Experts trying to restore Christchurch's busted sewerage system have faced up to concerned residents about what happened when raw sewage was allowed to flow directly into the sea in the months after the February earthquake.
The Ōtakaro-Avon and Ōpāwaho-Heathcote in Christchurch are some of the most polluted in the region.
While the Avon has received a lot of attention since the Canterbury Earthquakes with $100 million going into a new promenade and cleaning up its water quality, it's a different story for the Heathcote River where raw sewage and industrial chemicals are still regularly found.
Niva Chittock reports.
For six weeks after the February 2011 Christchurch earthquake millions of litres of raw sewage - along with lots of liquefaction - poured into the Avon and Heathcote Rivers. A team of biologists quickly got to work to measure the impact of this catastrophe on life in the Heathcote River and as they tell Alison Ballance, they were surprised by what they recorded over the next few months.