• 한국환경과학회지
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• 제5권3호
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• pp.377-385
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• 1996

This study aims at the estimation of a river management flow in urban basin analyzing Sinchun basin to be the tributary of Kumho river basin. The river management flow has to satisfy a low flow as natural flow and an environmental preservation flow estimated by a dilution flow to satisfy a target water quality in drought flow. Therefore for the estimation of a river management flow in Sinchun in this study, first Tank model as a basin runoff model estimates a low flow, a drought flow from a flow duration curve in Sinchun, second QUAL2E model as water quality model simulates water quality in Sinchun and estimates environmental preservation flow to satisfy a target water qua%its, BOD 8 mg/l by a dilution flow derived from Kumho river, Nakdong river and around water. And the river management flow is estimated by addition of a use flow and a loss flow to more flow between a low-flow and an environmental preservation flow.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2015년도 학술발표회
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• pp.243-243
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• 2015

Low-flow simulation and forecasting is one of the emerging issues in hydrology due to the increasing demand of water in dry periods. Even though low-flow simulation and forecasting remains a difficult issue for hydrologists better simulation and earlier prediction of low flows are crucial for efficient water management. The UN has never stated that South Korea is in a water shortage. However, a recent study by MOLIT indicates that Korea will probably lack water by 4.3 billion m3 in 2020 due to several factors, including land cover and climate change impacts. The two main situations that generate low-flow events are an extended dry period (summer low-flow) and an extended period of low temperature (winter low-flow). This situation demands the hydrologists to concentrate more on low-flow hydrology. Korea's annual average precipitation is about 127.6 billion m3 where runoff into rivers and losses accounts 57% and 43% respectively and from 57% runoff discharge to the ocean is accounts 31% and total water use is about 26%. So, saving 6% of the runoff will solve the water shortage problem mentioned above. The main objective of this study is to present the hydrological modelling approach for low-flow simulation and forecasting using a model that have a capacity to represent the real hydrological behavior of the catchment and to address the water management of summer as well as winter low-flow. Two lumped hydrological models (GR4J and CAT) will be applied to calibrate and simulate the streamflow. The models will be applied to Seolmacheon catchment using daily streamflow data at Jeonjeokbigyo station, and the Nash-Sutcliffe efficiencies will be calculated to check the model performance. The expected result will be summarized in a different ways so as to provide decision makers with the probabilistic forecasts and the associated risks of low flows. Finally, the results will be presented and the capacity of the models to provide useful information for efficient water management practice will be discussed.

• 한국수자원학회논문집
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• 제33권1호
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• pp.3-14
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• 2000

본 연구는 최근 하천유지유량에서 중요한 위상을 차지하고 있는 하천생태계에서 어류 서식처를 보전하고 복원하는데 필요한 적정 유량을 산정하는 것이 주된 목적이다. 어류 서식처를 적절히 유지할 수 있는 연과 월갈수량을 산정한다. 이 갈수량을 이용하여 점변 흐름에서 어류 서식처 제공에 필요한 수심과 유속을 모의하고, 또한 수온과 용존산소를 예측한다. 예측된 각 갈수량별 서식 조건과 각 성장단계별 어류 서식처 요구 조건을 도식적으로 비교하다. 이 과정을 남한강의 달철 본류에 위치한 3개 여울 구간에 적용하였다. 달천의 대표어종으로 피라미를 산정하였다. 달천의 피라미(Zacco paltypus)성장단계별 서식처 유지를 위한 적정유량은 수질보다는 수리 조건에 좌우되며, 그 양은 10년 빈도 연갈수량에서 2.33년 빌도 7일 연속갈수량까지의 범위를 갖는 것으로 나타났다.

• 한국환경과학회지
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• 제15권10호
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• pp.967-973
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• 2006

In this study used tank model and specific discharge to calculate low-flow of mountain basin and supply data that need in water resources plan. Low-flow is calculated byspecific discharge and area ratio method as resulted that calculate storage of low-flow by tank model was construed that showd all similar aspect. In judged to help in water resources plan establishment calculating low-flow using model to supplement uncertainty of observed data in that calculate of low-flow ungaged mountain area. It shows by economical and realistic plan until 12 years after development that run parallel and use economic performance analysis result valley flow and groundwater. But wide area water services and Chungju dam since 12 years onward was expose that is economic.

• 물과 미래
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• 제35권5호
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• pp.51-59
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• 2002

In recent years the human impact on the environment becomes increasing lift threatening, calls for the better management of resources. In field of water quality of river flow, the best way to conserve water quality is specific efforts to control the pollutant loadings and treat the loadings in the basin to reduce the discharge of pollutant loadings to river. But in general the water quality influenced by the dam discharge. Especially in dry season, it is more dominant way to improve the water quality which contaminated with the pollutant loadings from the basin. The dam discharge amounts of the 2 dams in the Keum River that maintain the down stream water quality were estimated for the year of 1999, 2001, 2006, 2011, in case of irrigation and non-irrigation seasons. The pollutant loadings for the basin are estimated with the planning of treatment plants construction schedule for every sub-basins. The river flow rates were considered low flow as 2.33 year low flow and 10 year low flow. The QUAL2E model was used as a tool of simulation.

• 생태와환경
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• 제42권4호
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• pp.487-494
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• 2009

We compared spatial and temporal variations of water chemistry between high-flow year ($HF_y$) and low-flow year ($LF_y$) in an artificial lentic ecosystem of Daechung Reservoir. The differences in the rainfall distributions explained the variation of the annual inflow and determined flow characteristics and water residence time and modified chemical and biological conditions, based on TP, suspended solids, and chlorophylla, resulting in changes of ecological functions. The intense rainfall and inflow from the watershed resulted in partial disruption of thermal structure in the metalimnion depth, ionic dilution, high TP, and high suspended solids. This condition produced a reduced chlorophyll-a in the headwaters due to low light availability and rapid flushing. In contrast, reduced inflow and low rainfall by drought resulted in strong thermal difference between the epilimnion and hypolimnion, low inorganic solids, high total dissolved solids, and low phosphorus in the ambient water. The riverine conditions dominated the hydrology in the monsoon of $HF_y$ and lacustrine conditions dominated in the $HF_y$. Overall data suggest that effective managements of the flow from the watershed may have an important role in the eutrophication processes.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2018년도 학술발표회
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• pp.355-355
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• 2018

Natural hydrology systems, including high flow and low flow events, are important for aquatic ecosystem health and are essential for controlling the structure and function of ecological processes in river ecosystems. Ecosystem responses to flow changes have been studied in a variety of ways, but little attention has been given to how episodic typhoons and atmospheric circulation patterns can change these hydrologic regime-ecological response relationships. In this diagnostic study, we use an empirical approach to investigate the salient features of interactions between atmospheric circulation, climate, and runoff in the five major Korean river basins.

• 한국농공학회논문집
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• 제49권6호
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• pp.11-20
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• 2007

In order to make the way to determine the instream flow more practically, we have investigated many case studies and reviewed reports and papers. To validate instream flow level suggested by the case studies, DAWAST and HEC-RAS model were applied to the Gap-stream watershed in Daejeon city. Flow-duration analysis was performed both with the stream flow data gauged in the Indong, Boksu, and Hoeduck stations, and with the stream flow data estimated by the DAWAST model and the specific discharge method. Instream flow was determined among the flow-duration analysis, DAWAST, HEC-RAS model and mass balance approach. It was satisfied with various factors such as target water quality, water depth for eco-system and resorts, water surface width, flow velocity for landscape in dry season. The study suggested that the mean low flow could be replaced into the instream flow for the preliminary study because the instream flow considering ecosystem, landscape, water-friendly environment and water quality was generally close to the mean low flow.

• Nuclear Engineering and Technology
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• 제45권2호
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• pp.257-264
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• 2013

In Canada Deuterium Uranium (CANDU)-type nuclear power plants, the reactor is composed of 380 fuel channels and refueling is performed on one or two channels per day. At the time of refueling, the fluid force of the cooling water inside the channel is exploited. New fuel added upstream of the fuel channel is moved downstream by the fluid force of the cooling water, and the used fuel is pushed out. Through this process, refueling is completed. Among the 380 fuel channels, outer rows 1 and 2 (called the FARE channel) make the process of using only the internal fluid force impossible because of the low flow rate of the channel cooling water. Therefore, a Flow Assist Ram Extension (FARE) tool, a refueling aid, is used to refuel these channels in order to compensate for the insufficient fluid force. The FARE tool causes flow resistance, thus allowing the fuel to be moved down with the flow of cooling water. Although the existing FARE tool can perform refueling in Korean plants, the coolant flow rate is reduced to below 80% of the normal flow for some time during refueling. A Flow rate below 80% of the normal flow cause low flow rate alarm signal in the plant operation. A flow rate below 80% of the normal flow may cause difficulties in the plant operation because of the increase in the coolant temperature of the channel. A new and improved FARE tool is needed to address the limitations of the existing FARE tool. In this study, we identified the cause of the low flow phenomena of the existing FARE tool. A new and improved FARE tool has been designed and manufactured. The improved FARE tool has been tested many times using laboratory test apparatus and was redesigned until satisfactory results were obtained. In order to confirm the performance of the improved FARE tool in a real plant, the final design FARE tool was tested at Wolsong Nuclear Power Plant Unit 2. The test was carried out successfully and the low flow rate alarm signal was eliminated during refueling. Several additional improved FARE tools have been manufactured. These improved FARE tools are currently being used for Korean CANDU plant refueling.

• 한국수자원학회논문집
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• 제40권2호
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• pp.113-124
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• 2007

갈수량(low flow)은 과거 자연상태 하천에서 갈수기에 흘렀던 유량으로서 자연과 사람이 공유할 수 있는 최소한의 유량이며, 이수측면에서 하천수의 공급능력을 평가하여 취수량을 설정하는 기준 유량이다. 일본과 우리나라에서는 평균갈수량과 기준갈수량을, 미국과 영국 등에서는 10년빈도 7일 갈수량($7Q_{10}$)을 갈수량 지표로 사용하고 있다. 본 연구에서는 위의 세 지표를 관측자료와 모의 생성자료를 이용하여 비교하고 고찰하여 보았다. 갈수량 산정을 위해서는 과거의 관측 유량자료가 필요하나 국내에는 수위관측시설이 한정되어 있을 뿐 아니라 홍수기에 비해 갈수기 자료가 턱없이 부족하여 갈수량 산정에 많은 어려움을 겪고 있다. 국내에서는 대부분 비유량법(drainage-area ratio method)으로 미계측유역의 갈수량을 산정하고 있다 본 연구에서는 미계측유역(ungauged basin)의 갈수량을 산정하기 위한 방법으로 비유량법과 지역회귀기법(regional regression method), 기저유량상관법(baseflow correlation method)을 국내에 적용하여 보고, 각 방법의 적용시 지침과 국내에 적합한 갈수량 산정방법을 제시하였다.