• Journal of Korean Society on Water Environment
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• v.21 no.3
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• pp.236-241
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• 2005

The purpose of this study is to find out the source(s) and distribution of boron in Nak-dong River. In the year of 2002, the boron has been adopted as a toxic constituent for Korean drinking water standard. In this study, the analytical samples were collected at 11 stations in March, June, September and December 2002. These samples were analyzed by inductively coupled plasma-mass (ICP-MS) method. The recovery, relative standard deviation and method detection limit of the ICP-MS method for boron was $89{\sim}111.3%$, $2.21{\sim}3.81%$ and $5{\mu}g/L$, respectively. The distribution of boron was ranged $65{\sim}155{\mu}g/L$ in March, $26{\sim}125{\mu}g/L$ in June, $22{\sim}140{\mu}g/L$ in September and $50{\sim}162{\mu}g/L$ in December. The higher levels of boron were found at Kum-ho river nearby the industrial complex, which seemed to be greatly affected by domestic sewages and wastewater from the upper streams. Thus, the concentration of boron and that of other components showed strong statistical correlation in this area. In the Nak-dong River, industrial wastewater and domestic sewages is thought to be the sources of boron.

• The Journal of Society for e-Business Studies
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• v.20 no.4
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• pp.1-17
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• 2015

A river water level monitoring system which prevents salt water damages and effectively excludes floods has been developed to contribute efficient operation of Nakdong river estuary barrage. The system can be used for monitoring upstream conditions more quickly and do appropriate responses over changes. Telemetry and telecontrols using PLCs have been built at the three sites that directly influence on the operation of barrage gates, and are linked to Nakdong river estuary barrage's IOS (Integrated Operation System) through public communication networks. By using PLC, the system can achieve even higher reliability and versatility than before as well as easy management. By power control devices, we can remotely control the power of PLCs to treat the minor troubles instantly without going on-sites. The power control devices also save data in preparation for the cases of communication failures. The system uses ADSL (FTTH) as a main network between SCADA server and PLCs, and CDMA (M2M) as a secondary network. In order to compensate security vulnerabilities of public communication network, we have installed the VPNs for secure communication between center and the observation stations, just like a dedicated network. Generally, river water level observations have been used custom-manufactured remote terminals to suit their special goals. However, in this case, we have established a system with open architecture considering the interface between different systems, the ease of use and maintenance, security, price, etc.

• Journal of Wetlands Research
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• v.19 no.3
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• pp.311-317
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• 2017

In this study, the water quality index was calculated using the water quality monitoring data in the Nakdong River water system and the water quality status was compared with the living standard. The water quality index was selected by the RWQI method CCME-WQI currently used by the Ministry of Environment. The water quality items were selected as 7 items for pH, DO, EC, water temperature, TOC, T-N and T-P. The evaluation period was selected from the last three years (2013~2015) and water quality monitoring data measured within the period were used. As a result of the evaluation, the results of the previous evaluation showed similar tendency to the index of living environment, but the monthly evaluation showed different BOD and T-P results. Therefore, it is concluded that it is more reliable that more complex evaluation than single water quality evaluation is needed for efficient river management.

• Journal of Korean Society on Water Environment
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• v.23 no.1
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• pp.64-71
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• 2007

In this study daily flow data is constructed from 8-day intervals flow data which has been measured by Nakdong River Water Environmental Laboratory. TANK model is used to expand 8-day intervals flow data into daily flow data. Using the Sequential quadratic programing, TANK model is auto-calibrated with daily precipitation and 8-day interval flow data. Generated and measured daily surface flow, ground water flow data and ground water recharge are shown to be in a good agreement. From this result, it is thought that this method has the potential to provide daily flow data for calibrating an watershed model such as SWAT.

• The Journal of Engineering Geology
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• v.16 no.2 s.48
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• pp.145-152
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• 2006

Industry development caused numerical and quantitative increase of noxious chemical substances that contain risk assessment in water resources. For use of efficient water resources a pre-treatment of contaminant source which is flowed in water resources is recognized in essential process. Therefore, the discharged water quality from discharged company began to control contaminant by total amount of pollutant in domestic. However, to estimate closely chemical substances it is not proved up to now, monitoring is very important. This study achieved a monitoring of micro noxious chemical substance by fiber and chemistry industrial wastewater inflow to examine risk assessment of the water system of Nakdong river. Chloroform was measured highest among volatile organic compounds (VOCs) that the results of water quality of influent and effluent are detected from 7 companies of study area. The other side, because measured value of detected chloroform is indefinite detection level in the same company, it is difficulty in management of water quality. However it may not be much effects of the water system of Nakdong river because these company's effluent is high treatment efficiency of chloroform (more than 88%) in sewage treatment plant. On the other hand, in the investigated results for the European Union specified priority substance that is detected to relationship influent and effluent from fiber/chemistry associated industries, these substances were not detected and domestic data was hardly referred. Therefore, data construction of continuous monitoring about this water quality may have to be achieved certainly to utilize as country policy.

• Economic and Environmental Geology
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• v.56 no.4
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• pp.435-445
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• 2023

A delta is a depositional landform that is formed when sediment transported by a river is deposited in a relatively low-energy environment, such as a lake, sea, or a main channel. Among these, a delta formed at the confluence of rivers has a great importance in river management and research because it has a significant impact on the hydraulic and sedimentological characteristics of the river. Recently, the equilibrium state of the confluence area has been disrupted by large-scale dredging and construction of levees in the Nakdong River. However, due to the natural recovery of the river, the confluence area is returning to its pre-dredging natural state through ongoing sedimentation. The time-series data show that the confluence delta has been steadily growing since the dredging, but once it reaches a certain size, it repeats growth and retreat, and the overall size does not change significantly. In this study, we developed a model to explain the sedimentation-erosion processes in the confluence area based on the assumption that the confluence delta reaches a dynamic equilibrium. The model is based on two fundamental principles: sedimentation due to supply from the tributary and erosion due to the main channel. The erosion coefficient that represents the Nakdong River confluence areas, was obtained using data from the tributaries of the Nakdong River. Sensitivity analyses were conducted using the developed model to understand how the confluence delta responds to changes in the sediment and water discharges of the tributary and the main channel, respectively. We then used annual average discharge of the Nakdong River's tributaries to predict the dynamic equilibrium positions of the confluence deltas. Finally, we conducted a simulation experiment on the development of the Gamcheon-Nakdong River delta using recorded daily discharge. The results showed that even though it is a simple model, it accurately predicted the dynamic equilibrium positions of the confluence deltas in the Nakdong River, including the areas where the delta had not formed, and those where the delta had already formed and predicted the trend of the response of the Gamcheon-Nakdong River delta. However, the actual retreat in the Gamcheon-Nakdong River delta was not captured fully due to errors and limitations in the simplification process. The insights through this study provide basic information on the sediment supply of the Nakdong River through the confluence areas, which can be implemented as a basic model for river maintenance and management.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.354-358
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• 2011

Small hydropower is one of the many types of new and renewable energy, which South Korea is planning to develop, as the country is abundant in endowed resources. In order to fully utilize small hydropower resources, there is a need for greater precision in quantifying small hydropower resources and establish an environment in which energy sources can be discovered using the small hydropower resource management system. This study has given greater precision to calculating annual electricity generation and installed capacity of small hydropower plants of Nakdong river system by inquiring into average annual rainfall, basin area and runoff coefficient, which is anticipated to promote small hydropower resources utilization. Small hydropower resource management system was also established by additionally providing base information on quantified small hydropower resources and analysis function and small hydropower generator status, rivers, basin, rainfall gauging station, water level gauging station etc.. Small hydropower resource management system can be used gather basic information for positive applications of small hydropower energy nationwide.

• Journal of the Korean earth science society
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• v.42 no.4
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• pp.412-424
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• 2021

Understanding the distribution of heavy metals in sediment is necessary because labile heavy metals can partition into the water column and bioaccumulate in aquatic organisms. Here we investigated six heavy metals (Co, Cu, Mn, Ni, Pb, and Zn) in sediment cores using a five-step sequential leaching method to examine the occurrence of heavy metals in the sediment. The results showed that all elements, except Mn, are depleted in the exchangeable and carbonate fractions. However, heavy metal concentrations are much higher in the Fe-Mn oxide and organic matter fractions, especially for Cu, indicating enrichment in the organic matter fraction. Furthermore, contamination parameters (contamination factor and geoaccumulation index) indicate that Mn contamination is high, primarily derived from anthropogenic sources, presenting a potential risk to ecosystems in the Nakdong River.

• Journal of the Korean Solar Energy Society
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• v.32 no.6
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• pp.68-75
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• 2012

Small hydropower is one of the many types of new and renewable energy, which is planning to develop, as the country is abundant in endowed resources. In order to fully utilize small hydropower resources, there is a need for greater precision in quantifying small hydropower resources and establish an environment in which energy sources can be discovered using the small hydropower resource management system. This study has given greater precision to calculate annual electricity generation and capacity of small hydropower plants of Nakdong river system by inquiring into average annual rainfall, basin area and runoff coefficient, which is anticipated to promote small hydropower resources utilization. Small hydropower resource management system was also established by additionally providing base information on quantified small hydropower resources and analysis function and small hydropower generator status, rivers, basin, rainfall gauging station, water level gauging station etc.. Small hydropower resource management system can be used gather basic information for positive applications of small hydropower energy nationwide.

• Journal of Environmental Science International
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• v.24 no.11
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• pp.1343-1362
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• 2015

As a result of analysis based on the observed data for BOD, COD and TOC in order to manage non-biodegradable organics in the Geumho River, COD/BOD ratio was analyzed as the occupying predominance proportion. In this study, the classification(changes in water quality measurement : increase, equal, decrease) and measurement of BOD and COD were analyzed for trends over the past 10 years from 2005 to 2014 in the Geumho River. The Geumho River is expected to need non-biodegradable organics management because BOD was found to be reduced 61.1% and COD was found to be increased 50%. As a result of the analysis of land use, the Geumho-A is a unit watershed area of $921.13km^2$, which is the most common area that is occupied by forests. The Geumho-B is a unit watershed area of $436.8km^2$, which is the area that is highest occupied by agriculture and grass of 24.84%. The Geumho-C is a unit watershed area of $704.56km^2$ accounted for 40.29% of the entire watershed, which is the area that is occupied by urban of 15.12%. Load of non-biodegradable organics, which is not easy biodegradable according to the discharge, appeared to be increased because flow coefficient of COD and TOC at the Geumho-B were estimated larger than 1 value. The management of non-point sources of agricultural land is required because the Geumho-B watershed area occupied by the high proportion of agriculture and field. In this segment it showed to increase the organics that biodegradation is difficult because the ratio of BOD and TOC was decreased rapidly from GR7 to GR8. Thus, countermeasures will be required for this.