• Journal of Korea Water Resources Association
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• v.49 no.12
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• pp.1027-1034
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• 2016

One of the most important purpose of multi-purpose reservoir is storing a large amount of water for utilization in a dry season. However, multi-purpose reservoirs that were constructed according to the limited hydrologic information available at the time of construction may encounter problems such as decreased water inflow due to climate change and an inability to cope with a water shortage. To solve these problems, in 2015, the Ministry of Land, Infrastructure and Transport suggested a revised water supply standard in case of water shortage for reservoirs. However, the revised standard has not been sufficiently discussed to determine its effectiveness. In addition, multi-purpose reservoirs in South Korea have secured and stored water for emergencies, but there is currently no way to utilize the stored water. Determining how to utilize the stored water effectively may be a useful method for preparing drought. Therefore, this article discusses the revised water supply standard as it relates to a water shortage in reservoirs and a method of utilizing the water stored for emergencies in multi-purpose reservoirs. The options for utilizing the water storage were evaluated using a water shortage safety degree index, and the results showed that the options may slightly and limitedly increase the water supply capacity. However, the evaluation also showed that a complex application of two options may overcome the exisiting problem and to supply water more effectively.

• Journal of Korea Water Resources Association
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• v.51 no.spc
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• pp.1127-1134
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• 2018

According to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), climate change increases the frequency of abnormal weather phenomenon. As the frequency of abnormal weather phenomenon increases, frequency of disasters related to water resources such as floods and droughts also increases. Drought is the main factor that directly affects water supply. Recently, the intensity of drought and the frequency of drought occurrence have increased in Korea. So, there is a need for water resource securing technology for stable water supply. Korean Water Plan mentioned that water reserves concept is necessary for stable water supply. Most multi-purpose reservoirs in Korea have emergency storage in addition to conservation storage used for water supply. However, there is no clear use standard for emergency storage. This study investigated the use of reservoir reserves for stable water supply. In order to consider the climate change impact, the AR5-based hydrological scenario was used as inflow data for the reservoir simulation model. Reservoir simulations were carried out in accordance with the utilization conditions of emergency storage and water supply adjustment standard. The optimal reserves for each multi-purpose reservoirs was estimated using simulation results.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.155-155
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• 2016

화석연료 사용으로 인한 지구온난화는 평균 기온 및 해수면 상승과 함께 기후변화를 야기하여 수자원 관리에 어려움을 증대시키고 있다. 우리나라도 기후변화로 인한 홍수 및 가뭄의 피해가 커지고 있으며 심도 또한 증대되고 있는 추세이다. 이러한 문제를 해결하기 위해 수자원 시설물을 건설하여 대비하고 있지만 설계 당시 이용할 수 있었던 수문자료의 한계로 인해 최근 발생하고 있는 문제를 해결하기엔 어려움이 있다. 또한 대부분의 다목적댐은 가뭄과 같은 비상 상황에 활용할 수 있도록 비상용량을 확보하고 있음에도 불구하고 사용에 관한 명확한 기준이 없어 거의 활용되지 않고 있는 실정이다. 본 연구에서는 가뭄에 취약한 낙동강 유역 중 이수용량 대비 비상용량이 가장 큰 합천댐을 대상으로 HEC-ResSim 모형을 이용하여 실제 다목적댐에 적용된 용수공급조정 기준을 고려한 비상용량 활용에 따른 용수공급능력 변화를 모의하였다.

• Journal of Biosystems Engineering
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• v.42 no.4
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• pp.350-357
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• 2017

Purpose: In-situ monitoring of water quality is fundamental to most environmental applications. The high cost and long delays of conventional laboratory methods used to determine water quality, including on-site sampling and chemical analysis, have limited their use in efficiently managing water sources while preventing environmental pollution. The objective of this study was to develop an on-site water monitoring system consisting mainly of an Arduino board and a sensor array of multiple ion selective electrodes (ISEs) to measure the concentration of $NO_3$ ions. Methods: The developed system includes a combination of three ISEs, double-junction reference electrode, solution container, sampling system consisting of three pumps and solenoid valves, signal processing circuit, and an Arduino board for data acquisition and system control. Prior to each sample measurement, a two-point normalization method was applied for a sensitivity adjustment followed by an offset adjustment to minimize the potential drift that could occur during continuous measurement and standardize the response of multiple electrodes. To investigate its utility in on-site nitrate monitoring, the prototype was tested in a facility where drinking water was collected from a water supply source. Results: Differences in the electric potentials of the $NO_3$ ISEs between 10 and $100mg{\cdot}L^{-1}$ $NO_3$ concentration levels were nearly constant with negative sensitivities of 58 to 62 mV during the period of sample measurement, which is representative of a stable electrode response. The $NO_3$ concentrations determined by the ISEs were almost comparable to those obtained with standard instruments within 15% relative errors. Conclusions: The use of the developed on-site nitrate monitoring system based on automatic sampling and two-point normalization was feasible for detecting abrupt changes in nitrate concentration at various water supply sites, showing a maximum difference of $4.2mg{\cdot}L^{-1}$ from an actual concentration of $14mg{\cdot}L^{-1}$.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.1
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• pp.17-22
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• 2013

In this study, a pH control method by carbon dioxide ($CO_2$) was applied to coagulation process in water treatment plant (WTP) to investigate the coagulation efficiency and residual dissolved aluminum when high pH raw water is flowing into the plant during algal blooming. Existing coagulant dose (1 mg/L in raw water) resulted in the pH reduction of 0.0384 by LAS, 0.0254 by PAC, 0.0201 by A-PAC, and 0.0135 by PACS2, respectively. And then the concentration of dissolved aluminum was 0.02 mg/L at pH 7.44, 0.07 mg/L at pH 7.96, 0.12 mg/L at pH 8.16, 0.39 mg/L at pH 8.38 showing the concentration increase with pH in the coagulation process. It was noteworthy that rapid increase was observed at pH above 8.0 next the rapid mixing. Therefore it is necessarily required to control pH below 7.8 in the coagulation process in order to meet drinking water quality standard of aluminum for high pH raw water into WTP, $CO_2$ injection could control pH successfully at about 7.3 even for the raw water of high pH above 8.0. In addition it was found that the pH control by $CO_2$ injection was significantly effective for coagulation in terms of turbidity removal, coagulant dosage, and residual dissolved aluminum concentration.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.491-491
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• 2017

K-water에서는 가뭄으로 인한 피해를 완화시키기 위해 '댐 용수공급 조정 기준'을 만들어 전국 다목적 댐들을 대상으로 시범적으로 적용하고 있다. 그런데 가뭄 기간(2008~2009)에 대하여 합천댐의 용수공급 조정기준을 이용해 저수지를 모의운영한 결과, 이 기준은 가뭄에 효과적으로 대응하지 못할 수도 있다고 판단되었고, 그에 따라 대안 기준을 제시하고자 한다. 용수공급 조정기준은 가뭄 대응 단계를 4단계(관심, 주의, 경계, 심각)로 나누고 있으며, 순단위로 각 단계별 감량공급 실행 저수량과 감량 공급량을 제시하고 있다. 이기준을 이용한 합천댐의 모의 운영 결과, 가뭄기간동안 용수공급에 실패한 경우가 발생하였다. 이는 K-water의 합천댐 용수공급 조정 기준이 가뭄 대응에 적합하지 못할 수도 있다는 것을 의미한다. 본 연구에서 제시하고자 하는 대안은 이산화 용수 감량공급 기법에서 도출된 용수 감량공급 현 저수량 기준곡선이다. 과거 심각한 가뭄이 발생한 1994년과 1995년을 대상으로 하여 기준곡선을 도출하였으며, 각 단계별 감량공급 실행 저수량은 혼합정수계획법을 이용해 결정하였다. 또한, 이 기준곡선을 이용하여 동일한 가뭄 기간 (2008~2009)에 대해 저수지 모의운영을 실시하였다. 그 결과 K-water의 합천댐 용수공급 조정 기준을 적용한 모의운영 결과에서는 용수공급 실패가 발생한데 비해 대안으로 제시하는 기준곡선을 적용한 모의운영 결과에서는 용수공급을 실패한 경우가 없었다. 이는 대안으로 제시한 기준곡선이 K-water의 기준곡선에 비해 가뭄 대응에 보다 적합한 것을 의미한다. 그 이유로는 대안으로 제시한 기준곡선의 감량공급 실행 저수량이 댐 용수공급 조정 기준의 값들보다 커 미리 감량공급이 이루어지기 때문이다.