Specific Catchment Area （SCA） is defined as the upstream catchment area of a unit contour. As one of the key terrain parameters, it is widely used in the modeling of hydrology, soil erosion and ecological environmen...Specific Catchment Area （SCA） is defined as the upstream catchment area of a unit contour. As one of the key terrain parameters, it is widely used in the modeling of hydrology, soil erosion and ecological environment. However, SCA value changes significantly at different DEM resolutions, which inevitably affect terrain analysis results. SCA can be described as the ratio of Catchment Area （CA） and DEM grid length. In this paper, the scale effect of CA is firstly investigated. With Jiuyuangou Gully, a watershed about 70 km2 in northern Shaanxi Province of China, as the test area, it is found that the impacts of DEM scale on CA are different in spatial distribution. CA value in upslope location becomes bigger with the decrease of the DEM resolution. When the location is close to downstream areas the impact of DEM scale on CA is gradually weakening. The scale effect of CA can be concluded as a mathematic trend of exponential decline. Then, a downscaling model of SCA is put forward by introducing the scale factor and the location factor. The scaling model can realize the conversion of SCA value from a coarse DEM resolution to a finer one at pixel level. Experiment results show that the downscaled SCA was well revised, and consistent with SCA at the target resolution with respect to the statistical indexes, histogram and spatial distribution. With the advantages of no empirical parameters, the scaling model could be considered as a simple and objective model for SCA scaling in a rugged drainage area.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
The Soil Conservation Service Curve Number (SCS-CN) is a well-established loss-rate model to estimate runoff. It combines watershed parameters and climatic factors in one entity curve number (CN). The CN exhibits an i...The Soil Conservation Service Curve Number (SCS-CN) is a well-established loss-rate model to estimate runoff. It combines watershed parameters and climatic factors in one entity curve number (CN). The CN exhibits an inherent seasonality beyond its spatial variability, which cannot be accounted for by the conventional methods. In the present study, an attempt has been made to determine the CN for different months of monsoon season with an objective to evaluate the impact of monthly CN on runoff estimation for Ozat catchment (Gujarat State, India). The standard CN and month wise CN were determined by three procedures, viz, the median, geometric mean and standard asymptotic fit using gauged rainfall and runoff. This study shows that the predictive capability of CN determination methods can be improved by using monthly CN. Refined Willmott’s index (dr) and mean absolute error (MAE) were used to assess and validate the performance of each method. The asymptotic fit CN method with monthly CN resulting dr from 0.46 to 0.49 and MAE from 1.13 mm to 1.18 mm was judged to be more consistent with the existing commonly used CN methods in terms of runoff estimation for the study area.展开更多
为探究不同绿地调控方式对降雨径流的削减作用,以武汉市南湖汇水分区为研究对象,基于暴雨洪水管理模型(storm water management model,SWMM)模拟分析海绵绿地改造措施下的年径流总量控制率、峰值流量及峰现时间的变化规律,揭示蓝绿协同...为探究不同绿地调控方式对降雨径流的削减作用,以武汉市南湖汇水分区为研究对象,基于暴雨洪水管理模型(storm water management model,SWMM)模拟分析海绵绿地改造措施下的年径流总量控制率、峰值流量及峰现时间的变化规律,揭示蓝绿协同视角下城市汇水分区绿地削减雨水径流效应特征。结果显示:城市汇水分区尺度20%~30%的下凹式绿地改造,可实现年径流控制率65%的海绵城市建设目标;不同的海绵绿地改造措施中,复杂下凹绿地(具备蓄水层和下排管)和简单下凹绿地(无蓄水层和下排管)对于单场降雨事件的作用差异不明显,但长历时多场次降雨情况复杂下凹绿地的效果会更加显著。展开更多
基于吐哈盆地与粉河盆地(Powder River Basin)的煤层气地质资料,探讨了两盆地地质构造演化特征,对比分析了两盆地煤阶、煤岩、煤质、含气量及饱和度等物性条件,指出了吐哈盆地与粉河盆地在煤层气含量构成、渗透率及水文地质条件等方面...基于吐哈盆地与粉河盆地(Powder River Basin)的煤层气地质资料,探讨了两盆地地质构造演化特征,对比分析了两盆地煤阶、煤岩、煤质、含气量及饱和度等物性条件,指出了吐哈盆地与粉河盆地在煤层气含量构成、渗透率及水文地质条件等方面的差异。展开更多
基金Key Project of National Natural Science Foundation of China No.40930531 National Youth Science Foun-dation of China No.40901185 Specialized Research Fund for the Doctoral Program of Higher Education No.20093207120008
文摘Specific Catchment Area （SCA） is defined as the upstream catchment area of a unit contour. As one of the key terrain parameters, it is widely used in the modeling of hydrology, soil erosion and ecological environment. However, SCA value changes significantly at different DEM resolutions, which inevitably affect terrain analysis results. SCA can be described as the ratio of Catchment Area （CA） and DEM grid length. In this paper, the scale effect of CA is firstly investigated. With Jiuyuangou Gully, a watershed about 70 km2 in northern Shaanxi Province of China, as the test area, it is found that the impacts of DEM scale on CA are different in spatial distribution. CA value in upslope location becomes bigger with the decrease of the DEM resolution. When the location is close to downstream areas the impact of DEM scale on CA is gradually weakening. The scale effect of CA can be concluded as a mathematic trend of exponential decline. Then, a downscaling model of SCA is put forward by introducing the scale factor and the location factor. The scaling model can realize the conversion of SCA value from a coarse DEM resolution to a finer one at pixel level. Experiment results show that the downscaled SCA was well revised, and consistent with SCA at the target resolution with respect to the statistical indexes, histogram and spatial distribution. With the advantages of no empirical parameters, the scaling model could be considered as a simple and objective model for SCA scaling in a rugged drainage area.
文摘The Soil Conservation Service Curve Number (SCS-CN) is a well-established loss-rate model to estimate runoff. It combines watershed parameters and climatic factors in one entity curve number (CN). The CN exhibits an inherent seasonality beyond its spatial variability, which cannot be accounted for by the conventional methods. In the present study, an attempt has been made to determine the CN for different months of monsoon season with an objective to evaluate the impact of monthly CN on runoff estimation for Ozat catchment (Gujarat State, India). The standard CN and month wise CN were determined by three procedures, viz, the median, geometric mean and standard asymptotic fit using gauged rainfall and runoff. This study shows that the predictive capability of CN determination methods can be improved by using monthly CN. Refined Willmott’s index (dr) and mean absolute error (MAE) were used to assess and validate the performance of each method. The asymptotic fit CN method with monthly CN resulting dr from 0.46 to 0.49 and MAE from 1.13 mm to 1.18 mm was judged to be more consistent with the existing commonly used CN methods in terms of runoff estimation for the study area.
文摘为探究不同绿地调控方式对降雨径流的削减作用,以武汉市南湖汇水分区为研究对象,基于暴雨洪水管理模型(storm water management model,SWMM)模拟分析海绵绿地改造措施下的年径流总量控制率、峰值流量及峰现时间的变化规律,揭示蓝绿协同视角下城市汇水分区绿地削减雨水径流效应特征。结果显示:城市汇水分区尺度20%~30%的下凹式绿地改造,可实现年径流控制率65%的海绵城市建设目标;不同的海绵绿地改造措施中,复杂下凹绿地(具备蓄水层和下排管)和简单下凹绿地(无蓄水层和下排管)对于单场降雨事件的作用差异不明显,但长历时多场次降雨情况复杂下凹绿地的效果会更加显著。
