수문곡선 분리를 통한 댐 유입량 평가

정영훈,Jung, Younghun 한국농공학회 2018 한국농공학회논문집 Vol.60 No.3

Understanding the composition of the dam inflow can improve the efficiency of dam operation considering the seasonal characteristics. Hydrograph analysis is one of the methods to identify the characteristics of dam inflow. In addition, baseflow separation on the dam inflow can be affected by anthropogenic influences depending on dam locations. In this regard, the objectives of this study are 1) to analyze yearly and monthly baseflow contribution to the dam inflow and 2) to compare the baseflow contribution to the inflow in dams located upstream and downstream of the watershed. The result shows that the estimated baseflow index was smaller in the upstream dams compared to the downstream dams. Discharge from the upstream water infrastructure including dams and reservoirs can be a part of inflow into the downstream water infrastructure. Based on this scenario, the discharge regulated from the upstream dam could lead to overestimation of baseflow contribution to inflow into the downstream dam. We expect that the results from this study elucidate the role and function of dams and hence, contribute to the efficient operation of dams located in the upstream and the downstream of the watershed.

EVALUATION OF THE WATER RESOURCES ASPECT OF THE OPERATING RESULTS OF THE DAECHEONG MULTIPURPOSE DAM

Noh, Jaek-young Korea Water Resources Association 2004 Water engineering research Vol.5 No.1

This paper evaluated the water resources aspect of the operating results of the Daecheong Multipurpose Dam for the last 21 years. The elements that were evaluated included the amount of water supply from the dam. volume of outflow from the regulating dam, changes in the runoff volume at the dam site and downstream, and variations in the water supply capacity of the Daecheong Multipurpose Dam and the Geum River Barrage Dam situated in the estuary. The rainfall-runoff model was used to evaluate the changes in the runoff volume, and the water balance analysis system was used to evaluate the variations in the dams'water supply capacities. The volume of domestic and industrial water supply from the Daecheong Multipurpose Dam increased to 6.1 times for the last 21 years from 61${\times}$$10^6$$m^3$ in 1981 to 375${\times}$$10^6$$m^3$in 2001. The rate of outflow to inflow of the Daecheong Dam was analyzed 1.30 times in dry season, 1.12 times in semi-dry season, and 0.90 times in rainy season. The volume of inflow to the Geum River Barrage Dam down- stream after the dam's construction increased to 1.25 times in dry season and 1.02 times in semi-dry season and decreased to 0.94 times in rainy season. The water supply capacity of the estuary barrage dam almost did not change in cases with or without the Daecheong Multipurpose Dam, but storages were largely affected by the outflows of the Daecheong Multipurpose Dam.

Seismic fragility analysis of a cemented Sand-gravel dam considering two failure modes

Khadije Mahmoodi,Ali Noorzad,Ahmad Mahboubi 사단법인 한국계산역학회 2020 Computers and Concrete, An International Journal Vol.26 No.6

Dams are vital infrastructures that are expected to maintain their stability during seismic excitations. Accordingly, cemented material dams are an emerging type, which are being increasingly used around the world owing to benefiting from advantages of both earth-fill and concrete gravity dams, which should be designed safely when subjected to strong ground motion. In the present paper, the seismic performance of a cemented sand and gravel (CSG) dam is assessed using incremental dynamic analysis (IDA) method by accounting for two failure modes of tension cracking and base joint sliding considering the dam-reservoir-foundation interactions. To take the seismic uncertainties into account, the dam is analyzed under a suite of ground motion records and then, the effect of friction angle for base sliding as well as deformability of the foundation are investigated on the response of dam. To carry out the analyses, the Cindere dam in Turkey is selected as a case study, and various limit states corresponding to seismic performance levels of the dam are determined aiming to estimate the seismic fragilities. Based on the results, sliding of the Cindere dam could be serious under the maximum credible earthquake (MCE). Besides, dam faces are mostly to be cracked under such level of intensity. Moreover, the results indicate that as friction angle increases, probability of sliding between dam and foundation is reduced whereas, increases tensile cracking. Lastly, it is observed that foundation stiffening increases the probability of dam sliding but, reduces the tensile damage in the dam body.

댐사용권과 댐물 사용료에 관한 법적 분석

정우상 中央大學校 法學硏究所 2011 法學論文集 Vol.35 No.2

Overall dam construction process, dam usage right and tariffs of dam water of Korea have unique legal characteristics, which are not existing in other countries. Tariffs for the usage of dam water are generally regulated by "Act on Dam Construction and Assistance Programs to Dam-Neighboring Areas" and "Korea Water Resources Corporation Act". The definition of 'dam usage right' is the right to use a certain amount of water from a multipurpose dam for specific purposes by securing it in a designated area. Dam usage rights holders who contributed the construction cost of multi-purpose dam or any grantee of those rights from relevant authority shall collect the tariffs from the dam water users. By allowing dam usage right holders to collect tariffs, the effectiveness of the dam usage right shall be increased. There have been disputes regarding charging tariffs for dam water. Tariffs are not only apply to water stored in dam but also to the water in downstream that's discharged from dam. Consequently, it is reasonable that dam usage right holders have the right to make signing a contract with demander of downstream water and thus it enables to perform the purposes of dam usage right. On the other hand charging tariffs do not include below standard droughty flow66). In other words, below standard droughty flow shall not be charged tariffs even though discharged from dam. Paragraph (2), Article 35 in the "Act on Dam Construction and Assistance Programs to Dam-Neighboring Areas" regulates dam usage right holders or any grantee of those rights from relevant authority shall determine the tariffs within the amount of actual expenses that they have spent while considering the quantity of water of users based on article 20, paragraph (1) or the contributed amount under Article 33 a holder of right for dam use or any grantee of those rights from relevant authority. Paragraph (1) of Article 16 in the "Korea Water Resources Corporation Act", however, regulates that tariffs shall be collected from users of water supplied from the facility for the water resources development with considering its construction cost, and O&M(operation and maintenance) of the facility based on the amount used by users. It seems these two acts conflict each other. However, it is reasonable to interpret the article 35 of "Act on Dam Construction and Assistance Programs to Dam-Neighboring Areas" as dam usage right holders shall collect tariffs which include the costs of O&M for multipurpose dam. To increase the effectiveness of the dam usage right which is designed for construction cost recovery, it is critical to interpret the act as collecting tariffs which include the actual expenses spent for O&M for multipurpose dam. By interpreting these two acts through above fashion and logic, a contradiction between "Act on Dam Construction and Assistance Programs to Dam-Neighboring Areas" and "Korea Water Resources Corporation Act" shall be settled.

Geomembranes in Dams : Half-century of Applications for New Construction and Rehabilitation Purposes

D. Cazzuffi,J. Giroud,A. Scuero,G. Vaschetti 한국토목섬유학회 2011 한국지반신소재학회 학술발표회 Vol.2011 No.11

In more than 270 dams worldwide, geomembranes are the main waterproofing component. The geomembrane is generally associated with other geosynthetics performing various functions, thereby forming a geosynthetic barrier. The first application of a geomembrane as the main waterproofing component of a dam dates back to 1959, i.e. more than 50 years ago. In this paper, uses of geosynthetic barriers in the various types of dams are reviewed. The types of dams reviewed include: embankment dams (earthfill and rockfill dams), concrete and masonry dams and roller compacted concrete (RCC) dams. Design and construction aspects are considered, as well as selection of geosynthetic materials and performance (including seepage control and durability). The paper is illustrated using a number of examples of new dams and rehabilitation of existing dams, including examples of the early dams constructed or rehabilitated using geosynthetic barriers in the 1950s, 1960s and 1970s.

안동댐 하류 하천에서 사주의 재현 모의

장창래(Jang Chang-Lae),Shimizu Yasuyuki 대한토목학회 2010 대한토목학회논문집 B Vol.30 No.4B

본 연구에서는 안동댐 하류 하천을 대상으로 댐 건설에 의해 하천의 변화에 미치는 영향을 파악하고, 모래시주의 복원 및 재현 방안을 검토 하였다. 안동댐과 임하댐의 영향으로 댐 하류 하천에서 하상이 저하되고 하상토의 평균 입경이 굵어지는 특성을 보여주고 있으며, 저수로의 수가 증가하였다. 안동댐 건설 후에는 식생의 면적이 약간 증가하고 있으나, 임하댐이 건설되면서부터 식생의 면적이 급격하게 증가되고 있다. 댐 건설에 의해 치수안전도는 재현기간을 비교하여 5에서 10배정도 증가되고, 댐 건설 전과 후의 강턱유량은 2,857 ㎥/s에서 580 ㎥/s로 감소되었다. 또한 평균 하도 폭 및 경사를 이용한 등류조건에서는 댐 건설 전과 후의 강턱유량에 대한 중규모 하상형태의 영역구분은 단열사주와 복렬사주의 중간 영역으로부터 완전한 복렬사주 영역으로 변화하였다. 하상변동 계산에서는 댐 건설 전에 명확한 사주 및 유로가 형성되었고, 댐 건설 후에는 망상유로가 형성되었으며, 댐 건설로 인한 유량의 변화에 의해 사주형상이 변화되는 것을 알 수 있었다. This study examined the physical effects on the river changes downstream of Andong dam and simulated the reproduction of sand bars and the geomorphic changes numerically. The river bed downstream of Aandong dam and Imha dam was decreased and the mean diameter of bed materials was increased, and the number of lower channels was increased. The vegetated area was slightly increased after Andong dam construction. Moreover, the area was abruptly increased after Imha dam construction. The bankfull discharges was estimated to 580 ㎥/s after the dams construction and 2,857 ㎥/s before the dams. A flood mitigation safety by the dams construction considering return period was increased to 5 to 10 times. As a result of meso-scale regime analysis by using banfull discharge, the regime between single bars and multiple row bars before the dams construction was changed to completely the regime of multiple row bars after the dams. The numerical simulation results showed that the sand bars and lower channels were developed before the dams, and braided river was developed after the dams. This meant that the patterns of sand bars was changed by variable discharge due to the dams construction.

A Fast Method to Evaluate upper Region Strength Safety of Gravity Dam

Wen-jie Niu 대한토목학회 2018 KSCE Journal of Civil Engineering Vol.22 No.7

Strength safety problem of concrete gravity dam is a key issue in the dam design process. For purpose of realistic modeling ofconcrete dam, numerical method has achieved a dominant position. However, models need to be tested with filed experience toconvince that they are applicable, and accompanying sophisticated numerical model makes preliminary design and safety evaluationof concrete dam cumbersome and difficult. So we propose a concise method for strength safety evaluation of triangle dam. In the newmethod, we apply upper stream water pressure and dam self weight on the dam model, and use an analytic solution to obtain damstresses in the dam upper region (two thirds of the height of the dam superstructure). Then, we select Ottosen failure criteria todetermine critically stressed locations and safe locations in the dam upper region. We compared the analysis results by the newmethod with simulated results by Ansys, and there is only slight difference. At last, by the new method, we evaluate effect ofgeometry parameters on upper region strength safety of an ideal right triangle dam considering dam self-weight and full upstreamreservoir water pressure. Results indicate that when the dam wedge top corner angle increases, the upper region safety factor ofstrength is enhanced. The proposed fast method would indeed prove desirable and valuable because it is succinct and cost-effectivefor engineers to make preliminary design and strength safety evaluation of concrete dam. And the proposed fast method may also beused to check the analysis results by numerical simulation software.

기후변화에 따른 국내 주요 다목적댐의 유입량 변화 전망

이문환,임은순,배덕효 한국습지학회 2019 한국습지학회지 Vol.21 No.5

다목적댐은 생·공용수를 공급하고, 하천유지유량을 방류하는 등 하천관리에 있어 매우 중요한 역할을 한다. 하지만, 최근 발생하고 있는 기상이변은 댐 공급량의 시공간적 변화를 야기하여 댐 용수공급의 취약성이 증대되고 있는 실정이다. 본 연구에서는 기후변화에 따른 국내 6개 다목적댐들의 미래 유입량의 변화를 평가하였다. 평가를 위해, 고해상도 앙상블 기후변화 시나리오를 이용하였으며, 준분포형 강우-유출모형을 통해 댐 유입량을 산정하였다. 평가 결과, 모든 댐과 모든 시나리오에서홍수량이 크게 증가하는 것으로 나타났다. 하지만, 갈수량의 경우 태백산맥에서 발원되는 소양강댐, 충주댐, 안동댐은 크게감소하는 것으로 나타났으나, 합천댐은 증가하는 것으로 나타났으며, 대청댐과 섬진강댐은 변화가 거의 없었다. 하지만 합천댐을 제외한 나머지 댐들 모두 갈수량의 범위가 더욱 넓어지고, 갈수량의 최소값은 감소하는 등 기후변화는 댐의 공급능력에부정적인 영향을 미칠 것으로 분석되었다. 따라서 기후변화를 고려한 극한 물부족 발생 시 대응할 수 있는 물관리 정책수립이 요구된다. Multi-purpose dams in Korea play a very important role in water management such as supplying water for living, industrial water, and discharging instream flow requirement to maintain the functions of river. However, the vulnerability of dam water supply has been increased due to extreme weather events that are possible linked to climate change. This study attempts to project the future dam inflow of six multi-purpose dams by using dynamically downscaled climate change scenarios with high resolution. It is found that the high flows are remarkably increased under global warming, regardless of basins and climate models. In contrast, the low flows for Soyangang dam, Chungju dam, and Andong dam that dam inflow are originated from Taebaek mountains are significantly decreased. On the other hand, while the low flow of Hapcheon dam is shown to increase, those of Daecheong and Sumjingang dams have little changes. But, the low flows for future period have wide ranges and the minimum value of low flows are decreased for all dams except for Hapcheon dam. Therefore, it is necessary to establish new water management policy that can respond to extreme water shortages considering climate change.

발전용댐 이수능력 평가 연구 (III): 한강수계 발전용댐 가뭄단계별 운영기준 개발 및 효과 분석

정기문,강두선,김태순 한국수자원학회 2022 한국수자원학회논문집 Vol.55 No.7

Integrated water resources management (IWRM) has focused on efficient response to various water related disasters by climate change. In particular, more flexible usage of conventional water resources infrastructures is expected to provide an eco-friendly water management. Multi-purpose dams and water supply dams are well known as water management facilities for securing and supplying water in drought season. Recently, based on the report ‘2021 multi-purpose use of hydropower dams in Han river’, contribution of hydropower dams on water resources management is becoming more significant beyond the traditional role of hydropower generation. In drought conditions, the dams control water supply depending on the pre-defined drought stages. In the case of multi-purpose dams, an operation standard during drought has been already prepared and applied; however, for the hydropower dams, specific standards are not fully prepared yet in South Korea. In this study, a method for calculation of standard water storage and discharge reduction of hydropower dams according to drought stage is newly proposed reflecting the characteristics of hydropower dams. The proposed method was applied to the hydropower dams in Han river, where six hydropower dams are located. A case study of the historical droughts occurred in 2014-2017 demonstrated that the proposed hydropower dam operation rule could improve the water supply stability under severe drought conditions compared to the conventional operations. In the future, the role of hydropower dams for water resources management is expected to become more important, and this study can be widely used for water supply planning such as drought response using hydropower dams. 최근 국내에서는 수량, 수질 등 기후변화로 인한 다양한 수자원 문제에 효율적으로 대응하기 위한 통합물관리 체계가 점차 고도화되고 있으며, 특히 친환경적인 관점에서 이미 개발된 수자원시설물의 탄력적인 활용 방안이 주목받고 있다. 이처럼 용수를 사전에 확보하고, 적시에 공급하기 위한 대표적인 수자원 관리 시설로 다목적댐, 용수전용댐 등이 가장 잘 알려져 있으나, 지난 2021년 ‘한강수계 발전용댐 다목적 활용 협약’을 기점으로 발전용댐 또한 기존의 수력발전 용도를 넘어 수자원 관리 기여도가 한층 높아지게 되었다. 댐에서는 가뭄 발생시 구체적인 가뭄단계 파악 및 용수공급량 조절을 통해 용수공급을 조절해야 한다. 이미 다목적댐 및 용수전용댐의 경우 가뭄대응을 위한 용수공급 운영기준이 마련되어 적용 중에 있으나, 최근에 다목적 활용이 추진된 발전용댐의 경우 구체적인 관련 기준이 마련되어 있지 않은 실정이다. 본 연구에서는 기존 다목적댐 및 용수전용댐 운영기준을 참고하여, 발전용댐의 가뭄단계별 기준저수량 산정 방안 및 용수공급 조정 방안 등을 제시하였다. 제시된 방법은 국내 대부분의 발전용댐이 위치한 한강수계 발전용댐을 대상으로 적용하였으며, 지난 2014~2017년 발생한 가뭄사례를 바탕으로 그 적용 효과를 분석한 결과, 대상 발전용댐의 용수공급 안정성이 개선되는 효과를 확인하였다. 수자원의 효율적인 이용을 위한 발전용댐의 역할은 점차 중요해질 것으로 예상되며, 본 연구 결과는 발전용댐을 활용한 용수공급 관련 연구에 폭넓게 활용될 수 있을 것으로 기대된다.

발전용댐 이수능력 평가 연구(II): 확률론적 유입량을 고려한 발전용댐 용수공급능력 범위 산정

정기문,강두선,김동현,이승오,김태순 한국수자원학회 2022 한국수자원학회논문집 Vol.55 No.7

Identifying the available water resources amount is an essential process in establishing a sustainable water resources management plan. Dam facility is a major infrastructure storing and supplying water during the dry season, and the water supply yield of the dam varies depending on dam inflow conditions or operation rule. In South Korea, water supply yield of dam is calculated by reservoir simulation based on observed historical dam inflow data. However, the water supply capacity of a dam can be underestimated or overestimated depending on the existence of historical drought events during the simulation period. In this study, probabilistic inflow data was generated and used to estimate the appropriate range of the water supply yield of hydropower dams. That is, a method for estimating the probabilistic dam inflow that fluctuates according to climatic and socio-economic conditions and the range of water supply yield for hydropower dams was presented, and applied to hydropower dams located in the Han river in South Korea. It is expected that the understanding water supply yield of the hydropower dams will become more important to respond to climate change in the future, and this study will contribute to national water resources management planning by providing potential range of water supply yield of hydropower dams. 이용 가능한 수자원의 규모를 파악하는 것은 지속가능한 이수계획 수립에 필수적인 과정이다. 특히 댐 시설은 용수를 저류하여 갈수기에 공급하기 위한 주요 수공 시설물로써 댐 유입량 및 댐 운영 방안에 따라 댐의 용수공급능력은 크게 달라질 수 있다. 국내에서는 과거 유입량 관측자료를 바탕으로 저수지 운영모의 방법을 통해 댐 용수공급능력을 산정하고 있으며, 이때 관측기간 내 가뭄발생 여부에 따라 용수공급능력이 과소 혹은 과다 추정되는 불확실성을 내포하며, 이는 수자원 계획 수립의 신뢰도를 저해하는 요인이 될 수 있다. 본 연구에서는 발전용댐의 용수공급능력 적정 범위를 산정하기 위해 확률론적 유입량 자료를 활용하였다. 즉, 다양한 기후 및 사회경제 변화를 반영한 확률론적 댐 유입량 및 이를 활용한 발전용댐 용수공급능력의 범위를 산정하는 방법을 제시하였으며, 국내 한강수계에 위치한 발전용댐을 대상으로 분석을 수행하였다. 향후 기후변화에 대응하기 위한 발전용댐의 용수공급능력 파악은 더욱 중요해질 것으로 예상되며, 본 연구 결과는 다양한 기후 시나리오에서의 댐 용수공급능력 범위를 정량적으로 파악함으로써 국내 수자원 계획 수립에 기여할 것으로 기대된다.