The relationships between the water qualities of nitrogen and phosphorous contents in the discharge water and the discharge of storm runoff of an experimental catchment including terraced paddy field are analyzed base...The relationships between the water qualities of nitrogen and phosphorous contents in the discharge water and the discharge of storm runoff of an experimental catchment including terraced paddy field are analyzed based on experiment results of the catchment. By summarizing the currently related research on water quality models, the water quality models of different components of storm runoff of the catchment are presented and verified with the experiment data of water quality analyses and the corresponding discharge of the storm runoffs during 3 storms. Through estimating the specific discharge of storm runoff, the specific load of different components of nitrogen and phosphorus in the discharge water of the catchment can be forecasted by the models. It is found that the mathematical methods of linear regression are very useful for analysis of the relationship between the concentrations of nitrogen and phosphorus and the water discharge of storm runoff. It is also found that the most content of the nitrogen (75%) in the discharge water is organic, while half of the content (49%) of phosphorus in the discharge water is inorganic.展开更多
The catchment of runoff which improves the moisture content condition in tree holes isof great improtance to the development of the afforestation in arid and semi-arid regions.The crux of this technique is the soil wa...The catchment of runoff which improves the moisture content condition in tree holes isof great improtance to the development of the afforestation in arid and semi-arid regions.The crux of this technique is the soil water content which influnences the survial rates,展开更多
In this paper, a novel and efficient study on the hydrological processes of storm runoff from catchments of different land uses is conducted. The motivation is to precisely simulate the hydrological processes of storm...In this paper, a novel and efficient study on the hydrological processes of storm runoff from catchments of different land uses is conducted. The motivation is to precisely simulate the hydrological processes of storm runoff in the agricultural catchments with different patterns of land uses, i.e., forest, paddy, and upland, respectively. As it is discussed in this paper, different land use leads to different characteristics of storm runoff. In order to understand the changes in the hydrological processes of storm runoff from catchments of different land uses, the effects of rainfall intensity, initial soil moisture deficit, evapotranspiration rate, percolation rate, and retention capacity on hydrological processes of the catchments are taken into consideration. According to the principle of water balance, a general model to connect the separate hydrological processes is developed; then, the individual hydrological process is studied in detail： Firstly, the daily evaporation is calculated according to the relation between the actual evapotranspiration and the potential evapotranspiration rate; Secondly, the retention of storm runoff is plotted against the total rainfall, and the maximum storage is calculated; Thirdly, the percolation rate is calculated for each catchment.展开更多
Soil hydraulic parameters θs,α,n,Ks,L and θr of the van Genuchten-Mualem model were estimated using three pedotransfer functions(PTFs) based on soil properties for surface soils of the largest main tributary catchm...Soil hydraulic parameters θs,α,n,Ks,L and θr of the van Genuchten-Mualem model were estimated using three pedotransfer functions(PTFs) based on soil properties for surface soils of the largest main tributary catchment(the Jialing River) of the upper Yangtze River in China.The soil database was from the second national soil survey of China with a spatial 30 × 30 arc-second resolution.According to the statistical analysis of the differences between the continuous-PTFs-estimated values of soil hydraulic parameters for the study catchment and the reference values for a specific texture class provided in the development database of a specific PTF,best estimations were obtained using the W?sten PTF.The Rawls & Brakenssiek PTF was good estimation for parameter θr that was assumed as zero by W?sten PTF.The established higher θr(0.08%) and lower Ks(20 cm/d) and θs(0.43%) in the mid-downstream area relative to the other areas of the catchment could lead to larger amounts of surface runoff andconsequently provide higher energy to erode soil.Thus,these factors provide a supporting explanation for previously reported severe soil erosion occurring in this area.Spatial heterogeneity analysis for estimated hydraulic parameters in terms of semivariogram showed that the spatial correlation distance was in the range of 50-80 km and that the spatial variability(sill) was not large except for parameters Ks and L.The semi-variance with the exponential model at the zero distance(nugget) was 30%-50% of the sill.This study provided a practical PTF approach for estimating soil hydraulic properties from soil survey data at a large watershed scale.The estimation results could provide better insight into the mechanism of surface runoff and soil erosion,which is important to better understand and manage erosion in the catchment.展开更多
Among the most basic challenges of hydrology are the prediction and quantification of catchment surface runoff. The runoff curve number （CN） is a key factor in determining runoff in the SCS （Soil Conservation Serv...Among the most basic challenges of hydrology are the prediction and quantification of catchment surface runoff. The runoff curve number （CN） is a key factor in determining runoff in the SCS （Soil Conservation Service） based hydrologic modeling method. The traditional SCS-CN method for calculating the composite curve number is very tedious and consumes a major portion of the hydrologic modeling time. Therefore, geographic information systems （G/S） are now being used in combination with the SCS-CN method. This paper assesses the modeling of flow in West Bank catchments using the GIS-based SCS-CN method. The West Bank, Palestine, is characterized as an arid to semi-arid region with annual rainfall depths ranging between 100 mm in the vicinity of the Jordan River to 700 mm in the mountains extending across the central parts of the region. The estimated composite curve number for the entire West Bank is about 50 assuming dry conditions. This paper clearly demonstrates that the integration of GIS with the SCS-CN method provides a powerful tool for estimating runoff volumes in West Bank catchments, representing arid to semi-arid catchments of Palestine.展开更多
Simulation and modeling the stream flow provide major data while it is a challenge in mountainous basins with regard to the important role of snowmelt runoff as well as the data scarcity in these places. The main purp...Simulation and modeling the stream flow provide major data while it is a challenge in mountainous basins with regard to the important role of snowmelt runoff as well as the data scarcity in these places. The main purpose of this paper is to examine the capability of an integrated application of remote sensing data and Snowmelt Runoff Model (SRM) to simulate scheme of daily stream flow in the snow-dominated catchment, located in the North-East region of Iran. The main parameters of the model are Snow Cover Area (SCA), temperature and participation. Regarding to the lack of measured data, the input variable and parameters of the model are extracted or estimated based on accessible maps, satellite data and available meteorological and hydrological stations. The changes of snow-cover, as spatial-temporal data, which are the most effective variable in performance of SRM, are obtained from the Moderate Resolution Imaging Spectroradiometer (MODIS) eight-day composite snow cover images. The evaluation of the model application efficiency was tested by the coefficient of determination and the volume difference, which are 0.85% and -4.6% respectively. The result depicts the relative capability of SRM though it is evident that the more accurate the estimation of model parameters, the more efficient simulation results can be obtained.展开更多
元江—红河流域水文过程受山地气候和人类活动影响,时空分异性明显;近半个世纪以来,其河川径流变化日趋复杂,跨境水安全风险日益凸显.基于流域55a逐月径流、降水和气温站点数据,利用GAMLSS(Generalized Additive Models for Location,Sc...元江—红河流域水文过程受山地气候和人类活动影响,时空分异性明显;近半个世纪以来,其河川径流变化日趋复杂,跨境水安全风险日益凸显.基于流域55a逐月径流、降水和气温站点数据,利用GAMLSS(Generalized Additive Models for Location,Scale and Shape)建立以时间、气候因子为协变量的时变矩模型,系统分析了综合环境影响下径流序列的非一致性规律及其对气候变化的响应;在非一致性框架下基于重现期的期望超过次数法(Expected Number of Exceedances,ENE)推求设计年径流,探讨了非一致性对流域水资源利用与管理的潜在影响.结果表明:(1)流域径流具有显著非一致性特征,以哀牢山系为界,以东的干游元江倾向于突变性且存在一个位于2002年的显著突变点,以西的支流李仙江在1986年转折点后的局部趋势呈现显著下降;(2)气候因子为协变量的GAMLSS模型分别服从伽马和对数正态分布时,为径流序列提供了最佳拟合,可有效地捕捉气候变化对元江和李仙江径流的影响;(3)与传统一致性模型相比,时变矩模型为计算变化环境下的设计年径流提供了更科学的方法.在选定的排放情景下,基于时变矩模型得到的元江和李仙江设计年径流值较一致性模型,分别表现为-15.12~25.46%和-17.29~22.24%的差异变化,这些差异对水资源开发规模、动态管理和利用过程具有重大影响.研究成果可为元江—红河流域跨境水资源的合理利用与协调管理提供新的科学依据.展开更多
基于SWMM(Storm Water Management Model)对歙县古关组团的暴雨径流过程进行系统分析,揭示了坡度较大的小汇水区域在暴雨初期的显著冲刷效应。研究发现,在1~10 a重现期的暴雨事件中,初雨径流(占总径流的20%)所携带的以总悬浮固体(TSS)...基于SWMM(Storm Water Management Model)对歙县古关组团的暴雨径流过程进行系统分析,揭示了坡度较大的小汇水区域在暴雨初期的显著冲刷效应。研究发现,在1~10 a重现期的暴雨事件中,初雨径流(占总径流的20%)所携带的以总悬浮固体(TSS)计的污染物占比高达44.5%~83.9%,表明该区域存在明显的初雨冲刷现象。进一步分析表明,当采用容积为5 a一遇暴雨,20%初雨径流量的滞留池时,各重现期TSS的拦截率可达到67.4%~78.7%,拦截效果较为理想。该结论为类似坡度较大的小汇水区域末端滞留池的设计与建设提供了科学依据,可有效减少城市的面源污染。展开更多
文摘The relationships between the water qualities of nitrogen and phosphorous contents in the discharge water and the discharge of storm runoff of an experimental catchment including terraced paddy field are analyzed based on experiment results of the catchment. By summarizing the currently related research on water quality models, the water quality models of different components of storm runoff of the catchment are presented and verified with the experiment data of water quality analyses and the corresponding discharge of the storm runoffs during 3 storms. Through estimating the specific discharge of storm runoff, the specific load of different components of nitrogen and phosphorus in the discharge water of the catchment can be forecasted by the models. It is found that the mathematical methods of linear regression are very useful for analysis of the relationship between the concentrations of nitrogen and phosphorus and the water discharge of storm runoff. It is also found that the most content of the nitrogen (75%) in the discharge water is organic, while half of the content (49%) of phosphorus in the discharge water is inorganic.
文摘The catchment of runoff which improves the moisture content condition in tree holes isof great improtance to the development of the afforestation in arid and semi-arid regions.The crux of this technique is the soil water content which influnences the survial rates,
基金Supported by the Natural Science Foundation of Hubei Province (2005ABA290)
文摘In this paper, a novel and efficient study on the hydrological processes of storm runoff from catchments of different land uses is conducted. The motivation is to precisely simulate the hydrological processes of storm runoff in the agricultural catchments with different patterns of land uses, i.e., forest, paddy, and upland, respectively. As it is discussed in this paper, different land use leads to different characteristics of storm runoff. In order to understand the changes in the hydrological processes of storm runoff from catchments of different land uses, the effects of rainfall intensity, initial soil moisture deficit, evapotranspiration rate, percolation rate, and retention capacity on hydrological processes of the catchments are taken into consideration. According to the principle of water balance, a general model to connect the separate hydrological processes is developed; then, the individual hydrological process is studied in detail： Firstly, the daily evaporation is calculated according to the relation between the actual evapotranspiration and the potential evapotranspiration rate; Secondly, the retention of storm runoff is plotted against the total rainfall, and the maximum storage is calculated; Thirdly, the percolation rate is calculated for each catchment.
基金supported by the“Hundred Talents Program”of the Chinese Academy of Sciences and Sichuan Province,the National Basic Research Program of the Ministry of Science and Technology of China(Grant No.2012CB417101)the National Natural Science Foundation of China(Grant Nos.41171372 and 41471268)the CASSAFEA International Partnership Program for Creative Research Team(Grant No.KZZD-EWTZ06)
文摘Soil hydraulic parameters θs,α,n,Ks,L and θr of the van Genuchten-Mualem model were estimated using three pedotransfer functions(PTFs) based on soil properties for surface soils of the largest main tributary catchment(the Jialing River) of the upper Yangtze River in China.The soil database was from the second national soil survey of China with a spatial 30 × 30 arc-second resolution.According to the statistical analysis of the differences between the continuous-PTFs-estimated values of soil hydraulic parameters for the study catchment and the reference values for a specific texture class provided in the development database of a specific PTF,best estimations were obtained using the W?sten PTF.The Rawls & Brakenssiek PTF was good estimation for parameter θr that was assumed as zero by W?sten PTF.The established higher θr(0.08%) and lower Ks(20 cm/d) and θs(0.43%) in the mid-downstream area relative to the other areas of the catchment could lead to larger amounts of surface runoff andconsequently provide higher energy to erode soil.Thus,these factors provide a supporting explanation for previously reported severe soil erosion occurring in this area.Spatial heterogeneity analysis for estimated hydraulic parameters in terms of semivariogram showed that the spatial correlation distance was in the range of 50-80 km and that the spatial variability(sill) was not large except for parameters Ks and L.The semi-variance with the exponential model at the zero distance(nugget) was 30%-50% of the sill.This study provided a practical PTF approach for estimating soil hydraulic properties from soil survey data at a large watershed scale.The estimation results could provide better insight into the mechanism of surface runoff and soil erosion,which is important to better understand and manage erosion in the catchment.
基金supported by the GLOWA-JR Project of the German Federal Ministry of Education and Research (BMBF)
文摘Among the most basic challenges of hydrology are the prediction and quantification of catchment surface runoff. The runoff curve number （CN） is a key factor in determining runoff in the SCS （Soil Conservation Service） based hydrologic modeling method. The traditional SCS-CN method for calculating the composite curve number is very tedious and consumes a major portion of the hydrologic modeling time. Therefore, geographic information systems （G/S） are now being used in combination with the SCS-CN method. This paper assesses the modeling of flow in West Bank catchments using the GIS-based SCS-CN method. The West Bank, Palestine, is characterized as an arid to semi-arid region with annual rainfall depths ranging between 100 mm in the vicinity of the Jordan River to 700 mm in the mountains extending across the central parts of the region. The estimated composite curve number for the entire West Bank is about 50 assuming dry conditions. This paper clearly demonstrates that the integration of GIS with the SCS-CN method provides a powerful tool for estimating runoff volumes in West Bank catchments, representing arid to semi-arid catchments of Palestine.
文摘Simulation and modeling the stream flow provide major data while it is a challenge in mountainous basins with regard to the important role of snowmelt runoff as well as the data scarcity in these places. The main purpose of this paper is to examine the capability of an integrated application of remote sensing data and Snowmelt Runoff Model (SRM) to simulate scheme of daily stream flow in the snow-dominated catchment, located in the North-East region of Iran. The main parameters of the model are Snow Cover Area (SCA), temperature and participation. Regarding to the lack of measured data, the input variable and parameters of the model are extracted or estimated based on accessible maps, satellite data and available meteorological and hydrological stations. The changes of snow-cover, as spatial-temporal data, which are the most effective variable in performance of SRM, are obtained from the Moderate Resolution Imaging Spectroradiometer (MODIS) eight-day composite snow cover images. The evaluation of the model application efficiency was tested by the coefficient of determination and the volume difference, which are 0.85% and -4.6% respectively. The result depicts the relative capability of SRM though it is evident that the more accurate the estimation of model parameters, the more efficient simulation results can be obtained.
文摘元江—红河流域水文过程受山地气候和人类活动影响,时空分异性明显;近半个世纪以来,其河川径流变化日趋复杂,跨境水安全风险日益凸显.基于流域55a逐月径流、降水和气温站点数据,利用GAMLSS(Generalized Additive Models for Location,Scale and Shape)建立以时间、气候因子为协变量的时变矩模型,系统分析了综合环境影响下径流序列的非一致性规律及其对气候变化的响应;在非一致性框架下基于重现期的期望超过次数法(Expected Number of Exceedances,ENE)推求设计年径流,探讨了非一致性对流域水资源利用与管理的潜在影响.结果表明:(1)流域径流具有显著非一致性特征,以哀牢山系为界,以东的干游元江倾向于突变性且存在一个位于2002年的显著突变点,以西的支流李仙江在1986年转折点后的局部趋势呈现显著下降;(2)气候因子为协变量的GAMLSS模型分别服从伽马和对数正态分布时,为径流序列提供了最佳拟合,可有效地捕捉气候变化对元江和李仙江径流的影响;(3)与传统一致性模型相比,时变矩模型为计算变化环境下的设计年径流提供了更科学的方法.在选定的排放情景下,基于时变矩模型得到的元江和李仙江设计年径流值较一致性模型,分别表现为-15.12~25.46%和-17.29~22.24%的差异变化,这些差异对水资源开发规模、动态管理和利用过程具有重大影响.研究成果可为元江—红河流域跨境水资源的合理利用与协调管理提供新的科学依据.
