• Journal of Ocean Engineering and Technology
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• v.31 no.6
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• pp.388-396
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• 2017

A Lagrangian approach based computational fluid dynamics (CFD) was used to simulate large and/or sharp deformations and fragmentations of interfaces, including free surfaces, through tracing each particle with physical quantities. According to the concept of the particle-based CFD method, it is possible to apply it to both fluid particles and solid particles such as sand, gravel, and rock. However, the presence of more than two different phases in the same domain can make it complicated to calculate the interaction between different phases. In order to solve multiphase problems, particle interaction models for multiphase problems, including surface tension, buoyancy-correction, and interface boundary condition models, were newly adopted into the moving particle semi-implicit (MPS) method. The newly developed MPS method was used to simulate a typical validation problem involving dam breaking. Because the soil and other particles, excluding the water, may have different viscosities, various viscosity coefficients were applied in the simulations for validation. The newly developed and validated MPS method was used to simulate the mobile beds induced by broken dam flows. The effects of the viscosity on soil particles were also investigated.

• Korean Journal of Agricultural Science
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• v.37 no.2
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• pp.217-222
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• 2010

This study was conducted to investigate the effect of fertilizer composted of dam suspended particle sawdust and sewage sludge to soil properties and seedling growth. The Betula platyphylla var japonica, Zelkova serrata and Chamaecyparis obtusa were used for this study. The soil organic matter, total nitrogen, phosphorous, exchangeable calcium, magnesium, and potassium were increased with fertilizer treatment. Heavy metal concentration in soil was increased with fertilizer treatment, but the level was very low. With fertilizer treatment, growth, photosynthetic capacity, and chlorophyll concentration of seedling were improved.

• Journal of Soil and Groundwater Environment
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• v.18 no.3
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• pp.11-22
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• 2013

SEAWAT, a linked modeling program of Visual MODFLOW was used to analyze the change in groundwater levels and salinity related groundwater dam construction in Cheongsan island, Wando-Gun, Jeollanam-Do. The steady-state model results show the groundwater flow and salinity distribution of the studied area. The groundwater flows from north-west and south-east highlands into the river, located in the middle part of the basin, and is eventually discharged to the ocean. Part of the sea water infiltrates into the river; and through the estuary's alluvium aquifer, the sea water intrusion takes place spreading to about 830 m from the ocean. The transient model results show that after the groundwater dam construction, groundwater levels will rise to a maximum of 2.0 m upstream, and the groundwater storage will increase 21,000 after 10 years. Meanwhile 31% of the total area affected by sea water intrusion will decrease. To conclude, the groundwater dam is a very useful method for a secure water resource in preparation for drought and water shortages in the island regions.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.205-205
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• 2021

Surface soil moisture, which governs the partitioning of precipitation into infiltration and runoff, plays an important role in the hydrological cycle. The assimilation of satellite soil moisture retrievals into a land surface model or hydrological model has been shown to improve the predictive skill of hydrological variables. This study aims to improve streamflow prediction with Weather Research and Forecasting model-Hydrological modeling system (WRF-Hydro) by assimilating Soil Moisture Active and Passive (SMAP) data at 3 km and analyze its impacts on hydrological components. We applied Cumulative Distribution Function (CDF) technique to remove the bias of SMAP data and assimilate SMAP data (April to July 2015-2019) into WRF-Hydro by using an Ensemble Kalman Filter (EnKF) with a total 12 ensembles. Daily inflow and soil moisture estimates of major dams (Soyanggang, Chungju, Sumjin dam) of South Korea were evaluated. We investigated how hydrologic variables such as runoff, evaporation and soil moisture were better simulated with the data assimilation than without the data assimilation. The result shows that the correlation coefficient of topsoil moisture can be improved, however a change of dam inflow was not outstanding. It may attribute to the fact that soil moisture memory and the respective memory of runoff play on different time scales. These findings demonstrate that the assimilation of satellite soil moisture retrievals can improve the predictive skill of hydrological variables for a better understanding of the water cycle.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.61-68
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• 2006

Cemented Sand and Gravel(CSG) is a material made by simple mixing of rock-based raw materials such as excavated soil and riverbed gravel together with cement and water. The use of CSG methodl for cofferdam and large dam is gradually increasing in Japan because a quarry and aggregate plants can be diminished. Also, the CSG method can reduce dam construction cost, construction duration and destruction of environment. In this paper, field test and test construction of CSG method was conducted on Hwabuk Dam. The mechanical properties of CSG, such as compressive strength, extention strength and field permeability test were investigated. From the results of the experimental study, application study of CSG method was discussed.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.26-43
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• 2010

To determine the effect of draining for the drainage layer in CFGD(Concrete Faced Gravel Dam) body, centrifuge model tests were performed. Also, soil compaction works are essential to construction of dams in order to avoid unexpected settlement of superstructures. Taking advantage of oscillating accelerometer, this research was made to complement existing methods for assessment of soil stiffness. In order to examine the validity of compaction-degree suggested in the study, tests on vibration characteristics using accelerometers was also performed.

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.4
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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.

• Magazine of the Korean Society of Agricultural Engineers
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• v.12 no.4
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• pp.2090-2123
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• 1970

This paper is a report on the research of experimental model test of Andong Fill Dam, which has been planned by the Government of Korea as a project, of its over-flowing capacity in spillway, creation of minus pressure and structure of anti-water impulse in over-flow weir. Andong Fill Dam is one of the project of master development plant for water resources, locating at Nakdong River side of Korea, and is aimed to have a multi-purpose dam for flood-control, irrigation, water power, urban and industrial water supply. This dam is planned to erect in fill-dam type due to the improper soil foundation and condition for concrete dam. The refore for the proper and advantageous points, this is designed as center core fill dam. By a model minimized of Andong Fill Dam, held an experimental model test on water quentity of reservir, discharges of overflow part, low pressure and anti-water impulse of overflow part, which was conducted an experiment by flowing aspects through each section of spillway to find the changes of water pressure and that of water level, and corrected the section of each part in order to conduct a check on the creation of minus pressure not to be over acted to the allowable bundary of the section structure; and for the prevention of concentated scouring at the down stream side of flow.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1999.04a
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• pp.71-72
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• 1999

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.836-841
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• 2008

CFRD (Concrete Faced Rockfill Dam) has been world-widely constructed due to a lot of advantages compared with rockfill dam and recently, sand/gravel materials, instead of crushed rock materials, are also utilized as a main rockfill material to overcome geological and environmental problems. In this paper, the process of water infiltration into the originally unsaturated sand/gravel-fill dam is studied using two-dimensional saturated-unsaturated seepage theory. According to the results of seepage analysis, if the effective drainage zone is installed in the dam, the reservoir water infiltrate into the dam along a downward flow path towards the lower drainage area. The main body constructed with sand/gravel materials, therefore, remains unsaturated.