Marom Creek Crossing
Before (pipe culvert barrier)
Marom Creek Crossing
During construction
Marom Creek Crossing
Fish friendly box culvert structure
Fish friendly crossings are waterway crossings that are designed to minimise impacts on native fish. Unfortunately, even ‘fish friendly’ crossings can impact some fish where debris collects in or on the structure or there are changes to the surrounding river system over time. It is therefore important to regularly assess road crossing structures and undertake routine maintenance to ensure the structures are working as they were originally designed.
The table below is taken from the Policy and guidelines for fish habitat conservation and management (2013 Update) and indicates DPIRD Fisheries’ recommendation for the most appropriate crossing type for the different classes of waterway in NSW.
| Waterway Classification | Minimum Recommended Crossing Type | Additional Design Information |
|---|---|---|
| Class 1 Major key fish habitat | Bridge, arch structure or tunnel | Bridges are preferred to arch structures |
| Class 2 Moderate key fish habitat | Bridge, arch structure, culvert[1] or ford | Bridges are preferred to arch structures, box culverts and fords (in that order) |
| Class 3 Minimal key fish habitat | Culvert[2] or ford | Box culverts are preferred to fords and pipe culverts (in that order) |
| Class 4 Unlikely key fish habitat | Culvert[3],causeway or ford | Culverts and fords are preferred to causeways (in that order) |
[1] High priority given to the ‘High Flow Design’ procedures presented for the design of these culverts—refer to the “Design Considerations” section of Fairfull and Witheridge (2003).
[2] Minimum culvert design using the ‘Low Flow Design’ procedures; however, ‘High Flow Design’ and ‘Medium Flow Design’ should be given priority where affordable—refer to the “Design Considerations” section of Fairfull and Witheridge (2003).
[3] Fish friendly waterway crossing designs possibly unwarranted. Fish passage requirements should be confirmed with NSW DPI.
It should be noted that there are additional factors that must be taken into consideration by those involved in waterway crossing design and construction, including public safety, social and budgetary constraints. Each crossing is therefore assessed by NSW DPIRD Fisheries on a case-by-case basis.
A piped causeway
Blocking fish passage in the Brunswick River
Bridge replacement
Improves fish passage by restoring the river channel
Causeway
Blocks fish passage at low-medium flows in the Manning River
Removed
Returning the site to natural conditions
Inadequate pipes
Causing water to jet out and block fish passage in the Mongarlowe River
Box culvert replacement
Reduce water velocities and allow fish to move upstream
Requirements of works in waterways
The restoration of fish passage throughout NSW waters is a key aspect of NSW DPIRD Fisheries' commitment to improving aquatic ecology and biodiversity.
The Fisheries Management Act 1994 includes provisions to ensure the maintenance and restoration of fish passage as part of the construction of new, or the modification of existing, in-stream structures. As such, works relating to a road crossing should follow guidance provided in NSW DPIRD Fisheries' Policy and guidelines for fish habitat conservation and management (2013 update) and may require a permit from NSW DPIRD Fisheries.