도시 지하공간 조성에 따른 환경영향 관리 방향 연구 = Urban Underground Planning and Environmental Impact Management

다국어 초록 (Multilingual Abstract)

The term underground space refers both to the natural microscopic pores in the geomaterials and to the manmade excavations. Both naturally and artificially created underground spaces offer valuable services as storage space of geothermal energy, groundwater, mineral resources, fuel storage tanks, utility lines, transportation routes, co2 gas, nuclear wastes and many more subterranean structures. The value of underground spaces, especially urban underground spaces is steadily increasing due to the limited surface capacity to hold soaring demands of urban infrastructure, furthered with the heightened interests on the greener, more sustainable cities. This study pursues to examine the values of the urban underground spaces and make policy suggestions for more environmentally friendly use and management of them. The legal definition of underground ownership is still ambiguous across the world, while use of underground space is expanding further into the depths as the shallow underground space is getting overpopulated with the utilities lines and other commercial uses, and also thanks to the rapid improvements and innovations in the underground construction technologies. Consequently, the need for ownership definition and regulated uses of the deep underground spaces arises. Both the City of Seoul and the Gyeonggi Province have announced their interests in expanding transport infrastructures located underground at depths greater than 40~50m, namely the deep underground as well as the plans to regulate its private use. The underground construction and operation of underground space may instigate environmental impacts such as noise, vibration, runoff, dust, air pollution, and ground subsidence. During the operation of underground structures, especially the ones designed for human activities, associated concerns may expand into the indoor air quality, lighting and public safety as well. Underground construction inevitably makes impacts on natural resources sometimes causing irreversible loss of space, geotechnical characteristics, geothermal energy, and cultural values. The values of the natural underground resources, especially the climate-regulating values of topsoil and groundwater are getting more attention. Thus, a new approach for more sustainable underground construction practice that reflects the value of the underground is warranted. With the advances in the 3D urban planning techniques, underground planning can now be done more systematically. However, due to technical difficulty and high costs associated with gaining information of the underground space, the rigorous urban planning applications on the underground space design is still limited. Also the nation`s current regulatory mechanisms of environmental impacts related with construction work including the Environmental Impact Assessment system, Construction Codes for Low Environmental Impacts, and the 3rd National Low Environmental Impact Construction Management Plan have few direct implications on the underground space use planning as they focus mostly on the management of the direct impacts (e.g., construction runoffs, waste management, noise, vibration, dust, topographical changes) of the construction. As conclusions, three policy directions for environmentally friendly urban underground space planning and use were made: (1) establishing a long-term vision for sustainable underground use incorporating the concept of low-impact development (LID), (2) developing a master plan for urban underground use that includes the classification scheme of underground space based on the characteristics such as the potential use, depth, and ownership, and a targeted planning framework for the efficient use of each class of underground spaces (3) regulatory reform for more consistent and concerted management of underground construction.