• Korean Journal of Soil Science and Fertilizer
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• v.42 no.spc
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• pp.47-50
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• 2009

Nutrient losses, especially nitrogen and phosphorus, in agricultural runoff can contaminate surface and ground water, leading to eutrophication. Thus, erosion control is crucial to minimizing nutrient losses from agricultural land. Assessments of various erosion control practices were carried out under various cropping system, soil management practices, and slope conditions by means of a lysimeter study and under artificial rainfall. Soil and nutrient losses were monitored in a small agricultural field to evaluate the soil conservation practices. Nutrient losses occur in runoff and leachate (dissolved nutrient) and in sediments (particulate nutrient). Dissolved nitrates accounted for the majority (about 90%) of nitrate transport within the soil. Particulate phosphate in sediments represented the majority (60% to 67%) of phosphate transport. Recently, engineering and agronomic erosion-control practices haver been used to reduce erosion problems in fields on slopes. These practices reduced soil loss, runoff, and nutrient loss to 1/6, 1/2,and 1/3 their original levels, respectively. Bioavailable particulate phosphate in sediments represents a variable but longterm source of phosphate for algae. Dissolved nitrate and phosphate are immediately available for algal uptake, so reducing fluxes of these nutrients should also reduce the risk of eutrophication.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.605-609
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• 2005

This study is to perform the rainfall-runoff analysis of the basin of Yongdam dam where is loacted in the Geumriver basin. The model used is the SAC-SMA model which was developed by U.S. National Weather Service. The Precipitation data used as the input data of the model are daily ones observed in 2002 and the mean of values recorded in 5 rainfall stations. The evaporation data are used observed in Daejeon meteorological station. The geographical data such as basin slope and stream gradient are elicited from the numerical map analysis. In the verification through the comparison of calculated daily inflow with observed one, parameters used in the model are estimated manually. As the result of verification, total annual calculated inflow is 13,547CMS and agree accurately with the observed one. During the period of one year of 2002, before 100 days and after 250 days, the soil moisture condition in the upper zone was significantly dry and in spite of the rainfall in this period, the runoff was not generated. Through this result, we can observe that the moisture condition in the soil affects strongly the runoff in a basin.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.363-373
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• 2010

"Curve number" (CN) indicates the runoff potential of an area. The US Soil Conservation Service (SCS)'s CN method is a simple, widely used, and efficient method for estimating the runoff from a rainfall event in a particular area, especially in ungauged basins. The use of soil maps requested from end-users was dominant up to about 80% of total use for estimating CN based rainfall-runoff. This study introduce the use of soil maps with respect to hydrologic and watershed management focused on hydrologic soil group and a case study resulted in assessing effective rainfall and runoff hydrograph based on SCS-CN method in a small watershed. The ratio of distribution areas for hydrologic soil group based on detailed soil map (1:25,000) of Korea were 42.2% (A), 29.4% (B), 18.5% (C), and 9.9% (D) for HSG 1995, and 35.1% (A), 15.7% (B), 5.5% (C), and 43.7% (D) for HSG 2006, respectively. The ratio of D group in HSG 2006 accounted for 43.7% of the total and 34.1% reclassified from A, B, and C groups of HSG 1995. Similarity between HSG 1995 and 2006 was about 55%. Our study area was located in Sosu-myeon, Goesan-gun including an approx. 44 $km^2$-catchment, Chungchungbuk-do. We used a digital elevation model (DEM) to delineate the catchments. The soils were classified into 4 hydrologic soil groups on the basis of measured infiltration rate and a model of the representative soils of the study area reported by Jung et al. 2006. Digital soil maps (1:5,000) were used for classifying hydrologic soil groups on the basis of soil series unit. Using high resolution satellite images, we delineated the boundary of each field or other parcel on computer screen, then surveyed the land use and cover in each. We calculated CN for each and used those data and a land use and cover map and a hydrologic soil map to estimate runoff. CN values, which are ranged from 0 (no runoff) to 100 (all precipitation runs off), of the catchment were 73 by HSG 1995 and 79 by HSG 2006, respectively. Each runoff response, peak runoff and time-to-peak, was examined using the SCS triangular synthetic unit hydrograph, and the results of HSG 2006 showed better agreement with the field observed data than those with use of HSG 1995.

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.4
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• pp.9-19
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• 2016

The objective of this study was to evaluate the applicability of SWAT (Soil and Water Assessment Tool) model for runoff estimation in the Nam river dam watershed. Input data for the SWAT model were established using spatial data (land use, soil, digital elevation map) and weather data. The SWAT model was calibrated and validated using observed runoff data from 2003 to 2014 for three stations (Sancheong, Shinan, Changchon) within the study watershed. The $R^2$ (Determination Coefficient), RMSE (Root Mean Square Error), NSE (Nash-Sutcliffe efficiency coefficient), and RMAE (Relative Mean Absolute Error) were used to evaluate the model performance. Parameters for runoff calibration were selected based on user's manual and references and trial and error method was applied for parameter calibration. Calibration results showed that annual mean runoff were within ${\pm}5%$ error compared to observed. $R^2$ were ranged 0.64 ~ 0.75, RMSE were 2.51 ~ 4.97 mm/day, NSE were 0.48 ~ 0.65, and RMAE were 0.34 ~ 0.63 mm/day for daily runoff, respectively. The runoff comparison for three stations showed that annual runoff was higher in Changchon especially summer and winter seasons. The flow exceedance graph showed that Sancheong and Shinan stations were similar while Changchon was higher in entire fraction.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.5
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• pp.268-273
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• 2006

Soil loss induced by erosion has come to be a serious problem in Korea's sloped land since more than 70% of upland fields are located on the sloped land area. The purpose of this study was to investigate the phase of water flow in differently soil textured plot soil types by rainfall amount. Lysimeters with slope of 15%, 5 m in length, 2 m in width, and 1 m in depth were prepared and filled up with three different soil textures, such as sandy loam, loam, and clay loam, then relationships between seasonal rainfall and runoff, percolation were analyzed. Runoff and percolation rate were shown to increase linearly with increasing rainfall intensity in all the soil textures, but the starting threshold and increment rate in runoff and percolation occurrence were dependent differently upon soil textures. Percolation increment rate according to the increasing rainfall amount was 0.52, 0.36, and 0.57 for sandy loam, loam and clay loam soil respectively. The threshold rainfall amounts in which percolation occurs were 5.73 mm, 6.80 mm, and 12.86 mm for sandy loam, loam and clay loam respectively. Runoff increment rates were 0.42, 0.48 and 0.46 for sandy loam, loam and clay loam soil. The threshold rainfall amount in which runoff occurs was 10.50 mm in sandy loam, 7.76 mm in loam and 17.40 mm in clay loam. These different phases of water flow by soil texture could be used to suggest guidelines for the best management practice of the farming slope land.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.533-539
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• 2014

Mine wastes such as acid mine drainage (AMD) can cause the detrimental effects on surrounding environment, thereby eventually threatening human health. Main objective of this study was to evaluate the neutralizing effect of fly ash (FA) as a stabilizing material AMD. Field plot was constructed in a coal waste depot which has caused aluminium-whitening adjacent to the stream. Different mixing ratios of FA were applied on a top of the soil, and then the physicochemical properties of runoff and soil were monitored. Constructed plots were as following: control (mine waste only (W)), mine waste + 20% ($w\;w^{-1}$)of FA (WC20M), mine waste + 40% ($w\;w^{-1}$)of FA (WC40M), and WC40M dressed with a fresh soil at the top (WC40MD). Result showed that initial pH of runoff in control was 5.09 while that in WC40M (7.81) was significantly increased. For a plot treated with WC40M, the concentration of Al in runoff was decreased to $0.22mg\;L^{-1}$ compared to the W as the control ($4.85mg\;L^{-1}$). Moreover, the concentration of Fe was also decreased to less than half at the WC40M compared to the control. Application of FA can be useful for neutralizing AMD and possibly minimizing adverse effect of AMD in mining area.

• 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.

• Journal of Korean Society on Water Environment
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• v.40 no.3
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• pp.131-139
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• 2024

This study investigated the chemical properties of Organic Soil Amendments (OSAs) made from organic waste. It also assessed the effectiveness of using these OSAs in the soil layer of Green Infrastructure (GI) to reduce stormwater runoff and non-point source pollutants. The goal was to improve the national environmental value through resource recycling and contribute to the circular economy transformation and carbon neutrality of urban GI. The OSAs used in this study consisted of spent coffee grounds and food waste compost. They were found to be nutrient-rich and stable as artificial soils, indicating their potential use in the soil layer of GI facilities. Applying OSAs to bio-retention cells and permeable pavement resulted in a reduction of approximately 11-17% in stormwater runoff and a decrease of about 16-18% in Total Phosphorus (TP) discharge in the target area. Increasing the proportion of food waste compost in the OSAs had a positive impact on reducing stormwater runoff and pollutant emissions. This study highlights the importance of utilizing recycled resources and can serve as a foundation for future research, such as establishing parameters for assessing the effectiveness of GI facilities through experiments. To enable more accurate analysis, it is recommended to conduct studies that consider both the chemical and biological aspects of substance transfer in OSAs.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.671-676
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• 2015

Control of surface runoff from upland soil is essential to reduce nonpoint source pollution. The use of non-woven fabric as a soil cover can be helpful to control surface runoff. The field experiment was conducted to evaluate the furrow cover effects of black non-woven fabric on the nutrient discharge from upland soil used for red pepper cultivation. The experimental plots consisted of chemical fertilizer (CF), cow manure compost (CMC), and pig manure compost (PMC) treatment. Each nutrient material treatment plot has control (no furrow cover (NFC)) and black non-woven fabric cover treatment, respectively. The amount of nutrient application was chemical fertilizer of $190-112-149(N-P_2O_5-K_2O)kgha^{-1}$, cow manure compost of $29.5tonha^{-1}$, and pig manure compost of $7.9tonha^{-1}$ as recommended amount after soil test for red pepper cultivation. Compared to control (NFC), furrow cover treatment with black non-woven fabric reduced the amount of T-N discharge by 50% at CF treatment, 36.9% at CMC treatment, and 44.8% at PMC treatment. Furrow cover treatment with black non-woven fabric reduced the amount of T-P discharge by 37.1% at CF treatment, 49.9% at CMC treatment, and 63.4% at PMC treatment compared to control (NFC). The production of red pepper did not show significant difference. There was no weed occurring in furrow cover treatment plots with black non-woven fabric. Results from this study showed that the furrow cover with black non-woven fabric could play a significant role in reduce nutrient discharge from upland soil used for red pepper cultivation.

• Journal of Korean Society on Water Environment
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• v.23 no.4
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• pp.474-481
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• 2007

With population growth, industrialization, and urbanization within the watershed, the hydrologic response changed dramatically, resulting in increases in peak flow with lesser time to peak and total runoff with shortened time of concentration. Infiltration is directly affected by initial soil moisture condition, which is a key element to determine runoff. Influence of the initial soil moisture condition on hydrograph analysis should be evaluated to assess land use change impacts on runoff and non-point source pollution characteristics. The Long-Term Hydrologic Impact Assessment (L-THIA) model has been widely used for the estimation of the direct runoff worldwide. The L-THIA model was applied to the Little Eagle Creek (LEC) watershed and Its estimated direct runoff values were compared with the BFLOW filtered direct runoff values by other researchers. The $R^2$ value Was 0.68 and the Nash-Sutcliffe coefficient value was 0.64. Also, the L-THIA estimates were compared with those separated using optimized $BFI_{max}$ value for the Eckhardt filter. The $R^2$ value and the Nash-Sutcliffe coefficient value were 0.66 and 0.63, respectively. Although these higher statistics could indicate that the L-THIA model is good in estimating the direct runoff reasonably well, the Antecedent Moisture Condition (AMC) was not adjusted in that study, which might be responsible for mismatches in peak flow between the L-THIA estimated and the measured peak values. In this study, the L-THIA model was run with AMC adjustment for direct runoff estimation. The $R^2$ value was 0.80 and the Nash-Sutcliffe coefficient value was 0.78 for the comparison of L-THIA simulated direct runoff with the filtered direct runoff. However there was 42.44% differences in the L-THIA estimated direct runoff and filtered direct runoff. This can be explained in that about 80% of the simulation period is classified as 'AMC I' condition, which caused lower CN values and lower direct runoff estimation. Thus, the coefficients of the equation to adjust CN II to CN I and CN III depending on AMC condition were modified to minimize adjustments impacts on runoff estimation. The $R^2$ and the Nash-Sutcliffe coefficient values increase, 0.80 and 0.80 respectively. The difference in the estimated and filtered direct runoff decreased from 42.44% to 7.99%. The results obtained in this study indicate the AMC needs to be considered for accurate direct runoff estimation using the L-THIA model. Also, more researches are needed for realistic adjustment of the AMC in the L-THIA model.