• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.11a
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• pp.294-297
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• 2000

Heavy metals are extracted from Chonju stream sediment, roadside soils and sediments along Honam expressway, soils and tailings from mining area using partial ectraction in Standard Method, partial ectraction method with maintaining 0.1N of extraction solution and acid digestion. In samples having buffer capacity against acid, 0.1N of extraction solution can not be maintained and pH of extraction solution increases up to 8.0 when partial extraction in Standard Method is used. The averages and ranges of (heavy metals extracted using partial extraction in standard method, HPE)/(heavy metals extracted using partial extraction method with maintaining 0.1N of extraction solution, HPEM) values are 0.506 and 0.145~1.126 in Cd, 0.534~ and 0.078~0.928 in Zn, 0.461 and 0.041~1.715 in Mn, 0.359 and 0.011~0.874 in Cu, 0.195 and 0.018~1.785 in Cr, 0.710 and 0.003~3.075 in Pb, and 0.088 and 1.73$\times$10$^{-5}$ ~0.303 in Fe. These data indicate that the difference between HPE and HPEM is big in the order of Fe, Cr, Cu, Mn, Cd, Zn and Pb. It is quite possible that the partial extraction method in Standard Method of soil in Korea is not adequate for an assessment of contamination in area where buffer capacity of soil will be decreased or lost after a long term exposure of soils to environmental damage.

• Journal of Korean Society on Water Environment
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• v.25 no.6
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• pp.821-831
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• 2009

The study was aimed to assess the expected impact of climate change on the water cycle and soil losses in Daecheong Reservoir watershed, Korea using the Soil and Water Assessment Tool (SWAT) that was validated for the watershed in a previous study. Future climate data including precipitation, temperature and humidity generated by introducing a regional climate model (Mesoscale Model Version 5, MM5) to dynamically downscale global circulation model (European Centre Hamburg Model Version 4, ECHAM4) were used to simulate the hydrological responses and soil erosion processes in the future 100 years (2001~2100) under the Special Report on Emissions Scenario (SRES) A1B. The results indicated that the climate change may increase in the amount of surface runoff and thereby sediment load to the reservoir. Spatially, the impact was relatively more significant in the subbasin Bocheongcheon because of its lower occupation rate of forest land compared to other subbasins. Seasonally, the increase of surface runoff and soil losses was more significant during late summer and fall season when both flood control and turbidity flow control are necessary for the reservoir and downstream. The occurrence of extreme turbidity flow events during these period is more vulnerable to reservoir operation because the suspended solids that remained water column can be resuspended by vertical mixing during winter turnover period. The study results provide useful information for the development of adaptive management strategy for the reservoir to cope with the expected impact of future climate change.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.6
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• pp.103-110
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• 2019

The purpose of this study is to investigate the reaction mechanism of soil and bacteria solution by various mixing ratios. For this purpose, in order to understand the reaction mechanisms of microorganisms and weathered granite soil, the tests were carried out under various mixing ratios additives such as soil, bacteria solution, $Ca(OH)_2$ and fixture. The test results from this study are summarized as follows. Firstly, the reaction between the bacteria solution and fixture produced a precipitate called vaterite, a type of silicate and calcium carbonate. Secondly, as a result of SEM analysis, the resulting precipitates generated from the test results using the specimens with various mixing ratios except SW condition and the irregular spherical microscopic shapes were formed in the size of $150{\mu}m$ to $20{\mu}m$. In addition, it can be seen that the bacteria solution and the fixture reacted between the granules to form an adsorbent material layer on the surface, and the microorganisms had a biological solidifying effect when the pores are combined into hard particles. Finally, The XRD analysis of the sediment resulting from the reaction between the microorganism and the deposit control agent confirmed the presence of a type of calcium carbonate ($CaCO_3$) vaterite, which affects soil strength formation, as well as silicate($SiO_2$).

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.6
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• pp.23-30
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• 2016

Soil loss is an accompanying phenomenon of hydrologic cycle in watersheds. Both rainfall drops and runoff lead to soil particle detachment, the detached soil particles are transported into streams by runoff. Here, a sediment-laden water problem can be issued if soil particles are severely detached and transported into stream in the watershed. There is a need to estimate or simulate soil erosion in watersheds so that an adequate plan to manage soil erosion can be established. Universal Soil Loss Equation (USLE), therefore, was developed and modified by many researchers for their watersheds, moreover the simple model, USLE, has been employed in many hydrologic models for soil erosion simulations. While the USLE has been applied even in South-Korea, the model is often regarded as being limited in applications for the watersheds in South-Korea since monthly conditions against soil erosion on soil surface are not capable to represent. Thus, the monthly USLE factors against soil erosion, soil erodibility and crop management factors, were established for four major watersheds, which are Daecheong-dam, Soyang-dam, Juam-dam, and Imha-dam watersheds. The monthly factors were established by recent fifteen years from 2000 to 2015. Five crops were selected for the monthly crop management factor establishments. Soil loss estimations with the modified factors were compared to conventional approach that is average annual estimations. The differences ranged from 9.3 % (Juam-dam watershed) to 28.1 % (Daecheong-dam watershed), since the conventional approaches were not capable of seasonally and regionally different conditions.

• Journal of Korean Society of Rural Planning
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• v.9 no.4 s.21
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• pp.59-64
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• 2003

U.S. EPA의 BASINS (Better Assessment Science Integrating Point and Nonpoint Sources)에 통합되어 있는 HSPF (Hydrologic Simulation Program-Fortran)와 SWAT (Soil and Water Assessment Tool) 모형을 이용하여 Polecat Creek 유역의 유출과 유사량을 모의하였다. 모형의 보정을 위하여 1996년 9월부터 2000년 6월까지의 하천 유량 및 유사 농도 자료를 이용하였으며, 1994년 10월부터 1995년 12월까지의 관측자료를 이용하여 모형의 검정을 실시하였다. HSPF 모형에 의해 추정된 연 평균 유출량의 상대오차는 보정 및 검정기간에 각각 0.8%, 0.5%이었으며, S WAT 모형에 의해 추정된 연평균 유출량은 실측치와 각각 2.1%, 16.1%의 오차를 보였다. 연 평균 유사량을 비교하면, HSPF 모형이 보정 및 검정기 간에 각각 8.8%와 7.2%의 오차를 보인 반면에 SWAT 모형은 각각 40.0%, 188.4%의 차이를 보였다. HSPF 모형에 의해 추정된 월 평균 유출량 및 유사량의 상관계수는 보정기간에 대하여 0.94와 0.52이었으며, SWAT 모형에 의한 결과는 상관계수가 각각 0.84와 0.39이었다. 이상의 연구 결과에 의하면, HSPF 모형이 SWAT 모형보다 유출과 유사량을 관측치와 유사하게 모의함을 알 수 있었다. 하지만 입력 자료의 구축 및 모형의 적용에는 SWAT모형보다 많은 시간과 노력을 필요로 하였다.

• Journal of Ocean Engineering and Technology
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• v.17 no.2
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• pp.8-13
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• 2003

Soil, ground water, and sea bed are exposed to a continuous accumulation of polluted materials, causing serious environmental damage. It has been reported that such pollution causes a massive mortality of fish stock in rivers due to the resuspension of toxic chemicals, occurring during strong wind conditions. Therefore, it becomes apparent that there is an immediate demand for the restoration treatment of polluted river bed (or sea bed) sediment layers. Pollution levels of major rivers and ports, such as Paldang, Kyungan rivers, and Masan port, are becoming of great public concern, and are posing a serious environmental threat. In particular, the pollution of the Shi-hwa river has become a nation wide issue for the last few years. In spite of such public concern, the pollution levels of such rivers or ports are worsening everyday. In this study, an environmentally sound engineering package is introduced that helps to restore the polluted river bed or sea bed sediments. This engineering package consists of a suction facility, followed by a series of mechanical, chemical, and biological treatment units. The suction facility is designed to minimize secondary pollution that occurs from the resuspension of toxic materials during suction. The sea bed cleaning engineering package is designed to be installed on the top of a floating barge. Such a combination of environmental plant and shipbuilding technology provides a cost-effective solution, minimizing the transportation between suction and treatment facilities.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.6
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• pp.121-128
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• 2011

Long-term water treatment performance analysis was conducted for the constructed wetland treating agricultural tailwater. Studied wetland was established in 2001 and operated from June, 2002 to November, 2010. Wetland vegetation cover was shown over 90 % coverage after 2005. According to vegetation development, accumulation of sediment nutrient was observed; Organic Carbon, T-P and T-N. In addition, DO concentration and temperature was decreased in the constructed wetland output. An infiltration rate also significantly decreased due to compaction of wetland soil. A runoff coefficient was increased due to the low infiltration rate after 2005. A T-N, TSS and Chl.a removal rate was maintained constantly. However, the T-P removal rate was slightly decreased along to wetland operation because low DO concentration could increase elution of phosphorus from sediment. After constructing open water, the T-P removal rate was increased. This is because open water could accelerate the reaearation process. Consequently, over three years of vegetation development could be helpful for wetland performance. In addition, DO concentration is important factor to maintain the T-P treatment.

• Journal of Ecology and Environment
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• v.38 no.2
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• pp.271-279
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• 2015

After the reversion of Okinawa (Ryukyu Islands) to Japan in 1972, extensive urban and agricultural development resulted in a significant increase in sediment discharge to coastal waters. The release of sediment has caused the degradation of freshwater and coastal ecosystems and biodiversity. A consideration for catchment-to-reef continua, as well as agricultural (socioeconomic) factors is necessary to establish proper land-based management plans for the conservation of the island environment. We have set up a framework to integrate biophysics and socioeconomics: 1) setting a conservation target and threshold, 2) identifying the sources and processes, and 3) examining cost-effectiveness and management priorities. The framework may be applicable to other tropical and subtropical islands with similar characteristics.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.99-99
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• 2011

최근에 미국에서 출범한 수질 교환 법은 수질기준을 혁신적인 접근방법으로 만족시키는 법이다. 이 법안은 수질기준을 초과하지 않는 조건에서 한 유역 안 다른 지점들의 점 오염과 비점오염 배출의 교환을 허용한다. 이 법안을 적용하기 위한 방법을 도출하기 위하여 많은 시험 프로그램을 운영하고 있지만 여전히 실제 교환은 상대적으로 적게 이루어지고 있다. 또한 하천내의 비 점오염량의 불확실성으로 인하여 교환 지점을 선정하고 적용하는 데에 큰 어려움이 있다. Hydrological Simulation Program-Fortran (HSPF)은 Soil and Water Assessement Tool (SWAT)과 함께 미국 하천 모델링에 많이 쓰이는 유역 모델로써 특히 HSPF는 각각의 토지 피복도의 퍼센트 투수량을 지정함으로써 도시지역의 유출량을 시뮬레이션 하는데 강점이 있다. 미국 중서부 미조리 주의 퍼시픽시를 포함하고 있는 Brush Creek 유역을 선택하여 퍼시픽시의 도시화 증가로 인한 Brush Creek 유역의 상류와 하류지역의 유출량 및 Sediment 변화를 예측하여 수질관리법을 적용하는 방법을 연구하였다. 이 연구의 특징은 원격탐사 이미지 (QuickBird)로 구현한 최근의 토지 이용을 미래의 도시지역으로 전환한 토지이용도를 사용함으로서 특정 유역을 가장 정확하게 이해하는 시뮬레이션을 가능하도록 한다는 점이다. 각각의 토지이용에서 도시화가 3가지의 강도를 가지고 진행된다는 시나리오를 이용하여 모델링을 하였고 이로 인해 계산된 유출량과 Sediment 양을 이용하여 각각의 토지이용 변화 별 수질 교환단위를 도출 하였다.

• The Journal of Engineering Geology
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• v.17 no.4
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• pp.615-621
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• 2007

Seismic refraction survey which is assumed to be effective for investigating of the amount of bed sediment was applied to two sites having different soil types. The ten lines of seismic surveys were carried out in the areas of the levee near the Wolchon Bridge, Yongin and the Damam levee, Yecheon. At the same time, two borehole data were obtained to be used in classifying geological formations on the inverted seismic sections. As the results of interpolating the depths of geological formations and the surface elevation values, it is possible to estimate the volume of the bed sediments at $24,000m^3\;and\;56,000m^3$ in Yongin and Yecheon, respectively.