• Journal of environmental and Sanitary engineering
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• v.2 no.2 s.2
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• pp.69-78
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• 1987

Due to the increase of population and development of industry, the demand of available water resources increased . Many reservoirs have been constructed in large scales to meet this urgent need , resulting in the increased amount of water resources. After the constructions, however, serious pollution-especially eutrophication-in some reservoirs become a socialaffair. Therefore, water quality control in these resources should be considered more intensively than any other environmental preservation policies. It also seems to be imminent to prepare the precautionary steps. Most water pollution in Korea-73 percent - can be traced to domestic sewage. It may rome as a surprise to Some, Industry is responsible for just 27 percent of ]Korea's water pollution. What he calls 'non-point' Sources, which may include agricultural Chemicals, Create only negligible amount of water pollution. Up to $15\%$ of domestic sewage is treated in Korea, which is quite low when compared with the waste processing in developed countries. So it is the most urgent matter to control the pollution sources. One of the precautionary plans, more urban domestic sewage treatment plants must be installed and operated efficiently. It is known that nutrients such as nitrogen and phosphorous are the major factors the process of eutrophication, which can be removed majorly by the tertiary or advanced treatment process.

• Journal of Internet Computing and Services
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• v.20 no.6
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• pp.47-54
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• 2019

Social dredging of various river facilities, such as dams and agricultural reservoirs currently being constructed, should be done to ensure stable reservoirs. However, it is difficult to find a system that tells the exact amount of water in real-time in a reservoir or dam. These measurements require an automated system to collect and analyze highly accurate data in real time. In this study, we propose a method to measure the amount of water and soil of reservoir in real time through multi-division volume calculation using a drone, and this method can detect sediment conditions in real time and determine the exact timing and scale of dredging.

• Journal of Ecology and Environment
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• v.30 no.3
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• pp.237-244
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• 2007

We investigated the foraging habitat preferences of herons and egrets in an agricultural area in Asan city, Chungcheongnam-do, Korea. In the study area, rice fields were the most abundant habitat type (86.8%) and total suitable feeding habitat was greater in the northern area (59.0%) than the southern area (22.5%) of the colony. Most feeding herons and egrets were located in the northern area of the colony. The number of feeding individuals in a given area was related to the available feeding area (Pearson correlation, r=0.773, p<0.001 for field habitats; r=0.901, p<0.001 for freshwater habitats). Feeding habitat preferences differed among species. Grey herons (Ardea cinerea), great egrets (Egretta alba), and black-crowned night herons (Nycticorax nycticorax) used reservoirs and ditches. However, intermediate egrets (E. intermedia) and cattle egrets (Bubulcus ibis) were dependent on rice fields. The little egret (E. garzetta) was a habitat generalist using all types of habitats. The two largest species, grey herons and great egrets, fed at deeper site than little egrets and foraged in deeper sites in reservoirs than in ditches (${\chi}^2-test,\;{\chi}^2{_3}=26.6$ and p<0.001 for grey herons, ${\chi}^2{_3}=17.5$ and p<0.001 for great egrets). All species displayed seasonal changes in feeding habitat use and these changes were related with changes in availability of feeding habitats.

• Journal of Environmental Science International
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• v.29 no.11
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• pp.1099-1108
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• 2020

In this study, the capacity of supplying agricultural water to 13 districts was analyzed by calculating the necessary water supply for the arable land of Gunwi-gun and examining the capacity of supplying water to reservoirs, streams, pumping stations, collection sites, and groundwater wells in Gunwi-gun. As a result, among the 13 districts the second district was found to be short of water by 1.2×10⁶ tons/year. In general, local governments establish drought measures by selecting drought disaster risk zones. While selecting drought-risk areas, some water-poor areas that do not have water sources should be selected, even if the entire area has a sufficient water supply. The water-supply evaluation at the regional level was insufficient for locating areas without water sources, but most areas with water sources, such as streams, reservoirs, and pumping stations, were found to have no shortage of water. To locate water shortage areas without water sources, GIS analysis conducted a field survey of areas with a distance of 4 or less than that of water sources analyzed by GIS analysis. Sixty-nine sites in 13 districts were selected for the on-site survey and six areas of water shortage were identified in areas other than the second district.

• Journal of Korean Society of Rural Planning
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• v.24 no.4
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• pp.47-55
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• 2018

Currently in the drought evaluation, which is a supplier-oriented standard that applies storage rates of reservoirs, evaluation for users that use agricultural water is not done. Therefore, this study established drought evaluation items for drought evaluation based on farmers' judgement, conducted a survey on farmers and experts, compared and analyzed weighted value between two groups, and then classified the evaluation standards per each evaluation item. The agricultural drought evaluation items are 5 major items of water supply lapse rate, agricultural weather, agricultural irrigation facility, crop and soil, and 12 subsections for regional characteristics and opinions of consumers that use water to be reflected. The result of analyzing weighted value of farmers and experts' major items shows that farmers is agricultural irrigation facility(0.219), water supply lapse rate(0.211), agricultural weather(0.204), crop(0.183) and soil(0.183). Experts is agricultural weather(0.297), agricultural irrigation facility(0.202), water supply lapse rate(0.189), crop(0.162) and soil(0.150), which displays difference between the two groups. The agricultural drought criteria standards are established based on precedent studies and cases, and grades of evaluation items are 1st grade(extreme stage), 2nd grade(warning stage), 3rd grade(alert stage) and 4th grade(attention stage). The above analysis per each consumer-oriented agricultural drought evaluation item and the analysis on the standards of evaluation grades are expected to be used as a basic resource for establishing agriculture drought policy and selecting drought area in the future.

• Magazine of the Korean Society of Agricultural Engineers
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• v.42 no.1
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• pp.73-82
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• 2000

Large quantitive of polllutants are washed into reservoirs during storm events. These polllutants contribute to eutrophication, such as algal blooms and fish kills. This study was conducted for the purpose of assessing the pollutant removal possibilities of sedimentation pool formed by deep dredging of a reservoir inlet. Water quality data were collected in the Masan reservoir, whose inlet has been dredged deep like sedimentation pool. The average concentration of chemical oxygen demand(COD) , toatal nitrogen(T-N) and total phosphrous(T-P) in the deep dredged area were 8.7 ~20.5mg/ι (T-N), 0.17~0.84mg/ι(T-P), which were 4.9%(COD), 29.0%(T-N) and 44.8%(T-P) higher than those of middle part of the reservior. The texture of sediment in the dredged area was silty loam, while that of the middle part was sandy clay loam. Organic matter contents, T-N and T-P of the bottom soil in the dredge area showed higher values than the middle part of the reservoirs. From these results, it was considered thedeep dredged area in the inlet of reservoir might play a key role to settle pollutant particulate. Based on the result of water quality analysis, deep dredging of the reservoir inlet could be assessed to reduce T-N and T-P of the reservoir about 6.5% , 8.3%, respectively. However, the effect of the sedimentation pool would be raised if the settled particles were taken into account in assessing water quality improvement for the reservoir. Accordingly, dredging of a reservoir inlet to make a shape of sedimentation pool is recommended for water quality improvement of reservoir in the stage of dredging plan.

• Journal of the Korean Geographical Society
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• v.38 no.4
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• pp.535-561
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• 2003

The Kyodong Island on the Yellow Sea has experienced dramatic transformations in the process of massive reclamations of tidal flats. Consisting originally of detached several islets, Kyodong became an integrated island country with the establishment of sea dikes across the salt marshes. The coastal plaines passed through four distinct stages of development. During the nascent period from the Early States to the Koryo Dynasty, strategic considerations led up to the establishment of causeways and garrison farms as well as private land plots. The relocation of regional headquarters of the navy into the island made the reclamation of tidal flats a systematic project during the period of Chosun Korea. The implantation of a large-scale estate by Japanese capitalists was the most characteristic feature of this region's geography during the colonial period. Present-day Kyodong displays various agrarian landscapes of standardized land plots, reinforced sea dikes, and automated agricultural machinery. Throughout the periods irrigation systems have sustained the panoramic transformation of the agricultural geographies of the Kyodong Island. The local people afflicted by a chronic deficiency of water came up with ingenuous irrigation systems such as springs, paddy reservoirs, reservoirs, tanks, artesian wells, and pump stations.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.4
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• pp.73-84
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• 2015

An embankment raising project on 113 agricultural reservoirs in Korea was implemented in 2009 to increase water supply capacity for agricultural water and instream uses. This study evaluated the future water supply capacity of the Imgo reservoir at which the agricultural reservoir embankment raising project was completed, considering climate change scenarios. The height of the embankment of the reservoir was increased by 4.5 m, thereby increasing its total storage from 1,657.0 thousand to 3,179.5 thousand cubic meters. To simulate the reservoir water storage with respect to climate changes, two climate change scenarios, namely, RCP 4.5 and RCP 8.5 (in which greenhouse gas reduction policy was executed and not executed, respectively) were applied with bias correction for reflecting the climate characteristics of the target basin. The analysis result of the agricultural water supply capacity in the future, after the agricultural reservoir embankment raising project is implemented, revealed that the water supply reliability and the agricultural water supply increased, regardless of the climate change scenarios. By simulating the reservoir water storage considering the instream flow post completion of the embankment raising project, it was found that water shortage in the reservoir in the future is not likely to occur when it is supplied with an appropriate instream flow. The range of instream flow tends to decrease over time under RCP 8.5, in which the greenhouse gas reduction policy was not executed, and the restoration of reservoir storage was lower in this scenario than in RCP 4.5, in which greenhouse gas reduction policy was executed.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.213-214
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• 2005

Uiryung Watershed area, located at the confluence of Nam River and Nagdong River has 9000 ha of agricultural land area and 3024 ha of paddy rice field have been reclaimed and managed by Korean Agricultural and Rural Infrastructure Corporation(KARICO) in the riparian area since 1954. In spite of irrigation and drainage improvement projects in last 3 decades since 1970, there are severe drought and innundation problems in the area. To improve the difficulties and efficient usage of irrigation water not only for agriculture but also for environmental conservation and cultural ceremony, Automatic Water management system has been installed supported by Ministry of Agriculture and Fishery in Korean Government. The control office in Uiryung Branch Office of KARICO, receive all the water management records from Remote Terminal Units in 7 reservoirs and 26 Pump stations to operate the decision supporting system of irrigation and drainage facility during cropping period. Since the completion of the water management system at the end of 2003, the electric cost decrease in 80 % than average years. In spite of decrease of two technical assistants since 2004, complains from farmers for the water management are very rare. The technological experience from the automatic water management system would contribute not only for the efficient water management of Uiryang area but also for the modernization of water management of other watershed areas in the future.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.4
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• pp.45-53
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• 2013

Efficient water operation and management of an irrigation system plays an important element in the sustainability of irrigated agriculture. An agricultural water is delivered in many open canals of irrigation delivery system by reservoirs. The poor water distribution and management in an irrigation system is a major factor leading to low water efficiency. It is necessary to compare the estimated irrigation demands with the actual water supplies for decision making to maintain the water supply according to demand strategy. Smarter water management, new technologies and improvement of water management system, is essential to solve the problem of water efficiency and availability. In this paper, the irrigation efficiencies according to water delivery performance indicator were measured with automatic water gauge at irrigation canals, and calculated from spatial and temporal distribution of water supply for the lack of planning in water delivery. The analysis of results are obtain an insight into possible improvement methods to develop canal water management policies that enable irrigation planners to optimally manage scarce available water resources.