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Research Reports

Research on institutional improvements regarding the utilization and management of groundwater discharge in urban areas
  • Author Kyoung-Ho, Kim
  • Researchers
  • Date 2020-10-31
Ⅰ. Background and Objective of the Study
o Large-scale discharge of groundwater from projects designed to develop underground spaces in urban areas needs to be actively utilized and managed to conserve groundwater and ensure the integrity of water circulation systems. Under the Groundwater Act, etc., there are regulations that require the establishment of reduction measures and utilization plans for discharged groundwater generated from subways and buildings. However, the effectiveness of current systems in place is insufficient in terms of both effective management and utilization.
ㅇ The main purpose of this study is to find ways to improve the management system, including the legal framework, to effectively manage and utilize discharged groundwater in urban areas. This study also identifies the current status and issues pertaining to systems utilizing and managing discharged groundwater, and establishes the direction of relevant policies for effective groundwater discharge management. Based on its findings, this study ultimately proposes various measures and plans to improve legal systems governing the management and utilization of groundwater discharge in urban areas.

Ⅱ. Characteristics of Groundwater Discharge in Urban Areas
o Previously published information on discharged groundwater and its usage suggests that more groundwater is being discharged in urban areas to the extent that the volume of discharged groundwater exceeds the capacity of groundwater developed and utilized. Since groundwater discharge is mostly used for the maintenance of rivers, it greatly contributes to the loss of groundwater reserves.
ㅇ In particular, in the case of buildings, the legal system for utilizing and managing groundwater discharge is ineffective because of regulations that report any instances of groundwater discharge above the standard volume (30 tons/day). Furthermore, the use of groundwater discharge to secure the integrity of water circulation, such as wastewater, is deemed insufficient.

o This study examines the quantitative relationship between the generation of groundwater discharge and fluctuation of groundwater levels (depletion) based on the amount of discharged groundwater as well as data from the groundwater Auxiliary Observation Network available in urban areas. Based on this, this study proposes a plan for establishing groundwater level management zones and a monitoring plan for discharged groundwater.
ㅇ In terms of case studies, this study uses machine learning to evaluate the effect of spatial variables, such as groundwater discharge volume, land use, and hydrogeological characteristics, on the drop in groundwater levels in Seoul. It also spatiotemporally examines significant water level drops caused by groundwater discharge in urban areas near subways. Moreover, the results of this study were used in proposing a plan to establish high-risk zones and control threshold for groundwater levels in urban areas.

ㅇ Observations through the Seoul Auxiliary Observation Network proved that the continuous drop in the groundwater level was not subject to rainfall. Here, the separation distance of subway lines, volume of discharge from subways, and depth of soil were identified as major influence factors. Furthermore, significant drops in groundwater levels outside the confidence interval of forecasted groundwater levels set by time-series analyses were identified via the observation network adjacent to buildings under construction. This presented means to utilize the Auxiliary Observation Network as a major means of measuring groundwater discharge.

Ⅲ. Means to Utilize/Manage Groundwater Discharge
o This chapter examines the current status and pending issues pertaining to the utilization and management of groundwater discharge in Korea. It also offers plans to promote the use of groundwater discharged during construction, and the management of groundwater discharge when such means of using discharged groundwater are implemented. Here, the current status of managing, reducing, measuring, and utilizing groundwater discharge at different municipalities was reviewed, and relevant problems and improvements were presented as well.
ㅇ Reviewing the Ministry of Environment’s guidelines for performing groundwater work, and confirming the management status of local governments (public official interviews, etc.) revealed that the utilization and management of groundwater discharge in the private sector were poor due to the lack of management and administrative systems for discharged groundwater. Also, despite the guidelines for managing construction (measurement, order and drainage techniques, and application of construction methods), this study explored the necessity of supplementing a more specific method of measuring and monitoring groundwater discharge in accordance with relevant legal systems and forecasting methods linked to underground safety impact assessments.
ㅇ Furthermore, based on the basic principles of utilizing groundwater discharge, this study reviewed and proposed plans for utilizing water at buildings in urban areas (geothermal heating and cooling in facilities, river maintenance water, etc.) as well as artificial recharge methods. It also explored evaluation processes and economic review plans for revitalizing the use of groundwater discharge.

IV. Plans for Improving Groundwater Discharge Management Systems
o To achieve the goal of this study, issues pertaining to groundwater discharge management systems under the current Groundwater Act were derived in this study. This study also proposed the direction of improvement and specific improvement plans for current management systems. In particular, to reinforce public management of groundwater, policy improvements rationalizing the mandatory reporting of groundwater discharge instances were established, and a detailed legal and regulatory improvement plan was proposed in this study as well.
ㅇ Based on potential improvements identified in the legal systems related to discharged groundwater, this study found that it was necessary to strengthen the legal system in terms of groundwater conservation and process management. To this end, this study established the direction of management policies regarding the rationalization of groundwater discharge reporting regulations, a system for obligating the use of discharged groundwater, a pre-evaluation system for discharged groundwater, management zones (such as groundwater preservation zones), and implemented a fee-based usage system for groundwater discharge.
ㅇ In the context of the above policy direction, this study developed an improvement plan centering on the Groundwater Act. Particularly, given the fact that the scale and volume threshold for reporting groundwater discharge did not reflect reality, this study proposed a revision of the legal system for groundwater discharge reporting thresholds and procedures. Improvements to the legal system proposed in this study include the revision of groundwater discharge reporting regulations, revision of groundwater discharge usage regulations, revision of the water quality management system for groundwater discharge, revision of the groundwater conservation zone system, arrangement of groundwater usage fees, and preparation of pre-evaluation measures such as groundwater impact assessments.
ㅇ In particular, since the regulations on the use of discharged groundwater are stipulated as items applicable only to the wastewater quality standards, this research deemed it urgent to amend relevant provisions and expand the use of groundwater discharge, including the artificial recharge of groundwater. Furthermore, this study deemed it necessary to include the proper definition of groundwater discharge in regulations governing groundwater quality management, and to prepare a basis for applying the groundwater quality standards for different applications.

o (Recommendation) This study proposes amendments to the Groundwater Act, etc. in order to solve the limitations of the existing groundwater discharge management systems. However, to apply such amendments, this report recognized the need for comprehensive revisions to current groundwater management policies. Moving forward, in order to improve the practices managing groundwater, including discharged groundwater, there is an urgent need to raise awareness of the value and publicness of groundwater preservation. But above all, for the systematic management of groundwater developments and utilization facilities, the government’s regulatory and administrative support, reinforcement of groundwater resource conservation policies are required. To achieve the goal of restoring proper water circulation, which is the basic principle of integrated water management, the central government and local municipalities are expected to exert efforts to improve relevant systems and to actively utilize the results of this study.