• Journal of Environmental Science International
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• v.7 no.5
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• pp.581-590
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• 1998

This st at the development of the adequate sediment yield formulas in Wi-Stream basin ; IHP representative basin in Korea. As a result of applying outstanding sediment yield formulas among the existing formulas, it is analyzed that including the Engelund ＆ Hansen formula, Yang formula is proper to the Wi-Stream basin. And as a result of sensitivity analysis to the sediment parameters it is analyzed that Rijn and Actors ＆ White formula is more sensible than any other formulas which has been applied the velocity and depth among the parameters. Also, Engelund ＆ Hansen and Yang formula is less sensible than any other formulas. In Wi-Stream basin, it is analyzed that Yang and Engelund ＆ Hansen formula is the most suitable sediment yield formula in this study. But because the existing formulas had been developed in foreign countries and applied the foreign natural livers and reservoirs, it makes careful use of Korean alluvial river and hoped that it will be developed the most adequate formula in Wi-Stream basin.

• Journal of Environmental Science International
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• v.6 no.5
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• pp.417-423
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• 1997

The objective of this study Is to supply basic data for large reservoir sedimentation research In future and make suggestions to maintain and opera능 the reservoir more of efficiently. At first, previous studios about the estimation of sediment yield rate were reviewed in Korea. And the discharge rating curves of upstream stage gauging stations and the correlation between dam Inflow and stage discharge were analyzed. With the analysis results, the spec유c sediment rate of Soyanggang dam was estimated as 608 m3/km2/yr. It was similar to that of Soyanggang dam feasibility study and 1994's field surveys of the reservoir than that of 1983's field surveys. Because the sediment rating curves were derived under the low discharge conditions, It needs to be checked under the flood conditions. However, the suggested methods such as flowrate analysis and sediment estimation will be useful to the sediment studios In future. Key words . reservoir sediment, sediment yield rate, rating curve, flowrate analysis.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.1
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• pp.36-43
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• 2007

This study was carried out to know how erosion control function of forests varies as forests develop in watersheds. The erosion control function among the forest welfare functions can be estimated by comparing sediment yield in stocked with non-stocked area. Sediment yield of reservoirs in stocked area were collected from farmland improvement associations. The sediment yields in non-stocked area were using USLE (Universal Soil Loss Equation) in the same reservoirs. Forests' erosion control function estimated by differences of the sediment yield between stocked and non-stocked area was static model because of no consideration on forest aging. Dynamic model was developed to consider a forest stand age. The model comprises the relationship between average forest age in watershed and sediment yield. The amount of sediment yield was different depending mother rocks. It decreased exponentially according to the forest's grow up. In case of igneous rock, the volume of sediment yield $Y_{ig}=1.4431e\;^{0.023x}$(x=average forest age), metamorphic rock $Y_{me}=4.7115e\;^{0.0694x}$, and sedimentary rock $Y_{se}=1.2808e\;^{0.028x}$.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.6
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• pp.39-48
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• 2010

Sediment yields from Imha watershed were simulated during 1993-2008 using Hydrologic Simulation Program-Fortran (HSPF). Using observed daily stream flow for 2004-2008 and hourly suspended solid concentration for three events during 2006, HSPF was calibrated and validated at the sites of Imha and Youngyang for stream flow and Dongchun and Jangpachun for sediment yield. The calibration and validation results represented high model efficiency for simulating daily stream flow and hourly suspended solid. The determination coefficients of calibration and validation were 0.90 and 0.81 for daily stream flow, and 0.91 and 0.86 for monthly stream flow, respectively. Based on model tolerances for calibration and validation of stream flow, HSPF performance for simulating stream flow represented 'very good'. The determination coefficients of calibration and validation were 0.94-0.96 and 0.95 for hourly sediment yields, respectively. The average yearly sediment yield during 1993-2008 was 122,290 ton/year and most of sediment yield (77 % of total yield) were generated from June to August. The calibrated HSPF simulated well the movement of water and eroded soil within Imha watershed.

• Spatial Information Research
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• v.13 no.1 s.32
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• pp.79-90
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• 2005

The purpose of this study is to estimate quantitatively soil loss and sediment yield in alpine farmland. For this purpose, Naerinchon watershed in Gangwon province was selected as our study area and total annual soil loss and sediment yield was estimated respectively by the Revised Universal Soil Loss Equation (RUSLE) model and the Sediment Delivery Distributed (SEDD) model. The results of this study clearly show that dry field areas have significant impact on the total soil erosion and sediment yield compared with other land use. Dry field areas represent only $2.6\%$ of the total area of the watershed but soil loss and sediment yield account for $10.9\%$ and $33.12\%$ of the total amount respectively Especially as with alpine farmland, this result is more clearly shown. These areas account for $1.8\%$ of the entire watershed but contribute to $7.7\%$ and $15\%$ of the total soil loss and sediment yield respectively. From the above results, we can know that alpine farmland is important source of soil loss and sediment yield and it is need to prevent and control. soil erosion from alpine filmland urgently.

• Economic and Environmental Geology
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• v.40 no.1 s.182
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• pp.103-113
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• 2007

The empirical USLE and the physically-based GeoWEPP which were distributed model linked with GIS (Geographical Information System) were applied to small natural catchment located in Icheon-si, Gyeonggi-do, South Korea. The results using by two models were total sediment yield from study catchment between January, 2004 and January, 2005. During the study period, the observed total sediment yield was 270.54 ton and the total sediment yield computed by USLE and GeoWEPP model were 358.1 ton and 283.30 ton, respectively. Each of results computed by USLE and GeoWEPP overestimated more than the observed total sediment yield, but, based on the results, the total sediment yield computed by GeoWEPP approximated to the observed result. We suggest that the reason why the total sediment yield using by models overestimated was that computed amounts by two models did not contain the amount of suspended sediment flowed over the weir.

• Journal of Korea Water Resources Association
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• v.34 no.3
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• pp.199-207
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• 2001

Due to the nationwide development, sediment yield has to be estimated to design the sedimentation basin which is used to minimize the effects of construction or disturbing the natural soil condition. But there is no proved equation for the estimation of sediment yield in Korea. Therefore, applicability and the limitation of RUSLE (revised universal sediment loss equation) sediment yield equation is examined for the construction sites, where the rainfall and sediment data are available. General mistakes in estimation of the RUSLE parameters are also discussed. It is found that RUSLE could be applied in Korea as long as the sediment delivery ratio was considered. Appropriate estimation method of sediment delivery ratio are also proposed.

• Journal of Environmental Science International
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• v.22 no.5
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• pp.599-608
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• 2013

Jeju island, which is located along the moving path of typhoon, suffers from flooding and overflow by torrential rain. So abrupt runoff occurring, damages of downstream farm field and shore culturing farms are increasing. In this study, Oaedo stream, one of the mountainous streams on Jeju island, was selected as the basin of study subject and was classified into 3 sub-basins, and after the characteristics of subject basin, the soil erosion amount and the sediment delivery of the stream by land usage distribution were estimated with the use of SATEEC ArcView GIS, the sediment yield amount of 2000 and 2005 was analyzed comparatively. As a result of estimating the sediment yield amount of 2000, the three sub-basins were respectively 12,572.7, 14,080 and 157,761 tons/year. and sediment yield amounts were estimated as 35,172.9, 5,266 and 258,535 tons/year respectively in 2005. The soil erosion and sediment yield amount of 2005 using single storm rainfall were estimated high compared with 2000, but for sub-basin 2, the values rather decreased due to changes in land use, and the land coverage of 2005, since there are many classifications of land usage compared with 2000, enabling to reflect more accurate land usage condition, could deduce appropriate results. It is anticipated that such study results can be utilized as basic data to propose a direction to predict the amount of sediment yield that causes secondary flooding damage and deteriorates water quality within detention pond and grit chamber, and take action against damages in the downstream farm field and shore culturing farms.

• Korean Journal of Agricultural Science
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• v.47 no.4
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• pp.803-814
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• 2020

Managing erosion control dams requires the annual average sediment yield to determine their storage capacity and time to full sediment-fill and dredging. The GeoWEPP (Geo-spatial interface for Water Erosion Prediction Project) model can predict the annual average sediment yield from various land uses and vegetation covers at a watershed scale. This study assessed the GeoWEPP to determine the annual average sediment yield for managing erosion control dams by applying it to five erosion control dams and comparing the results with field observations using ground-based LiDAR (light detection and ranging). The modeling results showed some differences with the observed sediment yields. Therefore, GeoWEPP is not recommended to determine the annual average sediment yield for erosion control dams. Moreover, when using the GeoWEPP, the following is recommended :1) use the US WEPP climate files with similar latitude, elevation and precipitation modified with monthly average climate data in Korea and 2) use soil files based on forest soil maps in Korea. These methods resulted in GeoWEPP predictions and field observations of 0 and 63.3 Mg·yr-1 for the Gangneung, 142.3 and 331.2 Mg·yr-1 for the Bonghwa landslide, 102.0 and 107.8 Mg·yr-1 for the Bonghwa control, 294.7 and 115.0 Mg·yr-1 for the Chilgok forest fire, and 0 and 15.0 Mg·yr-1 for the Chilgok control watersheds. Application of the GeoWEPP in Korea requires 1) building a climate database fit for the WEPP using the meteorological data from Korea and 2) performing further studies on soil and streamside erosion to determine accurate parameter values for Korea.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.1
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• pp.111-117
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• 2015

We investigate the influence of spatial rainfall distribution on hillslope soil erosion through laboratory experiments. Two distinct spatial distributions are examined in this study, i.e., rainfall concentrated on central area versus upper area of hillslope. During the entire period of 8 hours for each experiment, direct runoff, subsurface flow, and sediment yield are measured at high temporal resolution (10 minutes). Compared to the case that rainfalll concentrated on central area, upstream concentrated rainfall results in lower peak of the sediment yield curve while greater cumulative sediment yield. Cumulative sediment yield increases over time linearly but its growth rate shows a sudden decrease at around 2 hours. This should be taken into consideration when temporal variability of sediment yield is estimated from observed total amount, and demonstrates the necessity of measuring sediment yield at high temporal resolution.