• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.237-241
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• 2012

많은 건설사업장의 경우 토사 유출에 따른 고농도 탁수가 발생하며, 그 탁도를 낮추기 위해 침전지 혹은 토사탈수백 등의 Best Management Practices(BMPs)를 이용한다. 본 연구에서는 유입되는 탁수에 고분자응집제인 polyacrylamide(PAM)를 액상으로 주입하고, 침전지와 토사탈수백을 통해 탁도를 저감하는 field-scale 실험을 수행하였다. 일반적으로 침전지 중간에는 유입되는 물의 힘을 분산시키기 위해 배플이라는 구조물이 설치되는데, 본 연구결과에 따르면 PAM을 통한 화학적 처리 없이 배플 자체로는 탁도를 낮추는 데 그 효과가 낮았으나, PAM주입을 할 경우 배플 설치 여부에 상관없이 90-98%까지 방류수 탁도를 낮출 수 있는 것으로 나타났다. 침사지 이후에 설치한 토사탈수 백은 그 효과가 낮았으나, 침사지 없이 토사탈수백만 사용할 경우 PAM을 이용한 화학적 처리 없이는 만족할 만한 방류수 탁도를 기대하기 어려웠다. 본 연구결과는 향후 미국에서 면적 10에이커 이상의 공사현장에 적용되는 탁도 규제에 대한 대응 방안으로 PAM을 이용한 탁수 처리의 효용성을 보여준다.

• Journal of the Korean Society of Visualization
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• v.19 no.2
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• pp.63-73
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• 2021

It is essential to accurately predict the change in water level, velocity, and flow rate for each passage of the grit chamber according to the operating conditions of the pump. In this study, VOF multiphase flow analysis was performed, and the flow characteristics of the grit chamber were predicted. As a result of simulations, the sedimentation phenomenon after the entrance of the grit chamber channel is expected to occur on the side walls. When 6 channels are used, the average speed of the channels is about 52% of the design standard, and when 4 channels are used, the value increases to 74% of the design standard. The average water level in the channels tends to decrease as the flow velocity increases, and the water level in the absorption well with a larger flow rate is maintained lower than that in the absorption well with a smaller flow rate.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.4
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• pp.245-250
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• 2004

Farmers typically apply the dressed soil (coarse saprolite) for various reasons in the sloped upland with high altitude in Kangwon province. However, little researches on the impacts of application of dressed soil in uplands were conducted. Therefore, it is necessary to assess soil quality in this area and to study adverse effects on soil and water due to application of dressed soil. Coarse saprolite itself showed signiScantly poor chemical properties, Particularly P and organic matter contents were not enough for crops to grow. With respect to biological qualities such as enzyme activity and microbial population, coarse saprolite itself showed poor qualities. For example, bacterial population in coarse saprolite contains six times or ten times smaller populations. Based on survey at Jawoon-ri in Hongchon-gun, this region is susceptible for soil erosion due to massive amounts of coarse saprolite application, undesirably long slope length, etc. When weestimated soil loss, more than 40% of farming field in this region exceeded $11.2MT\;ha^{-1}\;yr^{-1}$. According to experiment by installing sediment basins. the sediment basin with up-down tillage and application with dressed soil had the highest soil loss and runofT, while the sediment basin with contour tillage and without soil dressing showed the lowest soil erosion and runoff.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.3
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• pp.383-394
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• 2013

A sedimentation basin is used to remove suspended sediments which can cause abrasive and erosive wear on hydraulic turbines of hydropower plants. This sediment erosion not only decreases efficiency of the turbine but also increases maintenance costs. In this study, the three-dimensional numerical simulations were carried out on the overseas hydropower project. The simulations of flow and suspended sediment concentration were obtained using FLOW-3D computational fluid dynamics code. The simulations provide removal efficiency of a sedimentation basin based on particle sizes. The influence of baffles on the flow field and the removal efficiency of suspended sediments in the sedimentation basin has been investigated. This paper also provides the numerical simulations for sediment-induced density currents that may occur in the sedimentation basin. The simulation results indicate that the formation of density currents decreases the removal efficiency. When a baffle is installed in the sedimentation basin, the baffle provides intensive settling zones resulting in increasing the sediments settling. Thus the enhanced removal efficiency can be achieved by installing the baffle inside the sedimentation basin.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.299-303
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• 2011

사전재해영향성검토 협의제도는 개발로 인해 발생할 수 있는 재해유발 요인을 사전에 검토하여 이를 사전에 제거하는 것이 목적이다. 사전재해영향성 검토는 1996년부터 시행한 재해영향평가의 한계점을 보완하기 위하여, 2005년 개정된 자연재해대책법에서는 사전재해영향성 검토협의제도를 포함하였으며, 2005년 8월 17일 동법 시행령을 개정 공포하여 사전재해영향성검토 협의제도를 본격적으로 시행하게 되었다. 본고에서는 사업 대상 지구를 "부산장안지구 택지개발사업(1단계)"로 선정하였으며, 개발에 따른 재해 발생요인, 즉 유출량 증가에 따른 하류부의 홍수피해 가중, 토공 공사에 따른 토사유출량 증가, 절 성토계획 따라 유발되는 사면의 불안정에 대한 사전검토를 목적으로 하였다. 사업시행에 따른 개발중 토사유출량의 증가와, 개발후 홍수유출량의 증가로 재해의 위험이 예상되어 개발 중의 임시저류지 겸 침사지 2개소와 개발 후의 영구저류지 1개소를 계획하여 홍수유출량을 $2.48m^3/sec$을 줄이고, 토사유출을 90% 포착하였다.

• Proceedings of the Korean Institute of Landscape Architecture Conference
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• 2021.10a
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• pp.109-110
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• 2021

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.185-186
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• 2022

In this study, a numerical analysis was conducted using a two-dimensional diffusion-wave analysis model to analyze the validity about the application of eco-friendly prefabricated rainwater detention system in grit chamber and permanent pond. As a result of the analysis, it is confirmed that the flood prevention effect, such as a decrease in peak flow rate and a delay in peak time, is excellent, so it is considered reasonable to apply eco-friendly prefabricated rainwater detention system in grit chamber and permanent pond.

• Journal of Korean Society of Forest Science
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• v.106 no.2
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• pp.196-203
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• 2017

Quarrying industry is typical industry that troubled between the market and government regulations in the forestry. Especially, it is difficult to consider aspects of economics and environment, landscape, disaster at the same time. Therefore, Quarrying industry need revised statutes according to regulatory reform and mitigation. This study conducted to provide basic data for regulatory reform and mitigation in quarrying industry. We surveyed 22 article of mountainous districts management act and lower statutes to employers and business interests on quarry 55 places in the Republic of Korea. As a result, fulfillment status of environmental damage reduction and disaster prevention were satisfactory. But fulfillment status of landscape damage reduction were not applicable. This result is due to the social mood that emphasizes the forest landscape. But there is need to improve the efficiency of grit chamber through present standard on effluent(water pollution prevention). In conclusion, policies should be established for realistic regulation and developed industry to quarrying industry.

• Journal of Korea Water Resources Association
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• v.32 no.4
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• pp.457-467
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• 1999

No complete methods for estimating soil loss, included by rain storms, from a small watershed are available yet, and the best recommended method is to use measured data from the watershed. When no measured data is available from the watershed, empirical models for estimating the soil loss, such as the Universal Soil Loss Equation(USLE), is well recommended in practice. For using this equation, it is necessary to estimated the rainfall erosivity, commonly expressed as R, of the watershed. In this study, first we collected data of the probable rainfalls with the return periods of 2, 5, 10, 20, 30, 50, 80, 100, 200, and 500-yr and with the duration hours of 0.5, 1, 2, 3, 6, 12, and 24-hr. Using this data, we calculated the design values for R for the return period of 24-hr at each major rainfall-measuring station nationwide. Then we constructed the iso-erodent map of Korea for each return period of the 24-hr design storm. This study shows that the 24-hr duration iso-erodent map of the 5-yr return period is very similar to the annual average iso-erodent map of Korea. This study also shows that the 24-hr duration R-values of a certain return period can be estimated by multiplying certain parameters, obtained from this study, to the 24-hr duration R-values for the 5-yr return period or the annual average R-values. Finally, the R-values of the design storm with the 24-hr return period obtained from this study can be used for designing the settling basins at small watersheds.

• Journal of Environmental Science International
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• v.25 no.8
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• pp.1191-1206
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• 2016

Transported deposit was accumulated in a grit chamber built at the mouth of Yeocheoncheon in 1987 with the intention of blocking the influx of sediment into the Ulsan-harbor. This study attempted to analyze the effects of the transported deposit on the water quality at Yeocheoncheon. Only one episode of dredging has been performed in the approximately 25 years since the grit chamber were built, leading to the formation of stagnant water in the grit chamber due to a large amount of transported deposit. The deposit has a relatively high organic content, in the range of 11.7-25.9% (mean 18.3%). It appears that the main reason for the upstream transport of water pollution from the mouth of the Yeocheoncheon is the tides. The effects of organic content and stagnant water on water quality were analyzed using WASP. Moreover, the changes in water quality arising due to the removal of the grit chamber were analyzed. Results indicated that BOD improved by 18.8-100%, while T-P improved by 90.0-617.4%, between the grit chamber and Hanbi-Gyo, which is located 1.3 km away from the grit chamber.