Method Study On Optimization Of High Density Urban Land Layout Of Based On Low Impact Development

With the rapid advancement of urbanization in China,the frequent occurrence of rain and flood disasters has become a serious problem that restricts the healthy development of cities.Especially in the areas of high urbanization(urbanization rate greater than 70%)represented by megacities and large cities,due to the rapid expansion of cities and the disorderly development of land use,the proportion of urban impervious areas is too high,leading to the concentration of transient rain and flood.The impact is difficult to effectively dissipate through the rigid underlying surface of the city,so extreme weather events can easily lead to catastrophic consequences.In this context,the state has made major decisions to build a sponge city,so that the city can have a good elasticity like a sponge in adapting to environmental changes and coping with natural disasters.Among them,the lowimpact development concept and its measures play an important role in the construction of the sponge city because of its good urban stormwater control ability.However,the new urban stormwater management concept based on low-impact development measures still pays more attention to the site scale and the specific measures effect,and the research on the low-impact development effect after the land use sponge modification and the land layout optimization under the basin scale less.In view of this,this paper will carry out relevant research based on this point,and try to provide decision-making basis for land use planning in high-density urban areas from the perspective of urban rainwater safety.This study takes the Dasha River Basin in Shenzhen as the research area.The research objective is to explore an optimization method for high-density urban land use layout under the concept of low impact development.The research idea is to couple the GIS with the SWMM model(Stormwater Management Model)to realize the rapid construction and hydrological effect analysis of the urban stormwater management model at the basin scale.Specifically,the GIS data platform is used to statistically analyze the land use composition in the study area,and the four types of land for industrial area use,residential land,science and education land,and park green space are identified as the main research objects.Secondly,using the lowimpact development module in the SWMM model,the urban stormwater regulation characteristics and effect sizes of four types of land use are analyzed under different rainfall periods.Based on this analysis,combined with the practical needs of urban renewal and transformation in Shenzhen,four land use planning scenarios with obvious contrast characteristics were constructed to explore the multi-scenario land layout plan for the high-density built-up area under the sponge city construction goal.Potential impact characteristics of stormwater regulation.After analyzing the urban stormwater management model,it can be obtained that the current development scenario has the weakest rainwater control ability.Compared with this,the ability to regulate traditional urban land use planning scenarios remains basically unchanged.The rainwater control capability of urban land use planning scenarios under lowimpact development has improved.Finally,the optimization of urban land use layout under low-impact development is the best at the level of rain and flood control.Therefore,it is suggested that in the current flood disasters,the best way to lowimpact development and layout optimization will be to alleviate the problem of rain and flood disasters in high-density urban areas,and then provide new land use planning ideas for the construction of sponge cities in Shenzhen.Decision basis.