'Poo-tracking' map shows you where Auckland's sewage ends up

A so-called 'poo tracker' has shown just where Auckland's sewage ends up - and it might make you think twice about going swimming at the local beaches.

Auckland City Council's SafeSwim website, which advises which beaches are safe from pollution for swimming, has released an animation showing sewage harbouring around the coast after heavy rainfall.

The animation shows what happened from May 10 to May 12, 2017 following a heavy downpour. Sewage can be seen streaming from points around the Waitemata Harbour, including Cox's Bay, Hobson Bay and Gentlemen's Bay.

The model represents bacteria-contaminated water, including e coli. The contamination harbours around the coast, moving in and out for days before dispersing. 

The animation is accompanied by a colour key showing that water depicted as green, yellow, orange or red means contamination levels are in excess of council guidelines. A considerable quantity of red water can be seen gathering around Herne Bay beach in particular.

Auckland Council's water manager Andrew Chin told RNZ that with wastewater comes "litter, the dental picks and tampons, the quite unmentionables that flow in".

The animation is part of the council's upgraded Safeswim website, which was launched in November 2017.