"Many of our rivers, lakes, streams and estuaries are in trouble and we need to respect and care for them much better in the future," he said. "We cannot put the financial burden of cleaning this up on one sector, we are all responsible.
"The task will require focused and courageous leadership from this council."
Although there were "still very difficult positions passionately held on certain key issues" by councillors, Mr Graham said he would respect their differing views.
After the meeting Mr Wilson - who had remained tight-lipped on whether he wanted to retain the role of chair - said he had nominated Mr Graham because he was passionate about the council having some cohesion.
"[Mr Graham's election] kind of reset the compass going forward," he said. "Rex had the numbers in the end, and it made sense to be constructive going forward."
There was also a unanimous vote to elect Mr Barker as deputy chair, after he was nominated by pro-dam Napier councillor Alan Dick, and seconded by returned Napier councillor Neil Kirton.
Although in support of Mr Barker in this role, Mr Dick said over the past term he had led a "parliamentary style opposition caucus", and a different approach was needed now Mr Barker was in a position of responsibility.
"I am confident that Rex and Rick will exercise that responsibility without fear or favour for not just the constituencies they were elected from, but for the whole of this diverse region that we have sworn allegiance to," he said.
Mr Barker agreed the deputy chair's role was to be a bridge between the chair and council, and to be a sounding board.
"We've got the best time to make a big difference and three years to do it," he said. "I welcome the challenge."
When asked, Mr Wilson said it was possible the election of the two Hastings councillors to leadership positions would change the direction of the council.
Change was also echoed in the first motions of new Napier Councillor Paul Bailey as a politician.
He moved to amend policy phrasing in a document before council from chairman to chairperson.
With this was carried, council chief executive Andrew Newman congratulated Mr Bailey, saying "that's entering a new world".
"We've just lurched forward twenty years."
Speaking to an agenda item, Mr Bailey later called for a discussion on the prayer which council has traditionally used to open each meeting.