• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.327-328
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• 2021

In the manufacturing process of ready-mixed concrete, quantity management directly affects the workability and strength of concrete. Therefore, water quantity is the most important management factor for water quality control of ready-mixed concrete. It can be said that the number of unit water in the mix design, the water quantity due to the surface water contained in the aggregate used, and the water quantity taking into account the concentration of sludge contained in the recycling water when using the recycling water are factors that affect the quantity management of ready-mixed concrete. In this study, as a stable quality control method of ready-mixed concrete, a quantity management method by aggregate surface water and a sludge concentration management method according to the use of recycling water were proposed. Thus, we tried to suggest an efficient quantity management method for stabilizing the quality of ready-mixed concrete.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.379-383
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• 2015

Indicators of environmental conditions describe the state of the environment and the quantity and quality of natural resources. This study deduced the evaluation items to assess each sub-indicator for agricultural water quality and conducted the surveying using the Delphi method based on agricultural water quality experts. Considering its importance, environmental, state, and management indicators showed that state indicator such as COD concentration for surface water and $NO_3-N$ concentration for groundwater was ranked as first and followed by amount of fertilizer. Its indicators were correlated with state and environmental indicators in surface water and groundwater. The best management indicators were calculated to assess the agricultural surface water and ground water quality. The indicator could be used in established policies for management and conservation of water resources.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09a
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• pp.42-43
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• 2005

• KCID journal
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• v.19 no.1
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• pp.19-29
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• 2012

The data of the agricultural water quality survey network was analyzed between from 1990 to 2010 in order to propose effective plans for water quality management by analyzing the characteristics of agricultural lakes and the change of water quality. The result of the analysis shows that there is a correlation between water quality and items that can be a function of water depth such as dam height, dam length, dam height/dam length ratio and active storage/surface area of lake ratio. This means that, Korean agricultural lakes, there is a correlation between water quality and water depth. Water quality of the lakes that have lower than 5m of active storage/surface area of lake ratio (effective water depth) especially tends to get worse rapidly. The Chl-a and COD concentration of Korean agricultural lakes have a tendency to increase between June and September. Therefore, we recommend first taking a water quality improvement project for the lakes preformed watershed management project, and taking a preventive short-term water quality improvement project for the unperformed lakes before June among lakes that have lower than 5m of effective water depth.

• KCID journal
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• v.17 no.2
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• pp.95-104
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• 2010

Water quality data for 10 years (2000~2009) from about 826 reservoirs that are operated as a agricultural water quality survey network were analyzed in order to seek water quality management plan based on physical and chemical characteristics of agricultural reservoirs. The 95% reservoirs that exceed agricultural water quality standard of Chl-a (35mg/ $m^3$) had effective water depth shallower than 5m. The reason was that the reservoirs had more inflows of nutrient salts from the watershed, bigger surface water area of weak structure to algae occurrence. As the reservoirs of effective water depth shallower than 5m cover 49% of benefited area for irrigation, it is critical for agricultural water quality management of the reservoirs. The water quality of reservoir with shallower than 5m effective water depth was worse than reservoir with deeper than 5m effective water depth. Therefore, it is desirable that effective water depth of reservoirs make more than 5m for water quality management by building the bank higher and dredging the bottom of reservoirs.

• Journal of Environmental Policy
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• v.10 no.4
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• pp.61-80
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• 2011

Through concentrated investments in environmental regulations centered around BOD, which is a biodegradable matter index, and basic environmental infrastructures, national BOD pollution level has continuously improved. Nonetheless, limitations of BOD management system has become evident through nation-wide stagnation and/or increases of refractory organic matters, such as COD, at main drinking water sources, and the need for a new index, which can easily indicate different environmental conditions, has increased. Therefore, this study suggests a new organic management index for a proper management of surface water. $COD_{Cr}$ and TOC were examined as candidates for surface water quality management index, and it was found that TOC was more appropriate than $COD_{Cr}$ as an organic matter management index. Through this study, it was found that TOC possesses following qualities: a more representative index; international acceptability; monitoring program is easier; better availability of analysis techniques; better accuracy and precision of analysis; less time required for analysis; ease of operation; management of disinfection byproducts; connection with present policies; existence of foreign and domestic application case studies; and correlation with water ecosystem.

• Journal of Korean Society on Water Environment
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• v.26 no.1
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• pp.125-132
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• 2010

Characterization of sediment quality is important for the proper management of surface water quality, yet sediment has not been monitored sufficiently. In this study, fecal indicator microorganism concentrations of sediments in the Geum River Basin were monitored. Sampling was carried out at one paddy field, one lakeshore and five monitoring stations in the lower reach of the Geum River Basin. Surface waters and sediments were sampled four times during rainy season. Total coliform concentrations of sediments were 12 times higher in average to those of surface waters while E. coli concentrations of sediments were six times higher. No correlation found between indicator microorganism concentration between surface waters and sediments.

• Journal of Soil and Groundwater Environment
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• v.26 no.6
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• pp.176-185
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• 2021

This paper aims to develop a new paradigm for groundwater management which is compatible with integrated water management policies in Korea. Three key roles of groundwater are defined for addressing water cycle distortion, high water stress, water quality degradation, aquatic ecosystems deterioration, and water-related hazards. Firstly, groundwater plays an important role in contributing soundness of water cycle as a component of water cycle. Secondly, it is a local water resource to ensure water supply sustainability. Thirdly, groundwater is an essential water resource for drought and emergencies. In order to support the groundwater roles, we propose a paradigm shift for groundwater management and policy directions towards integrated water management. The new paradigm consists of managements for sound water cycle on a watershed scale and groundwater environment(quantity, quality, and groundwater dependent ecosystems) managements for both human and nature. A prospective management also constitutes the new paradigm. In addition, this paper proposes four policy directions in groundwater management. The policies emphasize the integrated management of groundwater and surface water, management of groundwater environment(quantity, quality, and groundwater dependent ecosystems), management of groundwater uses for water sustainability and security, and enhancement of groundwater publicity.

• Journal of Korean Society on Water Environment
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• v.22 no.5
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• pp.748-756
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• 2006

Accurate and timely information on status and trends in the environment is necessary to shape sound water quality management policy and to implement water quality improvement programs efficiently. One of the most effective ways to communicate information on water quality trends to policy-makers, scientists, and the general public is with comprehensive water quality indices. The derivation and structure of a water quality index (WQI) for the classification of surface water quality is discussed. The WQI generally developed through the selection, transformation and weighting of determinants with rating curves based on legal standards and quality directives or guidelines. The representative pollutants should be included in the index, and the relationship between the quantity of these pollutants in the water and the resulting quality of the water should be based on scientific results. The WQI be simply and meaningfully formulated that nonscientifically trained users can easily become familiar with the framework of the system and use the output data to evaluate their own pollution problems.

• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.597-602
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• 2004

Field experimental study was performed to examine characteristics of nutrient export from paddy rice fields with irrigation practices. Experimental fields with surface-water and ground-water irrigation were monitored and analyzed during rice culture period. The water balance showed that outflow generally balanced the inflow showing that about half (58~68%) of total outflow was lost by surface drainage. Water and nutrient export are more in surface-water irrigation paddy than in ground-water irrigation paddy. The reasons might be more irrigation water available and easy to use in surface-water irrigation. If irrigation water reduced, it could result in reduction of nutrient export in paddy rice fields, which can save water and protect water quality. However, deviation from conventional standard practices might affect the rice yield and further investigations are necessary.