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
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
汇水区是分布式水文地表积涝模拟的基本单元,汇水区划分的精确性对暴雨积涝模拟具有重要意义。利用水文分析工具进行研究区汇水区提取时,由于DEM栅格单元大小不同,汇水区划分空间分布精确性不同。为了研究DEM栅格单元大小对汇水区划分...汇水区是分布式水文地表积涝模拟的基本单元,汇水区划分的精确性对暴雨积涝模拟具有重要意义。利用水文分析工具进行研究区汇水区提取时,由于DEM栅格单元大小不同,汇水区划分空间分布精确性不同。为了研究DEM栅格单元大小对汇水区划分精度的影响规律,本文采用栅格单元大小为30、50、100 m DEM对同一地区进行汇水区划分计算,研究分析DEM栅格单元大小对汇水区划分涉及到的水流方向提取计算、汇流累积量计算、水流长度计算以及对流域分割计算的影响,从而实现DEM栅格单元大小对汇水区划分精度的影响评价。研究发现:栅格单元大小改变,对水流长度计算、流域分割、汇水区划分几个要素影响程度较大,栅格单元大小的变化对流向分析、汇水量提取几个要素的影响程度相对较小。栅格单元变大时,汇水区的面积减小,汇水区的个数也相应的减少;栅格单元变小时,汇水区的面积变大,汇水区的个数也相应增加。展开更多
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.
文摘汇水区是分布式水文地表积涝模拟的基本单元,汇水区划分的精确性对暴雨积涝模拟具有重要意义。利用水文分析工具进行研究区汇水区提取时,由于DEM栅格单元大小不同,汇水区划分空间分布精确性不同。为了研究DEM栅格单元大小对汇水区划分精度的影响规律,本文采用栅格单元大小为30、50、100 m DEM对同一地区进行汇水区划分计算,研究分析DEM栅格单元大小对汇水区划分涉及到的水流方向提取计算、汇流累积量计算、水流长度计算以及对流域分割计算的影响,从而实现DEM栅格单元大小对汇水区划分精度的影响评价。研究发现:栅格单元大小改变,对水流长度计算、流域分割、汇水区划分几个要素影响程度较大,栅格单元大小的变化对流向分析、汇水量提取几个要素的影响程度相对较小。栅格单元变大时,汇水区的面积减小,汇水区的个数也相应的减少;栅格单元变小时,汇水区的面积变大,汇水区的个数也相应增加。
