Second Waitangi sewage spill lasts 2 days

A burst pipe and a warning system failure have been blamed for another major spill of raw sewage in the Bay of Islands which has closed some oyster farms and put shellfish gathering off limits.

A leak of about 3000 cu m of untreated sewage flowed undetected for 48 hours from a faulty pipe in a pipeline running across a Landcorp farm block near the Waitangi River.

The flow of effluent is thought to have started on Saturday morning between Haruru Falls and a Far North District Council sewage treatment plant in the Waitangi Forest.

It ran over paddocks and through a wetland before discharging into the Waitangi River.

District council utilities manager Peter Johnson said the council was doing everything it could to remedy what he described as "a very serious situation".

Warning signs have gone up advising against collecting shellfish in the Waitangi estuary for 28 days and Orongo Bay oyster farms have been closed.

Northland Regional Council initial test results yesterday showed a faecal coliform count of 1700 downstream from the sewage discharge point in the Waitangi River.

Northland Medical Officer of Health, Dr Jonathan Jarman, said that generally a coliform count of more than 550 represented a significant health risk to anyone swimming in affected water.

It was also likely that shellfish in the river estuary would be contaminated by sewage.

Water quality monitoring officer Riaan Elliot said effluent was expected to ooze from the wetland into the river for several more days.

Dr Jarman said Northland Health was working with the district council to identify public health risks and ensure people know about them.

There is not thought to be any risk to people swimming at Paihia Beach.

The weekend spill is the second involving raw sewage in the Waitangi River area in less than two months.

A 700 cu m spill in February polluted water in the river estuary after sewage flowed into a stream and wetland area when a main sewer line ruptured between Haruru Falls and Waitangi.

A breakdown in monitoring a telemetry warning system, which is designed to quickly detect any pipeline or system failure, is being blamed by the Far North council for the latest spill continuing unabated for two days.

An investigation has started.