• Journal of environmental and Sanitary engineering
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• v.24 no.1
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• pp.1-12
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• 2009

The various environmental problems that we face on today are basically about environmental quality. Since early 1960s affluent material was produced because of remarkable economic growth by many cooperations. However, for the lack of environmental policy, environmental pollutions has been serious. The central government should transfer the producing and consuming structure to environmental affinity through the regulations for developing Korea as a model of environmental nation which takes an active part in global environmental programme and in which the environment and economy are well harmonized. Moreover, the central government should take the lead in prevention of environmental pollution through the direct policies such as strengthening the discharge limit or setting up environmental basic institutions by securing budget for conserving environment. This thesis emphasize on the public institution among many environmental basic institutions for environmental anti-pollution project. It will find the problems with running those institutions, and will suggest the preview of improvement. Also, it is necessary to investigate of variation trend for inflow and pollutant loading to environmental infrastructure as increased of the diffusion rate as established and maintenance of sewer system. The purpose of this study is to investigate for inflow and pollutant loading to environmental infrastructure, and also to provide the method of efficiently maintenance and management. The results obtained were summarized as follows; 1. Survey of actual condition on operation and management of environmental infrastructure was evaluated the propriety of treatment process and problem of plant management. 2. Analysis of pollutant loading contribution for river system of environmental infrastructure with data analysis of water quality measuring network. 3. To investigate on case study for efficiently maintenance and management of environmental infrastructure. The result on this study was provide the method of efficiently maintenance and management with survey for establish and repair of sewer system and survey of actual condition on operation and management of environmental infrastructure in the water area of discharge to Geum River System. Application as guideline for establish and management of environmental infrastructure, and management of Geum River System. Also, application for preliminary data for fulfill-assess of total effluent regulation of water pollution.

• Journal of Environmental Science International
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• v.20 no.10
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• pp.1285-1295
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• 2011

In this study, occurrence status of nonpoint pollutants and characteristics of discharge by each nonpoint pollutants were examined through monitoring on nonpoint pollutants caused when raining in vineyard belonging to the agricultural area of various land use patterns. Also, the first flush analysis limited to studies on the existing non-percolation area was applied to percolation area to ascertain availability and criteria of study. Various water quality and sluice of nonpoint pollutants were analyzed, based on which discharge of nonpoint pollutants in agricultural area was ascertained to be influenced greatly by artificial factors such as period, cultivation, management, etc. Meanwhile, the first flush phenomenon at agricultural area was ascertained to occur, and the first flush was quantified through calculation of the first flush ratio. If MFF30 is based, discharge load by each nonpoint pollutants caused when raining was investigated to include 40.8% on the basis of total discharge. In case of SS in pollutants showed the highest first flush phenomenon of 64.8%. Through such a result, calculation possibility of the initial rain criteria was ascertained, and it was determined that reliability-assured criteria were calculated through further monitoring.

• Korean Journal of Remote Sensing
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• v.34 no.2_1
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• pp.203-211
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• 2018

Dam discharge is carried out for the management of rivers and area around rivers due to rainy season or drought. Dam discharge should be based on an accurate understanding of the flow rate that can be accommodated in the river. Therefore, understanding the allowable storage capacity of river is an important factor in the management of the environment around the river. However, the methods using water level meters and images, which are currently used to determine the allowable flow rate of rivers, show limitations in terms of accuracy and efficiency. In order to solve these problems, this paper proposes a method to automatically calculate the allowable storage capacity of river based on the images taken by drone. In the first step, we create a 3D model of the river by using the drone images. This generation process consists of tiepoint extraction, image orientation, and image matching. In the second step, the allowable storage capacity is calculated by cross section analysis of the river using the generated river 3D model and the road and river layers in the target area. In this step, we determine the maximum water level of the river, extract the cross-sectional profile along the river, and use the 3D model to calculate the allowable storage capacity for the area. To prove our method, we used Bukhan river's data and as a result, the allowable storage volume was automatically extracted. It is expected that the proposed method will be useful for real - time management of rivers and surrounding areas and 3D models using drone.

• Journal of Wetlands Research
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• v.14 no.1
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• pp.21-33
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• 2012

The dominant land use at the Seonakdong river watershed is paddy and forest areas and the Seonakdong river stands still. Thus, the water pollution in the Seonakdong river is becoming more serious for the non-point source. In this study, SWAT(Soil and Water Assessment Tool) model was evaluated for simulation of flow and water quality behaviors in Seonakdong river. To perform the calibration and verification of the SWAT model, the measurements of discharge and water quality were performed for the period from 2006 to 2007 at 5 gauging stations in Seonakdong river. The $R^2$ value for discharge and water quality were 0.86 and 0.70 respectively for calibration after the sensitive analysis. The $R^2$ value for discharge and water quality were 0.81 and 0.51 respectively for verification. The simulation results show that BOD value in the river tends to decrease after the opening of gates and the patterns of TN and TP concentrations are similar as that of BOD. The gate operators need to determine how to supply water in drought season for effective water quality improvement. This study shows that the SWAT model, which is capable of simulating hydrologic and water quality behaviors temporarily and spatially at watershed scale, could be used to get the gate operation rule for the water quality management in Seonakdong river.

• Korean Journal of Ecology and Environment
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• v.36 no.3 s.104
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• pp.242-256
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• 2003

This study aimed to determine the relationship between rainfall-discharge patterns and maior aquatic environmental factors in a river-type reservoir. Specifically, daily monitoring was conducted in Paltang Reservoir from January 1999 to December 2001. Observation of the daily changes of the environment factors showed that natural meteorological factors and hydrological factors causing the change of water discharge had a major effect on the aquatic environment. Rainfall was the main source of hydrological changes, with its frequency a possible direct variable governing the range of discharge changes. Rainfall was weak in November${\sim}$May and heavy in June${\sim}$October (heavist in summer). The range of water discharge was greatest during summer (July to September) and lowest during winter (January to February). A principal component analysis (PCA) showed that aquatic environmental factors could be classified into three different types in the pattern of annual variation. First, type I included water temperature, turbidity, water color and organic matter (COD), which increased with increasing water discharge. Second, type ll consisted of DO and pH, which decreased with increasing water discharge. Third, type III included conductivity, alkalinity and chloride ion, which showed middle values with increasing water discharge. Monthly variation of aquatic environments explained by the first two dimensions of the PCA suggests that aquatic environments of Paltang Reservoir may have annual cycle typical of river-type reservoirs depending on hydrological factor such as water discharge.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3B
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• pp.315-321
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• 2008

Recently, in the light of environments and utilization, countermeasures to preserve beaches in coastal area are required without depending on such as jetties and breakwaters. The necessity of integrated sand management including not only coastal sediment but also sediment discharge from hinterland rivers is increased so as to establish long-term counterplan for sediment transport. In this regard, the following subjects are examined in this study; efficient ways for discharged sand to be transported from a river to the neighboring coast, the river terrace occurrence and its growth at the river delta, measures to improve storage efficiency of the discharged sand and measures to prevent the sand resources from being discharged into the deep sea during flooding. In recent, A jetty of 260 m length was constructed at Namdae River mouth in the year of 2005 as a countermeasure against the occurrence of sand-bar at river mouth and its close. In this study, a series of numerical experiments were carried out to investigate the characteristics of sediment transport and morphological change due to the construction of jetty at the entrance of Namdae River mouth. Firstly, The sand discharge from Namdae River is quantified by one-dimensional numerical analysis assuming the mixed sand of three different particle diameters. Then, in order to understand the transport behavior of the sand discharge from river and river mouth phenomena the numerical experiments were then conducted to examine the flow behaviors of river efflux and wind generated circulations in coastal area. And, after establishing the numerical model system, which predicts the sea bed changes obtained from the flux model combining with the wave propagation, wave-induced currents and sediment transport models, the sediment transport in the vicinity of Namdae River mouth is analyzed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.3B
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• pp.169-174
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• 2012

For efficient water management in the Ara River during the flood season, applicability of flood simulation model in the ungaged Gulpo watershed has been tested. In the Gulpo River watershed, fundamental hydrologic data such as water level and flowrates are very limited and selection of the reliable hydrologic parameters are very important for model application. This study tested reliability of parameters estimated using the empirical equation based on the HEC-HMS runoff simulation. Also coupled with HEC-RAS hydraulic routing model, simulated flowrates from HEC-HMS has been compared with the observed water levels collected at the upstream and downstream of the Gyulhyun Weir station during the flood event in 2010. Based on this information, stage-discharge curve has been developed and its reliability has been tested for flood event in 2011.

• Journal of Korean Society on Water Environment
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• v.34 no.5
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• pp.537-547
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• 2018

Sediment discharge by rainfall runoff affects water quality in rivers such as turbid water, eutrophication. In order to solve various problems caused by soil loss, it is important to establish a sediment management plan for watersheds and rivers in advance. However, there is a lack of sediment data available for estimating sediment discharge in ungauged basins.. Thus, reasonable research is very important to evaluate and predict the sediment discharge quantitatively. In this study, cluster analysis was conducted to classify gauged watersheds into hydrologically homogeneous groups based on the watershed characteristics. Also, this study suggests a method to efficiently predict the sediment discharge for ungauged basins by developing and evaluating the SDR equations based on the PA-SDR module. As the result, the SDR equations for the classified watersheds were derived to predict the most reasonable sediment discharge of ungauged basins with 0.24 % ~ 10.89 % errors. It was found that the optimal parameters for the gauged basins reflect well characteristic of sediment movement. SDR equations proposed in this study will be available for estimating sediment discharge on ungauged basins. Also it is possible to utilize establishing the appropriate sediment management plan for integrated management of watershed and river in Korea.

• Journal of Navigation and Port Research
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• v.43 no.1
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• pp.64-71
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• 2019

It is very important to understand the mechanism of estuary topographic changes for the study of estuary management and treatment methods. In this study, the effects from the land-side, such as rainfall, river discharge, sediment discharge, and sea side, such as tide, tidal current, wave and surface sediments related to the topographic changes of the Nakdong river estuary were investigated and analyzed. Based on the analyzed data, topographic modeling was performed to analyze the topographic change and contribution of external force conditions. As a result of numerical modeling, the topographic change showed that erosion that predominates in the water directly affected by the discharge of the estuary barrage. The deposition predominates in the indirectly affected tideland. As sediments moved along the water way being sorted and distributed by the wave, the deposition predominated in the front of the barrier island. Compared with the deposition dominance, which is the result of the topographic change prediction, the impact of each external force condition gives larger erosion. However, the combined impact of each external force condition showed deposition dominant. Therefore, the topographic changes of the Nakdong river estuary are considered to be the result of various complex external factors. The impacts of each external force condition show the different contribution to each comparison area. These results should be considered when establishing the estuary management method. It must be understood that this is the result of complex interactions.

• Journal of Korean Society for Geospatial Information Science
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• v.18 no.1
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• pp.11-20
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• 2010

The distributed rainfall-runoff model which is developed in the country requires a lot of time and effort to generate input data. Also, it takes a lot of time to calculate discharge by numerical analysis based on kinematic wave theory in runoff process. Therefore, most river basins using the distributed model are of limited scale, such as small river basins. However, recently, the necessity of integrated watershed management has been increasing due to change of watershed management concept and discharge calculation of whole river basin, including upstream and downstream of dam. Thus, in this study, the feasibility of the GIS based physical distributed rainfall-runoff model, K-DRUM(K-water hydrologic & hydraulic Distributed RUnoff Model) which has been developed by own technology was reviewed in the flood discharge process for the Geum River basin, including Yongdam and Daecheong Dam Watersheds. GIS hydrological parameters were extracted from basic GIS data such as DEM, land cover and soil map, and used as input data of the model. Problems in running time and inaccuracy setting using the existing trial and error method were solved by applying an auto calibration method in setting initial soil moisture conditions. The accuracy of discharge analysis for application of the method was evaluated using VER, QER and Total Error in case of the typhoon 'Ewiniar' event. and the calculation results shows a good agreement with observed data.