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In this experiment, we analyzed live fish (silver carp) trajectories recorded in an experimental vertical-slot fishway. Combined with a numerical simulation, we demonstrated that randomness shown in fish trajectories might not merely be attributed to the fish’s random choices in its swimming, but could also be a consequence of adaption to the bulk unsteady turbulent flow structures. Simple superposition of a fish trajectory on the time-averaged flow field obtained either by interpolating on discrete point measurements or numerical simulation data is not an ideal method for description of fish movement. How to model the fish paths in transient flow and the necessity of simultaneous recording of the flow field and the fish locomotion are challenging topics. We also discussed the possible integration of currently existing methods to promote the development of fish trajectory modeling. Role of Transient Characteristics in Fish Trajectory Modeling

International audience; The development of passage systems for migratory fish is crucial to mitigate the impact of river fragmentation. Concerning downstream migration of juvenile salmon (smolts), understanding their behaviour is a key to improving the efficiency of bypass systems. Among devices to improve efficiency, artificial lighting has proved effective in certain situations. Based on (1) recent observations of early migrating smolts where migration was delayed in the Poutès dam reservoir (Allier River, France) and (2) the fact that the implementation of bypass lighting devices was based on experiments involving later-season migrants, the present study assessed the effect of a lighting device on wild early-migrating smolts. One hundred wild smolts were tagged with acoustic transmitters and their behaviour near the bypass entrance under lit or dark conditions was assessed using 2D acoustic telemetry. A very abrupt change in behaviour around mid-April was observed, which directly affected their response to light. In the first phase of the downstream migration season (before mid-April), lighting significantly reduced the attractiveness of the bypass, while this surprisingly seemed to favour passage: smolts less frequently approached the bypass entry zone but passed through it more frequently. However, in the second phase (after mid-April), lighting attracted and kept the smolts close to the bypass entrance and significantly increased passage, corroborating previous experiments. The present study demonstrated an interaction between the development of migratory fish and their behaviour under lit or dark conditions. It also highlighted the importance of taking account of such behavioural change during the migration season when designing fish passage systems.

In contrast to the efforts made to develop functioning fishways for upstream migrants, the need for effective downstream migration facilities has long been underestimated. The challenge of developing well-performing bypasses for downstream migrants involves attracting the fish to the entrance and transporting them quickly and unharmed into the tailrace. In this study, the acceptance of different opening sizes of a surface bypass as well as the injuries which fish experience during the passage were examined. Overall bypass acceptance was low compared to the turbine passage. There was no significant difference in the number of downstream moving fish between the small and the large bypass openings. Across all fish species, no immediate mortality was detected. Severe injuries such as amputations or bruises were only rarely detected and at low intensity. Scale losses, tears and hemorrhages in the fins and dermal lesions at the body were the most common injuries, and significant species-specific differences were detected. To increase bypass efficiency, it would likely be useful to offer an alternative bottom bypass in addition to the existing surface bypass. The bypass injury potential could be further reduced by structural improvements at the bypass, such as covering protruding components.

Deep slot fishways (DSF) are similar to vertical slot fishways (VSF) except that a sill has been placed at the base of the slot, and thus require a lower discharge to operate. The conversion of a VSF to a DSF, which requires minimal design modifications, can make for a more flexible design in inflow management, maintaining the correct operation of the fishway in periods of limited water availability. It is, however, crucial to understand the new flow conditions that will be created inside the fishway, and their implications for fish passage. In this paper, the hydrodynamics of DSF were studied for two different pool configurations and five sill heights. The investigation comprised the analysis of the water surface configuration, the velocity and turbulence fields, as well as the definition of the equations that related discharges to depths in the pools. The DSF designs compared well in terms of water surface patterns and maximum velocities with VSFs, but resulted in a more complex three-dimensional flow pattern and increased turbulence levels. Further testing with fish is needed to analyze whether the benefits of retrofitting a VSF by adding a sill during low flows are cancelled out by increased fish passage difficulty.

River regulation has fragmented fluvial ecosystems in South America, affecting fish migration and dispersion dynamics. In response, authorities have installed fish passage facilities (FPF) to mitigate impacts. However, little is known about the geographical distribution of these facilities, and no synthesis of the research effort applied to understanding their functioning and limitations exists. To address this issue, our study gathered the available scientific literature about fishways in South America to provide an overview of studied FPF and associated research effort. We found 80 studies that investigated 25 FPF, mostly ladders installed in the upper reaches of large rivers, particularly in the Paraná River Basin. One important finding is that most facilities do not lead to upstream and/or downstream sites due to the presence of other dams with no FPF. Though the number of studies has increased over the past 10 years, there is no consistent trend towards increased research effort. Overall, studies have focused on the fishway itself (i.e. upstream passage), and rarely evaluated broader issues (i.e. habitat distribution, population dynamics, conservation and management success). Our research therefore identified technical limitations of past studies, and revealed important gaps in the knowledge of FPF as a management tool. RESUMO A implantação de barragens tem perturbado e fragmentado os ecossistemas fluviais da América do Sul, afetando a migração dos peixes e dinâmicas de dispersão. Sistemas de transposição de peixes (STPs) têm sido instalados na tentativa de atenuar esses impactos. No entanto, pouco se sabe sobre a distribuição geográfica desses dispositivos, bem como o esforço de pesquisa aplicado para entender seu funcionamento e limitações. Nosso trabalho reuniu a literatura disponível com a finalidade de fornecer um panorama sobre os mecanismos investigados na América do Sul, bem como revelar o esforço e perfil das pesquisas. Encontramos 80 estudos que investigaram 25 STPs, a maioria escadas instaladas nos trechos superiores de grandes rios, particularmente na bacia do rio Paraná. Um resultado interessante é que a maior parte dos STPs está desconectada de trechos a montante e jusante devido à presença de outras barragens sem STPs. Embora o número de estudos tenha aumentado na última década, não registramos tendência consistente de incremento ao longo dos anos. No geral, os estudos abordam aspectos do próprio STP, especificamente a passagem ascendente, ignorando temas mais abrangentes (i.e. distribuição de habitats, dinâmica populacional). Além disso, o foco da pesquisa se direciona especialmente às questões de eficiência da passagem e raramente ao contexto da conservação e sucesso do manejo. Nossa avaliação, portanto, indicou que os estudos pretéritos são tecnicamente limitados, revelando importantes lacunas sobre o conhecimento dos STPs como medida de manejo.

Le projet minier Nunavik Nickel a nécessité la construction d’un pont-seuil à l’exutoire du lac du Bombardier au Nunavik, Québec, Canada. Ce pont-seuil devait permettre aux poissons de transiter entre la rivière de Puvirnituq et le lac. Ainsi, une passe migratoire favorisant le passage de l’omble chevalier (Salvelinus alpinus) et du touladi (Salvelinus namaycush) a été aménagée à même le pont-seuil. À la suite de l’aménagement réalisé en 2012, une inspection de la passe migratoire et un suivi de son efficacité ont été réalisés à l’aide du système automatisé IchtyoSTM. L’inspection a révélé que les critères de conception étaient respectés bien que de légers travaux correctifs aient dû être réalisés au printemps 2013 pour améliorer l’appel de la passe migratoire. De juillet à septembre 2012, IchtyoSTM a enregistré 166 évènements correspondant à des passages de poissons, soit 114 touladis, 45 ombles chevaliers et 7 spécimens non identifiés. Un pic de montaison est survenu à la troisième semaine d’août. Ce pic est corrélé avec une augmentation des niveaux d’eau dans le lac à partir de la mi-août. Les montaisons ont été dominées par le touladi en juillet et août, pour passer à une dominance d’omble chevalier en septembre. Les informations récoltées confirment l’efficacité de la passe migratoire du pont-seuil à l’égard du libre passage de l’omble chevalier et du touladi en montaison., Development of the Nunavik Nickel mining project required the construction of a dam-bridge at the outlet of Lac du Bombardier (Nunavik, Québec, Canada). A fishway was incorporated into the dam-bridge complex to allow fish (primarily Arctic char (Salvelinus alpinus) and lake trout (Salvelinus namaycush) to move between the Puvirnituq River and the lake. Following completion of the fishway in 2012, it was inspected and its effectiveness assessed using the compute rized IchtyoSTM system. Inspection work confirmed that the fishway complied with the design criteria; however, some minor corrective work was conducted in spring 2013, to improve the attractiveness to fish of water flowing through the fishway. Between July and September 2012, the IchtyoSTM system recorded 166 fish passage events, which corresponded to 114 lake trout, 45 Arctic char and 7 unidentified fishes. A peak in upstream migration occurred during the third week of August, which was correlated with an increase in the lake water level that started in mid-August. The upstream migration was dominated by lake trout in July and August, and by Arctic char in September. The information recorded by the IchtyoS™ system confirmed the effectiveness of the fishway with regard to the free passage of upstream migrating Arctic char and lake trout.

I Sverige finns cirka 2000 vattenkraftverk men endast 10 procent har någon form av omlöp eller annan lösning (Risinger, 2012). Nya, strängare regler håller nu på att införas. Sedan 2014 finns en gemensam strategi från Energimyndigheten och Havs- och vattenmyndigheten för åtgärder i svensk vattenkraft (Risinger, 2014). En godkänd fiskväg är ett av kraven.Särskilt den småskaliga vattenkraften (energitillförsel under 10 MWh enligt Risinger (2012)) drabbas. Deras intäkter står många gånger i proportion till energiproduktionen och därmed saknas ofta de ekonomiska förutsättningarna för en fiskväg. Vidare kommer en del av vattnet, och därmed potentiella inkomster, att gå förlorade. Den här undersökningen syftar till att utröna vad ett omlöp får för konsekvenser i form av effektförluster. Det är naturligtvis omöjligt att komma fram till ett universellt svar. Istället mäts förlusterna hos ett specifikt mindre verk som redan har ett omlöp: Åby vattenkraftverk som ägs och drivs av Växjö kommun. Metoden som används är traversering i kombination med hydroskopisk flygel. Sedan tidigare finns beräknade värden från kommunen för flödet i omlöpet. Dessa jämförs med undersökningens uppmätta värden. Undersökningen visar att vid normalt vattenstånd (165,13 MÖH) flödar 167 ± 10 l/s vatten genom omlöpet. Detta är ett 70 l/s större flöde i jämförelse med kommunens beräknade värde. Förklaringar till den skillnaden ges av mätfel då djupet mättes och att inloppet hade byggts om mellan kommunens beräkningar och utförda mätningar. Även den formel som användes då de beräknade värdena togs fram föreslås som en tänkbar felkälla. 167 ± 10 l/s innebär ett bortfall om 4,2 ± 0,3 kW potentiell effekt. There are around 2000 hydropower plants in Sweden, but only 10 percent of them has a bio channel, fishway or equivalent solution (Risinger 2012). New, more strict rules are now about to be introduced. Since 2014 there is a mutual strategy from the two Swedish authorities ”Energimyndigheten” and ”Havs- och vattenmyndigheten”, which demands multiple actions from Swedish hydropower. (Risinger, 2014). An approved fishway is one of these.The small-scale hydropower plants (plants who produce less than 10 MWh according to Risinger (2012)) are especially affected from this. Their income is proportional to their production and therefore they’ll usually lack the economical ability to build a fishway. Furthermore, a part of the streaming water (which otherwise would equal income) will get lost. This study aims to decide the loss of effect a fishway causes. Of course, it is impossible to derive a universal answer. Instead the losses are measured at a specific smaller plant that already has a fishway: Åby hydropower plant that is owned and operated by Växjö municipality. Method being used is traversing in combination with a turbine flow meter. There are already calculated flows made by the municipality. These values will be compared with the measured values. The study shows that at a normal water level (165,13 m.a.sl) 167 ± 10 l/s of water is streaming through the fishway. This is a 70 l/s bigger flow in comparison with the municipality’s calculations. An explanation to this difference is given by measurement errors when the depth was measured, that the intake had been modified between when the calculations was being made and when the study’s measurements took place. Also, the formula being used for the calculated values is proposed as a possible source of error. 167 ± 10 l/s will result in a loss of 4,2 ± 0,3 kW potential effect.

Fishways are hydraulic structures that allow passage of fish across obstructions in rivers. Vertical slot fishways—VSFs—are considered the most efficient and least selective type of technical fishway solutions, especially due to their ability to remain effective even when significant upstream and/or downstream water level fluctuations occur. The scope of the present study is to perform numerical simulations in order to investigate and compare the hydraulic turbulent flow field in a standard and a simplified version of the most common VSF design. Implications in relation to fish swimming behaviour and fish passage performance are discussed. Different water depths (as well as discharges) were investigated, using a bed slope of 5%, as a reference for low-gradient VSFs with a very limited selectivity that can be used in multispecies rivers in grayling-barbel regions. Results show that maximum values of velocity, turbulent kinetic energy, and Reynolds stresses are higher in the standard design. However, corresponding to slot geometry and orientation, the direction of the main jet in the simplified design is more inclined towards the left side of the pool. This causes the eddy to split into 2 smaller ones; the minimum eddy dimension is reduced from 0.4–0.5 to 0.2–0.3 m. These dimensions are detrimental for fish passage efficiency, being more comparable with fish length (0.15–0.40 m), thus affecting migrating fish stability and orientation. Furthermore, the standard design provides a more straightforward upstream path and wider areas of low flow velocities and turbulence, useful for fish resting. Therefore, it is recommended that the standard design should be preferred over its simplified version, even if its construction costs are around 10–15% higher than the simplified one.

[EN] This End of Degree Project is a study on solutions of a fisway. The main purpose is to get back the longitudinal continuity of the river which has been pulled off by humanity along history. For that reason, a study has been carried out where in which all possibilities have been discussed, from knocking down the weir to doing a fish lift. Finally, A conclusión has been reached, due to the sizes of the weir, and its function of getting out the water for the irrigation ditch, the best solution is a vertical slot fishway. Vertical slot fishways do not have physical obstacles that could discriminate the icthyofauna, it works with a wide range of flow rates and it has side-baffles, which manage the major water flow. In order to be dimensionated it has been used an online application, property of CEDEX in colaboration with A Coruña University, called ¿Fish Path¿. With this tool, a 2.2 meters wide, 12.9 meters length and 9.5% slope fishway have been obtained. The pools have 1.75 meters length and the notches width is 0.35 meters. The current project concludes with a brief constructive study, which includes detailed work units and a Gantt chart, and finally the estimated budget., [CA] El present Treball de Fi de Grau es un estudi de solucions per a una escala de peixos. La finalitat de la mateixa és recuperar la continuitat longitudinal del riu que antropològicament li va ser llevada al llarg dels anys. Per tant, s'ha realitzat un estudi al cual s'han comentat totes les opcions existents, començant per la opció de demolir l'assut, fins la col·locació d'un ascensor per a peixos. Finalment s'ha arrivat a la conclussió de que per dimensions de l'assut i per la seua funcionalitat com derivació per a la séquia colindant, la sol·lució més adequada és una escala de clavill vertical. Les escales de clavill vertical no disposen d'obstacles físics que poden discriminar a la ictiofauna, funcionen amb un ampli rang de caudals i disposa de deflectors que dirigixen el flux principal d'aigua. Per al seu dimensionament s'ha empleat un programa d'internet, propietat del CEDEX amb la col·laboració de la universitat d'A Corunya, que es denomina "Fish Path". Amb aquesta ferramenta s'ha obtés una escala d'ample 2.2 metres, llarg 12.9 metres i una pendent del 9.5%. Les piscines tenen un llarg de 1.75 metres i els clavills tenen un ample de 0.35 metres. El present treball conclou amb un breu estudi constructiu, el qual inclou les unitats d'obra detalladles i un diagrama de Gantt, i finalment el pressupost estimat., [ES] El presente Trabajo de Final de Grado es un estudio de soluciones para una escala de peces. La finalidad de la misma es recuperar la continuidad longitudinal del río que antropológicamente se le ha arrebatado a lo largo de los años. Para ello, se ha realizado un estudio en el cual se han tratado todas las opciones existentes, desde la demolición del azud, hasta la colocación de un ascensor para peces. Finalmente se ha llegado a la conclusión de que por dimensiones del azud y por su funcionalidad como derivación para las acequias colindantes, la solución más adecuada es una escala de hendidura vertical. Las escalas de hendidura vertical no disponen de obstáculos físicos que puedan discriminar a la ictiofauna, funcionan con un amplio rango de caudales y dispone de deflectores que dirigen el flujo principal del agua. Para su dimensionamiento se ha empleado un programa online, propiedad del CEDEX en colaboración con la universidad de A Coruña, llamado "Fish Path". Con esta herramienta se ha obtenido una escala de ancho 2.2 metros, largo 12.9 metros y una pendiente de 9.5%. Las piscinas tienen un largo de 1.75 metros y las hendiduras de paso disponen de un ancho de 0.35 metros. El presente trabajo concluye con un breve estudio constructivo, el cual incluye las unidades de obra detalladas y un diagrama de Gantt, y finalmente el presupuesto estimado.

V diplomski nalogi je opisan primer matematičnega modeliranja turbulentnega toka v ribji stezi s programom PCFLOW2D. V zadnjem času se v Sloveniji posveča vedno večja pozornost raziskavam za izboljšanje vzdolžne povezljivosti vodotokov za doseganje dobrega ekološkega stanja, ki ga zahteva Vodna direktiva za vse stare in nove ribje steze do leta 2027. Pri tem lahko uporabimo tudi izračune s hidravličnimi modeli, ki pomagajo pri določevanju tokovne slike, s katero bomo ocenili primernost ribjih stez za ribje migracije. V prvem delu naloge se najprej predstavi glavne lastnosti najpogostejših tipov ribjih stez v svetu in našteje njihove dobre in slabe lastnosti, vključno z vprašanjem postavitve na pregradi. Razložen je pomen uspešnosti ribje steze in možnosti izboljšav našega razumevanja dogajanja na osnovi zbirke standardiziranih meritev migracij. V drugem delu naloge je obravnavana steza z vertikalno režo na HE Arto Blanca. Ker je tok izrazito dvodimenzionalen smo za simulacijo toka uporabili globinsko povprečni model PCFLOW2D z vgrajenim k-ε modelom turbulence. Izračun petih različnih primerov pretokov in štirih vzdolžnih padcev je pokazal, da je stopnja turbulence v stezi v največji meri odvisna od spremembe padca. Pri ugotavljanju primernost toka v stezi za ribe se izkaže, da imajo dovolj nizke vrednosti disipacije turbulentne kinetične energije le primeri z najmanjšim vzdolžnim padcem 10 cm na prekat ribje steze. This thesis discussses the use of mathematical modeling of a turbulent flow using PCFLOW2D in a fishway. Recently in Slovenia they gained increased attention for the research of the improval of the longitudinal connectivity of watercourses to achieve good ecological status required by Water Framework Directive for all existing and new fishways by the year of 2027. We can therefore use hydraulic models to calculate different flow conditions of various fishway examples to assess their suitability for fish migration. In the first part of the thesis we present the main features of the most common types of fishways currently used in the world and list their strengths and weaknesses. We then explain the importance of efficient fishways and how it could improve our understanding by collecting large data of standardized measurements of migrations on existing fishways. In the second part of the thesis we use the example of the vertical slot fishway used on HPP Arto Blanca. Its flow can be described as an example of a two dimensional flow. where the vertical component of the velocity is negligible, therefore we use depth-averged model of flow for the existing two planar velocity components. We perform our calculations with the k-ε turbulence model on four different examples of longitudinal slopes in five different flow conditions, which shows that the degree of turbulence is only slope dependent. When checking the suitability for target fish species it turns out that only the lowest level of longitudinal slope of 10 cm per pool gets sufficient enough low levels of dissipation of the turbulent kinetic energy.

International audience; n the scope to create efficient nature like fish ramps using large-scale roughness elements, the present study is an audit of modelling such complex 3D free surface flows using an industrial 2D code solving shallow water equations. Validation procedure is based upon the comparison between numerous experimental measurements and numerical runs around large-scale roughness patterns disposed on the flume bottom in order to determine what 2D reliable numerical results can be expected. In this paper, we focused on cases of unsubmerged obstacles. The results demonstrate that 2D shallow water modelling using an industrial code such as TELEMAC-2D can be a convenient way for the hydraulic engineer to help design a nature-like fishway. This article emphasizes the limitations due to 2D depth integration of velocities and turbulence modelling and gives the domain of validity of the method.

In Japan, many diadromous aquatics migrate for reproduction and/or growth between the seas and the rivers during their life history. They include many commercially important species for river fisheries, e.g. the ayu fish Plecoglossus altivelis, the Japanese eel Anguilla japonica, the Japanese mitten crab Eriocheir japonica, and so on. Many artificial structures like weirs and dams are constructed in the rivers of Japan and they become barrier walls that block migration. Most of the structures have fishways for big fish, e.g. salmon and trout, but those fishways are not always suitable for small diadromous animals. I have conducted a joint research with Yamaguchi Prefecture to improve the existing fishways with a low-cost and simple method of construction. The “Mizube-no-Kowaza” fishway is a slope type fishway having protruding boulders on its bed. The term of “Mizube-no-Kowaza” means a collection of small-scale devices for the improvement of river structures. We aim to connect the upper stream with the lower stream for aquatic organism’s migration by adopting the “Mizube-no-Kowaza” method. It can be constructed at low cost because of its simple structure. The “Mizube-no-Kowaza” fishway is effective in increasing wild resource of river dwellers by promoting networks among habitats isolated by manmade structures.

The construction of fish passages has been one of the strategies adopted by the Brazilian energy sector in order to diminish the effects of barriers on fish communities. However, studies of the efficiency of these mechanisms are scarce. The present study evaluated the efficiency and selectivity of the first trap and truck fish passage system in Brazil, installed in Santa Clara Dam, Mucuri River. The species composition in the Santa Clara Dam fish lift was compared to the original composition of Mucuri River fish fauna and with the populations that gather downstream of the dam during the reproductive season. The proportion of previously tagged individuals translocated by the lift was used to estimate its efficiency. During the 2003/2004 reproductive period, 67,841 individuals of 32 species passed through the lift, which corresponds to 66% of the lower Mucuri river fish richness. Less than 0.5% died or were injured during the passage. When compared to the river's population, less representative captures of smaller individuals and marine species were observed. However, the composition and structure of the community in the fish lift was quite similar to those downstream of the dam during the reproductive season. The estimated efficiency of the fish lift ranged from 0.2% for Pogonopoma wertheimeri to 16.1% for Leporinus conirostris reaching an average of 7% for all migratory species. A construção de passagens para peixes tem sido uma das estratégias adotadas pelo setor elétrico como forma de diminuir os efeitos de barramentos sobre as comunidades de peixes. No entanto, trabalhos de avaliação da eficiência destes mecanismos são escassos. Neste trabalho são avaliadas a eficiência e seletividade do primeiro elevador com caminhão tanque instalado no Brasil, na Usina Hidrelétrica de Santa Clara. A composição de espécies no elevador foi comparada com aquela original do rio, e com a das populações que se aglomeram a jusante da barragem, durante a estação reprodutiva. A proporção de indivíduos previamente marcados transpostos pelo elevador foi utilizada como forma de estimar sua eficiência. Durante o período reprodutivo (2003/2004) 67841 indivíduos de 32 espécies de peixes passaram pelo elevador, o que corresponde a 66% da riqueza do baixo curso do rio Mucuri. Destes, menos de 0,5% morreram ou foram feridos durante a passagem. Quando comparado com as populações do rio, foram observadas no elevador capturas menos representativas de indivíduos de pequeno porte e de espécies marinhas. No entanto, a composição e estrutura da comunidade no elevador foram bastante similares àquela observada a jusante da barragem durante o período reprodutivo. A eficiência estimada para o elevador variou de 0,2% para Pogonopoma wertheimeri até 16,1% para Leporinus conirostris, sendo de 7% para o conjunto de espécies migradoras.

A implantação de barramentos sejam eles para geração de energia, abastecimento de água, irrigação, dentre outros, tem promovido o impedimento da migração de peixes de piracema. No intuito de minimizar os efeitos negativos, causados por esses empreendimentos, surge em Minas Gerais a Lei 12.488, que obriga a construção de mecanismos para transposição de peixes (MTP) em barramentos, caso sejam necessários. Entretanto, a construção destes mecanismos em nosso país se baseia em modelos americanos, canadenses e europeus. No intuito de se conhecer o escoamento no mecanismo de transposição de peixes construído na UHE de Igarapava, realizaram-se testes em um modelo reduzido desse sistema na escala de 1:20. O mapeamento foi realizado com o auxilio de um Anemômetro LASER Doppler. Fez-se um conjunto de medidas em oito diferentes planos, e estes planos foram subdivididos em áreas de 10 x 10mm. Após o mapeamento foi possível “desenhar”, com auxílio do Matlab, os mapas representativos das iso-velocidades e vetores que ocorrem no MTP. Para isso utilizou-se de uma escala em cores nos contornos das iso-velocidades, onde as cores correspondem a magnitude das velocidades medidas, e o mapa de setas o direcionamento do escoamento, para verificação do comportamento do mesmo. Building a dam for hydropower, water supply, irrigation, and other purposes has an impact on fish migration. In order to solve this, the state of Minas Gerais introduced Law 12,488 law, which makes it mandatory to build a fishway in the dam when necessary. However the fishways built in Brazil, are similar to American, Canadian and European fishways. In order to know the flow in Igarapava Dam fishway, the system was tested on a 1:20 scale model. The test was performed using a LASER Doppler Anemometer on various planes. Then velocity color contours and arrow maps were drawn using MatLab, to find out the velocity field and flow behaviour in this fishway.

A crescente demanda de energia elétrica no Brasil tem alavancado a implantação de usinas hidrelétricas. Entretanto, a construção dessas estruturas promove impactos sobre o meio ambiente, especialmente no que diz respeito à migração de peixes. A partir do final dos anos 90 surgiram dispositivos legais que obrigam a construção de mecanismos para transposição de peixes (MTP), quando necessários. O desconhecimento sobre as características bio-hidráulicas dos peixes, a serem transpostos, tem obrigado os projetistas a utilizarem dados internacionais, de peixes do hemisfério Norte. Além disso, inexiste na literatura um estudo mais aprofundado sobre o campo de velocidades dentro dos MTP. Este trabalho apresenta um estudo sobre o escoamento em um MTP construído na UHE de Igarapava. O mapeamento de velocidades foi realizado utilizando-se um fluxímetro (molinete) com saída digital. Fez-se um conjunto de medidas em planos distantes entre si de 200mm. Estes planos foram subdivididos em áreas de 200 X 200mm. Após o mapeamento em campo foi possível “desenhar”, com auxílio do Matlab, os mapas representativos das velocidades que ocorrem no MTP. Para isso utilizou-se de uma escala em cores e setas, onde as cores correspondem a magnitude das velocidades medidas e as setas o direcionamento do escoamento, para verificação do comportamento do escoamento. The growing demand for electric power in Brazil has prompted the construction of new hydroelectric power plants. However, these new plants have had a strong impact on the environment, mainly on fish migration. Since the end of 1990s, strict new environmental laws have forced the design and installation of fishways in hydroelectric plants that have significantly affected the fish populations. Lack of information on the biohydraulic characteris- tics of several fish species which are in need of transposition systems for spawning and survival has forced the transposition system designers to use international technical data based on the characteristics of fish found in the Northern hemisphere. Moreover, the technical literature lacks studies on velocity fields in the fishway. This work deals with an experimental and analytical study about flow within a fishway built at the hydroelectric plant of Igarapava (UHE Igarapava). The flow velocity field is experimentally esti- mated by using a digital flowmeter. Velocity measurements are performed on planes 200m distant from each other. The area of each plane is about 200 mm x 200 mm. Afterwards, from the experimental velocity field data, the more representative flow velocity maps are graphically obtained by using Matlab software. The flow velocity maps are plotted using colors and arrows. The colors indicate the measured velocity magnitudes, while the arrows show the flow direction, providing a means to analyze flow behavior within the fishway.

V diplomskem delu so prikazani razlogi za gradnjo ribjih stez, vrste ribjih stez, ribja steza ob HE Arto Blanca, možnost njene optimizacije in analiza ihtiološkega pregleda s pomočjo hidravličnih vrednosti v ribji stezi. Ribje steze se gradijo za ohranjanje biološke povezanosti vodotoka pod in nad pregrado , ker je z gradnjo pregrade ta povezava prekinjena. To prizadene zlasti migratorne vrste rib in druge vrste organizmov, ki za svoje dolgoročno preživetje potrebujejo različne življenjske prostore. Predstavljen je problem ribje migracije na spodnji Savi v Sloveniji. Seznanimo se z ribami, ki tam živijo, in s plavalnimi sposobnostmi nekaterih najpogostejših rib v tem delu reke. V nadaljevanju so predstavljeni najpogosteje uporabljeni ribji prehodi. Določeni tipi ribjih prehodov so ustrezni le za določene vrste rib in vrste ovir. Leta 2009 je bila zgrajena ribja steza ob HE Arto Blanca, ki je ena redkih dobro delujočih ribjih stez na velikih pregradah v Sloveniji. Predstavljeni so njeni deli in način obratovanja njenega vtočnega odseka. Sledi prikaz optimizacije ribje steze s programom PCFLOW2D, ki ima možnost upoštevanja k-ε modela turbulence za nestalni tok. Kot osnovna geometrija je bila vzeta geometrija dela vtočnega odseka (ki je izveden kot bazenski tip z vertikalnimi režami) obstoječe ribje steze ob HE Arto Blanca. Ugotovljeno je bilo, da se s premikanjem reže med prekati proti sredini prekata zmanjšujejo maksimalne hitrosti in območja z izrazito veliko disipacijo turbulentne kinetične energije ε, zato pa se manjšajo območja z izrazito majhnimi hitrostmi in ε. Prav tako je bilo ugotovljeno, da v ribji stezi z vertikalnimi režami ni velikih sprememb parametrov ob spremembi pretoka, spreminja se le gladina vode. Na koncu so rezultati ihtiološkega pregleda ribje steze ob HE Arto Blanca ovrednoteni z rezultati optimiziranih hidravličnih vrednosti v ribji stezi. Ugotovljeno je dobro delovanje obstoječe ribje steze. This thesis deals with types of fishways and reasons for building them. It focuses on the fishway at HPP Arto Blanca, the possibilities for its optimization and the analysis of the ichthyological review based on the hydraulic data found in the fishway. Fishways are built in order to prevent interruptions of a watercourse which may occur when an obstacle is constructed. Especially migratory species of fish, but also some other organisms that depend on different habitats for their long-term survival, can be affected by such interruptions. The problem of fish migration in the lower section of the Sava River in Slovenia is presented. Species of fish living there and their swimming abilities are also described. This is followed by the description of the most frequently used types of fish passes. Certain types of fish passes are suitable only for certain types of fish and specific types of obstacles. The fishway at HPP Arto Blanca was built in 2009 and is one of the few well-functioning fishways on large dams in Slovenia. Its structure and the operation mode of its inlet section are discussed. The optimization of the fishway is then analyzed using the program PCFLOW2D and the k-ε turbulence model for unsteady flow. The geometry of a part of the inlet section of the existing fish pass at HPP Arto Blanca (implemented as a swimming pool type with vertical slots) served as a basic geometry. It was determined that, by moving the slots between the pools toward the center section, the maximum speed and areas with markedly high dissipation of turbulent kinetic energy ε are reduced. Consequently, areas with markedly low values of velocity and ε decrease. It was also found that a change in discharge causes no major parameter changes in the fishway with vertical slots. The only change observed is in the water level. Finally, an evaluation was performed, comparing the results of the ichthyological review of the fishway at HPP Arto Blanca with the results of the optimized hydraulic values in the fishway. The existing fishway was found to be well functioning.

V doktorski disertaciji so obravnavani različni pristopi k modeliranju toka v rekah s poplavnimi področji. Podatki, pridobljeni z meritvami na fizičnem hidravličnem modelu območja reke Save z izrazitimi poplavnimi področji, so služili za podrobno numerično analizo problematike izmenjave vode med tokom v glavni strugi in tokom na poplavnih področjih. Analizirani in dopolnjeni so bili modeli turbulence, vgrajeni v matematični model PCFLOW2D, ki ga že več kot dve desetletji razvijajo in dopolnjujejo na Katedri za mehaniko tekočin Fakultete za gradbeništvo in geodezijo Univerze v Ljubljani. Z analizo vpliva posameznega člena v dvodimenzijski dinamični časovno povprečeni Navier-Stokesovi (Reynoldsovi) enačbi, ki opisuje globinsko povprečen tok v rekah s poplavnimi področji, je bilo dokazano, da pri gibanju večjih vodnih mas po poplavnih področjih uporaba ustreznega modela turbelence ne igra bistvene vloge, saj je vpliv turbulence možno zadovoljivo zajeti preko trenjskega člena. Zato je bil v nadaljevanju obravnavan primer toka v ribji stezi, kjer je turbulenca zelo izrazita in ima njeno natančno modeliranje velik pomen. Na tem konkretnem primeru je bila opravljena občutljivostna analiza vgrajenega modela turbulence Smagorinsky. Analiza je pokazala, da je za dosego dobrega ujemanja numeričnih rezultatov z meritvami nujno umeriti koeficient Smagorinskega Cs, ki nastopa v modelu turbulence. To je novo dognanje, saj je v vseh nam znanih dosedanjih študijah ter drugih numeričnih programih priporočena vrednost koeficienta Cs enaka (oziroma spremenljiva znotraj zelo majhnega intervala) za vse vrste toka. Naša analiza je pokazala, da je vrednost koeficienta Cs zelo odvisna od uporabljene numerične mreže ter obravnavane vrste toka in lahko močno odstopa od do sedaj priporočenih vrednosti. Z detajlno občutljivostno analizo parametrov matematičnega modela je bil dosežen napredek pri razumevanju obravnavane problematike, kar v bodoče zagotavlja lažje in hitrejše umerjanje matematičnih modelov ter večje zaupanje v dobljene rezultate. This doctoral thesis discusses various approaches to modeling flow in rivers with floodplains. Measurements on a physical hydraulic model of the Sava River with distinctive floodplains provided noteworthy data which were used for a detailed numerical analysis of the flow interaction between the main channel and floodplains. Turbulence models incorporated into the mathematical model PCFLOW2D, which was developed more than two decades ago and is continuously being improved at the Chair of Fluid Mechanics with Laboratory, Faculty of Civil and Geodetic Engineering, University of Ljubljana, were precisely analyzed and modified. By analyzing the impact of a single term in a momentum two-dimensional time-averaged Navier-Stokes (Reynolds) equation, which describes the depth-averaged flow, it has been shown that in cases of flows in large water bodies, use of an appropriate turbulence model does not play an essential role because the influence of turbulence can be sufficiently covered through the friction term. Therefore the flow in a vertical slot fishway, where turbulence is very pronounced and its accurate modeling is of great importance was investigated. For this particular case, the sensitivity analysis was carried out for the recently integrated Smagorinsky turbulence model. Analysis has shown that, in order to achieve good agreement of numerical results with measurements, it is necessary to calibrate the Smagorinsky coefficient Cs. This is a new discovery, as to our knowledge all previous studies and other numerical programs recommended an equal value (or within a very small interval) of the coefficient Cs for all types of flow. Our analysis showed that the value of the coefficient Cs is highly dependent on the applied numerical grid and individual type of flow and can significantly deviate from the previous reference values. With the detailed sensitivity analysis of parameters of the mathematical model, progress has been made in understanding the issues addressed, which should in the future allow easier and faster calibration of mathematical models and greater confidence in the obtained results.

Durante a operação do elevador para peixes da Usina Hidrelétrica Santa Clara, de novembro de 2003 a março de 2004, todos os crustáceos palaemonídeos adultos que utilizaram o mecanismo foram contados e o número de jovens estimado. Duas espécies foram registradas: Macrobrachium carcinus (Linnaeus, 1758) e Macrobrachium acanthurus (Wiegmann, 1836). A utilização do mecanismo por adultos foi bastante restrita, com apenas 185 exemplares registrados. Porém, o número de jovens de M. carcinus utilizando o elevador foi estimado em 19.120 indivíduos. Embora o mecanismo avaliado tenha permitido a passagem dos palaemonídeos para montante do barramento, ficou clara a necessidade de novos arranjos estruturais e de manejo específicos para esses animais. Essas ações se referem ao desenvolvimento de estruturas direcionadas para a sua passagem e a adoção de vertimentos programados durante o período reprodutivo para permitir o carreamento de larvas para jusante. Esses dois caminhos representam formas efetivas de manejo, imprescindíveis para a manutenção das populações deste importante componente da biota aquática.During the Santa Clara Power Plant fish lift operation, from November 2003 to March 2004, Palaemonidae adult specimens were counted and identified and estimated juveniles number. Two Palaemonidae species were recorded: Macrobrachium carcinus (Linnaeus, 1758) and Macrobrachium acanthurus (Wiegmann, 1836). The use of the fish lift by adults was restricted, since only 185 individuals were registered. However, the estimated juveniles number was 19,120 individuals. Although existing fish passage systems could be considered as an alternative for Palaemonidae migration, planned spills during the reproductive periods could allow the drift of larvae. Moreover, the constructions of specific structures for upstream migration should be considered as an alternative for the maintenance of this important component of aquatic biota.

In the Netherlands the pool and orifice fishway is mainly intended for fresh water fish with a burst velocity u ≤ 1.00 m/s and which migrates in minor rivers and streams. Here we present the results of a scale model study, which focuses on the rating curve of the fishway and the flow velocity distribution in the orifices. The result of the investigation is a standard hydraulic design of the Dutch pool and orifice fishway for a design discharge 0.050 < Q < 0.150 m3/s.

Made available in DSpace on 2019-10-06T16:02:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-01 We evaluated the effectiveness of the fish ladder at Porto Primavera Dam in the severely regulated Upper Paraná River, for two Neotropical migratory fish species. Overall, 564 fish (448 Megaleporinus obtusidens and 116 M. piavussu) were PIT-tagged, released in upstream and downstream areas (on the left and right banks), and monitored continuously for 4 years. The fish performed two-way movements through the fish ladder, ascending from the tailrace and descending from the forebay. We registered entry into the fishway of 46 M. obtusidens (10.3%) individuals and only three M. piavussu (2.6%) individuals; therefore, all analyses were focussed on M. obstusidens. Entry proportion ranged from 0 to 48.1%, depending on the release site, and was greatest for fish released downstream near the fishway entrance. Entry times ranged from 3.0 to 384.0 days, and median times were 32.9 and 25.8 days for downstream and upstream respectively. Of fish that entered the fishway, passage percentages were 80% for fish released downstream and 100% for fish released upstream, and median transit times were 0.7 and 0.9 h respectively. Results suggest that if guidance and entry conditions can be improved, this fishway design holds promise as an effective solution for providing passage in both directions. Universidade Estadual Do Oeste Do Paraná Programa de Pos-Graduacao em Conservacao e Manejo de Recursos Naturais Jardim Universitário, Rua Universitária 2069 Universidade Estadual Do Oeste Do Paraná Grupo de Pesquisa em Tecnologia em Ecohidraulica e Conservacao de Recursos Pesqueiros e Hidricos Programa de Pós-Graduação em Recursos Pesqueiros e Engenharia de Pesca, Rua da Faculdade, 645 US Geological Survey-Leetown Science Center S.O. Conte Anadromous Fish Research Center Universidade Estadual Paulista-UNESP Engineering College of Ilha Solteira Department of Biology and Zootechny Fish Ecology Laboratory Universidade Estadual Paulista-UNESP Engineering College of Ilha Solteira Department of Biology and Zootechny Fish Ecology Laboratory

International audience; Diadromous species of tropical islands face numerous anthropogenic disturbances. Understanding how these disturbances affect the population dynamic of these species is important to develop ecologically based management measures. The upstream migration dynamics of two amphidromous gobies, Sicyopterus lagocephalus (Pallas) and Cotylopus acutipinnis (Guichenot), was described using intensive fishway monitoring (28 sampling dates over 1.5 years, 13 000 S. lagocephalus, 23 000 C. acutipinnis captured). Migration peak occurred for both species during the afternoon at the end of austral winter/beginning of austral summer. Abundance and size of fish caught in the river showed a marked impact of a dam (six sampling dates approximately 4000 individuals of each species captured). This study provides critical data for better management of fishways used by tropical amphidromous gobies. It appears especially important to reduce unwanted rheotactic sources that attract the fish away from the fishway's entrance.

La macrofaune des cours d'eau antillais est constituee principalement d'especes amphidromes de crevettes d'eau douce (Palaemonidae, Atyidae et Xiphocarididae) et de poissons (Gobiidae). Si la croissance et la reproduction de ces especes ont lieu en eau douce, le developpement larvaire necessite divers degres de salinite. La construction de prises d'eau (seuils et barrages collinaires) est susceptible de nuire a la fois aux migrations de devalaison et aux migrations d'avalaison. Les migrations de devalaison sont entreprises par les larves nouvellement nees qui sont emportees vers les estuaires par le courant. Les prises d'eau induisent donc des taux eleves de mortalite larvaire par entrainement des larves dans les conduites forcees. Les migrations d'avalaison sont principalement le fait de juveniles qui presentent un rheotactisme positif et un potentiel d'escalade des obstacles superieurs a ceux des adultes. Les ouvrages de faible hauteur realises au travers des cours d'eau representent des obstacles qui sont generalement franchis par escalade. Certains barrages collinaires realises aux Antilles ont ete equipes de dispositifs de franchissements. Aucun critere biologique n'a cependant ete pris en compte pour veritablement faciliter les migrations d'avalaison. En outre les migrations de devalaison par derive ont ete ignorees. Les exigences d'une libre circulation en relation avec le cycle de vie amphidrome des especes sont ici rappelees. Les taux eleves de mortalite larvaire peuvent etre reduits en evitant les prelevements d'eau durant les pics maximums de derive qui ont lieu durant les premieres heures apres la tombee de la nuit. En cas de prise d'eau en continu des dispositifs lumineux sont susceptibles d'orienter les larves vers les dispositifs delivrant les debits reserves ; ces dispositifs limiteraient ainsi l'entrainement des larves dans les conduites forcees. Limpermeabilite des barrages vis-a-vis des migrations d'avalaison peut disparaitre completement lorsque les ouvrages comportent des dispositifs sommaires de franchissements - de types « cascade » ou « passe en echarpe ».

Our understanding of biological design criteria to facilitate fishway passage design is limited, partially due to the lack of understanding of biological motivators, cues and constraints, as well as a lack of biological performance evaluations of structures once they are built. The Vianney-Legendre vertical slot fishway on the Richelieu River, Quebec, passes large numbers of migrating redhorse (Moxostoma spp.) upriver to spawning grounds each year. We evaluated the physiological capacity and relative swimming ability of three redhorse species (M. anisurum, M. carinatum, M. macrolepidotum, silver, river and shorthead redhorse respectively) to determine how these biotic factors relate to variation in fishway passage success and duration. Shorthead redhorse had higher maximum metabolic rates and were faster swimmers than silver and river redhorse. River redhorse recovered their lactate and glucose concentrations more quickly than silver and shorthead redhorse, and river redhorse were second in terms of metabolic recovery and swim speed. Additionally, fish sampled from the top of the fishway had nearly identical lactate, glucose and pH values compared to control fish. Using passive integrated transponders in 2010 and 2012 we observed that passage success and duration was highly variable among redhorse species and was not consistent among years suggesting that other factors such as water temperature, timing of the study and river flows modulate passage success. Clearly additional research is needed to understand how organismal performance, environmental conditions, and other factors (including abundance of conspecifics and other co-migrants) interact with fishway design features to dictate which fish will be successful and to inform design of future fishways. Our research suggests that there may be an opportunity for a rapid assessment approach where manual chasing and sampling of fish from the top of the fishway are used to determine which species (or sizes of fish) are exceeding their physiological capacity during passage. Fil: Hatry, Charles. Carleton University; Canadá Fil: Thiem, Jason D.. Carleton University; Canadá Fil: Binder, Thomas R.. Carleton University; Canadá Fil: Hatin, Daniel. Ministère des Ressources Naturelles et de la Faune; Canadá Fil: Dumont, Pierre. Ministère des Ressources Naturelles et de la Faune; Canadá Fil: Stamplecoskie, Keith M.. Carleton University; Canadá Fil: Molina, Juan Manuel. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnológico Bahia Blanca. Instituto de Ciencias Biologicas y Biomedicas del Sur; Argentina. Carleton University; Canadá Fil: Smokorowski, Karen E.. Fisheries and Oceans Canada. Great Lakes Laboratory for Fisheries and Aquatic Sciences; Canadá Fil: Cooke, Steven J.. Carleton University; Canadá

Dam building for hydropower production, dredging for log floating and drainage of peatlands have massively affected migrating salmonid populations in Finland. Increased sedimentation and changes in hydraulic conditions have destroyed the majority of spawning and rearing habitats in freshwater brooks and dam building has stopped migration upstream at river mouths. This thesis examines the current state of drained forest brooks, possibilities for restoration and methods to assist migration in rivers used for hydropower. Drainage down to the mineral soil has caused massive erosion and sedimentation in headwater brooks. The surface layer of a sand bed is constantly moving, preventing vegetation growth, while shortcuts created during drainage increase flow velocity and reduce retention time. The cross-sectional and longitudinal profiles become homogeneous and biodiversity is severely reduced. A simple wooden brook restoration structure was developed in laboratory experiments. Fish migration problems past a hydropower dam and reproduction possibilities offered by a natural-like bypass channel were studied in the river Oulujoki, the mouth of which was blocked by a hydropower dam in the late 1940s. Public pressure for remedial structures has grown since then and was given a boost after a fishway was opened at Merikoski, in the river mouth, in 2003. This thesis examined the next dam upstream, Montta at Muhos, which was studied separately as a partial and sole natural-like bypass. A natural-like bypass can offer stable conditions for spawning and rearing and can be designed precisely, through water flow and habitat modelling, to match desired conditions. The most important section in a fishway is ultimately the entrance. Fishway discharge is often merely a fraction of whole river discharge and the attractivity of the entrance can be increased by pumping additional discharge to the lowest part of the fishway. The hydraulics of a twin-slot vertical slot fishway were studied here by laboratory flume testing and 2D water flow modelling. Water flow and habitat modelling proved to be good tools in designing partly natural-like bypasses. However, fish behaviour should be closely monitored in any natural-like fishways already built, in order to verify the results of habitat modelling. Tiivistelmä Jokien patoaminen vesivoiman tuotantoon, ruoppaaminen puunuiton helpottamiseksi sekä latvapurojen ojitukset metsän kasvun edistämiseksi ovat voimakkaasti vaikuttaneet vaeltavien lohikalakantojen vaellus- ja lisääntymismahdollisuuksiin. Muuttuneet hydrauliset olosuhteet ja lisääntynyt sedimentaatio ovat tuhonneet lohikalojen lisääntymisalueet ja patoaminen on katkaissut ylösvaelluksen lisääntymispaikoille. Väitöstyö koostuu viidestä artikkelista, joissa esitellään uusia menetelmiä ja ratkaisuja lohikalojen vaelluksen ja lisääntymisen ennallistamiseksi. Kaksi artikkelia keskittyy ojituksesta kärsivien latvapurojen nykytilaan, kunnostusmahdollisuuksiin sekä kunnostusrakenteen kehittämiseen. Paikoin ojituksen seurauksena on ollut massiivinen mineraalimaan eroosio ja hienon hiekan sedimentoituminen puroihin. Puroihin on kertynyt paksuja hiekkakerroksia, joiden pintakerros on jatkuvassa liikkeessä. Pintakerroksen jatkuva liike estää kasvillisuuden kasvamisen. Osittain ojitus on myös oikaissut puroja, jolloin virtausnopeudet ovat kasvaneet ja veden viipymä lyhentynyt. Purojen pituus- ja poikkileikkauksen vaihtelu ja biodiversiteetti ovat on vähentyneet huomattavasti. Laboratoriokokeissa kehitettiin yksinkertainen puusta rakennettava kunnostusrakenne hiekoittuneiden purojen kunnostamiseksi. Kolme artikkelia käsittelee Oulujokea, kalateiden suunnittelua ja kalatierakenteita. Vuonna 2003 rakennettu Merikosken kalatie kasvatti paineita kalatierakentamiseen Oulujoen muille voimalaitoksille. Erityisesti väitöstyö keskittyi Montan voimalaitoksen ohitukseen suunniteltuun kalatiehen, jota tutkittiin virtausmallinnuksen avulla kokonaan ja osittain luonnonmukaisena ohitusuomana. Luonnonmukainen ohitusuoma voidaan suunnitella toimimaan kutukanavan tyyppisenä uomana, jonka tarkoitus on tarjota vakaat virtausolosuhteet lohikalojen lisääntymistä varten. Virtaus- ja habitaattimallinnuksen avulla uoma voidaan suunnitella tarkasti haluttujen virtausolosuhteiden mukaisesti. Kalatien toimivuuden kannalta tärkeintä on että kalat löytävät kalatien sisäänkäynnin. Kalatien virtaama on usein vain murto-osa koko joen virtaamasta, joten sisäänkäynnin houkuttavuutta voidaan lisätä lisävettä pumppaamalla. Kaksirakoisen pystyrakokalatien hydrauliikkaa tutkittiin sekä laboratorio- että virtausmallilla.

Fish passages are considered the oldest management tool used to minimize the impact of blocking fish migratory routes by hydroelectric power plants. However, fish passages are being installed without specific criteria in Brazil, with severe consequences to the conservation of the local fish fauna. Therefore, basic data gathered for fish passages already constructed could contribute to define operational rules, in addition to offer subsidies to decision-making and design of future facilities. Thus, the fish ladder of Baguari Dam was evaluated regarding temporal distribution, attraction, and ascension of the local fish fauna. A total of 20 fish samples were conducted immediately downstream of the dam and inside the fish ladder, from January 2010 to June 2011. Seasonal variation in fish abundance and richness was registered below the dam and inside the passage, with higher number of migratory fish in the reproductive season (Kruskall-Wallis, p = 0.04 and p = 0.05). Furthermore, higher concentration of migratory allochthonous and non-migratory species was registered for the spill bay (Wilcoxon, p = 0.009 and p = 0.006) compared to the tailrace, where the fish ladder entrance is located. This result suggests low efficiency of the attraction system of the mechanism during the reproductive period. Once entering the fish ladder, migratory species apparently ascend the facility due to the similar distribution throughout different stretches. Generally, the results showed that an operational rule for the Baguari Dam fish ladder should consider running the facility only during the reproductive period, unless the objectives of the passage are well defined. The attraction system must be more precisely evaluated, using technologies such as radiotelemetry. Similarly, fish ascension also should be better analyzed to evaluate the time spent to ascend and its influence in the reproductive biology of the species using the ladder. Pit-tag system could be used to approach this analysis. It is expected that the discussion of these results would be useful for companies of the energy sector and for environmental agencies in Brazil, subsidizing decisions related to the management of fish passages already installed and to the construction of new facilities in the country. As passagens ou sistemas de transposição de peixes são uma das ferramentas de manejo mais antigas utilizadas para minimizar o impacto do bloqueio de rota migratória de peixes pela implantação de barragens. Todavia, sua implantação tem sido realizada sem muito critério no Brasil, trazendo consequências muitas vezes graves à conservação da ictiofauna local. Por essa razão, dados básicos obtidos para as passagens de peixes em funcionamento podem contribuir para definição de sua regra operativa, além de subsidiar tomada de decisões e o design de futuros sistemas. Assim, a escada de peixes da UHE Baguari foi avaliada quanto à distribuição temporal, atração e subida da ictiofauna local. Foram realizadas 20 amostragens a jusante da barragem e no interior da escada de peixes entre janeiro de 2010 a junho de 2011. Observou-se variação sazonal na distribuição e riqueza de espécies de peixes a jusante da barragem e dentro da escada, sendo que as espécies migradoras foram registradas em maior abundância durante o período reprodutivo (Kruskall-Wallis, p = 0,04 e p = 0,05). Além disso, nesse mesmo período, maior concentração das espécies migradoras alóctones e não migradoras foi registrada para a bacia de dissipação da barragem (Wilcoxon, p = 0,009 e p = 0,006) quando comparado ao canal de fuga, local onde se encontra a entrada da escada. Isso sugere que a eficiência do sistema de atração do mecanismo não seja a esperada nesse período. Uma vez dentro da escada, aparentemente as espécies migradoras percorrem todo o mecanismo, distribuindo-se de forma similar ao longo de sua extensão. Em geral, os resultados obtidos demonstram que, aparentemente, a regra operativa da escada deva indicar seu funcionamento apenas no período reprodutivo, ao menos até que os objetivos da transposição de peixes na UHE Baguari sejam de fato definidos. Já o sistema de atração da escada deverá ser avaliado de forma mais precisa, utilizando-se tecnologias como radiotelemetria. Da mesma forma, a subida dos peixes pela escada deve ser melhor analisada para se avaliar o tempo gasto e a influência desse período sobre a biologia reprodutiva dos peixes. O sistema de Pit-tag pode ser utilizado para realizar essa análise. Espera-se que a discussão das informações obtidas no presente trabalho possa ser utilizada pelas empresas do setor elétrico e órgãos ambientais para subsidiar decisões relacionadas ao manejo de sistemas de transposição de peixes já em funcionamento e à construção de novos empreendimentos.

A construção de barramentos ao longo dos rios causa muitas alterações no meio envolvido. Entre esses impactos, tem-se a formação de uma barreira que impede o deslocamento do habitat aquático, interferindo, principalmente, na reprodução das espécies migratórias. Na tentativa de mitigar esse efeito, em muitas barragens, verifica-se a necessidade da implantação de mecanismos de transposição de peixes (MTP). Entre esses MTP têm-se as escadas para peixes que, quando empregadas e projetadas adequadamente, possibilitam a livre circulação das espécies. As escadas/passagens para peixes apresentam diferentes geometrias, de acordo com características natatórias dos peixes, altura do obstáculo e vazões disponíveis. Neste trabalho, avaliam-se as características do escoamento em uma escada do tipo ranhura vertical. Realizaram-se ensaios em um modelo com 0,60 m de largura, 0,60 m de profundidade, 9 m de comprimento e 6% de declividade, onde se representa, na escala 1:5, parte da escada para peixes instalada na UHE Igarapava (Minas Gerais). Foram realizadas medições da profundidade do escoamento, das pressões junto ao fundo e das velocidades do escoamento, em uma das bacias da estrutura, para três descargas. A região da ranhura na bacia onde ocorre a passagem da água entre bacias consecutivas foi estudada detalhadamente, já que representa uma região de passagem obrigatória e onde se esperam as maiores velocidades. Os resultados deste trabalho foram divididos em duas partes: (1) os parâmetros médios do escoamento e (2) características turbulentas do escoamento. Neste artigo, que representa a parte 1, são apresentados parâmetros adimensionais do escoamento e mostramse através de campos de isolinhas as características da profundidade do escoamento, das pressões e das velocidades médias do escoamento. Os resultados permitem caracterizar o comportamento médio do escoamento nessa estrutura e definir adimensionais importantes no dimensionamento dessas estruturas, entre eles, o coeficiente de descarga e a vazão adimensional. Quanto às velocidades do escoamento, verifica-se que estas não se alteram em função da descarga e da profundidade do escoamento, sendo a posição na bacia o principal fator que interfere. As velocidades máximas chegam, transpondo para o protótipo, a 2,0 m/s, sendo que predominam as componentes horizontais. As componentes verticais não ultrapassam 0,7 m/s (no protótipo) em regiões isoladas. Uma análise que confrontou os campos de velocidade na estrutura e as velocidades características de algumas espécies presentes na ictiofauna brasileira demonstrou que há regiões do escoamento que podem representar barreiras ao livre deslocamento dessas espécies. Dam construction along the rivers affects the biological communities by changing aquatic habitats, interfering in fish movements and causing serious restrictions to the reproduction of migratory species. In an attempt to reduce these effects, many dams include fishways to help species maintain their life cycles. Fishways can be of various types according to the obstacle height, fish species and available discharges. In this paper, flow patterns in a vertical slot fishway were studied. An experimental arrangement consisting of a 0.60 m wide, 0.60 m deep and 9 m long flume divided into nine pools was evaluated. This model represents a part of the fishway installed at the Igarapava Hydropower Plant in Minas Gerais (Brazil). Measurements were carried out on the flow depth, bottom pressure and flow velocity in one of the pools for three discharges. The slot region between consecutive pools was studied in detail since it represents an obligatory passage and it is where the highest velocities are expected. The results of this paper were divided in two parts: (1) the average flow parameters and (2) the characteristics of the turbulent flow. This paper (part (1) of the study) presents the non-dimensional flow parameters and isoline maps showing the characteristics of the flow depth, pressures and mean velocities. Through the analysis of results it was possible to characterize the average behavior of the flow. The results allowed defining important non-dimensional parameters of these structures, such as the discharge coefficient and the non-dimensional flow rate. Flow velocities do not change based on discharge and flow depth, the pool position is the main factor of interference. The maximum velocity of the flow can reach up to 2.0 m/s (prototype scale) and the horizontal components are predominant. The vertical components do not exceed 0.7 m/s (prototype scale) in isolated regions. An analysis that contrasted the velocity fields of the structure and the velocity characteristics of some species of Brazilian ichthyofauna demonstrated that there are regions of the flow with barriers preventing the free passage of these species.

Fish passage at artificial barriers is necessary for the conservation of healthy fish stocks. The first barrier that migratory fish encounter when ascending the Ebro River is the Xerta Weir, where a pool-type fishway was constructed in 2008. From 2007 to 2010, boat electrofishing surveys were conducted in the Ebro River downstream of the Xerta Weir to assess the potential pool of species that could use the fishway. Nine native and 12 exotic species were captured, the latter comprising 62 % of the relative abundance and 70 % of the biomass. A combination of video recording, electrofishing and trapping was used to assess the effectiveness of the fishway in facilitating the passage of fish. Eight species were detected using the fishway, of which five were native (Liza ramada, Anguilla anguilla, Barbus graellsii, Gobio lozanoi and Salaria fluviatilis) and three exotic (Alburnus alburnus, Cyprinus carpio and Rutilus rutilus). Only L. ramada used the fishway in substantial numbers. The rate of fish passage was the highest from June to August and decreased afterwards. The effectiveness of the fishway might be lowered by areas of turbulence within the fishway and by distraction flows from a nearby hydropower station. El paso de peces a través de barreras artificiales es necesario para la conservación en buen estado de las poblaciones de peces. La primera barrera que los peces migratorios encuentran ascendiendo el Río Ebro es el Azud de Xerta, donde en 2008 se construyó una escala de peces del tipo de estanques sucesivos. Para determinar el conjunto de especies que potencialmente podrían usar la escala se llevaron a cabo muestreos mediante pesca eléctrica desde embarcación aguas abajo del azud. Nueve especies nativas y 12 exóticas fueron capturadas, representando estas últimas el 62 % de la abundancia relativa y el 70 % de la biomasa. Se usó una combinación de grabaciones de video, pesca eléctrica y trampeo para evaluar la efectividad de la escala de peces. Ocho especies fueron detectadas en la escala, de las cuales cinco eran nativas (Liza ramada, Anguilla anguilla, Barbus graellsii, Gobio lozanoi y Salaria fluviatilis) y tres exóticas (Alburnus alburnus, Cyprinus carpio y Rutilus rutilus). Sólo L. ramada usó la escala en un número destacado. La tasa de paso de peces fue más alta de Junio a Agosto y descendió posteriormente. La efectividad de la escala puede estar limitada por areas de turbulencia dentro de la escala y caudales de distracción desde una central hidroeléctrica cercana.