Mr Belford said he remained open-minded, but skeptical, about the dam project.
In a Talking Point opinion piece published in today's Hawke's Bay Today, Mr Belford said he had "reluctantly" resigned from Transparent Hawke's Bay, an organisation he co-founded, even though he saw no conflict.
"I resign only because I want no confusion in his [Mr Wilson's] mind or anyone else's between the views I express on the dam as a councillor and any views THB might express on the matter going forward," he said.
Mr Wilson said the resignation did not resolve the issue, which was that Mr Belford had a responsibility to declare potential conflicts of interest.
"Because of a lack of transparency, now that he's resigned from Transparent Hawke's Bay it makes it worse. If it didn't mean anything and it wasn't worth declaring, why does resigning from it fix the issue? I don't think it does," Mr Wilsons said.
The president of Local Government New Zealand, Hastings Mayor Lawrence Yule, said this week that a council could potentially face a legal challenge to a decision it made on the grounds that a councillor was "pre-determined" on an issue as a result of lodging a submission on it.
In turn, the individual councillor could conceivably be pursued for the costs resulting from that legal challenge, he said.
In an email to Transparent Hawke's Bay members and supporters, the organisation's chair, Pauline Elliott, said Mr Belford's resignation was received "with much regret".
She said Mr Belford "inspired a constant challenge around transparency of local government process and access to reliable information. We all know that, in his role as councillor, he will continue to do the same."