• Economic and Environmental Geology
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• v.29 no.1
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• pp.57-63
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• 1996

The Dalsung copper-tungsten mine in the Taegu area, Korea was closed in 1975 and may be the sources of the heavy metal contamination in the tributary system and soil-plant system due to the mine drainage derived from the mine wastes and tailings. To examine the degree and extent of heavy metal contamination in the vicinity of Dalsung mine area, stream water and soil samples were taken and analyzed for heavy metals by ICP-AES and AAS. Highly contaminated soils are found near the Lower Tunnel No.0 ranging up to $1760{\mu}g/g$ As, $2060{\mu}g/g$ Cu, $1120{\mu}g/g$ Pb and 346 ${\mu}g/g$ Zn. From the results of the sequential extraction methods for the metal speciation, the heavy metals in soils may be derived from soil parent materials and acid mine drainage. With the processes for the heavy metal removal, most of the heavy metal ions in the acid mine drainage are removed by being exchanged with Ca ions held by the bentonite, hydroxyapatite and calcium hydoxide.

• Tunnel and Underground Space
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• v.24 no.5
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• pp.335-343
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• 2014

Room-and-pillar mining method is one of the most popular underground mining method in the world. If the room-and-pillar mining method is able to be adopted in civil works, it would be highly probable to reduce underground construction costs and to expand a underground structure in use. Therefore, this study aims to analyze the design procedure of unsupported rock pillars which are indispensable to ensure the stability of a room-and-pillar underground structure. Parametric studies on their key design parameters are also carried out for 125 different kinds of design conditions. From the study, the width of a rock pillar is found to show a linear relationship with its corresponding safety factor. The safety factor of a unsupported rock pillar decreased drastically like a negative exponential function as the ratio of room width to pillar width increases in the same rock strength condition. Based on the parametric studies, a design chart to simply evaluate the geometric design parameters of a unsupported rock pillar satisfying a design safety factor is also proposed in this study.

• Korean Journal of Ecology and Environment
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• v.43 no.2
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• pp.232-241
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• 2010

Epilithic diatom communities and water quality were monitored to evaluate the ecological impact of the inflow of Wonju-stream passing through the urban area in the Seom River Watershed. We selected the 14 sampling stations (5 main stream sites and 9 tributary sites), and collected diatom and water samples between October 2007 and September 2008, on the seasonal basis. The results indicate that most water quality parameters showed the site-specific patterns over the study, except for water temperature and dissolved oxygen. The levels of water quality parameters were highest at the site of Wonju stream, whereas the lowest in the upstream sites, and intermediate or gradually decreased in the downstream sites of the Seom river. One species, Achnanthes convergens, showed the highest biomass and frequency over the sites, while three saprophilous species-Navicula goeppertiana, Navicula subminuscula, Nitzschia palea were appeared only in Wonju Stream and other polluted sites. According to trophic diatom index (TDI) values, which were highly correlated with nutrients and EC, the study sites were classified into three classes: upstream and tributary (Class A and B), Wonju Stream (Class D), and mixed zone and downstream (Class C). A cluster analysis supported the result of TDI classification. Therefore, Wonju-stream located in populated urban area exerted the adverse ecological effects on the epilithic diatom community and water quality of the lower Seom River System, although its severity gradually decreased downstream.

• Journal of Korea Water Resources Association
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• v.37 no.7
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• pp.599-612
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• 2004

The continuous long-term rainfall-runoff simulation model SWAT has the advantage of being able to account for various land use, however, SWAT lacks the capability of simulating the drainage characteristics of urban area. On the other hand, SWMM, which is the most popular model for runoff analysis of urban watershed, has the advantage of being capable of considering surface and drainage characteristics in urban area, but SWMM cannot easily account for land use other than urban area within a watershed. In this study, SWAT-SWMM model, which builds on the strengths of SWAT and SWMM, has been applied to the Osan River Watershed which is a tributary watershed to the Gyung-Ahn River. From the application, the results from coupled SWAT-SWMM model has been compared to the ones from SWAT for each hydrologic component such as evapotranspiration, surface runoff, groundwater flow, and watershed and channel discharge, and the runoff characteristics of two models for each hydrologic component has been discussed.

• Journal of the Korean Institute of Landscape Architecture
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• v.18 no.3 s.39
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• pp.57-70
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• 1990

This study is on system building and model case study to establish a new framework of "The Wild and Scenic Rivers System" and to apply this to Korean rivers. The Wild and Scenic Rivers System of the U. S. , which had become law in 1968 for establishing wild scenic and recreational river areas, was investigated. The techniques of two American case studies about the National Wild and Scenic Rivers System designation were investigated and synthesized, and study process was adjusted to Korean river system. Additionally, pilot study was carried out by the method and results were as follows : 1) In the American Wild and Scenic Rivers System, each river was evaluated based on eligibility criteria for designation, such as remarkable scenic, recreational, fish and wildlife, cultural or other ecological values. Segmented river areas were classified into three or four grades and management plans were prepared accordingly. 2) The management of rivers in Korea has emphasized on the flood control and water resources management up to the present, and now takes a growing interest in water quality. But it has been concerned very little with wild and scenic resources conservation of river corridors. It is strongly recommended to build Wild and Scenic Rivers System in Korea for rational management and conservation of the valuable natural resource. 3) Suggested evaluation criteria for the Korean Wild and Scenic Rivers System were wildness, wildlife and plants, hydrology, scenic quality, and historical and cultural resources. The river areas may be graded into four : Positive conservation area(I), Negative conservation area(II), Negative development area(III), Positive development area(IV). Management guidelines were proposed for each grade. 4) To test the applicability of the approach, one of the major tributary of the Han-River was selected for pilot study. The result showed that the evaluation and grading system worked well. Finally, it is recommended to incorporate the Wild and Scenic Rivers System into Korean national park system, and to amend the Korean National Park Act to enable this.

• Journal of Korean Society on Water Environment
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• v.39 no.6
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• pp.439-450
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• 2023

The Yeongsan River, a major water resource for Jeollanam-do, that is adjacent to industrial complexes and agricultural areas, is exposed to water pollution. Therefore, it is necessary to investigate the impact of water pollution incidences and prepare response systems for river environment safety for other water resources in the future. Environmental Fluid Dynamics Code (EFDC) was applied to the mainstream of the Yeongsan River where residential, commercial, and agricultural areas are located to analyze the behavior of pollutants conducting the scenario analysis. Considering the pollutants that affected the study area, two pollutants, oil and benzene, with different physical and chemical characteristics were selected for the analysis. As a result of comparing the actual and simulated values of the water elevation, temperature, and flow rate, it was confirmed that the model adequately reproduced the hydraulic characteristics of the Yeongsan River. The oil flow dynamics showed that an increase in flow rate led to reduction in the maximum height of the slick. Notably, the behavior of the oil was predominantly influenced by the wind conditions. In the case of benzene, lower flow scenarios exhibited decreased arrival times and residence times accompanied by an elevation in the maximum concentration levels. From the results of pollutant behavior in the study area, it is feasible to utilize the section of tributary confluence for collection and the weir area for dilution. This study enhances the understanding of the pollutant's behavior with different characteristics and develops effective control systems tailored to the physicochemical attributes of pollutants.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.2
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• pp.170-176
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• 1998

Nitrogen and phosphorus loads from an agricultural watershed of the Yulmun-chon tributary in the Buk-Han River Basin were quantified based on total amounts of water stream flow. The water quality and soil loss were estimated. Levels of the stream were recorded automatically using the water level meter. The flow velocities, along with the cross-sectional areas of the riverbed, were measured to estimate total amounts of water flow at three monitoring sites in this tributary. Water samples were collected at nine sites with two weeks interval from May to August and analyzed for the water quality parameters. Amounts of soil loss were estimated by the USLE. The size of the Yulmunchon watershed was 3,210 ha, of which paddy and upland soil areas were composed about 41%. The total amounts of soil loss from the watershed areas were estimated to be $13,273Mg\;year^{-1}$, showing 53%, 46% and 0.7% of the soil loss ratio from upland, forest, and paddy areas, respectively. Electrical conductivities and Nitrogen concentrations of the stream water were higher in the lower watershed area than in the upper area. Increments of N were higher for $NO_3-N$ than $NH_4-N$. Nitrate nitrogen was the major N form to pollute the water due to the agricultural activity. Total runoff was about 72% of the total precipitation in the watershed. The maximum loads of T-N and T-P due to the runoff were estimated to be 1,500 and $5kg\;day^{-1}$, respectively. Concentrations of $NO_3-N$ and $NH_4-N$ in the runoff were 13.5 and 1.8 times higher than those in precipitation. The N loads were mainly from soil loss, application of fertilizer, and livestock wastes, which were 52% of total N load. Results demonstrated that reduction of fertilizer use and the soil loss would be essential for water quality protection of the agricultural watershed.

• Journal of Korean Society on Water Environment
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• v.20 no.2
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• pp.151-156
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• 2004

A decision support system, Watershed Analysis Risk Management Framework(WARMF), was applied to the Kyungan Stream watershed, a tributary of Lake Paldang, for calculation of total maximum daily loads(TMDL). The WARMF system was developed by Systech Engineering, USA, and has been successfully used in several watersheds, for TMDL studies. The study area was divided into 14 sub-basins, based on digital elevation model(DEM). The integrated watershed and stream model of WARMF was validated by flow and BOD data measured during the year of 1999. There were reasonable agreements between model results and field data, both in water flow and BOD. The validated Kyungan WARMF was extensively utilized to study the quantitative relationship between waste loads and receiving water quality. Based on TMDL guideline at Paldang Lake and Kyungan Stream, the water quality criterion were set to be 3.0mg/L, 3.5mg/L, and 4.0mg/L at the watershed outlet. The allowable waste loads of BOD, both from point and non-point sources, were determined at each water quality criterion. From this study, it was concluded that the WARMF provided several advantages over the conventional application of watershed and stream models for TMDL study, such as time variable simulations, multiple possible soutions, and reduction loads for goal water quality, etc.

• Economic and Environmental Geology
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• v.28 no.3
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• pp.213-220
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• 1995

Geochemistry of stream water and sediment collected in the vicinity of the Donghae coal mine in the Samchuk coalfied were investigated in order to evaluate the environmental impacts of acid mine drainage. The pH of stream water ranges from 2.85(at 2 km away from the mine) to 7.92(at uncontaminated tributary). The main cation and anion species in the upper stream are $Ca^{2+}$ and $SO_{4}{^2-}$, respectively. The level of pH and the amount of $HCO^{3-}$ in stream water increase to the downstream and where uncontaminated small tributaries are joining, and in the area covered with limestone. From the results of thermodynamic calculation, the main forms of iron in stream water are estimated as $Fe^{2+}$ and $FeSO_{4}{^0}$, and most of them could be precipitated as FeO(OH) with increase of pH. The white precipitates in stream sediments particularly found around the coal mine are proved to be $Al(OH)_3$ by XRD and XRF analysis. As a result of investigation for seasonal variation of AMD, the level of pH decreased and conductivity increased in dry season.

• Journal of Environmental Science International
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• v.16 no.5
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• pp.649-655
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• 2007

This study was focused on estimating instream flow, and its optimal alternative for securing the required total amount of instream flow was also researched in order to restore ecosystems and riverine aesthetics of the Mugeo Stream. the first tributary of the Taewha River flowing through the center of Ulsan. In this study the hydraulic and hydrologic conditions and water quality were investigated at specific channel reaches and representative stations of the Mugeo Stream to determine a proper estimate of instream flow. And riverine functions, such as the minimum flow, water duality conservation, fish habitat, and recreation, were considered to restore the environmental functions of the stream, As a result, the total amount of $11,500m^3/day$ was set as the target instream flow for the Mugeo Stream. It was chosen as the optimal alternative for securing the total external supply of $10,000m^3/day$ which have to be transfered from the riverbed flow diverted through the Taewha Main river at upstream of Samho bridge. The water duality throughout the Mugeo Stream channels will be improved considerably to 3-4 mg/l of BOD standard if the target instream flow is supplied and sewage is intercepted by the sanitary sewage system.