Street Design Research Based On Low Impact Development

Low-Impact Development (LID) has been derived into different names when it was introduced to China and it is a brand new emerging urban design concept. LID aims to reduce surface runoff (including runoff peak and runoff amount), improve permeable areas, recharge underground water and improve water quality. LID Street has superb hydraulic property and has shown excellent effects on relieving urban storm-water, and purifying runoff quality. It would be a preferred method and trend in street constructions. Nowadays, as an important part of "sponge city" project, LID Street test sections have been put into practice nationwide. Some initial projects are completed gradually. Some research results have been achieved while some problems have emerged as well. It has great academic importance and engineering significance to summarize present research and project achievements and carry out better LID street structure, design method and simulation model.Based on current theoretical and practical achievements, the paper summarizes practical LID infrastructures and analyzes their mechanisms and hydraulic properties. A systematic LID street design and evaluation method is carried out to guide engineering practice.Firstly, based on international and domestic research and practice results, the paper illustrates the definition, meaning and concrete infrastructures such as bio retention, vegetated swale, engineering soil and permeable pipe.Secondly, the paper researches runoff property and the ability of permeable pavement to reduce runoff volume and runoff peak. Different sections are divided in order to determine different functions and hydraulic properties of each sectionThen, a systematic LID street including permeable pavement, bio retention, and vegetated swale is designed. Retention, purification and anti-block functions are taken into consideration in the cross section design.At last, based on hydraulic properties of each LID infrastructure, a reasonable simulation model is established. A prediction model and method is carried out to evaluate LID Street system. Then inorder to guide and evaluate two test sections, the simple calculation software is composed to modelize and standardize the evaluation method.