• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.1
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• pp.73-79
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• 2009

The hydraulic conductivity of porous media is the most important property in soil characteristics. The hydraulic conductivity is determined by outdoor and indoor methods. Indoor methods normally use soil columns for flow test. Assumption of the column test is that fluid one-dimensionally flows through the column. However, fluids may flow toward the wall of the column, resulting in "boundary flow". This study investigated the effect of boundary flow on the hydraulic conductivity by using a permeameter excluding boundary flow. The results showed that the hydraulic conductivity excluding boundary flow was much smaller than the hydraulic conductivity employing the conventional determination method. This study also investigated the effects of particle size and surfactant on the hydraulic conductivity. As the particle size increased, the hydraulic conductivity was increased. The hydraulic conductivity was reduced by increasing surfactant concentration. The result showed that the viscosity of fluid significantly affected the determination of hydraulic conductivity.

• Journal of Korea Water Resources Association
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• v.41 no.6
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• pp.565-574
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• 2008

Fire-enhanced soil hydrophobicity often increases runoff and erosion in the mountain hillslope following severe wildfires. Estimation techniques for WEPP's parameters were studied in burnt mountain slopes. In burnt mountain slopes, the model over-predicted runoff in the small runoff and under-predicted runoff in the great runoff, and in the lower sediment runoff it had a tendency to over-predict soil loss. The effective hydraulic conductivity was most sensitive in the WEPP's runoff and its sediment runoff was mainly effected by the effective hydraulic conductivity, initial saturation, rill erodibility, and interrill erodibility. To improve the applicability of the WEPP, the adjustment coefficient of effective hydraulic conductivity was defined for runoff and the adjustment coefficient of rill erodibility and interrill erodibility was presented for sediment runoff. The adjustment coefficient of effective hydraulic conductivity in wildfire mountain slopes increased with maximum rainfall intensity of single storm and the vegetation height index. The adjustment coefficients of rill erodibility depended on soil components of size distribution curve and total rainfall depths in single storm. The adjustment coefficients of interrill erodibility decreased with increases of maximum rainfall intensity and vegetation height index. These results may be used in the application of WEPP model for wildfire mountain slopes.

• Korean Journal of Soil Science and Fertilizer
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• v.3 no.1
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• pp.29-34
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• 1970

This experiment was conducted to investigate the influence of amounts of lime dressed on the growth of rice by the treatment of percolation and nonpercolation in the acid sulphate soil. And also analysis of soil chemical components after treatment was carried out. The results obtained were summarized as follows: 1. In the initial stage of growth, number of tillers and plant length showed no distinct differences between the treatments of percolation and nonpercolation, but after August the effect of lime appeared and the percolation treatment was more effective than the nonpercolation. 2. Lime dressing affected good influence on the panicles, grain per panicles and the rate of grain formation, and the treatment of percolation showed better results than nonpercolation. 3. If the yield of rough rice in the control (nonpercolation and lime dressing) was 100, it was 194 in the treatment of nonpercolation 12me/100gr of lime dressed, 268 in the treatment of percolation-4me/100gr of lime and 315 in the 8me/100gr-percolation. 4. Lime dressing affected good influence on the control of Helminthosporium leaf spots. 5. In the case of lime dressing, amounts of available phosphate and soluble silicon dioxide were increased, but ferrous ion ($Fe^{{+}{+}}$) were decreased.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.275-278
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• 2003

지하터널과 같은 대규모 지하구조물 건설시 구조물의 안정성을 확보하고 시공성 등의 실시 설계를 위해서는 그 지역의 수리적 매개변수를 파악하는 것이 필수적이다. 부산광역시 북서부에 위치한 금정산 화강암지역의 수리상수를 산출하기 위하여 야외시험과 실내시험을 수행하였으며, 각각의 결과를 서로 비교 분석하였다. 야외에서는 6개의 시추공에서 수압시험을 수행하여 심도 구간별 수리전도도를 구하였고, 실내시험에서는 시추코아를 이용하여 절리투수시험을 실시하여 수리전도를 산출하였다. 수압시험에 의해 산정된 수리전도도는 2.28E-10 m/sec∼1.49E-06 m/sec 이며, 절리투수시험에 의해 산정된 수리전도도는 1.16E-11 m/sec∼3.26E-05 m/sec이다.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1346-1350
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• 2009

SWAT 모형에서는 중간유출, 침루, 토양 증발, 식물에 의한 증산 등의 수문과정을 모사하기 위해서 토양 수대를 토양의 물리적 특성에 따라 몇 개의 층으로 구분하고, 각 층별로 순차적으로 각 성분량을 계산한다. 이 때 지표유출로 인한 영양물질 이송이 기작되는 영역을 설정하기 위해서 사용자가 입력한 첫 번째 토양층을 강제적으로 둘로 구분하여 상부 10mm의 새로운 토양층이 자동 생성되도록 알고리즘화되어 있다. 그러나, 동일한 토양 특성을 가진 층을 임의적으로 둘로 구분하는 것은 토양 물리적 관점에서 보면 적절하지 않으며, 또한 생성된 매우 얇은 상부 10 mm 토양층으로 인해서 포장용수량을 초과하는 과잉수가 커서 경사가 급한 유역이나 토양층의 투수성이 매우 큰 지역에 모형을 적용할 경우에는 중간유출량이 비현실적으로 크게 계산되는 문제를 수반한다. 따라서 본 연구에서는 중간유출이 크게 계산되는 문제점을 해결하고 토양층내의 수분 거동을 보다 현실적으로 모사하기 위해서 합체-분리 (combining-partitioning) 방식의 토양층 구조화 기법을 고안하고 SWAT의 지표하 유출 계산 모듈에 새롭게 추가하였다. 모형 개선이 수문 및 수질 성분 모의에 미치는 영향을 평가하기 위해서 충주댐 상류유역을 대상으로 모델링을 수행하고 상대비교를 한 결과, 토양수분, 중간 및 지하수유출, 인 순환에 미치는 영향이 가장 큰 것으로 분석되었다.

• The Journal of Engineering Geology
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• v.33 no.3
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• pp.371-388
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• 2023

A stratum with a complex composition and a distributed low-permeability soil layer is difficult to remediate quickly because the soil remediation does not proceed easily. For efficient purification, the permeability should be improved and the soil remediation agent (H₂O₂) should be injected into the contaminated section to make sufficient contact with the TPH (Total petroleum hydrocarbons). This study analyzed a method for crack formation and effective delivery of the soil remediation agent based on pneumatic fracturing, plasma blasting, and vacuum suction (the PPV method) and compared its improvement effect relative to chemical oxidation. A demonstration test confirmed the effective delivery of the soil remediation agent to a site contaminated with TPH. The injection amount and injection time were monitored to calculate the delivery characteristics and the range of influence, and electrical resistivity surveying qualitatively confirmed changes in the underground environment. Permeability tests also evaluated and compared the permeability changes for each method. The amount of soil remediation agent injected was increased by about 4.74 to 7.48 times in the experimental group (PPV method) compared with the control group (chemical oxidation); the PPV method allowed injection rates per unit time (L/min) about 5.00 to 7.54 times quicker than the control method. Electrical resistivity measurements assessed that in the PPV method, the diffusion of H₂O₂2 and other fluids to the surface soil layer reduced the low resistivity change ratio: the horizontal change ratio between the injection well and the extraction well decreased the resistivity by about 1.12 to 2.38 times. Quantitative evaluation of hydraulic conductivity at the end of the test found that the control group had 21.1% of the original hydraulic conductivity and the experimental group retained 81.3% of the initial value, close to the initial permeability coefficient. Calculated radii of influence based on the survey results showed that the results of the PPV method were improved by 220% on average compared with those of the control group.

• The Korean Journal of Ecology
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• v.28 no.5
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• pp.335-345
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• 2005

A study on changes on the distribution of vascular hydrophytes and the growth pattern of Schenoplectus triqueter (Scirpus triqueter) was undertaken at the Nakdong River estuary from 2002 to 2004. The change was due to physical alteration of the estuary for the past 25 years. These plant species are the major food sources for winter waterfowl. A total of 32 species of vascular hydrophytes from 17 families were found in the West Nakdong River (freshwater), the main channel of Nakdong River (freshwater) and the Nakdong River Estuary (brackish water). After the construction of the barrage on the estuary in 1987, the number of hydrophytes has remarkably increased to 17 species (5 species in 1985) in the main channel of the River. In particular, a community of Eurale ferox was found at the backwater wetland of the Daejeo side of the main channel. The introduced species of Eichhornia crassipes and Pistia stratiotes that were epidemic in 2001 at West Nakdong River was not found any more. The other species such as Nymphoides indica, Myriophyllum spicatum, Ruppia spp. were rediscovered. The large area (about 1,300ha) of Zostera spp. was the main sources of food for swans, but disappeared because of direct and indirect impacts of reclamation in the River estuary. Currently, there remains a small patch of Zostera spp. and about 250ha of S. triqueter. Schenoplectus triqueter grew mostly between April-September and tuber formed, between September-October. The growth of S. triqueter up to $60\sim80cm$ in length was observed in 5 sites out of the 7 sites in brackish area. Tubers of S. triqueter were eaten by waterfowls such as swans as winter food. In five sites, tubers took $44\sim57%$ of total biomass in October. Tubers were found in deep layers; $5\sim15cm$ (9%), $15\sim25cm$ (28%), $25\sim40cm$ (55%), below 40cm $(6\sim7%)$. The distribution of vascular hydrophytes has remarkably changed in the Nakdong River Estuary due to the reclamation of the area. In order to determine the extent of changes of the distribution of these plants and the carrying capacity of the area for waterfowl, an intensive research is urgently needed.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.353-353
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• 2023

기후변화에 대응하는 도시유출 저감과 열섬효과를 방지하기 위해 투수블럭 시공이 증가 추세 있으나, 투수블럭과 하부 도로포장체에 대한 강우모사 시험시 토양함수율 설정기준을 정립할 필요가 있다. 유역 혹은 시험체의 유출량 예측에는 토지 이용에 따라 미국자연자원보호청(Natural Resources Conservation Service, NRCS)의 SCS 유효우량 산정 방법을 통해 CN을 활용할 수 있으며, 이때 유역 혹은 시험체의 선행강우일수에 따라 유출량 결과가 큰 차이가 발생한다. 연구를 위해 시험실이 위치하고 있는 부산시와 양산시 무강우 일수(10년, 2012~2021)를 홍수기, 비홍수기 각각 분석한 결과에 따라, 투수블록 포장체의 CN 산정을 위해 자연강우 이후 시험시 AMC조건을 따르며, 무강우일수 5일 이내에는 비성수기 12.7~27.94mm, 성수기 35.56~53.34mm의 평균강우 20.32mm, 44.45mm에 해당하는 체적의 실험수를 사전에 살수한 후 강우모의시험을 진행한다. 사전살수를 통해 하부기층 토양을 AMC-II 기준에 맞추고, 강우모의 시험을 통해 CN(II) 산정한다. 동일기준에서 진행된 시험 결과, 일정한 유출을 확인하였으며, 적용에 일관성을 유지할 수 있었다. 따라서 토양종류와 토양함수조건에 의거 투수블록 포장 시험체의 CN을 산정을 통해, 도시홍수 유출모형에 적용할 수 있다. 53.34mm 이상의 자연강우시 모니터링을 통한 CN(III)을 산정하여CN(II)로 환산하여 경제적이고 합리적인 유출량을 산정한다.

• Journal of Korea Water Resources Association
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• v.32 no.6
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• pp.637-647
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• 1999

This study investigated the applicability of generalized TOPMODEL approach which introduces the power law of decreasing transimissivity with depth instead of the traditional exponential decreasing function. The 50m digital elevation model(DEM) of Dongkog subwatershed at Wichon Test Watershed was used to perform runoff simulation. Random number generation algorithm was integrated into the calibration process for the reliable of model performance. General power law version of TOPMODEL with exponent 2 and 3 showed higher simulation efficiency than other the approaches. This results from the fact that the power law models with exponent 2 and 3 can represent the soil characteristics of study area better than other models.

• Journal of Korea Water Resources Association
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• v.47 no.1
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• pp.49-62
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• 2014

As the Urban area grows and more land is developed both within the city and in surrounding areas, hydrologic functions of the natural water cycle are altered. Urbanization creates impervious areas that negatively impact stormwater runoff characteristics. these changes to the natural hydrologic cycle result in the increased flooding, decreased groundwater recharge, increased urban heat island effects. Finally, the land use and other activities result in accumulation and washoff of pollutants from surface, resulting in water quality degradation. Therefore, in this study, evaluating and quantitative analysis of the percolation effect through infiltration experiment of permeable pavement, which is one of the ways that can reduce the problem of the dry stream. Also the SWMM model is used to study the effect of the hydrologic cycle for permeable pavement block contribution.