This message is being reinforced in a DVD presented by television front woman Judy Bailey and produced by the Auckland Regional Council (ARC).
The DVD has been produced to promote greater awareness of problems caused by storm water – which is not treated like sewage – and sediment which flows into the waterways.
Building materials – such as zinc roofs and copper spouting, waste materials from cars – and waste from urban activities, such as factory yards, are some of the sources of the contaminants that build up in waterways.
Meanwhile, soil flowing off exposed land being developed, or has been deforested, is silting up the waterways.
Howick’s Mangemangeroa Estuary in Somerville Road and the Pakuranga Estuary are featured on the DVD, which presents the impact on eco-systems in non-scientific lay terms. It links the results of urbanisation with the shellfish, snails, worms, fish, rays and unique birds in Auckland’s waterways.
A sediment core from Mangemangeroa tells a story of the past 110 years and how sand has turned into mud, as well as an increase in heavy-metal content since urban development boomed in 1996.
Viewers are shown how cockles help oxygenate the sediment and transfer nutrients to the surface, moving like a bulldozer but unfortunately passing contaminants up the food chain as well.
A similar effect is shown in a Pakuranga Estuary core sample taken in 1996 showing the changes from 1958 when Pakuranga was predominantly rural, but by 1996 was 60 per cent urban.
Storm-water contaminants also affect other fish life and in turn sea birds which migrate to the Manukau Harbour and the Firth of Thames, for example godwits which fuel up after their 25,000km journey from Siberia and Alaska.
We are told by Ms Bailey the estuaries are crucial resources for young fish because they are used as nursing areas and for food. What happens to one part of the ecosystem matters to the whole, she says.
• Copies of the DVD are available free of charge to schools and community groups, and $5 (including postage) for individuals. Email marcus.ballantyne@arc.govt.nz or phone 366-2000 (ext 8689).
