• Journal of Soil and Groundwater Environment
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• v.21 no.1
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• pp.61-71
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• 2016

Visual MODFLOW was used for quantifying stream-aquifer interactions caused by seasonal groundwater pumping. A hypothetical conceptual model was assumed to represent a stream-aquifer system commonly found in Korea. The model considered a two-layered aquifer with the upper alluvium and the lower bedrock and a stream showing seasonal water level fluctuations. Our results show that seasonal variation of the stream depletion rate (SDR) as well as the groundwater depletion depends on the stream depletion factor (SDF), which is determined by aquifer parameters and the distance from the pumping well to the stream. For pumping wells with large SDF, groundwater was considerably depleted for a long time of years and the streamflow decreased throughout the whole year. The impacts of return flow were also examined by recalculating SDR with an assumed ratio of immediate irrigation return flow to the stream. Return flow over 50% of pumping rate could increase the streamflow during the period of seasonal pumping. The model also showed that SDR was affected by both the conductance between the aquifer and the stream bed and screen depths of the pumping well. Our results can be used for preliminary assessment of water budget analysis aimed to plan an integrated management of water resources in riparian areas threatened by heavy pumping.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.6
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• pp.167-175
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• 2013

The objective of this study was to investigate the nutrient load balance in the reservoir irrigated paddy block during growing seasons. Idong reservoir irrigation paddy block of 10.3 ha in size was selected to collect hydrologic and water quality data. Irrigation, canal flows, and paddy field drainage were measured using a water level gauge, while water samples were collected and analysed for water quality. The water balance analysis showed that 81 % and 75 % of total outflow were through paddy and irrigation canal drainage during 2011 and 2012, respectively. The water quality of paddy field drainage varied greatly depending on rice cultivation stage ranging from 0.05 to 24.55 mg/L and from 0.01 to 0.76 mg/L for T-N and T-P, correspondently. Paddy field drainage loads during May through June account for 64 % and 76 % in 2012 and 2013, while 82 % and 81 % for T-P in 2011 and 2012, respectively. The Pearson correlation analysis showed that rainfall was significantly correlated with nutrient loads during July through August due to runoff, and irrigation was related with nutrient loads of drainage during some period of July through September due to irrigation return flow. This study results showed characteristics of inflow and outflow nutrient loads from plentiful irrigated paddy block.

• Journal of Korea Water Resources Association
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• v.46 no.7
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• pp.719-733
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• 2013

In this study, a watershed-based surface-water and groundwater integrated model, SWAT-MODFLOW was used to evaluate streamflow depletion induced by groundwater withdrawals and irrigation reservoirs for the Juksan-cheon watershed in South Korea. The streamflow responses to groundwater pumping and irrigation reservoirs were simulated under several different scenarios. The scenarios were (1) current pumping well withdrawals with reservoirs; (2) current pumping well withdrawals without reservoirs; (3) no pumping well withdrawals with reservoirs; (4) no pumping well withdrawals without reservoirs (natural condition). The simulated results indicated that the effects of groundwater pumping on streamflow depletion are a little more significant than those of irrigation reservoirs. Particularly, the groundwater withdrawals with irrigation reservoirs at current status (scenario 1) has induced the decrease of more than 20% in drought flow against the natural condition (scenario 4) at the outlet of the watershed. The specific drought flows through the main stream of Juksan-cheon watershed were simulated in order to assess the irrigation effects on downstream flows. It was found out that the specific drought flows are increasing as the distance from the reservoir increases due to the accumulation of the return flows to stream.

• Water for future
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• v.11 no.2
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• pp.43-53
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• 1978

Synopsis: This study has systemized the results of construction and classification with 656 large dams in Korea which were defined in ICOLD provision. Especially, checking up the drainage capability of large capacity outlets and its of spillway, this paper suggests the planning of outflow discharge with large capacity outlets and spillway in future. The results of this study are following as; 1. The classification by purposes in Korea shows that irrigation dams are 94% in rate(607 dams), jydropower and multipurpose dams are 2% (14 dams), municipal and industrial water supply dams are 4% (26 dams). 2. In design of proposed outflow discharge, spillways of irrigation dams were selected outflow discharge on 100 years return period, those of municipal and industrial water supply dmas 200 years and those of hydropower and multipurpose dams 500 years or 1000 years. 3. Emergency spillway should be considered in the fields of disaster prevention engineering and the rank of return periods for the emergency proposed out flow discharge was suggested. 4. Some of problems are suggested for this subject in future.

• Journal of agriculture & life science
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• v.45 no.6
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• pp.237-249
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• 2011

The purpose of this study was to monitor the streamflow of rural streams for investigating the status of stream depletion located downstream of irrigation reservoir. Bonghyun and Hi reservoirs area, located in Gyeongnam, Gosung-gun, Hi-myeon, were selected for study watersheds and streams. Streamflow monitoring were conducted 6 times during the paddy growing season of 2010 from May to October. Streamflow was measured for 18 stations downstream from two reservoirs with the interval of 300m to 500m, The amount of streamflow were highly dependent on the antecedent precipitation and irrigation amount. In most observation stations, streamflow was depleted when precipitation and irrigation were not provided. Pumping from stream for irrigation and water supply for factory and irrigation return flow were also factors on streamflow. Continuous monitoring for rural streams located in downstream of reservoirs are required to quantify the status of streamflow depletion and determine the amount of environmental flows.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.373-376
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• 2002

It is reported that Korea is a county of water shortage. The government make plans to construct dam to cope with this problem. But, it become difficult to construct dam, because of public opinion of residents and objection of environmentalist. In the sense, the government set up new policy of demand-management which means water saving. It is known that the efficiency of agricultural water is so poor that the first target to save water is focussed on agricultural water. In the study, the function of agricultural water was evaluated and it is found that it is not a waste, but a good ability on eco-system by return flow.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.630-634
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• 2004

현재까지 대부분의 유출 모형들은 우리나라 농업지역에 내한 적용에 있어 많은 수정이 요구되고, 그에 따른 모의 결과 또한 불확실성을 내포하고 있으며, 이의 원인중 상당수는 농업지역에서 발생하는 관개와 회귀에 따른 것이라 찰 수 있다. 특히 농업지역에서의 유출 및 물사용에 대한 정확한 계측이 제대로 이루어지고 있지 못하기 때문에, 그에 따른 정확한 수자원 평가가 어려운 현실이다. 이에 본 논문에서는 본 연구진에서 기 개발한 순물소모량 산정방법과 회귀 관계식으로 보청천 유역의 회귀특성을 규명하고자 하였으며, 본 연구에서 사용한 모형은 SWAT모형의 농업용수 관개 기능을 보완한 SWAT-AGRIMANAGEMENT모형을 개발 이용하였다. 유역규모에서의 농업용수 사용에 따른 하천유량의 변화 및 유역내 회귀관계를 파악할 수 있었으며, 기존에 주로 관개지구 단위에서의 회귀수량 조사 결과 및 가정에 의하여 사용되던 농업용수 회귀율에 대한 보다 의미있는 기준을 제시할 수 있을 것으로 기대된다.

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.3
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• pp.71-80
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• 2016

The component-based modeling framework for agricultural water-resources management (COMFARM) is a user-friendly, highly interoperable, lightweight modeling framework that supports the development of watershed-specific domain components. The objective of this study was to evaluate the suitability of the COMFARM for the design and creation of a component-based modeling system of agricultural reservoir watersheds. A case study that focused on a particular modeling system was conducted on a watershed that includes the Daehwa and Dangwol serial irrigation reservoirs. The hydrologic modeling system for the study area was constructed with linkable components, including the modified Tank, an agricultural water supply and drainage model, and a reservoir water balance model. The model parameters were each calibrated for two years, based on observed reservoir water levels. The simulated results were in good agreement with the observed data. In addition, the applicability of the COMFARM was evaluated for regions where reservoir outflows, including not only spillway release but also return flow by irrigation water supply, substantially affect the downstream river discharge. The COMFARM could help to develop effective water-management measures by allowing the construction of a modeling system and evaluation of multiple operational scenarios customized for a specific watershed.

• Journal of Korea Water Resources Association
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• v.52 no.7
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• pp.483-492
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• 2019

An analytical model was developed to estimate the stream depletion due to cyclic groundwater pumping by extending the Hunt's analytical solution which was derived from considering the hydraulic characteristics of the aquifer and the streambed. The model was applied to analyze the long-term effects of groundwater pumping on stream depletion during irrigation season. For the case of a total of 1,500 conditions according to various aquifer and streambed hydraulic characteristics and stream-well distance, the stream depletion due to cyclic groundwater pumping for 10 years was calculated and the results were graphically represented. Especially, the maximum and average stream depletion rates were calculated and compared with the results for continuous groundwater pumping. Furthermore, considering both stream depletion and return flow rates, the limit hydraulic condition that minimizes the influence of groundwater pumping for irrigation water supply on stream depletion was suggested.

• Archives of Plastic Surgery
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• v.40 no.3
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• pp.251-255
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• 2013

We present a case of a 57-year-old male patient who presented with squamous cell carcinoma on his mouth floor with cervical and mandibular metastases. Wide glossectomy with intergonial mandibular ostectomy, and sequential reconstruction using fibular osteomyocutaneous free flap were planned. When the anastomosis between the peroneal artery of the fibular free flap and the right lingual artery was performed, no venous flow was observed at the vena comitans. Then re-anastomosis followed by topical application of papaverine and lidocaine was attempted. However, the blood supply was not recovered. Warm saline irrigation over 30 minutes was also useless. Microvascular thromboses of donor vessels were clinically suspected, so a solution of 100,000 units of urokinase was infused once through a 26-gauge angiocatheter inserted into the recipient artery just at the arterial anastomotic site, until the solution gushed out through the flap vena comitans. Immediately after the application of urokinase, arterial flow and venous return were restored. There were no complications during the follow-up period of 11 months. We believe that vibrating injuries from the reciprocating saw during osteotomies and flap insetting might be the cause of microvascular thromboses. The use of urokinase may provide a viable option for the treatment of suspicious intraoperative arterial thrombosis.