• Journal of Environmental Impact Assessment
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• v.26 no.3
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• pp.181-194
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• 2017

While over 90 percent of fishways are made up with concrete material, nature-like fishways are started to be established as a form of small stream using natural materials. Recently, the central government in collaboration with a university has proposed a 'Standard Model of Nature-like Fishway' with a purpose to provide as a national design standard of nature-like fishway. This study aims to criticize the proposed design model of nature-like fishway and to propose improvements by examining other international cases. As a result, we found problems and limitations of the proposed design model due to the lack of research and experience about making nature-like fishway in Korea. Especially, for designing bypass nature-like fishway we found the lack of studies about structure management strategies, establishment of rocks or pebbles inside the stream, and natural materials. In this sense, more studies about nature-like fishway design adaptable to our environment need to be conducted. In addition, since the proposed design standard for nature-like fishway has been created based on the limited examination of existing domestic cases, it is desirable to improve the design standard on the basis of hydrological and biological research so that they could be adapted effectively to regional and local contexts.

• Korean Journal of Ecology and Environment
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• v.48 no.4
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• pp.212-218
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• 2015

In South Korea, various nature-like fishways recently been installed for use by a wide variety of fish species. However, limited attempts have been made to monitor the fish utilization. The present study was conducted to ascertain the frequencies and patterns of utilization of the fishway installed at Beakjae Weir. We collected fish species that use the fishway by installing a fyke net at the exit of the fishway at least once a month from April 2013 to October 2013. Additionally, in order to identify all fish species that can potentially use the fishway, we investigated the fish fauna downstream to Beakjae Weir (mainstream of the Geum River). We found that 10 species belonging to 2 families used the fishway; this accounted for 64% of the total species inhabiting the mainstream. The species that used the fishway most frequently were Microphysogobio jeoni, followed by Squaliobarbus curriculus and Opsariichthys uncirostris amurensis. The highest number of fish using the fishway was observed in August, which was positively correlated with the water temperature (Spearman rank correlation, $r_s$=0.743, P=0.035). The sizes of the fish using the fishway varied widely, with the total body length ranging from 39 mm to 550 mm. Analysis of the time-dependent utilization frequency revealed that most fish used the fishway during the night (20:00~08:00). Compared to other fishways installed along the Geum River, the fishway installed at Beakjae Weir was used by fewer species and fish. This may be attributed to the structural inadequacy of the fishway, thereby resulting in a low attraction efficiency. Therefore, measures should be adopted to enhance the fishway attraction and passage efficiency. The results of this study can be used to ensure efficient operation and management of the Beakjae Weir fishway as well as serve as basic data for developing and building nature-like fishways tailored to Korean situations.

• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.5
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• pp.11-20
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• 2007

In this study, we reviewed the optimal space for the fishway and fish storage establishment in the section between the downstream of the Hwacheon dam and the confluence of the Pungsan river. The hydraulic stability of these facilities was also examined. In the section between the downstream of Hwacheon dam and the confluence of Pungsan river, the release flow of Hwacheon dam was set at $5,495m^3/s,\;6,110m^3/s$ and $7,537m^3/s$, and numerical simulations were executed for each instance using the HEC-RAS model and RMA-2. In the analysis of the flow velocity distributions in the subject section by release flows of Hwacheon dam, it was shown that there was over 5.0m/s of high flow velocity at Sta. $#1{\sim}Sta.$ #3, Sta. $#4{\sim}Sta.$ #6, and Sta. $#12{\sim}Sta.$ #13 of the sections analyzed in this study. The Sta. $#0{\sim}Sta.$ #1 was considered appropriate for the fishway and fish storage establishment. As seen in the results of the numerical stability review by release flow conditions of Hwacheon dam subject to the selected available areas fur fishway and fish storage, the topographically available section for the establishment of fishway and fish storage exists at Sta. $#1{\sim}Sta.$ #3 when the release flow of Hwacheon dam is $5,495m^3/s$, whereas Sta. $#0{\sim}Sta.$ #1 should be reviewed for the subject section for the establishment of fishway at release flows of $6,110m^3/s$ and $7,537m^3/s$, in addition to the figures gathered at the $5,495m^3/s$ release flow. Finally, the available section for the establishment of fishway and fish storage was determined to be Sta. $#0{\sim}Sta.$ #3. Further, if fishway and fish storage are established in the outer bank within this section, the high flow velocity section should be avoided. An alternative would be to establish for the fishway in the inner band on the section of Sta. #1 or Sta. #3.

• Journal of Korea Water Resources Association
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• v.34 no.4
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• pp.365-379
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• 2001

This paper presents an echo-hydraulic experimental approach to assessment of ascending capacity of migratory fish in a baffled fishway. Sweetfish, Plecoglossus altivelis, trout, Oncorhynchus mykiss, are used in these experiments. Ascending environment of the migratory fish in rivers is analyzed through the results of taco-hydraulic experiments. Important factors affecting the ascending capacity of migratory fish in baffled fishways are the discharge and slope of fishways and the fall height between the fishway entrance and the river bed. In these fishways the migratory capacity of sweetfish for a given fishway discharge is mainly affected by fishway slope, whereas the ascending capacity of trout for a given fishway slope was influenced by the change of fishway discharge. Loss of ascending properties of landlocked salmon, Oncorhynchus masou var ishikawai, was confirmed by these experiments. An ascending hydraulic criteria of the baffled fishway is defined by means of dimensionless factor F$_{f}$ and falling head H$_{f}$. Ascending capacity of migratory fish in existing baffled fishways in river of eastern coastal region is poor because the slope of fishways is verb steep.eep.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.14 no.3
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• pp.157-168
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• 2011

In order to promote efficiency of upstream and downstream migration of fishes, this study has developed a combined fishway of herring-bone bottom baffle type and brush type fishways. The results obtained are as follows : 1. In a channel with constant incline, the velocity of current generally shows a distinct tendency of acceleration as it goes down the stream. But in the hydraulic experiment of herring-bone bottom baffle type fishway, the velocity reached its maximum only at 0.4m/sec, and it tended to be stable without any acceleration. 2. The velocity in the brush type fishway showed a distinct tendency of acceleration as the discharge increased. But its greatest velocity was only 0.3m/sec, and its velocity change according to the discharge increase was only 0.15m/sec at maximum. 3. The maximum velocity in the combined type fishway was less than half of the blast speed of the poorest swimmer, the juvenile eel with 90mm of body length. So any species of fishes are supposed to be able to migrate upstream from the estuary through this combined type fishway. 4. The field experiment of upstream migration showed that the combined type fishway can promote efficiency of upstream and downstream migration of any species of fishes.

• Journal of Environmental Science International
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• v.21 no.11
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• pp.1395-1406
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• 2012

The purpose of this study is to analyze the hydraulic characteristics of the ice-harbor fishway by considering its geometrical form and utilize such analysis results as the foundational database to be used when establishing fishways in the future. first of all, the study realizes the same form as an ice-harbor fishway that is currently implemented via a FLOW-3D model and estimated the parameters that were optimal to the numerical mock test. Then, this study analyzed the level of sensitivity of the flow conditions which fluctuated due to the changes in geometrical changes by adjusting the inclination and pocket spacing by using the estimated optimal parameters. As a result, the study arrived at the following conclusions. The vortical velocity increased and had a significant effect on the inclination of the fishway. Furthermore, as the velocity within the vorticity increased due to the narrowed vortical area, it was determined that further studies on vorticities or the determination of the design method for the decrease in vortical velocity were imperative.

• Journal of Korean Society on Water Environment
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• v.31 no.1
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• pp.1-11
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• 2015

In this study, the attraction efficiency of the by-pass fishway installed at Dalseong Weir in Nakdong River was assessed according to operation of the attraction waterway by using River2D which is a two-dimensional physical habitat simulation model. The model was calibrated and validated through the measured water elevation. The attraction efficiency of the fishway was evaluated at the low flow condition because the target fish, Zacco platypus (Z. platypus), have moved frequently up and downstream at the spawning season from April to June. From simulation results, it can be deduced that the attraction efficiency at situation of open attraction waterway is superior to that of close attraction waterway. Also it is shown that velocity field at inner region of the fishway is suitable for migration of the fish.

• Water for future
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• v.27 no.2
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• pp.63-72
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• 1994

In this study, hydraulic characteristics for upstream migration of fish in a pool-and-weir fishway were analyzed through experiment. The results showed that streaming flow was preferable to plunging flow for upstream migration of fish and it was not good to make an orifice beneath the septum since it generates turbulent jet and eddies. Protrusions on the side wall of fishway were preferable to grooves since they decelerate flow velocity and make upstream migration easy. A vertically movable septum was necessary for a flushing of deposited bed material, and net installing over fishway was also needed for birds not to approach the fishway and eat fish.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.3
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• pp.1-7
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• 2010

The ichthyofauna and passing efficiency of fishways were surveyed in Geumgang estuary from May to October in 2009. The fishes collected were classified into 24 species, 23 genera belonging to 8 families. These 24 species consist of 17 freshwater fish species, 3 migration fish species and 4 peripheral freshwater fish species. Seasonal function of fishways showed the migration from May to June and returning to the reservoir of fishes be washed out to sea when sluice gate open by rainfall in July and August. Most of the fishes catched in fishways moved from middle tide to high tide except for July. Fishes ascended fishways between the middle ebb tide and the ebb tide only July, because small freshwater swim against the fishway for leaching the reservoir through the newly formed flow when the water level at the fishway kept dropping. Small fishes that body length less than 200 mm mainly used gabion type fishways and fishes over 200 mm utilized a cascade type fishways. Based on the total individuals collected, the efficiency of the fishway was 1 % for the anadromous fish and over 80 % for freshwater fish. Therefore, it is concluded that ecological function of the fishway in the Geumgang estuary dike be very important not only for fish migration but also freshwater fishes's returning.

• Korean Journal of Ecology and Environment
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• v.56 no.4
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• pp.348-362
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• 2023

This study analyzed the monitoring results of fishways at 16 weirs constructed on four large Rivers to provide data helpful for the operation and management of fishways. The average utilization rate of the fishways at the weirs was confirmed to be 64.9%. When comparing the dominant species in the mainstream and fishway monitoring results, differences were observed in 9 weirs (56.3%). This indicated that the species prevalent in the mainstream were not necessarily the ones most frequently using the fishways. The average number of individuals using the fishways per day was 336. When classifying the fish species using the fishway by life type, 92.3% were primary freshwater fish, and migratory species accounted for only 5.6%. Analysis based on the season of fishway usage revealed that an average or higher number of fish species used the fishways from May to October, with the highest number of individual users occurring from June to August. Between May and July, 80% of the fish species using the fishways were in their spawning period, while during other season, less than 40% were species that move during the spawning period. The fishways that showed a significant alignment between the spawning period and the fishway passage period were Rhinogobius brunneus, Leiocassis nitidus, Squalidus chankaensis tsuchigae, Pseudogobio esocinus, Acheilognathus rhombeus, and Pungtungia herzi, in that order. When comparing the fishway monitoring results of the Gangjeong-Goryeong Weir and the Dalseong Weir with the upper part water level of the weir, both the number of fish species and individuals using the fishway showed positive correlations with the upper part water level of the weir. This suggests that a higher water level of the weir increases the inflow discharge within the fishway, leading to increased use by fish (number of individuals in Gangjeong-Goryeong Weir, P<0.001; number of species in Dalseong Weir, P<0.05). This study summarized and analyzed the results of fishway monitoring at 16 weirs built on four large Rivers, considering fishway efficiency, operation and management, monitoring period, and regulation of water level in the upper part of the weir. It is thought that this will help understand the status of fish use in fishways on large River and aid the construction, operation, and management of fishways in the future.