Multipurpose Dam Research Articles

Water resource policies and management in Korea

Although the annual precipitation in Korea is 30% higher than the world average, increased population, urbanization and industrialization, as well as improved living standard have caused problems such as water shortage, flood damage, and water pollution. Additional multi-purpose dams and infra-structures are supposed to be constructed by 2011. On the other hand, water demand control is also suggested. This includes water saving by increasing water price, reuse of treated water, development of new water resources and rainfall management. Beside the Comprehensive Measures on the Provision of Clean Water, Comprehensive Water Quality Management Measures for the Four Major Rivers and Act on Watershed Management and Community Support are the main policies to be implemented for improving the quality of major rivers. Recently, Total Water Pollution Load management is voluntarily pursued for sustainable management of water resources.

The Rufiji River flood: plague or blessing?

The building of a large multipurpose dam is planned at Stiegler's Gorge on the Rufiji River (Tanzania). Both national and local authorities have strongly emphasised the flood control aspect of the dam as they see the Rufiji floods as a major constraint to development. Though it is true that the Rufiji River has a high flow variability at various timescales, the flood perception in local communities differs from this view. The floods, essential for the sustenance of floodplain fertility, and therefore of the farming system, and vital to the productivity of most of the natural resources on which local communities depend, are perceived as a blessing, whilst droughts and the absence of regular flooding are perceived as the main threat. Historically, most of the food shortages in Rufiji District are associated with drought years and the myth of "the flood as a plague" emerged only in the late 1960s during the Ujamaa villagisation policy. The persistence of this myth is favoured by the inadequate assessment of the complexity of the local economies by the District technical staff. This difference in perception of the flood has major implications for development options. Under the current dam design, the alteration of the flooding pattern would have negative consequences for the downstream wetland and forest ecosystems and the flood-associated livelihoods of some 150,000 people. A cost-benefit analysis of flood control measures and a study of a dam design that would maintain the beneficial aspects of flooding should be accorded the highest priority.

RRFS에 의한 금강수계의 주요지점별 유역유출지표 개발

In this study, we attempted to develop a watershed runoff index subject to main control points by dividing the Geum River basin into 14 sub-basins. The Yongdam multipurpose dam Daecheong multipurpose dam and Gongju gage station were selected to serve as the main control points of the Geum River basin, and the observed flow of each control point was calculated by the discharge rating curve, whereas the simulated flow was estimated using the Rainfall Runoff Forecasting System (RRFS), user-interfaced software developed by the Korea Water Corporation, based on the Streamflow Synthesis and Reservoir Regulation (SSARR) model developed by the US Army Corps of Engineers. This study consisted of the daily unit observed flow and the simulated flow of the accumulated moving average flow by daily, 5-days, 10-days, monthly, quarterly and annually, and normal monthly/annually flow. We also performed flow duration analysis for each of the accumulated moving average and the normal monthly/annually flows by unit period, and abundant flow, ordinary flow, low flow and drought flow estimated by each flow duration analysis were utilized as watershed runoff index by main control points. Further, as we determined the current flow by unit period and the normal monthly/annually flow through the drought and flood flow analysis subject to each flow we were able to develop the watershed runoff index in a system that can be used to determine the abundance and scarcity of the flow at the corresponding point.

Direct and indirect economic impacts of the Bhakra multipurpose dam, India

AbstractThis paper presents results of a study on the direct and indirect economic impacts of the Bhakra multipurpose dam system in the northern part of India that has provided direct benefits in terms of hydropower, irrigated agriculture, water supply, flood control and drought prevention. These direct outputs from the Bhakra dam system have, in turn, generated (i) inter‐industry linkage impacts, both backward and forward linkages, resulting in increase in the demand for outputs of other sectors, and (ii) consumption‐induced impacts arising out of increases in income and wages generated by the direct outputs of the dam. Such indirect economic impacts, quantified by using a fixed‐price multiplier model based on a social accounting matrix (SAM) for Punjab, give a multiplier value of 1.90, indicating that for every rupee (Rs = 100 paise)1 of additional value added directly by the project in the agricultural and electricity sectors, another Rs 0.90 (90 paise) is generated in the form of downstream or indirect effects. The results on income distribution show that the gains to agricultural labour households from the dam have been higher than the gains to other rural households and to urban households. Copyright © 2007 John Wiley & Sons, Ltd.

기후변화 영향평가를 위한 월 물수지모형의 적용성 검토

This study attempted to determine a suitable hydrologic model for assessing the impact of climate change on water resources, and to assess the accuracy of streamflow scenarios simulated by the selected hydrologic model using the meteorological scenarios of the Seoul National University Regional Climate Model(SNURCM). Comparison of four water balance models and two daily conceptual rainfall-runoff models for the simulation capability of the Daecheong Dam inflow indicated that the abcd model performs the best among the tested water balance models and performs as well as SSARR that is popular as a daily rainfall-runoff model in Korea. Parameters of the abcd model were then estimated for 12 ungauged subbasins of the Geum River by the regionalization method. The model parameters were first calibrated at nine multi-purpose dams and were then regionalized using catchment characteristics for another four multi-purpose dams, which were assumed to be ungauged sites. The model efficiency(ME) coefficients of the simulated inflows for these four dams were at least 87%. The MEs of the hindcasted meteorological rainfall scenarios of the 12 subbasins of the Geum River were more than 60%. Moreover, the ME of the Daecheong Dam inflow simulated by the abcd model using the SNURCM rainfall scenarios was more than 80%. Therefore, this research concluded that the abcd model coupled with the SNU-RCM meteorological scenarios can be used for impact assessment studies of climate change on water resources.

Delayed influence of dam storage and discharge on the determination of seasonal proliferations of Microcystis aeruginosa and Stephanodiscus hantzschii in a regulated river system of the lower Nakdong River (South Korea)

This study presents the relationship between the dam hydrology and phytoplankton proliferations in a regulated river system in East Asia. A long-term ecological study reveals that multi-purpose dam regulation on river flow in the Nakdong River (South Korea) affects proliferating patterns of phytoplankton, especially during summer (June–August) and winter (December–next February) as Microcystis aeruginosa and Stephanodiscus hantzschii, respectively, dominate each season by over 80%. Eutrophication was observed in the lower Nakdong River (South Korea) (mean±standard deviation: nitrate-N, 2.8±0.9 mg L −1; phosphate-P, 40.3±31.3 μg L −1; chlorophyll a, 45.2±84.9 μg L −1; n=449), and the limnological characteristics responded to climatic variations such as monsoon and summer typhoons. The river basin experiences concentrated rainfall during the rainy season (June–September, over ca. 60% of total annual rainfall). Correlation and cross-correlation for time-delayed relationship revealed the hydrological environments (i.e., quantity of dam storage and discharge) had significantly negative relationship with the population dynamics of the two bloom-forming species for up to the next 2 years. S. hantzschii had clearer relationship with dam storage and discharge, which might be due to the seasonality exhibited by the species. The results support the necessity of “smart flow control” which may enable destruction of bloom formation by the two species with an adequate pulse of discharge generated by upstream dams in the far-east Asian river systems. This would increase the efficiency of water resource management system.

Combining Rainfall-Runoff Model Outputs for Improving Ensemble Streamflow Prediction

This study reviewed various combining methods that have been commonly used in economic forecasting, and examined their applicability in hydrologic forecasting. The following combining methods were investigated: The simple average, constant coefficient regression, switching regression, sum of squared error, and artificial neural network combining methods. Each method combines ensemble streamflow prediction (ESP) scenarios of the existing rainfall-runoff model, TANK, those of the new rainfall-runoff model that has been developed using an ensemble neural network for forecasting the monthly inflow to the Daecheong multipurpose dam in Korea. In addition to the combining, the ESP scenarios were adjusted using correction methods, such as optimal linear and artificial neural network correction methods. Among the tested combining methods, sum of squared error (SSE), a combining method using time-varying weights, performed best with respect to the root mean square error. When SSE was coupled with optimal linear cor...

Electricity production opportunities from multipurpose dams (case study)

The hydropower is the leading source of renewable energy. It provides more than 97% of all electricity generated by renewable sources. The main advantage of hydro systems is elimination of the cost of fuel. Hydropower on a small-scale is in most cases “run-of-river”, with no dam or water storage, and is one of the most cost-effective and environmentally benign energy technologies to be considered both for rural electrification in less developed countries and further hydro developments in Europe. Multipurpose dams, like Porsuk Dam in Eskisehir, are constructed with the aim of supplying domestic, irrigation and industrial water except electricity generation. Porsuk basin has suitable valley in upstream of existing Porsuk Dam for realizing of small reservoirs. The discharge capacity of Porsuk River is appropriate only to install Small Hydropower Plants (SHPs). For the sustainable management of Porsuk River water, except existing Porsuk Dam, it is required to construct a few new dams on this river. The valley of Porsuk River is suitable to construct concrete faced rockfill dams (CFRDs). For this propose, initially, historical data of inlet and outlet of Porsuk reservoir has been investigated. Historical data have been analyzed on a monthly basis for 32 years. It has been calculated that the electricity generation using this potential is 20.69 GWh/year with 4.2 MW installed capacity from Porsuk Dam. For the evaluation of all the Porsuk River water potential, it is required constructing at least two new dams in the hilly Porsuk basin. It is calculated that the total electricity generation from these two will reach up to 37.79 GWh/year with 2×2.8 MW installed capacity.

ICA and water in Korea – overview

The natural water quality in Korea has improved significantly in the last 20 years since major collective national initiatives were implemented by governmental agencies, non-governmental organizations, and professionals among many others. Recently instrumentation, control, and automation (ICA) technology has become one of the most important technologies for carrying out this task. Korea has become especially well known with a strong reputation for information technology and international business with commercial products like semi-conductors, computers, mobile phones, computer games, and other electronic products. In this paper the background of Korean water quality is reviewed and several of the most significant national projects related to ICA are discussed. The major projects may include the Automatic Monitoring Network of River Water Quality and the Integrated Management System of Wastewater Treatment Plants in Upper Basin Area of Multi-purpose Dams.

Electricity Generation from Existing Multipurpose Dams in Turkey

The aim of this article is to investigate the hydropower potential of multipurpose dams constructed with the purpose of supplying irrigation, domestic water supply, flood control, navigation, recreation, sanitation, and wildlife conservation but not for electricity generation in Turkey. One of the functions of multipurpose dams is to produce electricity when released water from the reservoir. More than 1175 dams in various sizes and types have been constructed so far in Turkey and according to the International Commission on Large Dams (ICOLD) definition, 555 dams have already been in operation by 2005. At the present research, out of 1175 dams, 78 multipurpose dams with an installed capacity less than 20 MW still in operation can be rehabilitated as small hydropower facilities. For this purpose, existing 78 of multipurpose dams which do not generate electricity so far have been investigated. By using these existing multipurpose dams, only minor new civil works and ready-to-use turbine generator are required, which reduces the cost of electricity generation. It has been calculated that the electricity generation using this potential is 1090.89 GWh/yr with 287.83 MW installed capacity. This potential will add an important monetary value to Turkish economy.

Rainfall‐runoff models using artificial neural networks for ensemble streamflow prediction

AbstractPrevious ensemble streamflow prediction (ESP) studies in Korea reported that modelling error significantly affects the accuracy of the ESP probabilistic winter and spring (i.e. dry season) forecasts, and thus suggested that improving the existing rainfall‐runoff model, TANK, would be critical to obtaining more accurate probabilistic forecasts with ESP. This study used two types of artificial neural network (ANN), namely the single neural network (SNN) and the ensemble neural network (ENN), to provide better rainfall‐runoff simulation capability than TANK, which has been used with the ESP system for forecasting monthly inflows to the Daecheong multipurpose dam in Korea. Using the bagging method, the ENN combines the outputs of member networks so that it can control the generalization error better than an SNN. This study compares the two ANN models with TANK with respect to the relative bias and the root‐mean‐square error. The overall results showed that the ENN performed the best among the three rainfall‐runoff models. The ENN also considerably improved the probabilistic forecasting accuracy, measured in terms of average hit score, half‐Brier score and hit rate, of the present ESP system that used TANK. Therefore, this study concludes that the ENN would be more effective for ESP rainfall‐runoff modelling than TANK or an SNN. Copyright © 2005 John Wiley & Sons, Ltd.

국내무역에서의 PRMS 모형의 적용성에 관한 연구

본 연구에서는 미국 지질조사국에서 개발한 PRMS 모형을 국내 7개 댐유역에 적용하여 국내 적용성과 모의한 계를 분석하였다. 모형의 적용성을 평가하기 위해 모형 이론과 매개변수에 대해 검토하고, 국내 실정을 고려한 입력자료와 매개변수 추정의 가용성을 분석하였다. 각 적용유역들에서 GIS자료를 활용하여 추정 가능한 매개변수들은 추정하고 나머지 변수들은 Rosenbrock 방법을 이용하여 보정하였다. 모의결과를 다각적으로 분석하여 PRMS 모형의 모의 능력과 한계를 분석한 결과 PRMS 모형은 모든 적용유역에서 관측치에 높은 적합성을 나타내었다. 기본값을 사용한 융설모의에서도 비교적 정확한 모의가 가능한 것으로 나타났다. 적용 유역면적에 상관없이 신뢰성 높은 유출분석이 가능하였으나, 대유역인 경우 준분포형적인 특성보다는 일체형모형에 가까운 유출모의를 하는 것으로 나타났다. The objective of this study is to evaluate the applicability and simulation capability of PRMS, developed by U.S. Geological Survey, over the seven multi-purpose dam watersheds in Korea. The basic concepts of model components and their parameters are investigated for the evaluation of model applicability and the possibility of model parameter estimation is suggested based on the data availibility. For model parameter estimation, some parameters are directly estimated from measurable basin characteristics, but the others are estimated by Rosenbrock's automatic optimization scheme. The results show that the simulated flows from the model were very close to the observed ones. Although the default values for snowmelt model parameter are used, the results from snowmelt simulation is also acceptable. The model shows that the simulation capability is not sensitive to the basin size, however, according to increasing basin area, simulation characteristics are close to those for lumped model rather than semi-distributed model.

기포에 의한 점착성 퇴적물의 부유

The elimination and erosion of cohesive sediments in port and reservoir water can so far be processed only with mechanical evacuation methods under extreme energy expenditure. The so-called flushing jets do not serve the purpose because they cannot set the material spaciously in motion despite high shear stresses at the bed. Therefore this study aims to examine the resuspension of the deposited fine material() under presence of gas bubbles in order to decreased cohesive sediments in multipurpose dam, port and lakes. In the case of laboratory trial important parameters considered are supplied amount of air and the consolidation time of the solid materials. With increasing gas content alumina remains in suspension at high pH values in the laboratory test, where the particles fall mote rapidly without air addition.

자유경쟁 시장 내에서 용담다목적댐 발전소의 최적 계약가능 공급량 평가

요즘 다목적댐의 수력발전을 일으킬 수 있는 수자원은 용수공급이 증가함에 따라서 점점 감소하고 있는 형편이다. 한편 국내 수력 발전량의 거래가 다자간의 시장경제 체제로 형성될 경우, 수력에너지 생산자는 최적 공급량과 공급의 수문학적 신뢰도 수준을 제시해야 한다. 이에 본 연구에서는 금강 수계 내 위치한 용담다목적댐의 수력 발전소에서 공급가능한 발전량과 공급 신뢰도를 평가하기 위하여 저수지 조작 기법으로 선형계획법을 적용하였고 1차원 조사법을 이용하여 유입량의 신뢰도와 수력 발전 공급량의 최적치를 결정하였고 그 주요 결과를 제시하였다. Nowaday the amount of water resource to generate the hydro-power energy has decreased as that of the water supply has increased. In case that the national market of the energy will be in free competition, the energy producer need to suggest the amount of the optimal supply with the hydrological reliability for a deal. In this study the optimal reservoir operation was performed by the linear programming and the optimal reliabilities of inflows and the power supply were obtained by the one dimensional search technique to estimate the energy with the optimal inflow reliability which the power system of the Yongdam multipurpose dam in Geum river can produce. And the main results were presented.

Underground excavation in Xiaolangdi project in Yellow River

The paper summarizes the excavation methodology, based on analysis of the characteristics of the surrounding rock mass, which has been involved in Xiaolangdi multipurpose dam project. Some special support and excavation methods, such as twin side drift and lattice girder, moderate blasting and double-layer mesh to collapsed tunnel and fault zone, are presented.

Use of willows as countermeasure in lakefront barren areas of multipurpose dam

This paper recommends the planting of indigenous tree species as a countermeasure against formation of lakefront barren areas that are prevalent in multipurpose dam schemes nationwide.The limited water-level method adopted by multipurpose dams usually results in periodic inundations in lakefront areas during significant water-level changes, leading to harsh conditions for plant growth. However, vegetation maintenance is necessary to prevent erosion. Thus, it is recommended that specific tree species such as willows, characterized by inundation-proofconsistent growth cycle and early growth, be planted in lakefront barren areas. This countermeasure has potential to become popular if its effectiveness is verified, because it is environment-friendly and relatively cost-effective, as it employs an indigenous species of willow.The above results proved that the proposed countermeasure is cost-effective and easily implemented.

Inflow Forecasting of a Dam by Neural Network Using Rain Data in Wide Area

At a multipurpose dam, it is necessary to forecast inflow to control flood safely and to operate hydraulic power plant efficiently. In this paper, we propose a method of forecasting the inflow of several hours later by neural network. The correlation is high about the inflow and rain which fell in the dam basin, but it is difficult to forecast by mathematical methods, because the relation is non-linear model. The neural network system can forecast the inflow by learning the past data of inflow and rain in the basin. This system can forecast inflow well after 1 hour or so. However, this system becomes inaccurate rapidly when it tries to forecast inflow at 3 or more hours later, because we use the rain data of the dam basin. Therefore, we also use rain data which is out of the dam basin and in the direction of the windward. The rain data contains information of the rain which will fall at the dam in future. Then, forecast results show that our system is effective.

용수 수요를 고려한 DAWAST 모형의 적용성 평가

개념적 집중형 일 유출모형인 DAWAST모형을 선정하여 용수수요를 고려할 수 있는 가능성을 검토하였다. 기존 모형에 의한 모의 유량을 자연유량으로 보았고, 농업용수, 생활용수, 공업용수 등 회귀수량을 더한 값을 하천유량으로 가정하였다. 농업용수의 수요량은 회귀수량이 논으로부터만 발생하는 것으로 보아 논 용수량만을 고려하였으며, 수정 Penman공식에 의한 증발산량, 침투량, 재배관리수량, 유효우량 등을 고려한 일별 감수심에 의해 일별로 계산하였다. 생활용수, 공업용수 수요량은 일 평균값에 월별 변동계수를 고려하여 일별로 계산하였다. 신뢰도가 높은 대청댐 운영실적의 유입량 자료를 이용하여 용수수요를 고려한 DAWAST 모형의 적용성을 평가하였다. 농업용수의 회귀율은 35%, 생공용수의 회귀율은 65% 적용하였으며, 1983년∼2001년 연평균하여 강우량 1184.6 mm 관측 유입량 667.3 mm 모의 유입량 652.6 mm 로 용수수요를 고려하지 않은 경우의 모의 유입량 606.8 mm에 비해 45.8 mm 가 높게 나타났으며, 모의/관측 유입량 비율도 90.9 % 에서 97.8% 로 개선되는 결과를 얻었다. The DAWAST model was originally developed to consider the variation of water storage in the unsaturated soil zone and it is a conceptual lumped model. Return flows from agricultural, domestic and industrial water were included to the original result of model simulation to calibrate model parameters of watershed runoff. Agricultural water demand was estimated only in paddy fields supposing that return flow responded at stream was originated from paddy fields. Domestic and industrial water demand was estimated by average daily water demand multiplied monthly variation coefficient. Daily inflow to the Daechung multipurpose dam was applied to verify the DAWAST model considered return flows. On annual average from 1983 to 2001, inflows were simulated to 652.5 mm with return flows considered, which was approached more closer to observed inflow of 667.3 mm, compared with case of 606.8 mm with return flows not considered.

Next Generation National-Wide Hydropower Integrated Scada System

Korea Water Resources Corporation (KOWACO), the only organization specialized in water resources management in Korea, is planning to establish a centralized control system for a related operation, in the central control room, of decision making as to water management and electric power generation.This plan is intended to convert the existing on-site operation system in each multi-purpose dam across the nation into a central operation system in the Corporation's head office, for which Generation Integrated Operating System (GIOS) will be established control center in the Corporation's head office and modernized nine (9) power stations, substations (RDAC). This article discusses realization of GIOS, especially real-time operation of hydropower plants and a specific architectural features for system communication.

모의기법에 의한 홍수기 저수지 운영 모형 개발(II)

본 연구의 제Ⅰ보 (신용노 등, 2000)에서는 댐의 제약조건과 댐 상·하류의 유출상황을 고려하여 홍수기 댐을 운영 할 수 있는 모의기법 모형인 EV ROM을 개발하였고, 본 보에서는 제Ⅰ보에서 개발된 EV ROM을 FORTRAN Power Station 4.0에 의해 금강수계 댐군을 연계운영 할 수 있는 전산프로그램을 개발하였다. 개발된 프로그램을 사용하여 금강수계에서 발생한 3개 홍수사상에 적용해 본 결과 기존의 Rigid ROM이나 Technical ROM보다 효과적인 것으로 나타났다. 이는 본 연구에서 개발한 EV ROM이 댐 유역뿐만 아니라 댐 하류 홍수제어지점의 수문상황을 동시에 고려하여 댐의 방류계열을 결정하였기 때문이다. 향후, 본 연구에서 개발된 EV ROM을 다양한 홍수사상에 적용하기 위해서는 예측강우량의 정확도 개선과 함께 프로그램의 지속적인 보완이 이루어져야 할 것이다. The EV ROM, a joint reservoir operation model for flood control that accounts for the downstream flow condition, has been introduced in the preceding article (Shin et al, 2000). A joint reservoir operation model computer program for the Geum river basin, developed by FORTRAN Power Station 4.0 using the EV ROM, is hereby presented. Three case studies of flood control by joint operation of the Yongdam and Daechung Multipurpose Dams in the Geum river basin revealed that the performance of the EV ROM was superior to the existing Rigid ROM and Technical ROM. This is because the EV ROM can account for the downstream flow condition as well as the upstream inflow and the reservoir water level. In order to apply for various floods events in the future, consistent improvement of the developed EV ROM and efforts for more accurate rainfall prediction are required.