DEM分辨率对小流域设计洪峰推求误差的影响  

Influences of DEM resolution on error of design peak flow in small watershed

作　　者：董晓华[1,2] 杨芝辰 成洁 时磊 刘冀 唐慧雅[1,2] 郭梁锋 赵乔 李国翔 DONG Xiaohua;YANG Zhichen;CHENG Jie;SHI Lei;LIU Ji;TANG Huiya;GUO Liangfeng;ZHAO Qiao;LI Guoxiang(Institute of Water Conservancy and Environment,China Three Gorges University,Yichang 443002,China;Hubei Provincial Collaborative Innovation Center for Water Security,Wuhan University,Wuhan 430070,China;Shenzhen Water Planning and Design Institute Co.Ltd,Shenzhen 518001,China)

机构地区：[1]三峡大学水利与环境学院,湖北宜昌443002 [2]武汉大学水资源安全保障湖北省协同创新中心,湖北武汉430070 [3]深圳市水务规划设计院有限公司,深圳518001

出　　处：《人民长江》2018年第6期8-12,共5页Yangtze River

基　　金：水利部"十二五"公益性行业专项经费项目(201301066);国家自然科学基金项目(40701024;41101511)

摘　　要：推理公式法在小流域设计洪水的计算中被广泛应用,DEM数据分辨率对公式中的流域地形参数取值存在重要影响,甚至会造成设计洪峰流量的计算误差。以深圳石岩流域作为研究区域,分别采用分辨率为30,60,90,120,150 m的DEM数据进行流域地形参数的提取及比较分析,并针对推理公式中的3个流域地形参数进行敏感性分析。研究结果表明:随着DEM分辨率的增大,分析的流域面积有增大趋势,主河道坡降则反之,而干流河长随DEM分辨率呈无规律变化;3个流域地形参数中,流域面积取值误差对设计洪峰计算精度影响最大,其次为干流河长,主河道坡降影响较小。综合考虑参数重要性,以及DEM数据分辨率及集水面积阈值对参数取值的影响,选用90 m分辨率的DEM数据,并设置集水面积阈值为390~500 hm^2来提取石岩流域的地形参数,推理公式计算所得设计洪峰误差是可接受的。研究结果可为类似的小流域设计洪水计算提供一定参考。The rational formula is widely applied in the calculation of the design flood in small watershed and the DEM resolution has important influence on topographic parameters in the formula,which may even cause some errors in the calculation of design peak flow.This paper takes Shiyan river basin in Shenzhen as the study area,and DEM data at resolutions of 30,60,90,120 m and 150 m are used for extraction and comparative analysis of topographic parameters,then sensitivity analysis for three terrain parameters in the rational formula are carried out.The results show that with the increase of DEM resolution,the calculated basin area increases,and the slope of the main river channel decreases,while the length of the mainstream varies irregularly;among the three topographic parameters,the error of the basin area has the greatest influence on the calculation of flood peak,followed by the length of the mainstream,and the slope of the main channel has less effects.Considering the importance of different parameters,as well as the influence of DEM resolution and catchment area threshold on the parameters,90 m DEM and catchment area threshold of 390~500 hm 2 is reasonable to extract basin terrain parameters and the calculation error for the design flood peak is acceptable,which provides a reference to design flood calculation for similar watershed.

关 键 词：推理公式法 设计洪峰 地形参数 DEM分辨率 参数敏感性 石岩水库流域 深圳 

分 类 号：P33[天文地球—水文科学]