• 한국농공학회논문집
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• 제64권2호
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• pp.27-35
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• 2022

Based on the current status of groundwater usage in the dry season through field surveys, this study tried to suggest countermeasures to reduce groundwater usage and to improve the water quality of baseflow from agricultural fields. For this purposes, basins with water curtain cultivation preceded were targeted where decreases of groundwater due to continuous use of groundwater in spring and winter annually observed. From monitoring groudwater usage of the study watershed, 130,058, 130,105 m³/day of water was pumped in during the water curtain cultivation period (October-February) in the Shindun, Seokwon watershed respectively. And the pilot application of the smart automated sensor-based water curtain cultivation system (smart WC system) developed in this study to reduce groundwater consumption has been conducted. As a result, the efficiency of the smart WC system when threshold temperature is set as 6.3 ℃ was 21.1% compared to conventional cultivation and efficiency increased as threshold temperature gets lower. Lastly, in this study, culvert drainage and Bio-filters were installed and rainfall monitoring was performed 15 times in order to analyze the baseflow securement and pollutant loads behavior. As a result, the test-bed with culvert drainage and Bio-filter installed together generated 61.4% more baseflow (4.974 m³) than the test-bed with only culvert drainage was installed (3.056 m³). However, the total pollutant load of all water quality contents (BOD, COD, T-N, TOC) except for the SS and T-P was found to be greater in the culvert drain and Bio-filter installed than in the culvert drain test-bed.

• 한국농공학회논문집
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• 제52권3호
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• pp.65-71
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• 2010

This study was conducted to investigate the dynamics of nutrients such as total nitrogen (TN), nitrate nitrogen ($NO_3$-N) total phosphorous (TP), and phosphate phosphorous ($PO_4$-P) in outflow from a cabbage farmland in a mixed land-use watershed. The TN concentrations in groundwater showed twice peaks in late July 2006 and late March 2007 (3.8, 4.7 mg/L, respectively), when it rained shortly after fertilizer application, indicating that nitrogen leaching is greatly influenced by fertilization and rainfall. The mean concentrations of TN and $NO_3$-N in surface water were not significantly higher than those in groundwater, while the mean concentrations of TP and $PO_4$-P in surface water were significantly (p < 0.05) were higher than those in groundwater. The TN concentrations in groundwater were generally higher than those in surface water during fertilization and early growing season due to the effect of fertilization, but vice versa in the other periods. In contrast, the TP concentrations in groundwater were always lower than those in surface water due to the sorption of particulate phosphorous by soil. The ratio of TN load in baseflow to that in total TN load (39 %) was much greater than the TP ratio (7 %), suggesting that baseflow contribute to nitrogen export. Therefore, proper fertilization management should be taken to reduce nitrogen load through baseflow.

• 한국농공학회지
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• 제30권2호
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• pp.31-43
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• 1988

The Purpose of this study is to develop the rainfall-delayed response model (RDR Model) which influences the baseflow proportion of rivers as a result of the antecedent precipitation of the previous several months. The assesment of accurate baseflows in the rivers is one of the most important elements for the planning of seasonal water supply for agriculture, water resources development, hydrological studies for the availability of water and design criteria for various irrigation facilities. The Palukan river gauging site which is located in the Pulukan catchment on Bali Island, Indonesia was selected to develop this model. The basic data which has been used comprises the available historic flow records at 19 hydrologic gauging stations and 77 rainfall stations on Bali Island in the study. The methology adopted for the derivation of the RDR model was the water balance equation which is commonly used for any natural catcbment ie.P=R+(catchment losses) -R+(ET+DP+DSM+DGW). The catchment losses consist of evapotranspiration, deep percolation. change in soil moisture, and change in groundwater storage. The catchment areal rainfall has been generated by applying the combination method of Thiessen polygon and Isohyetal lines in the studies. The results obtained from the studies may be summarized as follows ; 1. The rainfall-runoff relationship derived from the water balance equation is as shown below, assuming a relationship of the form Y=AX+B. Finally these two equations for the annual runoff were derived ; ARO$_1$=0.855 ARF-821, ARF>=l,400mm ARO$_2$=0.290ARF- 33, ARF<1,400mm 2. It was found that the correction of observed precipitation by a combination of Thiessen polygons and Isohyetal lines gave good correlation. 3. Analysis of historic flow data and rainfall, shows that surface runoff and base flow are 52 % and 48% (equivalent to 59.4 mm) of the annual runoff, respectively. 4. Among the eight trial RDR models run, Model C provided the correlation with historic flow data. The number of months over which baseflow is distributed and the relative proportions of rainfall contributing in each month, were estimated by performing several trial runs using data for the Pulukan catchment These resulted in a value for N of 4 months with contributing proportions of 0.45, 0.50, 0.03 and 0.02. Thus the baseflow in any month is given by : P$_1$(n) =0.45 P(n) +0.50 P(n-I ) +0.03 P(n-$_2$) +0.02 P(n-$_3$) 5. The RDR model test gave estimated flows within +3.4 % and -1.0 % of the observed flows. 6. In the case of 3 consecutive no rain months, it was verified that 2.8 % of the dependable annual flow will be carried over the following year and 5.8 % of the potential annual baseflow will be transfered to the next year as a result of the rainfall-delayed response. The results of evaluating the pefformance of the RDR Model was generally satisfactory.

• 지질공학
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• 제21권2호
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• pp.107-116
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• 2011

금강유역의 수위관측소에서 관측된 유량자료와 국가 지하수 관측망에서 관리하는 관측소 지하수위 자료를, 두 관측소간의 거리를(10 km 이내) 고려하여, 선정한 후 수집하였다. 관측된 유량자료를 WHAT SYSTEM이라는 Web GIS 기반의 수문분석 프로그램을 이용하여 유량자료에서 기저유출을 분리하였다. 그 후 기저유출 값과 지하수위간의 상관계수를 분석하였다. 2002년부터 2008년까지 조사한 금강유역 내에서 선정된 총 20개 지역 중 지하수위와 기저유출의 상관계수가 0.5 이상인 경우가 발생한 지역은 12개이고 모든 지역의 전체 관측년도에서 상관계수가 0.5~0.6인 경우는 8개, 0.6~0.7인 경우는 5개, 그리고 0.7 이상인 경우는 12개였다. 같은 지역이라도 연도마다 다른 상관관계를 보여주고 있으며 이는 가뭄이나 홍수가 심했던 연도에서 낮은 상관관계를 보여주는 것으로 분석되었다. 결론적으로 상관계수가 높은 지역에서는, 가뭄이나 홍수가 심하지 않는 연도라면, 지하수위 관측만으로도 기저유량을 추정할 수 있다.

• 물과 미래
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• 제29권6호
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• pp.131-139
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• 1996

본 연구의 목적은 분포형 강우-유출 모형에 의한 유출량을 해석하는 것이다. 본 모형은 두개의 부모형으로 구성되어 있다. 하나는 수계망(drainage network) 을 통하여 운동파 모형(kinematic wave model)을 이용하여 분포적으로 추적되는 직접 유출 부모형이며, 다른 하나는 기저유출 부모형으로서 집중형으로 취급되어 유역 출구에서만 계산하도록 하였다. 본 연구에서 개발된 모형에 의하여 청미천 유역에 대한 유출량의 시간적, 공간적인 분포를 고려할 수 있었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.181-188
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• 2002

Water flow rate into the tunnel usually determined by numerical analyses and mathematical formulas using water levels and permeability is obtained only a few limited districts of the whole tunneling site. However, underground is not a homogeneous but complicated mass. Therefore these methods can't reflect structural and geological aspects. In this study, assuming that the mountain stream in droughty season is to be the same as baseflow of its basin, hydrological method is applied to predict the constant water flow rate into the tunnel on construction field. Prediction of constant water inflow rate is performed on each section of tunnel construction field divided into 20 sections.

• 한국수자원학회논문집
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• 제37권5호
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• pp.397-406
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• 2004

어떤 특정 지역의 지하수 개발량을 적적히 파악하기 위해서는 지하수함양량의 산정이 필요하다. 경상북도에 위치한 위천 유역내의 소유역에 대하여 지하수 함양량을 산정하였다. 기저유출분리법과 SCS-CN방법을 이용하여 갈수년과 풍수년이 존재하는 1992년∼1997년간의 년 평균 지하수 함양량을 추정하였다. 기저유출분리법을 이용하여 추정한 결과, 연평균 지하수 함양률이 11.9%∼18.7%로 변화하였으며 계산기간 중의 년 평균 강수에 의한 지하수 함양량은 141.6mm로 지하수함양률은 14.5%이었다. SCS-CN방법을 이용하여 추정한 결과, 연평균 지하수 함양균이 7.9%∼20.9%로 변화하였으며 계산기간 중의 년 평균 강수에 의한 피하수 함양량은 147.4mm 로 지하수 함양률은 15.1%이었다. 두 방법으로 산정한 갈수년과 풍수년이 존재하는 장기간 동안의 년 평균 강수에 의한 지하수 함양량은 지하수 개발에 유용하게 사용할 수 있음을 나타낸다.

• 한국제4기학회지
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• 제17권2호
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• pp.79-84
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• 2003

This study revealed the differences in runoff processes of granite drainage basins in Korea and Mongolia by hydrological measurements in the field. The experimental drainage basins are chosen in Korea (K-basin) and Mongolia (M-basin). Occurrence of intermittent flow in K-basin possibly implies that very quick discharge dominates. The very high runoff coefficient implies that most of effective rainfall quickly discharge by throughflow or pipeflow. The Hortonian overlandflow is thought to almost not occur because of high infiltration capacity originated by coarse grain sized soils of K- basin. Very little baseflow and high runoff coefficient also suggest that rainfall almost does not infiltrate into bedrocks in K-basin. Flood runoff coefficient in M-basin shows less than 1 %. This means that most of rainfall infiltrates or evaporates in M-basin. Runoff characteristics of constant and gradually increasing discharge imply that most of rainfall infiltrates into joint planes of bedrock and flow out from spring very slowly. The hydrograph peaks are sharp and their recession limbs steep. Very short time flood with less than 1-hour lag time in M-basin means that overland flow occurs only associating with rainfall intensity of more than 10 mm/hr. When peak lag time shows less than 1 hour for the size of drainage area of 1 to 10 km2, Hortonian overland flow causes peak discharge (Jones, 1997). The results of electric conductivity suggest that residence time in soils or weathered mantles of M-basin is longer than that of K-basin. Qucik discharge caused by throughflow and pipeflow occurs dominantly in K-basin, whereas baseflow more dominantly occur than quick discharge in M-basin. Quick discharge caused by Hortonian overlandflow only associating with rainfall intensity of more than 10 mm/hr in M-basin.

• 한국물환경학회지
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• 제22권4호
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• pp.648-657
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• 2006

Characteristics of water quantity and quality of the Anyangcheon were analyzed through many field measurements and the distributed hydrologic simulation model, Soil and Water Assessment Tool (SWAT). Event mean concentrations (EMCs) and baseflow mean concentrations were calculated from the data and the daily runoff were simulated by SWAT. The runoff was divided into the direct runoff and the baseflow. Using those values and quantity and quality data of release from the wastewater treatment plant (WWPT), unit loads of BOD, COD, SS, $NO_2-N$, $NO_3-N$, $NH_3-N$, and Dis-P were derived. EMCs of BOD and SS were even higher than the baseflow mean concentrations. The total runoff from October to April (7 months) of 2004 was just 13.5%, since the rainfall usually is concentrated in summer season. Futhermore BOD and SS were loaded during the event by 50.9% and 70.9%, respectively and over three quarters of total COD, $NO_2-N$, $NO_3-N$, $NH_3-N$, and Dis-P were flowed into the Anyangcheon during the remaining period. Therefore, the efficiency of WWPT for COD, $NO_2-N$, $NO_3-N$, $NH_3-N$, and Dis-P should be intensified from Oct. to Apr. and the runoff quality management of BOD and SS should be planned during the summer season.

• 한국수자원학회논문집
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• 제32권4호
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• pp.417-426
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• 1999

횡유입이 없는 경우(sign곡선의 홍수파 유입)와 횡유입이 있는 경우(강우 유입)를 대상으로 선형과 비선형 Muskingum-Cunge법에 의한 단위폭 사면에서의 유출수문곡선의 특성을 비교·고찰하였다. 유출곡선은 선형법에서는 확산효과에 의해서 거의 대칭적으로 확산되나, 비선형법에서는 비선형효과와 확산효과의 상호작용을 의하여 상승부는 급하게 되고, 하강부는 완만하게 된다. 선형법은 유입된 질량을 정확히 보존하나, 비선형법은 질량의 증가나 손실을 초래한다. 비선형법에서 기저유량이 작고 유량변화의 비가 큰 경우, 완경사에서는 파형의 감쇠와 질량의 감소를 가져오나, 급경사에서는 kinematic shock의 생성과 함께 질량의 증가를 가져온다. 같은 특성을 갖는 사면의 경우, 유출곡선의 전파속도와 파형의 변화는 선형법에서는 단위폭당 기준유량에 좌우되나, 비선형법에서는 기저유량 및 유량 변화의 비(= 첨두유량/기저유량)에 좌우된다. 횡유입(강우)이 있는 비선형법의 경우 횡유입이 없는 경우와 마찬가지로, 사면경사가 완만하고 유량변화의 비가 클수록 첨두유량은 작아지고 파형은 확산되나, 질량의 손실은 거의 없다.