• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.500-504
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• 2008

The objective of this paper is to evaluate the feasibility of using an optimization model as a effective way to search conjunctive operation scheme to meet two conditions; one is to minimize the electric cost for pumping and another is to meet the water demand for satisfying customers. The feasibility is confirmed as comparing the best combinations of pumps between multi-regional water supply networks from multiple sources which are obtained through an optimization modeling and EPAnet modeling. KModsim model, a network optimization model, was used to determine conjunctive operation scheme in the pipe system. KModsim, based on Lagrangian Relaxation algorithm, is useful for modeling network system and obtaining simultaneously pump combination and water allocation with given input option such as energy unit cost supplying from a source into a consumer, operating pumping combination. This study develops the procedure of determining optimal conjunctive operation scheme with using KModsim model. As a study region, the water supplying systems of the Geojae-city in the Geongsang Namdo Province was selected and investigated. The EPAnet hydraulic simulation result(Ryu et al, 2007, KSWW) gave input data for optimization model; energy unit price(won/$m^3$), water service available area etc.. It was assured that the combination of pump operation through optimum conjunctive operation is to be optimum scheme to obtain the best economic water allocation with comparison to the hydraulic simulation result such as electric cost and pump combination cases. The results obtained through the study are as follows. First, It was found that a well-allocated water supply scheme, the best combination of pump operation through optimum joint operation, promises to save the electric cost and satisfy all operational goals such as stability and revenues during the period. Second, an application of KModSim, a network model, gave the amount of water allocation from each source to a consumer with consideration of economic supply. Finally, in a service area available to supply through conjunctive operation of existing inter-regional water supply networks within short distance, a conjunctive operation is useful for determining each transmission pipeline's service area and maximizing the effectiveness of optimizations in pumping operation time.

• Journal of Korea Water Resources Association
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• v.32 no.5
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• pp.537-545
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• 1999

This study examines three counterplans for the improvement in price structure of Korean multi-regional water supply system. First, price differentiation between industrial and residential water uses is analyzed using several pricing methods. It has been estimated that the industrial water price by the Ramsey pricing method is needed to be two to two and half times higher than the price of residential water to achieve maximum social welfare. Second, peak-load pricing is then studied to seek for the effectiveness of seasonal differentiation in water price. It has been found that consideration of dam facilities and their functions is the key factor for the effectiveness of the seasonal differentiation in water price. Finally, the discussion about the introduction of contract pricing system to the multi regional water supply system to achieve optimal investment plan for the future water demand is presented. We has found that the introduction of contract pricing system will greatly increase the efficiency in future investment plan of the multi-regional water supply system.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.516-516
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• 2022

Agricultural reservoirs are critical water resources structures to ensure continuous water supplies for rice cultivation in Korea. Climate change has increased the risk of reservoir failure by exacerbating discrepancies in upstream runoff generation, downstream irrigation water demands, and evaporation losses. In this study, the variations in water balance components of 400 major reservoirs during 1973-2017 were examined to identify the reservoirs with reliable storage capacities and resilience. A conceptual lumped hydrological model was used to transform the incident rainfall into the inflows entering the reservoirs and the paddy water balance model was used to estimate the irrigation water demand. Historical climate data analysis showed a sharp warming gradient during the last 45 years that was particularly evident in the central and southern regions of the country, which were also the main agricultural areas with high reservoir density. We noted a country-wide progressive increase in average annual cumulative rainfall, but the forcing mechanism of the rainfall increment and its spatial-temporal trends were not fully understood. Climate warming resulted in a significant increase in irrigation water demand, while heavy rains increased runoff generation in the reservoir watersheds. Most reservoirs had reliable storage capacities to meet the demands of a 10-year return frequency drought but the resilience of reservoirs gradually declined over time. This suggests that the recovery time of reservoirs from the failure state had increased which also signifies that the duration of the dry season has been prolonged while the wet season has become shorter and/or more intense. The watershed-irrigated area ratio (W-I_ratio) was critical and the results showed that a slight disruption in reservoir water balance under the influence of future climate change would seriously compromise the performance of reservoirs with W-I_ratio< 5.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.3
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• pp.71-83
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• 2020

Resilience is the capacity to maintain essential services under a range of circumstances from normal to extreme. It is achieved through the ability of assets, networks, systems and management to anticipate, absorb and recover from disturbance. It requires adaptive capacity in respect of current and future risks and uncertainties as well as experience to date. The agricultural infrastructures with high resilience can not only reduce the size of the disaster relatively, but also minimize the loss by reducing the time required for recovery. This study aims to evaluate the most suitable drought countermeasures with the analysis of various resilience indices by predicting future agricultural water shortage under land use and climate change scenarios for agricultural areas in Jeju Island. The results showed that the permanent countermeasure is suitable than the temporary countermeasures as drought size and the cost required for recovery increase. Wide-area water supply system, which is a kind of water grid system, is identified as the most advantageous among countermeasures. It is recommended to evaluate the capability of agricultural infrastructure against drought with the various Resilience Indices for reliable assessment of long-term effect.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.27 no.5
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• pp.444-455
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• 1998

1960년 이후 급속한 경제성장과 산업화에 따라 도시의 인구 집중과 핵가족화 현상으로 주택에 대한 수요가 증가하자 공동주택을 짧은 기간에 대량으로 공급하지 않을 수 없게 되었다. 이 결과 1995년 국내 통계에 의하면 도시주택 유형 중 아파트가 48.1%를 차지할 만큼 대표적인 공동주거 형태로 자리잡게 되었으며 가용택지의 부족은 이후로도 단독주택보다 아파트와 같은 공동주택 건설의 중대를 야기할 것으로 예상된다.

• Journal of Korea Water Resources Association
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• v.43 no.1
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• pp.95-104
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• 2010

The tap water supply in Korea mainly depends on the surface water. However, the advanced water purification process becomes a necessity due to the deterioration of surface water quality and the risk of accidental spill. High cost of water treatment and public concerns make the decision makers turn to riverbank filtration as an alternative to the surface water. Riverbank filtration has been employed for water supply in many developed countries for more than 150 years. In Korea, riverbank filtration has drawn attention since 1990s as a supply source having potential to stably meet the ever-increasing water demand. Some cities located in the Nakdong River Basin are currently supplying water through riverbank filtration. This work studies the site suitability analysis for riverbank filtration using game theory. Theory of games, which is a branch of applied mathematics used in social sciences (most notably economics), biology, engineering and computer science, was applied to candidate locations for the selection of riverbank filtration site. We proposed a policy game model as a new method adopting a probabilistic approach. The model developed turned out to be an effective tool for site selection.

• Journal of Korean Society of Disaster and Security
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• v.14 no.4
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• pp.61-67
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• 2021

In this study, the adequacy of water supply critical factors of urban design was examined. The supply of water supply is analyzed in various ways as the design progresses. Starting with basic data collection and analysis a supply and demand plan is established to calculate the amount of water supply and in this study the adequacy of population estimation and original unit calculation was evaluated. Among the second new cities where actual data can be secured Wirye New Town was selected as the study target area. Related data were analyzed to confirm the future population and the original unit and compared with the measured data. As of September 2020, the population of Wirye New Town was 93,977, showing the appropriateness of about 84% with a planned population of 110,990 confirming that the planned population and the actual population were almost similar. In the case of the original unit, it was calculated as 314 liters per person in Seoul and 320 liters per person in Seongnam at the time of design. As a result, it was found that there was some agreement in the population estimation while examining the supply in the planned city. In the case of Korea, there is a lot of interest in revitalizing the existing city, away from continuous development. Therefore it is judged that there is a need for further research on the adequacy of supply for the old city center.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.3
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• pp.15-25
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• 2005

Ninety tow percent of over 1,800 gate controlled dams in Korea are classified as small dams. The primary purpose of these small dams is to supply irrigation water. Therefore, while large dams can store as much as 80 percent of precipitation and thus are efficient to control flood, small dams are often lack of flood control function resulting in increased susceptibility drought and flood events. The purpose of this study is to develope a storage management model for irrigation dams occupying the largest portion of small dams. The proposed Storage Management Model (STMM) can be applied to the Seongju dam for efficient management. Besides, the operation standard is capable of analyzing additional available water, considering water demand and supply conditions of watershed realistically. And the model can improve the flood control capacity and water utilization efficiency by the flexible operation of storage space. Consequently, if the small dams are managed by the proposed Storage management model, it is possible to maximize water resources securance and minimize drought and flood damages.

• Spatial Information Research
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• v.16 no.2
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• pp.263-278
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• 2008

Nowaday, local governments have planned to manage intelligent underground facilities through the u-City project. But, the intelligent underground facilities are in need of the progressive approach because of the required huge financial resources. Therefore, the objectives of this research are (1) to prioritize the monitoring items of sensing technology developments, (2) to study technological feasibilities, and (3) to discover the killer application which expands ripple effects on economy. To achieve these objectives, final monitoring items were derived from the business analysis of the water supply, the local government survey, the hearing expert opinions and so on. The priority order of final monitoring items were technology developments of (1) the flowmeter flux, (2) the water leakage/crack, (3) the pressure of water supply pipes, and (4) the flux of filtration plants. The research significance is obtained from the derivation and the evaluation of the priority order and the actual demand for the water supply facility management. And, the research results will contribute to the strategic planning for the underground facility intelligence.

• Journal of Korea Water Resources Association
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• v.52 no.10
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• pp.719-728
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• 2019

Valve in water distribution network (WDN), that controls the flow in pipes, is used to isolate a segment (a part of WDN) under abnormal water supply conditions (e.g., pipe breakage, water quality failure event). The segment isolation degrades pressure and water serviceability in neighboring area during the water service outage of the segment. Recent hydraulic and water quality failure events reported encouraging WDN valve installation based on various abnormal water supply scenarios. This study introduces a scenario-based optimal valve installation approach to optimize the number of valves, the amount of undelivered water, and a shortest water supply path indicator (i.e., Hydraulic Geodesic Index). The proposed approach is demonstrated in the valve installation of Pescara network, and the optimal valve sets are obtained under multiple scenarios and compared to the existing valve set. Pressure-driven analysis (PDA) scheme is used for a network hydraulic simulation. The optimal valve set derived from the proposed method has 19 fewer valves than the existing valve set in the network and the amount of undelivered water was also lower for the optimal valve set. Reducing the reservoir head requires a greater number of valves to achieve the similar functionality of the WDN with the optimal valve set of the original reservoir head. This study also compared the results of demand-driven analysis (DDA) and the PDA and confirmed that the latter is required for optimal valve installation.