• Journal of Korean Society on Water Environment
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• v.26 no.3
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• pp.439-445
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• 2010

An emergy analysis of the main energy flows driving the economy of humans and life support systems consists of environmental energies, fuels, and imports, all expressed as solar emjoules. Total emergy use (371 E20 sej/yr) of the Western Nakdong River Basin is 97 per cent from imported sources, fuels and goods and services. Emergy flows from the environment such as rain and geological uplift flux accounted for only 2.9 percent of total emergy use. Emergy yield ratio and environment loading ratio were 1.03 and 33.27, respectively. Emergy sustainability index, a ratio of emergy yield ratio to environment loading ratio, is therefore less than one, which is indicative of highly developed consumer oriented economies. It is necessary for an efficient management of Western Nakdong River Basin to reduce pollution load basically and to restructure economic activities into an environmental friendly industrial structure depending on renewable energy and resources.

• Journal of Korean Society of Water and Wastewater
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• v.36 no.3
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• pp.149-165
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• 2022

The water consumption data of individual consumers must be analyzed and forecast to establish an effective water demand management plan. A k-mean cluster model that can monitor water use characteristics based on hourly water consumption data measured using automated meter reading devices and demographic factors is developed in this study. In addition, the quantification model that can estimate the daily water consumption is developed. K-mean cluster analysis based on the four clusters shows that the average silhouette coefficient is 0.63, also the silhouette coefficients of each cluster exceed 0.60, thereby verifying the high reliability of the cluster analysis. Furthermore, the clusters are clearly classified based on water usage and water usage patterns. The correlation coefficients of four quantification models for estimating water consumption exceed 0.74, confirming that the models can accurately simulate the investigated demographic data. The statistical significance of the models is considered reasonable, hence, they are applicable to the actual field. Because the use of automated smart water meters has become increasingly popular in recent year, water consumption has been metered remotely in many areas. The proposed methodology and the results obtained in this study are expected to facilitate improvements in the usability of smart water meters in the future.

• Journal of Korean Society of Rural Planning
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• v.11 no.4 s.29
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• pp.59-65
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• 2005

Proper management of small rural watershed is important since it does affect water quality improvement of larger scale watershed. Therefore, effective small watershed management guideline including participatory program of local people is required to achieve water environment improvement. Feasibility of water quality goal, short and long-term watershed management plan and funding sources were investigated by field monitoring of Hampyungchun watershed which has characteristics of rural stream, and literature review. The relevant parties and their roles fer watershed management were identified and suggested. A hybrid model, that is mixture of government driven model and NGO model, is recommended for watershed management organization in this study.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.4
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• pp.511-517
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• 2015

Korea's modern waterworks began with construction of DDukdo water treatment plant in 1908 and has been growing rapidly along with the country's economic development. As a result, water supply rates have reached 98.5% based on 2013. Despite multilateral efforts for high-quality water supply, such as introduction of advanced water treatment process, expansion of waterworks infrastructure and so on, distrust for drinking tap water has been continuing and domestic consumption rate of tap water is in around 5% level and extremely poor comparing to advanced countries such as the United States(56%), Japan(52%), etc. Recently, the water management has been facing the new phase due to water environmental degradation caused by climate change, aging facilities, etc. Therefore, K-water has converted water management paradigm from the "clean and safe water" to the "healthy water" and been pushing the Smart Water City(SWC) Pilot Project in order to develop and spread new water supply models for consumers to believe and drink tap water through systematic water quality and quantity management combining ICT in the whole water supply process. The SWC pilot projects in Pa-ju city and Go-ryeong county were an opportunity to check the likelihood of the "smart water management" as the answer to future water management. It is needed to examine the necessity of smart water management introduction and nationwide SWC expansion in order to improve water welfare for people and resolve domestic & foreign water problems.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.4
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• pp.271-276
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• 2014

The purpose of this study was to survey Suwon citizens over the age of 20 in order to provide basic data on the extent of coverage of the city's water reclamation system and to set guidelines for a policy on water reuse. The survey used a questionnaire with two fields, rainwater use and wastewater recycling, for analyzing factors that influenced water reuse. A factor analysis of 19 questionnaires gave a Cronbach's alpha coefficient greater than 0.4. Factors that influenced rainwater use were environmental protection, water charges, and the risk of climate change. Of the total explanatory power, the share of rainwater use and environmental protection was 39.7% and 28.1% respectively. Environmental protection (explanatory power 24.2%) had an effect on the explanatory power of wastewater reuse. When factors influencing wastewater recycling, like cost of recycling, water management policy, climate change, and suspension of tap water supply were included, the explanatory power of each of these factors went up by 4.3%, 2.8%, 3.3%, and 1.1%, respectively. For more effective wastewater recycling, a water management policy that factors in the above is required, along with a campaign to educate citizens on water management and environment conservation. Additionally, it may be necessary to improve the reliability and the quality of water supply.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.169-169
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• 2023

Most distributed water is not used effectively due to water loss occurring in pipe networks. These water losses are caused by leakage, typically due to high water pressure to ensure adequate water supply. High water pressure can cause the pipe to burst or develop leaks over time, particularly in an aging network. In order to reduce the amount of leakage and ensure proper water distribution, it is important to apply pressure management. Pressure management aims to maintain a steady and uniform pressure level throughout the network, which can be achieved through various operational schemes. The schemes include: (1) installing a variable speed pump (VSP), (2) introducing district metered area (DMA), and (3) operating pressure-reducing valves (PRV). Applying these approaches requires consideration of various hydraulic, economic, and environmental aspects. Due to the different functions of these approaches and related components, an all-together optimization of these schemes is a complicated task. In order to reduce the optimization complexity, this study recommends a sequential optimization method. With three network operation schemes considered (i.e., VSP, DMA, and PRV), the method explores all the possible combinations of pressure management paths. Through sequential optimization, the best pressure management path can be determined using a multiple-criteria decision analysis (MCDA) to weigh in factors of cost savings, investment, pressure uniformity, and CO₂ emissions. Additionally, the contribution of each scheme to pressure management was also described in the application results.

• Journal of Wetlands Research
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• v.24 no.4
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• pp.256-267
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• 2022

This study analyzed the current status and trend of water quality using long-term water quality monitoring data measured over the past 5 years in the Seohwacheon Basin, located upstream of Daecheong Lake. In the Seohwacheon Basin, a project is underway to reduce the occurrence of algal blooms in the Daecheong Lake and to improve water quality, and continuous management is required for water quality management. The current water quality evaluation aims to identify the water quality management point, and the good water grade and the integrated water quality index (WQI) were used. For trend evaluation, the effect of the water quality improvement project was evaluated using the Mann-Kendall test and Sen's Slope. As a result of the evaluation, the current water quality index was used to identify the watersheds and when to manage water quality, and the effect of the improvement project was confirmed through trend analysis. Through this study, it is possible to review the water quality status and improvement effect using long-term water quality monitoring data, so it is expected to be applicable to similar types of watersheds in the future.

• Journal of Korean Society on Water Environment
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• v.26 no.2
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• pp.279-288
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• 2010

The water quality variations or changes are closely relevant to the characteristics of unit watersheds and have an effect on the attainment of their water quality goal. This study was conducted to analyze the water quality distribution and its change patterns of unit watersheds in Nakdong river basin. It revealed that 25 unit watersheds out of 41 showed the normality in water quality. Most of unit watersheds had a considerable variation in water quality, especially in the season of spring and summer but a little in terms of flow rate. Annual relative differences in water quality ranged from 13.0 to 26.6% with the maximum of 75%. 28 unit watersheds (62%) had the tendency to decrease in water quality as the flow rate increased while 13 (38%) to increase. The extension of standard flow led to considerable differences in water quality depending on its ranges, which meant uncertainties might be included in the process of TMDL development. It is suggested that annual average flow rate should be chosen as a standard flow in the area where the water quality change has little relation to the flow rate.

• Environmental Engineering Research
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• v.21 no.1
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• pp.84-90
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• 2016

Regionally the lowest average concentration of TOC was observed with 0.66 mg/L in Nakdong river, while the highest concentration of TOC was observed with 0.91 mg/L in Yeongsan river. The average concentration of TOC for national water quality monitoring site showed that the lowest average concentration of TOC was 1.58 mg/L in Han river, while the highest concentration of TOC was 3.37 mg/L in Yeongsan river. Seasonally, the average concentration of TOC at six upstream sites showed 0.77 mg/L and 0.56 mg/L, 0.69 mg/L and 0.63 mg/L, 0.80 mg/L and 0.73 mg/L, and 1.21 mg/L and 0.68 mg/L between wet season and dry season in Han river, Nakdong river, Gem river and Yeongsan river, respectively. For the national water quality site, the average concentration of TOC between wet season and dry season was 1.70 mg/L and 1.45 mg/L in Han river, 2.01 mg/L and 1.75 mg/L in Nakdong river, 2.01 mg/L and 1.60 mg/L in Gem river, and 3.75 mg/L and 3.00 mg/L in Yeongsan river. The distribution of TOC in upstream and national water quality monitoring sites on four major rivers have been influenced by seasonal and regional characteristics in Korea.

• Korean Journal of Soil Science and Fertilizer
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• v.42
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• pp.102-125
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• 2009