• Title/Summary/Keyword: Soil-water characteristics

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The Distribution Characteristics of Heavy Metals in the Water, Sediment and Soil along the West Nakdong River (서낙동강 유역의 강물, 저토 및 토양의 중금속 분포 특성)

  • Park, Heung-Jai;Park, Jong-Kil;Park, Won-Su
    • Journal of Environmental Science International
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    • v.3 no.4
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    • pp.409-416
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    • 1994
  • This study was Performed to evaluate the contents of heavy metals in water, sediment and soil of the 7 different sampling points along the West Nakdong river, The results were as follows: the concentrations of Zn, p, Pb, Cd, Mn, Cu and As in the sediment were 197.48, 551.85, 67.01, 2.54, 491.39, 42.95 and 10.52ppm, respectively. The concentrations of Zn, p, Pb, Cd, Mn, Cu and As in the soil was 83.32, 482.89, 17.15, 1.02, 226.02, 26.15 and 7.29ppm, respectively. The concentration ratios of heavy metals In the water to the sediment were 593 - 12700 (Cd >> Cu > Zn > Mn > As > Pb) and that of the water to the soil were 152 - 5100 (Cu > Cd > Zn > Mn > As >Pb). The correlation coefficients of Cu and Pb weve high among the water, sediment and soil. Because the accumulation amounts of heavy metal in the sediment were high, the concentration of heavy metals in the sediment was higher than in soil. The correlation coefficient of heavy metals among water, sediment and soil was high (0.79 - 0.95). Key Words Distribution Characteristics, heavy metals, West Nakdong River.

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Ecohydrologic Analysis on Soil Water and Plant Water Stress : Focus on Derivation and Application of Stochastic Model (토양수분과 식생의 물 압박에 대한 생태수문학적 해석 : 추계학적 모형의 유도와 적용을 중심으로)

  • Han, Suhee;Kim, Sangdan
    • Journal of Korean Society on Water Environment
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    • v.24 no.1
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    • pp.99-106
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    • 2008
  • With globally increasing interests in climate-soil-vegetation system, a new stochastic model of soil water and plant water stress is derived for better understanding of the soil water and plant water stress dynamics and their role in water-controlled ecosystem. The steady-state assumption is used for simplifying the equations. The derived model is simple yet realistic that it can account for the essential features of the system. The model represents the general characteristics of rainfall, soil, and vegetation; i.e. the soil moisture constitutes the decrease form of the steady-state and the plant water stress becomes increasing with the steady state when the rainfall is decreased. With this model, further deep study for the effects of soil water and plant water stress on the system will be accomplished.

Probabilistic Solution to Stochastic Soil Water Balance Equation using Cumulant Expansion Theory (Cumulant 급수이론을 이용한 추계학적 토양 물수지 방정식의 확률 해)

  • Han, Suhee;Kim, Sangdan
    • Journal of Korean Society on Water Environment
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    • v.25 no.1
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    • pp.112-119
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    • 2009
  • Based on the study of soil water dynamics, this study is to suggest an advanced stochastic soil water model for future study for drought application. One distinguishable remark of this study is the derivation of soil water dynamic controling equation for 3-stage loss functions in order to understand the temporal behaviour of soil water with reaction to the precipitation. In terms of modeling, a model with rather simpler structure can be applied to regenerate the key characteristics of soil water behavior, and especially the probabilistic solution of the derived soil water dynamic equation can be helpful to provide better and clearer understanding of soil water behavior. Moreover, this study will be the future cornerstone of applying to more realistic phenomenon such as drought management.

Application of Analysis Models on Soil Water Retention Characteristics in Anthropogenic Soil (인위적으로 변경된 토양에서의 수분보유특성 해석 모형의 적용)

  • Hur, Seung-Oh;Jeon, Sang-Ho;Han, Kyung-Hwa;Jo, Hee-Rae;Sonn, Yeon-Kyu;Ha, Sang-Keun;Kim, Jeong-Gyu;Kim, Nam-Won
    • Korean Journal of Soil Science and Fertilizer
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    • v.43 no.6
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    • pp.823-827
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    • 2010
  • This study was conducted to assess the propriety of models for soil water characteristics estimation in anthropogenic soil through the measurement of soil water content and soil water matric potential. Soil profile was characterized with four different soil layers. Soil texture was loamy sand for the first soil layer (from soil surface to 30 cm soil depth), sand for the second (30~70 cm soil depth) and the third soil layers (70~120 cm soil depth), and sandy loam for the fourth soil layer (120 cm < soil depth). Soil water retention curve (SWRC), the relation between soil water content and soil water matric potential, took a similar trend between different layers except the layer of below 120 cm soil depth. The estimation of SWRC and air entry value was better in van Genuchten model by analytical method than in Brooks-Corey model with power function. Therefore, it could be concluded that van Genuchten model is more desirable than Brook-Corey model for estimating soil water characteristics of anthropogenic soil accumulated with saprolite.

Estimation Model for Simplification and Validation of Soil Water Characteristics Curve on Volcanic Ash Soil in Subtropical Area in Korea (난지권 화산회토양의 토색별 토양수분 특성곡선 및 단일화 추정모형)

  • Hur, Seung-Oh;Moon, Kyung-Hwan;Jung, Kang-Ho;Ha, Sang-Keun;Song, Kwan-Cheol;Lim, Han-Cheol;Kim, Geong-Gyu
    • Korean Journal of Soil Science and Fertilizer
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    • v.39 no.6
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    • pp.329-333
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    • 2006
  • Most of volcanic ash soils in South Korea are distributed in Jeju province which is an island placed on southern part of Korea and has steep slope mountain area. There are many soils containing high contents of organic matter (OM) derived from volcanic ash in Jejudo, also. Therefore, irrigation and drainage in volcanic ash soil different with general soil which has low OM content have to be applied with another management way, but studies searching appropriate methods for them are set on insufficient situation because the area of volcanic ash soil in South Korea is only 1.3% (130,000ha). This study was conducted for analysis of soil water content and irrigation quantity appropriate for crops cultivated in volcanic ash soil with high OM content. Although soils with different soil color have the same soil texture, soil water characteristics curve by soil color showed the difference of water retention capability by OM content. But, this characteristics classified with soil color could be unified by scaling technique with similitude analysis method which get dimensionless water content using a present water content, a residual water content and saturated water content (or water content at 10kPa). A relation of gravimetric soil water content (GSWC) and dimensionless water content by the results showed a form of power function. The dimensionless water content (DWC) express a relative saturation degree of present water content. This was also expressed by van Genuchten model which describe the relation between relative saturation degrees and matric potentials. These results on soil water characteristics curve (SWCC) of volcanic ash soil will be the basic of irrigation plan in area having high organic contents into soil.

Assessment of Soil Characteristics on External Corrosion of Water Pipes (토양특성이 상수도관의 외부부식에 미치는 영향 평가)

  • Bae, Chul-Ho;Kim, Ju-Hwan;Park, Sang-Young;Kim, Jeong-Hyun;Hong, Seong-Ho;Lee, Kyoung-Jae
    • Journal of Korean Society of Water and Wastewater
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    • v.20 no.5
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    • pp.737-745
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    • 2006
  • The goal of this study is to present an external pit corrosion rate($p_{ecr}$) model with considering both the age of pipe and the soil characteristics. The correlation of nonlinear exponential model among conventional empirical models was a little higher than other empirical models in the prediction of $p_{ecr}$ according to the age of pipe. However, there has been a limit to predict Peer with the model by using only a pipe age since installation as a variable. The soil analysis results from sixty nine samples showed that all of the samples were non corrosive in the assessment of ANSI/AWWA scoring system. The correlation of soil corrosion factors and $p_{ecr}$ was also low. The application result of linear and nonlinear regression models that soil characteristics only showed a low correlation with $p_{ecr}$ Proposed nonlinear regression model in this study, with considering both the age of pipe and the soil characteristics, showed a little higher correlation ($R^2=0.46$) than conventional model.

Stability analyses of dual porosity soil slope

  • Satyanaga, Alfrendo;Moon, Sung-Woo;Kim, Jong R.
    • Geomechanics and Engineering
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    • v.28 no.1
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    • pp.77-87
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    • 2022
  • Many geotechnical analyses require the investigation of water flow within partially saturated soil zone to incorporate the effect of climatic conditions. It is widely understood that the hydraulic properties of the partially saturated soil should be included in the transient seepage analyses. However, the characteristics of dual porosity soils with dual-mode water retention curve are normally modelled using single-mode mathematical equation for simplification of the analysis. In reality, the rainwater flow can be affected significantly by the dual-mode hydraulic properties of the soil. This paper presents the variations of safety factor for dual porosity soil slope with dual-mode water retention curve and dual-mode unsaturated permeability. This paper includes the development of the new dual-mode unsaturated permeability to represent the characteristics of soil with the dual-mode water retention curve. The finite element analyses were conducted to examine the role of dual-mode water retention curve and dual-mode unsaturated permeability on the variations of safety factor under rainfall loading. The results indicate that the safety factor variations of dual porosity soil slope modelled using the dual-mode water retention curve and the unsaturated permeability equation are lower than those of dual porosity slope modelled using single-mode water retention curve and unsaturated permeability equations.

Slaking and Particle-Separation Characteristics of the Organic Fine Soil in Paddy Fields (전답용 유기질 세립토의 슬레이킹 내구성 및 분쇄 특성)

  • Cho, Sung-Min
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.5 no.3
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    • pp.1-8
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    • 2002
  • Clayey paddy soils should be mixed with other good coarse soils to be used as a material for the lining, or, embankment. However, it has been difficult to separate soil particles from each other because of the internal cohesion in the soil gradation(separation) characteristics of the fine soil were investigated by various laboratory tests including the slaking durability test. Degradation rate of the soil were dependent upon the clay content and the initial water content before the submergence. The amount of degradations decreased as initial water content increased with exponential functions. The dried specimens separated into the particles after 24 hours of the submergence and specimens which water contents were less than 10% also separated into the particles after 2, or 3 days of the submergence. Compaction curves and the unconfined strength were not varied before and after the submergence. However, unconfined strength decreased as water content increased.

An Experimental Study on Frost Heaving Characteristics of Soil Stabilized with the Additives (안정처리토의 동상특성에 관한 실험적 연구)

  • Kim, Jae-Young;Ju, Jae-Woo;You, Byung-Ok;Yang, Sung-Kee
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2003.10a
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    • pp.215-218
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    • 2003
  • In order to study the frost heaving characteristics of soil stabilitized with a quick lime, a cement and a briquette ash, frost heaving tests were performed with 2 kinds of soil sampled at Chonbuk-Do area. Frost heaving of no-stabilizing soil compacted with water content greater than optimum water content was increased as the frost period was increased but in case of samples with water content smaller than optimum water content, the frost period gave no affect about increase and decrease of the frost heaving. Both frost heaving of stabilizing and no-stabilizing soil with water content greater than optimum water content was decreased with the increase of the repetition number of freezing and thawing. There was no increase or decrease of frost heaving in the frost heaving test after 5 times of freezing and thawing.

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A Study on the Binding Characteristics of $\beta$-Cyclodextrin with Benzene and Its Application on the Bioremediation ($\beta$-시클로덱스트린($\beta$-Cyclodextrin)의 결합 특성과 벤젠의 생물학적 분해에의 적용에 대한 연구)

  • 최종규;손현석;조경덕
    • Journal of Environmental Health Sciences
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    • v.28 no.5
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    • pp.65-70
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    • 2002
  • Recently, surfactants were frequently used in order to desorb the hydrophobic organic compounds (HOCs) from soil and to enhance the bioavailability. Among them, -cyclodextrin ($\beta$-CD) is one of those. This study was performed to investigate the binding characteristics between benzene and $\beta$-CD and to examine the bioavailability of benzene. First, we investigated binding characteristics between benzene and $\beta$-CD in water and water/soil system. Then, we examined the effect of $\beta$-CD on the biodegradation of benzene in water and water/soil system. Experimental results on the binding characteristics showed that $\beta$-CD resulted in an efficient complex formation with benzene. As -CD concentration increased, the benzene concentration complexed with $\beta$-CD rapidly increased to 30-40% initial benzene added, and reached the equilibrium. We also investigated the effect of $\beta$-CD on the desorption of benzene from soil in the water/soil system. As $\beta$-CD concentration increased, benzene concentration desorbed into water increased up to 90%. How-ever, in its application to biodegradation of benzene in water and water/soil system, the biodegradation rate of benzene did not improved in the presence of $\beta$-CD compared with in the absense of $\beta$-CD. This result indicated that $\beta$-CD was more preferentially used as a carbon source than benzene. Therefore, for remediation of benzene contaminated soils, $\beta$-CD can be used as a surfactant to desert benzene from soil, and then ex-situ chemical treatment can be applied for the remediation.