Walaman Fishways can be used in a range of configurations at waterway sites to overcome the various types of hydraulic barriers to upstream fish passage at the site. This may involve using the Block Ramp fishway at the inlet or outlet of road culverts and causeways, or downstream of weirs or grade control structures. The Offset Baffle fishway may be used within culvert barrels and on culvert aprons and channelised sections.

The fishway component types (e.g. Offset Baffle, Block Ramp) are configured into integrated fishway facilities at these sites in order to:

  • provide suitable hydraulic conditions (velocity, shelter, flow depth, water surface drop, turbulence) for fish passage through the structure and adjoining waterway sections
  • provide flow continuity through all zones of the structure, a continuous fish pathway and suitable attraction flow for fish to locate and pass through the facility in response to flow
  • minimise obstruction to flow so as to not adversely affect flooding or to affect drainage functions and other utility values at the waterway structure
  • minimise adverse effects from debris accumulation and sediment deposition at the structure, maintain integrity of the waterway, and protect against erosion damage at and adjacent to the site
  • maintain natural flow regime and sediment processes in the waterway, protect riparian and instream habitat and provide connectivity for terrestrial, arboreal and aquatic fauna
  • provide for monitoring and maintenance of the fishway facility, provide for safety, and maintain amenity values at the waterway structure and fishway facilities

Design assessment will be required for each project in order to establish the fishway type and configuration appropriate for the waterway structure and the characteristics of the site. Planning and design for a project will usually involve the following for each site:

  • examine fish migration barriers at the structure
  • establish aquatic fauna connectivity goals and multipurpose design requirements
  • identify and evaluate fishway options
  • define configuration of fishway, other facilities and mitigation measures

Planning and design guidance for evaluation of fish migration barriers and design of fish passage facilities is provided in Culvert fishway planning and design guidelines (Kapitzke 2010).