• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.467-467
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• 2016

암거는 일반적으로 용수나 배수용의 수로가 도로, 철도, 제방 등의 아래에 매설 된 수로를 지칭한다. 이러한 암거는 산업발전으로 사회기반시설의 신설 및 확충, 재정비 등으로 많이 활용되고 있다. 최근 들어 기후로 인한 재해가 급증하면서 이러한 시설물에 대한 안정성 및 관리에 대한 관심이 높아지고 있는 것이 현실이다. 특히 소하천은 집수면적 및 유로연장이 짧고 하상경사가 급하기 때문에 홍수에 취약하다. 즉, 빨라진 유속으로 인해 구조물 주변의 세굴에 의한 유실, 토사유출로 인한 하상퇴적, 부유물로 인한 차단으로 인해 통수에 지장을 받아 피해가 발생하게 된다. 이러한 암거시설물 피해는 2차 피해로 이어질 수 있으며 사회기반시설 파괴로 도시기능이 마비되고 인근 주변지역에 침수로 인한 재산 및 인명피해까지 발생시킬 수 있는 피해 잠재능력을 보유하고 있다. 그러나 피해에 대한 예방대책은 유지관리를 통해 지속적으로 관리하는 것이 대부분의 지침 등에 소개된 내용들이다. 본 연구에서는 암거를 대상으로 암거의 폐색으로 인해 암거주변에서 변화되는 흐름특성을 축소모형을 통해 검토하고자 하였다. 암거 축소모형실험은 1.5m 폭을 갖는 직선수로에서 수행하였으며, 암거모형은 도로암거표준도(2008)를 참조하여 $3m{\times}3m$ 수로암거를 대상으로 1/10 축소모형을 제작하였다. 암거유입부 퇴적으로 인한 암거의 차단률(차단면적/암거단면적)은 차단이 발생하지 않는 0% 조건에서부터 10%, 20%, 30%, 40%, 50% 조건에 대해 실험을 수행하였다. 실험결과 차단에 따른 암거 상류단의 수위는 차단이 없는 암거의 경우에 비해 차단율이 높아질수록 암거유입부 수위는 20.4% ~ 82.7% 상승하는 것으로 나타났다. 암거의 차단률이 40% 이상일 경우 높아진 수위로 인해 암거통로의 윗상면부까지 다다르고 있으며 50%일 경우 암거를 통과하는 흐름이 자유수면흐름이 아닌 오리피스 흐름이 발생하는 것으로 나타났다. 암거유입부 차단으로 인한 암거주변의 최대유속은 암거 직하류부에서 주로 발생하여 암거 유출부에서의 최대유속은 차단율이 증가할수록 선형적으로 증가하는 것으로 나타났으며 암거 유출부에서의 유속은 차단전의 조건(0%) 대비 4.2% ~ 35.5% 까지 상승하는 것으로 나타났다. 이와 같은 결과를 토대로 고려하였을 때 대부분 산지부에서 설치되는 암거의 경우 유속이 불가피하게 증가하게 됨으로 유속에 따른 유속조절방안(차단 및 우회시설) 및 세굴대책을 세워야 할 것으로 판단된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.50-50
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• 2020

하천, 강어귀 및 해안 지역의 점착성 유사는 흐름 내에 입자의 충돌에 의한 흡탈착으로 인해 다양한 크기의 플록을 형성한다. 이 플록은 오염물과도 군집을 형성하여 하상이 퇴적되는 경우가 많으며 홍수 등과 같은 외부 충격으로 인해 재부 되어 하천 환경 및 생태계에 악영향을 미친다. 군집의 형성은 화학적인 결합과 물리적인 응집으로 분류할 수 있는데, 미세 점착성 유사의 군집형성에 대한 연구는 주로 화학적인 결합에 대한 연구가 활발하다. 반대로 물리적인 결합 혹은 외부 충격에 대한 플록형성 매커니즘에 대한 연구는 미비한 실정이다. 따라서, 본 연구에서는 교반기를 활용한 실험을 통하여 점착성 유사에 대한 물리적인 흡탈착 과정을 분석하였다. 유입된 점착성 유사를 교반기로 외부충격을 주어 흡착과 탈착하는 정도를 탁도와 농도를 통해 정량화하였다. 실험은 원통 수조에서 수행되었으며, 교반기의 RPM을 조절하면서 외부충격의 강도를 조절하였다. 초기 실험을 통해 탁도-농도의 관계를 제시하였고 이를 활용하여 교반강도와 점착성 유사의 농도를 분석하였다. 실험 결과 교반강도가 증가할수록 플록 형성이 활발하게 진행되었으나, 일정 교반강도 이상에서는 다른 흡착 과정을 보였다. 이를 토대로 점착성 유사의 흡탈착의 임계값을 제시하였다. 향후 본 연구결과와 유속 혹은 난류강도 등의 하천특성과 연관성을 분석한다면 하천 내 오염물 관리에 효과적으로 사용될 것으로 기대된다.

• Journal of the Society of Disaster Information
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• v.9 no.2
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• pp.145-152
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• 2013

This study was conducted to improve the Nonpoint-source pollutant treatment plant efficiency and maintenance. Field and laboratory permeability test were conducted three times each before and after displacement. The removal efficiency such as TSS, BOD, CODmn, T-N, and T-P were investigated from the year of 2006 to 2011. The coefficient of permeability right after displacement was calculated to be $1.07{\times}10^{-3}(cm/s)$, coefficient of permeability after a year was calculated to be $0.88{\times}10^{-3}(cm/s)$, and after five years, it was calculated to be $0.3{\times}10^{-3}(cm/s)$ and accordingly, the amount of infiltration decreased. In case of the removal efficiency, it generally tended to decrease, but it showed the higher rates than the expected rates BOD 40%, SS 76%, T-N 39% and T-P 53%. It is concluded that displacement cycle should be at least five years and that dredging cycle should be at least three months and at most one year.

• Proceedings of the KAIS Fall Conference
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• 2012.05a
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• pp.348-351
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• 2012

4대강 살리기 사업 등 대형 사업의 건설 및 시행에 의한 환경적 영향에 대한 예측과 적절한 수질관리 대안을 마련하기 위해서는 적절한 수문 수질모델을 이용하는 것이 필수적이며, 국내 대형 국책 사업 또는 중요 환경영향평가에서는 계속적으로 수질모델이 사용되고 그 적용 범위는 더욱 증가 될 전망이다. 따라서 이들 수질 모델의 사용에 있어서 예측의 정확도 및 신뢰도를 제고하는 것은 매우 중요한 일이라 할 수 있을 것이다. 특히 4대강 살리기 사업에 의해 다수의 보가 하천 내에 건설되고 준설이 실시됨에 따라 하천 내의 수리 동역학적 특성 및 수질특성이 변화할 것으로 예상되며, 적절한 수질관리 대책을 수립하기 위해서는 사업에 의한 수리 및 수질 특성 변화를 예측하고 시나리오를 분석할 있는 모델링 시스템을 구축하는 것이 필수적이다. 따라서 본 논문에서는 보 건설에 따른 다양한 수리 및 수질 특성 변화를 예측하기 위해 모의 가능 모형들을 조사하고, 국 내외 적용사례 분석을 통해서 현재 가장 많이 적용되고 있는 모형들을 선별하였다. 이를 토대로 모형 별 성능을 비교 분석하여 모형별 적용성을 검토하였다. 검토결과 신설보 설치에 따른 하천 수리 특성의 변화, 부유물질 및 동반 오염물질에 의한 수질 변화 등의 고려가 가능하며, 동적상태 모형으로 하천에서의 불연속적인 흐름에 따른 모의, 수심방향으로의 모의가 가능한 EFDC 모형이 보 설치에 따른 국부적인 영향을 자세하게 파악하는데 가장 적절한 모형으로 파악되었다.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.9
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• pp.495-504
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• 2017

An amphibious scrubbing/suction dredging machine with cylindrical rotating brush, housing, and turbidity barrier was newly-developed to remove both sediments with about 10 cm thickness and periphyton attached on various structures in urban water-circulating systems through the scrubbing, suction, and dredging processes. Based on the field application and long-term monitoring, the increase in both suspended solids (SS) and turbidity of water during the scrubbing, suction, and dredging processes was negligible (p>0.05). In some cases, the turbidity of water initially increased, however, the turbidity was stabilized within 20 minutes from the start of dredging processes. The concentration changes in TN and TP of water were not statistically different (p>0.05) before and after the scrubbing, suction, and dredging processes, indicating that benthic nutrients released from sediments were not significantly diffused, and were not supposed to cause significant water pollution. Also, water treatment facilities along with an amphibious scrubbing/suction dredging machine could be more effective since the removal of contaminant loadings through the scrubbing, suction, and dredging processes was much greater than that through simple coagulation/precipitation processes. Finally, GPS-based realtime tracking and operation program have been developed and applied in various urban water-circulating systems, and development of driver cooperative autonomous driving system is in progress to eliminate the need for manual driving of an amphibious scrubbing/suction dredging machine.

• Korean Journal of Environmental Biology
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• v.27 no.2
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• pp.183-190
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• 2009

Characterization of the analysis of forest vegetation, soil environmental conditions and water quality were performed from March 2003 to March 2007. The two basins were characterized by cultivated area (Kaesim reservoir) and mountain area (Jangchan reservoir), and divided into eleven small basins, where dynamics of pollutants, forest vegetation and soil environmental conditions were surveyed. The vegetation can be divided into 10 types by $Z\ddot{u}rich$-Montpellier school's method. Pearson coefficients between vegetation type and water quality were correlated with dissolved oxygen (DO) in the Quercus variabilis community at the 5% level and total phosphorus (TP) in the Larix leptolepis plantation at the 1% level. Especially total phosphorous and total nitrogen increased in small basins where the proportion of cultivated and residential area increased. The analysis of influences of pollutant discharge on water quality showed that pollutant charge was very low in forest land area ($Y_{T-P}$=-0.0017X+0.2215, r=0.16, $Y_{COD}$=- 0.0395X+8.5051 r=0.47). The soil types of western area were comparatively simple, but those of eastern area were complicated with regosols, red-yellow soils, lithosoles, etc. The pH, total solid (TS) and volatile substance (VS) of the forest and agricultural land soils collected in each site were 5.4~6.9, 75.8~80.2%, and 3.80%~5.80%, respectively. According to the analytical result of soil environmental conditions, heavy metal contents fell short to the mean value of natural conditions. Runoff amount (Y) and depth of topsoil (X) were negatively correlated, $Y_{ron}=-1.0088X_{top}+35.378$ (r=0.68). The correlation was much lower in up-stream but much higher in down-stream, because permeation into soil particle was larger on down-stream due to its more or less gentle slope. Pearson coefficients between soil pH and water pH were statistically significant at 1% level.

• Journal of Wetlands Research
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• v.16 no.4
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• pp.463-476
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• 2014

The riverine wetlands located in the riverside bring about social conflicts through confrontation between flood control value through flood control project and ecological preservation value of riverine wetland. In this study, we identified the importance of both values through analysis of economic feasibility of flood control and ecological values of riverine wetland, and tried to suggest management plans for riverine wetland considering both of flood control safety and ecological preservation through these results. For this, we calculated the expected annual flood damage of Imjin River using the multi-dimensional flood damage analysis(MD-FDA), and calculated the total value of riverine wetland using the contingent valuation method(CVM) to estimate preservation value of riverine wetland. The result of the analysis shows that the Imjin River needs flood control project and the ecological preservation of riverine wetland is also important. Therefore, the establishment of the management plan for protecting riverine wetland is also needed. As a result, the Imjin riverine wetland was classified as the area where sedimentation continues to take place, and the flood water level to rise. On the basis of the analyzed results, it is judged that the Imjin River needs flood control for public safety and ecological consideration for ecosystem preservation in the river improvement project. So, the stepwise river improvement is desirable to protect riverine wetland and minimize ecosystem disturbance. The results is expected to be made good use as the basic study for establishment of institutional river management plans considering flood control project and riverine wetland preservation in the future.

• Journal of Korea Water Resources Association
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• v.34 no.5
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• pp.487-497
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• 2001

Investigated data on Lake Okjeong were used for the simulation of water quality. According to the simulation results, the effective scheme of water quality management on reservoir has been proposed. It has been recognized that the water quality of Lake Okjeong is under eutrophic and mesotrophic condition even though there are seasonal variation. The water quality of lake is mainly affected by the inflow of pollutant load from watershed. Therefore, to estimate and quantify the accurate amounts of pollutants flowing into reservoir is absolutely necessary for the effective management of water quality on Lake Okjeong. When the pollutant load measured during 7 different rainy periods in 1999 was compared with total pollutant load in 1999. TN and TP measured during 7 different rainy periods showed almost 50% of total pollutant load. In case of SS, it was 72.8%. On the other hand, the rainfall amount measured during the 7 different rainy periods was about 17.5% of total rainfall amount in 1999. Release rate of TP shows 11.92 mg/L at fish farm site and 0.2∼1.9 mg/L at monitoring station of water quality on Lake Okjeong, and which is considered to be less than that of other foreign reservoirs under the circumstances of anoxic condition. For the effective management of water quality on Lake Okjeong. WASP5 water quality simulation model has been applied and verified, and the verified model was used to propose the effective scheme of water quality management. In this case, 6 different scenarios were applied, by changing the amount of inflow of pollutant load in each subbasin. The most effective scheme has turned out that pollutant load generated from Imsil and Gwanchon subbasin should be reduced, and the best way to improve the water a quality is to reduce the pollutant load at every subbasin. According to the simulation result, wastewater treatment facility should be located at every subbasin.

• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.3
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• pp.74-80
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• 2001

Due to floating marine debris, seabed litters, dead shellfishes and polluted sediments, etc. , which are mainly caused by fishery activities in a large scale around the coastline, expansion of industrialized areas from economic development and drastic increase of free time by the improved standard of living, Korean coast is believed to be cast beyond the self purification of marine ecosystem. Seabed litters, if not remedied in a timely manner, will eventually lead to the overall disorder of benthic ecosystem. Thus, in order to prevent marine ecosystem from being thrown into confusion by seabed litters and to restore ocean environments, it is reasonable to investigate the current status of the seabed litters by carrying out an extensive examination on them and to equip ourselves for marine debris with an systemized tool that provides supports to the building process of an efficient methodology of litters disposal through managing related data appropriately. As an primary step to this goal, a systematic method of investigation is presented in this paper. With this methodology, the present state of the seabed titters is properly understood for the specified list of ports.

• Journal of Wetlands Research
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• v.9 no.3
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• pp.51-61
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• 2007

In natural river, river-bed change is greatly influenced by the various factors such as river improvement, change of watershed land use, construction of dam and reservoir, gravel mining, and so on. The knowledge about river-bed change in the river is essential in the river modification, wetlands plan, and maintaining stable alluvial rivers. In this study, river-bed change in the future was predicted by investigating river channel characteristics which play dominant role in the formation of channel and based on the numerical model through river survey and the grain size analysis. The Proposed investigation and model was applied to the Geum river and the Miho stream which have been experienced river degradation due to river aggregate dredging and now seams to be stable. The result of potential river-bed change which was estimated by investigating channel characteristic including slope of channel, friction velocity, and so on is similar to that which was estimated based on the numerical model. It was found that the Geum river and the Miho stream will be stable. In the future, if considering the characteristics of river channel which is estimated by the river-bed scour, sediment, and so on, it is possible that river improvement and wetland restoration plan are established stably and naturally.