Case Study: South Korea's Response to Sea Level Rise and Extreme Coastal Events

11/17/2022

This case study focuses on South Korea (“Korea”) where I am currently based.

The Korean peninsula is surrounded by three stretches of sea coast - the East Sea Coast, the South Sea Coast in the southeast, and the Yellow Sea Coast in the west (The National Atlas of Korea), and is served by 4 major rivers – the Han, the Nakdong, the Geum, and the Yeongsan (Cha et al 2011). More than a quarter of the population, and more than two thirds of industrial buildings, are located in coastal regions (Oh et al 2019).

Sea level rise in the East Sea is the highest amongst the 3 seas, for 2 reasons – increased heat transport in the Kuroshio warm current which transports warm water northeastward from the Philippines (Nagai 2019), and warmer currents in the East Sea caused by global warming (The National Atlas of Korea).

Sea levels along the 3 coasts are projected to rise by between 85cm and 130cm by the year 2100 and, as a result, coastal lowlands will experience a high risk of flooding (RCP8.5) (The National Atlas of Korea).

Residents along the banks of the major rivers are exposed to risk of frequent flooding and droughts (Cha et al 2011). The effects of climate change are projected to cause more frequent and intense extreme weather events, which consequently result in flooding and droughts (Cha et al 2011).

Korea receives 40% more rainfall than the global average, the majority of which occurs from June to September (Cha et al 2011), resulting in regular flood- and drought-related disasters. In the past decade, Korea has experienced almost twice as much heavy rainfall exceeding 100mm per day, and this is expected to increase by more than 2.5 times (Cha et al 2011). The physical condition of the rivers also promotes the occurrence of floods – sections of the rivers are generally interrupted and not straight for long distances, with steep slopes, leading to quick floods with high discharges and high variations in flow (Cha et al 2011).

Flooding can negatively impact water quality when contaminants are transported into water bodies and when sewage and treatment facilities are overloaded (US EPA). Additionally, floods can cause loss of lives, habitats and ecosystem, and property, and necessitate the relocation of those living in the area (Cha et al 2011).

Response to Riverine Flooding

Korea’s riverine flooding response strategy includes the following:-

  • Enhancing the capacity of sewage treatment facilities and constructing facilities to reduce the growth of green algae. Governments at both federal and local levels must protect water supplies by maintaining appropriate salinity concentrations (Cha et al 2011).

  • Enabling water storage by the construction of waterways, weirs, and dams (Cha et al 2011).

  • Managing flood water levels by the dredging of the riverbeds, enlarging tributaries' water gates, and creating flood control areas and underflow areas (Cha et al 2011).

  • Pursuing ecosystem rehabilitation by the restoration of rivers, creation of wetlands, and by moving farmlands from riverine areas (Cha et al 2011).

  • Tasking the Flood Control Offices responsible for each major river with collecting information, analysing flood risks, forecasting, and sending out nationwide flood warnings (MEK).

Response to Coastal Flooding

Korea’s coastal flooding response strategy includes the following:-

  • Enhancing land-use planning, especially in areas such as steep slopes and floodplains (Dolcemascolo et al 2011).

  • Improving the building standards for the construction of essential infrastructure (Dolcemascolo et al 2011).

  • Protecting wetlands (Dolcemascolo et al 2011).

  • Strengthening early warning systems and preparedness capacities; circulating warnings, forecasts, and special weather reports for extreme weather events (Dolcemascolo et al 2011).

  • Designing and maintaining drainage systems under a national framework with standards set by the Ministry of Environment, with local government feedback and enforcement by city government (Dolcemascolo et al 2011).

  • Reviewing sewer system design standards every 5 years. The capital city, Seoul, announced intentions to expand sewer capacity levels (Dolcemascolo et al 2011).

  • Engaging in community-based preparedness – both the national government and the Local Headquarters for Disaster and Safety Management are responsible for evacuation Dolcemascolo et al 2011).

  • Establishing the Global Education and Training Institute for Disaster Risk Reduction (GETI), which engages in advisory, training, advocacy, learning, and technology transfer activities Dolcemascolo et al 2011).

An innovative adaptive solution is being explored in the coastal city of Busan on the southern tip of the peninsula, where a new floating neighbourhood is being developed. It will be constructed on concrete platforms which can rise and fall with water levels while being fixed into the seabed (Fast Company 2022).

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