• Title, Summary, Keyword: groundwater flow

Search Result 930, Processing Time 0.047 seconds

Analysis of Groundwater Flow Characterstics and Hydraulic Conductivity in Jeju Island Using Groundwater Model (지하수 모델을 이용한 제주도 지하수 유동특성 및 수리전도도 분석)

  • Kim, Min-Chul;Yang, Sung-Kee
    • Journal of Environmental Science International
    • /
    • v.28 no.12
    • /
    • pp.1157-1169
    • /
    • 2019
  • We used numerical models to reliably analyze the groundwater flow and hydraulic conductivity on Jeju Island. To increase reliability, improvements were made to model application factors such as hydraulic watershed classification, groundwater recharge calculation by precipitation, hydraulic conduction calculation using the pilot point method, and expansion of the observed groundwater level. Analysis of groundwater flow showed that the model-calculated water level was similar to the observed value. However, the Seogwi and West Jeju watersheds showed large differences in groundwater level. These areas need to be analyzed by segmenting the distribution of the hydraulic conductivity. Analyzing the groundwater flow in a sub watershed showed that groundwater flow was similar to values from equipotential lines; therefore, the reliability of the analysis results could be improved. Estimation of hydraulic conductivity distribution according to the results of the groundwater flow simulation for all areas of Jeju Island showed hydraulic conductivity > 100 m/d in the coastal area and 1 - 45 m/d in the upstream area. Notably, hydraulic conductivity was 500 m/d or above in the lowlands of the eastern area, and it was relatively high in some northern and southern areas. Such characteristics were found to be related to distribution of the equipotential lines and type of groundwater occurrence.

Preliminary results of groundwater flow simulation for high level radioactive disposal in Yu-seong area

  • Park kyung-woo;Cho sung-il;Kim chun-soo;Kim kyung-su;Lee kang-keun
    • Proceedings of the Korean Radioactive Waste Society Conference
    • /
    • /
    • pp.253-257
    • /
    • 2005
  • This research aims to demonstrate the regional and site scale groundwater flow simulation for the high level radioactive disposal research site in Yu-seong. We used the Modflow by a finite difference method for groundwater flow simulation, and Modpath module in Modflow package for particle tracking simulation. The range of numerical domain for regional groundwater flow model is $16.32km{\times}20.16km$. And, the depth of numerical domain was expanded to 6,000m. The area of numerical domain for the site scale groundwater flow simulation is $1.6km{\times}1.6km$. Since 2005, the underground research tunnel(URT) is being constructed at KAERI(Korea Atomic Energy Research Institute) site. In the site scale groundwater flow model, the groundwater flow around the KAERI site is simulated. And the change of groundwater level with tunnel excavation is also predicted.

  • PDF

Development of a Transient Groundwater Flow Model in Pyoseon Watershed of Jeju Island: Use of a Convolution Method (컨벌루션 기법을 이용한 제주도 표선유역 부정류 지하수 흐름 모델 개발)

  • Kim, Seung-Gu;Koo, Min-Ho;Chung, Il-Moon
    • Journal of Environmental Science International
    • /
    • v.24 no.4
    • /
    • pp.481-494
    • /
    • 2015
  • Groundwater level hydrographs from observation wells in Jeju island clearly illustrate distinctive features of recharge showing the time-delaying and dispersive process, mainly affected by the thickness and hydrogeologic properties of the unsaturated zone. Most groundwater flow models have limitations on delineating temporal variation of recharge, although it is a major component of the groundwater flow system. Recently, a convolution model was suggested as a mathematical technique to generate time series of recharge that incorporated the time-delaying and dispersive process. A groundwater flow model was developed to simulate transient groundwater level fluctuations in Pyoseon area of Jeju island. The model used the convolution technique to simulate temporal variations of groundwater levels. By making a series of trial-and-error adjustments, transient model calibration was conducted for various input parameters of both the groundwater flow model and the convolution model. The calibrated model could simulate water level fluctuations closely coinciding with measurements from 8 observation wells in the model area. Consequently, it is expected that, in transient groundwater flow models, the convolution technique can be effectively used to generate a time series of recharge.

Reliability approach to three-dimensional groundwater flow analysis in underground excavation (지하굴착지반에서의 3차원 지하수흐름에 관한 신뢰성해석)

  • Jang, Yeon-Soo;Kim, Hong-Seok;Park, Joon-Mo
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • /
    • pp.988-997
    • /
    • 2006
  • In this paper, a reliability-groundwater flow program is developed by coupling the 3-D finite element numerical groundwater flow program with first and second order reliability program. The numerical groundwater program developed called DGU-FLOW is verified by solving the examples of groundwater flow through the underground excavation and comparing the results with those of commercial MODFLOW 3D programs. Reliability routine of the program is also verified by comparing the probability of failure of the flow model from FORM/SORM with that of Monte-Carlo Simulation. The difference of out-flux and total head calculated near the bottom of the excavation using the deterministic 3D groundwater flow and the commercial programs was negligible. The reliability analysis of the groundwater flow showed that the probability of failure from the first and second order reliability method are quite close that of Monte-Carlo Simulation. Therefore, the developed program is considered effective for analyzing the groundwater flow with uncertainty in hydraulic conductivity of the soils.

  • PDF

3 Dimensional Numerical Simulation for the Closed Loop Heat Pump System Using TOUGH2 (TOUGH2를 이용한 폐쇄형 지열펌프 시스템의 3차원 모델링 연구)

  • Kim, Seong-Kyun;Bae, Gwang-Ok;Lee, Kang-Kun
    • 한국신재생에너지학회:학술대회논문집
    • /
    • /
    • pp.36-39
    • /
    • 2006
  • To evaluate the effect of groundwater flow on the outlet temperature of a geothermal heat pump, 3 dimensional numerical simulations are performed considering both groundwater flow and pipe flow in the U-tube using TOUGHS, The present study involved the following 4 simulation cases (1) no groundwater flow, (2) slow groundwater flow (hydraulic conductivity: $1.0{\times}10^{-9}m/s)$, (3) fast groundwater flow (hydraulic conductivity, $1.0{\times}10^{-7}m/s$), and (4) groundwater flow varying with the depth (hydraulic conductivity: $1.0{\times}10^{-7}-1.0{\times}10^{-10}m/s$). The effect of groundwater flow on the outlet temperature is significant where hydraulic conductivity of aquifer is $1.0{\times}10^{-7}m/s$. Where hydraulic conductivity of aquifer is $1.0{\times}10^{-10}m/s$, however, that effect is negligible.

  • PDF

Source Identification of Nitrate contamination in Groundwater of an Agricultural Site, Jeungpyeong, Korea

  • 전성천;이강근;배광옥;정형재
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
    • /
    • /
    • pp.63-66
    • /
    • 2003
  • This study applied a hydrogeological field survey and isotope investigation to identify source locations and delineate pathways of groundwater contamination by nitrogen compounds. The infiltration and recharge processes were analyzed with groundwater-level fluctuation data and oxygen-hydrogen stable isotope data. The groundwater flow pattern was investigated through groundwater flow modeling and spatial and temporal variation of oxygen isotope data. Based on the flow analysis and nitrogen isotope data, source types of nitrate contamination in groundwater are identified. Groundwater recharge largely occurs in spring and summer due to precipitation or irrigation water in rice fields. Based on oxygen isotope data and cross-correlation between precipitation and groundwater level changes, groundwater recharge was found to be mainly caused by irrigation in spring and by precipitation at other times. The groundwater flow velocity calculated by a time series of spatial correlations, 231 m/yr, is in good accordance with the linear velocity estimated from hydrogeologic data. Nitrate contamination sources are natural and fertilized soils as non-point sources, and septic and animal wastes as point sources. Seasonal loading and spatial distribution of nitrate sources are estimated by using oxygen and nitrogen isotopic data.

  • PDF

Reviewing the Applications of Three Countries' Ground Water Flow Modeling Regulatory Guidelines to Nuclear Facilities in Korea

  • Lee, Chung-Mo;Hamm, Se-Yeong;Hyun, Seung Gyu;Cheong, Jae-Yeol;Wei, Ming Liang
    • Journal of Soil and Groundwater Environment
    • /
    • v.22 no.3
    • /
    • pp.1-9
    • /
    • 2017
  • The numerical analysis of groundwater flow is indispensable for predicting problems associated with water resource development, civil works, environmental hazards, and nuclear power plant construction. Korea lacks public regulatory procedures and guidelines for groundwater flow modeling, especially in nuclear facility sites, which makes adequate evaluation difficult. Feasible step-by-step guidelines are also unavailable. Consequently, reports on groundwater flow modeling have low-grade quality and often present controversial opinions. Additionally, without public guidelines, maintaining consistency in reviewing reports and enforcing laws is more challenging. In this study, the guidelines for groundwater flow modeling were reviewed for three countries - the United States (Documenting Groundwater Modeling at Sites Contaminated with Radioactive Substances), Canada (Guidelines for Groundwater Modelling to Assess Impacts of Proposed Natural Resource Development Activities), and Australia (Australian Groundwater Modelling Guidelines), with the aim of developing groundwater flow modeling regulatory guidelines that can be applied to nuclear facilities in Korea, in accordance with the Groundwater Act, Environmental Impact Assessment Act, and the Nuclear Safety Act.

Assessment of Groundwater Flow Modeling according to Hydraulic Conductivity Zonation in the Dae-jeong Watershed of Jeju Island (제주도 대정유역의 수리전도도 적용에 따른 지하수 모델링 결과 평가)

  • Park, Jae-Kyu;Kim, Min-Chul;Yang, Sung-Kee;Lee, Jun-ho;Kim, Yong-Seok
    • Journal of Environmental Science International
    • /
    • v.25 no.12
    • /
    • pp.1727-1738
    • /
    • 2016
  • In this study, groundwater flow was analyzed targeting Dae-jeong watershed, which exhibited the largest variations of groundwater levels at the identical elevation points among the 16 watersheds of Jeju Island. The issues of the methods applied in practice were identified and improvement plans were suggested. This groundwater-flow estimates derived by applying hydraulic conductivity values onto zones of equal topographic ground level were found to be quite different from actual measured groundwater flow. Conversely, groundwater-flow estimates that utilized hydraulic conductivity values applied onto groundwater-level equipotential lines indicated relatively lesser divergences from actual measured groundwater flow. The reliabilities of the two approaches were assessed for 60 randomly selected points on DEM (digital elevation model) maps, The method using hydraulic conductivity values applied onto groundwater-level contours turned out to be the more reliable approach for the Dae-jeong watershed in Jeju Island.

An Influence of Groundwater Flow on Performance of Closed Borehole Heat Exchangers (Part-2) (지하수류가 밀폐형 천공 지중 열교환기 성능에 미치는 영향(2))

  • Hahn, Jeongsang;Kiem, Youngseek;Lee, Juhyun;Lee, Byoungho;Hahn, Chan
    • Journal of Soil and Groundwater Environment
    • /
    • v.21 no.6
    • /
    • pp.114-127
    • /
    • 2016
  • An increase of groundwater flux in BHE system creates that ground temperature (locT) becomes lower in summer and higher in winter time. In other words, it improves significantly the performance of BHE system. The size of thermal plume made up by advection driven-flow under the balanced energy load is relatively small in contrast to the unbalanced energy load where groundwater flow causes considerable change in the size of thermal plume as well ground temperature. The ground temperatures of the up gradient and down gradient BHEs under conduction only heat transport are same due to no groundwater flow. But a significant difference of the ground temperature is observed between the down gradient and up gradient BHE as a result of groundwater flow-driven thermal interference took placed in BHE field. As many BHEs are designed under the obscure assumption of negligible groundwater flow, failure to account for advection can cause inefficiencies in system design and operation. Therefore including groundwater flow in the design procedure is considered to be essential for thermal and economic sustain ability of the BHE system.

Development of Three Dimensional Groundwater Flow Program (3차원 지하수 흐름해석 프로그램 개발에 관한 연구)

  • 박준모;장연수;김홍석;이두화
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • /
    • pp.577-584
    • /
    • 2001
  • For construction and design of tunnels, groundwater flow models are used to find the influence of groundwater to the stability of tunnels considering the geological condition around the tunnels and the materials used in tunnel linings. For the analysis of tunnel flow, some commercial programs, e.g. MODFLOW, SEEP/W etc., are used. These programs have limitations that MODFLOW could not define curved surface smoothly in three dimensional flow media and SEEP/W is the 2-dimensional flow model. In this paper, the ability of a finite element program developed for analyzing 3-dimensional groundwater flow is examined. Confined steady state groundwater flow solution in non-homogeneous media is obtained using isoparametric element with eight trilinear hexahedron nodes and is compared with the result of MODFLOW. It was found that the solution yielded a good result with the three dimensional flow studied.

  • PDF