Volume 20,Issue 1,2022 Table of Contents
2022, 20(1):1-8.
Abstract:
Based on the brief introduction of water science and human-water relationship discipline,the conclusion that the research of humanwater relationship is the core and nexus of water science was put forward,the conclusion was discussed from the case studies of human-water relationship in 10 branches of water science.In view of the four focus issues of the demonstration of trans-basin water transfer project,the construction of water conservancy projects on major rivers,the prevention and control of floods and droughts,and the water distribution of trans-boundary rivers,the misunderstandings and solutions of the above four focus issues are expounded from the perspective of human-water relationship research,which can provide a new discipline idea for solving these complex issues.
Based on the brief introduction of water science and human-water relationship discipline,the conclusion that the research of humanwater relationship is the core and nexus of water science was put forward,the conclusion was discussed from the case studies of human-water relationship in 10 branches of water science.In view of the four focus issues of the demonstration of trans-basin water transfer project,the construction of water conservancy projects on major rivers,the prevention and control of floods and droughts,and the water distribution of trans-boundary rivers,the misunderstandings and solutions of the above four focus issues are expounded from the perspective of human-water relationship research,which can provide a new discipline idea for solving these complex issues.
2022, 20(1):9-20.
Abstract:
The imbalance of water supply and demand,over-exploitation of groundwater,water pollution,water ecological damage,and other issues have become increasingly prominent under the strong influence of climate warming and human activities.Water resources have become an important factor restricting the sustainable development of the regional economy and society and the health and stability of the ecological environment.Research on the carrying capacity of water resources is of great significance for realizing the coordinated development of water resources,economic society,and ecological environment.In March 2018,the State Council officially approved that Taiyuan should take steps for the transformation and upgrading of resource-based cities as the theme,build an innovative demonstration area of the national sustainable development agenda,implement water resource conservation and water environment reconstruction,and explore systematic solutions to major problems restricting sustainable development.However,Taiyuan is a typical resourcebased city in China,with low per capita water resources,a serious historical debt of groundwater overexploitation,serious water pollution,and water ecological damage.Water resources have become an important ′bottleneck′ restricting its ecological environment protection and high-quality development.Therefore,it is national and local major practical needs to evaluate water resources carrying capacity in Taiyuan City based on the analysis of multidimensional carrying elements of water resources,to provide technical support and decision support for the transformation and upgrading and high-quality development of resource-based cities in Taiyuan City. Based on the analysis of multidimensional carrying elements of water resources,the evaluation index system of water resources carrying capacity was constructed from four dimensions of quantity-quality-domain-flow.The weight of evaluation index was determined by the combination weighting method of AHP and entropy weight method,and the water resources carrying capacity evaluation model based on SMI-P method was established. The evaluation index system and model were applied for the assessment of water resources carrying capacity in Taiyuan.The results indicated that the comprehensive carrying capacity of water resources in Taiyuan was overloaded from 2009 to 2018.From the four dimensions of water resources quantity-quality-watershed-flow,the carrying capacity index of each dimension is on the rise.The carrying state of water quantity dimension changed from overload to critical overload,the carrying state of water quality dimension changed from serious overload to overload,the carrying state of watershed dimension changed from serious overload to overload,and the carrying state of water flow dimension changed from overload to critical overload. Despite the continuous improvement of water resources in Taiyuan City,the tasks of water pollution control,water ecological environment protection,alleviating water conflicts,and improving water use efficiency in Taiyuan City are still very difficult.The problems of resource constraints,ecological function degradation,low environmental carrying capacity,uncoordinated development,and unsustainable development in Taiyuan City are still prominent.In the future,the protection of the water ecological environment in Taiyuan should focus on sewage treatment,wetland restoration,soil and water loss control,which mainly improves the carrying capacity of water quality and watershed dimension.The conclusions of this study can provide technical support and decision support for the transformation and upgrading and high-quality development of resource-based cities in Taiyuan.
The imbalance of water supply and demand,over-exploitation of groundwater,water pollution,water ecological damage,and other issues have become increasingly prominent under the strong influence of climate warming and human activities.Water resources have become an important factor restricting the sustainable development of the regional economy and society and the health and stability of the ecological environment.Research on the carrying capacity of water resources is of great significance for realizing the coordinated development of water resources,economic society,and ecological environment.In March 2018,the State Council officially approved that Taiyuan should take steps for the transformation and upgrading of resource-based cities as the theme,build an innovative demonstration area of the national sustainable development agenda,implement water resource conservation and water environment reconstruction,and explore systematic solutions to major problems restricting sustainable development.However,Taiyuan is a typical resourcebased city in China,with low per capita water resources,a serious historical debt of groundwater overexploitation,serious water pollution,and water ecological damage.Water resources have become an important ′bottleneck′ restricting its ecological environment protection and high-quality development.Therefore,it is national and local major practical needs to evaluate water resources carrying capacity in Taiyuan City based on the analysis of multidimensional carrying elements of water resources,to provide technical support and decision support for the transformation and upgrading and high-quality development of resource-based cities in Taiyuan City. Based on the analysis of multidimensional carrying elements of water resources,the evaluation index system of water resources carrying capacity was constructed from four dimensions of quantity-quality-domain-flow.The weight of evaluation index was determined by the combination weighting method of AHP and entropy weight method,and the water resources carrying capacity evaluation model based on SMI-P method was established. The evaluation index system and model were applied for the assessment of water resources carrying capacity in Taiyuan.The results indicated that the comprehensive carrying capacity of water resources in Taiyuan was overloaded from 2009 to 2018.From the four dimensions of water resources quantity-quality-watershed-flow,the carrying capacity index of each dimension is on the rise.The carrying state of water quantity dimension changed from overload to critical overload,the carrying state of water quality dimension changed from serious overload to overload,the carrying state of watershed dimension changed from serious overload to overload,and the carrying state of water flow dimension changed from overload to critical overload. Despite the continuous improvement of water resources in Taiyuan City,the tasks of water pollution control,water ecological environment protection,alleviating water conflicts,and improving water use efficiency in Taiyuan City are still very difficult.The problems of resource constraints,ecological function degradation,low environmental carrying capacity,uncoordinated development,and unsustainable development in Taiyuan City are still prominent.In the future,the protection of the water ecological environment in Taiyuan should focus on sewage treatment,wetland restoration,soil and water loss control,which mainly improves the carrying capacity of water quality and watershed dimension.The conclusions of this study can provide technical support and decision support for the transformation and upgrading and high-quality development of resource-based cities in Taiyuan.
2022, 20(1):21-29.
Abstract:
With the rapid development of urbanization,the impervious surface of cities and towns significantly increases,which causes the change of hydrological process and the increase of flood events.Due to the special construction properties of industrial parks,the impervious area is much larger than previous area,so it is easy to cause waterlogging disasters and runoff pollution in the industrial zone.Low impact development (LID) facilities can effectively alleviate urban waterlogging and improve the urban water ecological environment. Impact of different LID combinations on rainwater source control and pollution load reduction,taking an industrial park in Huainan City as the research object.Five LID combination schemes were constructed by the SWMM model.In different return periods,the water quantity and quality of five schemes were simulated,and the reduction effects of different schemes on runoff volume,runoff coefficient,peak discharge,and pollutant concentration were analyzed.Methods of the life cycle cost and the benefit monetization were used to calculate and monetize the economic benefits of every kind of LID combination scheme,and the return on investment also was compared to the five different schemes to select the most appropriate LID combination scheme. The results show that the combination of green roofs,rainwater tanks,rainwater gardens,and permeable pavements has the best reduction effect on runoff and pollutants concentration,and the combination of green roofs,rainwater tanks,vegetative swales,and permeable pavements has the best reduction effect on peak flow.The combination of rainwater tanks,rainwater gardens,and permeable pavements has the highest investment return based on cost-benefit analysis.Different LID schemes have a certain reduction effect on water quality and quantity,however,the reduction effect decreases to different degrees with rainfall return period increase.Different LID schemes all have a considerable return on investment,but the addition of green roofs reduces the return on investment of the combination,resulting in the low return on investment for the combination with green roofs. Adding LID facilities has a significant reduction effect on runoff and flood peaks in the study area.Even if the simplest rainwater tanks and vegetative swales are added,the reduction rate of runoff can reach about 11% and one of flood peak discharge can reach about 30%.However,with the increase of rainfall return period,the reduction rate decreases,so more LID facilities need to be added.Vegetative swales have a better effect on reducing peak discharge,and rainwater gardens have a more obvious effect on runoff reduction.Although the addition of green roofs can reduce more runoff and peak flow,the effect of the rainfall return period is more obvious.While the rainfall return period increases,the reduction rate of peak flow decreases to a certain extent.Life cycle cost analysis and benefit monetization analysis show that rainwater gardens can well improve the rate of return on investment,and green roofs have a certain effect on the reduction of runoff and pollutants,but the high investment cost and maintenance cost of green roofs lead to a low rate of return on investment.The combination scheme of green roofs,rainwater tanks,rainwater gardens,and permeable pavements has the highest comprehensive benefit and is more suitable for the planning and construction of industrial parks.
With the rapid development of urbanization,the impervious surface of cities and towns significantly increases,which causes the change of hydrological process and the increase of flood events.Due to the special construction properties of industrial parks,the impervious area is much larger than previous area,so it is easy to cause waterlogging disasters and runoff pollution in the industrial zone.Low impact development (LID) facilities can effectively alleviate urban waterlogging and improve the urban water ecological environment. Impact of different LID combinations on rainwater source control and pollution load reduction,taking an industrial park in Huainan City as the research object.Five LID combination schemes were constructed by the SWMM model.In different return periods,the water quantity and quality of five schemes were simulated,and the reduction effects of different schemes on runoff volume,runoff coefficient,peak discharge,and pollutant concentration were analyzed.Methods of the life cycle cost and the benefit monetization were used to calculate and monetize the economic benefits of every kind of LID combination scheme,and the return on investment also was compared to the five different schemes to select the most appropriate LID combination scheme. The results show that the combination of green roofs,rainwater tanks,rainwater gardens,and permeable pavements has the best reduction effect on runoff and pollutants concentration,and the combination of green roofs,rainwater tanks,vegetative swales,and permeable pavements has the best reduction effect on peak flow.The combination of rainwater tanks,rainwater gardens,and permeable pavements has the highest investment return based on cost-benefit analysis.Different LID schemes have a certain reduction effect on water quality and quantity,however,the reduction effect decreases to different degrees with rainfall return period increase.Different LID schemes all have a considerable return on investment,but the addition of green roofs reduces the return on investment of the combination,resulting in the low return on investment for the combination with green roofs. Adding LID facilities has a significant reduction effect on runoff and flood peaks in the study area.Even if the simplest rainwater tanks and vegetative swales are added,the reduction rate of runoff can reach about 11% and one of flood peak discharge can reach about 30%.However,with the increase of rainfall return period,the reduction rate decreases,so more LID facilities need to be added.Vegetative swales have a better effect on reducing peak discharge,and rainwater gardens have a more obvious effect on runoff reduction.Although the addition of green roofs can reduce more runoff and peak flow,the effect of the rainfall return period is more obvious.While the rainfall return period increases,the reduction rate of peak flow decreases to a certain extent.Life cycle cost analysis and benefit monetization analysis show that rainwater gardens can well improve the rate of return on investment,and green roofs have a certain effect on the reduction of runoff and pollutants,but the high investment cost and maintenance cost of green roofs lead to a low rate of return on investment.The combination scheme of green roofs,rainwater tanks,rainwater gardens,and permeable pavements has the highest comprehensive benefit and is more suitable for the planning and construction of industrial parks.
2022, 20(1):30-39.
Abstract:
The continuous decline of groundwater level in northern China,the thickness of vadose zone continued to increase,so the law of water movement in the vadose zone has changed significantly.The maximum depth of previous experiments and researches on the vadose zone was mostly 7-10 m.Due to the lack of research on the law of water movement and precipitation recharge in the deep vadose zone,lag effect of deep water movement and the process of groundwater recharge problems have not been well solved. A significant research has been carried out on geological drilling in the typical deep vadose zone of the piedmont plain of North China.During drilling,a built-in ring knife sampler was installed at the front of the sampling drill pipe,and a built-in ring knife was pressed into the soil by a non-circulating hydraulic method.The rotary drill pipe disconnected the bottom soil mass and the built-in ring knife sampler simultaneously consolidated the soil sample during sampling to obtain deep undisturbed soil samples with high integrity.The soil structure parameters,water content,and chloride concentration of undisturbed soil samples were tested,and the chloride ion tracing method was used to study the law of water movement in the 45m thick vadose zone.At the same time,the history of precipitation recharge in the deep vadose zone was reconstructed and the intensity of precipitation recharge was evaluated. The results show that :(1) At different depths of vadose zone profile,the chlorine content in soil water is significantly different,and negatively correlated with water content.(2)There are three chloride ion peaks in the depth range of 5.50-28.25 m at the profile of the vadose zone.The first chloride ion peak was affected by evapotranspiration in the semiarid area.The formation of the second and third chloride ion peaks was related to precipitation and the lithologic structure of the vadose zone,which reflected two dry precipitation periods in the recharge history,and the peak mainly occurred in the transition section from coarse-grained stratum to fine-grained stratum.(3) The total age of precipitation recharge recorded in the 45 m vadose zone section was 72.12 years.During this period,the recharge intensity experienced three high and low fluctuations,reflected three relatively dry and wet climate processes.Meanwhile,the average infiltration recharge intensity was 0.096 m/a,and the precipitation infiltration recharge accounted for 18.1% of the average annual precipitation. The vertical infiltration law of water in the deep vadose zone was multiple pulses under the superposition of precipitation and gradually move to the deep,so it need a long-term process to recharge groundwater.When the upper part of the vadose zone was coarse and the lower part was fine,the water migration was hindered and the ion components were accumulated.On the contrary,the water migration was faster and the accumulation of ionic components was less.
The continuous decline of groundwater level in northern China,the thickness of vadose zone continued to increase,so the law of water movement in the vadose zone has changed significantly.The maximum depth of previous experiments and researches on the vadose zone was mostly 7-10 m.Due to the lack of research on the law of water movement and precipitation recharge in the deep vadose zone,lag effect of deep water movement and the process of groundwater recharge problems have not been well solved. A significant research has been carried out on geological drilling in the typical deep vadose zone of the piedmont plain of North China.During drilling,a built-in ring knife sampler was installed at the front of the sampling drill pipe,and a built-in ring knife was pressed into the soil by a non-circulating hydraulic method.The rotary drill pipe disconnected the bottom soil mass and the built-in ring knife sampler simultaneously consolidated the soil sample during sampling to obtain deep undisturbed soil samples with high integrity.The soil structure parameters,water content,and chloride concentration of undisturbed soil samples were tested,and the chloride ion tracing method was used to study the law of water movement in the 45m thick vadose zone.At the same time,the history of precipitation recharge in the deep vadose zone was reconstructed and the intensity of precipitation recharge was evaluated. The results show that :(1) At different depths of vadose zone profile,the chlorine content in soil water is significantly different,and negatively correlated with water content.(2)There are three chloride ion peaks in the depth range of 5.50-28.25 m at the profile of the vadose zone.The first chloride ion peak was affected by evapotranspiration in the semiarid area.The formation of the second and third chloride ion peaks was related to precipitation and the lithologic structure of the vadose zone,which reflected two dry precipitation periods in the recharge history,and the peak mainly occurred in the transition section from coarse-grained stratum to fine-grained stratum.(3) The total age of precipitation recharge recorded in the 45 m vadose zone section was 72.12 years.During this period,the recharge intensity experienced three high and low fluctuations,reflected three relatively dry and wet climate processes.Meanwhile,the average infiltration recharge intensity was 0.096 m/a,and the precipitation infiltration recharge accounted for 18.1% of the average annual precipitation. The vertical infiltration law of water in the deep vadose zone was multiple pulses under the superposition of precipitation and gradually move to the deep,so it need a long-term process to recharge groundwater.When the upper part of the vadose zone was coarse and the lower part was fine,the water migration was hindered and the ion components were accumulated.On the contrary,the water migration was faster and the accumulation of ionic components was less.
2022, 20(1):40-53.
Abstract:
In the context of ecology,river connectivity refers to the smoothness of the transfer and diffusion of materials,energy and organisms among the various components of the river system.With the development of society and economy,the rapid human development and utilization of water resources has led to the decline of water systems and obstructed river connectivity in many river basins,which has seriously affected the function of rivers,such as maintaining the water body′s capacity of holding pollution and self-purification,ensuring the habitat of aquatic organisms and fish migration.As an important area of the national future development strategy,conducting evaluation and analysis about longitudinal connectivity of rivers within the Yangtze River basin to reveal its temporal and spatial evolution characteristics has great significance to the future construction of water conservancy projects and the protection and restoration of water ecosystems. Three different evaluation methods are adopted to explore the evolution characteristics of the rivers longitudinal connectivity within Yangtze River basin by taking construction data of four types of river blocking structures including reservoirs, hydropow-er stations,sluices,and rubberdams. Among them,the barrier coefficient method focuses on barrier characteristics of blocking structures on material flow,biological flow,energy flow,and information flow.The longest continuous reach ratio method focuses on embodying the distribution characteristics of blocking structures and their impact on suitable habitat areas for aquatic organisms represented by fish.The regional overall method focuses on the overall evaluation of the river′s longitudinal connectivity of the water resources regions（class Ⅱ）within the Yangtze River basin. Evaluation results of barrier coefficient method： among the 45 major rivers,in 1960,except Fu River and Xin Jiang,the longitudinal connectivity of the other 43 major rivers are rated as excellent.In 1980,37 rivers are rated as excellent,in 2000,there are 9 rivers with poor longitudinal connectivity while in 2018,the number has increased to 30.Evaluation results of the longest continuous reach ratio method： among the 45 major rivers,in 1960,the longitudinal connectivity of 41 rivers are rated as excellent.In 1980,there are 27 rivers with excellent evaluation grades.In 2000,there are 14 rivers with inferior evaluation grades.In 2018,there were 15 rivers each with poor evaluation grades.Evaluation results of the regional overall method： among the 12 water resources regions (class Ⅱ),in 1960,12 water resources regions (class Ⅱ) have excellent evaluation grades.In 1980 and 2000,there are 7 water resources regions(class Ⅱ) with excellent evaluation grades.In 2018,there are 3 water resources regions(class Ⅱ) with poor evaluation grades. The evaluation results of the barrier coefficient method and the longest continuous reach ratio method show that:In the time dimension,the longitudinal connectivity of rivers within the Yangtze River basin has gradually declined in the past 60 years,and the deterioration of longitudinal connectivity from 2000 to 2018 was the most significant,In spatial distribution,rivers with inferior evaluation grades are mainly distributed in three water resources regions (class Ⅱ)including Mintuo River water resources region,Jialing River water resources region,and Dongting Lake water resources region.The evaluation results of the regional method show that the longitudinal connectivity of the water resources regions (class Ⅱ) within Yangtze River basin deteriorated integrally in 2000-2018,and the overall regional connectivity of the western part of the Yangtze River basin is less damaged by the river blocking structures than the eastern part.Compared with large and medium-sized water conservancy projects,small water conservancy projects have more damage to the longitudinal connectivity.It is recommended to withdraw from the small hydropower stations in the Yangtze River basin in a reasonable and orderly manner.
In the context of ecology,river connectivity refers to the smoothness of the transfer and diffusion of materials,energy and organisms among the various components of the river system.With the development of society and economy,the rapid human development and utilization of water resources has led to the decline of water systems and obstructed river connectivity in many river basins,which has seriously affected the function of rivers,such as maintaining the water body′s capacity of holding pollution and self-purification,ensuring the habitat of aquatic organisms and fish migration.As an important area of the national future development strategy,conducting evaluation and analysis about longitudinal connectivity of rivers within the Yangtze River basin to reveal its temporal and spatial evolution characteristics has great significance to the future construction of water conservancy projects and the protection and restoration of water ecosystems. Three different evaluation methods are adopted to explore the evolution characteristics of the rivers longitudinal connectivity within Yangtze River basin by taking construction data of four types of river blocking structures including reservoirs, hydropow-er stations,sluices,and rubberdams. Among them,the barrier coefficient method focuses on barrier characteristics of blocking structures on material flow,biological flow,energy flow,and information flow.The longest continuous reach ratio method focuses on embodying the distribution characteristics of blocking structures and their impact on suitable habitat areas for aquatic organisms represented by fish.The regional overall method focuses on the overall evaluation of the river′s longitudinal connectivity of the water resources regions（class Ⅱ）within the Yangtze River basin. Evaluation results of barrier coefficient method： among the 45 major rivers,in 1960,except Fu River and Xin Jiang,the longitudinal connectivity of the other 43 major rivers are rated as excellent.In 1980,37 rivers are rated as excellent,in 2000,there are 9 rivers with poor longitudinal connectivity while in 2018,the number has increased to 30.Evaluation results of the longest continuous reach ratio method： among the 45 major rivers,in 1960,the longitudinal connectivity of 41 rivers are rated as excellent.In 1980,there are 27 rivers with excellent evaluation grades.In 2000,there are 14 rivers with inferior evaluation grades.In 2018,there were 15 rivers each with poor evaluation grades.Evaluation results of the regional overall method： among the 12 water resources regions (class Ⅱ),in 1960,12 water resources regions (class Ⅱ) have excellent evaluation grades.In 1980 and 2000,there are 7 water resources regions(class Ⅱ) with excellent evaluation grades.In 2018,there are 3 water resources regions(class Ⅱ) with poor evaluation grades. The evaluation results of the barrier coefficient method and the longest continuous reach ratio method show that:In the time dimension,the longitudinal connectivity of rivers within the Yangtze River basin has gradually declined in the past 60 years,and the deterioration of longitudinal connectivity from 2000 to 2018 was the most significant,In spatial distribution,rivers with inferior evaluation grades are mainly distributed in three water resources regions (class Ⅱ)including Mintuo River water resources region,Jialing River water resources region,and Dongting Lake water resources region.The evaluation results of the regional method show that the longitudinal connectivity of the water resources regions (class Ⅱ) within Yangtze River basin deteriorated integrally in 2000-2018,and the overall regional connectivity of the western part of the Yangtze River basin is less damaged by the river blocking structures than the eastern part.Compared with large and medium-sized water conservancy projects,small water conservancy projects have more damage to the longitudinal connectivity.It is recommended to withdraw from the small hydropower stations in the Yangtze River basin in a reasonable and orderly manner.
2022, 20(1):54-61.
Abstract:
The safety of water diversion project is a public safety problem related to the national economy and people's livelihood,and the monitoring index is the scientific criterion to ensure the project operation safety.The quantitative monitoring index defined the safety boundary in the form of numerical value and tendency of the monitoring effect variables,but it focused on a single monitoring point and the local behavior.It was difficult to monitor the overall safety behavior of the canal by the quantitative monitoring index for a single monitoring point because the line of the canal was too long,and the construction and operation conditions of canal ware complex in water diversion project,so it is necessary to establish the qualitative evaluation criteria to provide a scientific basis for canal safety evaluation based on multi-source information. The abnormal phenomenon of a single monitoring point was the basis of establishing qualitative evaluation criteria,to be summarized as monitoring value,variation process,variation trend,and variation regularity.The abnormal value of a single monitoring point did not mean the operation behavior of the monitoring section or the monitoring area were abnormal.To assess the overall operation behavior of the canal,multi-point information was used in combination.The qualitative evaluation criteria of canal safety with multi-point information were established based on the study of the correlations of monitoring information among different monitoring points on the same monitoring section or monitoring area,which included the correlation in abnormal performance and distribution of multi-monitoring points. Deformation,seepage,stress,and strain ware occur under the action of various load combinations during the operation of the canal,and these effect variables described the operation behavior of the canal from different angles.The qualitative evaluation criteria of canal safety with multi-monitoring effect variables information were established based on the analysis of interaction and mutual influence and the study on the correlations among different effect variables. The qualitative evaluation criteria of canal safety with the information from field inspection were established based on the analysis of the working mechanism of the canal with different characteristics and the study on the outward manifestation of the working mechanism.The qualitative evaluation criterion was an important form of safety monitoring index of the canal and played a specially important role in canal safety monitoring.Operation safety of the canal in water diversion projects can be more safeguarded by the combination of qualitative safety evaluation criteria and quantitative numerical monitoring index.
The safety of water diversion project is a public safety problem related to the national economy and people's livelihood,and the monitoring index is the scientific criterion to ensure the project operation safety.The quantitative monitoring index defined the safety boundary in the form of numerical value and tendency of the monitoring effect variables,but it focused on a single monitoring point and the local behavior.It was difficult to monitor the overall safety behavior of the canal by the quantitative monitoring index for a single monitoring point because the line of the canal was too long,and the construction and operation conditions of canal ware complex in water diversion project,so it is necessary to establish the qualitative evaluation criteria to provide a scientific basis for canal safety evaluation based on multi-source information. The abnormal phenomenon of a single monitoring point was the basis of establishing qualitative evaluation criteria,to be summarized as monitoring value,variation process,variation trend,and variation regularity.The abnormal value of a single monitoring point did not mean the operation behavior of the monitoring section or the monitoring area were abnormal.To assess the overall operation behavior of the canal,multi-point information was used in combination.The qualitative evaluation criteria of canal safety with multi-point information were established based on the study of the correlations of monitoring information among different monitoring points on the same monitoring section or monitoring area,which included the correlation in abnormal performance and distribution of multi-monitoring points. Deformation,seepage,stress,and strain ware occur under the action of various load combinations during the operation of the canal,and these effect variables described the operation behavior of the canal from different angles.The qualitative evaluation criteria of canal safety with multi-monitoring effect variables information were established based on the analysis of interaction and mutual influence and the study on the correlations among different effect variables. The qualitative evaluation criteria of canal safety with the information from field inspection were established based on the analysis of the working mechanism of the canal with different characteristics and the study on the outward manifestation of the working mechanism.The qualitative evaluation criterion was an important form of safety monitoring index of the canal and played a specially important role in canal safety monitoring.Operation safety of the canal in water diversion projects can be more safeguarded by the combination of qualitative safety evaluation criteria and quantitative numerical monitoring index.
2022, 20(1):62-69.
Abstract:
In the late 1970 s,Tianjin′s water demand increased rapidly.To alleviate the crisis of water shortage, the State Council of the People′s Republic of China arranged the water transfer project from Luanhe River to Tianjin and identified the proportion of the water distribution in Tianjin and Hebei Provinces in 1983.The completion of the water transfer project of Luanhe River to Tianjin has effectively ensured the safety of Tianjin′s water supply,with an average annual water supply accounting for more than 20%.The water supply safety of Tianjin was further strengthened after the inauguration of the Middle Route of South-to-North Water Diversion Project in 2014.However,with the decline of water resources in the Luanhe River basin, the contradiction between the water supply and demand in major cities in the lower reaches of the Luanhe River has become increasingly prominent,causing problems such as damage to the river′s ecological environment,overexploitation of groundwater,and difficulty in securing water for economic and social development.Based on the follow-up high-quality development of South-to-North Water Diversion Project, optimizing the water distribution scheme of the Luanhe River is very important to ensure the water resources safety of the water receiving areas of the South-to-North Water Transfer Project and the Luanhe River basin. Based on the results of the health state evolution of the water system in the Luanhe River basin,an indicator system was constructed for the health status of the water system.The indicator system was applied to analyze the health status of the water system of Tianjin and Tangshan since 1983.The decline of water resources was analyzed sing data (the water flux into the sea,the amount of groundwater over exploitation,areas of seawater intrusion,ground settlement amount,the demand changes of social economy water),statistical analysis,and other methods. The main results are:①In recent years,there is a significant decline in the water resources. Compared with the first water resource evaluation results, water resources were reduced by 1.7 billion m3 (17.7%),of which the surface water and groundwater resource drop reached by 30.72% and 10.10%,respectively.②Recently,the Luanhe River water ecological environment problem has been more prominent,and the water flux has continued to decrease.In the past 13 years, the average water flux is only 12.7 billion m3,far less than the planning of 4.21 billion m3.③The annually overexploitation of groundwater is more than 510 million m3, which led to cumulative overexploitation of 15 billion m3 in Tangshan,and groundwater depth reached more than 20 m in some areas.The areas of seawater intrusion has been more than 2 000 km2.The largest ground settlement area has reached 2 498.85 mm in the Ninghe area of Tangshan City.④ Last 20 years,two dry years of the Luanhe River basin have caused serious drinking crisis and agricultural reduction.Even with the continuous promotion of water-saving,it is still unable to get rid of the shortage of water resources in Luanhe River.⑤A conception and preliminary implementation was proposed to incorporate the Luanhe River basin into the follow-up planning of South-to-North Water Diversion Project. The main conclusions are:With the completion of the first phase of the Middle Route of the South-to-North Water Diversion Project and the subsequent planning and construction of the Middle East Route,the Luanhe River Diversion Project and the South-to-North Water Diversion Project have established a hydraulic connection with Tianjin.The water receiving areas of South-to-North Water Diversion Projects and Luanhe River basin have water resources synergistic safety guarantee conditions.Therefore,the idea of incorporating the Luanhe River basin into the follow-up of South-to-North Water Diversion Projects was Proposed.This embodiment includes a premise,three supports,and three-step implementation strategies.The implementation strategy of the Luanhe River transfer water distribution was adjusted scheme with the water resources security in Tianjin as the primary premise.The water volume,water resources regulation and storage capacity, and water price are important support. The phase II Project of the East Route of the South-to-North Water Diversion Project is the important node for adjusting the water distribution plan of Luanhe River with three steps as to alleviate the serious water problems to a great extent and maximize the benefits of the South-to-North Water Diversion Project,incorporated the Luanhe River basin into the follow-up high-quality development of the South-to-North Water Diversion Project.
In the late 1970 s,Tianjin′s water demand increased rapidly.To alleviate the crisis of water shortage, the State Council of the People′s Republic of China arranged the water transfer project from Luanhe River to Tianjin and identified the proportion of the water distribution in Tianjin and Hebei Provinces in 1983.The completion of the water transfer project of Luanhe River to Tianjin has effectively ensured the safety of Tianjin′s water supply,with an average annual water supply accounting for more than 20%.The water supply safety of Tianjin was further strengthened after the inauguration of the Middle Route of South-to-North Water Diversion Project in 2014.However,with the decline of water resources in the Luanhe River basin, the contradiction between the water supply and demand in major cities in the lower reaches of the Luanhe River has become increasingly prominent,causing problems such as damage to the river′s ecological environment,overexploitation of groundwater,and difficulty in securing water for economic and social development.Based on the follow-up high-quality development of South-to-North Water Diversion Project, optimizing the water distribution scheme of the Luanhe River is very important to ensure the water resources safety of the water receiving areas of the South-to-North Water Transfer Project and the Luanhe River basin. Based on the results of the health state evolution of the water system in the Luanhe River basin,an indicator system was constructed for the health status of the water system.The indicator system was applied to analyze the health status of the water system of Tianjin and Tangshan since 1983.The decline of water resources was analyzed sing data (the water flux into the sea,the amount of groundwater over exploitation,areas of seawater intrusion,ground settlement amount,the demand changes of social economy water),statistical analysis,and other methods. The main results are:①In recent years,there is a significant decline in the water resources. Compared with the first water resource evaluation results, water resources were reduced by 1.7 billion m3 (17.7%),of which the surface water and groundwater resource drop reached by 30.72% and 10.10%,respectively.②Recently,the Luanhe River water ecological environment problem has been more prominent,and the water flux has continued to decrease.In the past 13 years, the average water flux is only 12.7 billion m3,far less than the planning of 4.21 billion m3.③The annually overexploitation of groundwater is more than 510 million m3, which led to cumulative overexploitation of 15 billion m3 in Tangshan,and groundwater depth reached more than 20 m in some areas.The areas of seawater intrusion has been more than 2 000 km2.The largest ground settlement area has reached 2 498.85 mm in the Ninghe area of Tangshan City.④ Last 20 years,two dry years of the Luanhe River basin have caused serious drinking crisis and agricultural reduction.Even with the continuous promotion of water-saving,it is still unable to get rid of the shortage of water resources in Luanhe River.⑤A conception and preliminary implementation was proposed to incorporate the Luanhe River basin into the follow-up planning of South-to-North Water Diversion Project. The main conclusions are:With the completion of the first phase of the Middle Route of the South-to-North Water Diversion Project and the subsequent planning and construction of the Middle East Route,the Luanhe River Diversion Project and the South-to-North Water Diversion Project have established a hydraulic connection with Tianjin.The water receiving areas of South-to-North Water Diversion Projects and Luanhe River basin have water resources synergistic safety guarantee conditions.Therefore,the idea of incorporating the Luanhe River basin into the follow-up of South-to-North Water Diversion Projects was Proposed.This embodiment includes a premise,three supports,and three-step implementation strategies.The implementation strategy of the Luanhe River transfer water distribution was adjusted scheme with the water resources security in Tianjin as the primary premise.The water volume,water resources regulation and storage capacity, and water price are important support. The phase II Project of the East Route of the South-to-North Water Diversion Project is the important node for adjusting the water distribution plan of Luanhe River with three steps as to alleviate the serious water problems to a great extent and maximize the benefits of the South-to-North Water Diversion Project,incorporated the Luanhe River basin into the follow-up high-quality development of the South-to-North Water Diversion Project.
2022, 20(1):70-78.
Abstract:
The extreme hydrological events such as storms and droughts are sharply increasing,which leads to the coexistence of urban floods and drought.Scientific control of urban rain and flood process is the frontier and hot spot of urban hydrology.Rainwater utilization is one of the important means to alleviate urban waterlogging,and also a key issue to determine the water diversion scale of the subsequent South-to-North Water Diversion Project (SNWDP).It is very necessary to assess the potential of urban rainwater use in the reception basins of SNWDP. The rainwater utilization levels of sponge pilot cities were investigated and analyzed,considering the geographical climate and precipitation characteristics in central-eastern and western China.The two different indicators "Proportion of Tap Water that replaced by rainwater water (PTW)",and "Proportion of Rain Water that used by human beings (PRW)" are used to quantify the rainwater water utilization levels in sponge cities.The conversion formula was put forward to unify the two indicators as PTW.Considering the economic and technical feasibility, the upper, lower threshold, and an average of PTW in the central-eastern and western regions were calculated.The uncertainty of urban rainwater utilization and the guaranteed rate of rainwater supply were quantified based on the hydrological frequency analysis method. The potential rainwater use was calculated based on the datasets of year 2018.The result is 620 million m3, 470 million m3 and 326 million m3 for high,medium and low utilization levels,respectively.Based on the hydrological series from 1970 to 2020,the potential utilization of rainwater resources is 466 million m3,389 million m3 and 282 million m3 for a normal year (P=50%),dry year (P=75%),and extreme dry year (P=95%),respectively.Taking Beijing,Tianjin,Shijiazhuang,Jinan,Taiyuan as sample cities,the guaranteed rate of rainwater utilization was obtained, which were 45.1%,51.0%,41.2%,45.1%,47.1%,respectively, with an average rate of 45.9%.The average rate is far lower than the requirement of the urban water supply guarantee rate. The potential urban rainwater use is quite small compared with the total demand capacity of subsequent projects of SNWDP.Due to the randomness of precipitation,the rainwater use has the characteristics of high uncertainty,low guarantee rate and great interannual variation.The rainwater is suitable as a supplementary water source for the city,instead of serving as a stable water supply.
The extreme hydrological events such as storms and droughts are sharply increasing,which leads to the coexistence of urban floods and drought.Scientific control of urban rain and flood process is the frontier and hot spot of urban hydrology.Rainwater utilization is one of the important means to alleviate urban waterlogging,and also a key issue to determine the water diversion scale of the subsequent South-to-North Water Diversion Project (SNWDP).It is very necessary to assess the potential of urban rainwater use in the reception basins of SNWDP. The rainwater utilization levels of sponge pilot cities were investigated and analyzed,considering the geographical climate and precipitation characteristics in central-eastern and western China.The two different indicators "Proportion of Tap Water that replaced by rainwater water (PTW)",and "Proportion of Rain Water that used by human beings (PRW)" are used to quantify the rainwater water utilization levels in sponge cities.The conversion formula was put forward to unify the two indicators as PTW.Considering the economic and technical feasibility, the upper, lower threshold, and an average of PTW in the central-eastern and western regions were calculated.The uncertainty of urban rainwater utilization and the guaranteed rate of rainwater supply were quantified based on the hydrological frequency analysis method. The potential rainwater use was calculated based on the datasets of year 2018.The result is 620 million m3, 470 million m3 and 326 million m3 for high,medium and low utilization levels,respectively.Based on the hydrological series from 1970 to 2020,the potential utilization of rainwater resources is 466 million m3,389 million m3 and 282 million m3 for a normal year (P=50%),dry year (P=75%),and extreme dry year (P=95%),respectively.Taking Beijing,Tianjin,Shijiazhuang,Jinan,Taiyuan as sample cities,the guaranteed rate of rainwater utilization was obtained, which were 45.1%,51.0%,41.2%,45.1%,47.1%,respectively, with an average rate of 45.9%.The average rate is far lower than the requirement of the urban water supply guarantee rate. The potential urban rainwater use is quite small compared with the total demand capacity of subsequent projects of SNWDP.Due to the randomness of precipitation,the rainwater use has the characteristics of high uncertainty,low guarantee rate and great interannual variation.The rainwater is suitable as a supplementary water source for the city,instead of serving as a stable water supply.
2022, 20(1):79-86.
Abstract:
Ecological regulation is one of the major prevention and control measures,and flow velocity is the key control variable.There is no online reservoir in the main canal,so it is prone to interfere with the normal water delivery downstream,and the hydraulic transition time is long in the process of ecological regulation.Currently,few implementation methods of ecological regulation are put forward. Based on the engineering characteristics of the main canal,the implementation strategy of ecological regulation was proposed by setting up its storage region to isolate the impact of ecological regulation on the downstream.The efficient canal pool operation method was adopted to reduce the repeated adjustment of the storage during ecological regulation.Considering the requirements of safety,speed,and stability,the implementation process and method of ecological regulation were set.The main canal was divided into flow velocity control region,storage regulation region,and normal operation region.The ecological regulation process was divided into the water filling stage and the discharge stage.The implementation steps of ecological regulation were given,including delineating the canal region,calculating the target flow of each gate in the velocity control region and the storage regulation region.Based on a one-dimensional unsteady flow simulation model of the canal,the duration of the flow increase stage and the duration of the flow decrease stage in the water filling stage were calculated.Thereafter,the flow control scheme of the velocity control region in the water filling stage was determined.The flow control scheme was input into the one-dimensional unsteady flow simulation model to judge the water level peak of each canal pool,if the safety requirement canal pool in the regulation region would be extended to downstream.After the duration of the discharge stage and the change value of the flow control of each gate in the discharge stage were calculated,and the discharge flow control scheme of the discharge stage was determined.The water filling flow control scheme and discharge flow control scheme meeting the conditions were taken as the gate group control scheme. Taking the operation of the main canal in March 2018 as a case study,a one-dimensional unsteady flow numerical simulation of algae ecological regulation was carried out.The results showed that the ecological regulation of 15 canal pools in the upper reaches of the main canal could be implemented within 3.5 days,and the flow velocity increased from about 0.4 m/s to about 0.7 m/s for more than 2 h.The water level changed smoothly and met the safety threshold requirements,and the flow in the normal operation region was not affected evidently. The proposed ecological regulation strategy and implementation method can achieve the velocity control goal along with ensuring the operation safety of the interference propagation to the downstream and reducing the hydraulic transition process.It can be used for not only algae control but also sediment deposition removal,aquatic biological attachment removal,and other velocity control scenarios.
Ecological regulation is one of the major prevention and control measures,and flow velocity is the key control variable.There is no online reservoir in the main canal,so it is prone to interfere with the normal water delivery downstream,and the hydraulic transition time is long in the process of ecological regulation.Currently,few implementation methods of ecological regulation are put forward. Based on the engineering characteristics of the main canal,the implementation strategy of ecological regulation was proposed by setting up its storage region to isolate the impact of ecological regulation on the downstream.The efficient canal pool operation method was adopted to reduce the repeated adjustment of the storage during ecological regulation.Considering the requirements of safety,speed,and stability,the implementation process and method of ecological regulation were set.The main canal was divided into flow velocity control region,storage regulation region,and normal operation region.The ecological regulation process was divided into the water filling stage and the discharge stage.The implementation steps of ecological regulation were given,including delineating the canal region,calculating the target flow of each gate in the velocity control region and the storage regulation region.Based on a one-dimensional unsteady flow simulation model of the canal,the duration of the flow increase stage and the duration of the flow decrease stage in the water filling stage were calculated.Thereafter,the flow control scheme of the velocity control region in the water filling stage was determined.The flow control scheme was input into the one-dimensional unsteady flow simulation model to judge the water level peak of each canal pool,if the safety requirement canal pool in the regulation region would be extended to downstream.After the duration of the discharge stage and the change value of the flow control of each gate in the discharge stage were calculated,and the discharge flow control scheme of the discharge stage was determined.The water filling flow control scheme and discharge flow control scheme meeting the conditions were taken as the gate group control scheme. Taking the operation of the main canal in March 2018 as a case study,a one-dimensional unsteady flow numerical simulation of algae ecological regulation was carried out.The results showed that the ecological regulation of 15 canal pools in the upper reaches of the main canal could be implemented within 3.5 days,and the flow velocity increased from about 0.4 m/s to about 0.7 m/s for more than 2 h.The water level changed smoothly and met the safety threshold requirements,and the flow in the normal operation region was not affected evidently. The proposed ecological regulation strategy and implementation method can achieve the velocity control goal along with ensuring the operation safety of the interference propagation to the downstream and reducing the hydraulic transition process.It can be used for not only algae control but also sediment deposition removal,aquatic biological attachment removal,and other velocity control scenarios.
2022, 20(1):87-92.
Abstract:
The South-to-North Water Diversion Project is China′s first cross-basin water diversion project for the returning water to the river for improving the regional water ecology.The project not only alleviated the water shortage in North China and eastern coastal cities,increased the ecological water volume of rivers and lakes,but also restrained local groundwater overexploitation.Affected by the management system,operation mechanism,dispatching mode,price and other factors,the water transferred from some water receiving areas has not been fully utilized,which affects the normal play of the overall benefits of the South-to-North Water Diversion.Aiming at the problem of insufficient utilization of water diversion project,the mode and path to promote the effective utilization of water diversion is discussed.The problem of insufficient water diversion is due to the high water price of the water diversion project,the lagging of supporting projects,as well as the dispersion of some water supply enterprises in the intake area,and the lack of integrated water management. Dongying City is the intake area of the South-to-North Water Diversion Project,and to discuss innovation and design of water rights conversion mode is significant for this project.According to the economic and social development and the distribution of water resources allocation,the mode of unified allocation and comprehensive pricing,directional supply and independent accounting,water rights conversion and market bidding is put forward.Focusing on the mode of water rights conversion,the mechanism of incremental water rights utilization is initially constructed,including the definition of stakeholders,information management,transaction pricing,transaction coordination and contract management.The water rights trading platform is designed.The definition of the nature of the platform,the source of water rights,the responsibilities of stakeholders,the access requirements and transfer period is also discussed. Incremental water rights use attempts to break through the barriers in the process of utilization and establish a connection between the supply and demand sides,with the goal being market demand-oriented.The allocation of water resources is optimized and conservation and intensive use of regional water resources are promoted through the combination of government administrative regulation and market economic regulation.This process will alleviate the situation of insufficient water utilization from the eastern route of the South-to-North Water Diversion Project in the south of the Yellow River in Dongying City and water shortage constraints in the industrial development in the north of the Yellow River.It is of great significance to promote regional ecological protection and high-quality development. In the process of building a water rights trading platform and promoting the use of water rights trading,relevant work can be promoted through a gradual model.First,it can rely on existing institutions to integrate and gradually improve the water rights transaction management institution.Second,small-scale water rights conversion projects can be selected to carry out typical demonstrations,and the demonstration will be fully promoted when they are mature.Finally,in the actual operation and management process,there are still problems such as the difference between the water quality of the transferred water source and the existing water source,and the cost accounting and apportionment of the transfer process,which need to be further refined and improved in the following work.
The South-to-North Water Diversion Project is China′s first cross-basin water diversion project for the returning water to the river for improving the regional water ecology.The project not only alleviated the water shortage in North China and eastern coastal cities,increased the ecological water volume of rivers and lakes,but also restrained local groundwater overexploitation.Affected by the management system,operation mechanism,dispatching mode,price and other factors,the water transferred from some water receiving areas has not been fully utilized,which affects the normal play of the overall benefits of the South-to-North Water Diversion.Aiming at the problem of insufficient utilization of water diversion project,the mode and path to promote the effective utilization of water diversion is discussed.The problem of insufficient water diversion is due to the high water price of the water diversion project,the lagging of supporting projects,as well as the dispersion of some water supply enterprises in the intake area,and the lack of integrated water management. Dongying City is the intake area of the South-to-North Water Diversion Project,and to discuss innovation and design of water rights conversion mode is significant for this project.According to the economic and social development and the distribution of water resources allocation,the mode of unified allocation and comprehensive pricing,directional supply and independent accounting,water rights conversion and market bidding is put forward.Focusing on the mode of water rights conversion,the mechanism of incremental water rights utilization is initially constructed,including the definition of stakeholders,information management,transaction pricing,transaction coordination and contract management.The water rights trading platform is designed.The definition of the nature of the platform,the source of water rights,the responsibilities of stakeholders,the access requirements and transfer period is also discussed. Incremental water rights use attempts to break through the barriers in the process of utilization and establish a connection between the supply and demand sides,with the goal being market demand-oriented.The allocation of water resources is optimized and conservation and intensive use of regional water resources are promoted through the combination of government administrative regulation and market economic regulation.This process will alleviate the situation of insufficient water utilization from the eastern route of the South-to-North Water Diversion Project in the south of the Yellow River in Dongying City and water shortage constraints in the industrial development in the north of the Yellow River.It is of great significance to promote regional ecological protection and high-quality development. In the process of building a water rights trading platform and promoting the use of water rights trading,relevant work can be promoted through a gradual model.First,it can rely on existing institutions to integrate and gradually improve the water rights transaction management institution.Second,small-scale water rights conversion projects can be selected to carry out typical demonstrations,and the demonstration will be fully promoted when they are mature.Finally,in the actual operation and management process,there are still problems such as the difference between the water quality of the transferred water source and the existing water source,and the cost accounting and apportionment of the transfer process,which need to be further refined and improved in the following work.
2022, 20(1):93-101.
Abstract:
Since the Middle Route of the South-to-North Water Diversion Project began to supply water in 2014,it has transferred more than 40 billion cubic meters of water and directly benefited 79 million people.However,how to quantitatively evaluate the specific effect of the project and what level the relationship between water resources and economic and social development in the water receiving areas is closely concerned by the national water project management department,the people in the receiving areas.There is need to understood the optimization of water resource allocation and accurate dispatching of the project. Water resources were looked at as a key factor affecting economic and social development.The evaluation model of the harmonious development of water resources and economic society in the water receiving area was constructed based on humanwater harmony.Six key time nodes in the typical water receiving area in Henan Province such as before the construction of the project (1999,2000),during the construction period (2003),under construction (2008) and after the water supply of the project (2014,2018) are selected to conduct a comparative study on the harmony between water resources and economy and society in the water receiving areas. The harmony degree of typical water receiving areas in Henan Province can be roughly divided into three stages from the time dimension.The first stage was before the construction of the project(1999-2003),the overall degree was below 0.5,the value was low but showed an upward trend.The second stage was after the commencement of the project (2003-2008),the harmony degree in some places reached 0.6,but the overall degree of harmony has not increased significantly.The third stage was after the water supply of the project (2014-2018),the degree of harmony in each receiving area began to rise again,maximum degree reached 0.7.From the spatial dimension,the harmony degree of Nanyang City and Xuchang City,which were closed to the water source area,basically increased steadily,while that of Zhengzhou City and Pingdingshan City increased and then decreased. In terms of a time dimension,each index showed an inflection point in the year of project commencement 2003.The increase from 1999 to 2003 is due to the rapid development,and potential economic growth of Henan Province.Health,development,and coordination have increased steadily.The health degree decreased from 2003 to 2008.On the one hand,due to the rapid economic development and less attention to environmental protection,the health degree decreased,the total amount of water resources decreased,the water production coefficient decreased,and the overall harmony degree also decreased.From the perspective of spatial dimension,the degree of harmony of Zhengzhou,Xinxiang,Jiaozuo and Xuchang increased,but the degree of harmony of Pingdingshan and Nanyang decreased.The financial crisis in 2007 and drought in different degrees may be the reason behind this decrease.After 2010,the importance of harmonious development started to develop and began to reduce water pollution and the total amount of water resources and water production coefficient rebounded.The degree of harmony generally showed fluctuated upward trend.In 1999,the degree of harmony in most water receiving areas was very low and basically in an inharmonious state.It has been rising from 1999 to 2003,the harmony degree of Pingdingshan and Nanyang reached 0.5 for the first time.However,the upward trend in 2008 was not obvious,and there was a slight decline in some regions.It began to rise steadily from 2008 to 2018.The reason is that the water supply of the Middle Route of South-to-North Water Diversion Project in 2014 has alleviated some problems of serious shortage of water resources to a certain extent,such as the restrictions of water shortage on economic development and water pollution on the environment.Moreover,the operation of the project has also brought many opportunities for Henan Province and promoted the vigorous development of the economy,but the degree of harmony between water resources and economy and society is still low.It is suggested that the available water quantity of South-to-North Water Diversion Project in Henan Province should be coordinated at the provincial level,the water right trading mechanism should be established,the management of high water consumption industries should be strengthened,and the utilization efficiency of water resources should be improved.
Since the Middle Route of the South-to-North Water Diversion Project began to supply water in 2014,it has transferred more than 40 billion cubic meters of water and directly benefited 79 million people.However,how to quantitatively evaluate the specific effect of the project and what level the relationship between water resources and economic and social development in the water receiving areas is closely concerned by the national water project management department,the people in the receiving areas.There is need to understood the optimization of water resource allocation and accurate dispatching of the project. Water resources were looked at as a key factor affecting economic and social development.The evaluation model of the harmonious development of water resources and economic society in the water receiving area was constructed based on humanwater harmony.Six key time nodes in the typical water receiving area in Henan Province such as before the construction of the project (1999,2000),during the construction period (2003),under construction (2008) and after the water supply of the project (2014,2018) are selected to conduct a comparative study on the harmony between water resources and economy and society in the water receiving areas. The harmony degree of typical water receiving areas in Henan Province can be roughly divided into three stages from the time dimension.The first stage was before the construction of the project(1999-2003),the overall degree was below 0.5,the value was low but showed an upward trend.The second stage was after the commencement of the project (2003-2008),the harmony degree in some places reached 0.6,but the overall degree of harmony has not increased significantly.The third stage was after the water supply of the project (2014-2018),the degree of harmony in each receiving area began to rise again,maximum degree reached 0.7.From the spatial dimension,the harmony degree of Nanyang City and Xuchang City,which were closed to the water source area,basically increased steadily,while that of Zhengzhou City and Pingdingshan City increased and then decreased. In terms of a time dimension,each index showed an inflection point in the year of project commencement 2003.The increase from 1999 to 2003 is due to the rapid development,and potential economic growth of Henan Province.Health,development,and coordination have increased steadily.The health degree decreased from 2003 to 2008.On the one hand,due to the rapid economic development and less attention to environmental protection,the health degree decreased,the total amount of water resources decreased,the water production coefficient decreased,and the overall harmony degree also decreased.From the perspective of spatial dimension,the degree of harmony of Zhengzhou,Xinxiang,Jiaozuo and Xuchang increased,but the degree of harmony of Pingdingshan and Nanyang decreased.The financial crisis in 2007 and drought in different degrees may be the reason behind this decrease.After 2010,the importance of harmonious development started to develop and began to reduce water pollution and the total amount of water resources and water production coefficient rebounded.The degree of harmony generally showed fluctuated upward trend.In 1999,the degree of harmony in most water receiving areas was very low and basically in an inharmonious state.It has been rising from 1999 to 2003,the harmony degree of Pingdingshan and Nanyang reached 0.5 for the first time.However,the upward trend in 2008 was not obvious,and there was a slight decline in some regions.It began to rise steadily from 2008 to 2018.The reason is that the water supply of the Middle Route of South-to-North Water Diversion Project in 2014 has alleviated some problems of serious shortage of water resources to a certain extent,such as the restrictions of water shortage on economic development and water pollution on the environment.Moreover,the operation of the project has also brought many opportunities for Henan Province and promoted the vigorous development of the economy,but the degree of harmony between water resources and economy and society is still low.It is suggested that the available water quantity of South-to-North Water Diversion Project in Henan Province should be coordinated at the provincial level,the water right trading mechanism should be established,the management of high water consumption industries should be strengthened,and the utilization efficiency of water resources should be improved.
2022, 20(1):102-109.
Abstract:
The sixth assessment report of the Intergovernmental Panel on Climate Change shows that global surface temperature has increased,causing more frequent and intensive extreme climate events such as floods and drought.The total annual flood losses are estimated to be 100 billion dollars worldwide and cause serious casualties.For example,3 563 floods happened over the past thirty years from 1980 to 2010 in 37 European counties.Four out of the top ten natural disasters were related to flooding in 2020 in China,causing 247 deaths and 2 255 billion direct financial losses.Urbanization plays a magnifying effect on the flood disaster.The urban heat and rain island effects make more precipitation extremes in urban areas.However,accurate precipitation prediction at the city scale is still a scientific problem.How to deal with urban rainstorm and flood disasters is a new challenge of global flood management. Under the influence of climate change and urbanization,urban rainstorm and flood disasters occur more frequently and extensively,causing serious casualties and economic losses.The problem of an urban rainstorm and flood control and disasters reduction has been paid wide attention by the government and scholars.To reduce the effects of the urban rainstorm and flood disasters,both adaptive engineering and nonengineering strategies can be considered.However,engineering strategies such as sponge city generally need tremendous investments for both construction and maintenance.The non-engineering strategies are focused on.However,the problems of forecast and prediction,monitoring and early warning, multi-department cooperative management for an urban rainstorm and flood disasters still need to be solved.Based on the concept of disaster prevention,mitigation,and relief,taking disaster prevention,a five-pre response mechanism for urban rainstorm and flood disasters is proposed,which integrates scenario projection,forecast and prediction,monitoring and early warning,emergency plan,and flood control rehearsal. The results show that the five-pre response mechanism for the urban rainstorm and flood disasters realizes the long term projection,the medium and short-term forecast and prediction,the near-real-time monitoring and early warning, the real-time emergency plan, and the urban rainstorm and flood disasters control and rehearsal before the disasters,which can provide a set of non-engineering measures capable of actual operation for the urban rainstorm and flood disaster response.The five-pre response mechanism for the urban rainstorm and flood disasters can be implemented as follows:Urban rainstorm and flood disasters scenario projection based on a climate model;urban rainstorm and flood disaster forecast and prediction based on coupling meteorology and hydrology;urban rainstorm and flood disasters monitoring and early warning based on multi-source information fusion;urban rainstorm and flood disasters emergency plan based on meta-synthesis platform;urban rainstorm and flood disasters control and rehearsal based on digital twin. The key technologies and supporting platforms of the five-pre response mechanism for the urban rainstorm and flood disasters are further expounded,which provide scientific support for urban rainstorm and flood disasters response.They include urban rainstorm and flood models,earth system models, rolling climate forecast technology,numerical weather prediction technology,three-dimensional digital sand table,metasynthesis platform,and digital twin city.The five-pre response mechanism provides a new idea to systematically resolve urban rainstorm and flood disasters.However,some of the technologies such as rainstorm projection and forecast at the urban scale,rainstorm accurate prediction are still scientific or technical problems that are unresolved,which need further investigation using interdisciplinary theories and technologies.
The sixth assessment report of the Intergovernmental Panel on Climate Change shows that global surface temperature has increased,causing more frequent and intensive extreme climate events such as floods and drought.The total annual flood losses are estimated to be 100 billion dollars worldwide and cause serious casualties.For example,3 563 floods happened over the past thirty years from 1980 to 2010 in 37 European counties.Four out of the top ten natural disasters were related to flooding in 2020 in China,causing 247 deaths and 2 255 billion direct financial losses.Urbanization plays a magnifying effect on the flood disaster.The urban heat and rain island effects make more precipitation extremes in urban areas.However,accurate precipitation prediction at the city scale is still a scientific problem.How to deal with urban rainstorm and flood disasters is a new challenge of global flood management. Under the influence of climate change and urbanization,urban rainstorm and flood disasters occur more frequently and extensively,causing serious casualties and economic losses.The problem of an urban rainstorm and flood control and disasters reduction has been paid wide attention by the government and scholars.To reduce the effects of the urban rainstorm and flood disasters,both adaptive engineering and nonengineering strategies can be considered.However,engineering strategies such as sponge city generally need tremendous investments for both construction and maintenance.The non-engineering strategies are focused on.However,the problems of forecast and prediction,monitoring and early warning, multi-department cooperative management for an urban rainstorm and flood disasters still need to be solved.Based on the concept of disaster prevention,mitigation,and relief,taking disaster prevention,a five-pre response mechanism for urban rainstorm and flood disasters is proposed,which integrates scenario projection,forecast and prediction,monitoring and early warning,emergency plan,and flood control rehearsal. The results show that the five-pre response mechanism for the urban rainstorm and flood disasters realizes the long term projection,the medium and short-term forecast and prediction,the near-real-time monitoring and early warning, the real-time emergency plan, and the urban rainstorm and flood disasters control and rehearsal before the disasters,which can provide a set of non-engineering measures capable of actual operation for the urban rainstorm and flood disaster response.The five-pre response mechanism for the urban rainstorm and flood disasters can be implemented as follows:Urban rainstorm and flood disasters scenario projection based on a climate model;urban rainstorm and flood disaster forecast and prediction based on coupling meteorology and hydrology;urban rainstorm and flood disasters monitoring and early warning based on multi-source information fusion;urban rainstorm and flood disasters emergency plan based on meta-synthesis platform;urban rainstorm and flood disasters control and rehearsal based on digital twin. The key technologies and supporting platforms of the five-pre response mechanism for the urban rainstorm and flood disasters are further expounded,which provide scientific support for urban rainstorm and flood disasters response.They include urban rainstorm and flood models,earth system models, rolling climate forecast technology,numerical weather prediction technology,three-dimensional digital sand table,metasynthesis platform,and digital twin city.The five-pre response mechanism provides a new idea to systematically resolve urban rainstorm and flood disasters.However,some of the technologies such as rainstorm projection and forecast at the urban scale,rainstorm accurate prediction are still scientific or technical problems that are unresolved,which need further investigation using interdisciplinary theories and technologies.
2022, 20(1):110-121.
Abstract:
With the acceleration of urbanization,the underlying surface of a city has undergone tremendous changes.The area of bare vegetation has been reduced,and the area of construction roads has increased.This has significantly increased the impermeability of urban areas,reduced the amount of rainwater infiltration,and condensed the drainage system.Surface rain can not be discharged quickly,and urban flood disasters occur frequently.To change the urban waterlogging problem ,the improvement and transformation of urban rainwater pipe network systems are the key points.However,most cities in China have low design standards for rainwater pipe network systems and can not cope with extreme rainstorms with high return periods.Since the 1980s,with the development of remote sensing technology and geographic information system and its wide application in hydrology,significant progress has been made in urban hydrology research.Many urban hydrological models have been developed and applied in urban hydrology.The model performs urban waterlogging simulation and rainwater pipe network system analysis can provide solutions for improving urban waterlogging problems. SWMM (storm water management model) is a dynamic precipitation-runoff simulation model,which is mainly used to simulate a single precipitation event or long-term water quantity and water quality simulation in a city.Its runoff module part comprehensively handles precipitation,runoff,and pollution load in each sub-basin.The confluence module part transmits water volume through pipe networks,channels,water storage and treatment facilities,water pumps,and regulating gates.The model can track and simulate the water quality and quantity of runoff produced by each sub-basin at any time with different time steps,as well as the flow,depth and quality of water in each pipeline and river.Likewise,the SCS model is developed by the Bureau of Water and Soil Conservation belonging to the United States Department of Agriculture in 1954.It is widely used in watershed hydrological simulations.The runoff curve number method (SCS-CN) has a simple calculation process,few parameters required,easy access to data,and consideration of the characteristics of the underlying surface of the region. The surface runoff continuity errors of the simulation results obtained by inputting three spots of rain with different recurrence periods are all 0,and the continuity errors of flow calculation are -0.43%,-0.24%,and -0.18%,respectively.Using the comprehensive runoff coefficient method,the comprehensive runoff coefficients of the measured rainfall data are 0.658,0.667,and 0.682 in sequence.The pipe network is analyzed:when the rain return period is 1 a,the full pipe rate of the pipe section is 4.4%,and the pipe section overload rate is 4.4%.When the rain return period is 2 a,the full pipe section rate is 24.53%,and the pipe section overload rate is 24.53%.The return period of rainfall increased to 5 years,the full pipe section rate was 33.96%,and the pipe section overload rate was 32.08%.The main influencing factors of pipeline overload are the overload of upstream and downstream pipelines,the accumulation of water at both ends,the impermeability of the surrounding catchment area and its total area.The nodes are analyzed: when the rainfall return period is 1 a,8 nodes generate water,when the rainfall return period is 2 a,37 nodes generate water,and when the rainfall return period is 5 a,60 nodes generate water.The main influencing factors of node stagnant water are the impermeability of the catchment area,the CN value,the total area,and the density of the city and the pipeline network. The model can simulate the urban rainstorm and waterlogging in Zhengzhou Hightech Zone,but the rainwater pipe network system in the high.tech zone can not well cope with the heavy rain in the design return period in the drainage code of Zhengzhou City.The overload pipe section and stagnant water of the drainage pipe network of Zhengzhou High.tech Zone have different nodes,but the two have a close positive correlation.The nodes at both ends of the overloaded pipe section are more prone to overflow,thus forming four obvious flood.prone areas.
With the acceleration of urbanization,the underlying surface of a city has undergone tremendous changes.The area of bare vegetation has been reduced,and the area of construction roads has increased.This has significantly increased the impermeability of urban areas,reduced the amount of rainwater infiltration,and condensed the drainage system.Surface rain can not be discharged quickly,and urban flood disasters occur frequently.To change the urban waterlogging problem ,the improvement and transformation of urban rainwater pipe network systems are the key points.However,most cities in China have low design standards for rainwater pipe network systems and can not cope with extreme rainstorms with high return periods.Since the 1980s,with the development of remote sensing technology and geographic information system and its wide application in hydrology,significant progress has been made in urban hydrology research.Many urban hydrological models have been developed and applied in urban hydrology.The model performs urban waterlogging simulation and rainwater pipe network system analysis can provide solutions for improving urban waterlogging problems. SWMM (storm water management model) is a dynamic precipitation-runoff simulation model,which is mainly used to simulate a single precipitation event or long-term water quantity and water quality simulation in a city.Its runoff module part comprehensively handles precipitation,runoff,and pollution load in each sub-basin.The confluence module part transmits water volume through pipe networks,channels,water storage and treatment facilities,water pumps,and regulating gates.The model can track and simulate the water quality and quantity of runoff produced by each sub-basin at any time with different time steps,as well as the flow,depth and quality of water in each pipeline and river.Likewise,the SCS model is developed by the Bureau of Water and Soil Conservation belonging to the United States Department of Agriculture in 1954.It is widely used in watershed hydrological simulations.The runoff curve number method (SCS-CN) has a simple calculation process,few parameters required,easy access to data,and consideration of the characteristics of the underlying surface of the region. The surface runoff continuity errors of the simulation results obtained by inputting three spots of rain with different recurrence periods are all 0,and the continuity errors of flow calculation are -0.43%,-0.24%,and -0.18%,respectively.Using the comprehensive runoff coefficient method,the comprehensive runoff coefficients of the measured rainfall data are 0.658,0.667,and 0.682 in sequence.The pipe network is analyzed:when the rain return period is 1 a,the full pipe rate of the pipe section is 4.4%,and the pipe section overload rate is 4.4%.When the rain return period is 2 a,the full pipe section rate is 24.53%,and the pipe section overload rate is 24.53%.The return period of rainfall increased to 5 years,the full pipe section rate was 33.96%,and the pipe section overload rate was 32.08%.The main influencing factors of pipeline overload are the overload of upstream and downstream pipelines,the accumulation of water at both ends,the impermeability of the surrounding catchment area and its total area.The nodes are analyzed: when the rainfall return period is 1 a,8 nodes generate water,when the rainfall return period is 2 a,37 nodes generate water,and when the rainfall return period is 5 a,60 nodes generate water.The main influencing factors of node stagnant water are the impermeability of the catchment area,the CN value,the total area,and the density of the city and the pipeline network. The model can simulate the urban rainstorm and waterlogging in Zhengzhou Hightech Zone,but the rainwater pipe network system in the high.tech zone can not well cope with the heavy rain in the design return period in the drainage code of Zhengzhou City.The overload pipe section and stagnant water of the drainage pipe network of Zhengzhou High.tech Zone have different nodes,but the two have a close positive correlation.The nodes at both ends of the overloaded pipe section are more prone to overflow,thus forming four obvious flood.prone areas.
2022, 20(1):122-130.
Abstract:
The special topography and soil characteristics of the hilly slopes in southern China make the hydrological process that drives the nitrateN transport showing highly non-linear.Thus,the study of slope nitrate-N loss process varying with time associated with nonlinear rainfall-runoff is very important.The rainfall and antecedent soil moisture are the significant factors influencing the natural runoff process and non-point source pollution loss.Most scholars consider the pollutant generation coefficient as a constant for the sake of simplicity,and it lacks the detailed quantitative description and mechanism study. An artificial simulation rainfall-runoff-pollutant generation experiment equipment close to natural rainfall with a high degree of automation observation was developed.The designed contrast control experimental method was employed to study the runoff generation and nitrateN generation process near the surface soil under different rainfall intensity and antecedent soil moisture.The mathematical derivation method was used to discuss the relationship between the nitrate-N generation coefficient,runoff,and soil moisture near the surface soil. The runoff generation escalated with time in a power function form initially and then keeps stability later.The larger the rainfall intensity and the higher the antecedent soil moisture,the runoff-yielding time was faster,the runoff generation and the cumulative runoff generation were larger,the time for the runoff stabilization was shorter,and the runoff stabilization value was higher.The nitrate-N load and cumulative nitrateN load were higher at the beginning of the rainfall.It showed decreasing trend in a power function form,and finally became stable along with the runoff.With the increase of the rainfall intensity and antecedent soil moisture content,the nitrate-N load and cumulative nitrateN load increased,and the time for the nitrate-N load stabilization was shorter. The two parameters relationship formula between the nitrate-N generation coefficient and the soil moisture driven by the nonlinear rainfall-runoff could better describe the nitrate-N generation process near the surface soil.The rainfall-runoff plays a decisive role for the nitrate-N generation coefficient,and it has an exponential function relationship with the soil moisture under the nonlinear rainfall-runoff condition.The discussed relationship between the rainfall-runoff,the nitrate-N generation coefficient,and the soil moisture could provide a certain reference value for simulating the nitrate-N generation coefficient process near the surface soil driven by the nonlinear rainfall-runoff with high time resolution.
The special topography and soil characteristics of the hilly slopes in southern China make the hydrological process that drives the nitrateN transport showing highly non-linear.Thus,the study of slope nitrate-N loss process varying with time associated with nonlinear rainfall-runoff is very important.The rainfall and antecedent soil moisture are the significant factors influencing the natural runoff process and non-point source pollution loss.Most scholars consider the pollutant generation coefficient as a constant for the sake of simplicity,and it lacks the detailed quantitative description and mechanism study. An artificial simulation rainfall-runoff-pollutant generation experiment equipment close to natural rainfall with a high degree of automation observation was developed.The designed contrast control experimental method was employed to study the runoff generation and nitrateN generation process near the surface soil under different rainfall intensity and antecedent soil moisture.The mathematical derivation method was used to discuss the relationship between the nitrate-N generation coefficient,runoff,and soil moisture near the surface soil. The runoff generation escalated with time in a power function form initially and then keeps stability later.The larger the rainfall intensity and the higher the antecedent soil moisture,the runoff-yielding time was faster,the runoff generation and the cumulative runoff generation were larger,the time for the runoff stabilization was shorter,and the runoff stabilization value was higher.The nitrate-N load and cumulative nitrateN load were higher at the beginning of the rainfall.It showed decreasing trend in a power function form,and finally became stable along with the runoff.With the increase of the rainfall intensity and antecedent soil moisture content,the nitrate-N load and cumulative nitrateN load increased,and the time for the nitrate-N load stabilization was shorter. The two parameters relationship formula between the nitrate-N generation coefficient and the soil moisture driven by the nonlinear rainfall-runoff could better describe the nitrate-N generation process near the surface soil.The rainfall-runoff plays a decisive role for the nitrate-N generation coefficient,and it has an exponential function relationship with the soil moisture under the nonlinear rainfall-runoff condition.The discussed relationship between the rainfall-runoff,the nitrate-N generation coefficient,and the soil moisture could provide a certain reference value for simulating the nitrate-N generation coefficient process near the surface soil driven by the nonlinear rainfall-runoff with high time resolution.
2022, 20(1):131-140.
Abstract:
To analyze the impact of surface runoff velocity on urban flood inundation,the dynamic coupled model is applied to generate the flood inundation map of a typical area in Dalian.The characteristics of flood inundation are compared and analyzed under several combinations between surface runoff velocities and return periods of design rainfall.A series of surface runoff velocity schemes are set up to simulate the dynamic process of flood inundation given different return periods of design rainfall,and also to quantitatively analyze the influence of surface runoff velocity on flood inundation,which provides support for urban flood analysis as well as flood disaster prevention and control. The one-dimensional pipe network model consists of 181 manholes,4 outlets,193 drainage pipelines and 181 sub-catchments.The largest and minimum area of sub-catchments is 2.29×10.4 m2 and 116 m2,respectively.The two-dimensional terrain model is divided into 4 032 rectangular grids with a grid size of 15 m×15 m.The surface runoff velocity is set to be 0.02 m/s,0.05 m/s,0.1 m/s and 0.3 m/s.40 simulation schemes are generated in combination with ten types of rainfall return periods.The pipeline pressure state is evaluated by the pipe filling,and the water accumulated over the study area is evaluated by manhole overflow.The risk of flood inundation is divided into three levels,namely,high-,medium-,and low-risk areas. The results show that the drainage load of the pipeline becomes smaller and the qualified rate of the pipeline becomes higher with the decrease of surface runoff velocity under the two-hourly design rainfall.And the qualified length and rate can be increased by 4.7 km and 48.05% with the decrease of surface runoff velocity.Moreover,surface runoff velocity has a significant influence on the volume of accumulated water.When the surface runoff velocity decreases,the peak value of accumulated water volume becomes smaller,and the delay of peak time is longer.The reduction effect of accumulated water is weakened with the increase of rainfall return period.With the decrease of surface runoff velocity,the peak value of total accumulated water can be reduced by 2 750 m3 at most,and the peak time can be delayed by 56 min at most.Meanwhile,under the 24-hourly design rainfall,the area of low-risk and high-risk areas decreases largely as the surface runoff velocity decreases.With the decrease of surface runoff velocity,the areas of low-risk and high-risk areas can be reduced by 1.64×10.4 m2 and 8.37×10.4 m2,respectively,while the area of a medium-risk area changes irregularly. The main conclusions are as follows: The surface runoff velocity has a significant impact on urban flood inundation.It affects the degree of urban flood inundation by changing the drainage load of the pipeline,the amount of ponding,and the area of the risk area.Overall,the decrease of surface runoff velocity,the harm of urban flood inundation is smaller.The relevant conclusions can provide decision-making references for relevant workers.
To analyze the impact of surface runoff velocity on urban flood inundation,the dynamic coupled model is applied to generate the flood inundation map of a typical area in Dalian.The characteristics of flood inundation are compared and analyzed under several combinations between surface runoff velocities and return periods of design rainfall.A series of surface runoff velocity schemes are set up to simulate the dynamic process of flood inundation given different return periods of design rainfall,and also to quantitatively analyze the influence of surface runoff velocity on flood inundation,which provides support for urban flood analysis as well as flood disaster prevention and control. The one-dimensional pipe network model consists of 181 manholes,4 outlets,193 drainage pipelines and 181 sub-catchments.The largest and minimum area of sub-catchments is 2.29×10.4 m2 and 116 m2,respectively.The two-dimensional terrain model is divided into 4 032 rectangular grids with a grid size of 15 m×15 m.The surface runoff velocity is set to be 0.02 m/s,0.05 m/s,0.1 m/s and 0.3 m/s.40 simulation schemes are generated in combination with ten types of rainfall return periods.The pipeline pressure state is evaluated by the pipe filling,and the water accumulated over the study area is evaluated by manhole overflow.The risk of flood inundation is divided into three levels,namely,high-,medium-,and low-risk areas. The results show that the drainage load of the pipeline becomes smaller and the qualified rate of the pipeline becomes higher with the decrease of surface runoff velocity under the two-hourly design rainfall.And the qualified length and rate can be increased by 4.7 km and 48.05% with the decrease of surface runoff velocity.Moreover,surface runoff velocity has a significant influence on the volume of accumulated water.When the surface runoff velocity decreases,the peak value of accumulated water volume becomes smaller,and the delay of peak time is longer.The reduction effect of accumulated water is weakened with the increase of rainfall return period.With the decrease of surface runoff velocity,the peak value of total accumulated water can be reduced by 2 750 m3 at most,and the peak time can be delayed by 56 min at most.Meanwhile,under the 24-hourly design rainfall,the area of low-risk and high-risk areas decreases largely as the surface runoff velocity decreases.With the decrease of surface runoff velocity,the areas of low-risk and high-risk areas can be reduced by 1.64×10.4 m2 and 8.37×10.4 m2,respectively,while the area of a medium-risk area changes irregularly. The main conclusions are as follows: The surface runoff velocity has a significant impact on urban flood inundation.It affects the degree of urban flood inundation by changing the drainage load of the pipeline,the amount of ponding,and the area of the risk area.Overall,the decrease of surface runoff velocity,the harm of urban flood inundation is smaller.The relevant conclusions can provide decision-making references for relevant workers.
2022, 20(1):141-151.
Abstract:
The global warming trend has intensified,increasing the frequency of heavy rain disasters in China,making the mountain watershed easy to produce flash floods.Rain pattern was one of the influencing factors of mountain torrent disaster.Applying the designed rainstorm pattern to watersheds with different vegetation coverage rates in mountainous areas may help to analyze the impact of design rainstorm patterns in different return periods in watersheds.Thus it is important to reveal the response law of different vegetation coverage basins in mountainous areas to different rainstorms,and provide technical support for a more reasonable analysis of mountain rainstorms and floods. The Dayi,Guankou,and Hanwangchang watersheds in Sichuan Province were taken as the study area,and the spatio-temporal variable source mixed runoff generation model was used.The runoff coefficient,flood peak modulus,average runoff coefficient,and average flood peak modulus were used to design rainstorms for different return periods.Analysis of the hydrological process was formed by precipitation under different vegetation coverage in the watershed under different vegetation conditions. In the three small watersheds of Sichuan Province simulated by the spatio-temporal variable source mixed runoff generation model,the simulation accuracy evaluation index values were within the allowable range,indicating that the spatio-temporal variable source mixed runoff generation model was suitable for flood process simulation in small mountain basins.The runoff coefficient and flood peak modulus showed different characteristics under different return periods and different design rainstorm conditions.Under different return period conditions,the rainfall patterns in the basin show a decreasing trend from the front type,the middle type to the rear type,and the flood peak modulus is increasing.Under different rainstorm designs conditions,the runoff coefficient first increases and then decreases slightly and then tends to a stable state under increase of the return period,and the flood peak modulus increases with the increase of the return period. The watersheds with different vegetation coverage respond differently to the designed rainstorm patterns in different return periods,and the watersheds with higher vegetation coverage have smaller runoff coefficients and flood peak modulus.Under different return periods and different design rainstorm conditions,the runoff coefficient and flood peak modulus present different characteristics,which have a certain impact on the formation of runoff in the basin.In the Guankou basin,its peak discharge and peak emergence time show a certain trend with the increase of the return period and the different design rainstorm patterns.Observing the changes in the flooding process under different recurrence periods and different design rainstorm conditions is of great significance for mastering the law of storm floods in mountainous areas.
The global warming trend has intensified,increasing the frequency of heavy rain disasters in China,making the mountain watershed easy to produce flash floods.Rain pattern was one of the influencing factors of mountain torrent disaster.Applying the designed rainstorm pattern to watersheds with different vegetation coverage rates in mountainous areas may help to analyze the impact of design rainstorm patterns in different return periods in watersheds.Thus it is important to reveal the response law of different vegetation coverage basins in mountainous areas to different rainstorms,and provide technical support for a more reasonable analysis of mountain rainstorms and floods. The Dayi,Guankou,and Hanwangchang watersheds in Sichuan Province were taken as the study area,and the spatio-temporal variable source mixed runoff generation model was used.The runoff coefficient,flood peak modulus,average runoff coefficient,and average flood peak modulus were used to design rainstorms for different return periods.Analysis of the hydrological process was formed by precipitation under different vegetation coverage in the watershed under different vegetation conditions. In the three small watersheds of Sichuan Province simulated by the spatio-temporal variable source mixed runoff generation model,the simulation accuracy evaluation index values were within the allowable range,indicating that the spatio-temporal variable source mixed runoff generation model was suitable for flood process simulation in small mountain basins.The runoff coefficient and flood peak modulus showed different characteristics under different return periods and different design rainstorm conditions.Under different return period conditions,the rainfall patterns in the basin show a decreasing trend from the front type,the middle type to the rear type,and the flood peak modulus is increasing.Under different rainstorm designs conditions,the runoff coefficient first increases and then decreases slightly and then tends to a stable state under increase of the return period,and the flood peak modulus increases with the increase of the return period. The watersheds with different vegetation coverage respond differently to the designed rainstorm patterns in different return periods,and the watersheds with higher vegetation coverage have smaller runoff coefficients and flood peak modulus.Under different return periods and different design rainstorm conditions,the runoff coefficient and flood peak modulus present different characteristics,which have a certain impact on the formation of runoff in the basin.In the Guankou basin,its peak discharge and peak emergence time show a certain trend with the increase of the return period and the different design rainstorm patterns.Observing the changes in the flooding process under different recurrence periods and different design rainstorm conditions is of great significance for mastering the law of storm floods in mountainous areas.
MA Qiang
,
LI Zhengmiao
,
XIE Jiabi
,
QIAO Nan
,
ZHANG Qiyi
,
ZHANG Shunfu
,
LIU Changjun
,
ZHENG Huiyang
2022, 20(1):152-159.
Abstract:
With the growth of the infiltrated water amount,the loess matrix suction will decrease,and lead to the reduction of slope shearing strength that lets the slope under an unstable condition and prone to occur landslides or other geotechnical disasters.The variation of the seepage field as one of the important influence factors of slope stability has been widely agreed with the majority of geotechnical scholars.However,most of the simulation analyses were limited to experimental or hypothetical simulation due to the lack of real monitoring data. According to the measurement of loess property in both southern and western slopes,the Geo-Studio software was selected to study and analyze the impact of rainfall seepage on loess slope stability in Baota Mountain.Based on four kinds of geotechnical data ("slow shear","triaxial","effective",and "total stress"),the stability of the western slope of Baota Mountain was analyzed and simulated under different rainfall scenarios. By comprehensively comparing the results simulated by four kinds of loess parameters,the influence of rainfall infiltration on slope stability was relatively lower with "total stress" and "slow shear" parameters.When the rainfall over 100 mm in 24 h,the slope stability decreased abruptly under the condition of "triaxial" and "effective".The "triaxial" test can strictly control the drainage conditions and can obtain the effective shear strength indexes of the soil through the pore water pressure.The base of Baota Mountain is generally stable,and the possibility of having large landslides is relatively lower. However,the potential risk of slope collapse disaster still existed on the Baota Mountain.Under extreme climatic conditions,where the accumulated rainfall exceeded 100 mm in 24 h,the surface loess on the slope will be supersaturated,and then prone to have small/mediumscaled collapse.It is recommended to take relevant measures to manage the risk slope of Baota Mountain from the perspective of how to prevent slope erosion and reduce rainfall infiltration on the slope.In addition,combined with the simulation results,a reservation system based on real-time rainfall monitoring should be established to properly carry out disaster prevention.
With the growth of the infiltrated water amount,the loess matrix suction will decrease,and lead to the reduction of slope shearing strength that lets the slope under an unstable condition and prone to occur landslides or other geotechnical disasters.The variation of the seepage field as one of the important influence factors of slope stability has been widely agreed with the majority of geotechnical scholars.However,most of the simulation analyses were limited to experimental or hypothetical simulation due to the lack of real monitoring data. According to the measurement of loess property in both southern and western slopes,the Geo-Studio software was selected to study and analyze the impact of rainfall seepage on loess slope stability in Baota Mountain.Based on four kinds of geotechnical data ("slow shear","triaxial","effective",and "total stress"),the stability of the western slope of Baota Mountain was analyzed and simulated under different rainfall scenarios. By comprehensively comparing the results simulated by four kinds of loess parameters,the influence of rainfall infiltration on slope stability was relatively lower with "total stress" and "slow shear" parameters.When the rainfall over 100 mm in 24 h,the slope stability decreased abruptly under the condition of "triaxial" and "effective".The "triaxial" test can strictly control the drainage conditions and can obtain the effective shear strength indexes of the soil through the pore water pressure.The base of Baota Mountain is generally stable,and the possibility of having large landslides is relatively lower. However,the potential risk of slope collapse disaster still existed on the Baota Mountain.Under extreme climatic conditions,where the accumulated rainfall exceeded 100 mm in 24 h,the surface loess on the slope will be supersaturated,and then prone to have small/mediumscaled collapse.It is recommended to take relevant measures to manage the risk slope of Baota Mountain from the perspective of how to prevent slope erosion and reduce rainfall infiltration on the slope.In addition,combined with the simulation results,a reservation system based on real-time rainfall monitoring should be established to properly carry out disaster prevention.
2022, 20(1):160-170.
Abstract:
Flood disasters are one of the most serious natural disasters in our country.More than two-thirds of cities across the country have experienced rainstorms and floods of varying degrees.In recent years,with the rapid development of urbanization,a series of problems such as drastic changes in the underlying surface,changes in the law of runoff generation and confluence in river basins,and obsolescence of urban drainage facilities have greatly increased the exposure to flood risk.On average,more than 200 cities have flooded every year,and the phenomenon of "city watching the sea" is getting worse. The mathematical model is the main method to calculate and analyze urban rainstorm waterlogging.The main urban area of Changzhou City is taken as the research object to analyze its rainstorm waterlogging risk.Using InfoWorks ICM,according to the topography,river system,underground pipeline,water conservancy project,and engineering scheduling rules of the main urban area of Changzhou City,the hydrological and hydrodynamic,one-dimensional and two-dimensional,river network and pipe network coupling models of the main urban area of Changzhou City are constructed.The scope of the model covers 179.2 km2 of the main urban area of Changzhou City. To ensure the refinement level and simulation accuracy of the model,the river sections in the constructed model are all measured sections,including 113 river channels and 1 154 sections.The pipeline network model covers the entire compilation range of the main urban area of Changzhou City.During the construction of the two-dimensional model,the road elevation was intensively measured,and the distance between points was controlled to be about 100 m to 300 m according to the changes in elevation.A high-precision DEM data was collected to build a ground model .The hydrological model was used to calculate the confluence process.The calculation results of river water level may also affect the pipe network and ground model.The pipe network,river network,and submerged area may exchange water according to the above process,nesting each other and real-time mutual feed,to realize the one and two-dimensional coupling of the river network and pipe network. The mathematical model was calibrated and verified with the 2017 field prototype observation data,and the 2015 flood simulation situation was compared with the actual submerged area and submerged water depth.The verification results show that the maximum absolute error of the calculated water level and the measured water level are both less than 7 cm,and the shape of the calculated water level curve matches well with the measured water level sequence.Using the calibrated and verified one and two dimensional coupled model of the refined river network and pipe network in the main urban area of Changzhou City to simulate and analyze the flood inundation and pipeline operation load under the maximum 24 h design rainstorm conditions in 50 years,100 years,and 200 years.The results show that:The inundation area is 29.04 km2,31.48 km2,and 34.70 km2,respectively,under the maximum design rainstorm of 24 h.The submerged water depth is mainly distributed in the range of 0.05 to 0.30 m,accounting for about 70% of the total submerged area.The daily maximum rainfall in the region plays a leading role in the process of water accumulation,which is characterized by a large area of waterlogging in torrential rain and a small submerged water depth.Most of the pipelines in the main urban area are overloaded.Among them,the percentages of overloaded pipelines due to the jacking of downstream pipelines were 65.99%,65.65%,and 65.39%,respectively,and the proportions of overloaded pipelines due to the limitation of the flow capacity of the pipeline itself accounted for 33.09%,33.46%,and 33.74%.Short-duration heavy rainfall is the main cause of overloading of the pipeline network.The research results provide a basis for predicting the risk of rainstorm waterlogging in Changzhou City,guiding the decision-making of flood control and drainage,and also provide a reference for the urban development and construction of Changzhou City.
Flood disasters are one of the most serious natural disasters in our country.More than two-thirds of cities across the country have experienced rainstorms and floods of varying degrees.In recent years,with the rapid development of urbanization,a series of problems such as drastic changes in the underlying surface,changes in the law of runoff generation and confluence in river basins,and obsolescence of urban drainage facilities have greatly increased the exposure to flood risk.On average,more than 200 cities have flooded every year,and the phenomenon of "city watching the sea" is getting worse. The mathematical model is the main method to calculate and analyze urban rainstorm waterlogging.The main urban area of Changzhou City is taken as the research object to analyze its rainstorm waterlogging risk.Using InfoWorks ICM,according to the topography,river system,underground pipeline,water conservancy project,and engineering scheduling rules of the main urban area of Changzhou City,the hydrological and hydrodynamic,one-dimensional and two-dimensional,river network and pipe network coupling models of the main urban area of Changzhou City are constructed.The scope of the model covers 179.2 km2 of the main urban area of Changzhou City. To ensure the refinement level and simulation accuracy of the model,the river sections in the constructed model are all measured sections,including 113 river channels and 1 154 sections.The pipeline network model covers the entire compilation range of the main urban area of Changzhou City.During the construction of the two-dimensional model,the road elevation was intensively measured,and the distance between points was controlled to be about 100 m to 300 m according to the changes in elevation.A high-precision DEM data was collected to build a ground model .The hydrological model was used to calculate the confluence process.The calculation results of river water level may also affect the pipe network and ground model.The pipe network,river network,and submerged area may exchange water according to the above process,nesting each other and real-time mutual feed,to realize the one and two-dimensional coupling of the river network and pipe network. The mathematical model was calibrated and verified with the 2017 field prototype observation data,and the 2015 flood simulation situation was compared with the actual submerged area and submerged water depth.The verification results show that the maximum absolute error of the calculated water level and the measured water level are both less than 7 cm,and the shape of the calculated water level curve matches well with the measured water level sequence.Using the calibrated and verified one and two dimensional coupled model of the refined river network and pipe network in the main urban area of Changzhou City to simulate and analyze the flood inundation and pipeline operation load under the maximum 24 h design rainstorm conditions in 50 years,100 years,and 200 years.The results show that:The inundation area is 29.04 km2,31.48 km2,and 34.70 km2,respectively,under the maximum design rainstorm of 24 h.The submerged water depth is mainly distributed in the range of 0.05 to 0.30 m,accounting for about 70% of the total submerged area.The daily maximum rainfall in the region plays a leading role in the process of water accumulation,which is characterized by a large area of waterlogging in torrential rain and a small submerged water depth.Most of the pipelines in the main urban area are overloaded.Among them,the percentages of overloaded pipelines due to the jacking of downstream pipelines were 65.99%,65.65%,and 65.39%,respectively,and the proportions of overloaded pipelines due to the limitation of the flow capacity of the pipeline itself accounted for 33.09%,33.46%,and 33.74%.Short-duration heavy rainfall is the main cause of overloading of the pipeline network.The research results provide a basis for predicting the risk of rainstorm waterlogging in Changzhou City,guiding the decision-making of flood control and drainage,and also provide a reference for the urban development and construction of Changzhou City.
2022, 20(1):171-179.
Abstract:
The Huaihe River is a seventh major river,located in eastern China.The major floods in 1954,1991,2003,and 2007 had seriously endangered the lives and property of the people in the Huaihe River basin.The Huaihe River basin in Anhui Province had flooded areas exceeding 1 million hm2.The average annual flood disaster area in 61 years was 217,200 hm2,accounting for 5% of the cultivated land area in 2010.To reduce the flood disaster loss,19 Huaihe River control projects were carried out from 1991 to 2007,and 38 major tasks for the Huaihe River control were completed from 2013 to 2017.The flood control and disaster reduction work in the Huaihe River basin has made renowned achievements and produced tremendous results.Floods in the mainstream of the Huaihe River lasted for a long time with large volume,frequent flood disasters occurred in the basin.Under the influence of climate change and human activities,the flood characteristics of the mainstream of the Huaihe River have changed to varying degrees.The analysis of the characteristics of flood changes in the mainstream of the Huaihe River can provide an important basis for the flood control planning and is of great significance. Based on the four hydrological stations (Wangjiaba,Lutaizi,Wujiadu,and Xiaoliuxiang),the annual maximum peak discharge sequence was used to study the objectives using the Kendall ranking test,Spearman ranking test,linear trend regression test,and MannKendall test,sequential cluster,rank-sum test,wavelet analysis to analyze the trend,sudden change and periodic change of the flood series of typical stations on the mainstream of the Huaihe River.The final results are as follows: The annual maximum peak discharge rate of Wangjiaba station is -33.08 m3/(s·a),Kendall ranking test value is 1.31<1.96,Spearman ranking test value is 1.23<1.64,linear trend regression test value is 1.49<1.64;the annual maximum peak discharge rate of Lutaizi station is -5.4 m3/(s·a),the Kendall ranking test value is 0.39<1.96,the Spearman ranking test value is 0.42<1.64,and the linear trend regression test value is 0.25<1.64;the annual maximum peak discharge rate of Wujiadu station is 16.88 m3/(s·a),the Kendall ranking test value is 1.84<1.96,the Spearman ranking test value is 1.66>1.64,and the linear trend regression test value is 1.05<1.64;the annual maximum peak discharge rate of the Xiaoliuxiang station is 22.24 m3/(s·a),the Kendall ranking test value is 0.44<1.96,the Spearman ranking test value is 0.44<1.64,the linear trend regression test value is 0.67<1.64,respectively.There are multiple intersections between the curves of Mann-Kendall statistical values UF and UB of the annual maximum peak discharge sequence at each station.The sequential cluster method and rank-sum test method are used to judge the mutation points.The Morlet wavelet analysis was used to analyze the periodic variation characteristics of the annual maximum peak discharge of the four hydrological stations Wangjiaba,Lutaizi,Wujiadu and Xiaoliuxiang in the Huaihe River basin,and finally the contour maps of the real part of the Morlet wavelet transform coefficients and the Morlet wavelet variance maps were completed. The results show that the annual maximum peak discharge in this area had a relatively large change,and the deviation coefficient of the upstream was generally larger than that of the downstream.The upstream sequence had a greater degree of dispersion.Among them,the Wangjiaba and Lutaizi Stations showed an insignificant downward trend,and Wujiadu and Xiaoliuxiang stations showed an insignificant upward trend.The mutation points at the Wangjiaba site were in 1985,1993 and 2010,the mutation points at the Lutaizi site were in 1957,2002 and 2014.The mutation points at the Wujiadu site were 1995,and the mutation points at the Xiaoliuxiang site were 1995.Wangjiaba Station mainly has 4 scale cycles of 3.8 a,8.14 a,14.22 a and 22.32 a.Lutaizi Station mainly has 2 scale cycles of 5.13 a and 15.32 a;Wujiadu Station mainly has 2 scale cycles of 5.18 a and 20.32 a,while Xiaoliuxiang Station mainly has 4.7 a,10.15 a and the period of the three scales of 17.25 a.
The Huaihe River is a seventh major river,located in eastern China.The major floods in 1954,1991,2003,and 2007 had seriously endangered the lives and property of the people in the Huaihe River basin.The Huaihe River basin in Anhui Province had flooded areas exceeding 1 million hm2.The average annual flood disaster area in 61 years was 217,200 hm2,accounting for 5% of the cultivated land area in 2010.To reduce the flood disaster loss,19 Huaihe River control projects were carried out from 1991 to 2007,and 38 major tasks for the Huaihe River control were completed from 2013 to 2017.The flood control and disaster reduction work in the Huaihe River basin has made renowned achievements and produced tremendous results.Floods in the mainstream of the Huaihe River lasted for a long time with large volume,frequent flood disasters occurred in the basin.Under the influence of climate change and human activities,the flood characteristics of the mainstream of the Huaihe River have changed to varying degrees.The analysis of the characteristics of flood changes in the mainstream of the Huaihe River can provide an important basis for the flood control planning and is of great significance. Based on the four hydrological stations (Wangjiaba,Lutaizi,Wujiadu,and Xiaoliuxiang),the annual maximum peak discharge sequence was used to study the objectives using the Kendall ranking test,Spearman ranking test,linear trend regression test,and MannKendall test,sequential cluster,rank-sum test,wavelet analysis to analyze the trend,sudden change and periodic change of the flood series of typical stations on the mainstream of the Huaihe River.The final results are as follows: The annual maximum peak discharge rate of Wangjiaba station is -33.08 m3/(s·a),Kendall ranking test value is 1.31<1.96,Spearman ranking test value is 1.23<1.64,linear trend regression test value is 1.49<1.64;the annual maximum peak discharge rate of Lutaizi station is -5.4 m3/(s·a),the Kendall ranking test value is 0.39<1.96,the Spearman ranking test value is 0.42<1.64,and the linear trend regression test value is 0.25<1.64;the annual maximum peak discharge rate of Wujiadu station is 16.88 m3/(s·a),the Kendall ranking test value is 1.84<1.96,the Spearman ranking test value is 1.66>1.64,and the linear trend regression test value is 1.05<1.64;the annual maximum peak discharge rate of the Xiaoliuxiang station is 22.24 m3/(s·a),the Kendall ranking test value is 0.44<1.96,the Spearman ranking test value is 0.44<1.64,the linear trend regression test value is 0.67<1.64,respectively.There are multiple intersections between the curves of Mann-Kendall statistical values UF and UB of the annual maximum peak discharge sequence at each station.The sequential cluster method and rank-sum test method are used to judge the mutation points.The Morlet wavelet analysis was used to analyze the periodic variation characteristics of the annual maximum peak discharge of the four hydrological stations Wangjiaba,Lutaizi,Wujiadu and Xiaoliuxiang in the Huaihe River basin,and finally the contour maps of the real part of the Morlet wavelet transform coefficients and the Morlet wavelet variance maps were completed. The results show that the annual maximum peak discharge in this area had a relatively large change,and the deviation coefficient of the upstream was generally larger than that of the downstream.The upstream sequence had a greater degree of dispersion.Among them,the Wangjiaba and Lutaizi Stations showed an insignificant downward trend,and Wujiadu and Xiaoliuxiang stations showed an insignificant upward trend.The mutation points at the Wangjiaba site were in 1985,1993 and 2010,the mutation points at the Lutaizi site were in 1957,2002 and 2014.The mutation points at the Wujiadu site were 1995,and the mutation points at the Xiaoliuxiang site were 1995.Wangjiaba Station mainly has 4 scale cycles of 3.8 a,8.14 a,14.22 a and 22.32 a.Lutaizi Station mainly has 2 scale cycles of 5.13 a and 15.32 a;Wujiadu Station mainly has 2 scale cycles of 5.18 a and 20.32 a,while Xiaoliuxiang Station mainly has 4.7 a,10.15 a and the period of the three scales of 17.25 a.
2022, 20(1):180-190.
Abstract:
The bottom elevation of lower Yellow River main channel has been greatly reduced because of Xiaolangdi Reservoir several water and sand adjustments,resulting in a significant drop in the water level of the Yellow River,making the submerged depth of the horn nozzle of the pumping station into the pool that does not meet the pump requirements.The pump runs at an ultra-low water level,which causes deterioration in the flow pattern of the intake pool and changes in cavitation conditions,resulting in serious cavitation of the water inlet horn and pump impeller,unit vibration,and degradation of pump performance,etc.,which will force the unit in severe cases.The flow rate of the inlet water of the pumping station directly affects the flow pattern of the inlet pool of the pumping station.The turbulent flow pattern is often accompanied by the generation of vortices,which will not only reduce the performance of the pump but even cause the pump to cavitation,vibration,and unable to work. To explore the flow rate of the pumping station and the generation and development of the flow pattern and vortex of the pumping station′s intake pool,combined with the actual operation of the pumping station,the NX UG100 software is used to construct the drainage channel,fore pool,intake pool,and intake pipe.Taking pumping station water intakes physical model,and a three-dimensional turbulence mathematical model of the corresponding physical model is established.The calculation adopts the Reynolds NS equation,VOF model,and unsteady SSTk-ω turbulence model.The algorithm adopts the simple algorithm of flow field calculation.The discrete method adopts a limited volume method.The gradient adopts the least square method based on grid unit,the momentum,turbulent kinetic energy and turbulence dissipation rate adopt the second-order upwind style respectively.The inlet adopts the velocity inlet boundary condition,and the outlet adopts the velocity outlet boundary conditions,the water surface of the front pool and the inlet sluice chamber are set as the pressure outlet boundary conditions,and the atmospheric pressure reference point is selected as the contact point between the free water surface and the air.The rest are set as the wall boundary conditions,including: the front sump,the inlet sluice chamber,the side and bottom wall,the four walls of the inlet flow channel,the bell mouth and the outlet pipe wall are automatically processed by the SSTk-ωmodel until the flow difference between the inlet and outlet no longer changes or the water surface is stable,while the flow field is considered to reach in a stable state.9 different influent flow rates are selected,the characteristics of the influent water flow of the pumping station are numerically simulated,and the distribution of the influent flow field,the change of vortex,and the distribution law of the pumping station are analyzed under different influent flow rates. The research results show that when the inlet water velocity is between 0.322 2 m/s and 0.564 2 m/s,the intensity of the vortex on the surface of the pumping station increases with the increase of the inlet water velocity.When the inlet water velocity is 0.322 2 m/s~0.401 6 m/s,Type Ⅲ,and Ⅳ vortex appears in the inlet pool.Type Ⅴ vortex appears when the inflow velocity is 0.483 5 m/s,and Type Ⅵ vortex appears when the inflow velocity is 0.520 8 m/s~0.564 2 m/s. By comparing with the model test results,the two results are consistent.The research results can provide a reference for the engineering design of the pumping station.
The bottom elevation of lower Yellow River main channel has been greatly reduced because of Xiaolangdi Reservoir several water and sand adjustments,resulting in a significant drop in the water level of the Yellow River,making the submerged depth of the horn nozzle of the pumping station into the pool that does not meet the pump requirements.The pump runs at an ultra-low water level,which causes deterioration in the flow pattern of the intake pool and changes in cavitation conditions,resulting in serious cavitation of the water inlet horn and pump impeller,unit vibration,and degradation of pump performance,etc.,which will force the unit in severe cases.The flow rate of the inlet water of the pumping station directly affects the flow pattern of the inlet pool of the pumping station.The turbulent flow pattern is often accompanied by the generation of vortices,which will not only reduce the performance of the pump but even cause the pump to cavitation,vibration,and unable to work. To explore the flow rate of the pumping station and the generation and development of the flow pattern and vortex of the pumping station′s intake pool,combined with the actual operation of the pumping station,the NX UG100 software is used to construct the drainage channel,fore pool,intake pool,and intake pipe.Taking pumping station water intakes physical model,and a three-dimensional turbulence mathematical model of the corresponding physical model is established.The calculation adopts the Reynolds NS equation,VOF model,and unsteady SSTk-ω turbulence model.The algorithm adopts the simple algorithm of flow field calculation.The discrete method adopts a limited volume method.The gradient adopts the least square method based on grid unit,the momentum,turbulent kinetic energy and turbulence dissipation rate adopt the second-order upwind style respectively.The inlet adopts the velocity inlet boundary condition,and the outlet adopts the velocity outlet boundary conditions,the water surface of the front pool and the inlet sluice chamber are set as the pressure outlet boundary conditions,and the atmospheric pressure reference point is selected as the contact point between the free water surface and the air.The rest are set as the wall boundary conditions,including: the front sump,the inlet sluice chamber,the side and bottom wall,the four walls of the inlet flow channel,the bell mouth and the outlet pipe wall are automatically processed by the SSTk-ωmodel until the flow difference between the inlet and outlet no longer changes or the water surface is stable,while the flow field is considered to reach in a stable state.9 different influent flow rates are selected,the characteristics of the influent water flow of the pumping station are numerically simulated,and the distribution of the influent flow field,the change of vortex,and the distribution law of the pumping station are analyzed under different influent flow rates. The research results show that when the inlet water velocity is between 0.322 2 m/s and 0.564 2 m/s,the intensity of the vortex on the surface of the pumping station increases with the increase of the inlet water velocity.When the inlet water velocity is 0.322 2 m/s~0.401 6 m/s,Type Ⅲ,and Ⅳ vortex appears in the inlet pool.Type Ⅴ vortex appears when the inflow velocity is 0.483 5 m/s,and Type Ⅵ vortex appears when the inflow velocity is 0.520 8 m/s~0.564 2 m/s. By comparing with the model test results,the two results are consistent.The research results can provide a reference for the engineering design of the pumping station.
2022, 20(1):191-200.
Abstract:
Since the 21st century,economic globalization and technological reform have promoted the deep integration of population flow,capital flow,resource flow,and technology flow among countries around the globe.The ecological and environmental problems brought by economic development and population pressure have gradually become global problems.Since China′s reform and opening up,with the rapid urbanization process,China realizes the jumping development of the economy,lacks of enough attention to the ecological environment protection in urbanization,and faces enormous pressure of ecological security, excessive consumption of resources,vegetation degeneration,water pollution and ecological deterioration problems.The Yellow River basin is an important economic belt and grain base in China.With the rapid economic development,the ecological environment has been damaged and the ecological habitat of the river basin has been seriously damaged.Ecological protection and high-quality development of the Yellow River basin was upgraded to a major national strategy in 2019,providing a new opportunity for the basin to explore a synergistic model of ecological protection and high-quality development. To find a new way of high-quality development under urbanization development and ecological protection,it is urgent to clarify the interaction between urbanization and ecological security.The evaluation index system of urbanization level from four dimensions of population urbanization,economic urbanization,social urbanization and spatial urbanization is constructed.The urbanization level and ecological security index of nine provinces of Yellow River basin was calculated using analytic hierarchy process and entropy weight method to determine index.The comprehensive weightand grey correlation model was used to calculate urbanization level and ecological safety criterion layer and index correlation from 2008 to 2018 to clarify the influence of internal factors between the two systems.Finally,a decoupling model is constructed to explore the degree of decoupling between the two systems. The urbanization level and ecological security of the nine provinces and regions in the Yellow River basin showed an upward trend.UDI increased from 0.24 to 0.58,with an average annual increase of 9.23%.ESI increased from 0.30 to 0.41,with an annual growth rate of 3.2%.The correlation between urbanization level and ecological security system is higher than 0.6,between medium correlation and strong correlation,and has a strong interaction.Population urbanization exerts the greatest stress on ecological security,and the correlation value is 0.741.Ecological governance exerts the strongest constraint on urbanization development,and the correlation value is 0.726. The conclusions through an analysis were: 1) Urbanization level and ecological security level continue to grow,but the growth rate gradually decreases,indicating that the development level of the two systems is hindered to different degrees.2) There is a strong interaction between urbanization level and ecological security system,and the constraint effect of ecological security on urbanization development may stronger in the future.3) There is a cyclic alternating phenomenon of expansionary coupling and strong and weak decoupling,mainly with decoupling.Therefore,it is necessary to coordinate the relationship between protection and development,strengthen the investment in ecological management,strictly limit the pollutant discharge of enterprises,and develop green and sustainable industries.A green and sustainable ecological industry chain will be built based on local conditions,the ecological compensation mechanisms will be established and improved,and the constraints and bottlenecks of ecological protection on the urbanization process will be broken.
Since the 21st century,economic globalization and technological reform have promoted the deep integration of population flow,capital flow,resource flow,and technology flow among countries around the globe.The ecological and environmental problems brought by economic development and population pressure have gradually become global problems.Since China′s reform and opening up,with the rapid urbanization process,China realizes the jumping development of the economy,lacks of enough attention to the ecological environment protection in urbanization,and faces enormous pressure of ecological security, excessive consumption of resources,vegetation degeneration,water pollution and ecological deterioration problems.The Yellow River basin is an important economic belt and grain base in China.With the rapid economic development,the ecological environment has been damaged and the ecological habitat of the river basin has been seriously damaged.Ecological protection and high-quality development of the Yellow River basin was upgraded to a major national strategy in 2019,providing a new opportunity for the basin to explore a synergistic model of ecological protection and high-quality development. To find a new way of high-quality development under urbanization development and ecological protection,it is urgent to clarify the interaction between urbanization and ecological security.The evaluation index system of urbanization level from four dimensions of population urbanization,economic urbanization,social urbanization and spatial urbanization is constructed.The urbanization level and ecological security index of nine provinces of Yellow River basin was calculated using analytic hierarchy process and entropy weight method to determine index.The comprehensive weightand grey correlation model was used to calculate urbanization level and ecological safety criterion layer and index correlation from 2008 to 2018 to clarify the influence of internal factors between the two systems.Finally,a decoupling model is constructed to explore the degree of decoupling between the two systems. The urbanization level and ecological security of the nine provinces and regions in the Yellow River basin showed an upward trend.UDI increased from 0.24 to 0.58,with an average annual increase of 9.23%.ESI increased from 0.30 to 0.41,with an annual growth rate of 3.2%.The correlation between urbanization level and ecological security system is higher than 0.6,between medium correlation and strong correlation,and has a strong interaction.Population urbanization exerts the greatest stress on ecological security,and the correlation value is 0.741.Ecological governance exerts the strongest constraint on urbanization development,and the correlation value is 0.726. The conclusions through an analysis were: 1) Urbanization level and ecological security level continue to grow,but the growth rate gradually decreases,indicating that the development level of the two systems is hindered to different degrees.2) There is a strong interaction between urbanization level and ecological security system,and the constraint effect of ecological security on urbanization development may stronger in the future.3) There is a cyclic alternating phenomenon of expansionary coupling and strong and weak decoupling,mainly with decoupling.Therefore,it is necessary to coordinate the relationship between protection and development,strengthen the investment in ecological management,strictly limit the pollutant discharge of enterprises,and develop green and sustainable industries.A green and sustainable ecological industry chain will be built based on local conditions,the ecological compensation mechanisms will be established and improved,and the constraints and bottlenecks of ecological protection on the urbanization process will be broken.
2022, 20(1):201-208.
Abstract:
The river channel of wandering type is wide and shallow;the water flow is scattered,the mainstream migrates uncertainly,the river regime changes violently,which is extremely unfavorable to flood control.In order to ensure the flood control safety on both banks of the lower Yellow River,the control and guide project was built in the curved section of the lower Yellow River as early as in 1950s,and gradually extended to the transition section,and finally successfully renovated in the wandering section.In recent years,with the continuous construction of the wandering channel regulation project in the lower Yellow River and the change of water and sand situation,the cross-section shape of the river has changed greatly.It is momentous to study the influence of river regulation projects on the shape of wandering channels,especially the relationship between engineering density and shape parameters of the river sections. Based on the construction process,measured discharge,and section topographic data of the river regulation project of the wandering river in the lower Yellow River from 1960 to 2014,the length and density of the river regulation project in different periods are calculated,and the relationship between the engineering density and the morphological indexes (width,depth and river phase coefficient) of each section in each period is established under the condition of the same discharge.The influence of river regulation projects in different periods on the evolution of river section morphology is analyzed. The results show that the density of the regulation project of the wandering reach of the lower Yellow River increases year by year,and now the density of the regulation project has reached over 70%.When the density of the regulation works is small,the wandering characteristics of the river reach are not completely controlled,and the width of the river varies greatly under the same discharge;after the river remediation,especially in the river section with complete engineering construction and high engineering density,the width of the river at the same flow is significantly narrowed.The regulation works have a certain impact on the section water depth.Under the same water and sediment conditions,the construction of the regulation project constrains the lateral expansion of the flow,and the flow begins to wash down the riverbed,which makes the water depth of the section increase gradually.Before river regulation,the river phase coefficient of the wandering river course and its variation range are all large.After river regulation,the river phase coefficient of cross-section decreases and tends to be stable as the density of regulation project increases under the condition of same discharge,which shows that the perfect river regulation project makes the cross-section form develop to narrow and deep direction,and the river regime is more stable. It is shown that the river regulation project can obviously improve the river section when the river regulation project reaches a certain density,and limit the wandering characteristics of the river section.With the increase of the density of the river regulation project,the width of the river decreases,the depth of water increases,and the coefficient of the river phase decreases.When the density of the river regulation project is low,the river regime can not be controlled effectively,and the wandering characteristics of the river section are prominent,the river width,water depth and river facies coefficient under the same flow change frequently and greatly.
The river channel of wandering type is wide and shallow;the water flow is scattered,the mainstream migrates uncertainly,the river regime changes violently,which is extremely unfavorable to flood control.In order to ensure the flood control safety on both banks of the lower Yellow River,the control and guide project was built in the curved section of the lower Yellow River as early as in 1950s,and gradually extended to the transition section,and finally successfully renovated in the wandering section.In recent years,with the continuous construction of the wandering channel regulation project in the lower Yellow River and the change of water and sand situation,the cross-section shape of the river has changed greatly.It is momentous to study the influence of river regulation projects on the shape of wandering channels,especially the relationship between engineering density and shape parameters of the river sections. Based on the construction process,measured discharge,and section topographic data of the river regulation project of the wandering river in the lower Yellow River from 1960 to 2014,the length and density of the river regulation project in different periods are calculated,and the relationship between the engineering density and the morphological indexes (width,depth and river phase coefficient) of each section in each period is established under the condition of the same discharge.The influence of river regulation projects in different periods on the evolution of river section morphology is analyzed. The results show that the density of the regulation project of the wandering reach of the lower Yellow River increases year by year,and now the density of the regulation project has reached over 70%.When the density of the regulation works is small,the wandering characteristics of the river reach are not completely controlled,and the width of the river varies greatly under the same discharge;after the river remediation,especially in the river section with complete engineering construction and high engineering density,the width of the river at the same flow is significantly narrowed.The regulation works have a certain impact on the section water depth.Under the same water and sediment conditions,the construction of the regulation project constrains the lateral expansion of the flow,and the flow begins to wash down the riverbed,which makes the water depth of the section increase gradually.Before river regulation,the river phase coefficient of the wandering river course and its variation range are all large.After river regulation,the river phase coefficient of cross-section decreases and tends to be stable as the density of regulation project increases under the condition of same discharge,which shows that the perfect river regulation project makes the cross-section form develop to narrow and deep direction,and the river regime is more stable. It is shown that the river regulation project can obviously improve the river section when the river regulation project reaches a certain density,and limit the wandering characteristics of the river section.With the increase of the density of the river regulation project,the width of the river decreases,the depth of water increases,and the coefficient of the river phase decreases.When the density of the river regulation project is low,the river regime can not be controlled effectively,and the wandering characteristics of the river section are prominent,the river width,water depth and river facies coefficient under the same flow change frequently and greatly.
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