International Conference on Engineering and Ecohydrology for Fish Passage

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Now showing 1 - 5 of 1214
  • Publication
    Cost Effective Modelling to Improve the Functionality of the Broken Creek Rice’s Weir and Kennedy’s Weir Vertical Slot Fishways
    (2018-12-13) Slarke, Steven; Muller, Jarrah; Stuart, Ivor; O'Connor, Justin; Jones, Matthew; Turner, Mark
    Acknowledgement Goulburn-Murray Water Broken Creek in north-central Victoria flows into the River Murray upstream of Barmah. There are 10 low-head (<2 m high) weirs on Broken Creek which all have vertical slot fishways however these have high turbulence (i.e. 75 W/m3) and thus limited functionality for several species of native small and medium sized fish (i.e. <300 mm long). In late 2017, the Victorian government (DELWP) engaged Jacobs and Kingfisher Research to hydraulically model the Rices and Kennedy’s Weir fishways to prepare conceptual designs for retro-fitted ‘key-hole’ slots to reduce pool turbulence and demonstrate potential for improvement in functionality to pass much smaller fish (i.e. >50 mm long). Jacobs applied a Microsoft Excel based fishway model which takes fishway geometry, calibrated slot discharge coefficient data, and headwater/tailwater ranges, and uses these data to predict individual pool turbulence, depth and slot velocity. These hydraulic outputs were combined with fish swimming ability, maximum allowable turbulence, and minimum water depth to graphically demonstrate water level ranges for which each fishway could pass small, medium and large-sized native fish. Conceptual level ‘key-hole’ slot designs were then developed, reducing slot areas and flow rates and enabling passage of all fish sizes. The modelling showed that The theoretical implementation of ‘key-hole’ slots effectively halved the fishway discharge and reduced the pool turbulence to 35 W/m3, the known threshold suitable for passage of small-sized native fish. This project demonstrated the efficiency of Microsoft Excel based modelling to bring together both fishway hydraulics and fish biology, with novel design options rapidly evaluated for a low cost. Graphical fishway operation tables were automatically produced for the full range of site operational conditions without the need for costly post-processing of model results. GBCMA propose to retrofit key-hole slots to Rice’s and Kennedy’s weir fishways to improve their performance during 2018.
  • Publication
    Fish ladders at small hydropower plants and potential contribution to downstream passage of eggs and larvae
    (2018-12-13) Brambilla, Eduardo
    Fish passage can potentially enhance downstream fish passage of larvae and eggs at small hydropower plants (SHP’s). To evaluate this hypothesis, two SHP’s located in the Sapucaí-Mirim River, Southeastern Brazil, both with weir-and-orifice type fish ladders were studied. Eggs and larvae were collected fortnightly between November 2016 and February 2017 (seasonal reproductive period) from set locations upstream of the dams, including the lotic, transition and reservoir. Additional downstream drifting samples were collected from within the fish ladders. Higher densities of eggs and larvae were collected, from all sampling sites, in December, January and early February. Larvae and eggs were only collected from the fish ladders during these periods and only during intense pluviosity events after river flow peaks. The low egg and larval abundance registered with the fish ladders, when compared with lotic, transition and reservoir sites, indicates that few eggs and larvae successfully move downstream through the fishway. They likely travel through turbines and/or the spillway, get eaten by predators or even simply drop out of drift. Increases in river flow has significantly influenced the passage through the fish ladders.
  • Publication
    Hydraulic Approach for Dimensioning Fish Way Attraction Flow
    (2018-12-13) Henning, Martin; Heneka, Patrick; Schuetz, Cornelia
    The German Federal Institute of Hydrology (BfG) and the German Federal Waterways Engineering and Research Institute (BAW) are working to restore upstream connectivity for fish on German Federal Waterways by means of fish ways. In order for fish to find the entrance of a fish way, sufficient attraction flow is necessary. However, to this day, there is no generally accepted definition of sufficient attraction flow and how to evaluate it. Furthermore, according to the European Water Framework Directive fish of all species and sizes have to be considered for upstream migration. Thus, requirements for attraction flow are diverse. Theoretically, attraction flow should be designed as large as possible. Practically, space for fish ways is often limited and large supply structures may lead to other restrictions, especially distract fish from their passage. In addition, in terms of operational discharge, fish ways often compete with hydropower and other interests. Thus attraction flow should be designed as large as necessary and as small as possible. It is common to design attraction flow rate as a proportion of competing flow, e.g. mean annual discharge or hydro power plant design discharge. However, these approaches do not consider site specific parameters such as geometric and hydraulic boundary conditions. The framework presented characterizes requirements for attraction flow by a simple set of variables. Hydraulic jet theory is used in order to estimate attraction flow diffusion and to take into account tailrace characteristics. In doing so, site specifics such as water depths, river bed boundaries and influence of competing flow are considered. The straight forward approach aims at applicable dimensioning recommendations for attraction flow rates and fish way entrance design.
  • Publication
    Optimisation of Fishway Entrance and Exit Conditions Using Physical Modelling: SARFIIP Pike Floodplain Regulator and Fishway Designs
    (2018-12-13) Slarke, Steven; Stuart, Ivor; Pezanitti, David
    As part of SARFIIP, Jacobs and Kingfisher Research prepared designs for two integrated regulator and fishway structures at the Pike floodplain for SA Water, DEW and the MDBA. These structures will enable the future managed inundation watering of Pike during regulated river flows to restore floodplain health and fish passage connectivity through the floodplain. A successful floodplain flow regulator and fishway design requires that fish are able to readily locate and enter the downstream entrance. The entrance must be located at the ‘limit of fish migration’, represented by either a wall or a line of turbulence below the regulator gate that fish cannot pass. The upstream fishway exit must be located where fish are not drawn back downstream over the gates. To confirm the optimal fishway entrance and exit arrangements, a 1:15 scale physical model was constructed and tested at the UniSA AFMG facilities. The model was designed to enable the performance of critical elements to be identified and if necessary, quickly adjusted. The sheet-metal model incorporated six lay-flat regulator gates and an adjustable downstream fishway entrance. The model was tested for variable scaled passing flows up to 3,000 ML/d. The modelling revealed the existence of complex hydraulics and the need to maintain the integrity of attraction flows to the fishway entrance. A ‘flow straightening wall’ was incorporated to ensure positive velocity vectors downstream of the entrance. A nib wall was provided across the regulator below the overshot gates to form the ‘limit of fish migration’, aligning with the fishway entrance. The location of the fishway upstream exit was also confirmed and the optimised arrangements demonstrated to the client. In summary, low-cost physical modelling was undertaken to optimise the fishway designs and provide certainty to the biological functionality of the structures and this helped maximise ecological value for investment.
  • Publication
    Fish Passage Remediation through the NSW Recreational Fishing Trust Habitat Action Grants
    (2018-12-13) Nichols, Scott
    The NSW Recreational Fishing Licence was introduced on 23rd March 2001. The funds generated by the licence are held in a Trust and used to improve recreational fishing in the state via a number of targeted programs including fish habitat restoration. One of the success stories of the NSW Recreational Fishing Trust has been the Habitat Action Grant (HAG) Program that directs funds to onground works via a devolved grant process. Since the HAG Program began in 2003, over $850,000 has been used to leverage 40 road crossing and weir fish passage remediation projects valued at $7.1M. Importantly, native fish access was improved to over 2,000 km of waterway. Despite the success of the program, Trust funding for individual HAG projects is capped at $40,000 per year and is primarily directed towards smaller projects involving on-ground works. Such funding is often not enough to tackle larger, more complex projects. Recently, the Trust approved a larger scale version of the HAGs called the Flagship Fish Habitat Rehabilitation Grant for which projects are able to apply for up to $400,000. The Flagship program has allowed for higher priority fish passage programs to be discussed and initiated that otherwise would have been delayed indefinitely. The Flagship program also value-adds to the existing HAG program, achieving a more holistic outcome for fish passage as will be discussed in one northern NSW catchment. This talk will detail the outcomes achieved by the HAG program and lessons learned along the way. The NSW Recreational Fishing Trust’s Habitat Action Grant Program and Flagship Fish Habitat Rehabilitation Grants are an excellent example of the NSW licence fee being directed back into the fishery to provide long term, permanent improvements to the waterways of NSW.