The Santa Rosa Police Department lost more than 150 years of experience this year as nine veteran and high-ranking officers retired, some with nearly 30 years on the force.

The retirements have paved the way for a slew of promotions and new hires, leading to changes within most if not all of the agency's departments, from violent crimes to communications and dispatch.

On Monday, the police department held one of the largest induction and promotion ceremonies in recent years in the Santa Rosa City Council chambers before a packed audience of familiar faces in Sonoma County law enforcement and their families.

"We've been planning this day for years," Police Chief Tom Schwedhelm said.

Fathers, wives and children pinned badges on three newly sworn officers as well as three sergeants, three lieutenants and a captain given new ranks.

The department has entered a period of "continuous recruitment and testing," the chief said. It has made conditional offers to two entry-level officers and is interviewing for three more positions.

And the turnover is expected to continue next year.

The result is a major shuffle on the force that has placed new managers at the helm of the patrol, violent crimes, domestic violence, narcotics, gang investigations and dispatch desks, among others.

With an eye toward this period of turnover when he became chief in 2009, Schwedhelm instituted "succession plans" for those expected to leave.

Still, "it will be a great challenge for the organization that it happened this quickly," Schwedhelm said.

Many among the 2012 retirees were, like Schwedhelm, part of a group that joined the force in 1983, including Capt. Gary Negri, Lt. Ben Harlin and Det. Bryan Reynolds.

Lt. Steve Bair also retired after a long career, including 19 years in Santa Rosa.

The other retirees include Officer Brennan Enos, Sgt. Steve Fraga, Officer Waid Allred, Officer Michael White and Officer Brian Bilyeu, who collectively spent 71 years with the department.

Although the retirements represent a loss of institutional knowledge, they also help the city grapple with significant pension debt. As of July 1 this year, new hires receive less generous pension benefits, part of a new contract approved in March.

Seven people were promoted from within the department.

New Capt. Craig Schwartz, who has more than 19 years experience and just returned from the FBI National Academy, now oversees the training and investigations bureaus.

The new lieutenants include Lance Badger, Rainer Navarro and Mike Tosti.

Tosti started with the Los Angeles Police Department, landed in Santa Rosa in 1991 and most recently led the narcotics team until becoming lieutenant.

Navarro, hired in 1992, led the gang unit and helped start a gang prevention program taught by officers in schools.

Hired in 1987, Badger most recently ran the motor officers and field evidence teams.

Three officers with between 12 and 16 years experience were named sergeants: John Cregan, Josh Ludtke and Ryan Corcoran.

Corcoran started at the Rohnert Park Public Safety Department and moved to the Santa Rosa force in 2007, distinguishing himself as a violent-crimes detective.

Both Ludtke was hired in 1998 and Cregan in 2005 and developed expertise in gang investigations. Cregan started with the Novato Police Department and Ludtke with Arcata police.

Among the new officers sworn in Monday was 2007 Cardinal Newman graduate Ken Ferrigno. Two others newly hired were Garrison Swartz of Livermore and Jeffrey Travers of Chico, who previously trained with Fish and Game.

Rachel Maconi, who started as an administrative assistant in 1999, will now supervise the communications/dispatch unit.

The department also hired longtime city employee Chelsea Green as a police technician and brought in an experienced dispatcher from Riverside County, Sarah Brian.

You can reach Staff Writer Julie Johnson at 521-5220, julie.johnson@pressdemocrat.com or on Twitter @jjpressdem.