Most view articles
2021, 19(4):625-635.
Abstract:
The hardening of the urban underlying surface and its hydrological effects have aroused widespread concern in the international community.The communication channels between the water sources are hindered or even cut off by the impervious surface,changing the natural hydrological process.Exploring the impact mechanism of urban underlying surface changes on runoff processes is of critical significance to regional flood control and water safety construction. The central urban area of Jiujiang were focused on.The time variant gain model was improved to analyze the changes of underlying surface and the evolution trend of multi-year runoff.We aimed to quantify the response relationship between runoff process and impervious surface expansion was aimed to qualified,and support for understanding the hydrological effects of impervious surface expansion was provided in typical cities in the middle reaches of the Yangtze River. ENVI and ArcGIS software was employed to realize the interpretation and classification of remote sensing images,and the variation of land use dynamics was analyzed in the study area from 1987 to 2018.In view of the difference in runoff features of underlying surfaces based on the time variant gain model,an improvement on the structure of the original model was made by dividing underlying surfaces into permeable area and impervious area.The former included arable land,green land,and water bodies,while the latter referred to the impervious surfaces in construction land.The urban time variant gain model was established to calculate the runoff coefficient over the years and the runoff process of a typical year. From 1987 to 2018,the main features of underlying changes in the studying area are listed as follows:(1) The construction land expanded from 8.23 km2 to 189.93 km2,with the fastest expansion rate in the period from 2009 to 2012.(2) A fluctuation occurred in the change of arable land, woodland and grassland, which occupied a large percentage of the total area.Before 2012,the area of arable land increased from 601.42 km2 to 806.72 km2,and the proportion of woodland and grassland decreased to 145%.From 2012 to 2018,the area of arable land has declined while the proportion of woodland and grassland increased to 24.9%.(3) The water body has shown a shrinking trend since 2006,and decreased from 217.02 km2 to 168.28 km2 from 2015 to 2018. Model calculations based on rainfall data from meteorological stations shows some fluctuations in the increasing trend of the runoff coefficient under the circumstance of impervious area expansion year by year.From 1995 to 2000,the increase in the proportion of green space caused the runoff coefficient to decrease instead.This finding revealed that runoff generation process in the study area is influenced by the changes of various underlying surface types and meteorological conditions.Under the same meteorological conditions,a high consistency existed between the change characteristics of runoff and impervious surface ratio over the years.The runoff coefficient ascended from 0.31 to 0.38,and the runoff depth increased from 44487 mm to 557.76 mm,respectively.In a typical rainstorm event,the peak flow has increased from 1 504.64 m3/s to 1 649.77 m3/s from 1987 to 2018,while the flow curve dropped in some part of 2006 and 2015,which could be attributed to the increase of green land and water bodies that acted as rainwater saver in the early rainy period. Conclusions(1) The land use in the study area shows a transforming trend from pervious to impervious area.There′s a fluctuation in the area of arable land, woodland and grassland and a shrinking trend in the water body.Especially, the area of construction land has been increasing year by year. (2) The influence factors of runoff coefficient is a combination of the underlying surface changes and the rainfall process,while the impervious surface ratio is dominant in the study area. Under the same meteorological conditions,the proportion of impervious area is increased from 0.49% to 10.58%, and the runoff coefficient is ascended from 0.31 to 0.38 from 1987 to 2018 in the study area. (3) Under a typical rainstorm event, the peak flow is increased by 10%,the flood process line became steeper,and the recession process was significantly slowed down from 1987 to 2018.Green land and water bodies could alleviate the amplification effect of runoff brought about by the urbanization process to a certain extent.
The hardening of the urban underlying surface and its hydrological effects have aroused widespread concern in the international community.The communication channels between the water sources are hindered or even cut off by the impervious surface,changing the natural hydrological process.Exploring the impact mechanism of urban underlying surface changes on runoff processes is of critical significance to regional flood control and water safety construction. The central urban area of Jiujiang were focused on.The time variant gain model was improved to analyze the changes of underlying surface and the evolution trend of multi-year runoff.We aimed to quantify the response relationship between runoff process and impervious surface expansion was aimed to qualified,and support for understanding the hydrological effects of impervious surface expansion was provided in typical cities in the middle reaches of the Yangtze River. ENVI and ArcGIS software was employed to realize the interpretation and classification of remote sensing images,and the variation of land use dynamics was analyzed in the study area from 1987 to 2018.In view of the difference in runoff features of underlying surfaces based on the time variant gain model,an improvement on the structure of the original model was made by dividing underlying surfaces into permeable area and impervious area.The former included arable land,green land,and water bodies,while the latter referred to the impervious surfaces in construction land.The urban time variant gain model was established to calculate the runoff coefficient over the years and the runoff process of a typical year. From 1987 to 2018,the main features of underlying changes in the studying area are listed as follows:(1) The construction land expanded from 8.23 km2 to 189.93 km2,with the fastest expansion rate in the period from 2009 to 2012.(2) A fluctuation occurred in the change of arable land, woodland and grassland, which occupied a large percentage of the total area.Before 2012,the area of arable land increased from 601.42 km2 to 806.72 km2,and the proportion of woodland and grassland decreased to 145%.From 2012 to 2018,the area of arable land has declined while the proportion of woodland and grassland increased to 24.9%.(3) The water body has shown a shrinking trend since 2006,and decreased from 217.02 km2 to 168.28 km2 from 2015 to 2018. Model calculations based on rainfall data from meteorological stations shows some fluctuations in the increasing trend of the runoff coefficient under the circumstance of impervious area expansion year by year.From 1995 to 2000,the increase in the proportion of green space caused the runoff coefficient to decrease instead.This finding revealed that runoff generation process in the study area is influenced by the changes of various underlying surface types and meteorological conditions.Under the same meteorological conditions,a high consistency existed between the change characteristics of runoff and impervious surface ratio over the years.The runoff coefficient ascended from 0.31 to 0.38,and the runoff depth increased from 44487 mm to 557.76 mm,respectively.In a typical rainstorm event,the peak flow has increased from 1 504.64 m3/s to 1 649.77 m3/s from 1987 to 2018,while the flow curve dropped in some part of 2006 and 2015,which could be attributed to the increase of green land and water bodies that acted as rainwater saver in the early rainy period. Conclusions(1) The land use in the study area shows a transforming trend from pervious to impervious area.There′s a fluctuation in the area of arable land, woodland and grassland and a shrinking trend in the water body.Especially, the area of construction land has been increasing year by year. (2) The influence factors of runoff coefficient is a combination of the underlying surface changes and the rainfall process,while the impervious surface ratio is dominant in the study area. Under the same meteorological conditions,the proportion of impervious area is increased from 0.49% to 10.58%, and the runoff coefficient is ascended from 0.31 to 0.38 from 1987 to 2018 in the study area. (3) Under a typical rainstorm event, the peak flow is increased by 10%,the flood process line became steeper,and the recession process was significantly slowed down from 1987 to 2018.Green land and water bodies could alleviate the amplification effect of runoff brought about by the urbanization process to a certain extent.
2017, 15(6):1-10.
Abstract:
As the potential evapotranspiration (PET) is one of the important factors in the energy cycle and hydrological cycle, the accurate estimation of PET has important practical significance. The FAO56-PM method can give efficient estimation of PET; however, its applicability is constrained as it requires a large amount of data. Different PET estimation methods have been proposed and the applicability of these methods should be tested before they are applied in a typical region. In this study, we attempted to examine the efficiency of 7 PET estimation methods in spatial and temporal dimensions in the upper and middle reaches of Hanjiang River Basin using the daily meteorological data during 1961-2013. The results showed that the radiation-based methods were the optimal choice, followed by the combination method, and the temperature-based methods were the least suitable choice for the PET estimation in the study area. Among these estimation methods, the Makkink method and the Priestley-Taylor method showed the best applicability and highest precision in the study area, while the McCloud method showed the worst applicability and largest error.
As the potential evapotranspiration (PET) is one of the important factors in the energy cycle and hydrological cycle, the accurate estimation of PET has important practical significance. The FAO56-PM method can give efficient estimation of PET; however, its applicability is constrained as it requires a large amount of data. Different PET estimation methods have been proposed and the applicability of these methods should be tested before they are applied in a typical region. In this study, we attempted to examine the efficiency of 7 PET estimation methods in spatial and temporal dimensions in the upper and middle reaches of Hanjiang River Basin using the daily meteorological data during 1961-2013. The results showed that the radiation-based methods were the optimal choice, followed by the combination method, and the temperature-based methods were the least suitable choice for the PET estimation in the study area. Among these estimation methods, the Makkink method and the Priestley-Taylor method showed the best applicability and highest precision in the study area, while the McCloud method showed the worst applicability and largest error.
2014, 12(2):20-24.
Abstract:
Sensitivity analysis was performed to analyze the inputs and outputs of the complex model and system qualitatively and quantitatively, which can benefit the inspection of model structure, identification of model parameters, and model application. In this paper, Sobol method was applied to evaluate the sensitivity of single parameter and multiple parameters of the model in the Huanren reservoir catchment. The objective functions of sensitivity analysis included the deterministic coefficients and error coefficients of total water, low flow, and high flow. The results showed that the sensitivity of parameters was different under different objective functions, and Sobol method can provide the sensitivity for all parameters and sensitivity between each parameter, which is useful for sensitivity analysis of hydrological models.
Sensitivity analysis was performed to analyze the inputs and outputs of the complex model and system qualitatively and quantitatively, which can benefit the inspection of model structure, identification of model parameters, and model application. In this paper, Sobol method was applied to evaluate the sensitivity of single parameter and multiple parameters of the model in the Huanren reservoir catchment. The objective functions of sensitivity analysis included the deterministic coefficients and error coefficients of total water, low flow, and high flow. The results showed that the sensitivity of parameters was different under different objective functions, and Sobol method can provide the sensitivity for all parameters and sensitivity between each parameter, which is useful for sensitivity analysis of hydrological models.
2014, 12(2):75-78.
Abstract:
In this paper, the 3-hour and 0.71o grid temperature forecast data of 2 m above ground surface during the period of 1989 to 2009 derived from ERA-Interim reanalysis dataset were applied for the analysis of extremely low and high temperatures in China. Based on the cumulative distribution function and quantile function, the results indicated that the Northeast China, Tibetan Plateau, and Northwest China are the main extremely low-temperature areas, and the extremely low temperature rises along the northwest-southeast direction. Tibetan Plateau is the sole cold area with the extremely high temperatures, while the basins located in Northwest China are the warmest areas. ERA-Interim reanalysis data can represent the spatial distribution of extremely low/high-temperature areas in China. The duration of extreme temperatures can be quantitatively analyzed using the quantile function, which provides reference for the quantitative analysis of extreme climate events.
In this paper, the 3-hour and 0.71o grid temperature forecast data of 2 m above ground surface during the period of 1989 to 2009 derived from ERA-Interim reanalysis dataset were applied for the analysis of extremely low and high temperatures in China. Based on the cumulative distribution function and quantile function, the results indicated that the Northeast China, Tibetan Plateau, and Northwest China are the main extremely low-temperature areas, and the extremely low temperature rises along the northwest-southeast direction. Tibetan Plateau is the sole cold area with the extremely high temperatures, while the basins located in Northwest China are the warmest areas. ERA-Interim reanalysis data can represent the spatial distribution of extremely low/high-temperature areas in China. The duration of extreme temperatures can be quantitatively analyzed using the quantile function, which provides reference for the quantitative analysis of extreme climate events.
2013(1):1-6.
Abstract:
The instantaneous peak flow (IPF) is the basic information for hydraulic design，construction and management. It also has an important influence on the investment and safety of hydraulic structures. However, the IPF records in Tibet are generally short in length, while mean daily flow (MDF) records are relatively longer. In this study, the IPF records are extended by analyzing the relationship between corresponding IPF and MDF records. The results show that the ratio between IPF and MDF is stable in most of hydrological stations. The relative error between estimated IPF and observed IPF is less than 10%. The results of flood frequency analysis using extended IPF series are more reasonable than that using the measured IPF series. For the stations with limited measured MDF, the HIMS model is used to extend the available MDF. The HIMS model is applied in three representative rivers of Tibet: the Nianchu river, Lhasa river and Niang river. The results show that the model has a good performance in both daily and peak flow simulation. The end year of IPF series in the three representative hydrological stations has been extended from 2000 to 2010 by the simulation results of HIMS and the relationship between IPF and MDF.
The instantaneous peak flow (IPF) is the basic information for hydraulic design，construction and management. It also has an important influence on the investment and safety of hydraulic structures. However, the IPF records in Tibet are generally short in length, while mean daily flow (MDF) records are relatively longer. In this study, the IPF records are extended by analyzing the relationship between corresponding IPF and MDF records. The results show that the ratio between IPF and MDF is stable in most of hydrological stations. The relative error between estimated IPF and observed IPF is less than 10%. The results of flood frequency analysis using extended IPF series are more reasonable than that using the measured IPF series. For the stations with limited measured MDF, the HIMS model is used to extend the available MDF. The HIMS model is applied in three representative rivers of Tibet: the Nianchu river, Lhasa river and Niang river. The results show that the model has a good performance in both daily and peak flow simulation. The end year of IPF series in the three representative hydrological stations has been extended from 2000 to 2010 by the simulation results of HIMS and the relationship between IPF and MDF.
2013(6):144-147.
Abstract:
Environmental Kuznets Curve (EKC) hypothesis has instructive significance to explore the relationship between environmental protection and economic development and to seek the coordinated development of economy and environment. Based on the analysis of the basic conception of EKC hypothesis, the research progress of the impact factors, theoretical developments, and empirical studies of EKC were illustrated in this paper, and the existing problems of the hypothesis were also discussed. Finally, it was noted that under the international trade conditions, the developing countries should study the clean technology, policy reformation, public education, and environmental law system from the developed countries, which can help them decrease the EKC turn point, flatten EKC curve, and seek for win-win relationship between economy and environment.
Environmental Kuznets Curve (EKC) hypothesis has instructive significance to explore the relationship between environmental protection and economic development and to seek the coordinated development of economy and environment. Based on the analysis of the basic conception of EKC hypothesis, the research progress of the impact factors, theoretical developments, and empirical studies of EKC were illustrated in this paper, and the existing problems of the hypothesis were also discussed. Finally, it was noted that under the international trade conditions, the developing countries should study the clean technology, policy reformation, public education, and environmental law system from the developed countries, which can help them decrease the EKC turn point, flatten EKC curve, and seek for win-win relationship between economy and environment.
7 Model evaluation and spatial-temporal variations of potential evapotranspiration in Haihe Catchment
2017, 15(6):11-16.
Abstract:
Based on the observation data of average temperature, sunshine hours, wind speed, and relative humidity at 45 stations in Haihe Catchment during 1960—2012, we compared three potential evapotranspiration models with the Penman—Monteith model. The absolute and relative errors were used as the model evaluation indices. Hargreaves model based on energy balance proved to be the most suitable for potential evapotranspiration estimation in Haihe Catchment. The annual potential evapotranspiration declined at a mean rate of 2.04 mm?a-1 in 1960-2012. The inter-annual variations of potential evapotranspiration in the four seasons all showed a significant decreasing trend, with the largest decline in summer and the smallest decline in winter. Spatially, the average potential evapotranspiration during 1960-2012 tended to increase from the northwest part of the region to the southeast. Moreover, the decrease of potential evapotranspiration occurred in most part of the region, especially in the southeast, which means potential evapotranspiration may be mainly impacted by global dimming. However, potential evapotranspiration in the northwest part of the region showed an increasing trend, probably due to global warming.
Based on the observation data of average temperature, sunshine hours, wind speed, and relative humidity at 45 stations in Haihe Catchment during 1960—2012, we compared three potential evapotranspiration models with the Penman—Monteith model. The absolute and relative errors were used as the model evaluation indices. Hargreaves model based on energy balance proved to be the most suitable for potential evapotranspiration estimation in Haihe Catchment. The annual potential evapotranspiration declined at a mean rate of 2.04 mm?a-1 in 1960-2012. The inter-annual variations of potential evapotranspiration in the four seasons all showed a significant decreasing trend, with the largest decline in summer and the smallest decline in winter. Spatially, the average potential evapotranspiration during 1960-2012 tended to increase from the northwest part of the region to the southeast. Moreover, the decrease of potential evapotranspiration occurred in most part of the region, especially in the southeast, which means potential evapotranspiration may be mainly impacted by global dimming. However, potential evapotranspiration in the northwest part of the region showed an increasing trend, probably due to global warming.
2016, 14(1):1-9.
Abstract:
An index of land use, w ater and habitat qua lity ( ILWH Q) w as pro po sed and applied to evaluat e the env iro nmental qualit y in the st udy area. The least deteriorat ed sites ( ILWH Q [ 2; T 13, T15, T16, T17 and T 18) wer e selected as the reference sites. Five of t he initia l 35 candidate metr ics w ere select ed using a stepw ise pro cedure ( principal component analysis, the analy sis of the range o f index v alue distributio n, stepwise reg ression analysis, Pearso n co rr elation) to evaluate metric stabilit y, r espon2 siv eness to environmental va riables and r edundancy. The selected metrics included the number of Cy pr inidae species ( F5) , the pr opor tion of indiv iduals as bent hic species ( F12) , the pro po rtio n of omniv or e species ( F14) , the pro po rtio n of individuals as tolerant species ( F22) , and the pr opor tion o f demersal egg s species ( F23) . Ratio n scor ing met ho d was employ ed to sco re the five metr ics, and the eco sy stem health of the Huntai Riv er basin defined into fiv e classes. The r esults show ed that fiv e sites wer e in ex cellent co ndition, elev en wer e in go od conditio n, eight in normal condit ion, nine in poor co ndition, and eight in ver y po or co ndition in the T aizi River basin. Ther e w as no site in ex cellent condition, five in go od co ndition, six in no rmal conditio n, six in po or co ndition, and six in ver y poo r conditio n in the H un River basin. T he sites in poo r and v er y poo r co nditions acco unted for 52. 2% o f the total sites in the H un River basin, and 41. 5% o f t he to tal sites in the T aizi Riv er basin. These f inding s indicated that eco sy stem health was w orse in the Hun Riv er than that in the T aizi Riv er.
An index of land use, w ater and habitat qua lity ( ILWH Q) w as pro po sed and applied to evaluat e the env iro nmental qualit y in the st udy area. The least deteriorat ed sites ( ILWH Q [ 2; T 13, T15, T16, T17 and T 18) wer e selected as the reference sites. Five of t he initia l 35 candidate metr ics w ere select ed using a stepw ise pro cedure ( principal component analysis, the analy sis of the range o f index v alue distributio n, stepwise reg ression analysis, Pearso n co rr elation) to evaluate metric stabilit y, r espon2 siv eness to environmental va riables and r edundancy. The selected metrics included the number of Cy pr inidae species ( F5) , the pr opor tion of indiv iduals as bent hic species ( F12) , the pro po rtio n of omniv or e species ( F14) , the pro po rtio n of individuals as tolerant species ( F22) , and the pr opor tion o f demersal egg s species ( F23) . Ratio n scor ing met ho d was employ ed to sco re the five metr ics, and the eco sy stem health of the Huntai Riv er basin defined into fiv e classes. The r esults show ed that fiv e sites wer e in ex cellent co ndition, elev en wer e in go od conditio n, eight in normal condit ion, nine in poor co ndition, and eight in ver y po or co ndition in the T aizi River basin. Ther e w as no site in ex cellent condition, five in go od co ndition, six in no rmal conditio n, six in po or co ndition, and six in ver y poo r conditio n in the H un River basin. T he sites in poo r and v er y poo r co nditions acco unted for 52. 2% o f the total sites in the H un River basin, and 41. 5% o f t he to tal sites in the T aizi Riv er basin. These f inding s indicated that eco sy stem health was w orse in the Hun Riv er than that in the T aizi Riv er.
2014, 12(1):1-6.
Abstract:
Based on the daily data of precipitation and temperature of 30 basic meteorological stations during the period 1956-2010, twelve indices characterizing extreme climate change have been selected to analyze the temporal changes in precipitation and temperature extremes in the Hai River Basin. As per many other parts of the world, the analysis shows an increase in the intensity, frequency and duration of high temperature extremes and a decrease in that of cold extremes. The intensity of short-time precipitation extremes shows an increase and the frequency of heavy precipitation shows a decrease. The consecutive wet days shows a decrease, while the consecutive dry days shows an increase in recent decades, thus the dry pattern has been aggravated in the basin. The annual high temperature extremes and short-time precipitation extremes have begun to frequently occur since 1990s from interdecadal variations, the rainfall of long-duration precipitation events has shown a decrease however. The general warm and dry trend and precipitation concentration will have a negative impact on the agriculture production and water resources development. Meanwhile, the increase of short-time precipitation extremes may exacerbate the risk of local flood disaster in mountainous area as well as urban waterlogging.
Based on the daily data of precipitation and temperature of 30 basic meteorological stations during the period 1956-2010, twelve indices characterizing extreme climate change have been selected to analyze the temporal changes in precipitation and temperature extremes in the Hai River Basin. As per many other parts of the world, the analysis shows an increase in the intensity, frequency and duration of high temperature extremes and a decrease in that of cold extremes. The intensity of short-time precipitation extremes shows an increase and the frequency of heavy precipitation shows a decrease. The consecutive wet days shows a decrease, while the consecutive dry days shows an increase in recent decades, thus the dry pattern has been aggravated in the basin. The annual high temperature extremes and short-time precipitation extremes have begun to frequently occur since 1990s from interdecadal variations, the rainfall of long-duration precipitation events has shown a decrease however. The general warm and dry trend and precipitation concentration will have a negative impact on the agriculture production and water resources development. Meanwhile, the increase of short-time precipitation extremes may exacerbate the risk of local flood disaster in mountainous area as well as urban waterlogging.
10 Flood and Waterlogging Disaster Loss Assessment Based on Meteorological and Hydrological Elements
2014, 12(1):26-31.
Abstract:
The flood and waterlogging disaster loss assessment is a very important component for the disaster relief work, which has important theoretical and practical significance for the research of disaster and its relief. According to the correlation analysis between the flood disaster loss and meteorological and hydrological elements, a correlation model between the area and property of flood disaster loss and historical meteorological and hydrologic factors was developed. The property loss rate and background data of permanent assets were used to evaluate the direct economic losses caused by flood disaster, which are useful for the pre-disaster preliminary assessment and post-disaster rapid assessment. In this paper, the flood of the middle reach of Huaihe River in Anhui Province in 2007 was analyzed, which provided similar assessment results of flood disaster loss with those reported data in reality. Therefore, the evaluation method is applicable and reliable.
The flood and waterlogging disaster loss assessment is a very important component for the disaster relief work, which has important theoretical and practical significance for the research of disaster and its relief. According to the correlation analysis between the flood disaster loss and meteorological and hydrological elements, a correlation model between the area and property of flood disaster loss and historical meteorological and hydrologic factors was developed. The property loss rate and background data of permanent assets were used to evaluate the direct economic losses caused by flood disaster, which are useful for the pre-disaster preliminary assessment and post-disaster rapid assessment. In this paper, the flood of the middle reach of Huaihe River in Anhui Province in 2007 was analyzed, which provided similar assessment results of flood disaster loss with those reported data in reality. Therefore, the evaluation method is applicable and reliable.
2016, 14(1):161-164.
Abstract:
Both spo ng e city and smart city ar e the new generations of concept for urban management to make t he city become bett er . It can help to become intellig ent wit h adding the intellig ent concept o f smart city into the spo nge cit y, which can be o f gr eat signif icance by speeding up the pace to co nstr uct the sponge city and taking advantag e o f the spo ng e cit y mor e efficiently. Firstly, this ar ticle int roduces the intelligent concept o f sponge cit y, and t hen intro duces the applicatio n o f intelligent concept to the sponge city form planning, co nst ruct ion, o per ation manag ement and per formance ev aluation of spong e city in or der to prov ide some refer ence and rev elation for t he develo pment of smar t spo ng e city.
Both spo ng e city and smart city ar e the new generations of concept for urban management to make t he city become bett er . It can help to become intellig ent wit h adding the intellig ent concept o f smart city into the spo nge cit y, which can be o f gr eat signif icance by speeding up the pace to co nstr uct the sponge city and taking advantag e o f the spo ng e cit y mor e efficiently. Firstly, this ar ticle int roduces the intelligent concept o f sponge cit y, and t hen intro duces the applicatio n o f intelligent concept to the sponge city form planning, co nst ruct ion, o per ation manag ement and per formance ev aluation of spong e city in or der to prov ide some refer ence and rev elation for t he develo pment of smar t spo ng e city.
2014, 12(1):154-157.
Abstract:
A proposed water transfer tunnel will be excavated with tunnel boring machine (TBM) in the surrounding type-III rock. The shotcrete and reinforced concrete segment serve as the initial support and permanent liner, respectively. The considerable internal and external water pressures are loaded on the liner, with the water head values of 110 m and 200 m, respectively. In this paper, in consideration of the contact relationship between segments, the contact relationship between segment and surrounding structure, and the cooperative working performance of reinforcement bars and concrete, the stress deformation characteristics of the liner under high water pressures are analyzed using the finite element method. The results showed that the external water pressure is the decisive load for the design of tunnel liner, and therefore a simplified model of segment liner design was proposed. The results suggested that it is feasible to use the reinforced concrete segment as tunnel lining under the conditions of the surrounding rock, support, and water pressure shown in the study.
A proposed water transfer tunnel will be excavated with tunnel boring machine (TBM) in the surrounding type-III rock. The shotcrete and reinforced concrete segment serve as the initial support and permanent liner, respectively. The considerable internal and external water pressures are loaded on the liner, with the water head values of 110 m and 200 m, respectively. In this paper, in consideration of the contact relationship between segments, the contact relationship between segment and surrounding structure, and the cooperative working performance of reinforcement bars and concrete, the stress deformation characteristics of the liner under high water pressures are analyzed using the finite element method. The results showed that the external water pressure is the decisive load for the design of tunnel liner, and therefore a simplified model of segment liner design was proposed. The results suggested that it is feasible to use the reinforced concrete segment as tunnel lining under the conditions of the surrounding rock, support, and water pressure shown in the study.
2014, 12(1):7-11.
Abstract:
The objective of this study is to evaluate the applicability of SWAT model to agricultural drought evaluation for regions without or lack of soil moisture data. For this purpose, the SWAT model was applied to simulate the hydrological process in the Bahe watershed of the upper Weihe River. The soil water content was obtained and it was used to calculate the relative soil moisture. The calculated relative soil moisture was regarded as the evaluation index of agricultural drought. The results showed that severe spring droughts occurred in 2001 and 2002 and summer drought occurred in 2003 in the Bahe watershed, which was in accordance with the actual conditions. . Therefore, SWAT model is applicable to agricultural drought evaluation for the area lack of soil moisture data.
The objective of this study is to evaluate the applicability of SWAT model to agricultural drought evaluation for regions without or lack of soil moisture data. For this purpose, the SWAT model was applied to simulate the hydrological process in the Bahe watershed of the upper Weihe River. The soil water content was obtained and it was used to calculate the relative soil moisture. The calculated relative soil moisture was regarded as the evaluation index of agricultural drought. The results showed that severe spring droughts occurred in 2001 and 2002 and summer drought occurred in 2003 in the Bahe watershed, which was in accordance with the actual conditions. . Therefore, SWAT model is applicable to agricultural drought evaluation for the area lack of soil moisture data.
2014, 12(2):107-110.
Abstract:
Accurate and rapid determination of the distribution of contaminants is the main task for the investigation work of a contaminated site. As a new surveying tool for contaminated sites, direct push technology can be used for soil sample collection in the vadoze zone and aquifer, detection of aquifer parameters, and determination of pollutants. It has the advantages of fast, accurate, and free of cross-contamination. In this paper, the development and research progress of direct push technology was introduced, and the technology innovation was discussed.
Accurate and rapid determination of the distribution of contaminants is the main task for the investigation work of a contaminated site. As a new surveying tool for contaminated sites, direct push technology can be used for soil sample collection in the vadoze zone and aquifer, detection of aquifer parameters, and determination of pollutants. It has the advantages of fast, accurate, and free of cross-contamination. In this paper, the development and research progress of direct push technology was introduced, and the technology innovation was discussed.
2017, 15(2):1-8.
Abstract:
The Middle Route of South to North Water Diversion Project (MRP) has long canals, involves many areas and hydraulic structures, transfers water by a huge amount, and has various working conditions. These all bring great difficulties to the regulation, control, and management of the project. The technical problem of the engineering lies in the fact that the scientific and mechanism problems behind it are not fully revealed and solved, including multi-dimensional equilibrium control mechanism of multiple water sources under changing conditions, multi-process coupling mechanism of water quantity and water quality, emergency scheduling model for multi-material water pollution, hydraulic response mechanism and control of open channel under multi-gate joint application. In order to establish a complete set of technical system to support its scheduling, this paper summarizes the existing research on the five key points of forecast, scheduling, simulation, control, and evaluation. And on the basis of summarizing the previous research, the key technologies awaiting urgent research are explained in detail, including forecast and scheduling in water source areas and water-receiving areas, multi-phase simulation of water pollution, water quality and water quality control, automatic control technology, evaluation technology, and platform construction. Finally, the paper discusses the scientific problems to be solved in order to realize the intelligent regulation and emergency regulation for the MRP and makes a summary of the research.
The Middle Route of South to North Water Diversion Project (MRP) has long canals, involves many areas and hydraulic structures, transfers water by a huge amount, and has various working conditions. These all bring great difficulties to the regulation, control, and management of the project. The technical problem of the engineering lies in the fact that the scientific and mechanism problems behind it are not fully revealed and solved, including multi-dimensional equilibrium control mechanism of multiple water sources under changing conditions, multi-process coupling mechanism of water quantity and water quality, emergency scheduling model for multi-material water pollution, hydraulic response mechanism and control of open channel under multi-gate joint application. In order to establish a complete set of technical system to support its scheduling, this paper summarizes the existing research on the five key points of forecast, scheduling, simulation, control, and evaluation. And on the basis of summarizing the previous research, the key technologies awaiting urgent research are explained in detail, including forecast and scheduling in water source areas and water-receiving areas, multi-phase simulation of water pollution, water quality and water quality control, automatic control technology, evaluation technology, and platform construction. Finally, the paper discusses the scientific problems to be solved in order to realize the intelligent regulation and emergency regulation for the MRP and makes a summary of the research.
2014, 12(1):82-87.
Abstract:
Compared with the traditional determined hydrologic forecast, hydrologic ensemble forecast contains various uncertainties in the hydrologic forecast processes. Therefore, the accuracy and validity of hydrologic forecast have been improved theoretically. Meanwhile, the cognitive and predictive capabilities of the events such as storm, flood, and drought have been enhanced in the practical applications. The hydrologic ensemble forecast can provide more accurate and useful information in flood control, drought relief, and sustainable water resources management. In this paper, we firstly reviewed the history of hydrologic ensemble forecast, and then we summarized the research progresses in theory, methods, as well as the applications and operational hydrologic ensemble forecast. We focused on two research aspects of the pre-processing and post-processing issues in an effort to provide a useful platform for the development of hydrologic ensemble prediction. The perspectives and recommendations on this subject were provided. This paper is of important significance in the future development of hydrologic ensemble forecast research.
Compared with the traditional determined hydrologic forecast, hydrologic ensemble forecast contains various uncertainties in the hydrologic forecast processes. Therefore, the accuracy and validity of hydrologic forecast have been improved theoretically. Meanwhile, the cognitive and predictive capabilities of the events such as storm, flood, and drought have been enhanced in the practical applications. The hydrologic ensemble forecast can provide more accurate and useful information in flood control, drought relief, and sustainable water resources management. In this paper, we firstly reviewed the history of hydrologic ensemble forecast, and then we summarized the research progresses in theory, methods, as well as the applications and operational hydrologic ensemble forecast. We focused on two research aspects of the pre-processing and post-processing issues in an effort to provide a useful platform for the development of hydrologic ensemble prediction. The perspectives and recommendations on this subject were provided. This paper is of important significance in the future development of hydrologic ensemble forecast research.
2017, 15(6):17-25.
Abstract:
The 14-day medium-range precipitation forecast is important for drought and flood forecasting and water resources scheduling management. TIGGE (THORPEX Interactive Grand Global Ensemble) provides basic data for regional medium-range ensemble precipitation prediction. Based on the ensemble forecasts of CMA, CMC, ECMWF, JMA and NCEP in the TIGGE datasets in Jiangsu Province, we evaluated their medium-range precipitation forecast results. We mainly used such evaluation methods as the TS, BS, mean absolute deviation, and mean square root error. The results showed that the forecast scores of light and moderate rain during the entire forecast period were all relatively high. The light rain had the highest TS (mostly around 0.5) statistically. However, there were obvious missing reports of precipitations above the moderate level. For the 15-day forecast of daily cumulative rainfall, there was only a 3-day decay period, after which all the error indicators remained stable. The prediction bias in a lead time of over 3 days was mainly overprediction. Meanwhile, the cumulative rainfall forecast of over 5 days was significantly larger than the actual value. The forecast effect was the best in winter and the worst in summer, and the effect in northern Jiangsu was better than that in southern Jiangsu. Across the five representative modes, the ECMWF and JMA modes respectively showed the best performance in rainfall categorical forecast and daily cumulative rainfall forecast.
The 14-day medium-range precipitation forecast is important for drought and flood forecasting and water resources scheduling management. TIGGE (THORPEX Interactive Grand Global Ensemble) provides basic data for regional medium-range ensemble precipitation prediction. Based on the ensemble forecasts of CMA, CMC, ECMWF, JMA and NCEP in the TIGGE datasets in Jiangsu Province, we evaluated their medium-range precipitation forecast results. We mainly used such evaluation methods as the TS, BS, mean absolute deviation, and mean square root error. The results showed that the forecast scores of light and moderate rain during the entire forecast period were all relatively high. The light rain had the highest TS (mostly around 0.5) statistically. However, there were obvious missing reports of precipitations above the moderate level. For the 15-day forecast of daily cumulative rainfall, there was only a 3-day decay period, after which all the error indicators remained stable. The prediction bias in a lead time of over 3 days was mainly overprediction. Meanwhile, the cumulative rainfall forecast of over 5 days was significantly larger than the actual value. The forecast effect was the best in winter and the worst in summer, and the effect in northern Jiangsu was better than that in southern Jiangsu. Across the five representative modes, the ECMWF and JMA modes respectively showed the best performance in rainfall categorical forecast and daily cumulative rainfall forecast.
LIU Yong-hui
,
TIAN Ye
,
LIU Ao-ran
,
YANG Qing-hua
,
YANG Zhen-jing
,
ZHOU Ya-hong
,
GUO Zhao-xia
,
SUN Li-ming
2014, 12(1):69-72.
Abstract:
Based on the high-resolution sporopollen records of the section in the Yudaokou pasture of Weichang County, Hebei Province, the variations of climate and environment since 6000 a B.P. (14C dating is 5.7ka B.P. at the section bottom) in the Yudaokou area of Weichang County were analyzed. The regional features of sporopollen assemblages showed that the paleoclimate in the Yudaokou area experienced seven stages since 6000 a B. P.: cool and slightly wet - cool and dry- warm and slightly wet –warm and wet – warm and slightly wet –warm and wet - cool and slightly dry. Vegetation landscape was mainly coniferous forest - steppe vegetation, which was dominated with Pinus and Artemisia and scattered with a small amount of Betula, Quercus, and other deciduous trees and shrubs in the forest. The paleoclimate change pattern since the Holocene in the study area is similar to that in other regions of China.
Based on the high-resolution sporopollen records of the section in the Yudaokou pasture of Weichang County, Hebei Province, the variations of climate and environment since 6000 a B.P. (14C dating is 5.7ka B.P. at the section bottom) in the Yudaokou area of Weichang County were analyzed. The regional features of sporopollen assemblages showed that the paleoclimate in the Yudaokou area experienced seven stages since 6000 a B. P.: cool and slightly wet - cool and dry- warm and slightly wet –warm and wet – warm and slightly wet –warm and wet - cool and slightly dry. Vegetation landscape was mainly coniferous forest - steppe vegetation, which was dominated with Pinus and Artemisia and scattered with a small amount of Betula, Quercus, and other deciduous trees and shrubs in the forest. The paleoclimate change pattern since the Holocene in the study area is similar to that in other regions of China.
2013(6):1-4.
Abstract:
Based on the comparative analysis of water resources quantities obtained from China Water Resource Bulletin between 2001 and 2010 and determined by the 45-year results of the second water resources investigation and evaluation, the variation of water resources quantity was analyzed in the last ten years of China. The results suggested that (1) the 45-year results are still representative according to the demonstration of the 45-year natural runoff and its extended results in the first-grade region of water resources; (2) as for the first-grade region of water resources, most area has less water except for Huaihe River Region and Northwestern River Region. The distribution of surface water resources determines the distribution of total water resources; and (3) in the last ten years, climate change and human activities worse the water resources situation in the north, resulting in an extended low flow period. The water resources distribution of less water in the north and much water in the south aggravates.
Based on the comparative analysis of water resources quantities obtained from China Water Resource Bulletin between 2001 and 2010 and determined by the 45-year results of the second water resources investigation and evaluation, the variation of water resources quantity was analyzed in the last ten years of China. The results suggested that (1) the 45-year results are still representative according to the demonstration of the 45-year natural runoff and its extended results in the first-grade region of water resources; (2) as for the first-grade region of water resources, most area has less water except for Huaihe River Region and Northwestern River Region. The distribution of surface water resources determines the distribution of total water resources; and (3) in the last ten years, climate change and human activities worse the water resources situation in the north, resulting in an extended low flow period. The water resources distribution of less water in the north and much water in the south aggravates.
20 Analysis on Characteristics of Tropical Cyclone Rainstorms in Huang-Huai-Hai Area from 1961 to 2010
2014, 12(2):1-5.
Abstract:
Based on the daily rainfall data at 61 stations in the Huang-Huai-Hai area from 1961 to 2010 and the data of《Tropical Cyclone Yearbook》, the frequency and intensity of tropical cyclone and tropical cyclone rainstorm were analyzed using the methods of regression analysis and ArcGIS spatial analysis. The results showed that the tropical cyclone in the Huang-Huai-Hai region usually lands intensely in the coastal place of Zhejiang and Fujian in August with the type of northward class path. Overall, the tropical cyclone rainstorm of the Huang-Huai-Hai area accounts for a small proportion of the total storm, but it has high intensity and the average amount of tropical cyclone rainstorm reaches 93.2 mm, which is similar to the heavy rainstorm. The temporal and spatial distribution of the frequency and amount of tropical cyclone rainstorm are both unbalanced. The frequency and intensity of tropical cyclone rainstorm in the Huang-Huai-Hai region increases in recent years, and the east coast and central and western regions?are most likely influenced by tropical cyclone with high frequency and heavy rainstorm. In addition, the frequency of tropical cyclone rainstorm shows a decreasing trend from east to west on the whole, but the distribution of rainstorm quantity is not apparent.
Based on the daily rainfall data at 61 stations in the Huang-Huai-Hai area from 1961 to 2010 and the data of《Tropical Cyclone Yearbook》, the frequency and intensity of tropical cyclone and tropical cyclone rainstorm were analyzed using the methods of regression analysis and ArcGIS spatial analysis. The results showed that the tropical cyclone in the Huang-Huai-Hai region usually lands intensely in the coastal place of Zhejiang and Fujian in August with the type of northward class path. Overall, the tropical cyclone rainstorm of the Huang-Huai-Hai area accounts for a small proportion of the total storm, but it has high intensity and the average amount of tropical cyclone rainstorm reaches 93.2 mm, which is similar to the heavy rainstorm. The temporal and spatial distribution of the frequency and amount of tropical cyclone rainstorm are both unbalanced. The frequency and intensity of tropical cyclone rainstorm in the Huang-Huai-Hai region increases in recent years, and the east coast and central and western regions?are most likely influenced by tropical cyclone with high frequency and heavy rainstorm. In addition, the frequency of tropical cyclone rainstorm shows a decreasing trend from east to west on the whole, but the distribution of rainstorm quantity is not apparent.
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