• Title/Summary/Keyword: Surface water quality management

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Characterizing soils and the enduring nature of land uses around the Lake Chamo Basin in South-West Ethiopia

  • Zebire, Degife Asefa;Ayele, Tuma;Ayana, Mekonen
    • Journal of Ecology and Environment
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    • v.43 no.2
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    • pp.129-160
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    • 2019
  • Background: Characterizing and describing soils and land use and make a suggestion for sustainable utilization of land resources in the Ethiopian Rift valley flat plain areas of Lake Chamo Sub-Basin (CSB) are essential. Objectives: To (1) characterize soils of experimental area according to World Reference Base Legend and assess the nature and extent of salinity problems; (2) characterize land use systems and their role in soil properties; and (3) identify best land use practices used for both environmental management and improve agricultural productivity. Methods: Twelve randomly collected soil samples were prepared from the above land uses into 120 composites and analyzed. Results: Organic carbon (OC) and total nitrogen (TN) were varied along different land uses and depleted from the surface soils. The soil units include Chernozems (41.67%), Kastanozems (25%), Solonchaks (16.67%), and Cambisols (16.67%). The identified land uses are annual crops (AA), perennial crops (PA), and natural forest (NF). Generally, organic carbon, total nitrogen, percentage base saturation (PBS), exchangeable (potassium, calcium, and magnesium), available phosphorus (P2O5), manganese, copper, and iron contents were decreased in cultivated soils. Soil salinity problem was observed in annuals. Annuals have less nutrient content compared to perennials in irrigated agriculture while it is greater in annuals under rainfed. Clay, total nitrogen, available phosphorus, and available potassium (K2O) contents were correlated positively and highly significantly with organic carbon and electrical conductivity. Conclusion: Management practices that improve soil quality should be integrated with leguminous crops when the land is used for annual crops production.

Quality Characteristics of Sulgidduk by the Addition of Maesil(Prunus Mume) Cocentrate (매실농축액을 첨가한 설기떡의 품질특성)

  • Lim, Jeom-Hee;Jeong, Soon-Young;Kim, Jae-Hwan
    • Korean journal of food and cookery science
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    • v.26 no.6
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    • pp.761-771
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    • 2010
  • The purpose of this study was to determine the most desirable mixture ratio of Maesil (Prunus Mume) concentrate torice flour for the preparation of Sulgidduk. The five different levels of Maesil (Prunus Mume) concentrate were 0%, 4%,8%, 12%, and 16% and were stored over 3 days. The results of this study were as follows. First, the water activity of Sulgidduk was significantly increased upon addition of Maesil(Prunus Mume) concentrate to rice flour. However, in terms of mechanical texture characteristics, the hardness of Sulgidduk was decreased, Maesil(Prunus Mume) concentrate was added to Sulgidduk. The control was $764.58{\pm}5.3\;g/cm^2$. Each amounts of added Maesil(Prunus Mume) concentrate to rice flour (4%, 8%, 12%, and 16%) resulted in hardness levels of $633.44{\pm}13.0\;g/cm^2$, $617.64{\pm}16.2\;g/cm^2$, $585.31{\pm}27.5\;g/cm^2$, and $350.98{\pm}10.2\;g/cm^2$, respectively. In addition, both gumminess and cohesiveness of Sulgidduk increased with increasing amounts of added Maesil (Prunus Mume) concentrate to rice flour. Regarding the color value of Sulgidduk, with added Maesil(Prunus Mume) concentrate the L-value decreased, while both a-and b-value increased. In the sensory evaluation, surface color, taste, and flavor were improved with increasing amounts of Maesil(Prunus Mume) concentrate, whereas texture decreased. Based on sensory evaluation, Maesil (Prunus Mume) concentrate resulted in intensified color, taste, and flavor of Sulgidduk. Consequently, 4% to 8% Maesil (Prunus Mume) concentrate to rice flour was determined to the best formula for improving Sulgidduk in terms of sensory qualities such as moistness, color, taste, flavor and so on.

Effects of water physico-chemical parameters on tilapia (Oreochromis niloticus) growth in earthen ponds in Teso North Sub-County, Busia County

  • Makori, Agano J.;Abuom, Paul O.;Kapiyo, Raphael;Anyona, Douglas N.;Dida, Gabriel O.
    • Fisheries and Aquatic Sciences
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    • v.20 no.11
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    • pp.30.1-30.10
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    • 2017
  • Small-scale fish farmers in developing countries are faced with challenges owing to their limited information on aquaculture management. Nile tilapia farmers in Teso North Sub-County recorded lower yields than expected in 2009 despite having been provided with required inputs. Water quality was suspected to be the key factor responsible for the low yields. This study sought to assess the effects of earthen pond water physico-chemical parameters on the growth of Nile tilapia in six earthen fish ponds under semi-intensive culture system in Teso North Sub-County. The study was longitudinal in nature with pond water and fish being the units of analysis. Systematic sampling was used to select five ponds while a control pond was purposively selected based on its previously high harvest. Four ponds were fed by surface flow and two by underground water. Each pond was fertilized and stocked with 900 fry of averagely 1.4 g and 4.4 cm. Physico-chemical parameters were measured in-situ using a multi-parameter probe. Sixty fish samples were randomly obtained from each pond fortnightly for four months using a 10 mm mesh size and measured, weighed and returned into the pond. Mean range of physico-chemical parameters were: dissolved oxygen (DO) 4.86-10.53 mg/l, temperature $24-26^{\circ}C$, pH 6.1-8.3, conductivity $35-87{\mu}S/cm$ and ammonia 0.01-0.3 mg/l. Temperature (p = 0.012) and conductivity (p = 0.0001) levels varied significantly between ponds. Overall Specific Growth Rate ranged between 1.8% (0.1692 g/day) and 3.8% (1.9 g/day). Ammonia, DO and pH in the ponds were within the optimal levels for growth of tilapia, while temperature and conductivity were below optimal levels. As temperature and DO increased, growth rate of tilapia increased. However, increase in conductivity, pH and ammonia decreased fish growth rate. Temperature and DO ranging between 27 and $30^{\circ}C$ and 5-23 mg/l, respectively, and SGR of 3.8%/day and above are recommended for higher productivity.

Development and Cost-effective Evaluation of Grass Blocks Minimizing Construction Waste (건설폐기물을 최소화한 비용 효율적 잔디 블록 기법 개발 및 평가)

  • Jeon, Minsu;Hong, Jungsun;Jeon, Jechan;Kim, Lee-Hyung
    • Journal of Wetlands Research
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    • v.19 no.3
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    • pp.359-365
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    • 2017
  • Impermeable surfaces such as transportation land uses including roads and parking lots accumulate high heavy metals and particulate matters concentration especially during dry season which worsens the river water quality and distort the water circulation system during rainfall events. Recently, the government has been promoting policies to install Low Impact Development (LID) facilities such as permeable pavements or grass blocks in parking lots or pavements. However, transition of asphalt-paved surfaces to permeable pavement generated asphalt wastes which are detrimental to the environment and has cost implications due to its removal and disposal. Therefore this study was conducted to provide a method of constructing a cost-effective permeable pavement to reduce waste generation and cost. In this study, comparative analysis of the water circulation capacity and economic efficiency of the traditional construction method and new method proposed in this study through the lab-scale experiment. The proposed method was to make holes in existing asphalt pavements, layout geotextile fabric and permeable base media such as sand before compaction. After compaction, layout grass blocks on the compacted base media then layout sand in between each grass blocks before compaction. Apparently, there was no significant difference between the traditional installation method of permeable pavement and the proposed method in this study considering surface runoff, infiltrated volume, stored volume, and rainfall-runoff delay time. The proposed method in this study generated 86% less wastes compared to the traditional installation method and has 70% cost reduction considering asphalt removal and disposal. The construction method proposed in this study yielded similar performance compared to the traditional installation method and water circulation effect, but was proven to be less complicated and economical.

Community Dynamics of Phytoplankton and Bacteria as Affected by Physicochemical Environmental factors in Hoeya Dam Reservoir (회야댐 저수지에서 물리 ${\cdot}$ 화학적 환경요인에 따른 식물플랑크톤과 세균 군집의 변화)

  • Kim, Dae-Kyun;Choi, Ae-Ran;Lee, Hye-Kyeong;Kwon, O-Seob;Kim, Jong-Seol
    • Korean Journal of Ecology and Environment
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    • v.37 no.1 s.106
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    • pp.26-35
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    • 2004
  • We investigated the effect of physicochemical environmental factors on the community dynamics of phytoplanktons and bacteria at the Hoeya Dam Reservoir, a drinking water reservoir for Ulsan city. Water samples were collected and analyzed every two to four weeks at three sites along the reservoir from April to October, 2001. During the study period, the Secchi depths were between 0.4 and 3.5 m. At the surface layer of water column, temperature ranged 10.2 ~ $32.0^{\circ}C$, pH 7.3${\sim}$9.6, dissolved oxygen 5.5 ${\sim}$ 12.4 mg $L^{-1}$, $BOD_5$ 0.8 ${\sim}$ 5.0 mg $L^{-1}$, $COD_{Mn}$ 3.7 ${\sim}$ 10.0 mg $L^{-1}$, and Chl-a 8.9 ${\sim}$ 60.9 mg $m^{-3}$. At the bottom layer, temperature varied 7.2 ${\sim}$ $28.9^{\circ}C$, pH 7.1 ${\sim}$ 9.3, dissolved oxygen 0.6 ${\sim}$ 9.7 mg $L^{-1}$, $BOD_5$ 0.8 ${\sim}$ 4.5 mg $L^{-1}$, $COD_{Mn}$ 3.9 ${\sim}$ 10.0 mg $L^{-1}$, and Chl-a 4.3 ${\sim}$ 81.9 mg $m^{-3}$. The numbers of phytoplanktons were 7.4${\pm}10^2{\sim}2.6{\pm}10^5$ cells $mL^{-1}$ at surface and 2.5${\pm}10^2{\sim}2.4{\pm}10^4$ cells $mL^{-1}$ at bottom, and were positively correlated with water temperature and Chl- a concentration. Genus Stephanodiscus and genus Oscillatoria dominated on April and on May, respectively. Cyanobacterial blooms of Aphanizomenon, Microcystis, Anabaena were observed from June to early September, and thereafter Stephanodiscus and Aulacoseiral dominated again. Total microbial counts ranged 1.73${\pm}10^4{\sim}1.68{\pm}10^5$ cells $mL^{-1}$, and were positively correlated with water temperature and phytoplankton counts at surface water. Heterotrophic plate counts (HPCs) ranged 30${\sim}4.1{\pm}10^3$ CFU $mL^{-1}$, and were positively correlated with $BOD_5$ and $NO^3\;^-$-N concentration at bottom water. Unlike the total microbial counts, the numbers of fecal coliforms and fecal streptococci as well as HPCs were higher at the bottom than the surface layer and were highest at the upper a site among the three sampling sites. Since the concentrations of fecal coliforms and streptococci were still high at the bottom of site c, where intake for water treatment plant is located, it appeared that special management of water treatment processes may be needed especially after strong rainfall.

Removal and Release Velocities of Nutrients by Submerged Plants in Flood Control Reservoirs around Juam Lake (주암호 홍수조절용지내 침수 식물체의 영양염류 제거속도 및 용출속도)

  • Han, Jong-Hak;Seo, Dong-Cheol;Kim, Sang-Don;Kang, Se-Won;Lim, Byung-Jin;Park, Jong-Hwan;Kim, Kap-Soon;Lee, Jun-Bae;Kim, Hyun-Ook;Heo, Jong-Soo;Cho, Ju-Sik
    • Korean Journal of Environmental Agriculture
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    • v.30 no.2
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    • pp.144-152
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    • 2011
  • BACKGROUND: Eutrophication occurs occasionally in flood control reservoirs around Juam lake in summer and early autumn. Lakeside macrophyte which is one of internal pollutants effects on water quality when it is submerged during water surface is rising after rainy season. METHODS AND RESULTS: To improve water the quality of water from water supply source and to establish the management plan of submerged plants in flood control reservoirs around Juam Lake, the removal and release velocities of nutrients by submerged plants in site 1 and 2 were investigated. Removal or release velocity constant (K) of COD by Carex dimorpholepis Steud in column was 0.07~0.18 $day^{-1}$ at 0~4 days after flooding, -0.23~-0.17 $day^{-1}$ at 5~19 days after flooding and -0.28~0.03 $day^{-1}$ at 20~33 days after flooding. Removal or release velocity constant (K) of T-N by Carex dimorpholepis Steud was 0.02 $day^{-1}$ at 0~4(8) days after flooding, -0.13~-0.10 $day^{-1}$ at 5(9)~33 days after flooding in column. Removal or release velocity constant (K) of T-P by Carex dimorpholepis Steud was 0.05~0.06 $day^{-1}$ at 0~4 days after flooding, -0.14~-0.09 $day^{-1}$ at 5~33 days after flooding. Release velocity constant (K) of nutrients by Miscanthus sacchariflorus Benth was lower than that by Carex dimorpholepis Steud. In site 1, the amount of nutrients release by Carex dimorpholepis Steud was 6,719 kg/month/area for COD, 2,397 kg/month/area for T-N and 466 kg/month/area for T-P. The amounts of nutrients release by Carex dimorpholepis Steud were higher than those by Miscanthus sacchariflorus Benth in both sites. CONCLUSION(s): The results of this study suggest that COD, T-N and T-P in water quality of Juam lake were strongly influenced by submerged plants in flood control reservoirs.

A Function and Weight Selection of Ecosystem Service Function for the Eco-friendly Protected Horticulture Complex in Agricultural Landscape (시설원예단지의 친환경적 조성을 위한 생태계서비스 기능 및 가중치 산정)

  • SON, Jinkwan;KONG, Minjae;SHIN, Yukung;YUN, Sungwook;KANG, Donghyeon;Park, Minjung;LEE, Siyoung
    • Journal of Wetlands Research
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    • v.19 no.4
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    • pp.533-541
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    • 2017
  • Agricultural landscape has many ecosystem service functions. However, the development of the horticulture complex has no consideration for environmental conservation. Therefore, we analyzed the priorities of ecosystem service functions required for the composition. The study was conducted in three stages. As a result of the first survey, 17 functions were selected to be improved. In the second survey, 12 functions were selected excluding 5 functions. Finally, 1. Measures for water purification, 2. Groundwater recharge plan, 3. Surface water storage space, 4. Flood control measures, 5. Vegetation diversity space, 6. Carbon emission reduction plan, 7. Aquatic insect habitat space, 8. Amphibian reptiles 9. Landscape and Waste Management, 10. Bird Species Space, 11. Heat Island Mitigation Plan, 12. Experience / Ecological Education Plan. We proposed the structure, capacity, flow rate, arrangement and form of the water treatment facility to improve water quality by improving the function. We proposed a reservoir space of 7-10% for groundwater recharge. The development of reservoir and storage facilities suitable for the Korean situation is suggested for the surface water storage and flood control measures. And proposed to secure a green space for the climate cycle. Proposed habitat and nutrient discharge management for biodiversity. We propose green area development and wetland development to improve the landscape, and put into the facilities for experiential education. The results of the research can be utilized for the development and improvement of the horticultural complex.

First flush modeling of the radial type surface runoff and a placement strategy for stormwater inlets to improve the effectiveness of the first flush treatment in a small impervious catchment (방사형 강우 유출의 초기세척 모의 및 소규모 불투수 배수구역에서의 초기우수 처리효과 상승을 위한 집수시설 배치 방안)

  • Kang, Joo-Hyon;Lee, Dong Hoon;Kim, Jin Hwi
    • Journal of Wetlands Research
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    • v.19 no.4
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    • pp.375-382
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    • 2017
  • In this study, general characteristics of dynamic behavior of stormwater runoff from a small impervious catchment was investigated from a series of simulations for a radial type surface runoff. Based on the simulation results, a better placement strategy for stormwater inlets to improve performance of a structural best management practice (BMP) was suggested. The degree of pollutant first flush from an ideal radial type impervious catchment was simulated using a 1-D diffusion wave equation coupled with a pollutant transport equation. The results showed that the first flush of the chemical oxygen demand was the strongest when the catchment length ranged 30-50m at a bed slope of 0.02. This result suggested that a required degree of the first flush can be intentionally obtained by just changing the locations and numbers of stormwater inlets, and thereby adjusting the catchment length. Particularly, the overall performance of a structural BMP in reducing pollutant load can be improved by placing the stormwater inlets at locations for obtaining a required first flush strength.

Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013 (설비공학 분야의 최근 연구 동향 : 2013년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.12
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    • pp.605-619
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    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.

Development of High-frequency Data-based Inflow Water Temperature Prediction Model and Prediction of Changesin Stratification Strength of Daecheong Reservoir Due to Climate Change (고빈도 자료기반 유입 수온 예측모델 개발 및 기후변화에 따른 대청호 성층강도 변화 예측)

  • Han, Jongsu;Kim, Sungjin;Kim, Dongmin;Lee, Sawoo;Hwang, Sangchul;Kim, Jiwon;Chung, Sewoong
    • Journal of Environmental Impact Assessment
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    • v.30 no.5
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    • pp.271-296
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    • 2021
  • Since the thermal stratification in a reservoir inhibits the vertical mixing of the upper and lower layers and causes the formation of a hypoxia layer and the enhancement of nutrients release from the sediment, changes in the stratification structure of the reservoir according to future climate change are very important in terms of water quality and aquatic ecology management. This study was aimed to develop a data-driven inflow water temperature prediction model for Daecheong Reservoir (DR), and to predict future inflow water temperature and the stratification structure of DR considering future climate scenarios of Representative Concentration Pathways (RCP). The random forest (RF)regression model (NSE 0.97, RMSE 1.86℃, MAPE 9.45%) developed to predict the inflow temperature of DR adequately reproduced the statistics and variability of the observed water temperature. Future meteorological data for each RCP scenario predicted by the regional climate model (HadGEM3-RA) was input into RF model to predict the inflow water temperature, and a three-dimensional hydrodynamic model (AEM3D) was used to predict the change in the future (2018~2037, 2038~2057, 2058~2077, 2078~2097) stratification structure of DR due to climate change. As a result, the rates of increase in air temperature and inflow water temperature was 0.14~0.48℃/10year and 0.21~0.41℃/10year,respectively. As a result of seasonal analysis, in all scenarios except spring and winter in the RCP 2.6, the increase in inflow water temperature was statistically significant, and the increase rate was higher as the carbon reduction effort was weaker. The increase rate of the surface water temperature of the reservoir was in the range of 0.04~0.38℃/10year, and the stratification period was gradually increased in all scenarios. In particular, when the RCP 8.5 scenario is applied, the number of stratification days is expected to increase by about 24 days. These results were consistent with the results of previous studies that climate change strengthens the stratification intensity of lakes and reservoirs and prolonged the stratification period, and suggested that prolonged water temperature stratification could cause changes in the aquatic ecosystem, such as spatial expansion of the low-oxygen layer, an increase in sediment nutrient release, and changed in the dominant species of algae in the water body.