• Journal of Korean Society of Disaster and Security
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• v.13 no.4
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• pp.65-74
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• 2020

Continuous and accurate instrument of river water usage is needed for sustainable river water management. Although the instrument methods applicable to each point of use of river water are different, more precise direct instrument methods are required at the point of major open channel. Users of river water should select appropriate direct instrument methods to measure usage, but there is a lack of standards and verification research. In this study, the H-Q rating curve method, ultrasonic method, and microwave method were applied directly to the test basin in the upper basin of Mangyeong river, and the accuracy of measurement data was evaluated by comparing absolute error between discharge data calculated by instrument method. When comparing the calculated discharge of point units, the ultrasonic method showed the best results of the actual measurement. Through continuous instrument, the sum of the daily and monthly units was compared, and the ultrasonic and microwave methods were shown to be highly accurate. Based on the results of this study, it is hoped that the appropriate direct measurement method can be selected according to the importance of the river water use facility, considering that the ultrasonic method and the microwave method are relatively costly compared to the water level-flow relationship method.

• Journal of the Korean Geographical Society
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• v.51 no.6
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• pp.779-797
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• 2016

A calibrated hydrological model is a useful tool for quantifying the impacts of the climate variations and land use/land cover changes on sediment load, water quality and runoff. In the rainy season each year, the Xe Bang Fai river basin is provisionally flooded because of typhoons, the frequency and intensity of which are sensitive to ongoing climate change. Severe heavy rainfall has continuously occurred in this basin area, often causing severe floods at downstream of the Xe Bang Fai river basin. The main purpose of this study is to investigate the climate change impact on river discharge using a Soil and Water Assessment Tool (SWAT) model based on future climate change scenarios. In this study, the simulation of hydrological river discharge is used by SWAT model, covering a total area of $10,064km^2$ in the central part of country. The hydrological model (baseline) is calibrated and validated for two periods: 2001-2005 and 2006-2010, respectively. The monthly simulation outcomes during the calibration and validation model are good results with $R^2$ > 0.9 and ENS > 0.9. Because of ongoing climate change, three climate models (IPSL CM5A-MR 2030, GISS E2-R-CC 2030 and GFDL CM3 2030) indicate that the rainfall in this area is likely to increase up to 10% during the summer monsoon season in the near future, year 2030. As a result of these precipitation increases, the SWAT model predicts rainy season (Jul-Aug-Sep) river discharge at the Xebangfai@bridge station will be about $800m^3/s$ larger than the present. This calibrated model is expected to contribute for preventing flood disaster risk and sustainable development of Laos

• Journal of Korean Society of Environmental Engineers
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• v.22 no.2
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• pp.355-362
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• 2000

The objective of this paper is to estimate the pollutant load based on event mear concentrations(EMC) in industrial complex. Eight sub-basins in the Chongju industrial complex were selected for sampling and study with different characteristics during the period from June 1997 to August 1998. During the storm events, measured EMC ranges of $BOD_5$, COD, SS, TKN, TP, HEM, $NO_3-N$, $PO_4-P$, Cr, Pb, Cu and Fe in the industrial complex watersheds were 11~176mg/L, 40~502mg/L, 23~633mg/L, 104~20.9mg/L, 0.22~7.51mg/L, 12.7~548.7mg/L, 0.06~2.66mg/L, 0.12~3.39mg/L, 0.01~0.50mg/L. 0.02~0.42mg/L, 0.01~0.15mg/L and 1.29~11.51mg/L respectively. And the calculated annual average pollutant unit loadings of $BOD_5$ COD, SS, TKN, $NO_3-N$, $PO_4-P$, TP, HEM, Cr, Pb, Cu and Fe were 374.4kg/ha/yr 924.1kg/ha/yr, 983.6kg/ha/yr, 48.8kg/ha/yr, 8.1kg/ha/yr, 9.7kg/ha/yr, 17.8kg/ha/yr 943.0kg/ha/yr, 0.7kg/ha/yr, 0.9kg/ha/yr, 0.3kg/ha/yr and 28.9kg/ha/yr, respectively.

• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.4 s.27
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• pp.301-306
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• 2006

In order to estimate the characteristics of water movements around artificial upwelling structure, current measurements were carried out along lines E-W and S-N on May 4th(neap tide} and May 30th(spring tide), 2006. In the study area, southeastward flow was dominant during the field observations, and the pattern of water movement in the upper layer above 30m depth was different from that in the lower layer below 30m depth Vertical flow(w-component} around the artificial structure area and western area was shown to be upward flow, but downward flow occurred in the southern, northern and eastern parts at the neap tide. At the spring tide, the ebb current along E-W line showed upwelling flow in the eastern part and western area and showed upwelling flow near the artificial structure area and downwelling flow far away that one. At the spring tide, upward flow was dominant along S-N line during the flood current Volume transport by upward flow was higher than that by downward flow. Volume transport by upward flow during ebb of neap tide was greater than during flood current of neap tide, but was reverse at the spring tide.

• Korean Journal of Ecology and Environment
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• v.35 no.1 s.97
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• pp.21-27
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• 2002

The frequent occurrence of excessive phytoplankton populations in the downstream Nakdong River has been an important water quality problem in recent years. The limnological survey of the Nakdong River was conducted from January 1997 to December 1999 on once or twice per month. A typical phenomenon of eutrophication appears with the persistent algal bloom due to high nutrients in the mid-lower part of the river. This study showed that the point at which Chl. a concentration reaches maximum was affected by the water temperature and the flow rate. For example, Chl. a concentration reached maximum after around 380, 240 and 120 hours which were estimated from the time of flow at low (${\le}10^{\circ}C$), mean ($10{\sim}20^{\circ}C$) and high (${\ge}20^{\circ}C$) water temperature conditions, respectively. It was estimated that increase coefficients of phytoplankton (Chl. a) on the water temperature are 0.201, 0.254 and $0.289\;day^{-1}$, on the contrary, decrease coefficients are -0.012, -0.128 and $-0.193\;day^{-1}$ in low, mean and high water temperature. Therefore, to prevent formation of Chl. a maximum concentration in the specific water resource, it is necessary to increase the discharge of dam as well as to decrease.

• Korean Journal of Environment and Ecology
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• v.29 no.6
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• pp.917-922
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• 2015

This study was carried out to investigate solutes concentration change with respect to discharge change in coniferous forest experiment watershed in Gyeonggi-do, Korea. From 2005 to 2008. Precipitation, discharge, solutes has been analyzed from 23 precipitation events. The results showed that low API induced low discharge. $NH_4{^+}$, $K^+$, and $Ca^{2+}$ were indicated by clockwise and $Cl^-$ and $NO_3{^-}$ were represented by counterclockwise hysteresis loop. ${SO_4}^{2-}$, $Na^+$, $Mg^{2+}$ showed no hysteresis loop pattern. $Cl^-$, $Na^+$, $NH_4{^+}$ was relatively constant due to groundwater during precipitation, $NO_3{^-}$ was increased due to soil water compared to early precipitation. $Cl^-$, ${SO_4}^{2-}$, $Na^+$, $Mg^{2+}$, $Ca^{2+}$ was diluted with respect to increased discharge and $NO_3{^-}$ was diluted in early precipitation and then increased in the end. $NO_3{^-}$ and $Ca^{2+}$ eluviated in early precipitation. This characteristics was presumed by the effect of API, discharge and ground water.

• Journal of Korea Water Resources Association
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• v.45 no.12
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• pp.1259-1273
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• 2012

In this study, a watershed-based surface water and groundwater integrated model, SWAT-MODFLOW was used to quantify the stream flow depletion due to groundwater pumping for the Sinduncheon watershed. Complex water use conditions such as water taken from a stream, sewage disposal release, irrigation from agricultural reservoir, groundwater pumping were considered for simulations. In particular, the model was revised to reflect the effects of reservoir operation and return flow from the used groundwater on streamflow variation. The simulated results showed that the groundwater pumping at current status has induced the decrease of more than 10% in annual average streamflow and 40% in drought flow at the outlet of the Sinduncheon watershed, The simulated results also revealed that the vast water withdrawals at green house areas during winter season have dramatically changed streamflow from April to June. The streamflow depletion was mainly attributed to pumping wells located within the distance of 300 m from the stream for Sinduncheon watershed.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.125-125
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• 2022

저수지 운영자료는 다목적 댐 경우와 마찬가지로, 유입량, 저수량, 방류량 자료로 구성된다. 여기에 강우량을 포함하여, 실시간으로 관리돼야 한다. 그러나 우리나라 저수지는 저수율 자료만 관리하고 있다. 유입량, 방류량이 없는 것이 아니고 관리를 하지 않는다. 강우량은 전혀 없다. 큰 문제인데, 아직도 그 심각성을 모르고, 대충하면 되는 줄 알고 있다. 가장 기초가 되는 일을 무시하고 물관리를 하고 있는 상황이고, 누구도 그 신뢰성을 믿지 않고 있다. 여기서는 이를 해결하는 방안으로 준 실시간 물수지 모형을 구축하여, 10분 단위, 30분 단위, 1시간 단위로 저수위, 저수량, 유입량, 방류량, 강우량을 연속하여 생산하고 검증하는 체제를 제시한다. 준 실시간의 뜻은 계산에 의하지 않고 유입량을 모의에 의해 적용하고 검증하는 과정이 필요하여, 실시간 보다 하루 이틀 늦게 자료를 생산한다는 의미다. 대상 저수지는 유역 내 강우량 수집이 가능한 유역면적 218.80km², 유효저수량 3,494만m³, 수혜면적 5,117 ha인 탑정지를 선정했다. 탑정지 방류량은 탑정1(폭 7.5m×높이 1.5m), 탑정2(4m×1.6m), 양수장(3m×1.6m) 수로로 관개용수 공급량과, 9연의 수문(9m×7.5m)으로 홍수기 방류량으로 구성된다. 분석기간은 1월1일부터 1시간 단위로 연속하여 기간은 자유롭게 설정하여 검정하는 체제를 갖추고 검증된 결과를 제시토록 했다. 2021년 9월의 1시간 단위의 탑정지 저수지 물수지 모의 결과를 요약하면 다음과 같다. 첫째, 탑정지 유역의 환경부 관리 장선, 양촌, 연산 관측소의 면적우량은 최대 15.3mm, 총 160.4mm(3,510만m³)였고, ONE 모형에 의해 연속유량을 모의한 결과, 유입량은 최대 35.6m³/s, 총 1,464만m³로 유출률 41.7%였다. 둘째, 탑정1, 탑정2, 양수장 수로의 수위자료에 수위-유량 관계식을 적용해 수로유량을 산정한 결과 합하여 최대 16.8m³/s였고, 총 548만m³였으며, 수문 방류량은 최대 20.0m³/s였고, 총 108만m³였다. 셋째, 저수지 수위는 관측수위는 EL.28.21~29.38m, 평균 EL.28.87m, 모의수위는 EL.28.08~29.62m, 평균 EL.28.80m로 나타났고, R²는 0.910로 만족한 결과를 얻었다. 정리하면 저수지 운영자료가 없는데도, 10분, 1시간 단위로 연속으로 유입량, 저수량을 모의하여 관측저수량과 비교한 결과가 괄목할 신뢰도를 나타냈다. 이를 바탕으로 저수량, 유입량, 방류량, 강우량 등 준 실시간 저수지 운영자료 생산체제를 마련한 것으로 결론을 내렸다.

• Korean Journal of Environmental Agriculture
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• v.19 no.4
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• pp.339-344
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• 2000

Utilization of animal excreta in aquaculture can have potentials of high fish production and low maintenance costs for fish farming and it can reduce water pollution caused by animal waste disposal. Integration of wastewater treatment pond system with aquaculture has been utilized in many countries. Ecologically balanced pond ecosystem is formed through the stabilization of wastes, the growth of aquatic plants, and the cultivation of fish. The most appropriate fish for rearing in these ponds are those which can feed directly on phytoplankton, especially algae. Carp were introduced into a tertiary pond - water depth of 2.2 m, water surface area of $130\;m^2$, volume of $148\;m^3$ - of a pond system treating milk cow excreta. The carp production was $125g{\cdot}m^{-2}year^{-1}$ which falls into upper range of $18\;-\;137g{\cdot}m^{-2}year^{-1}$ of treated sewage-fed carp farming of other countries. Average $BOD_5$ and T-N of the pond was 19.8 and $21.0\;mg{\cdot}L^{-1}$ respectively, and the ecological environment of it was suitable for growth of carp. Several carp of 100g were introduced in August into a secondary pond of the treatment system, whose average $BOD_5$ and T-N was 27.9 and $30.8\;mg{\cdot}L^{-1}$ respectively. They were died within one week, which may be attributed to the depletion of dissolved oxygen at dawn. Effluents from primary treatment can be used in fish pond with dilution and those from secondary treatment can be directly funnelled into it. Waste stabilization pond treating animal excreta can be utilized for fish rearing when its water quality maintains secondary treatment level.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.283-287
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• 2011

농업비점오염원의 오염원 관리를 위해서는 오염물질의 발생과 운반에 직접적으로 영향을 미치는 농업수문학 기술에 바탕을 두고 우리나라의 집약농업의 특성을 정확히 반영할 수 있는 최적관리방법의 개발과 비점오염저감효과를 검증할 수 있는 현장실험이 수반되어야 한다. 따라서 본 연구에서는 지표피복재를 이용하여 밭의 토양침투를 증가시고 유속 및 유출량 감소를 통해 토양유실과 비점오염원을 저감하고자 하였다. 실험방법은 실제 영농과 동일하게 무를 재배한 뒤 볏짚거적을 이용하여 밭의 토양 표면을 피복하여 유량과 수질농도를 측정하였다. 연구기간 동안 총 3차례(2010년 9월 9~12일, 9월 21일, 10월 2~3일)의 강우가 발생하였고, 이때 발생한 강우량은 각 359.2 mm, 49 mm, 28.8 mm이였다. 각 시험포에서 볏짚거적으로 인해 저감된 유출량의 저감효율은 볏짚거적을 피복하지 않은 나지상태의 밭 보다 약 33∼75%의 저감효과가 있는 것으로 나타났다. 75%의 유출률 저감 효과가 가장 크게 나타난 강우사상은 30 mm 이하의 강우가 발생한 10월 2~3일의 강우사상에서 나타났다. 강우량과 강우강도는 28.8 mm와 1.92 mm/hr으로 나타났으며, 이때 발생한 유출량은 나지에서 $0.36\;m^3$, 볏짚거적을 피복한 시험포에서는 $0.08\;m^3$이 발생하였다. 나지상태와 볏짚거적을 피복한 시험포의 오염부하의 값을 비교한 결과 볏짚거적을 피복한 시험포에서 $BOD_5$ 항목은 64.3%, SS 80.8%, $COD_{Mn}$ 66.7%, DOC 80.2%, T-N 56.6% 그리고 T-P 56.1%의 오염부하 저감효과가 나타났다. 본 연구의 결과와 같이 지표를 볏짚거적으로 피복할 경우 시험포에서 유출시작 시간 지연효과와 강우에 의한 첨두유출량 및 유출량 감소 효과가 나타나는 것으로 나타났으며, 연구결과는 농업 비점오염원의 최적관리를 위한 과학적 근거자료 제공 및 기초자료로 활용할 수 있을 것으로 판단된다.