ORANGE COUNTY

Bruce R. Clark has been appointed president and chief operating officer of Leighton and Associates, Inc. of Irvine. Clark, 44, had been vice president, chief financial officer and director of rock mechanics for the geotechnical consulting service. He will assume the new position Jan. 1. Clark will be responsible for the company’s day-to-day operations while chairman and chief executive officer F. Beach Leighton, who announced the appointment, will concentrate on strategic and long-range corporate planning.