"If we don't have sensible water management in Hawke's Bay we may as well all hang up our boots," Mr Bostock said.
He said GAG's campaign had nothing to do with any negative third-party campaign and wanted to highlight its concerns "and effect change in a positive and fun way".
GAG is also behind red and white posters calling for a vote for change. The change involves GAG's preferred candidates: Rick Barker, Peter Beaven, Rex Graham and Tom Belford.
Mr Belford, owner of magazine Bay Buzz and environmental lobbyist, said there was no conflict between his environmental ideals and GAG's call for the lifting of water restrictions.
"We are all reasonable people," he said.
Mr Bostock said: "Apple trees, crops and vines don't pollute rivers."
"Cows do," Mr Belford said.
Mr Bostock said growers wanted clean rivers for future generations and that could be achieved with "sensible water management" along with prosperity.
"In a drought you can move stock or you can bring in supplementary feed. Denying trees water is absolute madness."
Hawke's Bay Regional Council chairman Fenton Wilson said the accusation that council did not engage with Twyford growers was "absolute bloody rubbish".
He said an agreement was reached with growers after "the realities around a consenting regime had been negotiated".
"Nobody thought we would have a one-in-70-year drought and be tested in the first year."
Lou Crasborn of Crasborn Group said "a disaster" had happened in Twyford. It was difficult to quantify he said, because it was not known if young apple trees had survived until spring growth arrived. Either way, he said, future production had been lost and council intransigence over irrigation during the drought was unacceptable.
"Just on our orchards alone we had 253,000 trees at stake and it just fell on deaf ears."
Mr Wilson said legislative guidelines forced council to focus on how water was managed.
Twyford growers faced challenges because compulsory metering meant their true water take would be known and they had asked for a greater allocation.
"That's when the likes of Fish and Game and others got involved and said, 'we don't want the minimum-flow limits to be any lower'."
He said any limit needed to be firm.
"The Twyford guys are saying, when we get to that limit in a one-in-70 year drought we've also got to have the ability to take more water. It's a fairly hard argument.
"It is not an easy discussion and it is certainly not being taken lightly on our end.
"There is a view that we were inflexible but so is the Building Act - you can't put up a building and say, when we get to the limits of stresses let's push it a little bit harder because it suits us and it makes more jobs and money.
"Instead of hanging boots up and stuff, why don't they come and see us and have an adult conversation - the door is open."
Twyford falls within the Hastings region which is represented by councillors Ewan McGregor, Kevin Rose, Liz Remmerswaal and Murray Douglas.
Mr Bostock said the council needed to swing its focus away from the Tukituki River catchment towards the Ngaruroro River's catchment, which had been ignored.
"There is where a vast amount of wealth is being created for Hawke's Bay. That's where all the money and jobs are being created.
"It has forgotten about the people of the region who are really creating the wealth and value on the Heretaunga plains. We are outraged at turning some of the best land in the world into a desert."
Mr Wilson said the irrigation scheme was largely being conducted by the council's investment company and overshadowed the extensive work council had done with groups such as the Twyford growers. Council actions were limited by regulations and resources.
"The community has a prosperity issue with water but there is also a quality issue."
He said there were many who were unhappy with council water policies, which showed a new appreciation for what had been taken for granted.
"It demonstrates there is actually a real value to water in New Zealand - that's starting to shine through."
Twyford growers were not the only ones to be hurt in the drought, he said.
"Everyone was hurting. The sheep and beef sector in particular had a hard run and as chair of the Hawke's Bay drought committee I can confirm it was hard going across the whole region."