NEW ORLEANS (AP) - More shake-ups are happening at the troubled agency that oversees storm drainage, sewer and drinking water systems in New Orleans.

  

Mayor LaToya Cantrell has announced that the interim director of the Sewerage and Water Board is being replaced, and three deputy directors have resigned.

  

The new interim director, introduced at a Monday news conference, is retired Coast Guard Rear Adm. David Callahan. He will oversee the transition to a permanent executive director, Ghassan Khorban, who takes over next month after heading the Milwaukee Department of Public Works.

  

Callahan becomes the fourth interim director since flash flooding last August revealed numerous problems with the pumping system that drains city streets. More recently, problems with a new billing system led to many residents disputing bills, which affected the agency's revenue.