• Korean Journal of Soil Science and Fertilizer
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• v.40 no.2
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• pp.131-135
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• 2007

This study was performed as an effort to reduce soil loss by investigating the phase of water flow according to soil texture and rainfall pattern and by determining the canopy cover subfactor in the RUSLE (revised universal soil loss equation). Red pepper was planted at the 15% sloped lysimeter of $2m{\times}5m{\times}0.5m$ ($width{\times}length{\times}depth$) with three different textured soils (loam, clay loam and sandy loam) and the relationship between amount and intensity of rainfall; soil loss and the amount of runoff; and amount of rainfall and runoff at different soil texture were measured at the experiment station of the National Institute of Agricultural Science and Technology (NIAST) during May to October of 2005. The amount of runoff increased with increasing amount of rainfall, showing difference in the relative increase rate of runoff at different soil texture. The increase rate of runoff with unit increase of rainfall for the lysimeter with red pepper was 0.44, 0.41 and 0.13 for loam, clayey loam and sandy loam, respectively. The minimum amount of rainfall for runoff was 23.53 mm for sandy loam, 10.35 mm for loam and 5.46 mm for clayey loam, respectively. The canopy cover subfactors of red pepper were 0.425, 0.459, and 0.478 for sandy loam, loam and clayey loam, respectively.

• Journal of Environmental Science International
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• v.11 no.7
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• pp.621-626
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• 2002

Depth-area-duration(DAD) relations are important to hydrological plans and designs for the water resources as well as the flood defence. And these relations have been still in analysis and use today because they can be applied to readily available data. In this paper, rational and consistent DAD models were developed using the multiple regression analysis and basic relationships of area ratio-runoff volume about heavy rainfall occurring in the Im-Jin river basin, 1999. In addition, revised DAD models and curves that can convert a maximum point rainfall to mean area rainfall were developed and evaluated. As results, these models seem to have predictive value in order to plan and design hydrological structures of flood defence in the Im-Jin river basin.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.3
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• pp.146-156
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• 2002

The objective of this study was to develop a modified CREAMS model for paddy field conditions. The model simulates daily balance of water and nutrient from irrigated paddies using meteorological, irrigation, and agricultural management data. The model simulates daily evapotranspiration of paddy using Penman equation and determines daily flooding depth changes. Total nitrogen and phosphorus concentrations within flooding water, surface runoff, and leaching water from a paddy field also can be simulated. Parameters of the model were calibrated using observed data of the Agricultural Experiment Station of the Seoul National University in Suwon Korea. The model was applied for the irrigation period of paddy field in Gicheon area when 1,234 mm annual rainfall was occurred. The simulated losses of the total nitrogen and total phosphorous were 11.27 kg/ha and 0.98 kg/ha, respectively. There was a good agreement between observed and simulated data. It was found that CREAMS-PADDY model was capable of predicting runoff and nutrient losses from irrigated paddy fields.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.4
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• pp.377-386
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• 2010

To identify operating parameters of the up-flow filtering system, which is available to discharge filtering residue after the rain, developed for treatment of urban storm runoff, lab scale test was carried out. Removal efficiency of SS was 68.7%, 62.2%, and 58.6% at the area roading rate of 2.46m/h, 4.68m/h, and 10m/h, respectively, filtering device is desirable to operate at the lower than 4.68m/h of area roading rate to get higher level of 60% SS removal efficiency. The removal efficiency of SS was 57.1% ~ 68.7% at the raw water SS of 100mg/L ~ 600mg/L, and the SS in treated water was maintained at the constant level through the elapsed time. It is indicate that filtering device can guarantee a certain level of effluent water quality at various raw water quality. The removal efficiency of SS to the depth of filter media was 68.3%, 78.6% at the filter depth of 10 cm, 20cm respectively. The final treated water quality was showed 30.2mg/L of CODMn, 1.60mg/L of TN and 0.25mg/L of TP. The average removal efficiencies by filtering device developed in this research were recorded slightly lower levels than other research. The main reason of these results were the first, the filter depth of the media used in this test was shallow, the second, the kind of filter media in discharge port of residue. More research to kind of filter media, filter packing rate, select of media for residue discharge port should be go on to produce optimum operating condition. The result of this study would be valuable for the application of filtration device to control of urban storm water.

• Water for future
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• v.28 no.3
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• pp.175-186
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• 1995

Characteristics of runoff and groundwater qualities from a pasture and field were investigated. Flumes and monitoring wells were installed and water qualities of $NO_3$-N, TP and TKN were monitored from Aug. 1993 to Aug. 1994. Runoff from the pasture which was a sandy soil with cobbles mostly formed with seeping water at the bottom of it. But once overland flow occurred because of heavy rainfall, runoff increased sharply. $NO_3$-N concentration in pasture runoff was relatively stable ranging between 0.241-3.962mg/l. TP and TKN concentrations were stable but sharply increased once overland flow occurred. $NO_3$-N concentration in pasture groundwater was relatively stable regardless of depth of monitoring wells but TP and TKN concentrations were smaller in deeper wells. Runoff from the field which was flat and covered well with Sudan grass and surface residue was relatively small and $NO_3$-N, TP and TKN concentrations in runoff were stable and seemed unaffected by flow rate. $NO_3$-N concentration in field groundwater increased at the rate of 2.2mg/l per 100 m during a growing season as groundwater flows through the field. No significant differences in TP and TKN concentrations between the upper and lower areas in field groundwater were detected.

• Journal of Korea Water Resources Association
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• v.39 no.3 s.164
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• pp.261-274
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• 2006

This study performs a daily long-term runoff analysis for 30 years to forecast medium- and long-term probabilistic reservoir inflows on the Soyang River basin. Snowmelt is computed by Anderson's temperature index snowmelt model and potenetial evaporation is estimated by Penman-combination method to produce input data for a rainfall-runoff model. A semi-distributed TOPMODEL which is composed of hydrologic rainfall-runoff process on the headwater-catchment scale based on the original TOPMODEL and a hydraulic flow routing model to route the catchment outflows using by kinematic wave scheme is used in this study It can be observed that the time variations of the computed snowmelt and potential evaporation are well agreed with indirect observed data such as maximum snow depth and small pan evaporation. Model parameters are calibrated with low-flow(1979), medium-flow(1999), and high-flow(1990) rainfall-runoff events. In the model evaluation, relative volumetric error and correlation coefficient between observed and computed flows are computed to 5.64% and 0.91, respectively. Also, the relative volumetric errors decrease to 17% and 4% during March and April with or without the snowmelt model. It is concluded that the semi-distributed TOPMODEL has well performance and the snowmelt effects for the long-term runoff computation are important on the study area.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.35 no.4
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• pp.126-133
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• 2017

This study analyzed hydrological changes of stormwater runoff of Seolleung Jeongneung zone according to the application of LID system based on landscape Architectural technology. The results are as follows. First, when flooding occurred in Gwanghwamun in July 27, 2011, the maximum instantaneous rainfall amount was 183 mm/hr recorded at 10:00 on 27th for 10 minutes, and it was confirmed that rainfall intensity more than three times as high as the maximum rainfall of 57.5 mm/hr. Second, it is possible to control peak flow rate in the case of 1,500mm of soil thickness, so that it is possible to improve the vulnerability of flood damage in Seolleung and Jeongneung zone when applying the LID system. Third, in the berm height scenario, peak flow rate control was not controled in all depth level models, but the first stormwater runoff was delayed by 4 hours and 10 minutes compared to the soil thickness scenario. It was interpreted as a relatively important indicator the soil thickness for the initial stromwater runoff reduction and the berm height for the peak runoff. Through this, the systematic adaptation of landscape-friendly ecological factors within the cultural property protection zone could theoretically confirm the effects of flood disaster prevention.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.4
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• pp.859-866
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• 1994

It is difficult to make an exact estimate of the peak discharge or the runoff depth of flood and establish the proper measure for the flood protection since the water stage or discharge has been nearly measured at most medium or small river basins. The objective of this study is to estimate parameters of the discrete, linear, input-output model for medium or small river basin. The On-Cheon River basin in Pusan was selected for the study area. The runoff data used in the study has been observed since June 1993, and the effective rainfall was determined using the storage function method. The parameter sets of the discrete, linear, input-output model were estimated using the least squares method and the correlation function method, respectively. The calculated hydrographs by the discrete, linear, input-output model regenerated the observed outflow hydrographs well, and also the simulated flood hydrograph was comparable to the observed one. Therefore, it is believed that the discrete, linear, input-output model is simpler than other runoff analysis methods, and can be applied to a medium or small river basin.

• Journal of Korea Water Resources Association
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• v.40 no.1 s.174
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• pp.25-38
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• 2007

A grid-based urban surface runoff model for simulating the temporal variation and spatial distribution of overland flow in a drainage area was developed. The process of routing of overland flow is modeled by the nonlinear storage equation which is composed of the continuity equation and the Manning's equation. For model operation, the drainage area is divided into grid areas, and spatially distributed topographical and hydrological information for model inputs is provided. Then overland flow is routed for each of the discretized cells of the area. In order to test the applicability of this model, temporal variations and spatial distributions of flow depth and overland flow was simulated in a fictitious and a real urbanized Kunja drainage area. Results indicate that the model can simulate reasonably well the urban runoff hydrograph.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.2
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• pp.59-63
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• 2008

The surface runoff is one of the important components for the surface water balance. However, most Land Surface Models(LSMs), coupled to climate models at a large scale for the prediction and prevention of disasters caused by climate changes, simplistically estimate surface runoff from the soil water budget. Ignoring the role of surface flow depth on the infiltration rate causes errors in both surface and subsurface flow calculations. Therefore, for the comprehensive terrestrial water and energy cycle predictions in LSMs, a conjunctive surface-subsurface flow model at a large scale is developed by coupling a 1-D diffusion wave model for surface flow with the 3-D Volume Averaged Soil-moisture Transport(VAST) model for subsurface flow. This paper describes the new conjunctive surface-subsurface flow formulation developed for improvement of the prediction of surface runoff and spatial distribution of soil water by topography, along with basic schemes related to the terrestrial hydrologic system in Common Land Model(CLM), one of the state-of-the-art LSMs.