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Bob Rodgers’ photo of sediment discolouring the stream after rain last week.
The vigilance of locals has been invaluable in assessing the health of waterways such as Nukumea Stream and scientists would like to see more people involved as streams come under increasing pressure from development and population growth.
Nukumea Stream is one of the last remaining natural streams in Orewa and therefore very precious. It is home to a wide range of fish, including ‘declining’ species such as giant kokopu and inanga – as well as banded kokopu, freshwater crayfish, freshwater shrimp and shortfinned eels.
Freshwater scientist Sophie Tweddle, regional coordinator of Whitebait Connection, is among the experts who are extremely worried about the stream’s health. She has been working along the stream since last November on a project funded by the Hibiscus & Bays Local Board.
Her role has included identifying where the native inanga spawn, as well as involving local schools in learning about the stream.
She says in the short time she has been involved she has seen huge degradation of the stream with one issue being sedimentation from development sites, especially after heavy rainfall.
The bottom and lower banks of the stream are covered thickly in sediment. It is now time for the inanga, a whitebait species, to spawn and Sophie says the level of sedimentation threatens this process.
In addition, residents walking dogs have let them off the leash (which is not permitted in this area) and allowed them to run down the banks into the stream, damaging the streambed and banks where inanga lay their eggs.
Kensington Park resident Bob Rodgers volunteered to help Sophie. The stream passes through the subdivision and Bob keeps a close eye on it, using a water clarity tube and other equipment to record sediment levels, temperature and pH. His vigilance resulted in Council taking action last year to bring sediment controls at the Sunny Heights development up to standard.
Bob estimates he has seen around 10 major issues with runoff or pollution of the stream in the 15 months he has been monitoring it.
Council has dealt with six complaints about discharges into Nukumea Stream since March last year – the latest last week.
Sophie says the involvement of the community is key in looking after local waterways and she hopes that more people will step up to adopt their local streams.
She hopes that the local board will extend funding for the Nukumea Stream project for another year so that its health can be improved with things such as planting and events to increase awareness of the importance of the habitat it provides.
“If we don’t do something about it, there won’t be any whitebait left as streams are diverted and piped for development,” Sophie says. “We have to look after what we have left.”
Anyone interested in becoming part of a team to help Bob monitor Nukumea Stream can email Sophie – sophie@whitebaitconnection.co.nz
