• 한국환경과학회지
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• 제24권4호
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• pp.471-480
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• 2015

Hydrologic component analysis was conducted to investigate water budget characteristics the Oedocheon watershed, Jeju Island. For this purpose, integrated SWAT-MODFLOW model was applied to this watershed for continuous surface water-groundwater modeling. Pasture and forest-deciduous are the major land use types and these affect general hydrologic component ratio. The spatio-temporal groundwater recharge can be obtained from SWAT and then distributed groundwater recharge can be reproduced by MODFLOW. The groundwater level variation was simulated with distributed groundwater pumping data. The water budget in this watershed was compared with the previous estimated result by Jeju-Do(2013). As this result considered discharge to the coastal side, the discrepancy was found. However, it was found that the overall tendency of both analyses were similar.

• 한국농공학회논문집
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• 제53권6호
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• pp.75-84
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• 2011

The objective of this study is to evaluate the hydrologic impacts of climate and land use changes in a rural small watershed. HadCM3 (Hadley Centre Coupled Model, ver.3) A2 scenario and LARS-WG (Long Ashton Research Station - Weather Generator) were used to generate future climatic data. Future land use data were also generated by the CA-Markov (Cellular Automata-Markov) method. The Soil and Water Assessment Tool (SWAT) model was used to evaluate hydrologic impacts. The SWAT model was calibrated and validated with stream flow measured at the Baran watershed in Korea. The SWAT model simulation results agreed well with observed values during the calibration and validation periods. In this study, hydrologic impacts were analyzed according to three scenarios: future climate change (Scenario I), future land use change (Scenario II), and both future climate and land use changes (Scenario III). For Scenario I, the comparison results between a 30-year baseline period (1997~2004) and a future 30-year period (2011~2040) indicated that the total runoff, surface runoff, lateral subsurface runoff, groundwater discharge, and evapotranspiration increased as precipitation and temperature for the future 30-year period increased. The monthly variation analysis results showed that the monthly runoff for all months except September increased compared to the baseline period. For Scenario II, both the total and surface runoff increased as the built-up area, including the impervious surface, increased, while the groundwater discharge and evapotranspiration decreased. The monthly variation analysis results indicated that the total runoff increased in the summer season, when the precipitation was concentrated. In Scenario III, the results showed a similar trend to that of Scenario II. The monthly runoff for all months except October increased compared to the baseline period.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권7호
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• pp.34-42
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• 2015

Feasibility tests for the hydraulic fracturing were conducted in order to secure additional saline groundwater for irrigating to the land-based aquaculture farm. Two boreholes were placed to the aquaculture farm A and B, respectively. A hydraulic fracturing using single packer was applied to major fracture zones within two boreholes. To identify effects of hydraulic fracturing on securing additional saline groundwater, some selective methods including well logging methods, pumping tests, and groundwater quality analysis were commonly applied to the boreholes before and after the hydraulic fracturing. Enlarging/creating fracture zones, increasing water contents in bedrock near boreholes, and increasing transmissivity were observed after the hydraulic fracturing. Even though the hydraulic fracturing could be an alternative to secure additional saline groundwater to the land-based aquaculture farm, salinity of the groundwater did not meet optimal thresholds for each fingerling in two farms: Fresh submarine groundwater discharge flowed the more into borehole of the farm A that resulted in decreasing a salinity value. Increased saline groundwater quantity in the borehole of the farm B rarely affect to the salinity. Although salinity problem of groundwater limited its direct use for the farms, the mixing with seawater could be effectively used for the fingerlings during the early stage. A horizontal radial collector well placed in the alluvial layer could be an alternative for the farms as well.

• 농업과학연구
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• 제45권3호
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• pp.521-532
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• 2018

In recent decades, the dry stream phenomena of small and medium sized rivers have been attracting much attention as an important social problem. To prevent dry stream phenomena, it is necessary to build an infrastructure that manages rivers. To accurately determine the progress of dry stream phenomena, it is necessary to continuously measure the discharge and other hydrological factors for small and medium sized rivers. However, until now, the flow data for small and medium rivers in Korea has been insufficient. To overcome the lack of supporting data for supporting rational decision-making in policy and project implementation, a short- and long-term hydrological model was developed that takes into consideration hydrological changes such as the increase of the impervious area due to urban development and groundwater pumping, the construction of a large-scale sewage treatment plant, the maintenance of stream-oriented rivers, etc. In the developed model, the distributed grid is represented by three layers: Surface flow, interflow, and groundwater flow. The surface flow and intermediate flow flowed along the flow direction, and the groundwater flow was calculated by a two-dimensional groundwater analysis model such that the outflow occurred in all directions without a specific flow direction. The effects of land use and cover on evapotranspiration and infiltration and the effects of multiple landscapes can be simulated in the developed model.

• 한국지하수토양환경학회지:지하수토양환경
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• 제21권3호
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• pp.64-81
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• 2016

To analyze the influence of various groundwater flow rates (specific discharge) on BHE system with balanced and unbalanced energy loads under assuming same initial temperature (15℃) of ground and groundwater, numerical modeling using FEFLOW was used for this study. When groundwater flow is increased from 1 × 10⁻⁷ to 4 × 10⁻⁷m/s under balanced energy load, the performance of BHE system is improved about 26.7% in summer and 22.7% at winter time in a single BHE case as well as about 12.0~18.6% in summer and 7.6~8.7% in winter time depending on the number of boreholes in the grid, their array type, and bore hole separation in multiple BHE system case. In other words, the performance of BHE system is improved due to lower avT in summer and higher avT in winter time when groundwater flow becomes larger. On the contrary it is decreased owing to higher avT in summer and lower avT in winter time when the numbers of BHEs in an array are increased, Geothermal plume created at down-gradient area by groundwater flow is relatively small in balanced load condition while quite large in unbalanced load condition. Groundwater flow enhances in general the thermal efficiency by transferring heat away from the BHEs. Therefore it is highly required to obtain and to use adequate informations on hydrogeologic characterristics (K, S, hydraulic gradient, seasonal variation of groundwater temperature and water level) along with integrating groundwater flow and also hydrogeothermal properties (thermal conductivity, seasonal variation of ground temperatures etc.) of the relevant area for achieving the optimal design of BHE system.

• 상하수도학회지
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• 제35권6호
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• pp.497-505
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• 2021

This paper investigates the current status of Jeju special self-governing province (JSSGP)'s water infrastructure and recommends directions for improvement. JSSGP relies on groundwater for most of its water resources. Recently, water usage has been steadily increasing due to the increase of residents and tourists while the quality of groundwater has been steadily worsening. Deterioration in water quality of groundwater can be seen through the increase in concentration of nitrate nitrogen and microorganisms. To overcome such problems, water consumption must be reduced by water demand management in all fields including residential and agricultural water use. The quality of water resources should be preserved through the management of pollutants. For efficient management of water resources, great efforts should be made to reduce the leakage rates in household and agricultural water, which is currently at the highest level in the country. Furthermore, diversification of water intake sources other than groundwater is needed, especially for agricultural water supply. For water and sewerage facilities, compliance with drinking water quality standards and discharge water quality standards must be achieved through the optimization of operation management. This process requires recruiting professionals, improving existing workers' expertise, and improving facilities.

• 대한토목학회논문집
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• 제41권1호
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• pp.29-37
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• 2021

물공급 소외지역인 산간 최상류 지역을 위한 현지 적응형 물공급 체계의 도입이 필요하다. 이를 위해서는 수원의 확보와 최적이용 방안 및 연계 가능한 수원과의 결합이 관건이다. 특히 유역 최상류에 위치한 산간지역에는 계곡수와 복류수를 통해 공급되는 지하수 유출량을 활용하는 방안을 강구해야 한다. 본 연구에서는 강원도 춘천의 가뭄발생지역을 대상으로 샌드댐을 활용한 물공급 체계의 개선방안을 모색하였다. 방법은 기존 수원 하부에 모래저류조를 가상으로 설치하여 현재 취수량을 고려한 모델링을 수행하고 추가로 샌드댐에서 취수가능한 양을 산정하는 방식으로 분석을 수행하였다. 샌드댐을 기존 수원의 4배 크기로 적용한 경우 수면경사와 수리전도도의 변화에 따라 배수량이 크게 증대하는 것으로 나타났다.

• 지질공학
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• 제26권2호
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• pp.251-260
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• 2016

댐 저수지의 높은 수위와 댐 외부 지역의 지하수위간의 수두 차이는 지질 방벽을 통한 물의 흐름을 발생시킨다. 이로 인하여 발생한 유역 외 지역의 얕은 지하수위는 토양 습윤화를 초래하여 토지이용에 제약을 가져온다. 본 연구에서는 습윤화가 진행된 소유역내에 지하 1~1.5 m 심도에서 유공관 등의 배수시설을 설치한 후 그 효과를 분석하였다. 배수시설 설치 이전에 비하여 지하수 관측정에서의 수위는 1 m 이상 하강한 것으로 나타났으며, 저수지와 인접한 골짜기 상류(W1 지점)의 경우에는 2m 이상 하강하여 지하수의 빠른 배출에 의한 효과가 발생하였다. 또한, 지역 내 토양수분함량 및 그 표준편차도 감소하여 배수시설에 의한 지하수위 하강이 토양 습윤화를 억제한 것으로 분석되었다. 댐의 설계 시에는 지형지리적 특성을 고려하여 수두 차이에 의한 외부 지역으로의 누수 현상 예측 및 관련 대책을 수립해 나가야 한다.

• 한국환경과학회지
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• 제15권10호
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• pp.967-973
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• 2006

In this study used tank model and specific discharge to calculate low-flow of mountain basin and supply data that need in water resources plan. Low-flow is calculated byspecific discharge and area ratio method as resulted that calculate storage of low-flow by tank model was construed that showd all similar aspect. In judged to help in water resources plan establishment calculating low-flow using model to supplement uncertainty of observed data in that calculate of low-flow ungaged mountain area. It shows by economical and realistic plan until 12 years after development that run parallel and use economic performance analysis result valley flow and groundwater. But wide area water services and Chungju dam since 12 years onward was expose that is economic.

• 환경영향평가
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• 제15권5호
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• pp.299-308
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• 2006

To utilize a closed municipal solid waste landfill site in environmentally secure conditions, it is necessary to verify the stabilization level of landfill leachate. To assess leachate stabilization of an open-dumping municipal solid waste landfill site (Salmi Landfill) which is located at the vicinity of Chungju Reservoir which flows into Paldang Reservoir utilized as Seoul Metropolitan water supplies, the landfill history and surrounding characteristics of the landfill site were surveyed. In this investigation, waste, leachate, groundwater and surfacewater samples from this landfill were physically and chemically analyzed, and the analysis results were evaluated by 'The Criteria of Landfill Waste Stabilization (CLWS)', 'Discharge Criteria of Landfill Leachate', 'The Criteria of Domestic Use in Groundwater Quality', and 'The Criteria of Domestic Use in Surfacewater Quality' that promulgated by Korean Ministry of Environment. From the analysis results on the Salmi open-dumping landfill, C/N ratio was 18.9 and $BOD/COD_{Cr}$ ratios in leachate were higher than 1/10. Based on the CLWS, this results seemed to imply that the process of leachate stabilization at this landfill was still proceeding.