• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.164-164
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• 2011

우리나라는 하상의 평균경사가 급하고 하상계수가 크게 나타나며, 소하천에서의 돌발홍수가 빈발하게 일어나 국내 실정에 적합한 하천 해석 기술을 이용한 바람직한 하천 거동해석이 매우 중요하다고 할 수 있다. 홍수 시 하천의 만곡부나 협착부에서의 흐름은 기본적으로 2차원 흐름으로 서 이 경우 하천 흐름의 수위와 유속 분포는 1차원 하천 모형으로 모의할 수 없다. 특히 우리나라와 같이 하천에 하구둑, 보, 기타 하천 구조물이 많은 경우에는 2차원적인 흐름 해석은 경우에 따라 필수적이다. 본 연구에서는 개발모형인 RAM2 모형을 4대강 살리기 사업이 진행되고 있는 실제유역인 낙동강유역에 적용하여 모형의 적용성을 검증을 위해 그 결과를 실측치와 기존의 법용 프로그램인 RMA-2 모형과 비교하여 모형의 적용성을 입증하였다. 또한 보와 교각과 같은 수공구조물의 설치에 따른 하천흐름의 양상을 파악하기 위하여 RAM2 모형을 달성보 구간에 적용하여 보의 설치 전 후에 대하여 모의를 실시함으로써 모형의 적용성을 입증하였다. 본 연구에 적용된 달성보 구간은 낙동강 살리기 22공구 사업구간으로 중심부에 다기능보가 위치하고 있다. 하천 준설 후, 대상구간 내 보를 설치함으로 인하여 보설치 전 후의 대상구간의 상 하류 하도의 홍수위와 유속분포 등 하천흐름의 양상을 검토하였다. 4대강 살리기 사업에 따라 실제하천의 준설 후 구간내의 전체하도 및 주요 시설물 주위의 하천 흐름을 정확하게 재현하기 위하여 요소망을 조밀하게 구성하고, 안정적인 해를 구하기 위하여 사각형과 삼각형의 복합망으로 낙동강하천정비계획의 측량자료와 GIS프로그램과 SMS를 이용하여 수치모형을 위한 2차원 유한요소망을 구성하였다. 본 연구에서는 보설치 전 후의 대상구간의 상 하류의 홍수위 영향과 유속분포 등 하천흐름의 양상을 연구하기 위하여 대상구간에 대하여 100년 빈도, 500년 빈도의 홍수사상에 대하여 모의를 실시하고 결과를 분석하였다. 하천에서의 흐름, 유사, 오염물 해석을 위한 2차원 유한요소모형은 수자원의 지속적 확보기술의 초석이 될 뿐만 아니라, 필요에 따라서는 하천생태계 보존 및 관리를 위해서도 적용될 수 있어, 수생태계 개선과 친수환경 조성에 크게 기여할 수 있겠다. 또한 하천에서의 흐름, 유사, 오염물 해석을 위한 2차원 유한요소모형을 활용하여 적절한 하천개발 및 관리가 이루어질 경우, 하천의 홍수, 갈수, 환경오염에 따른 사회적인 손실을 방지할 수 있을 것이다.

• Journal of the Korea Institute of Building Construction
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• v.18 no.5
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• pp.447-453
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• 2018

Since 1960, Korea the town center was developed intensively due to rapid industrial development. As a result of the development, the population was concentrated in urban areas and the green area was decreased. Due to the decrease of the green area, the circulation system of the rainwater was changed, hence the rainwater was not introduced into the groundwater., On the other hand, the water on the surface of the road was changed into the water for flowing to the river and evaporation. The changes in the water flow cause many problems, and the depletion of the groundwater does not create an environment in which microorganisms and plants can live. in Korea, permeable pavement construction is increased to solve these problems, but existing pavement blocks have many problems. The pores of the permeable block are clogged due to the accumulation of dust or whitening phenomenon, and the permeability is lost. In this study, the solution of the problems of existing permeable block were suggested by using polymer and artificial permeable pipe, and strength, permeability and service life are increased, The relationship between the substitution rate of the polymer and the mixing ratio of the artificial permeable pipe was analyzed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.2
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• pp.261-268
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• 2018

The study used the simplified flooding analysis model, SIMOD, to distribute the total flood discharge by time, so research on flooding in urban areas can be conducted. The conventional flooding analysis models have limitations in constructing input data and take a long time for analysis. However, SIMOD is useful because it supports rapid decision-making process using quick modeling based on simple hydrological data, such as topography and inflow flood of the study area, to analyze submerged routes formed by flooding. Therefore, the study used the SIMOD model to analyze flooding in urban areas before conducting a comparative study with the outputs from FLO-2D, which is one of the conventional flooding analysis models, to identify the model's applicability. Seongseoje was selected as the study area, as it is located downstream the Geumho river where streams flow in the adjacent areas, and dikes are high enough to apply the "Overflow and Break" scenario for urban areas. With regard to topography, the study applied DEM data for the conventional flooding analysis and DSM data to represent urban building communities, distribution of roads, etc. Input flood discharge was calculated by applying the rectangular weir equation under the bank and break scenario through a 200-year return period of a design flood level. Comparative analysis was conducted in a flooded area with a simulation time of 1-24 hours. The time for the 24-hour simulation in SIMOD was less than 7 minutes. Compared with FLO-2D, the difference in flooded areas was less than 20%. Furthermore, the study identified the need for topography data using DSM for urban areas, as the analysis result that applies DSM showed the influence of roads and buildings.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1048-1052
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• 2007

그동안의 하천 유량자료는 주로 홍수방어를 목적으로 구축되어진 관계로 대부분 홍수기에만 의미있는 자료를 갖추고 있으며, 환경관리에 필요한 저갈수기 유량자료는 그 신뢰도가 매우 떨어지고 있다. 다행히 지난 2004년 하반기부터 4대강 물환경 연구소에서 직접 오염총량관리 단위유역 말단부에서 8일 간격으로 유량과 수질을 동시에 측정하기 시작하였고, 사업의 결과 건기 우기의 구별 없이 연중 일정한 간격으로 하천유황 및 수질의 변동여부를 확인하는 것이 가능하게 되었으나, 각 단위유역별 유황곡선을 작성할 목적으로 8일 간격 유량자료를 사용할 수 없다는 단점이 있다. 즉, 현재 관측 중인 8일 간격 유량자료만으로는 동시 관측이 진행 중인 수질항목과 유량 사이의 상관관계 정도를 파악한다거나, 어떤 방법으로든 수문모형을 구축한 후 이를 부분적으로 검정할 때 참고자료로 사용하는 정도로 그 용도가 한정될 수밖에 없는 실정이다. 이에 본 연구에서는 낙동강 오염총량관리 41개 단위유역 전체를 대상으로 관측된 8일 간격 유량자료를 이용하여 이를 1일 간격 유량자료로 확장을 시도하였다. 이를 위하여 기존의 TANK 모형에 하도추적기능을 추가한 보다 진보된 TANK 모형을 구성하였다. 낙동강 단위유역별 취수량과 방류량을 바탕으로 한 물수지 자료 또한 구비하여 모형에 고려되도록 하였다. 모형의 매개변수 추정을 위하여 국립환경과학원 낙동강물환경연구소에서 8일 간격으로 관측한 유량자료가 이용되었다. 분석결과 모의된 일유량이 실제 유량을 비교적 잘 재현하는 것으로 나타남에 따라 8일간격 유량관측자료의 일유량으로의 확장 가능성을 확인할 수 있었다. 구축된 모형은 적용에 앞서 10년 평균 저수량을 기준으로 1차 오염총량관리 기준유량과의 비교를 시도하였으며, 상류 댐 방류의 영향 및 물수지의 영향을 배제한 상태의 자연유량을 산정하여 이를 현재 유황과의 비교를 수행하였다. 현재유량과의 비교 결과 다목적 댐의 방류효과로 인한 유량 증가효과 및 대규모의 취수로 인한 유량 감소효과가 뚜렷하게 나타남을 알 수 있었다. 산정된 자연유량을 통하여 비유량을 산정한 결과 $5,000km^2$이하인 유역 면적의 경우 비유량 $0.0048m^3/s/km$를, $5,000km^2$이상인 경우에는 비유량 $0.0043m^3/s/km$를 적용하는 것이 바람직할 것으로 분석되었다. 여기에 유역의 물이용 및 상류의 댐 방류 효과가 고려되면 실제 유역의 저수량을 개략적으로 산정할 수 있을 것으로 기대된다.

• Journal of Korea Water Resources Association
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• v.43 no.2
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• pp.211-220
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• 2010

The objective of this paper presents the application of an "integrated urban flood modeling-runoff model, urban flood model and sewer system model-" in a highly urbanized area of Samcheok where is seriously inundated in 2002 and 2003. For this, we demonstrate how couple a 1-D hydrodynamic model of the river, a 2-D hydrodynamic model of the overland (surface) flow, and a sewer network model including each boundary conditions. In order to make data file for the model, topographic information like elevation and share rate of buildings are directly extracted from DEM or topographical source data without data exchange to avoid uncertainty errors. Furthermore, the research is to assess the impacts of Manning n and buildings influences to inundated depth by changing its share ratio from 10 % to 30 % in low-land urban area. As a results, we found out that the urban inundated depth was decreased by Manning n but increased by buildings ratio. The calculated results of inundation was similar with observed one in 2002 and 2003 flooding. Furthermore, the area was also inundated under not riverbank break case in 2002 flooding.

• Journal of Korea Water Resources Association
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• v.47 no.3
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• pp.257-267
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• 2014

The impact of the combination of changes in temperature and rainfall due to climate change on surface water resources is important in hydro-meteorological research. In this study, 4 hydro-meteorological (HM) models from the Rainfall Runoff Library in the Catchment Modeling Toolkit were used to model the impact of climate change on runoff in streams for 5 river basins in the Republic of Korea. Future projections from 2021 to 2040 (2030s), 2051 to 2070 (2060s) and 2081 to 2099 (2090s), were derived from 12 General Circulation Models (GCMs) and 3 representative concentration pathways (RCPs). GCM outputs were statistically adjusted and downscaled using Long-Ashton Research Station Weather Generator (LARS-WG) and the HM models were well calibrated and verified for the period from 1999 to 2009. The study showed that there is substantial spatial, temporal and HM uncertainty in the future runoff shown by the interquartile range, range and coefficient of variation. In summary, the aggregated runoff will increase in the future by 10~24%, 7~30% and 11~30% of the respective baseline runoff for the RCP2.6, RCP4.5 and RCP8.5, respectively. This study presents a method to model future stream-flow taking into account the HM model and climate based uncertainty.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5636-5645
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• 2015

Physical characteristics of aggregates affect the workability and strength of mortar and concrete, which include their fineness ratio, particle size distribution and water absorption. The workability of construction materials decreases if the incorporated fine aggregates show improper size distribution of their particles. This study shows the particle size effect on the rheological behavior of mortar and provides basic information for evaluating its workability. A mini-slump flow test was adopted to evaluate the workability of mortar. In addition, its plastic viscosity and yield stress were measured using a rheometer for building materials. The sand samples were prepared by sieving river sand and sorting out with their particle sizes. As a result, it was observed that the fines less than 0.7 mm increases the yield stress and plastic viscosity of the mortar samples. If the fines are less than 0.34 mm, the water absorption of the fines dominates change on the workability.

• Korean Journal of Ecology and Environment
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• v.44 no.2
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• pp.226-238
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• 2011

Ichthyological fauna and community structure were surveyed in the Naeseong Stream around the planed Yeongju Dam, Yeongju City, Gyeongsangbuk-do from April 2007 to October 2009, During the survey period, 27 species (25 genera, 10 families) were collected. Cyprinid fish comprised 63.0% (17 species) and cobitid fish comprised 7.4% (2 species). Ten of the 27 species (37.0%) were endemic species. The dominant and subdominant species based on the number of individuals was Zacco platypus (43.2%) and Zacco koreanus (15.8%), respectively. Introduced from the other native rivers and exotic fish were Opsariichthys uncirostris amurensis, Leiocassis ussuriensis, and Micropterus salmoides (11.1%). The declining population density of Zacco koreanus and its subdominant status represents a change, since, up until the mid 1990's, it was widely distributed throughout the area and was the dominant species. The distribution area of Zacco koreanus decreased in size; by 2009, it no longer inhabited the lower reaches of the Naeseong Stream. On the other hand, Zacco platypus remained the dominant species throughout the area, except for the upper-reaches of the water-course. Gobiobotia naktongensis inhabited all areas of Naeseong Stream, which mainly has a sandy bottom. Analyses of the fish community revealed species diversity, even-ness and dominant indices were 0.881, 0.615, and 0.230 respectively. These results showed that the main river, in which the water width and flow are abundant and which has various habitats, has a higher species diversity (0.829) than the tributary (0.735).

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.4
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• pp.1-12
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• 2020

The extreme 2017 spring drought affected a large portion of South Korea in the Southern Gyeonggi-do and Chungcheongnam-do districts. This drought event was one of the climatologically driest spring seasons over the 1961-2016 period of record. It was characterized by exceptionally low reservoir water levels, with the average water level being 36% lower over most of western South Korea. In this study, we consider drought response methods to alleviate the shortage of agricultural water in times of drought. It could be to store water from a stream into a reservoir. There is a cyclical method for reusing water supplied from a reservoir into streams through drainage. We intended to present a decision-making plan for water supply based on the calculation of the quantity of water supply and leakage. We compared the rainfall-runoff equation with the TANK model, which is a long-term run-off model. Estimations of reservoir inflow during non-irrigation seasons applied to the Madun, Daesa, and Pungjeon reservoirs. We applied the run-off flow to the last 30 years of rainfall data to estimate reservoir storage. We calculated the available water in the river during the non-irrigation season. The daily average inflow from 2003 to 2018 was calculated from October to April. Simulation results show that an average of 67,000 tons of water is obtained during the non-irrigation season. The report shows that about 53,000 tons of water are available except during the winter season from December to February. The Madun Reservoir began in early October with a 10 percent storage rate. In the starting ratio, a simulated rate of 4 K, 6 K, and 8 K tons is predicted to be 44%, 50%, and 60%. We can estimate the amount of water needed and the timing of water pump operations during the non-irrigation season that focuses on fresh water reservoirs and improve decision making for efficient water supplies.

• Journal of the Korean Society of Hazard Mitigation
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• v.6 no.3 s.22
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• pp.69-76
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• 2006

An hydraulic and hydrologic analysis procedure was proposed to reduce the inundation damage of highway in urban stream, that could contribute the EAP and Traffic control planning of Dongbu highway in the Jungrang stream basin which is one of the representative urban area in Korea. We performed the HEC-HMS runoff analysis, and the UNET unsteady flow modeling to decide the inundation reaches and their characteristics. The high inundation risk areas were of Emoon railway bridge and the Wollueng bridge, which are inundated in the case of 10 year and 20 year frequency flood respectively. We also analyze the inundation characteristics under the various conditions of the accumulation rainfall and the duration. Flood elevation at the Wolgye-1 bridge exceed over Risk Flood Water Level(EL.17.84 m) when the accumulation rainfall is over 250 mm and shorter duration than 7 hr. When neglecting backwater effect from the Han river, inundation risk are highly at the reach C2(Wolgye-1 br. ${\sim}$Jungrang br., left bank), C1(Wolgye-1 br. ${\sim}$Jungrang br., right bank), D(Jungrang br. ${\sim}$Gunja br.) in order, but when consider the effect, the inundation risk are higher than the others at the reach D2(Jungrang br. ${\sim}$Gunja br., left bank) and E(Gunja br. ${\sim}$Yongbi br.), which are located downstream near confluence.