Research On The Construction And Potential Evaluation Of Rainwater Utilization Mode

For a long time,the comprehensive utilization of rainwater resources in China’s urban planning has been lacking enough attention.With the improvement of civil living standards,the public has higher requirements for drinking water and landscape water,which provides a broad prospect for the promotion and application of rainwater utilization technology.Therefore,the establishment of a scientific and reasonable rainwater utilization model and the evaluation of rainwater utilization potential in each region have become equally important as the demand of urban development.This paper studied the construction method of appropriate rainwater utilization mode and the evaluation of rainwater utilization potential,and the rainwater utilization model construction and the rainwater utilization potential evaluation were carried out by taking the central urban areas of Beijing,Tianjin and Hebei as examples.The main research contents and results were as follows:（1）The method of rainwater utilization region division was proposed,and the Beijing-Tianjin-Hebei region was taken as an example to divide the rainwater utilization region.The center of every city was selected as the target area of rainwater utilization mode construction,which was divided into living activity area,production security area and ecological conservation area.The efficiency demands for the regional rainwater utilization and control were analyzed,which is concluded that:living activity areas should attach great importance to the social benefit and ecological benefit,production security areas should attach great importance to the economic benefits,and ecological conservation areas should attach great importance to the economic benefits and economic benefits.（2）A planning and solving model for the appropriate mode of rainwater utilization was established.Through the analysis of the economic,natural and social conditions of planning area,and the performance characteristics of the rainwater utilization technologies,restrictions on appropriate technology types of rainwater utilization,the limitation on rainwater utilization cost investment,the limitation on coverage area of rainwater utilization technologies,the limitation on the planning density of rainwater utilization technologies restrictions and the limitation on feature matching of rainwater utilization technologies were set as constraint conditions.The comprehensive benefit of each rainwater utilization area was set as objective function.Hench,a planning and solving model of rainwater utilization appropriate was established on EXCEL platform.（3）With the help of the rainwater utilization mode solution model,the appropriate rainwater utilization mode was established for the central urban areas of Beijing,Tianjin and Hebei.Under this mode,41%area of the total 5159 km²area in Beijing,Tianjin and Hebei was covered by rainwater utilization technologies,and the runoff control area of the central urban area reached 100%except for Qinhuangdao which was 94.5%.In addition,a statistic analysis on the cost efficiency of rainwater utilization in every central city region of Beijing-Tianjin-Hebei was conducted.In conclusion,average annual investment cost on rainwater utilization of center urban unit area was 3.1 yuan/m²,the average annual economic benefit,ecological benefit,social benefit and the total benefit were 2.9 yuan/m²,34.6 yuan/m²,1.1 yuan/m²and 32.8yuan/m²respectively,and the average benefit cost ratio was 10.7.（4）The method of rainwater utilization potential assessment was developed,and the rainwater utilization potential assessment of the central urban area of Beijing,Tianjin and Hebei was carried out under the appropriate mode of rainwater utilization.In the central urban area of Beijing-Tianjin-Hebei,annual total rainfall was 2.78×10¹⁰m³,and annual available rainfall water was 2.23×10¹⁰m³,which accounted for 80.1%of the total rainfall water.Saving irrigation amount,infiltration and recharge amount,and the collection and storage amount accounted for 30.7%,39.5%and 9.9%respectively.The total available potential of rainwater increased by 52.5%compared with the original state.