• Title/Summary/Keyword: groundwater flow paths

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Distribution of Rare Earth Elements and Their Applications as Tracers for Groundwater Geochemistry - A Review

  • Hwang, Heejin;Nyamgerel, Yalalt;Lee, Jeonghoon
    • Journal of the Korean earth science society
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    • v.42 no.4
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    • pp.383-389
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    • 2021
  • Several studies investigating the behavior and environmental distribution of rare earth elements (REEs) have been reviewed to determine the geochemical processes that may affect their concentrations and fractionation patterns in groundwater and whether these elements can be used as tracers for groundwater-rock interactions and groundwater flow paths in small catchments. Inductively coupled plasma-mass spectrometry (ICP-MS), equipped with an ultrasonic nebulizer and active-film multiplier detector, is routinely used as an analytical technique to measure REEs in groundwater, facilitating the analysis of dissolved REE geochemistry. This review focuses on the distribution of REEs in groundwater and their application as tracers for groundwater geochemistry. Our review of existing literature suggests that REEs in ice cores can be used as effective tracers for atmospheric particles, aiding the identification of source regions.

Development and Application of Streamline Analysis Method (유선 분석법의 개발 및 적용)

  • Kim Tae Beom;Lee Chihyung;Cheong Jae-Yeol
    • Journal of Soil and Groundwater Environment
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    • v.28 no.6
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    • pp.9-15
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    • 2023
  • In order to properly evaluate the spatio-temporal variations of groundwater flow, the data obtained in field experiments should be corroborated into numerical simulations. Particle tracking method is a simple simulation tool often employed in groundwater simulation to predict groundwater flow paths or solute transport paths. Particle tracking simulations visually show overall the particle flow path along the entire aquifer, but no previous simulation studies has yet described the parameter values at grid nodes around the particle path. Therefore, in this study, a new technical approach was proposed that enables acquisition of parameters associated with particle transport in grid nodes distributed in the center of the particle path in groundwater. Since the particle tracking path is commonly referred to as streamline, the algorithm and codes developed in this works designated streamline analysis method. The streamline analysis method can be applied in two-dimensional and three-dimensional finite element or finite difference grid networks, and can be utilized not only in the groundwater field but also in all fields that perform numerical modeling.

GROUNDWATER RECHARGE ESTIMATION USING ARCGIS-CHLORIDE MASS BALANCE APPROACH

  • Lee Ju Young;Krishinamurshy Ganeshi
    • Water Engineering Research
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    • v.6 no.1
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    • pp.31-38
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    • 2005
  • Groundwater recharge is defined in an addition of water to groundwater reservoir. Recently, many people have been moving to the Edwards aquifer and urban and agricultural industry have been expending. Hydrologists and water planning managers concern about insufficient groundwater amounts and irrigation water price variability. In this paper, I focus on estimates of local recharge volumes and quantify preferential flow through GIS technique. Chloride Mass Balance (CMB) and hydrochemical components have been widely applied to recharge rate and evaluate flow paths. The CMB method is based on relationship between wet-dry chloride deposition data and Rainfall data. These data are manipulated using ArcGIS. Especially, hydrochemical concentration distribution is good index for groundwater residence times or flow paths such as $[Mg^{2+}]/[Ca^{2+}],[Cl]$ and log$([Ca^{2+}]+[Mg^{2+}])/[Na^+]$. Well information such as hydrological-hydrochemical data are imported into ArcGIS and manipulated by interpolation techniques. For each potentiometric surface and water quality, point data are converted to spatial data through each Kriging and Inverse Distance Weighted (IDW) techniques.

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Underground temperature survey for the study of shallow groundwater flow system

  • Okuyama Takehiko;Kuroda Seiichiro;Nakazato Hiroomi;Natsuka Isamu
    • 한국지구물리탐사학회:학술대회논문집
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    • 2003.11a
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    • pp.690-694
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    • 2003
  • Groundwater preferentially flows through sediment layers with high permeability such as colluvium. Its flow paths are called groundwater vein streams. An underground temperature survey is a method to locate vein streams by underground temperature anomalies associated with flowing groundwater. A groundwater flow system near an irrigation reservoir located in the upper part of a landslide block was surveyed with this method. After a geomembrane lining was installed in the reservoir, the total cross-sectional area of the vein streams in the aquifer decreased to as little as 0.35 times that before installation of the liner. A change in groundwater quality also indicated that the mixing of groundwater with leaked water from the reservoir stopped after installation of the lining.

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A Numerical Model for Steady State Groundwater Flow Near a Radioactive Waste Repository (방사성폐기물 처분장 주변에서 정상상태의 지하수 수치 모델 개발)

  • Suh, Kyung Suk;Lee, Han Soo;Han, Kyung Won
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.9 no.4
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    • pp.103-112
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    • 1989
  • A numerical model for Steady state groundwater flow has been established to understand the groundwater flow phenomena near a radioactive waste repository. The integrated finite difference method based on a network composed of nodes and members was applied to investigate groundwater flow in homogeneous, heterogeneous and layered media. Its numerical solution was in good agreement with analytic solution. Physical phenomena associated in the groundwater flow depending on both hydraulic characteristics and effects of fractured zone were also investigated. A method by which feasible groundwater flow paths can be identified was developed. This method used the composite network for the geologic media near a repository and the direction of computed groudwater velocity. Groundwater velocity and travel time were predicted for the possible pathway form a repository to a biosphere.

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Groundwater Ages and Flow Paths at a Coastal Waste Repository Site in Korea, Based on Geochemical Characteristics and Numerical Modeling

  • Cheong, Jae-Yeol;Hamm, Se-Yeong;Koh, Dong-Chan;Lee, Chung-Mo;Ryu, Sang Min;Lee, Soo-Hyoung
    • The Journal of Engineering Geology
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    • v.26 no.1
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    • pp.1-13
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    • 2016
  • Groundwater flow paths and groundwater ages at a radioactive waste repository located in a coastal area of South Korea were evaluated using the hydrochemical and hydrogeological characteristics of groundwater, surface water, rain water, and seawater, as well as by numerical modeling. The average groundwater travel time in the top layer of the model, evaluated by numerical modeling and groundwater age (34 years), approximately corresponds to the groundwater age obtained by chlorofluorocarbon (CFC)-12 analysis (26-34 years). The data suggest that the groundwater in wells in the study area originated up-gradient at distances of 140-230 m. Results of CFC analyses, along with seasonal variations in the δ18O and δD values of groundwater and the relationships between 222Rn concentrations and δ18O values and between 222Rn concentrations and δD values, indicate that groundwater recharge occurs in the summer rainy season and discharge occurs in the winter dry season. Additionally, a linear relationship between dissolved SiO2 concentrations and groundwater ages indicates that natural mineralization is affected by the dilution of groundwater recharge in the rainy summer season.

Validation of a new magnetometric survey for mapping 3D subsurface leakage paths

  • Park, DongSoon;Jessop, Mike L.
    • Geosciences Journal
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    • v.22 no.6
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    • pp.891-902
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    • 2018
  • Techniques for more reliable detection of 3D subsurface flow paths are highly important for most water-related geotechnical projects. In this case study, a magnetometric resistivity method with a new approach and state-of-the-art technology ("Willowstick survey") was applied to the testbed dam (YD dam) site, and its applicability was validated by geotechnical investigation techniques including borehole drilling and sampling, Lugeon test, flow direction and velocity test, and seismic tomography. In addition to the magnetometric survey, a 3D electrical resistivity survey was performed independently and the results were compared and discussed. The electrical resistivity survey was effective in detecting groundwater levels, but it was limited in mapping leakage paths. On the other hand, the Willowstick magnetometric survey effectively detected geologic weaknesses (e.g., fault fracture) and potential leakage paths of the dam site foundation rocks. The results of this research are expected to be effective for water infrastructures where leakage is an important issue.

Complexity of Groundwater Flow System in a Site Reflected in the Fluctuations of Groundwater Level and Temperature (지하수위와 수온 변동에 나타난 부지 규모 지하수 흐름장의 복잡성)

  • Jonghoon Park;Dongyeop Lee;Nam C. Woo
    • Economic and Environmental Geology
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    • v.55 no.6
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    • pp.563-570
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    • 2022
  • This study was objected to show the complexity of groundwater flow system in a site-scale area as a design parameter of the groundwater monitoring network for early detection of pollutant leakage from a potential source of groundwater contamination (e.g., storage tank). Around the tanks, three monitoring wells were installed at about 22~25 m deep and groundwater level and temperature had been monitored for 22 months by 2-minute interval, and then compared with precipitation and temperature data from nearby weather station. Annual variation of groundwater level and its response to precipitation event, variation of groundwater temperature and delayed response to that of atmospheric temperature indicate the complexity of groundwater flow and flow paths even in the relatively small area. Thus, groundwater monitoring network for early detection of contaminant leakage should be designed with full consideration of the complexity of groundwater flow system, identified from the detailed hydrogeological investigation of the site.

Simulation of Groundwater Flow in Fractured Porous Media using a Discrete Fracture Model (불연속 파쇄모델을 이용한 파쇄 매질에서의 지하수 유동 시뮬레이션)

  • Park, Yu-Chul;Lee, Kang-Kun
    • Economic and Environmental Geology
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    • v.28 no.5
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    • pp.503-512
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    • 1995
  • Groundwater flow in fracture networks is simulated using a discrete fracture (DF) model which assume that groundwater flows only through the fracture network. This assumption is available if the permeability of rock matrix is very low. It is almost impossible to describe fracture networks perfectly, so a stochastic approach is used. The stochastic approach assumes that the characteristic parameters in fracture network have special distribution patterns. The stochastic model generates fracture networks with some characteristic parameters. The finite element method is used to compute fracture flows. One-dimensional line element is the element type of the finite elements. The simulation results are shown by dominant flow paths in the fracture network. The dominant flow path can be found from the simulated groundwater flow field. The model developed in this study provides the tool to estimate the influences of characteristic parameters on groundwater flow in fracture networks. The influences of some characteristic parameters on the frcture flow are estimated by the Monte Carlo simulation based on 30 realizations.

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Groundwater Flow Characterization in the Vicinity of the Underground Caverns by Groundwater Level Changes (지하수위 변화에 따른 지하공동 주변의 지하수 유동특성 해석)

  • 강재기;양형식;김경수;김천수
    • Tunnel and Underground Space
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    • v.13 no.6
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    • pp.465-475
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    • 2003
  • Groundwater inflow into the caverns constructed in fractured rock mass was simulated by numerical modeling, NAPSAC (DFN, discrete fracture network model) and NAMMU (CPM, continuous porous media model), a finite-element software package for groundwater flow in 3D fractured media developed by AEA Technology, UK. The input parameters for modeling were determined on surface fracture survey, core logging and single hole hydraulic test data. In order to predict the groundwater inflow more accurately, the anisotropic hydraulic conductivity was considered. The anisotropic hydraulic conductivities were calculated from the fracture network properties. With a minor adjustment during model calibration, the numerical modeling is able to reproduce reasonably groundwater inflows into cavern and the travel length and times to the ground surface along the flow paths in the normal, dry and rainy seasons.