A senior manager with the St. Johns River Water Management District is calling the water district’s change in leadership “unprecedented” and a “shock.”

The manager is one of four who submitted resignations this week as the water district’s executive director also steps down.

Two of the four submitted letters announcing their resignation “in lieu of termination.”

Robert Christianson spent 24 years at the water district.

“I’ve been told that my performance has been exemplary and I’ve brought a lot to the agency, but that there’s a desire to have new leadership within the organization.”

The water district manages central and north Florida’s water resources.

Executive director Hans Tanzler stepped down Monday after announcing his resignation in March. He had been with the water district for more than three years.

Acting executive director Mike Register issued a statement saying it wouldn’t be productive to elaborate on the departures.