• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.1
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• pp.23-32
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• 2003

The objective of this study is assessing water management efficiency using water withdrawals from rivers and water requirements for paddies. The water management efficiency was defined by the ratio of water requirements and water withdrawals. Water withdrawals were estimated using the operating times and pumping capacity of the pumping stations from 1992 to 1999 in the Han River and Nakdong River basins. Water requirements were estimated by adding the evapotranspiration of the crops and infiltrations in the irrigated area. Evapotranspiration from the paddies was calculated by the FAO modified Penman method with observed daily weather data. The monthly water management efficiency was analyzed for each pumping stations and the district offices of KARICO (Korea Agricultural and Rural Infrastructure Corporation). The efficiencies of 59 pumping stations in the Han River basin varied from 19% to 135%, and the average was 61%. The efficiencies of 146 pumping stations in the Nakdong River basin ranged from 17% to 190%, and the average was 72%. There were no good correlations between the water management efficiency and pump capacity or irrigated area, it showed that the water management efficiency was affected by the traditional water management practices rather than the scale of irrigation district.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1018-1020
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• 2000

In the operation and maintenance activity of hydro turbine generator, one of the important parameters is the efficiency. This study analyze the case of efficiency management by pressure time method and survey the application of this method through the actual test. And it is confirmed that the Pressure time method exccesively limit the general condition to be applied. If index method is used for efficiency management because the index method calibrated by absolute discharge(by flow of pressure time method) is very accurate. it make to be able to manage the realtime efficiency.

• Journal of Wetlands Research
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• v.16 no.3
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• pp.363-370
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• 2014

Sewage distribution rate in rural area is only 50% level than urban area. Normally, rural area sewage is focused on the reason of water source pollution owing to rural areas were located in near water source. The Korea government is effort to manage the rural community sewage for protect the water source. In this study conducted analysis on rural community sewage treatment plant(RCSTP) nutrient treatment efficiency using operation results on winter season. Research areas are newly constructed in Bong-hwa, Yeong-yang and An-dong areas which are located in near An-dong Im-ha Dam. Based on operation result, sludge retention time(SRT) and mixed liquer suspended solid(MLSS) were effected on RCSTP nutrient treatment efficiency. Thus, it is necessary to manage of operation condition for nutrient treatment efficiency in RCSTP during the winter season.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.4
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• pp.45-53
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• 2013

Efficient water operation and management of an irrigation system plays an important element in the sustainability of irrigated agriculture. An agricultural water is delivered in many open canals of irrigation delivery system by reservoirs. The poor water distribution and management in an irrigation system is a major factor leading to low water efficiency. It is necessary to compare the estimated irrigation demands with the actual water supplies for decision making to maintain the water supply according to demand strategy. Smarter water management, new technologies and improvement of water management system, is essential to solve the problem of water efficiency and availability. In this paper, the irrigation efficiencies according to water delivery performance indicator were measured with automatic water gauge at irrigation canals, and calculated from spatial and temporal distribution of water supply for the lack of planning in water delivery. The analysis of results are obtain an insight into possible improvement methods to develop canal water management policies that enable irrigation planners to optimally manage scarce available water resources.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.5
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• pp.491-500
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• 2016

Pressure monitoring is expected to be expanded in a water distribution system according to accelerated development of smart water network management technologies caused by appearances of affordable digital infrastructures like computing, storage and bandwidth. However, the placement of pressure sensors has been determined by engineer's technical decisions since there is no well-defined criteria for deciding a suitable location of pressure sensor. This study presents a placement method of pressure sensors based on the consideration of allowable error in calibrating water network analysis modeling. The proposed method is to find a minimum set of pressure sensors for achieving a reliable management of water transmissions main and increasing the efficiency of their real-time operation. In the case study in Y area's transmission main, the proposed method shows equally distributed pressure sensors in terms of hydraulics. It is expected that the proposed method can be used to manage transmission mains stably and construct a robust real-time network analysis system as a minimal criteria.

• Journal of Korean Society of Water and Wastewater
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• v.33 no.1
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• pp.1-8
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• 2019

In this paper, the current water management organization of the Korean government and those of foreign countries were analyzed to draw out a plan to build a more rational water management organization. And then, the two organization reform alternatives were discussed on which alternatives can effectively manage the water. Through the analysis, deployment of three divisions including the water policy, the wastewater policy and the division of water industries and business are the best alternative in terms of water equality, sustainability and efficiency, which are the three main goals of the new Water Management Act, Water Management Basic Act. With much efforts, the Korea has come to the era of One Water Management. The water management paradigm proposed in this opinion is expected to become a new engine of economical growth of the nation.

• Journal of the Korean Society of Safety
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• v.34 no.4
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• pp.103-110
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• 2019

Underwater works are indispensable in the coastal and ocean engineering fields, and the reliance on manpower is higher than land works. Divers who work for a long time in a high-pressure underwater environment are always exposed to the risks of diving-related diseases. To prevent them, proper planning, operation, and management of diving by a supervisor with professional diving knowledge are required. This study provides the basic data for supervisors to plan, operate, and manage air diving for safe and efficient work in underwater construction sites. It is well-known that air diving simulations using the varying permeability model (VPM) require a longer decompression time as the water depth and the residence time in water increase. Therefore, it is crucial to have a proper surface interval through repetitive diving rather than single diving to improve the safety of the divers and the efficiency of underwater work. Furthermore, coastal and ocean engineers who manage and supervise underwater construction work must acquire expert knowledge on diving before they can plan, operate, and manage diving.

• Journal of Korean Society on Water Environment
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• v.36 no.5
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• pp.405-422
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• 2020

Land use change by urbanization has significantly affected the hydrological process including the runoff characteristics. Due to this situation, it has been becoming more complicated to manage non-point source pollutions caused by rainfall. In order to effectively control non-point sources, it is necessary to identify the reduction efficiency of the various management method based on land use characteristics. Thus, the purpose of this study is to analyze the reduction efficiency of non-point source pollution management practices targeting three different watersheds with the different land use characteristics using the Soil and Water Assessment Tool (SWAT). To do this, the vulnerable subwatersheds to non-point source pollution occurrence within each watershed were selected based on the streamflow and water quality simulation results. Then, considering the land use, low impact development (LID) or best management practices (BMPs) were applied to the selected subwatersheds and the efficiency of each management was analyzed. As a result of analysis of the non-point source pollution reduction efficiency, when LID was applied to urban areas, the average reduction efficiencies of SS, NO₃-N, and TP were 5.92%, 4.62%, and 10.35%, respectively. When BMPs were applied to rural areas, the average reduction efficiencies of SS, TN and TP were 35.45%, 4.37%, and 10.16%, respectively. The results of this study can be used as a reference for determining appropriate management methods for non-point source pollution in urban, rural, and complex watersheds.

• Journal of Korean Society on Water Environment
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• v.30 no.5
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• pp.532-538
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• 2014

A cylinder-shaped filter was developed to manage the runoff from construction sites. Compressed air was used for back-washing and pore sizes of filter were $23{\mu}m$ and $46{\mu}m$. The turbid water was prepared using sediments in construction sites. The grain size analysis showed that grains smaller than $38{\mu}m$ and larger than $335{\mu}m$ in size constituted 34.4 % and 37.6 %, respectively. Removal efficiency of the filter on turbidity, SS, COD, TN and TP showed 25~37%, 20~40%, 50~55%, 23~27% and 14~20%, respectively, whereas their removal efficiecy by using coagulant PAC showed 77~84%, 70~83%, 53~60%, 27~36%, and 59~75%, respectively. The filtration time was determined to be around 10 to 20 minutes. Back-washing for 10 seconds by pressurized air resulted in a satisfactory regeneration efficiency. According to the aforementioned test results, the cylinder-shaped filter is effective in reducing turbidity and would be suitable for practical application in construction sites and farms.

• Journal of Korean Society on Water Environment
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• v.36 no.1
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• pp.29-35
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• 2020

To manage the non-point source pollution and restore the water circulation, many technologies including infiltration or reservoir systems were installed in the urban area. These facilities have many problems regarding maintenance as their operation period becomes lengthier. The purpose of this study was to estimate the optimal maintenance timing through a long-term load test on the infiltration trench as one of the low impact development techniques. An infiltration trench was installed in the demonstration test facility, and stormwater was manufactured by Manual on installation and operation of non-point pollution management facilities from the Ministry of Environment, Korea and entered into the infiltration trench. Particle size distribution (PSD), suspended solids (SS) removal efficiency, and infiltration rate change tests were performed on inflow and outflow water. In case of the PSD, the maximum particulate size in the outflow decreased from 64 ㎛ to 33 ㎛ as the operating duration elapsed. The SS removal efficiency improved from 97 % to 99 %. The infiltration rate changed from 0.113 L/sec to 0.015 L/sec during the operation duration. The maintenance timing was determined based on the stormwater runoff requirements with these changes in water quality and infiltration rate. The methodologies in this study could be used to estimate the timing of maintenance of other low impact development techniques.