• Title/Summary/Keyword: Weir Type

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Efficiency Analysis of the Ice Harbor Type Fishway Installed at the Gongju Weir on the Geum River using Traps (Trap을 이용한 공주보 아이스하버식 어도의 효과분석)

  • Lee, Jin-Woong;Yoon, Ju-Duk;Kim, Jeong-Hui;Park, Sang-Hyeon;Baek, Seung-Ho;Yoon, Jo-Hee;Jang, Min-Ho
    • Korean Journal of Environmental Biology
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    • v.33 no.1
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    • pp.75-82
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    • 2015
  • To overcome the stream fragmentation and blockage of migration of fishes by dams and weirs, fishways are commonly installed. However, limited studies were conducted for effectiveness and suitability of fishways installed in Korean streams. In this study, we investigated fish usages (by time periods, locations and months) of the Ice Harbor type fishway installed in the Gongju weir using traps. The monitoring were monthly conducted from June to October, 2012. The number of individuals which used fishway in September and October decreased than in June to August. Although no statistical significance was identified, many numbers of species and individuals were occurred at the trap installed at the left end of fishway than others. Fishes of more diverse size classes occurred at this trap as well. The number of collected individuals and water level of weir were positively correlated though they showed low correlation coefficient. Conversely, occurrence rate of fishes smaller than 70 mm of total length decreased with increasing water level of weir. fishway usage time of fish were different depends on ecological characteristics of each species. Various sizes of fishes can use fishway for their upstream migration. These results are useful for establishing management and evaluation plans of Ice Harbor type fishway in S. Korea.

Determination of management water level for the storage and flood controls in the underflow type of multi-stage movable weir using artificial neural network (인공신경망을 이용한 다단 배치된 하단배출형 가동보의 저류 및 홍수 조절을 위한 관리수위 결정)

  • Lee, Ji Haeng;Han, Il Yeong;Choi, Heung Sik
    • Journal of Korea Water Resources Association
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    • v.50 no.2
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    • pp.111-119
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    • 2017
  • The underflow type movable weirs were arranged in a multi-stage way along a reach at the Chiseong River, where flooding has been observed frequently. With management water level of the movable weirs the control effects of storage and flood were suggested and the control effects were compared with those of existed weir system. The water level for the targeted storage and flood elevation was suggested by building the artificial neural network model. When the underflow type of movable weirs were arranged in a multi-stage way, the peak flood elevation decreased by 68.28% in the downstream compared with the existed weir system, and the total storage of the target section of multi-stage movable weirs increased by 216%. As a result of numerical simulation to build the artificial neural network model, 60%, 20%, and 20% among 216 data were used for the training, validation, and test, respectively. The training result of mean square error was $0.1681m^2$ and the high coefficients of determination were 0.9961, 0.9967, and 0.9943 in the training, validation, and test, respectively. As a result the water level management of each movable weir for the controls of flood elevation in the targeted downstream and targeted storage was suggested by using the artificial neural network.

The Evaluations of Fish Survival Rate and Fish Movements using the Tagging Monitoring Approach of Passive Integrated Transponders (PIT) (수동형 전자발신장치(Passive Integrated Transponder, PIT) 모니터링 기법 적용에 따른 어종별 생존율 평가 및 어도에서 어류이동성 평가)

  • Choi, Ji-Woong;An, Kwang-Guk
    • Journal of Environmental Science International
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    • v.23 no.8
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    • pp.1495-1505
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    • 2014
  • The objective of this study was to evaluate survival rate and fish movement (migration) using a tagging approach of passive integrated transponder (PIT) in Juksan Weir, which was constructed as a four major river restoration projects. For this study, survival rates of each fish species and the mobility of fish individuals were analyzed during 2 weeks by the insertion of PIT tags to various fish species in the laboratory. According to tagging tests in the laboratory, the survival rate 37.5% (30 survivals of 80 individuals) after the insertion of PIT tags. The survival rate of Carassius auratus and Hemibarbus labeo was 100% and 80% after the insertion of the tags, respectively, whereas it was only 13.3% for Zacco platypus. In the field experiments of Juksan Weir, 6 species and 157 individuals from 8 species (563 individuals) were detected in the fixed automatic data-logging system, indicating a detection rate of 27.9% in the fishway of Juksan Weir. In the meantime, some species with no or low detection rates in the fixed automatic data-logging system were turn out to be stagnant-type species, which prefer stagnant or standing water to live.

Experimental study on the discharge coefficient of slope-type and step-type weirs (경사형 및 계단형 보의 유량계수 산정을 위한 실험연구)

  • Kang, Joon Gua;Kim, Jong Tae
    • Journal of Korea Water Resources Association
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    • v.49 no.12
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    • pp.961-969
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    • 2016
  • Due to the recent requirement of installing low-head structures considering environmental aspects, various types of fixed weir have been suggested. However, the design guideline of transverse structures for practical application is very limited. The purpose of the present study is to analyze the hydraulic properties of the fixed weirs installed at the small and middle sized rivers of Korea depending on the physical specifications to provide fundamental data that may be reflected to the design of a low-head fixed weir considering the relevant environmental aspects. The basic discharge coefficient of slope-type and step-type weirs depending on change of crest was estimated, and a stage-discharge curve was developed. In addition, the flow properties under free flow and submerged flow conditions were analyzed by varying the hydraulic conditions such as discharge and crest.

Changes in Landscape Characteristics of Stream Habitats with the Construction and Operation of River-Crossing Structures in the Geum-gang River, South Korea (금강에서 횡단구조물의 설치와 운영에 따른 하천 서식처의 경관 특성 변화)

  • Kim, Dana;Lee, Cheolho;Kim, Hwirae;Ock, Giyoung;Cho, Kang-Hyun
    • Ecology and Resilient Infrastructure
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    • v.8 no.1
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    • pp.64-78
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    • 2021
  • This study was conducted to find out the effect of the construction and operation of river-crossing structures on the habitat landscape characteristics in the Geum-gang River, South Korea. A total of three study reaches were selected in the downstream of the Daecheong Dam: the Buyong-ri reach, which is a control that is not affected by the construction and operation of the weir of the Four Rivers Project and Sejong-bo Weir reach and Gongju-bo Weir reach of the upper and lower sections of each weir that are affected by the weir construction and operation. The habitat type was classified, and then the structural characteristics of the landscape were analyzed using aerial photographs taken before and after the construction of the Daecheong Dam, before and after the construction of the weir, and before and after the weir gate operation. After the construction of Daecheong Dam in Geum River, the area of the bare land greatly decreased, and the area of grassland and woodland increased in the downstream of the dam. In addition, the patch number in the river landscape increased, the patch size decreased, and the landscape shape index and the habitat diversity increased. Therefore, after the construction of the dam, the bare land habitat was changed to a vegetated habitat, and the habitat was fragmented and diversified in the downstream of the dam. After the construction of the weirs, the area of open water increased by 18% in the Sejong-bo reach and by 90% in the Gongju-bo reach, and the landscape shape index of the open water decreased by 32% in the Sejong-bo reach and by 35% in the Gongju-bo reach, and the habitat diversity index decreased to 25% in the Sejong-bo reach and to 24% in the Gongju-bo reach. Therefore, the open water habitat was expanded, the shape of the habitat was simplified, and the habitat diversity decreased according to the construction of the weirs. After water-gate opening of the weir, the bare land that disappeared after the construction of the weir reappeared, and the landscape shape index and habitat diversity index increased in both terrestrial and open water habitats. Therefore, it was found that the landscape characteristics of the river habitats were restored to the pre-construction of the weir by the operation of the weir gate. The effect of weir gate opening was delayed in the downstream than in the upstream of the weir. Although the characteristics of the landscape structure in the river habitat changed due to the construction of the river-crossing structures, it is thought that proper technology development for the ecological operation of the structures is necessary as the habitat environments can be restored by the operation of these structures.

A Study on Reconstruction Models of Side-channel Spillway for Discharge Capacity Improvement (측수로형 여수로의 홍수배제능력증대를 위한 월류부 개축방안에 관한 연구)

  • Park, Sae-Hoon;Moon, Young-Il
    • Journal of the Korean Society of Hazard Mitigation
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    • v.7 no.3
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    • pp.9-18
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    • 2007
  • The small and medium sized dams have the fill dam type of a lot of occasions, which are often weak in cases of major floods. For this reason, although a countermeasure is in great need, due to the importance of the facilities and financial situations, no direct safety measures have been taken. In this study, in order to minimize construction expenditure for practical safety measures in cases of major floods, the overflow section of spillway has been analyzed focusing on how the overflow capacity will increase in the case of partially rebuilding a part of the overflow section of spillway favorable for hydraulic conditions. The labyrinth weir and movable weir was chosen for reconstruction models of the overflow section. Moreover, for analyzing the after-effects of the reconstruction, a small scale dam was temporarily chosen for various experiments such as the hydraulic model testing and the three dimension numerical evaluation through the use of Flow-3D.

Numerical simulations of turbulent flow on the pool and weir type fishway and analysis of ascending possibility of fishes (계단식 어도의 난류흐름 수치해석 및 어류 소상 가능성 분석)

  • Kwon, Yong-Joon;Ryu, Yonguk;Kim, Hyung Suk
    • Journal of Korea Water Resources Association
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    • v.56 no.spc1
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    • pp.1037-1048
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    • 2023
  • Fishways are constructed to ensure the fish migration because river-crossing structures such as dams and weirs cut off the stream longitudinal connectivity and influence on aquatic ecosystems. However, the passage efficiency of fishes varies depending on flow characteristics in the fishway and fish species. In this study, three-dimensional numerical simulations are carried out using a RANS model and the volume of fluid method for resolving free surface fluctuations to calculate the turbulent flow in the pool and weir type fishway. The Flow velocity and turbulent kinetic energy in the pool of fishway are analyzed according to variation of the upstream water level and the length of pool. The present numerical simulations reasonably well reproduce the stream flow and plunging flow characteristics in the pool. The simulation results show that the stream flow changes to the plunging flow as the length of the pool increases. When the upstream level increases, the stream flow becomes more evident. Key parameters related to the fish migration within the fishway such as the flow velocity and the turbulent kinetic energy are examined to assess the ascending possibility of fishes.

MIXED TYPE DUALITY FOR CONTROL PROBLEMS WITH GENERALIZED INVEXITY

  • Husain, I.;Ahmed, A.;Ahmad, B.
    • Journal of applied mathematics & informatics
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    • v.26 no.5_6
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    • pp.819-837
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    • 2008
  • A mixed type dual to the control problem in order to unify Wolfe and Mond-Weir type dual control problem is presented in various duality results are validated and the generalized invexity assumptions. It is pointed out that our results can be extended to the control problems with free boundary conditions. The duality results for nonlinear programming problems already existing in the literature are deduced as special cases of our results.

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ON DUALITY THEOREMS FOR CONVEXIFIABLE OPTIMIZATION PROBLEMS

  • Kim, Moon-Hee
    • Journal of applied mathematics & informatics
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    • v.26 no.5_6
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    • pp.1257-1261
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    • 2008
  • In this paper, we consider of a convexifiable programming problem with bounds on variables. We obtain Mond-Weir type duality theorems for the convexifiable programming problems. Moreover, we give a numerical example to illustrate our duality.

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DUALITY FOR MULTIOBJECTIVE FRACTIONAL CONTROL PROBLEMS WITH GENERALIZED INVEXITY

  • Nahak, C.;Nanda, S.
    • Journal of applied mathematics & informatics
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    • v.5 no.2
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    • pp.475-488
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    • 1998
  • Wolfe and Mond-Weir type duals for multiobjective con-trol problems are formulated. Under pseudo-invexity/quasi-invexity assumptions of the functions involved, weak and strong duality the-orems are proved to relate efficient solutions of the primal and dual problems.