Efficient groundwater management requires accurate information about the water volume used. The pumped volume of groundwater can be indirectly estimated using empirical formulae based on electric power consumption. The purpose of this study is to test the accuracy of this indirect method. The Haean basin in Gangwon is located in a rural area, where majority of the groundwater extracted is used for irrigation. The pumped volume of groundwater indirectly estimated from electricity usage using these empirical formulae was compared with the actual pumped volume determined by conducting experiments on April 29 and May 19, 2017. The field survey collected data on electricity usage, pumped volume, and groundwater levels. Based on this measured data, correlations were calculated between electricity usage and pumping volume, as well as groundwater level and pumping rate. The results show that electricity usage and pumped volume measured for both wells (YHE1 and YHE2) are highly correlated (r=0.99, p<0.001). However, for YHE1, notably, the correlation between the groundwater level and pumping rate was not significant, and only some correlations were identified for these variables for the YHE2 test well. The average error with respect to the estimation of the actual pumped volume from the existing formula (1) and formulae (2) and (3) are +399% and -88%, respectively. To reduce these errors, these formulae need to consider other factors affecting the pumped volume.
Coastal aquifers are complex systems governed by fresh-saline water interactions and ocean tidal effects. The vertical electrical conductivity (EC) and temperature (T) are general indicators for detecting the fresh-saline water interface (FSI) and sea water intrusion in groundwater wells located in coastal aquifers. In this method brief, we developed a cost-effective Arduino-based automatic-vertical profile monitoring system (A-VPMS) to continuously record vertical EC and T in groundwater wells, with the aim of testing its effectiveness in spatiotemporal monitoring of the FSI in a coastal aquifer located in eastern Korea. By analyzing the high-density EC and T data obtained by the A-VPMS, we evaluated the characteristics of the FSI, such as depth and spatial distribution. Our established EC and T data collection method using the A-VPMS proved to be efficient and reliable, providing an excellent tool for fine-scale temporal and spatial understanding of sea water intrusion. The results of this study demonstrate the potential of the A-VPMS for continuous monitoring of the FSI in coastal aquifers, which is crucial for sustainable management of groundwater resources.
Community drinking water (CDW), mostly naturally flowing groundwater, plays important roles in supplying drinking water for urban and rural residents in Korea. Over 1,600 CDW facilities are distributed throughout the country, many of them situated in the outskirts of metropolitan cities. A large proportion of Korean people have become dependent on CDW for drinking due to a distrust of piped water's quality and a strong belief in the special medicinal effects of some CDWs. However, administrative and official management and the control of CDW facilities have been inadequate when compared with the strict examination and control of commercial bottled water, which is physically treated groundwater from deep bedrock aquifers. In this study, even though signs of anthropogenic contamination were not generally found, the tested chemical compositions of selected CDWs featured high enrichment of some constituents including Ca, Mg, Na, and HCO3 with natural origins such as water-rock interactions. Careless consumption of particular CDWs, which has no scientific basis, will not guarantee health improvement. Consequently, more intensive management of CDW facilities and a long-term interdisciplinary examination of the health effects of CDWs are needed to effectively protect people's health.
이 연구에서는 우리나라의 지하수와 지표수의 장기간(1996~2015) 변동을 비교·분석 하였다. 이를 위해 우리나라의 지하수위, 댐저수량 및 강수량 자료와 미국에서 제공하는 Gravity Recovery and Climate Experiment(GRACE)와 Global Land Assimilation System (GLDAS) 자료를 수집하였다. 연구결과 1996~2015년 동안 우리나라의 연강수량은 948~1,857 mm/yr의 변동범위를 보였고 약 4.4년 주기로 가뭄이 발생하였다. 지하수위 이상편차(anomaly)와 댐 수위 이상편차의 중앙값은 각각 -0.4~+0.4, -4.0~+4.0 m 변동을 보였다. 강수량과 지하수위 및 댐 수위는 특히 1996, 2001, 2008, 2014, 2015년에 감소하였다. 또한 2014, 2015년에는 GRACE의 총물저장량(Total Water Storage Anomaly, TWSA)과 GLDAS의 지표총수분량(Total Water Content Anomaly, TWCA)도 감소하여 우리나라의 극심한 수문학적 가뭄을 지시하였다.
Abstract To enhance the understanding of solute dynamics within the stream‐to‐riparian continuum during flood event‐driven water fluctuation (i.e., flood wave), a variable saturated groundwater flow and solute transport model were developed and calibrated against in situ measurements of the Inbuk stream, Korea, where seasonal flooding prevails. The solute dynamics were further investigated for flood waves (varying by amplitude [ A ], duration [ T ], roundness [ r ], and skewness [ t p ]) that were parameterised by real‐time stream stage fluctuations. We found that the solute transferred faster and farther in the riparian zone, especially within the phreatic zone, above which in the variable saturated zone the concentration required a significantly longer time, particularly at higher altitudes, to return to the initial state. By comparison, solute transferred shallowly in the streambed where the solute plume exhibited an exponential growth trend from the centre to the bank. The dynamic changes of solute flux and mass along the stream–aquifer interface and stream concentration were linked to the shape of flood wave. As the flood wave became higher ( A ↗), wider ( T ↗), rounder ( r ↘), and less skewed ( t p ↗), the maximum solute storage in aquifer increased. Maximum stream concentration ( C strˍmax ) not only presented a positive linear relationship with A or t p but also showed a negative logarithmic trend with increasing T or r. The sensitivity of C str_max to A was approximately two times that of t p , and between these values, the r was slightly more sensitive than T. C strˍmax linearly increased as hydraulic conductivity increased and logarithmically increased as longitudinal dispersivity increased. The former relationship was more sensitive than the latter.
본 연구에서는 남극 바톤반도 해안에서 내륙으로 1.5 ㎞ 이격한 경사각(18, 15, 8°)이 다른 3개 관측지점에서 토양수분 및 지온을 측정하였다. 이들의 시계열적 특성을 파악하기 위하여 자기상관분석, 스펙트럼분석 및 교차상관분석을 하였다. 또한 활동층의 열적 특성을 해석하기 위해 열확산계수를 산정하고 두께를 추산하였다. 토양수분 및 지온 센서는 5, 10, 15, 20 ㎝ 깊이에 설치하였고 2019년 12월 19일부터 2020년 1월 4일까지 17일간 5분 간격으로 측정하였다. 토양수분 함량이 모든 지점의 20 ㎝ 깊이에서 가장 많았다. 0.5 ㎜/day 이하의 강우는 토양수분 함량에 영향을 미치지 못했다. 토양온도는 최대 13.2℃, 최소 -0.6℃였으며 중앙값은 깊어질수록 낮았고 12월 20일 1~5시를 제외하고는 24시간 동안 0℃ 이상이었다. 자기상관분석 결과 경사각이 완만할수록 토양수분에 대한 지연시간이, 얕을수록 토양온도에 대한 지연시간이 짧았다. 토양수분의 주기는 2.5-4.7일, 토양온도의 주기는 1.0-1.1일이었다. 기온(입력)과 토양온도(출력)에 대한 교차상관분석 결과, 입력값을 태양복사로 했을 때보다 지연시간이 더 짧고 상관계수가 더 컸다. 열확산계수는 0.01-121.94 ㎟/sec의 범위(중앙값=0.34-0.59 ㎟/sec)였다. 이 중앙값은 동일 방법을 이용한 기존 연구의 값(0.4-3.3 ㎟/sec)의 최솟값에 가까웠다. 활동층의 두께는 23.6-38.6 ㎝이며 이는 기존에 연구된 바톤반도 해안 근처(0.2 ㎞ 이내)의 활동층 두께(41-77 ㎝)보다 얇다. 이렇게 열확산계수가 작고 활동층 두께가 얇은 이유는 이번 연구지역이 기존 연구보다 해안으로부터 멀리 떨어져 있기 때문으로 사료된다.
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