제주도 지역별 지하수위 변동 요인에 대한 고찰

정지호,박재성,고은희,박원배,정진아 대한지질공학회 2022 지질공학 Vol.32 No.2

This study evaluated the hydraulic factors contributing to the decreasing groundwater levels across Jeju island. Time-series data for groundwater level, precipitation, and groundwater usage and information on land use were acquired, and the correlations among them were analyzed to evaluate the causes of the decreasing groundwater. The effects of precipitation and groundwater usage on the fluctuations of groundwater level were quantified using response surface analysis and sensitivity analysis, and methods for groundwater quantity management by region were proposed. The results showed that the rate of groundwater decrease in the western region was larger than that in the eastern region. For the eastern region, the influence of precipitation was large and the rate of decrease in the groundwater level was relatively small. The geological formation of this part of the island and continuous seawater intrusion suggest that although the absolute amount of groundwater extracted for use was large, the decrease in the groundwater level was not seen to be great due to an increase in pressure by seawater intrusion. Overall, precipitation and groundwater usage had the greatest effect on the amount of groundwater in the western region, and thus their data would be most useful for informing groundwater management, whereas other factors (e.g., sea level and the location of the freshwater-seawater transition zone) must be considered when understanding Jeju’s eastern region. As the characteristics of groundwater level fluctuations in the eastern and western regions are distinct, an optimal management plan for each region should be proposed to ensure the efficient management of groundwater quantity. 본 연구에서는 제주도 전역에 대해 발생하고 있는 지하수위 저하 현상의 원인을 평가하기 위한 분석이 실시되었다. 이를 위해 지하수위, 강수, 지하수 이용량 시계열 자료 및 토지 이용에 대한 정보를 취득하고 이들 간의 상관성을 분석하여 지하수위 저하 원인을 파악하고자 하였다. 반응표면 분석법 및 민감도 분석법을 이용하여 지역별 강수 및 지하수 이용량 변화가 지하수위 변동에 미치는 영향력을 정량화하였으며, 획득된 영향력 지도 및 다양한 공간통계 자료를 비교 분석함으로써 지하수위 하강 원인을 분석하고, 이를 통해 지역별 지하수량 관리를 위한 방안을 고찰하였다. 분석 결과, 서부지역의 지하수위 하강률이 동부지역에 비하여 큰 것으로 나타났으며, 특히, 서부지역은 지하수 이용량이 지하수위 변동에 큰 영향력을 가지는 것으로 나타났다. 반면, 동부지역의 경우, 지하수위 변동에 대한 강수의 영향력이 크게 나타났으며, 지하수위 저하율은 상대적으로 작게 나타나고 있다. 하지만, 강수량 대비 지하수 이용량의 증가율이 서부지역에 비하여 빠르게 발생하고 있고, 동부지역의 넓은 기저 지하수대 형성 양상 및 해수 침투가 지속적으로 보고되고 있는 점에서 미루어 보았을 때, 지하수 이용량이 증가함에 따라 지하수의 절대량은 줄어들었음에도 염수압으로 인하여 지하수위 저하가 크지 않은 것처럼 나타났을 가능성이 있는 것으로 평가되었다. 이를 종합하였을 때, 서부지역에 대한 지하수량 관리를 위해서는 강수 및 지하수 이용량에 대한 정보가 필수적으로 고려되어야 할 것으로 판단되며, 동부지역은 이 외 광역적인 수리학적 스트레스를 가할 수 있는 요소(해수면 변동, 염수-담수 경계 위치, 등)에 대한 면밀한 연구가 필요할 것으로 판단된다. 또한, 동부 및 서부지역의 지하수위의 변동 특징이 비교적 뚜렷하게 구분됨에 따라 보다 효율적 지하수량 관리를 위해 각 지역에 최적화된 관리 방안이 제시 및 적용되어야 할 것으로 판단된다.

제주지역 지하수 적정허가량의 합리적 산정방안

박원배,강봉래 제주학회 2019 濟州島硏究 Vol.51 No.-

Jeju has introduced a groundwater-intake permit system since 2007 in order to systematically manage the groundwater permission volume. As the end of the December 2016, the admitted groundwater permits amounted to 1,563 thousand ㎥/day, which reached 88% of Jeju’s total sustainable use of 1,768 ㎥/day. However, until recently, the estimation of proper groundwater permission was calculated according to situations such as the amount of sewage sludge generated at the development site or area. There are 2-3 times the difference in each place of business. In this study, we analyzed the groundwater usage data over 4 years from 2013 to 2016, to estimate proper groundwater permission volume in four major industries with the largest amount of groundwater use, golf courses, lodging industries, personal service industries and residential facilities. As a result, in this study, we have developed an equation for estimating the permissible volume of groundwater for golf courses, residential facilities, individual service industries such as bathrooms and lodging businesses. This equation can be used in granting permission for groundwater development, use, and extension. However, groundwater wells for public-waterworks and agriculture- are analyzed to operate more than 90% of the allowded amount when drought occurs. If a drought continues more than 3 months, it is expected that there will be a problem in the supply of water. Therefore, improvement of the water supply system should be made first. 제주도에서는 지하수 허가량을 체계적으로 관리하기 위해 2007년부터 지하수 취수 허가량 제도를 도입하여 운영하고 있다. 2016년 12월말 현재 지하수 허가량은 1,563천㎥/일으로 제주도 지하수 지속이용가능량 1,768천㎥/일의 88%에 이르고 있다. 그러나 최근까지 지하수 적정허가량 산정은 개발 사업장의 하수도 발생량 또는 면적 등 상황에 따라 산정하고 있어 사업장별로 2~3배의 차이가 발생하고 있는 실정이다. 본 연구에서는 지하수 적정관리를 위해 2013~2016년까지 4년간 지하수 이용량 검침 자료를 분석한 후, 지하수 이용량이 많은 주요 4개 업종인 골프장, 숙박업, 개인서비스업, 주거시설을 대상으로 지하수 적정허가량 산정방안을 제시하고자 수행하였다. 그 결과, 본 연구에서 개발된 골프장, 숙박업용, 목욕장 등 개인서비스업용, 주거시설용 지하수 허가량 추정식은 지하수 개발․이용허가 및 연장허가 시 활용할 수 있을 것으로 판단된다. 그러나 공공 지하수 관정인 상수도용과 농업용 지하수인 경우 가뭄이 발생할 경우 이용률이 허가량의 90% 이상 가동하고 있는 것으로 분석되고 있어, 3개월 이상의 가뭄이 발생할 경우 상수도 공급에 차질이 발생할 우려가 많을 것으로 예상되기 때문에 상수도 공급체계 개선이 우선적으로 이루어져야 할 것으로 사료된다.

Remediation of Contaminated Groundwater: Change of Paradigm for Sustainable Use

Lee, Jin-Yong,Lee, Kang-Kun Korean Society of Soil and Groundwater Environment 2013 지하수토양환경 Vol.18 No.6

Groundwater development and use have been increasing in Korea causing frequent occurrences of related hazards such as groundwater level decline, land subsidence, and groundwater contamination. To tackle these groundwater problems, central and local governments have set-up and maintained many groundwater monitoring programs such as the National Groundwater Monitoring Network and the Groundwater Quality Monitoring Network, which collect very valuable data on the overall status of domestic groundwater to aid proper groundwater management. However, several problems mainly related to the remediation of contaminated groundwater remain unresolved. Recently, there have been some incidents related to the contamination of groundwater, and these have drawn the concern of the Korean people. Although groundwater contamination has been investigated in detail, actual groundwater remediation work has not yet been implemented. The remediation of the contaminated groundwater must begin immediately in order to sustain the eco-system service of clean groundwater and enhance the welfare of the Korean people.

지속가능한 지하수의 이용을 위한 우리나라 지하수 관련 법제의 과제

이준서 ( Jun Seo Lee ) 한국법정책학회 2015 법과 정책연구 Vol.15 No.1

Exploiting groundwat r r quires extreme caution, in part because nature, once deformed or destroyed, is nearly impossible to restor to its original state. Of course, a precautionary approach necessarily entail law and regulation. There are a lot of legislations related to groundwater, such as Groundwater Act, Hot Spring Act, Drinking Water Management Act, and so on, however, there are many flaws in our groundwater legislations. Recently groundwater has taken a considerable portion of whole water resource. In order to maintain high-quality groundwater, the government should devise a comprehensive policy and improve law for the sustainable development of groundwater. I suggest the following: clear criteria and definition of groundwater pollution and bad quality; management method considering characteristics of groundwater; breakaway from development-oriented policy. In foreign countries, there is enactments which is the ownership of river separated from river site and it is recognized ground water as public water, therefore it suggests that we also need to separate groundwater from a right of landowner and to recognize groundwater as public water. nlike other laws, there are provisions about development as many as those about preservation in the Groundwater Act. As we realize that groundwater is a limited resource and it cannot be monopolized by landowner, we need to look to ways of improving our legislations for oroundwater as a public water resource.

Distribution characteristics and processes along flow paths of shallow groundwater in the Tan-Lu fault zone in Anhui province, China

Dejian Wang,Jiazhong Qian,Weidong Zhao,Xiaoliang Hou,Wei Wang,Lei Ma 한국지질과학협의회 2022 Geosciences Journal Vol.26 No.4

To disclose the distribution characteristics, the situation of flow and storage, and processes along flow paths of shallow groundwater in Tan-Lu fault zones, nine hundred and seven groundwater table elevations data and one hundred hydrochemical samples of shallow groundwater were taken from the Tan-Lu fault zone in Anhui province to analyze the characteristic of groundwater distribution. The geographic information system (GIS) method was used to analyze the spatial distribution characteristics of groundwater tables, total dissolved solids (TDS) and chloride ion (Cl−). Geophysical prospecting, drilling material and regional hydrogeological survey were utilized to disclose groundwater storage and flow regime in the fault zone. The results show that the Tan-Lu fault zone in Anhui province has controlled groundwater flow into the Jiashan basin, Hefei basin, Chaohu area and Qianshan basin, which developed from north to south in this area. Groundwater in theses basins have recharged from surrounding areas to form a water storage space. Geophysical prospecting and drilling technology revealed that the Tan-Lu fault zone provided a flow channel and storage space for groundwater. Faults provide preferential channels in some areas for the groundwater flow and circulation, eventually deep hot-water flows upward and discharges in the form of hot-springs. The identification of the groundwater flow pathway can help to provide a reliable scientific basis for regional spatial development and utilization of groundwater resources.

Remediation of Contaminated Groundwater:Change of Paradigm for Sustainable Use

이진용,이강근 한국지하수토양환경학회 2013 지하수토양환경 Vol.18 No.6

Groundwater development and use have been increasing in Korea causing frequent occurrences of related hazards such as groundwater level decline, land subsidence, and groundwater contamination. To tackle these groundwater problems,central and local governments have set-up and maintained many groundwater monitoring programs such as the National Groundwater Monitoring Network and the Groundwater Quality Monitoring Network, which collect very valuable data on the overall status of domestic groundwater to aid proper groundwater management. However, several problems mainly related to the remediation of contaminated groundwater remain unresolved. Recently, there have been some incidents related to the contamination of groundwater, and these have drawn the concern of the Korean people. Although groundwater contamination has been investigated in detail, actual groundwater remediation work has not yet been implemented. The remediation of the contaminated groundwater must begin immediately in order to sustain the ecosystem service of clean groundwater and enhance the welfare of the Korean people.

Groundwater Dynamics and Balance in the Western Part of Greater Kushtia District of Bangladesh

M. Nozibul Haque,Mumnunul Keramat,Shamsuddin Shahid,Morteza Mohsenipour,Xiao-Jun Wang 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.5

Groundwater dynamics and balance have been studied for the assessment of groundwater abstraction status in the western part of grater Kushtia district, Bangladesh using data from 28 groundwater level monitoring wells, 180 lithologs, and one rainfall station for the period 2001-2007. The groundwater levels in the study area were found to vary at a depth between 0.0 m and 9.34 m. During peak season of groundwater abstraction (pre-monsoon), the maximum and minimum groundwater level with respect to mean sea level (MSL) were found to vary from 9.36 to 11.3 m and 2.3 to 4.9 m, respectively, whereas in post-monsoon these values were found to vary from 13.2 to 15.6 m and 7.6 to 9.6 m, respectively. The groundwater flow in the area was driven by topography, directed from the northwest to the southeast. This study revealed a declining trend in groundwater table both in pre- and post-monsoon seasons in the area. It has also been noticed that the rate of declination is increasing with time. The volumetric analysis of groundwater also showed a net negative balance, which indicates overexploitation of groundwater. The study concluded that the unsustainable utilization of groundwater resources in the study area has caused depletion in groundwater table.

Characterization of Groundwater Chemistry and Fluoride in Groundwater Quality Monitoring Network of Korea

한지원 한국지구과학회 2021 한국지구과학회지 Vol.42 No.5

This study presents the data analysis results of groundwater chemistry and the occurrence of fluoride in groundwater obtained from the groundwater quality monitoring network of Korea. The groundwater data were collected from the National Groundwater Information Center and censored for erratic values and charge balance (±10%). From the geochemical graphs and various ionic ratios, it was observed that the Ca-HCO3 type was predominant in Korean groundwater. In addition, water-rock interaction was identified as a key chemical process controlling groundwater chemistry, while precipitation and evaporation were found to be less important. According to a non-parametric trend test, at p=0.05, the concentration of fluoride in groundwater did not increase significantly and only 4.3% of the total groundwater exceeded the Korean drinking water standard of 1.5 mg/L. However, student t-tests revealed that the fluoride concentrations were closely associated with the lithologies of tuff, granite porphyry, and metamorphic rocks showing distinctively high levels. This study enhances our understanding of groundwater chemical composition and major controlling factors of fluoride occurrence and distribution in Korean groundwater.

Natural analogue monitoring to estimate the hydrochemical change of groundwater by the carbonating process from the introduction of CO₂

Choi, Hanna,Woo, Nam Chil Elsevier 2018 Journal of hydrology Vol.562 No.-

<P><B>Abstract</B></P> <P>This study monitored four geothermal groundwater (TW) wells (Suanbo, Yuseong, Deoksan, and Seokmodo), four carbonated groundwater (CW) springs (Chojeong, Bugang, Shin, and Bangadari) and shallow groundwater (GW) in order to interpret the carbonating process from the seepage of CO<SUB>2</SUB>. In a bid to figure out the carbonated reservoir where CO<SUB>2</SUB> mixing occurs, the CW samples represent the condition of the final carbonated water as natural analogues. The initial fresh water can be assumed to be the following depth: the deep aquifer with 300–700 m below the surface level (b.s.l) and the shallow aquifer to be below 300 m b.s.l. The pairs of hydrogen (δ2H) and oxygen (δ18O) isotopes indicated that all the groundwater samples had been recharged from meteoric water at various heights. The Δ14C data of the TW samples present residence time from 1980 ± 30 to 6400 ± 30 years BP (before present) and the δ13C data of dissolved inorganic carbon in the CW distributed from −3 to −10‰ range implying the mantle degassing effects. Regardless of seasonal variations, the TW samples and the CW samples were shown to be the Na-HCO3 type and the Ca-HCO3 type, respectively, indicating these aquifers remain in closed conditions. Based on the chalcedony geothermometer results, the carbonated reservoir of the CW samples were estimated to range between 43.08 and 83.13 °C, which were paired with the average temperature of the TW sites. In turn, the reservoir depth estimations taken by multiplying temperatures by geothermal gradients were estimated to range between 1.34 km and 3.90 km. Meanwhile, the in-situ data of the CW sites were estimated to range between 3.8 and 18.7 °C and between 263.7 and 488.7 mV of redox potential of oxidizing condition, which means there are the possibilities of shallow carbonated reservoir. In order to delineate the hydrochemical changes of the fresh groundwater during carbonation at a deep reservoir and a shallow reservoir, the PHREEQC modeling was conducted with 0.0001–10 mol L−1 of CO<SUB>2</SUB> mixing. As the CO<SUB>2</SUB> concentrations increased, the TW and the GW displayed different ionic variations but the inland groundwater identically moved to the Ca-HCO3 type. The coastal TW can be reflecting the carbonation process of the coastal AZMI section, containing large quantities of salts. The carbonation of these samples is triggered by 0.01 mol L−1 of CO<SUB>2</SUB> introduced into the reservoir but it still retained the Na-Cl water type despite a Log PCO<SUB>2</SUB> of over −0.5. The study results imply that there can be deep reservoirs and shallow reservoirs responsible for developing carbonated groundwater. It will be useful to estimate hydrochemical variations of groundwater resulting from the natural-artificial CO<SUB>2</SUB> leakage.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hydrochemist of geothermal groundwater and carbonated groundwater to interpret carbonating processes as natural analogues. </LI> <LI> Carbonated reservoir depths using chalcedony geothermometer and geothermal gradient were estimated to be 1.34–3.90 km below surface level (b.s.l) in this natural analogue site. </LI> <LI> Different reaction paths of deep and shallow groundwater inferred using the PHREEQC. </LI> </UL> </P>

Considering the effect of groundwater on bioretention using the Storm Water Management Model

Kim, Hwansuk,Mallari, Kristine Joy B.,Baek, Jongrak,Pak, Gijung,Choi, Hyun Il,Yoon, Jaeyoung Elsevier 2019 Journal of environmental management Vol.231 No.-

<P><B>Abstract</B></P> <P>The Storm Water Management Model (SWMM), with its recently released low impact development (LID) module, is among several models used for the performance evaluation of LID facilities in reducing runoff and pollutants. Modeling is often difficult because of the variety of factors affecting the LID system. Among these factors, the effect of groundwater can be important in the LID modeling results due to the possibility of its interaction with LID. In this study, the performance of the SWMM-LID controls in predicting runoff from bioretention cells was evaluated for a site under groundwater influence. In addition, for considering the groundwater effect in the model, this study explores the utility of the SWMM groundwater model in predicting runoff under groundwater influence. Runoff from the considered watershed draining into the bioretention cells was well-simulated with very favorable performance statistic values (r<SUP>2</SUP> = 0.96, NSE = 0.94, % difference = 2.76). However, comparison of simulated with observed runoff from bioretention cells produced weaker statistical values (r<SUP>2</SUP> = 0.69, NSE = 0.65, % difference = 18.22), which is thought to be due to the presence of events affected by groundwater interference. Removal of these events and recalibration were able to improve the overall results, suggesting that the influence of groundwater should be taken into account for better LID modeling of the study site. In order to consider the groundwater influence, the SWMM groundwater model was used in tandem with LID controls to provide an additional influent source to bioretention cells. This resulted in a good fit for two events which were thought to be impacted by groundwater (events in which outflow exceeded inflow) and overall better performance (r<SUP>2</SUP> = 0.95, NSE = 0.95, % difference = 3.49) compared to the results obtained by using only LID controls. In conclusion, the SWMM groundwater model can help deal with groundwater-impacted events. However, for better representation of the phenomenon, the LID module itself needs to be improved to account for direct interaction with groundwater.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We calibrated and validated a bioretention system under groundwater influence using SWMM LID control. </LI> <LI> Data used for calibration and validation was screened from International Stormwater BMP Database. </LI> <LI> The effect of groundwater was found to be negative on the outflow modeling results for the events with high antecedent moisture condition. </LI> <LI> The use of the SWMM's groundwater model was able to represent well the impact of groundwater on the outflow from bioretention. </LI> </UL> </P>