through the application and validation on different spatial scales in the basin, it is found that this spatial scale conversion equa tion of the Xin' anjiang model based on the scale-invariance using fractal theory has high applicability. It can realize that the migration of model parameters can be done from the data-rich region to the no data region and can provide references for the deter-mination of model parameters in no data regions.
2020, 18(3):15-30.
Abstract:
In the past 50 years, evidence showed that climate change and human activities have affected the hydrological processes in the Luan River Basin. In order to identify the main causes for runoff changes, the upper reaches of the Luan River Basin are taken as the research area, and the Mann-Kendall test method is used to analyze the trend of meteorological and hydrological factors from 1966 to 2015 in the study area. Simultaneously,the hydrothermal coupling equilibrium equation based on the Budy ko hypothesis is established. The elastic coefficient method is used to calculate the sensitivity coefficient of the influencing factors to runoff change. Furthem1ore, a quantitative contribution assessment of each factor to runoff change is also carried out in the study area The results show that the annual runoff decreased significantly from 1966 to 2015, and there is no significant change in annual precipitation and annual evapotranspiration in the upper reaches of the Luan River Basin. Compared with the base period (1966-1979), the change of the underlying surface is the main influencing factor of runoff reduction. The contribution rate of underlying surface change to runoff change in 198C-1997 (phase I) and 1998 2015 (phase II) is 52. 68% and 88.12%, respectively. Among the climatic factors, the impact of precipitation on runoff changes is more significant compare to potential evapotranspiration.
In the past 50 years, evidence showed that climate change and human activities have affected the hydrological processes in the Luan River Basin. In order to identify the main causes for runoff changes, the upper reaches of the Luan River Basin are taken as the research area, and the Mann-Kendall test method is used to analyze the trend of meteorological and hydrological factors from 1966 to 2015 in the study area. Simultaneously,the hydrothermal coupling equilibrium equation based on the Budy ko hypothesis is established. The elastic coefficient method is used to calculate the sensitivity coefficient of the influencing factors to runoff change. Furthem1ore, a quantitative contribution assessment of each factor to runoff change is also carried out in the study area The results show that the annual runoff decreased significantly from 1966 to 2015, and there is no significant change in annual precipitation and annual evapotranspiration in the upper reaches of the Luan River Basin. Compared with the base period (1966-1979), the change of the underlying surface is the main influencing factor of runoff reduction. The contribution rate of underlying surface change to runoff change in 198C-1997 (phase I) and 1998 2015 (phase II) is 52. 68% and 88.12%, respectively. Among the climatic factors, the impact of precipitation on runoff changes is more significant compare to potential evapotranspiration.
2020, 18(3):31-47.
Abstract:
Soil moisture content is an important factor affecting soil evaporation Analyzing the influence of soil moisture variation on soil evaporation has a positive effect on water resource management. The remote sensing Penman-Monteith (P-M) model is a remote sensing based method for evapotranspiration simulation and can calculate soil evaporation and vegetation transpiration separately. This study calculates the evapotranspiration for Wangdu station and investigates the effects of soil moisture on the model parameters and soil evaporation. The results showed that the model has a good performance at Wangdu station with a value of NSE (0. 559). There is an uncertain relationship between soil moisture and model parameters. Comparing with the vegetation transpiration, the consistency of soil moisture and soil evaporation is stronger in the simulation period for this particular research.
Soil moisture content is an important factor affecting soil evaporation Analyzing the influence of soil moisture variation on soil evaporation has a positive effect on water resource management. The remote sensing Penman-Monteith (P-M) model is a remote sensing based method for evapotranspiration simulation and can calculate soil evaporation and vegetation transpiration separately. This study calculates the evapotranspiration for Wangdu station and investigates the effects of soil moisture on the model parameters and soil evaporation. The results showed that the model has a good performance at Wangdu station with a value of NSE (0. 559). There is an uncertain relationship between soil moisture and model parameters. Comparing with the vegetation transpiration, the consistency of soil moisture and soil evaporation is stronger in the simulation period for this particular research.
2020, 18(3):48-56.
Abstract:
In order to explore the influence of different evaporation data on the accuracy and quality of rainfall runoff simulations, Pan evaporation, potential evapotranspiration estimated by discretized Thornthwaite empirical formula and the fixed value as e vaporation data were selected as inputs to simulate the runoff process using Xin'anjiang model from 1981 to 2004 in the Tunxi watershed. The effect of three kinds of data on runoff simulation results were compared and analyzed. Funhermore, the sensitivity of different seasons on the accuracy of evaporation data was analyzed based on the error regularity of each season in a year. The results showed that the average deterministic coefficient of pan evaporation, and evapotranspiration estimated hy formula and fixed values were 0.90,0.89 and 0.86，respectively,while the applicability of evapotranspiration estimated by formula was better. On the seasonal scale, spring and autumn seasonal changes were more sensitive to seasonal evaporatior data and tequiredhigher accuracy of potential evapotranspiration in the basin. By optimizing the simulation results using fixed value of evaporation in winter showed that the scheme of fixed value had good applicability in summer and winter instead of the evaporation capacity of the basin. The evaporation in winter was fixed to 1mm showed good simulation results.
In order to explore the influence of different evaporation data on the accuracy and quality of rainfall runoff simulations, Pan evaporation, potential evapotranspiration estimated by discretized Thornthwaite empirical formula and the fixed value as e vaporation data were selected as inputs to simulate the runoff process using Xin'anjiang model from 1981 to 2004 in the Tunxi watershed. The effect of three kinds of data on runoff simulation results were compared and analyzed. Funhermore, the sensitivity of different seasons on the accuracy of evaporation data was analyzed based on the error regularity of each season in a year. The results showed that the average deterministic coefficient of pan evaporation, and evapotranspiration estimated hy formula and fixed values were 0.90,0.89 and 0.86，respectively,while the applicability of evapotranspiration estimated by formula was better. On the seasonal scale, spring and autumn seasonal changes were more sensitive to seasonal evaporatior data and tequiredhigher accuracy of potential evapotranspiration in the basin. By optimizing the simulation results using fixed value of evaporation in winter showed that the scheme of fixed value had good applicability in summer and winter instead of the evaporation capacity of the basin. The evaporation in winter was fixed to 1mm showed good simulation results.
2020, 18(3):57-64.
Abstract:
To reasonably evaluate the water resource state in Hubei Province, based on the systematical consideration of characteristics and actual situation of water resources in Hubei Province, following the principles of representative, scientific, operational and systematic index system construction, we have built the water resource evaluation index system of the Hubei Province on the basis of the Driving Force-Pressure-State-lmpact-Response (DPSIR) concept framework, established a water resource evaluation model by combining the entropy weight method with the fuzzy set pair analysis melhod and conducted quantitative evaluations of the water resource states from 2008 tO 2016. The results have show: (1) The waler resource status in Hubei Province shows a trend of fluctuating increase from 2008 to 2016, which shows that the water resources in Hubei Province is in good condition: (2) From the DPSIR evaluation results of water resources, we can see that the impact of water resources and the response of water resources are the most important factors affecting water resources condition in Hubei Province.
To reasonably evaluate the water resource state in Hubei Province, based on the systematical consideration of characteristics and actual situation of water resources in Hubei Province, following the principles of representative, scientific, operational and systematic index system construction, we have built the water resource evaluation index system of the Hubei Province on the basis of the Driving Force-Pressure-State-lmpact-Response (DPSIR) concept framework, established a water resource evaluation model by combining the entropy weight method with the fuzzy set pair analysis melhod and conducted quantitative evaluations of the water resource states from 2008 tO 2016. The results have show: (1) The waler resource status in Hubei Province shows a trend of fluctuating increase from 2008 to 2016, which shows that the water resources in Hubei Province is in good condition: (2) From the DPSIR evaluation results of water resources, we can see that the impact of water resources and the response of water resources are the most important factors affecting water resources condition in Hubei Province.
2020, 18(3):65-72.
Abstract:
ln this study,eight monitoring stations were selected to analyze the spatial and temporal characteristics of water cycle elements, such as precipitation,runoff,and evaporation in the basin. For this purpose,measured hydrological data from 1952 to 2015, the Mann-Kendall nonparametric test and Morlet wavelet transform were used. The results indicated that precipitation showed an increasing trend, and the runoff and evaporation showed a decreasing trend in the basin. The interannual variation cycle of each water cycle element had multiple time scales nested with each other. The main cycle of precipitation and evaporation was 25a, and runoff was 3la,respectively. The distribution of water cycle elements was uneven during the year, while the precipitation was concentrated in June-August. The peak value of runoff was one month behind the precipitation, and the maximum value of evaporation appeared in June. The spatial distribution was uneven, which characterized by the decreasing trend of precipitation from southeast to northwest. The spatial distribution pattern of runoff depth was consistent with precipitation. The change of water cycle elements in Hudong area was greater than that in Huxi area. The temporal and spatial variation characteristics of the water cycle elements of the basin may be affected by climate change and human activities.
ln this study,eight monitoring stations were selected to analyze the spatial and temporal characteristics of water cycle elements, such as precipitation,runoff,and evaporation in the basin. For this purpose,measured hydrological data from 1952 to 2015, the Mann-Kendall nonparametric test and Morlet wavelet transform were used. The results indicated that precipitation showed an increasing trend, and the runoff and evaporation showed a decreasing trend in the basin. The interannual variation cycle of each water cycle element had multiple time scales nested with each other. The main cycle of precipitation and evaporation was 25a, and runoff was 3la,respectively. The distribution of water cycle elements was uneven during the year, while the precipitation was concentrated in June-August. The peak value of runoff was one month behind the precipitation, and the maximum value of evaporation appeared in June. The spatial distribution was uneven, which characterized by the decreasing trend of precipitation from southeast to northwest. The spatial distribution pattern of runoff depth was consistent with precipitation. The change of water cycle elements in Hudong area was greater than that in Huxi area. The temporal and spatial variation characteristics of the water cycle elements of the basin may be affected by climate change and human activities.
2020, 18(3):73-80.
Abstract:
The study on the natural runoff characteristics of Yalong River Basin has important significance for the operation and management of cascade hydropower stations and the planning of hydropower development and utilization in the future. This paper selected three typical years of extremely high，above-average and extremely low annual runoff. The water balance method was used to restore the natural numff of the river. The Gini coefficient and the runoff contribution rate were used to analvze the temporal and spatial distribution characteristics of natural runoff. The results showed that Gini coefficients of each station were between 0.30 and 0.3 9, respectively, and the distribution of natural runoff was relatively unifom1 in extremely dry years. Gini coefficient of each station was between 0. 40 and 0.59，and the distribution of natural runoff was relatively uneven in above-aver age and extremely high annual runoff years. Gini coefficient of special abundance, partial abundance and special dry years were 0.49,0.43 and 0.35，respectively, and the distribution inhomogeneity of natural runoff was positively correlated with lotal runoff. In the dry season, the proportion of contribution rate of runoff in the upper, middle and lower reaches of the basin was close to 1 : l : l in extremely low and above-average annual runoff years, while the runoff contribution rate was followed by upstream,dowmstream and midstream in the Year of extremely high annual runoff. The spatial distribution characteristics of runoff in the flood season and the whole year were the same. The runoff contribution rate of the basin was followed upstream, down stream and midstream in the years of extremely high and extremely low annual runoff, while the proportion of the runoff contribution rate of the basin was close to 1 : 1 : 1 in the Year of above-average annual runoff. Overall, the spatial distribution pattern of left bank runoff was larger than the right bank runoff. The distribution of natural runoff time in the Yalong River Basin was mainly affected by rainfall factors, while the spatial distribution characteristics were detemiined by various factors such as rain fall, topography and catchment area.
The study on the natural runoff characteristics of Yalong River Basin has important significance for the operation and management of cascade hydropower stations and the planning of hydropower development and utilization in the future. This paper selected three typical years of extremely high，above-average and extremely low annual runoff. The water balance method was used to restore the natural numff of the river. The Gini coefficient and the runoff contribution rate were used to analvze the temporal and spatial distribution characteristics of natural runoff. The results showed that Gini coefficients of each station were between 0.30 and 0.3 9, respectively, and the distribution of natural runoff was relatively unifom1 in extremely dry years. Gini coefficient of each station was between 0. 40 and 0.59，and the distribution of natural runoff was relatively uneven in above-aver age and extremely high annual runoff years. Gini coefficient of special abundance, partial abundance and special dry years were 0.49,0.43 and 0.35，respectively, and the distribution inhomogeneity of natural runoff was positively correlated with lotal runoff. In the dry season, the proportion of contribution rate of runoff in the upper, middle and lower reaches of the basin was close to 1 : l : l in extremely low and above-average annual runoff years, while the runoff contribution rate was followed by upstream,dowmstream and midstream in the Year of extremely high annual runoff. The spatial distribution characteristics of runoff in the flood season and the whole year were the same. The runoff contribution rate of the basin was followed upstream, down stream and midstream in the years of extremely high and extremely low annual runoff, while the proportion of the runoff contribution rate of the basin was close to 1 : 1 : 1 in the Year of above-average annual runoff. Overall, the spatial distribution pattern of left bank runoff was larger than the right bank runoff. The distribution of natural runoff time in the Yalong River Basin was mainly affected by rainfall factors, while the spatial distribution characteristics were detemiined by various factors such as rain fall, topography and catchment area.
2020, 18(3):81-90.
Abstract:
Scientific planning of roads and other linear features is an important means of coordinating the contradiction between flood control and detention areasand economic development. Therefore, in this paper, the flood danger, exposure, and vulnerability, the scientific planning of roads and other linear ground features were discussed based the on flood risk management model in the Dahuangpuwa flood detention area in Tianjin . Moreover, the way to determine the optimal road construction plan from flood risk was put forward. Given the irregularity of the spatial distribution of various kinds of property in the flood detention area， which leads to the characteristics of random variation of flood losses with geomorphology, flooding results calculated by hydrodynamic models need to be used to determine flood risk. The application in Dahuangpuwa flood detention area in Tianjin showed that road planning based on flood risk was necessary,and it has the advantage of taking into account the overall flood control. 1n conclusion, the arrangements of the road in Dahuangpuwa flood detention area, the direction of the road should be 90°with the mainstream direction of flood routing.while the road position should be about 10 km from the flood diversion gate and the size of the culvert should be 3m. By doing this practice the economic loss caused by the flood may be the least, and the flood risk under this scheme may mininial.
Scientific planning of roads and other linear features is an important means of coordinating the contradiction between flood control and detention areasand economic development. Therefore, in this paper, the flood danger, exposure, and vulnerability, the scientific planning of roads and other linear ground features were discussed based the on flood risk management model in the Dahuangpuwa flood detention area in Tianjin . Moreover, the way to determine the optimal road construction plan from flood risk was put forward. Given the irregularity of the spatial distribution of various kinds of property in the flood detention area， which leads to the characteristics of random variation of flood losses with geomorphology, flooding results calculated by hydrodynamic models need to be used to determine flood risk. The application in Dahuangpuwa flood detention area in Tianjin showed that road planning based on flood risk was necessary,and it has the advantage of taking into account the overall flood control. 1n conclusion, the arrangements of the road in Dahuangpuwa flood detention area, the direction of the road should be 90°with the mainstream direction of flood routing.while the road position should be about 10 km from the flood diversion gate and the size of the culvert should be 3m. By doing this practice the economic loss caused by the flood may be the least, and the flood risk under this scheme may mininial.
2020, 18(3):91-109.
Abstract:
The Hekouzhen-Longmen region of the middle reaches in the Yellow River is a key and typical area for the implementation of the Grain for Green Project (GGP) in China. It is of great significance for the sustainable utilization of water resources and the eco-hydrological effect assessment of the GGP project to quantitatively evaluate the vegetation dynamics and its impact on runoff in the basin. Based on remote sensing, GIS technology, mathematical statistics, and Budyko framework, the spatial-temporal change pattern of vegetation cover and its impact on runoff change is quantitatively evaluated using different vegetation type data of seven periods in the Hekouzhen-Longmen region for past 37 years. The results indicate that; 1) the change in vegetation do not significantly change the temporal and spatial distribution pattern of each vegetation type in the Hekouzhen-Longmen region;2) the implementation of the GGP change the equilibrium status and transformation rate of each vegetation type;3) vegetation changes are the main driving factor of runoff decline after the implementation of GGP in the last 10 years ( 2000-20l0), but the subsequent continuous increase in precipitation make the ”water reduction effect” of vegetation tend to ease.
The Hekouzhen-Longmen region of the middle reaches in the Yellow River is a key and typical area for the implementation of the Grain for Green Project (GGP) in China. It is of great significance for the sustainable utilization of water resources and the eco-hydrological effect assessment of the GGP project to quantitatively evaluate the vegetation dynamics and its impact on runoff in the basin. Based on remote sensing, GIS technology, mathematical statistics, and Budyko framework, the spatial-temporal change pattern of vegetation cover and its impact on runoff change is quantitatively evaluated using different vegetation type data of seven periods in the Hekouzhen-Longmen region for past 37 years. The results indicate that; 1) the change in vegetation do not significantly change the temporal and spatial distribution pattern of each vegetation type in the Hekouzhen-Longmen region;2) the implementation of the GGP change the equilibrium status and transformation rate of each vegetation type;3) vegetation changes are the main driving factor of runoff decline after the implementation of GGP in the last 10 years ( 2000-20l0), but the subsequent continuous increase in precipitation make the ”water reduction effect” of vegetation tend to ease.
MENG Qingbo
,
,
LIU Yanli
,
JU Qin
,
LlU Ji
,
GUAN Tiesheng
,
WANG Guoqing
,
JIN Junliang
,
HE Ruinmin
,
LlU Cuishan
,
BAO Zhenxin
,
2020, 18(3):110-118.
Abstract:
There are few meteorologicol stations located in the plateau and cold mountain orea of the Niyang River Basin,China. It is a typical area that has a data shortage. Therefore, satellite precipitation data is an important supplement. Due to the indirectness of the acquisition of satellite precipitation data and its uncertainty,data accuracy has always been a major barrier to its effective application. Based on the Ensemble Kalman Filter (EnKF) assimilation algorithm, five satellite precipitation products including TRMM,CHIRPS,Cmorph_Vl.O,PERSLANN－CDR and Gldas_Noah were selected.The multi-source precipitation data assimilation and fusion were carried out because of the accuracy analysis of the measured precipitation in the grid area of Linzhi Station. The results showed that the correlation coefficients of the five satellite precipitation data products with original satellite precipitation increased up to 0. 98 after assimilation, the BIAS was below 10%, ME was less than 0.2 mm/day,and the RMSE was less than 0.6 mm/day,respectively,The effect of EnKF’s assimilation was significant. The error sequence between the assimilated five kinds of precipitation and the original satellite precipitation was extended to the whole basin so that the five assimilated precipitations in the whole hasin were used for fusion. The combined precipitation data integrated the advantages of the five precipitation data products in the accuracy index, while its accuracy and reliability were much higher. Kriging interpolation method was used to analyze the tempornl and spatial distribution characteristics of precipitation after integration in Niyang River Basin. The results showed that the spatial distribution of annual precipitation decreased gradually from the midland to the surrounding, and showed an increasing trend year by year. Through assimilation and integration of satellite precipitation data, it may provide a time series of precipitation for the requirements of hydrological simulation and water resources management, which has important application value.
There are few meteorologicol stations located in the plateau and cold mountain orea of the Niyang River Basin,China. It is a typical area that has a data shortage. Therefore, satellite precipitation data is an important supplement. Due to the indirectness of the acquisition of satellite precipitation data and its uncertainty,data accuracy has always been a major barrier to its effective application. Based on the Ensemble Kalman Filter (EnKF) assimilation algorithm, five satellite precipitation products including TRMM,CHIRPS,Cmorph_Vl.O,PERSLANN－CDR and Gldas_Noah were selected.The multi-source precipitation data assimilation and fusion were carried out because of the accuracy analysis of the measured precipitation in the grid area of Linzhi Station. The results showed that the correlation coefficients of the five satellite precipitation data products with original satellite precipitation increased up to 0. 98 after assimilation, the BIAS was below 10%, ME was less than 0.2 mm/day,and the RMSE was less than 0.6 mm/day,respectively,The effect of EnKF’s assimilation was significant. The error sequence between the assimilated five kinds of precipitation and the original satellite precipitation was extended to the whole basin so that the five assimilated precipitations in the whole hasin were used for fusion. The combined precipitation data integrated the advantages of the five precipitation data products in the accuracy index, while its accuracy and reliability were much higher. Kriging interpolation method was used to analyze the tempornl and spatial distribution characteristics of precipitation after integration in Niyang River Basin. The results showed that the spatial distribution of annual precipitation decreased gradually from the midland to the surrounding, and showed an increasing trend year by year. Through assimilation and integration of satellite precipitation data, it may provide a time series of precipitation for the requirements of hydrological simulation and water resources management, which has important application value.
2020, 18(3):119-126.
Abstract:
With the advancement of the prevention of flashflood disasters in the small watershed of the mountainous area，the local key areas ( villages and towns) along the river in hilly areas have become the focus of flash flood disasters. It is critical anddifficult to analyze and to calculate the risk of each village along the river, to determine the unified disaster water level, and to analyze the submersed number of people under different frequencies of floodwater line and the danger zone. This paper intro duced the analytical process of the flood control capacity of the village along the river to calculate the water level-river discharge relationship in the control section. Moreover, this study also put forward a feasible method of calculating the disaster water level and counting the number of people in the danger zone by point out the projection and judging point-line relationship. For this purpose, a typical village along the river was taken out to calculate the floodwater line and danger zone. The results showed that the applied method could ascertain the household that was the weakest in the aspect of flood control capacity by combining field investigation and the detennined relationship between households and different frequencies of the floodwater line. Therefore, the flood control capacity of the village along the river could calculate accurately.
With the advancement of the prevention of flashflood disasters in the small watershed of the mountainous area，the local key areas ( villages and towns) along the river in hilly areas have become the focus of flash flood disasters. It is critical anddifficult to analyze and to calculate the risk of each village along the river, to determine the unified disaster water level, and to analyze the submersed number of people under different frequencies of floodwater line and the danger zone. This paper intro duced the analytical process of the flood control capacity of the village along the river to calculate the water level-river discharge relationship in the control section. Moreover, this study also put forward a feasible method of calculating the disaster water level and counting the number of people in the danger zone by point out the projection and judging point-line relationship. For this purpose, a typical village along the river was taken out to calculate the floodwater line and danger zone. The results showed that the applied method could ascertain the household that was the weakest in the aspect of flood control capacity by combining field investigation and the detennined relationship between households and different frequencies of the floodwater line. Therefore, the flood control capacity of the village along the river could calculate accurately.
2020, 18(3):127-141.
Abstract:
Self-purification ability of the water body is an in1portant factor affecting the change in 'Nater quality indicators. In this study, the self purification capability was characterized hy the BOD, degradation coefficient. From January 2015 to July 2015, six monitoring sections (Chenggou,Fangcheng,Shahenan, Lanhehei,Xinfeng,and Suzhang) of the main canal in the middle route of the south to North Water Transfer Project were selected to monitor the BOD5 monthly data and to study the flow and water depth of each control gate in the canal section, the one-dimensional steady BOD5 degradation model was used to fit the BOD5 degradation coefficient of the main channel. The results showed that the degradation coefficients of BOD5, in the channel section between 0.024/d～0.054/d. The capacity of water self-purification of the main channel is relatively small compared to other areas. The seasonal change of the BOD5, degradation coefficient in the channel section was obvious. The fitting k values from January to April and July were0.028/d（p＜O.O5)，0.033/d（p〈0.05)，0.024 /d（p＜O.O5，0.039 /d(p
Self-purification ability of the water body is an in1portant factor affecting the change in 'Nater quality indicators. In this study, the self purification capability was characterized hy the BOD, degradation coefficient. From January 2015 to July 2015, six monitoring sections (Chenggou,Fangcheng,Shahenan, Lanhehei,Xinfeng,and Suzhang) of the main canal in the middle route of the south to North Water Transfer Project were selected to monitor the BOD5 monthly data and to study the flow and water depth of each control gate in the canal section, the one-dimensional steady BOD5 degradation model was used to fit the BOD5 degradation coefficient of the main channel. The results showed that the degradation coefficients of BOD5, in the channel section between 0.024/d～0.054/d. The capacity of water self-purification of the main channel is relatively small compared to other areas. The seasonal change of the BOD5, degradation coefficient in the channel section was obvious. The fitting k values from January to April and July were0.028/d（p＜O.O5)，0.033/d（p〈0.05)，0.024 /d（p＜O.O5，0.039 /d(p
2020, 18(3):142-150.
Abstract:
The single factor evaluation method and the comprehensive pollution index (CPI) method were employed to evaluate the water quality of 31 ditches around the Yuqiao Resvervoir in 2017. The single factor evaluation results showed that the proportion of Ⅲ and the lower V were 9. 5% and 52.4%, respectively. The main pollution factors were ammonia nitrogen, total phosphorus, and chemical oxygen demand. The comprehensive pollution index results showed that the worst water quality was Yangezhuang ditch with CP1=48. 67 and the best was Yingzhuangzi ditch with CPI= 1. 45, respectively, Based on meteorology date，such as rainfall, hydrological data,topographic information, soil and land use records were collected to simulate the surface runoff of the ditches using SCS-CN method. Furthermore, the pollution load of the main pollutants was estimated after multipl ymghy the concentration of the pollutant. The results indicated that the annual input of chemical oxygen demand was 723. 2 tons,and total nitrogen was 213. 9 tons,while total phosphorus was 11. 4 tons, respectively. The research result would provide scientific evidence for strengthening the water quality safeguarding and non-point source pollution controlling of Yuqiao Reser voir, which moy benefit form reducing the reservoir inflow pollutants and ensuring the drinking water resource safety.
The single factor evaluation method and the comprehensive pollution index (CPI) method were employed to evaluate the water quality of 31 ditches around the Yuqiao Resvervoir in 2017. The single factor evaluation results showed that the proportion of Ⅲ and the lower V were 9. 5% and 52.4%, respectively. The main pollution factors were ammonia nitrogen, total phosphorus, and chemical oxygen demand. The comprehensive pollution index results showed that the worst water quality was Yangezhuang ditch with CP1=48. 67 and the best was Yingzhuangzi ditch with CPI= 1. 45, respectively, Based on meteorology date，such as rainfall, hydrological data,topographic information, soil and land use records were collected to simulate the surface runoff of the ditches using SCS-CN method. Furthermore, the pollution load of the main pollutants was estimated after multipl ymghy the concentration of the pollutant. The results indicated that the annual input of chemical oxygen demand was 723. 2 tons,and total nitrogen was 213. 9 tons,while total phosphorus was 11. 4 tons, respectively. The research result would provide scientific evidence for strengthening the water quality safeguarding and non-point source pollution controlling of Yuqiao Reser voir, which moy benefit form reducing the reservoir inflow pollutants and ensuring the drinking water resource safety.
14 Study on the effect of ecological water supplement on water quality and quantity in Chengnan River
2020, 18(3):151-157.
Abstract:
In order to improve the low discharge, low water level, insufficient hydrodynamic force and serious water pollution in urban rivers during the dry season, the effect of ecological water supplement schemes in the Chengnan River of Nanjing City was studied. By comprehensively considering the water quality conditions of the upstream and downstream, and the tributaries in the dry season, the water supplement scheme was set up according to the difference of water supplement quantity and mode (inclu_x005f ding intermittent water supplement and continuous water supplement). The coupling model of water quantity and quality of MIKE11 was established in the study area. The changes of pollutant COD,NHs-N,TP reduction rate and velocity distribution under different water supplement schemes were simulated and analyzed. The effect of different ecological water supplement schemes was obtained. The results showed that with the increase of water supplement, the concentration of pollutants decrease rate was fast and then slow. The intermittent water supplement scheme was better than the continuous water supplement scheme. Ecological water supplement had a significant effect on reducing pollutant concentration, but the improvement of the water quality in the long and tortuous river was not obvious. The effect of ecological water supplement on the improvement of the velocity distribution was obvious, but due to the influence the river structure,careful consideration needed to be made to de termine the water supplement point.
In order to improve the low discharge, low water level, insufficient hydrodynamic force and serious water pollution in urban rivers during the dry season, the effect of ecological water supplement schemes in the Chengnan River of Nanjing City was studied. By comprehensively considering the water quality conditions of the upstream and downstream, and the tributaries in the dry season, the water supplement scheme was set up according to the difference of water supplement quantity and mode (inclu_x005f ding intermittent water supplement and continuous water supplement). The coupling model of water quantity and quality of MIKE11 was established in the study area. The changes of pollutant COD,NHs-N,TP reduction rate and velocity distribution under different water supplement schemes were simulated and analyzed. The effect of different ecological water supplement schemes was obtained. The results showed that with the increase of water supplement, the concentration of pollutants decrease rate was fast and then slow. The intermittent water supplement scheme was better than the continuous water supplement scheme. Ecological water supplement had a significant effect on reducing pollutant concentration, but the improvement of the water quality in the long and tortuous river was not obvious. The effect of ecological water supplement on the improvement of the velocity distribution was obvious, but due to the influence the river structure,careful consideration needed to be made to de termine the water supplement point.
2020, 18(3):158-167.
Abstract:
Aiming at the thermal stratification characteristics of plain reservoirs and their impact on water quality, a vertical two- dimensional water temperature model was developed using the CE-QUAL-W2 model to simulate the characteristics of water temperature changes throughout 2018. The absolute mean error of the three calibration sections was 0. 53 °C, 0. 35 °C and 0. 14 °C respectively. The seasonal variation of water temperature and water quality response characteristics of the reservoir were ana lyzed based on simulation results and monitoring dat& A mobile water pump was proposed based on the axial flow pump mixed aeration technology to increase the DO concentration in the bottom of the reservoir. The improvement effects of the mobile water pump on vertical water quality were preliminarily analyzed based on the monitoring data. The results showed that the reser voir presented a singlocycle mixed mode throughout the year (stratified period: May to November, mixed period: December to April). The reservoir formed a stable thermal stratification structure in summer and formed a hypolimnion with a thickness of a- bout 8 m anoxic zone (DO concentration is less than 2 mg/L). The release amount of pollutants (iron, manganese , total nitro gen, total phosphorus, COD, ammonia nitrogen, and so on) in hypolimnion was much larger than the epilimnion and the thermo cline because of the anaerobic environment. The mobile water pump can effectively improve DO concentration in the hypolimnion and weaken the thermal stratification structure (the DO concentration in the working center increased from 0. 2 mg/L to 0. 8 mg/L,and the thermocline thickness decreased by 4 m).
Aiming at the thermal stratification characteristics of plain reservoirs and their impact on water quality, a vertical two- dimensional water temperature model was developed using the CE-QUAL-W2 model to simulate the characteristics of water temperature changes throughout 2018. The absolute mean error of the three calibration sections was 0. 53 °C, 0. 35 °C and 0. 14 °C respectively. The seasonal variation of water temperature and water quality response characteristics of the reservoir were ana lyzed based on simulation results and monitoring dat& A mobile water pump was proposed based on the axial flow pump mixed aeration technology to increase the DO concentration in the bottom of the reservoir. The improvement effects of the mobile water pump on vertical water quality were preliminarily analyzed based on the monitoring data. The results showed that the reser voir presented a singlocycle mixed mode throughout the year (stratified period: May to November, mixed period: December to April). The reservoir formed a stable thermal stratification structure in summer and formed a hypolimnion with a thickness of a- bout 8 m anoxic zone (DO concentration is less than 2 mg/L). The release amount of pollutants (iron, manganese , total nitro gen, total phosphorus, COD, ammonia nitrogen, and so on) in hypolimnion was much larger than the epilimnion and the thermo cline because of the anaerobic environment. The mobile water pump can effectively improve DO concentration in the hypolimnion and weaken the thermal stratification structure (the DO concentration in the working center increased from 0. 2 mg/L to 0. 8 mg/L,and the thermocline thickness decreased by 4 m).
2020, 18(3):168-173.
Abstract:
The water ecological and water environmental factors were sampled to ascertain the health status of the aquatic ecosys tem of Yuehai Lake in YinChuan in winter (January), spring (April), summer (July) and autumn (October) from 2015 to 2017. Nine factors such as chlorophyll (China) , comprehensive nutritional status index (TLI(∑)) , phytoplankton biomass (D), benthic Shannon-Wiener index(H＇Aquatic plant) ,and aquatic plant Shannon-Wiener index(H＇Benthic) , permanganate index (CODmh), total nitrogen (TN), ammonia nitrogen (NH3-N), total phosphorus (TP) were selected to establish evaluation index system u- sing principal component analysis (PCA) for the health assessment of the aquatic ecosystem in Yuehai Lake. The PCA method was used to determine the weight of the index, while the gray relational method was used to evaluate the health level of the a- quatic ecosystem. The results showed that the health assessment grades of the aquatic ecosystems in the spring, summer and au tumn were all sub-health from 2015-2017, whereas in winter, the status was healthy. The extreme level of nitrogen and phos phorus nutrients were the main cause of sub-health in Lake Yuehai from 2015-2017.
The water ecological and water environmental factors were sampled to ascertain the health status of the aquatic ecosys tem of Yuehai Lake in YinChuan in winter (January), spring (April), summer (July) and autumn (October) from 2015 to 2017. Nine factors such as chlorophyll (China) , comprehensive nutritional status index (TLI(∑)) , phytoplankton biomass (D), benthic Shannon-Wiener index(H＇Aquatic plant) ,and aquatic plant Shannon-Wiener index(H＇Benthic) , permanganate index (CODmh), total nitrogen (TN), ammonia nitrogen (NH3-N), total phosphorus (TP) were selected to establish evaluation index system u- sing principal component analysis (PCA) for the health assessment of the aquatic ecosystem in Yuehai Lake. The PCA method was used to determine the weight of the index, while the gray relational method was used to evaluate the health level of the a- quatic ecosystem. The results showed that the health assessment grades of the aquatic ecosystems in the spring, summer and au tumn were all sub-health from 2015-2017, whereas in winter, the status was healthy. The extreme level of nitrogen and phos phorus nutrients were the main cause of sub-health in Lake Yuehai from 2015-2017.
2020, 18(3):174-183.
Abstract:
Dragon-raise-head spillway tunnel is widely used in water conservancy and hydropower projects, due to its complex flow pattern at the anti-arch section the cause of cavitation damage is not clear. To better study this problem, this paper carried out three-dimensional numerical calculations on the working conditions of different spillway tunnels before and after aeration and made exploratory research on the distribution law of the hydraulic characteristics. The results showed that with the increase of drop △Z the velocity of flow in the anti-arch section increased, and the number of cavitation decreased gradually. The change of the radius had a limited influence on the hydraulic parameters of the anti-arch section.. The hydraulic parameters at the end of the anti-arc section did not change much before and after aeration when the drop of △Z increased. With the increase of drop △Z,the velocity of aerated flow at 30m(equal to 15 times the height of the flip bucket) downstream of the end of the anti—arc section decreased visibly, and the number of cavitation increased apparently. The protective effect of aerated flow on the hydrau lic parameters at the downstream part of the cavity was more obvious. Secondary flow occurred at the end of the arc,and sym metrical vortices exist near the sidewalls on both sides. The secondary flow phenomenon associated with the flow in the reverse arc section was a characteristic of the flow in the anti-arch section It not only affected the velocity and pressure distribution near the sidewall but also made the hydraulic characteristics in the anti-arch section more complex.
Dragon-raise-head spillway tunnel is widely used in water conservancy and hydropower projects, due to its complex flow pattern at the anti-arch section the cause of cavitation damage is not clear. To better study this problem, this paper carried out three-dimensional numerical calculations on the working conditions of different spillway tunnels before and after aeration and made exploratory research on the distribution law of the hydraulic characteristics. The results showed that with the increase of drop △Z the velocity of flow in the anti-arch section increased, and the number of cavitation decreased gradually. The change of the radius had a limited influence on the hydraulic parameters of the anti-arch section.. The hydraulic parameters at the end of the anti-arc section did not change much before and after aeration when the drop of △Z increased. With the increase of drop △Z,the velocity of aerated flow at 30m(equal to 15 times the height of the flip bucket) downstream of the end of the anti—arc section decreased visibly, and the number of cavitation increased apparently. The protective effect of aerated flow on the hydrau lic parameters at the downstream part of the cavity was more obvious. Secondary flow occurred at the end of the arc,and sym metrical vortices exist near the sidewalls on both sides. The secondary flow phenomenon associated with the flow in the reverse arc section was a characteristic of the flow in the anti-arch section It not only affected the velocity and pressure distribution near the sidewall but also made the hydraulic characteristics in the anti-arch section more complex.
2020, 18(3):184-191.
Abstract:
Taking the risk instability of inverted siphon in the water diversion project as the research objective, considering the complex and dynamic relationship between the four factors such as nature, engineering,man-made and management, a risk analy sis feedback model based on system dynamics was established. The importance of factor which may affect the stability of the in verted siphon project was analyzed. The results of the analytic hierarchy process were used to validate the feedback model. The results showed that the model had good accuracy and applicability, which may provide a new way for risk assessment of water diversion projects in the future.
Taking the risk instability of inverted siphon in the water diversion project as the research objective, considering the complex and dynamic relationship between the four factors such as nature, engineering,man-made and management, a risk analy sis feedback model based on system dynamics was established. The importance of factor which may affect the stability of the in verted siphon project was analyzed. The results of the analytic hierarchy process were used to validate the feedback model. The results showed that the model had good accuracy and applicability, which may provide a new way for risk assessment of water diversion projects in the future.
2020, 18(3):192-200.
Abstract:
In order to improve the flow pattern in the forebay of the side-intake pumping station, the numerical simulations were performed on the forebay of the sidointake pumping station with no rectifying measures and settings of Y-shaped diversion piers using CFX software and RNG ks turbulence model. An analysis of the influence of the position,height,angle, and length of the Y-shaped diversion piers on the improvement of the flow pattern in the forebay of the sidointake pump station were car ried out. Numerical results indicated that if there was no rectification measure, then there was a large area of recirculation in the left area of the forebay of the pumping station. The water flow deflection on the right side of the pumping station was very obvi ous ,which had an adverse effect on the unit. The Y-shaped diversion pier had a shunting effect. The velocity of flow can be sig nificantly uniform by arranging the Y-shaped pier in front of the inlet pool. The recirculation zone could be eliminated? and the water flow could flow into the units more evenly. It was found that the flow pattern in the forebay of the side-intake pumpingstation significantly improved, and the approach velocity distribution before the inlet pool was more uniform when the Y-shaped diversion pier was located at 33. 33D0 in front of the inlet pool and the height was 1. 11DO , the angle was 120°and the length was 2. 78D0，respectively.
In order to improve the flow pattern in the forebay of the side-intake pumping station, the numerical simulations were performed on the forebay of the sidointake pumping station with no rectifying measures and settings of Y-shaped diversion piers using CFX software and RNG ks turbulence model. An analysis of the influence of the position,height,angle, and length of the Y-shaped diversion piers on the improvement of the flow pattern in the forebay of the sidointake pump station were car ried out. Numerical results indicated that if there was no rectification measure, then there was a large area of recirculation in the left area of the forebay of the pumping station. The water flow deflection on the right side of the pumping station was very obvi ous ,which had an adverse effect on the unit. The Y-shaped diversion pier had a shunting effect. The velocity of flow can be sig nificantly uniform by arranging the Y-shaped pier in front of the inlet pool. The recirculation zone could be eliminated? and the water flow could flow into the units more evenly. It was found that the flow pattern in the forebay of the side-intake pumpingstation significantly improved, and the approach velocity distribution before the inlet pool was more uniform when the Y-shaped diversion pier was located at 33. 33D0 in front of the inlet pool and the height was 1. 11DO , the angle was 120°and the length was 2. 78D0，respectively.
2020, 18(3):201-209.
Abstract:
The bibliometric analysis method can quantitatively analyze the research hotspots and development trends for the field of seepage monitoring. The research results showed that the application and research of global seepage monitoring have been in a clear positive trend since 1981, based on available statistics. The observation holes/wells, electrical-resistivity tomography, pie zometer are widely used from 1981. Although optical fiber sensing technology and remote sensing technology started late, they have developed rapidly and gradually matured in recent years. The dam safety, water pollution, agricultural irrigation and soil stability are the research hotspots in the seepage monitoring field, and the multidisciplinary in this field has become an obvious trend. The United States, China, Canada and other countriesz scientific research institutions have made many contributions in the seepage monitoring field at present, and both the volume of publications and the H—index are in a leading position. This article counts the number of publications, H-indexes,and citations of ToplO issue journals, which all come from publishers in the US, the Netherlands, and Canada. The research results may provide a reference for the seepage monitoring of future research and practice.
The bibliometric analysis method can quantitatively analyze the research hotspots and development trends for the field of seepage monitoring. The research results showed that the application and research of global seepage monitoring have been in a clear positive trend since 1981, based on available statistics. The observation holes/wells, electrical-resistivity tomography, pie zometer are widely used from 1981. Although optical fiber sensing technology and remote sensing technology started late, they have developed rapidly and gradually matured in recent years. The dam safety, water pollution, agricultural irrigation and soil stability are the research hotspots in the seepage monitoring field, and the multidisciplinary in this field has become an obvious trend. The United States, China, Canada and other countriesz scientific research institutions have made many contributions in the seepage monitoring field at present, and both the volume of publications and the H—index are in a leading position. This article counts the number of publications, H-indexes,and citations of ToplO issue journals, which all come from publishers in the US, the Netherlands, and Canada. The research results may provide a reference for the seepage monitoring of future research and practice.
2020, 18(3):210-216.
Abstract:
For a new type of bi-directional ultra-low lift pump device which can be used for two-way pumping, the CFX software was used to perform three-dimensional flow numerical simulation. The internal flow characteristics of the pump device were ana lyzed and the overall performance of the pump device was predicted. The calculation results showed that under the designed con dition (flow Q=4. 8 m3/s) and the large flow condition (flow Q=5. 4 m3/s) , the flow velocity uniformity at the impeller inlet section reached about 90%. The flow pattern at the impeller inlet section was good enough to ensure the performance of the wa ter pump. The flow line at the outlet section of the diffusion guide vane was smooth, and the recovery of the flow velocity circu lation by the diffusion guide vane was good. The hydraulic loss of the inlet water of the pump device was small, while the hy draulic loss of the outlet water was large. The device had the highest efficiency (71. 09%) under the designed working condition (flow Q=4. 8 m3/s), while the corresponding lift was 1. 345 m. The flow range in the high-efficiency zone of the pump device was relatively large,and the highest efficiency exceeded the existing low-lift pump device of the same type by more than 5%. The new type of bi-directional ultra—low lift pump device was a desirable scheme in the riverside and lakeside areas along the river where gravity drainage and the actual lift was very low.
For a new type of bi-directional ultra-low lift pump device which can be used for two-way pumping, the CFX software was used to perform three-dimensional flow numerical simulation. The internal flow characteristics of the pump device were ana lyzed and the overall performance of the pump device was predicted. The calculation results showed that under the designed con dition (flow Q=4. 8 m3/s) and the large flow condition (flow Q=5. 4 m3/s) , the flow velocity uniformity at the impeller inlet section reached about 90%. The flow pattern at the impeller inlet section was good enough to ensure the performance of the wa ter pump. The flow line at the outlet section of the diffusion guide vane was smooth, and the recovery of the flow velocity circu lation by the diffusion guide vane was good. The hydraulic loss of the inlet water of the pump device was small, while the hy draulic loss of the outlet water was large. The device had the highest efficiency (71. 09%) under the designed working condition (flow Q=4. 8 m3/s), while the corresponding lift was 1. 345 m. The flow range in the high-efficiency zone of the pump device was relatively large,and the highest efficiency exceeded the existing low-lift pump device of the same type by more than 5%. The new type of bi-directional ultra—low lift pump device was a desirable scheme in the riverside and lakeside areas along the river where gravity drainage and the actual lift was very low.
2020, 18(3):217-224.
Abstract:
River ice thickness is an important indicator of ice prevention. At present, the ice thickness is measured by drilling or contact-type GPR required stably freeze-up. Therefore, it is of great significance to actively explore more efficient non-contact ice thickness detection methods. The UAV was equipped with the GPR to detect the ice thickness of the Shensifenzi bend of the Yellow River. The radar propagation velocity in the ice was calculated by using ice thickness data from the field of artificial drill ing. The results showed that the distribution of ice thickness at the bend was uneven. The ice thickness on the concave bank was larger than that on the convex bank. The maximum ice thickness of the lead section was 91cm, the minimum ice thickness of the lead section was 19cm, and the ice thickness near the water surface was small. The ice thickness measured by radar was basically consistent with the measured by drilling, and the average error was less than 2 cm. The practice has proved that UAV radar im ages can directly reflect the air-ice interface and ice-water interface and ice thickness. The detection method has fast advantages, high efficiency and safety. The research results have important reference value for the development of new monitoring of the Yellow River ice thickness.
River ice thickness is an important indicator of ice prevention. At present, the ice thickness is measured by drilling or contact-type GPR required stably freeze-up. Therefore, it is of great significance to actively explore more efficient non-contact ice thickness detection methods. The UAV was equipped with the GPR to detect the ice thickness of the Shensifenzi bend of the Yellow River. The radar propagation velocity in the ice was calculated by using ice thickness data from the field of artificial drill ing. The results showed that the distribution of ice thickness at the bend was uneven. The ice thickness on the concave bank was larger than that on the convex bank. The maximum ice thickness of the lead section was 91cm, the minimum ice thickness of the lead section was 19cm, and the ice thickness near the water surface was small. The ice thickness measured by radar was basically consistent with the measured by drilling, and the average error was less than 2 cm. The practice has proved that UAV radar im ages can directly reflect the air-ice interface and ice-water interface and ice thickness. The detection method has fast advantages, high efficiency and safety. The research results have important reference value for the development of new monitoring of the Yellow River ice thickness.
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