• Journal of Korean Society on Water Environment
• /
• v.22 no.6
• /
• pp.1094-1100
• /
• 2006

In this study, the reservoir sediment reduction methods for long-term operation are proposed by the analysis of both sediment deposit characteristics and sediment reduction effect by each method. To that end, a flowchart for sediment analysis in reservoir is established and sediment deposit is simulated by SMS-SED2D model. The sediment reduction methods which are sediment passing (sluicing), flushing, trapping, bypassing and mechanical removal are used. From the simulation results, the effective method for sediment reduction is operation which is coupled by both sediment passing with sand gate and sediment trapping with debris dam. And If sediment flushing will be used once a year after 50 years, conservation storage can be secured until 100 years after dam construction.

• Journal of Korea Water Resources Association
• /
• v.51 no.1
• /
• pp.61-70
• /
• 2018

This study examined how to determine the optimal sediment level in dam reservoir for efficient plan and operation of dam. Currently, Korea is applying a horizontally accumulated method for sediment level estimation for the safety design of dam and so the method estimated relatively higher level than others. However, the sediment level of dam reservoir should be accurately estimated because it is an important factor in assessing life cycle of a dam. The sediment level in dam reservoir can be determined by SED-2D model linked with RMA-2, horizontally accumulated method, area increment method, and empirical area reduction method. The estimated sediment level from each method was compared with the observed sediment level measured in 2007 in Imha dam reservoir, Korea and then the optimal method was determined. Also, the future sediment level was predicted by each method for the future trend analysis of sediment level. As the results, the most accurate sediment level was estimated by the empirical area reduction method and the future trend of sediment level variation followed the past trend. Therefore, we have found that the empirical area reduction method is a proper one for more accurate estimation of sediment level and it can be validated by the results from a numerical model of SED-2D linked with RMA-2 model.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.2 no.3 s.6
• /
• pp.109-117
• /
• 2002

An analysis to allocate storage space for sediment accumulation during the economic life of the reservoir is required in the planning or design of a reservoir. This analysis has been the most difficult and tedious aspect to deal with reservoir sedimentation because of the interaction between the various parameters related to the hydraulics of flow, reservoir operating policy, inflowing sediment load. The approach to analyzing spatial distribution of deposits has relied on empirical methods, all of which required a great deal of simplification from the actual physical phenomena. For the purpose of this study, reservoir sedimentation rate computed by Empirical Area Reduction Method is compared with measuring rate along the Soyang-gang Dam. As a conclusion, reservoir sedimentation rate can be estimated exactly by Empirical Area Reduction Method.

• Journal of Korean Society on Water Environment
• /
• v.29 no.1
• /
• pp.29-35
• /
• 2013

Recently, various Best Management Practices (BMPs) have been applied at a field to reduce soil erosion. Hourly Runoff and Sediment Model for Best Management Practices (HRSM4BMP) model could be used to evaluate soil erosion reduction for various agricultural BMPs at fields. Runoff and sediment yield from source areas have to be predicted with greater accuracies to evaluate sediment reduction efficiently with BMPs. To achieve this, the best parameters related with runoff and sediment modules of the HRSM4BMP model should be identified with proper calibration processes. Although manual calibration is often utilized in calibrating runoff and sediment using the HRSM4BMP, objective calibration method would be recommended. The purpose of the study was to develop an automatic calibration tool of the HRSM4BMP model with PARASOL method. This automatic calibration tool was applied to Bangdongri, Chuncheon-si to evaluate its calibration performance. The $R^2$, NSE and RMSE value for runoff estimation were 0.92, 0.92, $0.3m^3$, and for sediment yield estimation were 0.94, 0.94, 0.0027 kg. As shown in this result, automatic calibration tool of HRSM4BMP model would be used to determine the best parameters and can be used to simulate runoff and sediment yield with acceptable accuracies.

• Progress in Superconductivity and Cryogenics
• /
• v.21 no.2
• /
• pp.31-35
• /
• 2019

Andong-dam was built up in 1967 and it is one of the biggest dams in Korea. Previous studies showed that the sediments are highly contaminated with heavy metals such as arsenic, cadmium, and lead. Many research projects are going on to find out the source of the contamination, to evaluate the toxicities to ecosystem, to estimate the volume of sediment to be treated and to find out a good remediation method. Reports show that the sediment is highly contaminated and the main contamination source is supposed to be abandoned mines and a zinc refinery located upper stream of the river. A magnetic separation has been tested as a treatment method for the dredged sediment. Lab scale test showed that the magnetically captured portion is about 10% in weight but the contamination of heavy metal is much higher than the contamination of the passed portion. This indicates that a magnetic separation could be applied for the purpose of reduction of sediment to be treated and for increasing the volume of low toxic sediments which can be dumped as general waste. A magnetic separation using a HGMS has been tested for the sediment with variable magnetic field and the results showed the higher magnetic field increase the captured portion but the concentrating effect of heavy metal was weakened. Further study is needed to establish a useful technology and optimization between decontamination and reduction of sediment volume.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.56 no.6
• /
• pp.121-128
• /
• 2014

Development of the economic methods and the design of the standard sections needs the more project fund and land than ever leads to the objection of enlarging canal arrangement to need economic construction method development and standard design for supporting it. The objective of this study was to evaluate the performance of selected sediment reduction methods to reduce sediment discharges from drain and irrigation of different land types (Mountain, Flatten, Reclaimed land). This study was carried out to analysis for the soil loss and sediment of drain and irrigation by comparing RUSLE method and amount of sediment from amount of dredging data of Korea Rural Corporation. The results of study were analyzed and summarized as follow. Size of soil sediment from the upper region of drain and irrigation of mountains bigger than lower region. But in case of flatten and reclaimed land, size of soil sediment from the upper and lower region of drain and irrigation did not classified. In case of comparison drain and irrigation without classifying of land type, size of soil sediment from irrigation is bigger than drain.

• Journal of Korea Water Resources Association
• /
• v.44 no.1
• /
• pp.31-40
• /
• 2011

In this study, the methods of sedimentation reduction for the estuary barrage were analyzed using the CCHE2D bed change model. Especially, the effectiveness of sediment dredging currently applied in the field was evaluated quantitatively and also the channel contraction method which is a substitute method was analyzed for the Nakdong River Estuary Barrage (NREB). The numerical model was calibrated and validated for the sediment transport equations and transport modes. In the NREB case, the Ackers and White formula and bed load type was the most similar to the field condition. As a results of the dredging simulation, there was the sedimentation reduction effect of 0.2 m in the bed changes. Furthermore, the analysis result of the channel contraction method represented that the sedimentation reduction effects of the average 0.4 m and the maximum 2.0 m were produced.

• Water Engineering Research
• /
• v.4 no.2
• /
• pp.99-109
• /
• 2003

Since bed elevation changes are mainly dependent on the flow velocity and corresponding shear stress, it is possible to predict bed elevation numerically using velocity components. For the scour analysis due to channel contraction, a bed load transport model is developed and applied to estimate scour depth around coffer dam in the Mississippi River. During Phase I of the Lock & Dam No. 26 replacement project, a coffer dam was constructed to reduce the flow area approximately by 50%. Flow velocity increases due to the flow area reduction yields significant lowering (erosion) of the channel bed elevation. The proposed numerical model solves the sediment continuity equation using the finite element method to evaluate scour process in the vicinity of the coffer dam

• Journal of Digital Convergence
• /
• v.16 no.7
• /
• pp.47-54
• /
• 2018

Sediment disaster happen frequently in our country every year, and a lot of lives and the properties have been lost because of them. Non-structural measures for prevention of sediment disaster have been introduced by prefectures based on the Sediment-related Disaster Prevention Law established after the devastating rainstorm damage in Hiroshima in 1999. They include formulation of sediment disaster warning and evacuation standard rainfall and designation of sediment disaster warning zones and sediment disaster special warning zones. As a practical example, this research focused on the case of "TEC-FORCE" of "MLIT of Japan" as a method of utilizing professional workforce and the sediment disaster warning information delivery system in Kagoshima. In the future, it will be called for prevention and reduction of damages by utilizing professional workforce and sediment disaster response system such as Japan.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.55 no.5
• /
• pp.1-7
• /
• 2013

The objective of this research was to experimentally test the effect of tillage methods on the reduction of runoff, non-point source (NPS) pollution load, sediment and discharge under a rainfall simulation. We used the runoff plots of $5m{\times}30m$ ($L{\times}W$) in size. Experimental treatments were conventional tillage (CT), CT-rice straw bundle (CT-RSB) and two no-till (NT) plots; slope of 3 % or 8 % ; and rainfall intensity of 30 mm/hr. The rainfall simulation was conducted to three times. The time to initial runoff from NT plots was less than that from CT plots regardless of the slope and it was delayed about 65~90 % compared to that of CT plot. And sediment discharge of 8 % slope reduced to 55 % compared to CT plot. But the sediment discharge was not occurred at 3 % slope. The NT and CT-RSB methods have a great possibility of reducing runoff and NPS pollution loads. Runoff rate of NT plots was significantly lower than those of CT plot. The average NPS pollution loads of the NT plots and CT-RSB plot reduced about 55~80 % and 2.1~40 % compared to those of the CT plots, respectively. It was also shown that runoff and NPS pollution loads reduction by NT method could be very significant and contribute to improve the water quality of streams in agricultural regions. It was concluded that the use of NT method on agricultural fields could reduce soil erosion and muddy runoff significantly and help improve the water quality and aquatic ecosystem.