"Winegrowers can live with some form of WCO in the upper Ngaruroro, and it aligns with our industry sustainability values, so we conditionally support it," he said.
However, this support was based on "multiple assurances" from the applicant, Fish and Game, about the intention of the WCO as it related to existing land-use activities, "and the assumption that the numerous problematical matters of detail in the draft order will be received".
His submission stated support was subject to confirmation that the wine-growing industry's needs were not significantly affected in the lower Ngaruroro, and allowing some water storage in the tributaries of the upper Ngaruroro to be considered.
Access to water played a "critical role" in the wine sector's success for irrigation, and frost protection. The wine sector is one of the largest intensive land-users in the region, with more than 5000ha in production – most of which is on the Heretaunga Plains.
"Wine is part of the heritage of Hawke's Bay, and we are the second-largest wine-growing region in New Zealand," Mr Harding said.
Although stage one of the hearing focuses on the upper Ngaruroro, the deputy chairman also told the tribunal a WCO on the lower river was thought to be inappropriate because it was not sufficiently flexible or adaptive to respond to community needs.
"The WCO fails to recognise and sustain the outstanding recreational and historical values associated with wineries and wine tourism in Hawke's Bay which are contributed to by the waters of the Ngaruroro," his submission read.
His submission outlined a range of reasons for opposition on the WCO in the lower part, including uncertainty around the impact on existing consents.
"It is essential for the industry to have certainty of takes, and restrictions on groundwater takes at times of low flow would be catastrophic for the industry. Accordingly the tribunal must consider the loss, over time, of the Hawke's Bay Wine industry.
"Based on the current information, viticulture may not be a viable land use for the lower Ngaruroro catchment and Heretaunga plains under this WCO."
An "active" participant in TANK, Mr Harding also said the association strongly supported this process, which they felt had been "unduly criticised". He advocated for the project needing adequate time to reach an "enduring and adaptive solution for the Heretaunga Plains".
Yesterday the special tribunal heard from representatives of Horticulture NZ, the Ngaruroro Irrigation Society, and the Twyford Co-op among others.
The WCO application was jointly filed by six applicants, and seeks to protect the Ngaruroro River, its tributaries and hydraulically connected groundwater to its lower part, and 7km of the Clive River.