• Geomechanics and Engineering
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• v.10 no.6
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• pp.727-736
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• 2016

Excessive rainfall can cause runoff flows over the soil surface and as a consequence some amount of water will infiltrate into the soil. From a hydrologic modeling perspective it is necessary to estimate infiltration rate in order to calculate the actual runoff discharge. There are many parameters that can affect the infiltration rate such as soil texture, moisture and compaction. However, the most common equations used in hydrological calculations for estimating the infiltration rate do not consider the soil properties directly and estimate infiltration rate without any soil properties expressions. The purpose of this research was to investigate the relations between infiltration rate and soil texture, moisture and compaction. To achieve this purpose an experimental study was performed to show the effect of soil properties and their relations on infiltration rate by using non-linear regression.

• Journal of Wetlands Research
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• v.13 no.3
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• pp.465-470
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• 2011

Liquid fertilizer and composted cattle manure were applied to an agricultural land. This study was conducted to find the pathway of the nutrients transport. Nitrogen concentration was decreased by the repeatable precipitation in surface runoff, but the nitrate concentration in ground water was gradually increased by biological metabolism, especially with pig liquid fertilizer. Phosphorus was mostly adsorbed into the soil, and its reduction was affected by the soil drain by surface runoff in the summer. Averaged adsorption capacity of the phosphorus via Jar-test was determined as 21.5 mg P/kg of soil.

• Magazine of the Korean Society of Agricultural Engineers
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• v.37 no.5
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• pp.81-89
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• 1995

One of the most difficult problem to estimate the flood inflow is how to understand the effective rainfall. The effective rainfall is absolutely influenced by the condition of soil moisture in the watershed just before the storm event. DAWAST model developed to simulate the daily streamflow considering the meteologic and geographic characteristics in the Korean watersheds was applied to understand the soil moisture and estimate the effective rainfall rather accurately through the daily water balance in the watershed. From this soil moisture and effective rainfall, concentration time, dimensionless hydrograph, and addition of baseflow, the rainfall-runoff model for flood flow was developed by converting the concept of long-term runoff into short-term runoff. And, real-time flood forecasting model was also developed to forecast the flood-inflow hydrograph to the river and reservoir, and called RETFLO model. According to the model verification, RETFLO model can be practically applied to the medium and small river and reservoir to forecast the flood hydrograph with peak discharge, peak time, and volume. Consequently, flood forecasting and warning system in the river and the reservoir can be greatly improved by using personal computer.

• Journal of Environmental Impact Assessment
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• v.22 no.1
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• pp.1-17
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• 2013

Carbon sequestration on soil is one of the counter measurements against climate change in agricultural sector. Increasing incorporation of organic fertilizer would increase soil organic carbon (SOC) but it could bring high potential of nutrient losses which would result in water quality degradation. In this paper, literature review on soil organic carbon behavior according to agricultural management is presented. The results of field experiment to identify the effect of organic and commercial fertilizer applications on SOC and runoff water quality were also presented. Field experiment confirmed increased SOC and nutrient concentrations in runoff water as application rate of organic fertilizer increase. The potential use of simulation model to develop best agricultural management practice considering carbon sequestration and water quality conservation at the same time is discussed and monitoring and modeling strategies are also suggested to achieve the goal.

• Journal of Korea Spatial Information System Society
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• v.11 no.1
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• pp.97-104
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• 2009

GIS (Geographic Information System) is very useful in describing basin wide geographic characteristics and hydrologic analysis. This study estimated long term hydrologic variations in the Geum river basin using the SSARR rainfall runoff simulation model to provide reliable hydrologic information associated with rainfall runoff management module. Calibrated various hydrologic information such as soil moisture index, water use, direct and base flow are generated using GIS tools to display spatial hydrologic information in the unit of subbasin of target watershed. In addition, the graphic user interface toolkit designed for data compilation is expected to support efficient basin wide rainfall runoff analysis.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.48-58
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• 2004

Objectives of this research were to reclaim the coal mine overburdens using the lime waste cake from the soda ash production by stabilizing the overburden slopes, introducing neutralizing the AMD from runoff and leachate in an attempt find the sink to dispose the lime wastes and alleviate the environmental problems caused by the closed coal mines. The pH changes of the runoff and leachate collected in the tanks at the end of the experimental plots, averaged over measurements from April to August, indicated that the runoff pH of the coal overburden was 4.3 but increased significantly to the ranges of 6.7 to 7.1 with treatments of tile calcites and lime wastes. This might be related with the decreases in Fe concentrations in the runoff and leachate from the coal overburdens. The Fe concentrations in tile runoff seemed to increase with the amounts of precipitation. Results demonstrated that the amounts of lime wastes at 25% of the lime requirement were sufficient for neutralizing the acidic coal overburden. Either layering between the coal waste and topsoil or mixing with coal overburdens could be adopted as the lime waste treatment method. The lime wastes from the soda ash production might have a potential to be recycled for the reclamation of the abandoned coal mines to alleviate the environmental problems associated with coal mine waste.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.3
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• pp.158-164
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• 2001

The purpose of this study was to assess the runoff of nitrogen derived from pig manure under upland condition. Bare and maize cultivated conditions were compared to estimate the effect of plant on the runoff loss of nitrogen and other nutrients by application of pig manure. Soil used in this experiment was sandy loam, and the fermented pig manure was applied at the rate of 0, 50, and $100ton\;ha^{-1}$. The amount of runoff was measured after every rainfall and water samples were analyzed for nitrate and other cations. Runoff was increased with the rainfall, but was depended on the application rate of pig manure at both bare and maize cultivated plots. Concentrations of nitrate in runoff at 0, 50 and $100ton\;ha^{-1}$ application of pig manure were higher at the maize cultivated plots than those at bare plots by 86.9, 42.9, and 33.6%, respectively. However, total mass of nitrate by runoff loss was higher at the bare plot ranging from 1.34 to $3.15kg\;NO_3-N\;ha^{-1}$. The equivalent ratio of nitrate to sum of cations in runoff was higher at the bare plot than that of maize cultivated plots. The concentration of cations in runoff was in the order of K> Mg> Na> Ca.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.2-11
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• 2006

In the processes of hydrological cycle, when precipitation reaches the ground surface, water may become surface runoff or infiltrate into soil and then possibly further percolate into groundwater aquifer. A part of the water is returned to the atmosphere through evaporation and transpiration. Soil moisture dynamics driven climate fluctuations plays a key role in the simulation of water transfer among ground surface, unsaturated zone and aquifer. In this study, a one-layer canopy and a four-layer soil representation is used for a coupled soil-vegetation modeling scheme. A non-zero hydraulic diffusivity between the deepest soil layer modeled and groundwater table is used to couple the numerical equations of soil moisture and groundwater dynamics. Simulation of runoff generation is based on the mechanism of both infiltration excess overland flow and saturation overland flow nested in a numerical model of soil moisture dynamics. Thus, a comprehensive hydrological model integrating canopy, soil zone and aquifer has been developed to evaluate water resources in the plain region of Huaihe River basin in East China and simulate water transfer among precipitation, surface water, soil moisture and groundwater. The newly developed model is capable of calculating hydrological components of surface runoff, evapotranpiration from soil and aquifer, and groundwater recharge from precipitation and discharge into rivers. Regional parameterization is made by using two approaches. One is to determine most parameters representing specific physical values on the basis of characterization of soil properties in unsaturated zone and aquifer, and vegetations. The other is to calibrate the remaining few parameters on the basis of comparison between measured and simulated streamflow and groundwater tables. The integrated modeling system was successfully used in the Linhuanji catchment of Huaihe plain region. Study results demonstrate that (1) on the average 14.2% of precipitation becomes surface runoff and baseflow during a ten-year period from 1986 to 1995 and this figure fluctuates between only 3.0% in drought years of 1986, 1988, 1993 and 1994 to 24.0% in wet year of 1991; (2) groundwater directly deriving from precipitation recharge is about 15.0% t of the precipitation amount, and (3) about half of the groundwater recharge flows into rivers and loses through evaporation.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.6
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• pp.488-494
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• 2007

Highland regions for farming are generally located in slopes higher than 7%, where alpine farming systems rely on highly input agriculture management with great amounts of chemical fertilizer and/or compost. Most of the uplands is thus needed to maintain environmentally friendly soil management due to its impact on soil erosion and runoff during heavy rainfall season. Therefore, the objective of this research is to evaluate the effect of reduction of soil erosion by applying four wild edible greens (fatsia, goat beard, leopard plant, and aster). The lysimeter experiment of slope gradients of 15, 30, and 45% was conducted in an alpine region of Hoengkye, Kangwon, in 2005 and 2006. In 2005, both amounts of soil loss from the experiment plots cultivated with goat beard and aster were lower than one with Chinese cabbage by about 50%. The amounts of runoff of goat beard and aster plots were also lower than those of the others. An increase in the slope gradients was accompanied with an increase in runoff. Of the plots of slope gradient of 15, 30, and 45%, S of goat beard plots was 52.50, 108.33, and 171.50 kg, respectively. Soil loss of Chinese cabbage was 2 to 3 times as high as those of goat beard plots. These results suggest that goat beard and aster plants with minimum tillage reduce soil erosion compared to Chinese cabbage cultivation.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.22-27
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• 1998

A grid-based soil moisture routing model(GRISMORM) was developed to assess the information of groundwater recharge using spatial data such as Landsat TM and digital elevation model etc.. The model predicts the hydrologic components, that is, surface runoff, subsurface runoff, baseflow and evapotranspiration at each grid elements by grid-based water balance computation.