• 한국지하수토양환경학회지:지하수토양환경
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• 제24권5호
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• pp.17-30
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• 2019

Intensive agricultural development in Mexicali valley, Baja-California, Mexico, has induced tremendous strain on the limited water resources. Agricultural water consumption in the valley mainly relies on diversions of the Colorado River, but their water supply is far less than the demand. Hence, the use of groundwater for irrigation purposes has gained considerable attention. To account for these changes, it is important to evaluate surface water and groundwater conditions based on historical water use. This study identified the effects of agricultural activities on groundwater levels and groundwater recharge in the Mexicali valley (in irrigation unit 16) by a comprehensive MODFLOW Farm process (MF-FMP) numerical modeling. The MF-FMP modeling results showed that the water table in the study area is drawn downed, more in eastern areas. The inflow-outflow analysis demonstrated that recharge to the aquifer occurs in response to agricultural supplies. In general, the model provides MF-FMP simulations of natural and anthropogenic components of the hydrologic cycle, the distribution and dynamics of supply and demand in the study area.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.299-299
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• 2017

Due to the climate changes in Korea, the numbers of both torrential rain events and drought periods have increased in frequency. Water management practice against water shortage and flooding is one of the key interesting for field crop cultivation, and groundwater often serves as an important and safe source of water to crops. Therefore, the objective of this study is to evaluate the effect of groundwater table levels on soil water content and soybean development under two different textured soils. The experiment was conducted using lysimeter located in Miryang, Korea. Two types of soils (sandy-loam and silty-loam) were used with three groundwater table levels (0.2, 0.4, 0.6m). Mean soil water content during the soybean growth period was significantly influenced by groundwater table levels. With the continuous groundwater level at 0.2m from the soil surface, soil water content was not statistically changed between vegetative and reproductive stage, but the 0.4 and 0.6m groundwater table level was significantly decreased. Lower chlorophyll content in soybean leaves was found in shallow water table treatment in earlier part of the growing season, but the chlorophyll contents were non-significant among water table treatments. Groundwater table level treatments were significantly influenced on plant available nitrogen content in surface soil. The highest N contents were observed in 0.6m groundwater table level. It is probably due to the nitrogen loss by denitrification as the result of high soil water content. The length and dry weight of primary root was influenced by groundwater level and thus the highest length and dry weight of root were observed in 0.6m water table level. This result showed that soybean root growth did not extend below the groundwater level and increased with the depth of groundwater table level. The results of this study show that the management of groundwater level can influence on soil characteristics, especially on soil water content, and it is an important practice of to reduce yield loss caused by the water stress during the crop growing season.

• 자원환경지질
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• 제39권5호
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• pp.537-554
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• 2006

유성지구 지열수의 산출 특성 및 수리적 연결성을 파악하기 위하여 2002년 3월부터 2005년 6월까지 장기 수위 관측을 실시하였다. 관측된 수위 자료를 이용하여 수위변동 주기 분석을 실시한 결과, 대부분의 관측공에서 0.5일, 1일, 7일 주기성이 확인되었다. 7일 주기성은 온천지대에서의 독특한 양수 행태로 인해 발생되는 인위적 현상으로서, 연구 지역내 관측공들의 수리적 연결성이 양호한 것을 반영하였다. 수위 영향 관계를 분석한 결과, E-W 방향성과 N-S 방향성의 지질구조가 지열수 저류체의 발달 및 지열수 유동에 중요한 규제 요소로 작용되고 있음이 확인되었다. 전반적으로 지열수의 열원과 대수층의 수리적 연결성과는 상호 연관성이 있을 것으로 해석된다.

• 자원환경지질
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• 제39권3호
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• pp.269-284
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• 2006

지하수위와 하천수위와의 상호반응과 수리적으로 다른 특성을 가지는 각 층별(실트질 모래층, 자갈모래층, 풍화대층) 반응관계를 알아보기 위하여 시계열 분석에서 많이 사용되어 온 방법인 자기상관분석과 교차상관분석방법을 이용하였다. 만경강 하천부지에 각 층을 대표하는 깊이에서 지하수위를 관측한 결과, 지하수위가 강수량보다는 하천수위변동에 민감하게 반응하고 있었다. 연구지역의 하천수위변동은 만경강 제수문의 조절과 조석의 영향을 받아 주기적인 수위변동이 우세하기 때문에 강수량과의 상관성은 낮다. 다심도 관정에서 각층별 하천수위에 대한 지하수위 반응은 시간지연 없이 서로 같이 변동하는 것으로 나타났으며, 반응시간은 하천과 가까운 관정에서 30-60분 이내로 빠르며 하천에서 거리가 멀어지면서 반응시간은 대체로 늦게 나타났다. 그러나 하천과 멀리 떨어져 있는 관정이더라도 하천수위에 대하여 빠른 반응을 보이는 관정이 있으며, 이는 하천과 대수층과의 높은 수리적 연결성을 나타낸다. 지하수위의 하천에 대한 반응양상이 다르게 나타나는 것은 대수층의 수리적 불균질성에 의한 것으로 사료된다. 연구지역의 하천은 대체로 지하수위가 하천수위보다 높게 관측되고 있기 때문에 지하수가 하천으로 유출되는 이득하천의 성격을 가지고 있다고 판단되나, 하천의 급격한 수위상승에 따라 역으로 하천의 물이 지하수로 공급되는 손실하천의 성격도 보여주었다. 하천수위와 대수층이 연결된 시스템에서 시계열분석으로서의 자기 및 교차상관분석은 수리적 상호관계를 파악하기 위한 유용한 도구로 활용될 수 있다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권3호
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• pp.23-32
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• 2013

Korean groundwater quality standards were established in 1994, and revised in 2003 and 2010. The substances for which standards have been developed are classified into two groups, general pollutants, 4, and specific pollutants, 15. The standards have been applied to household water use, agriculture, aquaculture, and industrial use. However, there is no systematic methodology for either selecting candidate substances or establishing groundwater standards. We investigated various derivation methodologies for groundwater standards used by the European Commission and 27 member states and compared their methods for determining threshold values. The European Commission presented to their member states groundwater standards for two substances and a list of required substances for derivation of threshold values along with the member states. Interestingly, they first considered national background levels and then considered other criteria for water protection, such as drinking water standards, environmental quality standards, and irrigation standards. We suggest that Korean background levels in groundwater should be included in the methodology for establishing groundwater quality standards. These results may be useful in developing a systematic methodology for establishing Korean groundwater quality standards.

• 한국환경과학회지
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• 제23권4호
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• pp.637-647
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• 2014

Quantitative assessment of groundwater level change under extreme event is important since groundwater system is directly affected by drought. Substantially, groundwater level fluctuation reveals to be delayed from several hours to few months after raining according to the aquifer characteristics. Groundwater system in Jeju Island would be also affected by drought and almost all regions were suffered from a severe drought during summer season (July to September) in 2013. To estimate the effect of precipitation to groundwater system, monthly mean groundwater levels in 2013 compared to those in the past from 48 monitoring wells belong to be largely affected by rainfall(Dr) over Jeju Island were analyzed. Mean groundwater levels during summer season recorded 100 mm lowered of precipitation compared to the past 30 years became decreased to range from 2.63 m to 5.42 m in southern region compared to the past and continued to December. These decreasing trends are also found in western(from -1.21 m to -4.06 m), eastern(-0.91 m to -3.24 m), and northern region(from 0.58 m to -4.02 m), respectively. Moreover, the response of groundwater level from drought turned out to be -3.80 m in August after delaying about one month. Therefore, severe drought in 2013 played an important role on groundwater system in Jeju Island and the effect of drought for groundwater level fluctuation was higher in southern region than other ones according to the regional difference of precipitation decrease.

• 한국지하수토양환경학회지:지하수토양환경
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• 제27권6호
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• pp.22-36
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• 2022

Water resources in Jeju Island are dependent virtually entirely on groundwater. For groundwater resources, drought damage can cause environmental and economic losses because it progresses slowly and occurs for a long time in a large area. Therefore, this study quantitatively evaluated groundwater level fluctuations using principal component and cluster analyses for 42 monitoring wells in Jeju Island, and further identified the types of groundwater fluctuations caused by drought. As a result of principal component analysis for the monthly average groundwater level during 2005-2019 and the daily average groundwater level during the dry season, it was found that the first three principal components account for most of the variance 74.5-93.5% of the total data. In the cluster analysis using these three principal components, most of wells belong to Cluster 1, and seasonal characteristics have a significant impact on groundwater fluctuations. However, wells belonging to Cluster 2 with high factor loadings of components 2 and 3 affected by groundwater pumping, tide levels, and nearby surface water are mainly distributed on the west coast. Based on these results, it is expected that groundwater in the western area will be more vulnerable to saltwater intrusion and groundwater depletion caused by drought.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 총회 및 춘계학술발표회
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• pp.213-216
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• 2002

To investigate the conditions of groundwater resources in Jeonju, Wanju, and Goksung areas, a basic groundwater survey was performed. From the survey, various useful informations such as groundwater use, waterlevel distribution, water chemistry were obtained. This study focused on the analysis of the water levels, which were automatically monitored with pressure transducers or manually measured. The monitorings were conducted for both shallow wells completed in alluvial aquifers and deep wells in bedrock aquifers. This study presents results of the investigation.

• 한국지구과학회지
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• 제42권5호
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• pp.556-570
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• 2021

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.

• 지질공학
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• 제28권4호
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• pp.583-592
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• 2018

최근들어 방사형 집수정 방식의 대용량 강변여과수 개발에 따른 배후지의 지하수위 강하에 대한 우려가 존재하고 있다. 본 연구에서는 안성천의 방사형 집수정을 대상으로 Modflow를 활용하여 수평정의 취수량에 따른 배후지의 수위 강하를 예측하였으며, 이 데이터를 기반으로 배후지 수위 강하가 최소가 되는 수평정별 취수량을 결정하는 다층퍼셉트론 기반의 인공신경망 모델을 개발하였다. 하천 방향으로 굴착된 수평정 HW-6의 취수량을 높이는 것이 OW-7 및 OB-11 관측정의 지하수위를 높게 유지하는데 필요한 것으로 평가되었다. 또한, 모델 입력 자료의 수 및 훈련과 검증 자료의 분류는 인공신경망 모델 결과에 영향을 미치므로 유의하여야 한다. 향후 현장의 실제 운영 자료와 수치모델의 비교를 통하여 인공신경망 모델을 보완한다면 배후지의 지하수 관리에 기여할 것으로 본다.