Wanganui District Council chief executive Kevin Ross has confirmed reports that identified shortcomings in Wanganui's wastewater treatment plant were never sent to Horizons.
Horizons relied on the district council's data to ensure the plant was working properly.
However with the information not forthcoming, Horizons said it just had its annual visual assessment to check the plant and up until recently described it as working well.
Mr Ross has taken ultimate responsibility for the reports not being forwarded to the regional council. The data was later provided as part of the annual plan.
Horizons' environmental protection team used that information to compile its own report which outlines significant shortfalls in the monitoring of Wanganui's wastewater treatment plant.
It covers October and November 2012 and notes that there were "numerous non-compliance" issues regarding the wastewater treatment plant.
Exceeding consent limits, faecal coliforms and suspended solids;
Not altering the frequency of sampling when non-compliance was identified;
No notification of change in sampling frequency;
No formal reporting of non-compliances to Horizons' environmental protection manager;
Mixing zone [located 1.6km out to sea] had not been checked for any suspended materials, bad smells, or change in clarity or colour of the water;
The collection of shellfish for monitoring was not at the required frequency;
The sea floor survey was not undertaken;
The annual report was late and had to be requested.
Reports with this information were written but not sent to Horizons, Mr Ross said.
The Horizons' environmental protection team issues a report about every two months on the plant. They are signed off by environmental protection manager Alison Russell.
Previous reports for 2012 note simply that the plant was "working well", based on annual visits to the wastewater treatment plant by Horizons staff.
Ms Russell said the site visit was a visual assessment only.
"We can assess the odour, for example. And at the time we last visited, in May 2012, there were no objectionable odours noticeable beyond the boundary of the wastewater treatment plant, nor had there been any complaints at that time."
Ms Russell said a true picture of how the plant was operating was only available once the Wanganui District Council provided the data assessment to Horizons as part of its annual plan.
"This showed that there were significant shortfalls at the plant."
She said Horizons and the council had met several times since then to discuss how the problems could be resolved.
She said Horizons' monitoring of the plant was standard.
Horizons issued the council with an abatement notice on January 9, after a stench had been wafting over Wanganui for about four weeks. The smell is not a breach of the council's consent, but is a breach of regional rules.
It has since been revealed by the council that the treatment plant was poorly designed and has never functioned properly. The council is currently working with wastewater experts Cardno BTO to determine the future of the plant.
In response to questions from the Wanganui Chronicle about the non-compliance, Wanganui District Council chief executive Kevin Ross issued the following statement.
"The key performance indicators in the Wanganui District Council's Annual Report have shown there are areas where the treatment plant is non-compliant.
"The ultimate responsibility for reporting to Horizons lies with Wanganui District Council's chief executive.
"Unfortunately, although the reports were prepared, they were not sent to Horizons. We have reinforced the required procedures to ensure this does not happen again."