快速城市化地区多尺度水文观测试验与暴雨洪水响应机理分析  

Multi-scale hydrological experimental observations and responding mechanisms of storm floods in rapid urbanization areas

作　　者：王强[1] 许有鹏[1] 于志慧[1] 林芷欣 高斌[1] WANG Qiang;XU Youpeng;YU Zhihui;LIN Zhixin;GAO Bin(School of Geography and Ocean Science,Nanjing University,Nanjing 210023,China)

机构地区：[1]南京大学地理与海洋科学学院,江苏南京210023

出　　处：《水科学进展》2022年第5期743-753,共11页Advances in Water Science

基　　金：国家自然科学基金资助项目(42101020,U2240203)。

摘　　要：城市下垫面改变引起水文循环过程发生变异,导致目前已掌握的天然情况下的产汇流规律和机制难以解释城市化等新形势下的水文现象与过程,而面临需重新再认识的挑战。本文以长三角地区为典型,建立了不同城市化水平及空间规模的水文试验流域,探讨了快速城市化地区暴雨洪水响应规律和机制。结果表明:(1)不同量级降水事件下城镇用地土壤水响应程度(表层土壤水涨幅基本超过4%)总体高于其他土地利用类型,城市化地区下垫面的改变通过影响土壤水动态响应模式直接影响了地表产流过程,植被覆盖率较低的城镇用地和荒地土壤含水率呈现出陡涨陡落现象,而植被作用下的土地利用类型则表现出缓慢上升和缓慢消退的土壤水响应过程。(2)流域洪峰滞时和洪峰流量整体表现为随流域面积增加而呈幂律函数关系形式的增加。(3)总降水量与主要洪水特征(如洪峰流量、单位面积洪峰流量和径流深)基本呈显著相关(相关系数分别达0.49、0.41和0.78以上)。城市下垫面通过改变土壤水动态响应等产汇流特征而直接影响了洪水过程,未来长三角地区暴雨洪水在城市化和气候因素双重作用下呈现持续加剧的趋势。Rapid urbanization processes alter the regional underlying surface,leading to changes in the hydrological cycle.Such changes have made it difficult to explain the traditional water yielding and runoff routing mechanism,which necessitates our new exploration.In this paper,taking the Yangtze River Delta region as an example,we have conducted the experimental observations in basins with the different urbanization levels and different space scales.Via the collected first-hand hydrologic data,namely,rainfall,soil moisture,and streamflow with high resolutions(5 min time intervals),we adopted data-driven flood feature analysis to reveal the responses of the flood characteristics,such as flood lag time and peak discharge.Then,we discussed the response mechanism of rainstorm and flood in rapid urbanization areas.The main conclusions are as follows:(1)Compared with other land use/cover types,the response of soil moisture for urban land are more intense under different rainstorm events(usually increasing more than 4%for the surface layer).The change of underlying surface in urbanized area affects the processes of surface runoff by influencing the dynamics of soil moisture.The soil moisture content of urban land and wasteland with low vegetation coverage showed steep rise and fall with the beginning and end of rainfall,while that of land use with higher coverage showed slow rise and decline trends.(2)Flood peak lag time and peak discharge are mainly controlled by watershed scale.There have power law relationships between flood lag time and peak flow with watershed scale,and factors such as impervious surface and topography also have some influences on flood characteristics.(3)Rainstorm is a direct driving factor of flood in the Yangtze River Delta region.Rainfall characteristics are strongly correlated with the peak discharge,peak discharge per unit area,and runoff depth,with correlation coefficients above 0.49,0.41 and 0.78,respectively.In general,the natural geographical characteristics and rainfall are the main factors af

关 键 词：城市化 暴雨洪水 响应规律 多尺度观测试验 长三角地区 

分 类 号：P332[天文地球—水文科学]