• 제목/요약/키워드: management of coastal groundwater

검색결과 36건 처리시간 0.028초

Quantitative Assessment of Coastal Groundwater Vulnerability to Seawater Intrusion using Density-dependent Groundwater Flow Model (분산형 해수침투 모델을 이용한 양적 지표 기반의 해안지하수 취약성 평가연구)

  • Chang, Sun Woo
    • Journal of Soil and Groundwater Environment
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    • 제26권6호
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    • pp.95-105
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    • 2021
  • Extensive groundwater abstraction has been recognized as one of the major challenges in management of coastal groundwater. The purpose of this study was to assess potential changes of groundwater distribution of northeastern Jeju Island over 10-year duration, where brackish water have been actively developed. To quantitatively estimate the coastal groundwater resources, numerical simulations using three-dimensional finite-difference density-dependent flow models were performed to describe spatial distribution of the groundwater in the aquifer under various pumping and recharge scenarios. The simulation results showed different spatial distribution of freshwater, brackish, and saline groundwater at varying seawater concentration from 10 to 90%. Volumetric analysis was also performed using three-dimensional concentration distribution of groundwater to calculate the volume of fresh, brackish, and saline groundwater below sea level. Based on the volumetric analysis, a quantitative analysis of future seawater intrusion vulnerability was performed using the volume-based vulnerability index adopted from the existing analytical approaches. The result showed that decrease in recharge can exacerbate vulnerability of coastal groundwater resources by inducing broader saline area as well as increasing brackish water volume of unconfined aquifers.

Analysis of domestic and overseas coastal groundwater management laws and policies (국내외 해안 지하수관리 법·정책 사례 분석)

  • Shim, Young-Gyoo;Chung, Il-Moon;Chang, Sun Woo
    • Journal of Korea Water Resources Association
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    • 제57권9호
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    • pp.633-643
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    • 2024
  • Many coastal countries have developed and used a wide range of technologies and policy measures to protect freshwater aquifers and groundwater resources from seawater intrusion, and have established and implemented a foundation to legally and institutionally support them. This study covers coastal states in the eastern United States, the Netheland, India and Japan. The goal of this study is to analyze each country's legal and policy measures for coastal groundwater management. By introducing Jeju Island's groundwater standard level system, we aim to provide a basis for future discussions on groundwater management measures not only in Jeju Island but also in coastal areas of Korea. As a result of the analysis, despite the various contents and aspects of coastal groundwater management based on local issues and characteristics around the world, in order to achieve the common goal of securing a stable amount of groundwater withdrawal and preventing seawater intrusion and to maximize the efficiency of groundwater management, it is understood that attempts are being made to establish optimal management measures, laws, systems, and policies based on several key factors. First, considering the hydrogeological characteristics and status of coastal groundwater, a separate special management system is being established and implemented within the scope of the national groundwater management system. In addition, preventing and maintaining groundwater level decline through limiting the amount of groundwater withdrawal and preventing seawater intrusion are key policy goals and policy tools, and it is suppored by research and development. Finally, tt was found that synergy effects are being sought by using various other policy tools and measures in a complex manner.

Characterizing Groundwater Discharge and Radon Concentration in Coastal Waters, Busan City (부산 해안지역의 물의 라돈 농도와 지하수 유출 특성)

  • Ok, Soon-Il;Hamm, Se-Yeong;Lee, Yong-Woo;Cha, Eun-Jee;Kim, Sang-Hyun;Kim, In-Soo;Khim, Boo-Keun
    • Journal of Soil and Groundwater Environment
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    • 제16권5호
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    • pp.53-66
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    • 2011
  • Groundwater which infiltrated in recharge areas discharges in the forms of evapotranspiration, baseflow to streams, groundwater abstraction and eventually flows into the sea. This study characterized radon-222 concentration and electrical conductivity (EC) in coastal groundwater discharge, well groundwater, Ilkwang Stream water, and seawater in the coastal area of Busan Metropolitan City and subsequently estimated groundwater discharge rate to the sea. The median value of Rn-222 concentration is highest in well groundwater (18.36 Bq/L), and then decreases in the order of coastal groundwater discharge (15.92 Bq/L), Ilkwang Stream water (1.408 Bq/L), and seawater (0.030 Bq/L). The relationship between Rn-222 concentration and EC values is relatively strong in well groundwater and then in seawater. However, the relationship is not visible between coastal groundwater discharge and Ilkwang Stream water. The groundwater discharge rate to the sea is estimated as $3,130m^3$/day by using radon mass budget model and $16,788m^3$/day by using Darcy's law.

Analysis of Hydraulic Gradient at Coastal Aquifers in Eastern Part of Jeju Island (제주도 동부지역 해안대수층의 조석에 의한 수리경사 변화 연구)

  • Kim, Kue-Young;Shim, Byoung-Ohan;Park, Ki-Hwa;Kim, Tae-Hee;Seong, Hyeon-Jeong;Park, Yun-Seok;Koh, Gi-Won;Woo, Nam-Chil
    • Economic and Environmental Geology
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    • 제38권1호
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    • pp.79-89
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    • 2005
  • Groundwater level changes in coastal aquifers occur due to oceanic tides, where the properties of oceanic tides can be applied to estimate hyadraulic parameters. Hydraulic parameters of coastal aquifers located in eastern part of Jeju island were estimated using the tidal response technique. Groundwater level data from a saltwater intrusion monitoring well system was used which showed tidal effects from 3 to 5 km. The hydraulic gradient was assessed by utilizing the filtering method from 71 consecutive hourly water-level observations. Calculated hydraulic diffusivity ranged from 2.94${\times}10^7m^2d^{-1}$ to 4.36${\times}10^7m^2d^{-1}$ . The hydraulic gradient of the coastal aquifer area was found to be ~$10^{-4}$, whereas the gradient of the area between wells Handong-1 and 2 was found to be ~$10^{-6}$, which is very low comparatively. Analysis of groundwater monitoring data showed that groundwater levels are periodically higher near coastal areas compared to that of inner land areas due to oceanic tide influences. When assessing groundwater flow direction in coastal aquifers it is important to consider tidal fluctuation.

Evaluation of Percolation Rate of Bedrock Aquifer in Coastal Area (해안지역 암반대수층의 침누수량 평가)

  • Lee, Jeong-Hwan;Jung, Haeryong;Park, Joo-Wan;Yoon, Jeong Hyoun;Cheong, Jae-Yeol;Park, Sun Ju;Jun, Seong-Chun
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • 제14권1호
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    • pp.21-33
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    • 2016
  • Estimation of groundwater hydrologic cycle pattern is one of the most critical issues in sustainable management of groundwater resources in coastal area. This study estimated groundwater percolation by using the water balance methodology and hydrogeological characteristics of land use and soil. Evapotranspiration was computed by using the Thornthwaite method, and surface runoff was determined by using the SCS-CN technique. Groundwater storage change was obtained as 229 mm/a (17.8% of the average annual rainfall, 1286 mm/a), with 693 mm/a (60.1%) of evapotranspiration and 124 mm/a (9.6%) of surface runoff. Rainfall and groundwater storage change was highly correlated, comparing with the relationships between rainfall and evapotranspiration, and between rainfall and surface runoff. This result indicates that groundwater storage change responds more sensitively to precipitation than evapotranspiration and surface runoff.

Validation of Fresh-Saltwater Sharp-Interface Model Using Freshwater Lens Hydraulic Experiment (담수렌즈 수리모형을 이용한 담수-염수 경계면 수치모델의 검정)

  • Hong, Sung Hun;Park, Namsik
    • KSCE Journal of Civil and Environmental Engineering Research
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    • 제26권3B호
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    • pp.263-269
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    • 2006
  • An optimization model was developed for groundwater development and management in coastal areas. The optimization model consists of coastal groundwater flow model and optimization techniques. The objective of this work is to validate sharp-interface model which is one of major components of the optimization model. A laboratory experimental model is built to simulate freshwater lens, i.e., layer of freshwater floating on top of saltwater, phenomena. Experimental results for the position of fresh-saltwater sharp-interface and the salinity in well are compared with numerical results. Average ratio of relative error is estimated approximately between 2.91% and 4.39%. And the numerical results are in good agreement with the laboratory results of water quality in well in addition to the position of sharp-interface. Accordingly the evaluation of coastal groundwater flow using sharp-interface model can produce reasonable results.

Rural Groundwater Monitoring Network in Korea (농어촌지하수 관측망)

  • Lee, Byung Sun;Kim, Young In;Choi, Kwang-Jun;Song, Sung-Ho;Kim, Jin Ho;Woo, Dong Kwang;Seol, Min Ku;Park, Ki Yeon
    • Journal of Soil and Groundwater Environment
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    • 제19권4호
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    • pp.1-11
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    • 2014
  • Rural groundwater monitoring network has been managed by Korea Rural Community Corporation (KRC) since 1998. The network consists of two kinds of subnetworks; rural groundwater management network (RGMN) and seawater intrusion monitoring network (SIMN). RGMN has been operated to promote a sound and sustainable development of rural groundwater within the concerned area for groundwater quality and quantity. SIMN has been operated to protect the crops against hazards by the saline water in coastal areas in which the shortage of irrigation water become a main problem for agriculture. Currently, a total of 283 monitoring wells has been installed; 147 wells in 79 municipalities for RGMN and 136 wells in 52 ones for SIMN, respectively. Two subnetworks commonly monitor three hydrophysical properties (groundwater level, temperature, and electric conductivity) every hour. Monitored data are automatically transferred to the management center located in KRC. Data are opened to the public throughout website named to be the Rural Groundwater Net (www.groundwater.or.kr). Annual reports involving well logging and hydrochemical data of RGMN and SIMN have been published and distributed to the rural water management office of each municipalities. In addition, anyone who concerns about RGMN an SIMN can freely download these reports throughout the Rural Groundwater Net as well.

Numerical Modeling of Seawater Intrusion in Coastal Aquifer (연안 대수층에서 해수침투 축성 해석)

  • 이연규;이희석
    • Tunnel and Underground Space
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    • 제14권3호
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    • pp.229-240
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    • 2004
  • Coastal aquifers may serve as major sources fur freshwater. In many coastal aquifers, intrusion of seawater has become one of the major constraints imposed on groundwater utilization. The management of groundwater in coastal acquifers means making decision as to the pumping rate and the spatial distribution of wells. Several numerical techniques for flow and solute transport simulation can provide the means to achieve this goal. As a basic study to predict the intrusion of seawater in coastal phreatic aquifers, the coupled flow and solute transport analysis was conducted by use of the 3-D finite element code, SWICHA. In order to understand how the location and the shape of freshwater-seawater transition zone were affected by the boundary conditions and hydrogeologic variables, parametric study was carried out.

Temporal Variations of Submarine Groundwater Discharge (SGD) and SGD-driven Nutrient Inputs in the Coastal Ocean of Jeju Island (제주도 연안에서 해저 지하수 및 지하수 기원 영양염류 유입량의 시간적 변화)

  • Hwang, Dong-Woon;Koh, Byoung-Seol
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • 제17권4호
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    • pp.252-261
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    • 2012
  • To determine the temporal variations of submarine groundwater discharge (SGD) and SGD-driven nutrients inputs, we measured the seepage rate and the nutrient concentrations of pore water/groundwater in Bangdu Bay of Jeju Island at two and three month intervals from September 2009 to September 2010. The seepage rate of groundwater ranged from 0 to 330 cm/day (average ~170 cm/day) during the five sampling periods, which increased sharply from high tide to low tide due to changes in hydraulic pressure gradient between water table in land and water sea level in the coastal ocean by the tidal cycles. The submarine inputs of groundwater were also relatively higher in summer than in winter. The nutrient fluxes from SGD were about 90~100%, 70~95%, and 65~100% of the total input (except from open ocean waters) for dissolved inorganic nitrogen (DIN), phosphorus (DIP), and silicate (DSi), respectively, potentially supporting about 0.9~33 g $carbon/m^2/day$ of new primary production in Baugdu Bay. Thus, our study suggests that SGD-driven nutrients may play an important role in the eutrophication and biological production in the coastal ocean of Jeju Island.