서울시 재정비촉진지구 공원녹지 계획 유형과 이에 따른 홍수 피해 저감 효과 분석

서울 재정비촉진지구의 공원녹지 계획과 홍수 피해 저감 효과를 분석했다.

The impervious surface area in Seoul accounts for 54.6% of its total land area, and the increasing flood damage in the city each year highlights its insufficient capacity to manage disasters under climate change conditions. In response, Seoul has initiated the "Green Ecological Urban Center Re-creation Strategy" (Mayor's Directive No. 116) to establish green infrastructure capable of mitigating flood impacts during heavy rains. These plans for green infrastructure are most effective when formulated at a metropolitan scale. Redevelopment promotion zones are designated to improve residential environments, expand infrastructure, and restore urban functionality in deteriorated areas.

Unlike other urban regeneration projects, these zones are implemented comprehensively and on a large scale, playing a significant role in increasing urban green space. However, current urban planning often includes declarative rather than concrete disaster management plans reflecting climate change and disaster vulnerability. In environmental assessments for redevelopment promotion plans, green planning as green infrastructure lacks consideration for its location and morphological elements.

Therefore, to enhance urban disaster management functions, it is necessary to empirically study whether the green planning in redevelopment promotion zones incorporates disaster vulnerability considerations. Existing studies on green infrastructure have primarily focused on enhancing resilience, classifying green infrastructure types, and analyzing their relationship with flood damage costs. Previous research on green spaces within redevelopment promotion zones has been limited to issues such as accessibility and service levels. This study aims to analyze the effectiveness of park and green space planning in redevelopment promotion projects as an urban disaster management element.

To identify target areas for analysis, redevelopment promotion zones in Seoul with records of flooding were initially selected, focusing on locations requiring disaster management review. Subsequently, detailed investigations of the site plans were conducted, classifying park and green space plans into linear, dispersed, and concentrated types. Three zones—Sillim, Noryangjin, and Hannam Redevelopment Promotion Zones—were chosen as case studies due to their history of changes in park and green space planning. The analysis examined whether guidelines and standards for park and green space planning were established for the selected zones.

Using site conditions, plans before and after modifications, and urban planning facility maps, 3D modeling of terrain and buildings was conducted with Rhino7. Rainwater runoff simulations, using the Kangaroo plugin in Grasshopper, were performed to trace water flow paths, and the frequency and number of building collisions were analyzed. Key findings are as follows: The Sillim Redevelopment Promotion Zone transitioned from a dispersed to a linear park and green space type, reducing the green space area by 580 m². The Noryangjin Redevelopment Promotion Zone changed from a linear to a concentrated type, reducing green space by 7,975 m².

The Hannam Redevelopment Promotion Zone transitioned from a linear to a dispersed type, with a reduction of 29,191 m². In the Sillim and Noryangjin zones, park and green space plans were modified based on environmental management plans and rapid integrated planning guidelines. The Hannam zone’s green space planning was influenced by changes in the maximum building heights and architectural plans to accommodate the area's hilly terrain. In the Sillim and Noryangjin zones, post-modification plans showed reduced rainwater collision frequency and fewer impacted buildings compared to the original plans.

Conversely, in the Hannam zone, the original plan demonstrated lower collision frequencies than the modified plan. This study holds significance as it quantitatively and qualitatively analyzes the impact of park and green space planning on urban disaster management in redevelopment promotion projects. Given the comprehensive and metropolitan nature of these projects, their park and green space planning should consider not only the expansion of green areas and leisure spaces but also urban disaster management and climate change factors. Customized plans tailored to each area’s terrain and building layout are essential.

However, the study has limitations, such as focusing on rainwater flow and collisions without considering drainage capacity or soil characteristics. Although the simulations were verified by comparing results for Gangnam Station with urban flood risk maps, predicting exact flood occurrences remains challenging. Additionally, due to a lack of examples in the comprehensive survey, not all combinations of dispersed, linear, and concentrated park and green space types could be analyzed. 서울의 불투수면적의 비율은 전체 토지 면적의 54.6%으로, 매해 증가하는 서울시의 홍수 피해는 기후변화 상황에서 재난재해로 인한 피해를 조절하는 능력이 부족하다는 점을 반증하고 있다. 이에 대한 대응으로 서울시는 “녹지생태도심 재창조 전략”(시장방침 제 116호) 을 시행해 폭우 시 홍수 조절효과를 낼 수 있는 그린인프라를 조성하려는 계획을 진행 중에 있다.

이러한 그린인프라에 대한 계획은 광역적인 계획이 가능할 때 가장 효과적이다. 재정비촉진지구는 도시의 낙후된 지역에 대한 주거환경의 개선, 기반시설의 확충 및 도시기능의 회복을 광역적으로 계획하고 체계적ㆍ효율적으로 추진하기 위하여 지정하는 지구이다. 이와 같이 다른 도시정비사업과는 달리 종합적이며 대규모로 시행이 된다는 특징을 가지기 때문에 도심 내 녹지 면적 확충에 중요한 역할을 하는 사업이 된다. 이와 관련하여 현행 도시계획의 내용에는 기후변화와 재해취약성을 반영한 방재계획이 포함되어야 하나, 실제로는 구체성 없는 선언적 내용만 반영되고 있는 실정이다. 실제로 정비촉진계획의 환경성평가에서 녹지계획 부분은 그린인프라로서 위치와 형태적 요소는 고려되지 않고 있다. 따라서 도시 방재기능의 강화를 위한 도심 녹지공간의 효과적인 운영을 위해서는, 광역적이고 종합적인 계획이 가능한 재정비촉진지구의 녹지 계획이 재해취약성을 반영한 배치가 적용되었는지에 대한 실증적인 연구가 필요하다. 기존의 그린인프라에 관련한 연구는 주로 회복력 강화, 그린인프라의유형 분류, 홍수피해액(경제적 홍수 피해)과의 관계 규명 등에 초점을 맞추고 있으며, 재정비촉진지구 내의 녹지에 관련한 선행연구는 접근성, 서비스 수준에 관련한 정도로 진행되었다.

재정비촉진사업의 공원녹지 계획에 대하여 도시 방재 요소로서의 실효성을 분석하기 위하여, 지형과 건축물에 따른 우수의 흐름을 시뮬레이션한다. 분석의 대상을 선정하기 위하여 서울시의 재정비촉진지구 중 침수흔적이 있는 지구를 1차적으로 선별하여 방재 요소의 검토가 필요한 곳을 분석하였다. 이 후 앞서 선별한 사업 대상지의 도면을 전수조사하여 공원녹지 계획의 유형을 선형, 분산형, 집중형으로 분류하였다. 공원녹지를 계획함에 있어서 홍수 피해에 대한 고려가 진행되었는지 확인하기 위하여 공원녹지 계획에 변경이력이