• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.515-520
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• 2005

The objective of the study is to assess the water quality improvement resulted from the rearrangement of the irrigation water supply systems at Mankyeong River and Ansung Chun basin. There is a mixed type of watershed composed of urban and rural areas in the region. From the water quality analysis, showed high T-N, T-P concentration in Ansung chun and Mankyeong river caused by paddies separated widely around Ansung chun and Mankyeong river and by runoff of the pollution from the Ansung and Jeonju city. but the upstream of the river showed clean water quality, so if we use the upstream water as river maintenance water for water quality improvement, it is expected to be positive effect for rural environmental aspect.

• Korean Journal of Environmental Agriculture
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• v.21 no.4
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• pp.237-242
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• 2002

A survey on four tributaries along with Mankyeong River was carried out to get the information far the water quality improvement and control. Typical paddy farming were major agricultural practices in Kosancheon and Soyangcheon. Iksancheon was livestock raising watershed. Chucheon was urban watershed. Water quality in six sites of main stream and four sites of tributaries in Mankyeong River were investigated from May to August in 2001. The concentration of nutrient in main stream of Mankyeong River were in the range of 3.78$\sim$12.68 mg/L for total nitrogen, 0.043$\sim$0.864 mg/L for total phosphorus, 2.59$\sim$13.29 mg/L for BOD and 12.9$\sim$119.5 mg/L for COD, respectively. Water quality of Mankyeong River mostly exceeded the standard water quality criteria of Korea. Major causes of water pollution were evaluated as sewage of swine and urban area. Among the four tributaries, water quality in agricultural practices, Kosancheon and Soyangcheon was relatively less polluted. While, the highest level of water pollution measured in Iksancheon was due to livestock. The water quality of Iksancheon and Chucheon was generally more polluted in the dry period than in rainy period.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.6
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• pp.761-770
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• 2013

This study was carried out to forecast the flow rate and water quality at the inlet of the Saemangeum bay in Korea using the SWMM(Storm Water Management Model) and the WASP(Water Analysis Simulation Program), and to analyze the impacts of pollutant loading from non-point source on the water quality of the bay. The calibration and validation of flow rate and water quality were performed using those from two monitoring points in the Mankyeong river administrated by Korean Ministry of Environment as part of the national water quality monitoring network. When the river flow rate was calibrated and validated using the rainfall intensities during 2011-2012, $R^2$ (i.e., coefficient of determination) was ranged from 0.91 to 0.96. For water qualities, it was shown that $R^2$ of BOD(Biochemical Oxygen Demand) was ranged from 0.56 to 0.86, and $R^2$ of T-N(Total Nitrogen) was from 0.64 to 0.75, and $R^2$ of T-P(Total Phosphorus) was from 0.67 to 0.89. The integrated modeling system showed significant advances in the accuracy to estimate the water quality. Finally, further simulations showed that annual average flow of the river running into the bay was estimated to be $1.439{\times}10^9m^3/year$. The discharged load of BOD, T-N, and T-P into the bay were anticipated to be 618.7 ton/year, 331.5 ton/year, and 40.4 ton/year, respectively.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.540-545
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• 2006

The objective of the study is to assess the water quality improvement resulted from the rearrangement of the irrigation water supply systems at Mankyeong River and Ansung Chun basin. There is a mixed type of watershed composed of urban and rural areas in the region. The water intake facilities for agricultural use such as reservoir, weir and pumping station are generally located at upstream river where the water quality maintains relatively clean. However, this study focuses on moving the water intake to downstream and rearranging the irrigation water supply system, then investigating how effective they are for water quality improvement in the river. When the water intake is moved downstream, the stream flow is increased as much as the amount of irrigation water that is to be taken upstream. The augmented flow which is frequently referred to as environmental flow can function as dilution water for improving the quality of polluted water that is originated from the wastewater in tributaries.

• Korean Journal of Environmental Agriculture
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• v.24 no.2
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• pp.83-90
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• 2005

This study was conducted to evaluate the influence of pollutant loads on the water quality in the Mankyeong River from January 2002 to December 2004. The BOD level in upstream ranged from 0.58 to 1.57 mg $L^{-1}$, which would be in I grade according to water quality criteria by Ministry of Environment but BOD level in midstream and downstream was III grade. T-N contents were high in midstream and the average T-P level ranged from 0.06 to 2.70 mg $L^{-1}$. The point raw loads of BOD was high in Iksancheon, Mokcheonpo and Cheongha basin. The point raw loads of T-N and T-P were high in Iksancheon and Cheongha watershed. The non-point low loads of BOD were 3,931 kg $day^{-1}$, 2,870 kg $day^{-1}$ and 2,827 kg $day^{-1}$ in Mokcheonpo, Top and Jeonju watershed, respectively. The major source of BOD effluent load was population, that of T-N and T-P effluent loads was livestock. The delivered load of T-N were high in Jeonju, Mokcheonpo, Gosan, Iksancheon watershed in order. The delivered load of T-N was high in Jeonju watershed and that of T-P was high in Jeonju and Iksancheon watershed. The delivery ratio of BOD and T-N at dry season were below 100% except Mokcheonpo watershed. The delivery ratio of BOD and T-N at raining season were high in Gosan watershed.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.4
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• pp.237-244
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• 2006

The SMG project has been driven to secure food and water resources by closing of the SMG dyke for the preparation of the unification of Korean peninsular. It was investigated for pollution loads, land use distribution and water consumption for environmental assessments in two watersheds, the Mankyeong River (MK) and the Dongjin River (DJ) to assess the role of agricultural land on the alleviation of pollution loads to the SMG basin. It is needed to give the priority in managing pollution sources to conserve freshwater in the Saemangeum (SMG) basin after the completion of the SMG reclamation from tideland. The MK has $700million\;m^3$ water of which 14.1% were used for living, 73.6% for agriculture and 12.3% for industry. The DJ has $505million\;m^3$ water of which 3.0% for living, 94.5% for agriculture and 2.5% for industry. As compared to proportion of each land of total area, agricultural land was 1.4 times larger, livestock farming 7 times larger, forest 0.74 times smaller, and built-up area 0.67 times smaller in DJ watershed than in MK watershed. Pollution sources in MK and DJ watersheds were originated at a higher proportion from population including the sewage disposal and a livestock farming area rather than from the land. Water consumption and land use distribution influenced the water quality of the rivers; DJ watershed had far lower value of electric conductivity, $BOD_5$, TN and TP than MK watershed. A large proportion of paddy field also influenced to reduce pollute loadings after rainfall; DJ watershed, which has a relatively large area of paddy fields, had a far lower delivery load after rainfall than MK watershed even though DJ watershed had large livestock farming area. As paddy fields was irrigated by Iksancheon water, 37% of nitrogen, 50% of phosphates and 14.0% of $BOD_5$ was removed by the paddy field just after flowing 150 meter, and rice plants could remove TN 100.0 kg, $P_2O_5$ 24.0 kg, and $K_2O$ 119.2 kg per hectare at harvest by irrigation of Iksancheon water. Conclusively, rice paddy fields played a positive role to conserve the water quality in the Iksancheon watershed.

• Economic and Environmental Geology
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• v.41 no.6
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• pp.673-683
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• 2008

As-rich alluvial groundwaters occurring in the agricultural area of Mankyeong River watershed were geochemically studied. 15 out of 29 investigated wells (52%) showed As levels exceeding the WHO drinking water standard ($10{\mu}g/L$). Their chemistry is characterized by low Eh levels, low $NO_3$ and $SO_4$ concentrations, and high pH, alkalinity, Fe, $NH_4$, and $PO_4$ levels. This suggests that arsenic is enriched by the reductive dissolution of As-bearing Fe-/Mn-(hydro)oxides, the commonest process in Bangladesh and West Bengal of India, of which groundwaters are severely contaminated by As. It was also revealed that As concentrations in the area are strongly regulated by the presence of agrochemicals such as $NO_3$ and $SO_4$.