• Journal of Korean Society on Water Environment
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• v.30 no.1
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• pp.31-43
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• 2014

Recently, Andong Reservoir and Imha Reservoir located in Nakdong River basin (Korea) are being connected by a tunnel (length 2km, diameter 5.5m) for a conjunctive use. The objectives of this study were to construct a two dimensional(2D) laterally-averaged model for two reservoirs, and examine the effects of connection on the water transportation and temperature stratification in the reservoirs. The 2D models for each reservoir were calibrated using field data obtained in 2006, and applied to the linked system for the year of 2002 when a severe flood intruded into Imha Reservoir during the typhoon Rusa. Simulation results showed that 364 million $m^3$ of water can be conveyed from Imha to Andong, while 291 million $m^3$ of water from Andong to Imha after connection. It resulted in 1.38 m increase of annual averaged water level in Andong Reservoir, whereas 3.75 m decrease in Imha Reservoir. The structures of thermal stratification in both reservoirs were influenced in line with the flow exchanges. In Andong Reservoir, the location of thermocline moved upward about 10 m compared to an independent operation. The results imply that the persistent turbidity issue of Imha Reservoir might be shifted to Andong Reservoir during a severe flood event after connection.

• Magazine of the Korean Society of Agricultural Engineers
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• v.24 no.1
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• pp.44-52
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• 1982

Recently, estuary reserovoirs have been actively constructed in Korea and also in Japan there are a large number of estuary reservoirs constructed. But most of the estuary reservoirs are located at the downstream of a river where geographical condition is best for the construction of an enclosing dam. And an effective utilization of water from the estuary reservoir seems to be difficult even if estuary reservoirs are considered to be the water resources the most available for their watershed. Studies on estuary reservoirs so far have been mainly concentrated on the physical and engineering problems of the dam construction itself. The purpose of the present study is to review the estuary reservoir planning in connection with the water resources development and to study a basis of the planning. First, the levels of water use in Korea and Japan were compared with those of other countries in the world. And then, some representative reservoirs were selected to study the roles of a reservoir and water-using conditions in the watershed. Based on the study, a survey was given on the relation between a dam construction upstream and an estuary reservoir construction downstream of a river. Finally, a comprehensive examination was made of the bases of estuary reservoir planning. (1) The estuary reservoir planning is deeply related to the plan for water use develo- pment in the watershed. After the upstream water resources were fully developed up to the most, water reso- urces development by an estuary reservoir should be started. (2) If an estuary lake has a capacity big enough, it can store flood discharge of the watershed without any loss and become a basic facility that will bring about the maxi- mum use of water from the watershed. (3) Estuary reservoirs store water used in the upstream watershed, so recycling of water use is attained by the reservoir. Water in the estuary lake is difficult to be fresh water in its long run. Therefore, estuary reservoir should be located at a place where polluted water is purified and refused. All the planning should be based on the assumption that water in the estuary lake is not fresh but polluted after a long time. (4) The estuary lake can only supply water to the lower basin directly. But the upstream area is benefited from the estuary lake by exchange of irrigation water sources between the lower and the upper area. So a large-scale exchange plan between new and existing water resources is important. By constructing estuary reservoirs and the exchange of water sources between upper and lower areas, the reasonable maximum use of water from the whole watershed is at- tained. (5) The big problem coming from the water resources development by an enclosing estuary is salt water intrusion into the lake. To maintain the estuary lake salt-free, multi-purpose use of the lake should be avoided. It is necessary to take such fundamental measures as abolition of back flow operation of gate, and the closing of the fish port and the fish ladder. The results mentioned above were found in this study and these results of this study could be used for the adequate planning of estuary reservoirs in connection with the maximum water use of the watershed.

• Journal of the Korean Professional Engineers Association
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• v.3 no.10
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• pp.7-17
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• 1970

Fourteen reservoirs maintained by the local land improvement associations in the province of Chullabuk-Do and 20 reservoirs maintained by those in the province of Chullanam-Do, were surveyed in connection with a correction between storage capacity and sediment deposit. In addition to this survey, 3347 of small scale reservoirs, that lie scattered around in the above mentioned two provinces were investigated by using existing records pertaining to storage capacity in the office of City and Country, respectively. According to this inrestigation. the following conclusions are derived. 1. A sediment deposition rate is high, being about 10.63m$^3$/ha of drainage area, and resulting in the average decrease of storage capacity by 27.5%. This high rate of deposition could be mainly attributed to the severe denudation of forests due to disorderly cuttings of trees. Especially, in small scale reservoirs, an original average design storage depth of 197mm in irrigation water depth is decreased to about 140mm. 2. An average unit storage depth of 325.6mm as the time of initial construction is decreased to 226mm at present. This phenomena causes a greater shortage of gation water, since it was assumed that original storage quantity itself was already in short.

• Magazine of the Korean Society of Agricultural Engineers
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• v.29 no.3
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• pp.125-137
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• 1987

The purpose of this paper is to examine some difficulties in water management of agricultural reservoirs in Korea, for there are approximately more than 15,000 reservoirs which are now being utilized for the purpose of irrigation, along with the much amount of expenses and labors to be invested against droughts and floods periodically occurred. Recently, the effective use of water resources in the agricultural reservoirs with a single purpose, is becomming multiple according to the alterable environment of water use. Therefore, the task to allocate agricultural water rationally and economically must be solved for the multiple use of agricultural reservoirs. On the basis of the above statement, this study aims at suggesting the rational method of water management by introducing an optimal technique to allocate the water in an existing agricultural reservoir rationally, for the sake of maximizing the economic effect. To achieve this objective, a reservoir, called "0-Bongje" as a sample of the case study, is selected for an agricultural water development proiect of medium scale. As a model for the optimum allocation of water in the multi-purpose use of reservoirs a linear programming model is developed and analyzed. As a result, findings of the study are as follows : First, a linear programing model is developed for the optimum allocation of water in the multi-purpose use of agricultural reservoirs. By adopting the model in the case of reservoir called "O-Bongje," the optimum solution for such various objects as irrigation area, the amount of domestic water supply, the size of power generation, and the size of reservoir storage, etc., can be obtained. Second, by comparing the net benefits in each object under the changing condition of inflow into the reservoir, the factors which can most affect the yearly total net benefit can be drawn, and they are in the order of the amount of domestic water supply, irrigation area, and power generation. Third, the sensitivity analysis for the decision variable of irrigation which may have a first priority among the objects indicate that the effective method of water management can be rapidly suggested in accordance with a condition under the decreasing area of irrigation. Fourth, in the case of decision making on the water allocation policy in an existing multi-purpose reservoir, the rapid comparison of numerous alternatives can be possible by adopting the linear programming model. Besides, as the resources can be analyed in connection with various activities, it can be concluded that the linear programing model developed in this study is more quantitative than the traditional methods of analysis. Fifth, all the possible constraint equations, in using a linear programming model for adopting a water allocation problem in the agricultural reservoirs, are presented, and the method of analysis is also suggested in this study. Finally, as the linear programming model in this study is found comprehensive, the model can be adopted in any different kind of conditions of agricultural reservoirs for the purpose of analyzing optimum water allocation, if the economic and technical coefficients are known, and the decision variable is changed in accordance with the changing condition of irrigation area.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.163-168
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• 2016

For the quality increase of agricultural and aquatic products, it is necessary to the efficient management system of integrated control and accurate data for improving the water quality of reservoirs. This may be using the USN save time and money. In this paper, the water surface robot was designed and manufactured for measuring and announcing the environment informations, and it's network was constructed. The robot had more excellent durability and was more inexpensive than previous model. The network was designed considering connection with ZigBee, TRS, Wi-Fi or LTE network. Also the exploration function of the robot was confirmed by the simulation and the user interface was programmed.

• Journal of Wetlands Research
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• v.23 no.2
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• pp.189-200
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• 2021

To improve the water quality of agricultural reservoirs, constructed wetlands are applied in many places. These are technologies that establish ecosystems and important design factors include water depth distribution, inflow and outflow, water flow distribution, hydraulic residence time, water quality treatment efficiency, aspect ratio, and the distribution of open water and covered water surfaces. For high efficiency during the operation of a constructed wetland, the design needs to be optimized and this requires consideration of the different types and length of the intake dam as well as the type and connection of wetland cells. Therefore, this study was conducted to investigate and suggest factors that needs to be considered during the design and for efficient operation measures through field surveys of 23 constructed wetlands that have been established and operated in agricultural reservoirs. Results of the field investigation shows that several sites were being operated improperly due to the malfunctioning or failure of the water level sensors, sedimentation in the intake dam, and clogging of the mechanical sluice frames. In addition, it was found that as the length of the inlet channel increases, the ecological disconnection between the intake dam upstream and the wetland outlet downstream also increases and was identified as a problem. Most of the wetlands are composed of 2 to 5 cells which can result to poor hydraulic efficiency and difficulty in management if they are too large. Moreover, it was found that the flow through a small wetland can be inadequate when there are too many cells due to excessive amounts of headloss.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.3
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• pp.101-108
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• 2015

The purpose of this study was to evaluate the safety of the small reservoir, which is distributed in a rural area, based on systemic reliability. It has been estimated that safety of respective reservoir the calculation of failure probability for individual reservoirs can evaluate the safety of the reservoir of the study area. The change of safety for watershed could be figured out as that result. Probability of failure was increased from $3.90{\times}10^{-5}$ to $1.35{\times}10^{-4}$ in Naesu-inpyung reservoir, from $1.33{\times}10^{-5}$ to $4.77{\times}10^{-5}$ in Buyeon reservoir and from $4.24{\times}10^{-5}$ to $2.55{\times}10^{-2}$ in Dalakmal respectively. From the results, the collapse of the upper stream reservoir was analyzed qualitatively that may affect the safety of the reservoir on the downstream area.

• Korean Journal of Environmental Agriculture
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• v.19 no.3
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• pp.252-258
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• 2000

SWMM and WASP5 were applied for pollutant loading estimate from watershed and reservoir water quality simulation, respectively, to predict estuarine reservoir water quality. Application of natural systems to improve estuarine reservoir water quality was reviewed, and its effect was predicted by WASP5. Study area was the Hwa-Ong reservoir in Hwasung-Gun, Kyonggi-Do. Procedures for estimation of pollutant loading from watershed and simulation of corresponding reservoir water quality were reviewed. In this study, SWMM was proved to be an appropriate watershed model to the nonurban area, and it could evaluate land use effects and many hydrological characteristics of catchment. WASP5 is a well known lake water quality model and its application to the estuarine reservoir was proved to be suitable. These models are both dynamic and the output of SWMM can be linked to the WASP5 with little effort, therefore, use of these models for reservoir water quality prediction in connection was appropriate. Further efforts to develop more logical and practical measures to predict reservoir water quality are necessary for proper management of estuarine reservoirs.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.12
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• pp.1815-1819
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• 2009

Based on the soft and rigid extents, tissues are mainly divided into two groups in mammals, soft tissues including heart, lung, kidney and brain, and hard tissues including tendon, cartilage, teeth and bone. Among various tissues, bone, a dynamic rigid organ, is continuously remodeled by the opposing functional activity between bone formation by osteoblasts and bone destruction by osteoclasts. Bone protects the soft tissues and provides mineral reservoirs, which can supply the mineral needs of other soft tissues to normally maintain cellular function. While calcification in bone is an important action to fundamentally support the body and protect the soft tissues, calcification in soft tissues, including the heart, aorta, kidney, lung and spleen, results in severe organ damages, eventually causing sudden death. A growing body of evidence indicates that the osteoporotic patient who are aging, post-menopausal, diabetes and chronic kidney disease simultaneously represent a high clinical incidence of soft tissue calcification, illustrating a link between soft tissue calcification and bone decalcification (osteoporosis). This study will review what is currently known about the connection between bone decalcification and soft tissue calcification.

• Magazine of the Korean Society of Agricultural Engineers
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• v.13 no.2
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• pp.2262-2275
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• 1971

Fourteenes rervoirs maintained by the local land improvement associations in the province of Chullabuk-Do and 20 reservoir maintained by thos in the province of Chullanam-Do, were surveyed in connection with a correction between storage capacity and sediment deposit. In addition to this survey, 3,347 of small reservoir, that lie scattered around in the above-mentioned two provinces were investigated by using existing two provinces were investigated by using existing records pertaining to storage capacity in the office of City and country, respectively. According to this investigation the following comclusions are derived. 1. A sediment deposition rate is high, being about $10.63m^3/ha$ of drainage area, and resulting in the average decreasc of storage capaity by 27.5%. This high rate of deposition coule be mainly attributed to the serve denudation of forests due to disorderly cuttings of trees. Easpecially, in small reservoir, an original average design storage depth of 197mm in irrigation water depth is decreased to about 140mm. 2. An average unit storage depth of 325.6mm as the time of initial construction is decreased to 226mm at present. This phenomena causes a greater shortage irrigation water, since it was assumed that original storage quantity was already in short. 3. Generally speaking, seepage rates through dam abutment intakepipe, etc, are high due to insufficient maintenance and management of reservoir. 4. It is recommended that sediment deposit should be dredged when a reservoir is dry in drought. 5. Farmers usually waste excessive irrigation water. 6. Water saving methods should be practiced by applying only necessary water for growing stage of rice. 7. In are as where water defficiency for irrigation is severe, a soil moisture content should be kept at about 70% by applying water once in several days. 8. Tube wells should be provided so as to exploit ground water and subsurface current below stream bed as much as possible. 9. If an intake weir was constructed, a water collection well should be built for the use in drought. 10. Water conservation should be forced by converting devastated forests contained in the drainage area of reservoir to protected forests so as to take priority of yrefor estation, gully control, the prohibition of disorderly cutting of trees, etc. 11. Collective rice nurseries should be adopted, and it should be recommended that irrigation water for rice nurseries is supplied by farmer themselves. 12. Sediment desposit in reservoir should be thoroughly dreged so as to secure a original design storage capacity. 13. The structure of overflow weir should be automatic so as to freely control flood level and not to increase dam height.