• Journal of Soil and Groundwater Environment
• /
• v.23 no.1
• /
• pp.92-105
• /
• 2018

In this study, the projected land use area in 2030 for major crop production was estimated in Jeju Island using land cover map, and corresponding agricultural water demand for 40 sub-regions was quantitatively assessed using the future climate change scenario (RCP 4.5). Estimated basic unit of water demand in 2030 was the highest in the western region, and the lowest in the eastern region. Monthly maximum agricultural water demand analysis revealed that water demand in August of 2030 substantially increased, suggesting the climate of Jeju Island is changing to a subtropical climate in 2030. Agricultural water demand for sub-region in 2030 was calculated by multiplying the target area of the water supply excluding the area not in use in winter season by the basic unit of water demand, and the maximum and minimum values were estimated to be $306,626m^3/day$ at Seogwipo downtown region and $77,967m^3/day$ at Hallim region, respectively. Consequently, total agricultural water demand in Jeju Island in 2030 was estimated to be $1,848,010m^3/day$.

• Environmental and Resource Economics Review
• /
• v.9 no.4
• /
• pp.621-639
• /
• 2000

High population and economic growth leads to ever increasing demand for water resources, prompting many regional conflicts for the water. With the observation, this paper examines the allocation problem of flowing water between upstream and downstream regions, We offer a two- region model in which the downstream region pays a portion of product to the upstream region in order to induce the upstream region to share the water. Our model shows that the "side-payment" does not always work, because the ex post income of the downstream region could be lower than the income without the side-payment This happens when the externality the upstream region imposes on the downstream region is small. The paper derives the condition under which the incentive mechanism like side-payment is likely to fail (or work). The model also shows that the higher the degree of externality is, the less amount of side-payment should be. The results of the paper suggest that the incentive scheme can help the regional conflicts be solved if the externality effect generated by the water use of upstream region is big enough, which is in fact the case where the conflict is severe.

• Journal of Korean Society on Water Environment
• /
• v.27 no.2
• /
• 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.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1998.10a
• /
• pp.279-286
• /
• 1998

The south-western part of Korea is situated in an unbalance of water supply and demand relating to the Keum, Mankyung, Dongjin and Youngsan River and their estuary reservoirs. For example, the Keum River estuary reservoir is discharging the larger amount of yearly runoff into the sea due to the small storage capacity, while Saemankeum estuary reservoir which is under construction, has the smaller runoff amount comparing with its storage capacity, And the downstream area of the Youngsan River, such as Youngkwang, Youngam are deficient in water due in larger demand and smaller supply. In order to solve the above unbalanced water supply and demand and also to improve the water use efficiency, the Hierarchical Operation Model for Multi-reservoir System(HOMMS) has been developed and applied to analyze the multi-reservoir operation assuming that the above reservoirs were linked each other. The result of this study shows that 2,148MCM of annual additional water requirement for agricultural and rural water demands are required in this region at 2011 of target year, and these demands can be resolved by diverting and reusing 1,913MCM of the released water from the estuary reservoirs into the sea.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2022.05a
• /
• pp.156-156
• /
• 2022

Explicitly spatially distributed and reliable data on industrial water demand is very much important for both policy makers and researchers in order to carry a region-specific analysis of water resources management. However, such type of data remains scarce particularly in underdeveloped and developing countries. Current research is limited in using different spatially available socio-economic, climate data and geographical data from different sources in accordance to predict industrial water demand at finer resolution. This study proposes a random forest regression (RFR) model to predict the industrial water demand at 0.50× 0.50 spatial resolution by combining various features extracted from multiple data sources. The dataset used here include National Polar-orbiting Partnership (NPP)/Visible Infrared Imaging Radiometer Suite (VIIRS) night-time light (NTL), Global Power Plant database, AQUASTAT country-wise industrial water use data, Elevation data, Gross Domestic Product (GDP), Road density, Crop land, Population, Precipitation, Temperature, and Aridity. Compared with traditional regression algorithms, RF shows the advantages of high prediction accuracy, not requiring assumptions of a prior probability distribution, and the capacity to analyses variable importance. The final RF model was fitted using the parameter settings of ntree = 300 and mtry = 2. As a result, determinate coefficients value of 0.547 is achieved. The variable importance of the independent variables e.g. night light data, elevation data, GDP and population data used in the training purpose of RF model plays the major role in predicting the industrial water demand.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.66 no.3
• /
• pp.25-37
• /
• 2024

Global warming-induced drought inflicts significant socio-economic and environmental damage. In Korea, the persistent drought in the southern region since 2022 has severely affected water supplies, agriculture, forests, and ecosystems due to uneven precipitation distribution. To effectively prepare for and mitigate such impacts, it is imperative to develop proactive measures supported by early monitoring systems. In this study, we analyzed the spatiotemporal changes of multiple evapotranspiration-based drought indices, focusing on the flash drought event in the southern region in 2022. The indices included the Evaporative Demand Drought Index (EDDI), Standardized Precipitation Evapotranspiration Index (SPEI) considering precipitation and temperature, and the Evaporative Stress Index (ESI) based on satellite images. The Standardized Precipitation Index (SPI) and SPEI indices utilized temperature and precipitation data from meteorological observation stations, while the ESI index was based on satellite image data provided by the MODIS sensor on the Terra satellite. Additionally, we utilized the Evaporative Demand Drought Index (EDDI) provided by the North Oceanic and Atmospheric Administration (NOAA) as a supplementary index to ESI, enabling us to perform more effective drought monitoring. We compared the degree and extent of drought in the southern region through four drought indices, and analyzed the causes and effects of drought from various perspectives. Findings indicate that the ESI is more sensitive in detecting the timing and scope of drought, aligning closely with observed drought trends.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2021.06a
• /
• 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.

• Journal of Environmental Science International
• /
• v.31 no.1
• /
• pp.33-42
• /
• 2022

The objective of this study is to determine the appropriate size of the inlet pipe diameter and thereby conduct hydraulic analysis for the Korean water distribution network. To this end, the data tables for equivalent pipe diameters and outflow rates presently employed in Korea were adopted. By incorporating the table of equivalent pipe diameters, it was found that the size of the inlet pipe diameter was overestimated, which can cause shortage of water pressure and malfunctioning or insufficiency of outflow rate in the corresponding adjacent region. However, by conducting hydraulic analysis based on the table of outflow rates, relatively reasonable flow rates were observed. Furthermore, by comparing the real demand-driven analysis (RDDA) approach and demand-driven analysis (DDA) approach toward managing the huge water demand, it was observed that DDA could not effectively respond to real hourly usage conditions, whereas RDDA (which reflects the hourly effects of inlet pipe diameter and storage tanks) demonstrated results similar to that of real water supply.

• Journal of Environmental Science International
• /
• v.25 no.3
• /
• pp.447-456
• /
• 2016

Access to clean and affordable water is one of the fundamental human rights because water is essential to life and a foundation for socioeconomic development of any country in the world. Despite the efforts to secure water supply in Burundi, the amount of water supplied by public utilities does not meet the demand of the population because population keeps increasing with fluctuation of weather conditions. This study selected north Bujumbura that is a sprawling new residential area in the western part of Burundi as a case to investigate the potential of rainwater harvesting in meeting water demand of the country. Based on a long-term average monthly precipitation in the region, the rainwater harvesting potential was assessed as a function of roof sizes, number of households, and runoff coefficients of roof materials. For the entire region of north Bujumbura, the current water supply capacity of the local water company combined with the rainwater harvesting potential resulted in the water surplus of $468,604.1m^3/yr$. Although three communes among them still showed water deficit in dry season, they still got help from rainwater to relieve their water shortage. This suggests that at the regional scale, proper storages and water quality control for harvestable rainwater could contribute to relieving the regional water shortage and allow the population growth.

• Journal of Environmental Science International
• /
• v.22 no.5
• /
• pp.639-649
• /
• 2013

Over 96.2% of the agricultural water in Jeju Island is obtained from groundwater and there are quite distinct characteristics of agricultural water demand/supply spatially because of regional and seasonal differences in cropping system and rainfall amount. Land use for cultivating crops is expected to decrease 7.4% (4,215 ha) in 2020 compared to 2010, while market garden including various vegetable crop types having high water demand is increasing over the Island, especially western area having lower rainfall amount compared to southern area. On the other hand, land use for fruit including citrus and mandarin having low water demand is widely distributed over southern and northern part having higher rainfall amount. The agricultural water demand of $1,214{\times}10^3\;m^3/day$ in 2020 is estimated about 1.39 times compared to groundwater supply capacity of $874{\times}10^3\;m^3/day$ in 2010 with 42.4% of eastern, 103.1% of western, 61.9% of southern, and 77.0% of northern region. Moreover, net secured amount of agricultural groundwater would be expected to be much smaller due to regional disparity of water demand/supply, the lack of linkage system between the agricultural water supply facilities, and high percentage of private wells. Therefore, it is necessary to ensure the total net secured amount of agricultural groundwater to overcome the expected regional discrepancy of water demand and supply by establishing policy alternative of regional water supply plan over the Island, including linkage system between wells, water tank enlargement, private wells maintenance and public wells development, and continuous enlargement of rainwater utilization facilities.