• 상하수도학회지
• /
• 제23권2호
• /
• pp.241-249
• /
• 2009

It is well known that the trend of water demand in large-size water supply systems has been suddenly changed, and many expansions of water supply facilities become unnecessary. To be cost-effective, thus, politicians as well as many professionals lay stress on the adaptive management of water supply facilities. Failure in adapting to the new trend of demand is sure to be the most critical reason of unnecessary expansions. Hence, we try to develop the model and modeling procedure that do not depend on the old data of demand, and provide engineers with the fast learning process. To forecast water demand of Seoul, the Bayesian parameter estimation was applied, which is a representative method for statistical pattern recognition. It results that we can get a useful time-series model after observing water demand during 6 years, although trend of water demand were suddenly changed.

• Environmental Engineering Research
• /
• 제14권4호
• /
• pp.256-260
• /
• 2009

This study used the extensive monitoring datasets of the Korea Ministry of Environment to examine trends in dissolved organic carbon (DOC) in Han River raw water. To estimate the organic contents of water, we adopted allied parameters such as biochemical oxygen demand (BOD) and chemical oxygen demand (COD) as substitutes for DOC. Spatial and temporal analyses were performed on monthly BOD and COD data from 36 monitoring stations (14 for Main Han River, 7 for North Han River and 15 for South Han River) measured from 1989 to 2007. The results of trend analysis indicated that, on the whole, water quality according to BOD showed a downward trend at more than 67% of monitoring stations (9 for Main Han River, 6 for North Han River and 9 for South Han River). However, the water quality of COD showed an upward trend at more than 78% of monitoring stations (8 for Main Han River, 7 for North Han River and 13 for South Han River). The upward trend of COD contrary to the BOD trend indicates that there has been an increase in recalcitrant organic matter in Han River water that is not detectable by means of BOD.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2021년도 학술발표회
• /
• pp.144-144
• /
• 2021

The rapid urbanization in many Asian countries has taken millions of people from the rural countryside to concentrated megacities, which eventually putting pressure on the existing water resources. The over-growing population and increasing living standard of people in the urban region of developed as well as developing countries such as Korea, China, Japan and India have witnessed a drastic change in terms of domestic water demand for the past few decades. In this study, we used the concept of potential surface water availability in the form of surface runoff for future vulnerability assessment. We focused on 42 megacities having population more than 5 million as per the United Nations (UN) census data 2020. The study shows that 30 out of 42 cities having more than 180L/p/d demand for domestic use based on various references. We have predicted the domestic water demand for all the cities on the basis of current per capita demand up to 2035 using UN projected population data. We found that the projected water demand in megacities such as Seoul, Busan, Shanghai, Ghuanzou are increasing because of high population as well as GDP growth rate. On the contrary, megacities of Japan considered in our stud shows less water demand in future due to decreasing trend of population. As per the past records provided by the local municipalities/authorities, we projected different scenarios based on the future supply for various megacities such as Chennai, Delhi, Karachi, Mumbai, Shanghai, Wuhan, etc. We found that the supply to demand ratio of these cities would be below 75% for future period and if such trend continues then the inhabitants will face serious water stress conditions. Outcomes of this study would help the local policy makers to adopt sustainable initiatives on urban water governance to avoid the severe water stress conditions in the vulnerable megacities.

• 한국농공학회:학술대회논문집
• /
• 한국농공학회 2002년도 학술발표회 발표논문집
• /
• pp.37-40
• /
• 2002

It is to show the problems of the existing techniques to estimate agricultural water demand and to suggest the new methods considering the water demand for non-irrigated area and decrease of water loss in canal. It is to suggest the methods to improve the techniques for estimating agricultural water demand and to analyze the water demand and supply according to the facilities capacity. Until now, the concept of per the unit used to estimate agriculture water demand is useful to estimate demand, but is insufficient to cope with the variations of conditions in future. And the paddy area of government is not realistic against a trend of decrease. Water demand decrease is caused by constructions of irrigation facilities as constructing of irrigation canal, but application loss ratio is fixed. Increase of the water demand owing to the increase of the yield per the unit area is also the actual condition which is not considered. The guide-line must contain these contents for a demand estimate.

• 한국물환경학회지
• /
• 제24권4호
• /
• pp.480-487
• /
• 2008

Spatial and temporal analyses of water qualities were performed for 11 monitoring stations located in Mangyung watershed in order to analyze the trends of monthly water quality data of Biochemical Oxygen Demand (BOD), Total Nitrogen (TN) and Total Phosphorus (TP) measured from 1995 to 2004. The long-term trends were analyzed utilizing Seasonal Mann-Kendall test, LOWESS and three-dimensional graphs were constructed with respect to distance and time. The graph can visualize spatial and temporal trend of the long-term water quality in a large river system. The results of trend analysis indicated that water quality of BOD and TN showed the downward trend. This quantitive and quantitative analysis is the useful tool to analyze and display the long-term trend of water quality in a large river system.

• 상하수도학회지
• /
• 제20권2호
• /
• pp.187-196
• /
• 2006

Forecasting the long-term water demand is important in the plan of water supply system because the location and capacity of water facilities are decided according to it. To forecast the long-term water demand, the existing method based on lpcd and population has been usually used. But, these days the trend among the variation of water demand has been disappeared, so expressing other variation of it is needed to forecast correct water demand. To accomplish it, we introduced the System Dynamics method to consider total connections of water demand factor. Firstly, the factors connected with water demand were divided into three sectors(water demand, industry, and population sectors), and the connections of factors were set with multiple regression model. And it was compared to existing method. The results are as followings. The correlation efficients are 0.330 in existing model and 0.960 in SD model and MAE are 3.96% in existing model and 1.68% in SD model. So, it is proved that SD model is superior to the existing model. To forecast the long-term water demand, scenarios were made with variations of employment condition, economic condition and consumer price indexes and forecasted water demands in 2012. After all scenarios were performed, the results showed that it was not needed to increase the water supply ability in Seoul.

• 상하수도학회지
• /
• 제20권4호
• /
• pp.527-534
• /
• 2006

Demand side management(DSM) is the newly raised issues in the water resources management in recent. Many of the policy tools among demand management, the most important measures might be a pricing system. Furthermore, the responses of consumers on the price for water consumption level is the key factor for policy making. Here, we estimated panel data for 167 regions and over 7 years periods in Korea. Compare to other previous studies the price elasticities were somewhat low. The estimated price elasticity was -0.05. It was because the short term estimated period may derive lower elasticities. However, it might be a recent trend after the continuous increment of water pricing and consumers not willing to decrease their residential water consumption with increasing water pricing. According to this results, water saving effect might be much smaller than we expect with pricing policy. However, It does not imply there is no price effects on water consumption and it's still meaningful as a tool of water management.

• 물과 미래
• /
• 제27권4호
• /
• pp.135-143
• /
• 1994

본 연구에서는 상수도 급수량의 시간적 변화형태를 조사하고, 수요량의 시간적인 변화량에 통계학적 개념을 이용하여 수요량의 시간적 변화에 관한 확률적 분산모형에 관하여 검정 결정하였다. 연구대상의 지역으로 광주시를 선정하고, 자료로는 2시간 간격으로 측정된 배수지의 수위와 1일 상수도 생산량을 이용하였다. 급수계통의 모형에 통제용적과 연속방정식을 적용하여 2시간별로 변화되는 수요량을 결정하고, 매월 단위로 정리하여 수요수량의 변화를 알 수 있도록 하였다. 2시간별 수요수량은 1일 총 급수량에 대한 백분율로 환산하여 지수화하였으며, 시간별로 변화되는 각각의 급수량은 통계학적으로 추론될 수 있는지 알 수 있도록 분산모형에 관하여 검정을 하였다. 검정결과를 이용하면 시간별 확률 급수량의 산정이나 급수량의 통계학적 해석을 통하여 상수도 시설의 운용에 이용할 수 있는 것으로 판단되었다.

• 상하수도학회지
• /
• 제23권1호
• /
• pp.57-67
• /
• 2009

Under the supply-oriented policy, efficiency and rationale have not been fully considered in planning of water supply facilities in Korea. As a case, this study shows that large-size systems are suffering from overcapacity problem of water treatment plants, and thus discusses what options should be applied to deal with inefficiency. Water demand of large-size systems has suddenly decreased for the last 10 years while water demand has been often assumed to increase at a regular rate in planning of plants according to excess capacity hypothesis. This inconsistency led to a serious overcapacity. In 2006, total excess capacity of nine large-size systems was more than 1.2 times as large as maximum daily demand of total customers in Seoul. However, their options are expected to stay ex post facto. To prepare the risk of overcapacity, and draw large benefits out of the plants, the authors and other professionals in Korea should further discuss the more adaptive method for prediction of water demand, and systems integration between a large-size system and adjoining systems.

• 한국물환경학회지
• /
• 제27권2호
• /
• pp.178-187
• /
• 2011

National water supply, water resources available, the ratio of water supply to total water resources, and the ratio of water supply to available water resources were investigated to find global seawater desalination plant market for 163 nations. Water resources available per capita from 2007 to 2016, population in water scarcity region from 2011 to 2016, and the ratio of water scarcity population to total population were also analyzed for the countries. Annual percentage increase in total municipal drinking water capital expenditure and Annual percentage increase in total industrial water market were analyzed to predict the amount of water supply by use. 76 countries are suffering from water scarcity and 60 countries among the countries have coastal regions. Forty countries were selected by considering the considerable amount and highly increasing trend of water demand by use. Most countries show increasing trend of industrial water and 82 countries have more than 4% annual increasing rate for domestic water expense from 2008 to 2016 among 163 countries. Among the 76 water scarcity countries 16 countries were finally selected by considering expense prediction by use. Middle-east, east asia, pacific ocean, and west europe regions include most selected countries.