Experimental Study On Impact Of Typical City Underlying Surface On Rainfall Infiltration

City underlying surface is the base of existence and development of the urban, witch isthe summation of urban surface. With the development of urbanization, urban buildingbecome more and more, urban land increases, all these change the form of using urban land.And hydrological character has been influenced remarkable at location. With the urbansurface become harder, obstructing the urban rainfall infiltration seriously, at the same timeconflux time decreases, surface runoff increase, bring a huge pressure on the urban drainagesystem. Moreover, valuable freshwater resource being drained into river through pipesunderground, increasing potamic flood disaster during the rainy season. Thus, not only thesurface water can't be using reasonable but also aggravating the flood disaster, at the sametime the groundwater is dried up for short of supplement of surface water. Most of citiesbecome scarce of water on account of lacking freshwater resource. Obviously, it isfar-reaching meanings to the development of society and economy that find the best spatialstructure of city underlying surface by study the quantitative relationship of the spatialstructure of city underlying surface and rainfall infiltration to increase rainfall infiltration andreduce the storm water runoff, solve the problem of urban water resource shortage in certainlevel. In this paper, the author adopts artificial rainfall test to conduct experimental study onthe quantitative relationship of the spatial structure of city underlying surface and rainfallinfiltration. Change the position and proportion of impervious patch in the uniformexperimental sample field under the same of rainfall and duration of rainfall. Measure thesurface runoff yield and count the rate of rainfall infiltration after simulating rainfall. Theresults show that changing the proportion, shape, evenness and separation of impervious patchcauses different rainfall infiltration yield. Factors of affecting rainfall infiltration of cityunderlying surface spatial structure, proportion of impervious patch have great contribution tothe rate of rainfall infiltration. The effect of shape, evenness and separation of imperviouspatch are less than the contribution of the proportion of impervious patch. However, it is can'tbe neglected that the function of shape, evenness and separation of impervious patch. Ontypical city underlying surface, controlling the rainfall infiltration through adjusting thecombined correlation of shape, evenness and separation of impervious patch better thanchanging the proportion of impervious patch.