Progress on the Ruataniwha Dam stalled with the election of a new group of councillors last year, which shifted the 5-4 split away from supporting the dam. Before the year was out a moratorium had been placed on further activity relating to the dam, and HBRIC Ltd chair Andy Pearce had resigned.
This year Mr Newman also faced criticism for a costly regional council prosecution against the Hastings District Council relating to August's gastro outbreak, which was ultimately resolved out of court.
However Hawke's Bay Regional Council chair Rex Graham said there was "no direct pressure" on the CE to step down.
"But clearly there was always pressure on the issues with the new elected councillors," he said, citing the newly-elected councillors "not wanting to have more discussions on the dam which Andrew led".
"There was a bit of contention around water issues and stuff, but no pressure on him to resign."
Former chair Fenton Wilson echoed this, saying Mr Newman's resignation was "evolution not revolution".
In a statement Mr Newman said with all necessary groundwork to proceed with the scheme in place, the new group of councillors would soon make a final decision on the project, as well as setting a new direction to develop the council's strategic plan.
"This is a time of change at HBRC and time for a new direction, energy and vigour from the council's senior executive in assisting councillors with its agenda," he said.
Prior to the November election Mr Newman returned to his role as chief executive at the council, signing a two year contract.
Mr Wilson said while the maximum contract length was five years, there was "nothing sinister or startling" about the CE signing for a shorter period of time.
"That's just where it worked out on the day."
Mr Graham said the council and Mr Newman had "come to a mutual agreement on his future", but would not discuss any payout to be received by the CE.
Two other senior members of the council's current executive team are retiring in the coming months - including Asset Management Group Manager Mike Adye.
The other person had not announced their retirement yet.
The process of selecting a replacement would start immediately, with the successful candidate voted on by the nine regional councillors.