• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2012년도 학술발표회
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• pp.11-17
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• 2012

The Waikato River is New Zealand's longest River, though relatively small on international scales. It drains the central North Island and has New Zealand's largest lake (Lake Taupo) at its headwaters. The upper reaches have sustained flows fed by large aquifers which are recharged by rainfall events providing relatively constant river flows, whereas the lower reaches respond more directly to rainfall events having more peaky flows after rainfall and extreme low flows during dry periods. Consumptive allocation from the river is relatively low with only about 3% of the mean annual flow being allocated. However, more than seven times the river's flow is allocated for non-consumptive purposes before discharging to the Tasman Sea. The majority of this non-consumptive allocation is for hydro power generation and as cooling water at both thermal and geothermal power stations which produce up to 25% of New Zealand's electricity. The upper half of the river has been heavily modified with the construction of eight dams for power generation. This has resulted in a succession of cascading dams replacing the previously uncontrolled river. The Waikato River also provides drinking water for Auckland City (NZ's largest city) and Hamilton City (NZ's 4th largest city). In recent years there has also been considerable growth in water requirements for pasture irrigation to support the intensification of dairy farming in the catchment. Operators of the power stations are concerned that any further consumptive allocation will further reduce their ability to generate electricity. The Waikato Regional Council, who is charged with managing the river and allocation of water, has recently set new rules for managing the conflicting allocation demands on the Waikato River. This has resulted in an end to further allocation of water where it results in a loss of water for electricity generation from renewable resources (fresh water and geothermal water). The exception to this is the prioritisation of water for municipal supplies ahead of other consumptive uses such as industries and irrigators.

• Structural Engineering and Mechanics
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• 제68권6호
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• pp.747-760
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• 2018

In the present study, a methodology for developing fragilities of arch concrete dams to assess their performance against seismic hazards is introduced. Firstly, the probability risk and fragility curves are presented, followed by implementation and representation of the way this method is used. Amirkabir arch concrete dam was subjected to non-linear dynamic analyses. A modified three dimensional rotating smeared crack model was used to take the nonlinear behavior of mass concrete into account. The proposed model considers major characteristics of mass concrete. These characteristics are pre-softening behavior, softening initiation criteria, fracture energy conservation, suitable damping mechanism and strain rate effect. In the present analysis, complete fluid-structure interaction is included to account for appropriate fluid compressibility and absorptive reservoir boundary conditions. In this study, the Amirkabir arch concrete dam is subjected to a set of 8 three-component earthquakes each scaled to 10 increasing intensity levels. Using proposed nonlinear smeared crack model, nonlinear analysis is performed where the structure is subjected to a large set of scaled and un-scaled ground motions and the maximum responses are extracted for each one and plotted. Based on the results, fragility curves were plotted according to various and possible damages indexes. Discrete damage probabilities were calculated using statistical methods for each considered performance level and incremental nonlinear analysis. Then, fragility curves were constructed based on the lognormal distribution assumption. Two damage indexes were introduced and compared to one another. The results indicate that the dam has a proper stability under earthquake conditions at MCE level. Moreover, displacement damages index is more conservative and impractical in the fragility analysis than tensional damage index.

• Computers and Concrete
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• 제18권6호
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• pp.1153-1173
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• 2016

According to deformation data measured in some high concrete dams, for dam body deformation, there is a complex relationship with dam height and water head for different projects, instead of a simple monotonic relationship consistently. Meanwhile, settlement data of some large reservoirs exhibit a significant deformation of reservoir basin. As water conservancy project with high concrete dam and large storage capacity increase rapidly these decades, reservoir basin deformation problem has gradually gained engineers' attentions. In this paper, based on conventional analytical method, an improved analytical method for high concrete dam is proposed including the effect of reservoir basin deformation. Though establishing FEM models of two different scales covering reservoir basin and near dam area respectively, influence of reservoir basin on dam body is simulated. Then, forward and inverse analyses of concrete dam are separately conducted with conventional and proposed analytical methods. And the influence of reservoir basin deformation on dam working behavior is evaluated. The results of two typical projects demonstrate that reservoir basin deformation will affect dam deformation and stress to a certain extent. And for project with large and centralized water capacity ahead of dam site, the effect is more significant than those with a slim-type reservoir. As a result, influence of reservoir basin should be taken into consideration with conducting analysis of high concrete dam with large storage capacity.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.1252-1258
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• 2005

The coarse grained materials which is produced in the domestic stony mountains are used as principle materials in the construction sites such as dams, ports, pavement structures and etc. Despite using of various fields like this, There is few apparatuses to experiment these materials in the country. some design parameters of the structures until these days was used from the result of former research abroad. Hereupon, We have developed the large scale direct shear test apparatus and we conduct research in order to get a shear strength of the coarse grained materials from the domestic stony mountains in Kyuong-gi, Choong-chung and Kyoung-sang province. As results of the test, it was revealed that the internal friction was ranging from $38.6^{\circ}$ to $44.5^{\circ}$ and the cohesion was from $1.1kg/cm^2$ to $1.7kg/cm^2$ depending on the local rock conditions.

• 환경영향평가
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• 제13권6호
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• pp.307-314
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• 2004

Among large developmental projects, those of the government and public institutions with the total budget of more than 50billion wons can be executed only when the feasibility of the project has been testified through the procedure of preliminary feasibility study. Multi-purpose dams are public structures that can supply water, produce electricity, and control flood, they belong to large national projects that require legal evaluation procedures such as preliminary feasibility study and environmental impact assessment(EIA). The index that should be considered to be important in dam plan is the migration of residents in submerged district. The importance in the preliminary feasibility study is 4.93 points(98.6 in the scale of 100 at maximum). Among the 12 assessment elements of the policy and economy in the preliminary feasibility study, the element of environment assessment is turned out to be 4.68 points in the assessment importance (93.5 in the scale of 100 at maximum), which is the second in the total ranking and the first in the field of policy, indicating that the element is very important in dam construction planning.

• 한국농공학회논문집
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• 제58권4호
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• pp.21-35
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• 2016

This study is to evaluate the applicability of SWAT (Soil and Water Assessment Tool) model for multi-purpose dams and multi-function weirs operation in Namhan river basin ($12,577km^2$) of South Korea. The SWAT was calibrated (2005 ~ 2009) and validated (2010 ~ 2014) considering of 4 multi-purpose dams and 3 multi-function weirs using daily observed dam inflow and storage, evapotranspiration, soil moisture, and groundwater level data. Firstly, the dam inflow was calibrated by the five steps; (step 1) the physical rate between total runoff and evapotranspiration was controlled by ESCO, (step 2) the peak runoff was calibrated by CN, OV_N, and CH_N, (step 3) the baseflow was calibrated by GW_DELAY, (step 4) the recession curve of baseflow was calibrated by ALPHA_BF, (step 5) the flux between lateral flow and return flow was controlled by SOL_AWC and SOL_K, and (step 6) the flux between reevaporation and return flow was controlled by REVAPMN and GW_REVAP. Secondly, for the storage water level calibration, the SWAT emergency and principle spillway were applied for water level from design flood level to restricted water level for dam and from maximum to management water level for weir respectively. Finally, the parameters for evapotranspiration (ESCO), soil water (SOL_AWC) and groundwater level fluctuation (GWQMN, ALPHA_BF) were repeatedly adjusted by trial error method. For the dam inflow, the determination coefficient $R^2$ was above 0.80. The average Nash-Sutcliffe efficiency (NSE) was from 0.59 to 0.88 and the RMSE was from 3.3 mm/day to 8.6 mm/day respectively. For the water balance performance, the PBIAS was between 9.4 and 21.4 %. For the dam storage volume, the $R^2$ was above 0.63 and the PBIAS was between 6.3 and 13.5 % respectively. The average $R^2$ for evapotranspiration and soil moisture at CM (Cheongmicheon) site was 0.72 and 0.78, and the average $R^2$ for groundwater level was 0.59 and 0.60 at 2 YP (Yangpyeong) sites.

• 한국수자원학회논문집
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• 제42권8호
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• pp.643-657
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• 2009

홍수기에 집중되는 유출량을 갈수기에 적절히 활용하기 위한 대표적인 구조물이 댐이다. 제한된 용수공급량을 적절히 분배해 용수수요량을 만족시키면서 미래 갈수기시 용수공급을 대비하여 댐 저류량을 조절하는 것이 댐 운영의 중요한 목적 중 하나이다. 본 연구에서는 갈수 시 댐 저류량에 따라 댐 계획방류량을 일정비율 줄여주는 Hedging Rule을 5단계로 적용하여 댐의 상시만수위 저류량에 대한 실제 저류량의 편차, 수요에 대한 용수공급 부족량, 그리고 하천유지용수 부족량을 목적함수로 하여 혼합정수 선형계획법(MILP, Mixed Integer Linear Programming)으로 저수지 연계운영모형을 구성하였다. 한강수계의 다목적댐인 충주, 횡성, 소양강 댐과 용수전용댐인 광동 댐, 그리고 발전용 댐이지만 비교적 큰 저류용량을 가진 화천 댐을 연계 운영 대상으로 하여, 수자원장기종합계획에 사용된 2003년 유출량 및 수요량 자료와 댐 운영 실무편람의 댐 계획방류량 자료를 10일 단위로 입력하여 GAMS/CPLEX를 이용해 최적화하였다. 그 결과 생공용수 수요량 99.99%, 농업용수 수요량 99.91%, 그리고 하천유지용수 수요량 100.00%를 충족시키면서도, 실제 2003년 운영자료에 비교하여 댐 저류효율이 10.04% 개선된 결과를 도출하였다.

• 한국지반환경공학회 논문집
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• 제21권10호
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• pp.11-16
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• 2020

우리나라의 농업용 저수지는 국가 주요 기반시설 중 하나로 국민의 삶에 중요한 역할을 수행하고 있다. 하지만 노후화된 저수지가 인명과 재산에 대한 위험 요소로 작용하고 있는 실정이다. 현재 전국에 40년이 넘은 노후화가 진행된 크고 작은 댐과 저수지가 건설되어 있다. 전국에 건설된 댐, 저수지의 관리주체는 여러 기관으로 나눠져 있다. 따라서 비용과 시간적 문제로 모든 댐, 저수지의 관리가 어려운 실정이다. 그렇기 때문에 적은 관리 인력과 전문지식이 부족한 현장의 관리자도 다수의 저수지에 대하여 위험요인을 신속히 파악하고 시설물을 상태를 파악할 수 있는 소규모 저수지에 최적화된 안정성 평가 시스템이 구축되어야 한다. 본 연구에서는 위험인자로 침투, 누수, 침하, 활동, 균열, 침식으로 항목들을 선정하였으며 항목들의 위험도를 평가하기 위해 다기준 의사결정(Multi-Criteria Decision Making : MCDM) 방법 중 하나인 계층적 분석 과정(AHP) 기법을 활용하였다. 분석 결과 침투, 누수, 균열, 활동, 침하, 침식 순으로 나타났다. 산정된 가중치를 활용하여 사전에 간편한 방법으로 댐 저수지 붕괴 위험도를 평가하여 정밀진단 우선순위를 결정 할 수 있을 것으로 판단된다.

• 한국수자원학회논문집
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• 제42권2호
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• pp.161-168
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• 2009

본 연구에서는 팔당댐 지점을 중심으로 상류에 위치하고 있는 소양강, 충주 다목적댐 운영에 따른 빈도홍수량의 거동변화를 분석하고자 하였다. 이를 연구하기 위해서는 동일기간의 댐운영 여부에 따른 두 계열(조절유량, 비조절 유량)의 홍수량 자료를 합리적으로 획득하는 것이 무엇보다 중요하다. 홍수량 산정을 위해서는 단기 강우-유출모형을 이용해야 하지만, 계산의 어려움과 유역의 비선형으로 인해 그 결과를 증명하기 매우 어려운 현실이다. 따라서 상대적으로 유역면적이 클수록 일유량과 홍수량의 관계가 비교적 일정한 경향을 보인다는 점에 착안하여, 장기유출모형인 SWAT-K를 이용하여 댐운영 여부에 따른 두 계열의 일유량을 모의하였다. 일유량과 홍수량의 상관관계로 모의된 일유량을 홍수량으로 유도한 후, 댐운영 여부에 따른 빈도홍수량의 변화특성을 파악하였다. 홍수빈도분석을 위해 사용된 분포는 Extreme Type-I이며, 매개변수 추정은 L-moment 방법을 이용하였다. 연구결과에 따르면, 소양강, 충주 두 다목적댐 운영이 이루어지지 않은 상황에 대한 팔당댐 지점에서의 100년 빈도홍수량에 비하여, 소양강댐, 충주댐, 소양강과 충주댐의 운영유무에 따른 3가지 시나리오에 대한 빈도홍수량은 각각 91, 83, 71 % 규모로 분석되었다. 본 연구는 유역면적이 상대적으로 넓은 유역에서 댐운영 여부에 따른 빈도홍수량의 변화를 파악할 수 있는 새로운 시도였다. 이는 일유량 자료의 이용 및 분석에 있어 이수적인 측면뿐만 아니라 치수적인 측면에서의 활용성을 높일 것으로 판단된다.

• 한국수자원학회논문집
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• 제48권6호
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• pp.511-522
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• 2015

본 연구에서는 한강유역을 대상으로 관측홍수량 자료의 불확실성이 홍수빈도분석 결과에 미치는 영향을 평가하고자 하였다. 이를 위해 한강유역 내의 17개 수위관측지점의 홍수량 자료를 이용하여, 지역홍수빈도분석을 수행한 결과인 지수홍수와 분위수를 중심으로 정량적인 평가를 수행하였다. 연구결과는 관측자료의 특성에 따라 3가지 경우로 분류하여 분석하였다. 첫 번째로 수위자료의 영향을 파악하기 위해 평창강 유역의 수위관측지점을 대상으로 지역홍수빈도분석 결과를 분석하면, 평균홍수량에 대한 오차는 0.240으로 평가되었다. 두 번째로 레이팅 적용에 따른 관측자료의 불확실성이 지역홍수빈도분석 결과에 미치는 영향을 분석하였다. 해당연도에 개발된 레이팅을 각각 적용한 결과와 가장 최근 개발된 레이팅을 적용한 결과를 분석해보면, 평균홍수량에 대한 오차는 평균 0.246으로 평가되었다. 마지막으로 인위적으로 유량이 조절된 댐하류의 통제된 흐름영역에서의 지역홍수빈도 분석 결과를 유추하였다. 댐하류에서의 홍수량 거동은 댐운영에 의해 조절된 것으로 댐상류의 자연유역에서의 비유량 지역화 결과를 연장할 경우, 댐하류의 조절유역에서의 비유량 거동과 큰 차이를 나타내었다.