“Restoring fish passage and reconnecting waterways – it’s our passion”
Below is one of Tim’s videos featuring the culvert remediation project in the recently published “Lessons Learnt 8”.
There is some great underwater footage showing how fish navigate upstream utilizing the back-eddies and rest pools created by the flexible baffles.
For those that missed the write-up check it out here
https://www.doc.govt.nz/globalassets/documents/conservation/native-animals/fish/fish-passage/lessons-learnt-case-studies/lessons-learnt-008-installation-of-flexi-baffles.pdf
Jordie McDonald has completed a desktop GIS project highlighting the huge number of potential barriers to fish passage in the Northland Region of New Zealand.
The extent of the potential barriers is probably typical around NZ the rest of the world.
https://northtec.maps.arcgis.com/apps/MapJournal/index.html?appid=4342b312ac164e0aa83c9793936fa0b1
We will soon share a report on a large catchment where each site is visited and assessed. A “current status” is assigned to each in order to give a better picture of what is out there and what needs to be done to remediate. Enjoy!
The NZ Dept Conservation Fish Passage Advisory Group website has a number of Lessons Learnt describing different fish passage remediation projects.
Tim Olley spent over a year researching and putting together this comprehensive report highlighting the effectiveness of flexible baffles in a long, steep culvert.
We are planning to make a PowerPoint and/or video of this report at some point.
Enjoy.
Click here to view Lessons Learnt 8
We received heaps of thoughtful feedback from engineers and ecologists regarding the last mail-out, so we have summarized the comments below. The projects in question are typically the often steep outfalls from culverts or other structures, as opposed to stream restorations or realignments.
Treatment of rock armoring feedback:
This useful link to a very comprehensive Urban Storm Drainage Criteria Manual was shared by Iain Smith
https://udfcd.org/wpcontent/uploads/uploads/vol1%20criteria%20manual/08_Open%20Channels.pdf
Shane Scott has put together this short video showing some low cost fish passage remediation projects across North America.
Note the different configurations used to suit each site.
Also enjoy the great commentary with the Johnson Creek segment.
Contact Shane directly for more info – ph number at end of video.
Stop this disaster!
It is now common practice to use large, similar sized, rip-rap (boulders) to manage downstream erosion at structures.
Above is typical example of a recent culvert upgrade where extensive rock armouring has caused water to be sub-surface and spread over a wide area during most flows, making upstream migration almost impossible for most fish.
The rubber strip and rope were added afterwards to try to help with fish passage.
We need your help to share ideas on how to better provide fish passage while still meeting erosion control requirements.
– Discussion Paper-
The challenge – maintaining fish passage through rock armouring, especially during low lows.
Below is a concept that may provide passage for small fish, while still achieving erosion control.
A series of precast channels maintain a flow path that may be completely covered with large rocks, providing gaps remain between individual rocks.
Installation process
Points to consider:
– Channel design
– Installation
– Cost
– Durability
– Effectiveness (short and long-term)
– Planting
Restoring fish passage is great, but don’t forget about the habitat!
In natural environments, overhanging vegetation is important for shade, refuge and a food supply, but also helps fish migrate up along the edges of waterways.
This video shows a trial project funded by Nelson City Council, where PlanterPods and Flexi-baffles are working together to provide habitat and passage, along a section of heavily modified urban stream in New Zealand.
Please take a minute to watch this short video showing the effects of flexible baffles fitted to the invert of a box culvert.
This is a newly installed culvert (replacing an old smaller round one) under a public road in the Bay of Plenty, New Zealand.
It is hoped that over time, smaller bed-material will accumulate among the large rip-rap and between the baffles, creating a more natural habitat.
Also watch out for the juvenile galaxiid (whitebait) that were seen, just a few days after the installation, making use of the baffles to migrate upstream. Enjoy!
We hope you are all still healthy and making the most of the lock-down. The Fish Passage Action Team are taking the time to put together more resources to share with our growing audience.
Below is a link to a short video showing the challenges migrating elvers meet, even from their own species, when obstructed by man-made barriers such as perched culverts.
In nature, migrating fish will encounter delays due to natural features, however many have evolved to make mass migrations to ensure that at least some will get through to continue the breeding cycle.
Man-made structures and/or barriers interfere with this process and upset the natural balance of freshwater species.
It is not uncommon for other species, such as birds or rodents, to also take advantage of any delay in upstream migration. To grab and easy meal.
Enjoy.
Below is a link to a very interesting article posted by the NZ Dept of Conservation that discusses the importance of restoring fish passage to benefit all aquatic species.
Enjoy.
