Prince William County's embattled county executive resigned yesterday, agreeing to step down rather than risk dismissal by a Board of County Supervisors increasingly irritated by a management style many considered arrogant.

Bern Ewert ended nearly three years as the county's top manager moments after reaching a severance deal that gives him a year's salary--$126,800. Craig S. Gerhart, a 17-year county employee and one of Ewert's two deputies, was appointed acting county executive, effective immediately.

A headstrong manager whose blunt style antagonized several supervisors almost from his arrival in 1997, Ewert won points from many residents for urging controls on the sprawl that has overtaken the middle-class suburb 25 miles south of Washington.

His plan, which set aside the county's western end as a rural enclave and dramatically increased the money requested from developers to pay for needed new services, was approved by supervisors 17 months ago with strong public support. Its aim in part was to bolster real estate values flattened by overbuilding.

"I'm proud of my accomplishments," said Ewert, 57. "I'm quite delighted the value of property in this county has increased. But the time to go has come."

Ewert, a veteran municipal administrator, said he has not found another job but plans to consult or find another public-sector job from his home in Charlottesville.

"He's been the best thing that's happened to this county in a long time," said Martha Hendley, a slow-growth activist from Gainesville. "It's unfortunate the board can't keep up with him."

Ewert was hired on a 5 to 3 vote of the supervisors, some of whom expressed reservations about his communication skills from the beginning.

Ewert found himself at odds with supervisors as he charged ahead with plans without consulting them--denying them the opportunity to share the credit. He announced the slow-growth plan on his own.

His raise last year was conditional on attending a management class to improve his communication skills with the board and county staff, but Ewert insisted yesterday that his relationship with his staff was harmonious.

Supervisor Loring B. "Ben" Thompson (R-Brentsville), an outspoken opponent of the slow-growth plan, nonetheless credited Ewert yesterday with introducing "some really great initiatives on his watch," among them the restoration of the 19th-century Brentsville courthouse.

Said Supervisor Ruth T. Griggs (R-Occoquan), perhaps Ewert's biggest supporter on the board: "When you came, Prince William County was at a really precarious point. It needed just the right vision to put us on a positive path, and I think you did that."

The threat of dismissal hung over Ewert for months and probably would have come to a head in March, when a performance review was scheduled. But the board, with a new chairman who took office this month, decided a resignation would be smoother, several supervisors said.

Had he been fired, Ewert would have been entitled to a cash payout of approximately $63,000, plus vacation, sick days and other benefits. He decided to forgo the benefits and accept a higher cash deal.

Supervisors said they intend to conduct a search for a permanent replacement.