‘Reverse waterslide’ at Allandale Stream helps fish swim upstream
A fish ramp installed near Living Springs is helping schools of inanga/whitebait and banded kōkopu swim upstream to restored habitats.
Before the reverse waterslide, fish were stopping their upwards swim due to a concrete weir.
Now, a steady flow of water guides them up a ramp and over the weir, so they can dip back into the upward stream and continue their journey.
A team effort brought to life
For nearly 50 years the Livings Springs Trust has been retiring farmland, planting riparian vegetation, fencing and regenerating forest to enhance biodiversity in the Allandale Stream catchment.
Local schools use the area as an environmental playground to help educate children about the importance of biodiversity.
In February 2023, the trust joined forces with us to improve fish passage past the weir.
Our rivers staff Tony Morrison and Marty Eder installed the six metre Mirradrain fish ramp at the Allandale Stream weir.
Banded kōkopu found upstream of weir in restored habitats after ramp was installed.
Limited fish before the ramp
Our central biodiversity advisor Martin Rutledge, who led the project and assisted the trust with resource consent, said before the ramp was built surveys showed only tuna/eel and one red finned bully was found upstream of the weir.
"There wasn’t the usual range of species that would be expected, such as inanga and banded kōkopu," Martin said.
Schools of inanga found after ramp
After the ramp was built, November 2024 surveys showed an increasing number of native fish and freshwater shrimp getting past the weir. Two species that had not been found before, inanga and banded kōkopu, were also recorded upstream of the weir.
Living Springs manager Denis Aldridge said for the first time people were reporting seeing schools of whitebait upstream of the weir.
This confirmed that the ramp was doing its job.
"It’s really great to know that our stream will be supporting more fish, and we really appreciate Environment Canterbury’s help to make that happen," Denis said.
Martin said he was amazed the ramp had worked so well.
"It’s been a rewarding project to be a part of and a great example of how we can improve our freshwater biodiversity."
What’s next
With the ramp in good working order, the number and variety of native fish in the stream are expected to keep increasing. There will be regular checks of the ramp, especially after floods, to clear debris and adjust sandbags as needed.
A follow-up survey is planned in summer 2026 upstream, including areas further up in the catchment, to monitor the progress of species like banded kōkopu.