基于ArcGis的四川省中小流域设计洪水计算

The Design Flood Calculation of Small and Middle-sized Basin in Sichuan Province Based on ArcGis

综合瞬时单位线的汇流参数是依据单站水文资料以分区综合的方式计算得到。在无资料地区,使用该法推求设计洪水时,可能出现汇流参数地区局部异常的情况,造成设计成果有偏差较大,引起工程不必要的浪费。针对上述情况,本文提出了以ArcGis为平台,借助工程区域DEM数据,建立地貌瞬时单位线的方法来推求设计洪水,用以减小水文模型对于水文资料的依赖。最后,运用该方法推求琼江上游拦江流域设计洪水。设计成果与水科院推理公式法结果进行对比。对比结果表明,该法的计算结果基本合理。同时,参数敏感性分析结果表明设计人员使用该法推求设计洪水时,需要对于设计流域的物理特征有一定的了解。此次实践结果显示,该方法简单易行,容易被设计人员掌握,可以应用于生产实践之中。

The conflux parameters of integrated instantaneous unit hydrograph （IUH） are determined in different sections based on the data of hydrological station.Using this method to calculate the design flood may cause huge errors and unnecessary waste on projects in ungauged areas,due to the exceptional of local conflux parameters.Based on this problem,ArcGis is taken as hydrologic analysis platform,the geomorphological instantaneous unit hydrograph （GIUH） is built by analyzing the DEM data of project areas,which can reduce the needs of hydrologic data.Finally,this method is applied to calculate the design flood of Lanjiang watershed in Qiongjiang upper reach.The result is compared with the rational formula＇s,which shows the design achievement with this method is reasonable.Meantime,parameter sensitivity analysis results show that the design staff needs to grasp the basic physic characteristic of target watershed before using this method to calculate the design flood.Through this practice,this method can be used for the real design work,due to its easy implementation and mastery.