NEW ORLEANS - There was more upheaval at the New Orleans Sewerage and Water Board on Monday with the resignation of outspoken board member Alan Arnold, the third board member to resign since flooding over the summer exposed widespread problems at the agency.

In a written statement, Arnold said he “had no choice but to resign” after Mayor Landrieu decided against appointing Arnold to be the chair of the board’s finance committee.

Arnold wrote that he was assured as recently as last week that the mayor had approved his chairmanship, only to learn Friday that Landrieu was going in a different direction.

“Only the technicalities of the appointment remained,” Arnold wrote. “It never happened. They mayor’s chief of staff called me Friday to report that the mayor had changed his mind. I told her that I had no choice but to resign.”

Arnold follows board members Kerri Kane and Scott Jacobs, who served as president pro tem. Both resigned in protest several days after Landrieu forced out the utility’s two top managers, Executive Director Cedric Grant and Superintendent Joe Becker.

With Arnold’s departure, the 11-person board is down to seven members, including recent mayoral appointee Stacy Horn Koch.

Arnold was one of two appointees from the city’s Board of Liquidation, which oversees the issuance and repayment of the city’s bond debt. Landrieu is expected to make a recommendation to that board on Arnold’s replacement.

Mayor Mitch Landrieu issued the following statement:

“Since first being appointed to the Board of Directors in 2008, Alan has brought his unique passion to Sewerage & Water Board, and I wish him all the success in his future endeavors,” said Mayor Mitch Landrieu. “As Sewerage & Water Board works to rebuild public trust, it’s imperative we have leadership in place that is constructive, forward thinking and even tempered. In the coming weeks, with the advice and consent of our City Council, we will appoint additional board members who together with existing members, will help restore the full trust of the people of New Orleans in this valued public water utility.”

The beleaguered agency remains on emergency footing with the board resignations on top of the forced departures of Grant and Becker. An interim management team of experts led by Paul Rainwater is scheduled to depart at the end of November, but no announcement has been made on who will take the reins after the team is disbanded.