为了解决由降雨强度引起的径流汇流的非线性问题,提出一种基于SCS(United States Department of Agriculture-Soil Conservation Service)流速公式的时变分布式单位线计算方法。引入参考雨强表征SCS公式中流速系数对应的水力条件。由降...为了解决由降雨强度引起的径流汇流的非线性问题,提出一种基于SCS(United States Department of Agriculture-Soil Conservation Service)流速公式的时变分布式单位线计算方法。引入参考雨强表征SCS公式中流速系数对应的水力条件。由降雨过程的时段雨强与参考雨强的比值构成一个量纲一因子,将该因子加入SCS公式后使其能够考虑降雨对流速的影响。改进后的流速公式用于计算一次降雨过程中不同降雨时段对应的时变分布式单位线,时变分布式单位线与新安江模型的产流模块构成降雨径流模型,将模型用于裴河流域率定参考雨强。率定后的模型用于谭家河流域进行应用检验,结果显示,确定性系数大于等于0.9的洪水场次,由时不变单位线的42%增大为83%。提出的方法能够显著提高流域水文模型的降雨径流模拟能力。展开更多
Rainfall-runoff relationship in arid regions is unique and challenging to study.Studies for bridging the hydro-meteorological knowledge gap for planning,designing and managing water resources is therefore vitally impo...Rainfall-runoff relationship in arid regions is unique and challenging to study.Studies for bridging the hydro-meteorological knowledge gap for planning,designing and managing water resources is therefore vitally important.The objective of this study is to develop a method for estimating unit hydrograph at reasonably finer time resolutions(10-min and 1-h)which can be easily adaptable by practitioners at subcatchment levels,especially when the focus area is ungauged.Observed wadi-flow at 5-min interval and tipping bucket rainfall measurements at 1-min interval were obtained to cover 10 major watersheds in Oman.The deconvolution method was applied to derive the unit hydrographs(UHs)from wadi-flow and excess rainfall.Key catchment characteristics such as the watershed area,length of the main wadi and the length to the centroid of the catchment area were derived from digital elevation model(DEM)data.The whole study area was then divided into 515 sub-catchments with various shapes and sizes.A strong relationship was found between the wadi length and the length to the centroid of the catchment area(R2>0.89).This relationship was then adopted to simplify the classical Snyder method to determine UHs.Moreover,several parameters of the Snyder method were calibrated to the arid environment by matching the peak-flow,lag-time and three time-widths(75%,50%and 30%of the peak-flow)of 10-min and 1-h UHs with physical characteristics of the watersheds.All developed relationships were validated with independent rainfall and wadi-flow events.Results indicate that the calibrated parameters in these arid watersheds are quite distinct from those suggested for other regions of the world.A marked difference was found between the 10-min UHs estimated by the S-hydrograph method and the deconvolution method.Therefore,it is concluded that a method depends on natural hydro-meteorological conditions would be more practical in arid region.The proposed methodology can be used for water resources management in arid regions having similar climate and geographical settings.展开更多
文摘为了解决由降雨强度引起的径流汇流的非线性问题,提出一种基于SCS(United States Department of Agriculture-Soil Conservation Service)流速公式的时变分布式单位线计算方法。引入参考雨强表征SCS公式中流速系数对应的水力条件。由降雨过程的时段雨强与参考雨强的比值构成一个量纲一因子,将该因子加入SCS公式后使其能够考虑降雨对流速的影响。改进后的流速公式用于计算一次降雨过程中不同降雨时段对应的时变分布式单位线,时变分布式单位线与新安江模型的产流模块构成降雨径流模型,将模型用于裴河流域率定参考雨强。率定后的模型用于谭家河流域进行应用检验,结果显示,确定性系数大于等于0.9的洪水场次,由时不变单位线的42%增大为83%。提出的方法能够显著提高流域水文模型的降雨径流模拟能力。
文摘Rainfall-runoff relationship in arid regions is unique and challenging to study.Studies for bridging the hydro-meteorological knowledge gap for planning,designing and managing water resources is therefore vitally important.The objective of this study is to develop a method for estimating unit hydrograph at reasonably finer time resolutions(10-min and 1-h)which can be easily adaptable by practitioners at subcatchment levels,especially when the focus area is ungauged.Observed wadi-flow at 5-min interval and tipping bucket rainfall measurements at 1-min interval were obtained to cover 10 major watersheds in Oman.The deconvolution method was applied to derive the unit hydrographs(UHs)from wadi-flow and excess rainfall.Key catchment characteristics such as the watershed area,length of the main wadi and the length to the centroid of the catchment area were derived from digital elevation model(DEM)data.The whole study area was then divided into 515 sub-catchments with various shapes and sizes.A strong relationship was found between the wadi length and the length to the centroid of the catchment area(R2>0.89).This relationship was then adopted to simplify the classical Snyder method to determine UHs.Moreover,several parameters of the Snyder method were calibrated to the arid environment by matching the peak-flow,lag-time and three time-widths(75%,50%and 30%of the peak-flow)of 10-min and 1-h UHs with physical characteristics of the watersheds.All developed relationships were validated with independent rainfall and wadi-flow events.Results indicate that the calibrated parameters in these arid watersheds are quite distinct from those suggested for other regions of the world.A marked difference was found between the 10-min UHs estimated by the S-hydrograph method and the deconvolution method.Therefore,it is concluded that a method depends on natural hydro-meteorological conditions would be more practical in arid region.The proposed methodology can be used for water resources management in arid regions having similar climate and geographical settings.
