• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3C
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• pp.209-218
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• 2006

In this study, stress and deformation of CFRD during its construction and impounding were analyzed and compared with its monitoring results. Moreover, deformation characteristics of CFRD after impounding were evaluated based on the settlement monitoring records of total 23 domestic and foreign CFRDs during construction and impounding. The investigation on the behavior of CFRD indicated that the influence of impounding on its stability was minimal although slight increases in vertical and horizontal stresses and strains were observed. Also, one method was proposed to predict a crest settlement from multi-layer settlements by applying the best fit method. It is expected that the results of this study would provide practical information for the design, construction, and management of CFRD.

• Journal of the Korean Geosynthetics Society
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• v.17 no.1
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• pp.21-31
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• 2018

This paper analyzes the displacements of CFRD which was completed by field measurement. It is to understand the deformation behavior of the dam body according to the water level change from the impounding time. And it was compared with numerical analysis results. As a result of measuring the behavior of the dam crest and downstream slope according to impounding, horizontal displacements in axis direction of the dam, upstream and downstream displacements and settlements occurred mostly when the water level reaches about half of the dam height. The displacements continued until the water level reached its maximum. After that, it showed a constant convergence regardless of the water level. Horizontal displacements of the face slab which is the most important in CFRD were similar at all locations. The Horizontal displacements of the face slab showed the trends of increasing in winter and decreasing in summer due to the effect of the outside temperature before impounding. Also, the displacements increased until the water level reached about half of the dam height. After that, they decreased with rising in water level. As a result, the face slab behaviors according to seasonal change after impounding as well as water level condition. It is judged because of the material characteristics of the concrete slab. Numerical analysis showed slightly different maximum settlement and depth of occurrence from the measuring data after construction of the dam. It is considered that this is due to various design and construction differences such as the estimation of input parameters in analysis, construction period, and the layer thickness of construction. For the overall period of the dam, the settlements were mostly completed during the construction period and some settlements occurred in the early days of impounding and then converged.

• Proceedings of the Korea Water Resources Association Conference
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• 1998.05a
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• pp.68-75
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• 1998

• Magazine of the Korean Society of Agricultural Engineers
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• v.41 no.5
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• pp.53-67
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• 1999

In this study, regional frequency analysis is used to determine each subbasin drought frequency with watershed runoff which is calculated with Tank Model in Nakdong river basin. L-Monments methd which is almost unbiased and nearly normal distribution is applied to estimate paramers of drought frequency analysis of monthly runoff time series. The duration of '76-77 was the most severe drought year than othe rwater years in this study. To decide drought frequency of each subbasin from the main basin, it is calculated by interpolaing runoff from the frequency-druoght runoff relationship. and the linear regression analysis is accomplished between drought frequency of main basin and that of each subbasin. With the results of linear regression analysis, the drought runoff of each subbasin is calculated corresponing to drought frequency 10,20 and 30 years of Nakdong river basin considering safety standards for the design of impounding facilities. As the results of this study, the proposed methodology and procedure of this study can be applied to water budget analysis considering safety standards for the design of impounding facilities in the large-scale river basin. For this purpose, above all, it is recommanded that expansion of reliable observed runoff data is necessary instead of calculated runoff by rainfall-runoff conceptual model.

• Journal of Environmental Health Sciences
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• v.21 no.1
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• pp.29-38
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• 1995

The purpose of this study is to improve the present methodology-for the estimation of optimal water supply from an impounding reservoir. The stochastic reservoir storage model presented in this paper is believed to be rational in that. the probability of reservoir depletion (return period) is to be calculated for the various monthly demands and storage capacities. The monthly flows are used to derive the reservoir storage capacity-monthly demand-probability curves at Dalcheon damsite and Hongcheon damsite in Han river basin.

• Journal of the Korean GEO-environmental Society
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• v.16 no.2
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• pp.5-13
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• 2015

In the present study, the prediction methods of the crest settlement after impounding and the maximum internal settlement during dam construction were proposed through the analysis on settlement data at 38 monitored points of 36 Concrete-Faced Rockfill Dams (CFRDs). The results from this analysis provided that the crest settlement and the maximum internal settlement are increased in proportion to the dam height and the void ratio. However, the relationship between internal settlement and dam height for each void-ratio range plotted in semi-logarithmic scale is the nearly same. Also, the prediction of the crest settlement of the CFRD is possible through the maximum internal settlement during dam construction. In addition, it seems that the valley shape highly affects the dense dam body with high construction modulus. The results of this study will provide the useful tool for the design, construction and management of CFRDs.

• Journal of Ecology and Environment
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• v.43 no.1
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• pp.22-30
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• 2019

Background: Piton du Milieu (PdM) impounding reservoir is suspected to be eutrophic based on the elevated level of orthophosphate and nitrate. Water supplies from three adjacent rivers are primarily thought to contribute to the nutrient enrichment of the reservoir. It is also suspected that there is leaching of orthophosphate, nitrate and organic matter into the rivers during rainfall events and also as a result of anthropogenic activities within the catchment area. The aim of this study was to ascertain the impact of nutrient loading on the water quality of PdM water and on the population of freshwater microalgae in the reservoir. The enumeration and identification of algae from PdM were performed by differential interference contrast microscopy. Dissolved oxygen (DO) and pH were determined by electrometric methods, whereas nutrient levels, silica and total organic carbon (TOC) were determined by instrumentation techniques. Results: Annual mean orthophosphate, nitrate and total organic carbon input from the three feeders within the catchment area of PdM reached levels as high as 0.09 mg/L, 0.4 mg/L and 2.62 ppm respectively. Over a 12-month period, mean TOC concentration in the reservoir was 2.32 ppm while the mean algal cell count was 4601 cells/mL. The dominant algal species identified were Oscillatoria, Cyclotella, Navicula and Cosmarium. Conclusion: This study highlights the trophic state of the reservoir water and clearly points to the need for constant monitoring in order to avoid the occurrence of an impending harmful algal bloom.

• Journal of the Korean Society of Safety
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• v.19 no.2
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• pp.88-92
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• 2004

The paper decribes a procedure for the evaluation of the effect of seepage force on stability of slopes. The stability of an embankment impounding a water reservoir is highly depend upon the location of seepage line with the embankment. To evaluate the accurate safety factor of an embankment, it is important to illustrate the seepage phenomenon. Of particular interest is the stability following a rapid change of reservoir level. Seepage forces in embankments are easily determined interest is the stability following a rapid change of resrvoir level. Seepage forces in embankments are easily detemined if frictional forces are expressed in relation to hydraulic gradient I. If a piezometer is inserted into a body of embankment, the level to which fee water rises is a measure of the energy at that point.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.4
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• pp.73-81
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• 2012

In this study, the settlement data of 32 center cored rockfill dams (total 39 monitored data) were collected and analyzed to develop the method to predict the crest settlement of a CCRD after impounding by using the internal settlement data occurred during construction. An artificial neural network (ANN) modeling was used in developing the method, which was considered to be a more reliable approach since in the ANN model dam height, core width, and core type were all considered as input variables in deriving the crest settlement, whereas in conventional methods, such as Clements's method, only dam height is used as a variable. The ANN analysis results showed a good agreement with the measured data, compared to those by the conventional methods using regression analysis. In addition, a simple procedure to use the ANN model for engineers in practice was provided by proposing the equations used for given input values.

• Journal of the Korean Society of Safety
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• v.12 no.4
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• pp.134-142
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• 1997

The stability of an embankment Impounding a water reservoir is highly depend upon the location of seepage line with the embankment. To evaluate the accurate safety factor of an embankment, it is important to illustrate the seepage phenomenon. Of particular interest is the stability following a rapid change (drawdown) of reservoir level Seepage forces in embankments are easily determined if frictional forces are expressed in relation to hydraulic gradient Ⅰ. If a piezometer is inserted into a body of embankment, the level to which free water rises is a measure of the energy at that point. From model test result, it is possible to calculate safety factors of earth embankment. To assure the validity of this research, tests were conducted with numerical experimental models. And the experiment models were constructed with slopes of 1:1.0, 1:1.5, 1:2.0, 1:2.5. Analysis of experimental results, seepage force was analyzed according to downstream time, internal friction angle and cohesion, respectively.