Regional councillor Neil Kirton is issuing a challenge to Napier City Council to clean up its act after stormwater was released into Ahuriri Estuary last week.
Kirton, who is the regional council's representative on Te Komiti Muriwai o Te Whanga, the Ahuriri Estuary Committee, said the discharges weren't acceptable, but were becoming more common.
"My challenge to the Napier City Council is to produce a system which is not compromised by these sorts of discharges.
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"There is a viewpoint amongst some public servants that such discharges are within the tolerance, that is they are just part and parcel of a wastewater system in a city environment.
"Such discharges are not acceptable, they are not acceptable by the community, they are not acceptable by the tangata whenua.
"It seems that any significant storm event now results in this, very significant discharge."
NCC's director infrastructure services, Jon Kingsford, disagreed that the number of discharges was increasing, and said stormwater was discharged into the estuary at a lower rate than other councils, as proved by the Water NZ Benchmarking survey.
"Napier City Council has one of the lowest discharge rates in New Zealand for both dry and wet weather events," Kingsford said.
Kirton said NCC's investment into the stormwater and wastewater systems was not enough to account for population growth.
"When you delve into their plan you can see that the actual investment in infrastructure that will meet the requirement is not there."
Kingsford disagreed, saying Kirton's comments were ill informed.
"Napier has identified $8 million of investment in the stormwater network and $12.6m of investment in the wastewater network over the next 10 years that will deliver improvements in network performance and stormwater quality."
He said the regional council had not identified any forward-looking plans to improve estuary quality.
"In a recent estuary related committee meeting it was evident that to date Hawke's Bay Regional Council have not identified any forward-looking plans to improve the quality of the estuary."
However, he said that NCC was encouraged by the regional council's openness to collaboration, particularly in terms of future co-investment in initiatives to improve stormwater quality.
Representatives from the regional council disagreed with Kingsford's statement that the regional council did not have any forward-looking plans for the estuary.
Regional Council's group manager integrated catchment management, Iain Maxwell, disagreed there had been no future plans, and said it had been actively researching, and working to improve the health of the Ahuriri Estuary.
These plans included the TANK plan, Ahuriri Catchment Land Action Plan, hydrology research and invasive tubeworm control.
Issues with Napier's stormwater and wastewater systems are due to incorrectly installed pipes, which connect the two networks, allowing sewage to infiltrate the stormwater system.
Last Wednesday Napier's stormwater system became overloaded because of a period of above average rainfall.
Due to the risk of the sewage-contaminated water seeping into the streets, the city council decided to discharge the stormwater system into Ahuriri at 1am on Thursday.