城镇化对径流的长期影响研究

A Research of Long-term Impact on Runoff in Urbanized Areas

由于城镇化水平的提高,地表状况的改变,不透水面积的增加,对径流的产生过程有很大的影响.选取浙江临安市南笤溪以上流域为例,利用L_THIA城市水文模型对流域35年的日雨量记录进行模拟分析,确定城镇化地区降雨径流的关系,探讨了城市化对径流的长期影响,并在此基础上,模拟预测了城市规模扩大对流域径流的影响.研究结果表明,在相同雨量情况下,下垫面条件的变化是导致径流变化的主要因素,随着城市化的发展,径流深度和径流系数将会有显著增加.

<Abstrcat>Along with the rapid development of towns, the intensity of human activities, the variation of buildings, roads and land covers, the increase of land surface impervious, the rainfall-runoff process of a watershed, which is directly related to the underlying surface conditions, is influenced obviously. Long-term Hydrological Impact Analysis, L-THIA, used to simulate the long-term impact of urbanization on runoff is a hydrological model based on GIS technology. In this paper, L-THIA is used in Lin'an watershed in TAIHU River Basin to analyze the effect of the rapid development of towns on runoff with 35 years' precipitation data of the studied watershed, and the relationship between urbanization and rainfall-runoff process is analyzed. Also, the long-term impact of urbanization on runoff is discussed. Meanwhile, the influence of urban extension on rainfall-runoff process is simulated and predicted based on this, and it provides valuable information for the elementary research of the long-term impact of urbanization on the overland runoff. The results show that the changes of underlying surface on watershed have great influences on runoff under the condition of the same rainfall, and in addition, the annual average runoff depth and runoff coefficient will increase with the development of towns. The land use and land cover changes, especially the rapid development of towns, add many difficulties to hydrology simulation, which bring newer and greater challenges to urban hydrological models.