수변지역 도시재생에 있어 저영향개발기법(LID)의 적용방안 및 효과

Abstract

Recent abnormal rainfalls owing to climatic change have caused rapid changes in the water environment yielding floods, heavy snowfalls, and droughts in urban areas. Such natural disasters not only threaten the quality of urban life, but also wreak havoc on human lives in some extreme cases. This study was conducted to identify and formulate effective ways to minimize the impacts of such a rapidly changing water environment especially in waterfront areas, one of the most vulnerable loci, by applying the LID (Low Impact Development) technique in urban regeneration plans for the areas. To discover a more practical plan and to present a viable policy, several case-study areas were selected on which to apply the technique and the effect was estimated by using the LIDMOD2 model. First, case studies from the U.S. and European countries with active employment of the LID technique were gathered to find out which specific aspects of the LID technique can planning elements with potential for application in urban regeneration plans for waterfront areas were culled via analyses of flood reduction plans by the US Environmental Protection Agency and individual states as well as previous studies on the LID technique used in Korea and other countries. Based on the results, an appropriate method with which to apply the LID technique in the processes as well as the frameworks of general urban regeneration plans was presented. By applying the obtained processes and planning elements to two types of study areas in order to prepare plans and designs of environmentally friendly urban regeneration and subsequently to suggest their effects, it was possible to review the feasibility of such application. Plans were applied through four stages in total: selection of areas based on development density and pressure analysis of locations and current status setting up of goals, and application of the LID technique. After applying the plans, effects on nonpoint pollution source load according to change of land usage and improvement in peak flow or surface runoff were estimated by using LIDMOD2. For the process, this study selected two areas for case studies: Cheongsong-eup in Cheongsong-gun and Yangpyeong-eup in Yangpyeong-gun. Appropriate plans and designs were drawn with application of the LID technique. The focus on the region with low development density and low development pressure in the future, namely Cheongsong-gun, was laid on guarantee of minimal living environment, while that on a region with high development density and high development pressure in the future, namely, Yangpyeong-gun was laid on advanced approach to induce environmentally-friendly urban development. The application of the LID technique to Cheongsong-gun yielded major changes compared to the existing drainage system including the following modification of drainage system customized according to slopes establishment of redevelopment areas and riverside water retention areas and open spaces using public facilities and connection with the drainage system. In Yangpyeong-gun, the plan was based on establishing a link with existing redevelopment projects, installation of a distributive water circulation system, functional connection between streams and a national river, and linking of river buffer zones. In conclusion, total impervious areas in Cheongsong-gun were reduced from 75.07% to 73.41% annual surface runoff was improved by 7.4% and annual infiltration rate by 6.7%. In terms of pollution loads, T-N concentration was improved by 11.5% T-P concentration 9.3% and BOD 9.4%. Peak flow was also improved by 8.3%. Total impervious areas in Yangpyeong-gun were reduced from 75.9% to 71.07% annual surface runoff was improved by 17.4% and annual infiltration rate by 20.2%. In terms of pollution loads, T-N concentration was improved by 17.1% T-P concentration 16.1% and BOD 16.2%. Peak flow was also improved by 13.1%. Based on the case studies, results of an improvement plan can be enhanced through the systematic application of the LID technique on urban regeneration projects in waterfront areas. In so far as environmentally- friendly development, the LID technique could be applied the pilot project of water circulationtype waterfront town in connection with the Four Major Rivers Restoration Project. To this end, this paper propose the following as in-depth analysis of target areas configuration of the water circulation system based on development pressure and density establishment of strategy utilization of estates of public institutions coordination with current local development plans, and organic interoperation with existing drainage and sewer system. Furthermore, it propose the application of the LID technique to the prior environmental review system, especially to items on geomorphology damage and soil contamination as well as amenity in its operation handbook. In connection with the total water pollution load management system, the technique might be applied by using the concept of Biotope Area Factor. However, it would be necessary to conduct complementation and verification through monitoring in the future so as to refine the proposal. In connection with resident support, the study propose the methods by which to apply the LID technique to develop as substantial elements in projects, ultimately to increase income and promote welfare.