Ahead of this, the Environmental Protection Authority released information on the submissions received for the application, which reveals more about who has weighed in on the application, and what is driving their support, or opposition of it.
Of the 388 submissions received - 122 opposed the application, and 119 supported it.
While slightly more submitters opposed the WCO, more wanted the tribunal to recommend the WCO be granted - 89 compared with the 73 who wanted it declined.
Another 70 submitters wanted it recommended the WCO be granted, with changes.
Two major topics stand out from the variety of themes in the submissions - 69 per cent mentioned commercial and industrial operations, while 46 per cent appealed for alternative processes, rather than the WCO.
The 266 submissions on commercial and industrial operations discussed both positive and negative impacts of the WCO on businesses, now and in the future.
"The majority of submitters ... raised strong concern of the impact this proposed WCO would have on their businesses and the economy", which included that jobs could be lost, and that Hawke's Bay's economy could suffer.
"Other submitters expressed a view that conservation of these rivers should be given priority over economic demands", which included that more environmental protection was needed, and that healthy rivers had an economic value.
The majority of the 177 submitters who mentioned alternative processes rather than the WCO felt the Hawke's Bay Regional Council-led TANK project was a better tool.
Views were split amongst the 143 submitters who mentioned culture and heritage - WCO supporters discussed the importance of enabling the river to retain or replenish its mauri, and the spiritual health of nearby communities.
However tangata whenua raised concerns over consultation, and that food, wine, and production values were integral to the Heretaunga community's cultural identity.
Other topics mentioned included water quantity and quality, aquifers, water sports, and ecology.
