SANTA ROSA -- Winzler & Kelly, the largest consulting engineering firm in the North Bay, today announced it merged with large Australia-based engineering, architecture and environmental consulting company GHD.

Winzler & Kelly's 100-person Santa Rosa office now is the Western U.S. operations center for GHD's U.S. operations, which now include Winzler & Kelly's seven California offices, one in Portland, Ore., and one each in Saipan and Guam as well as GHD's offices in Seattle, Phoenix and Irvine.

Top Winzler & Kelly executives now are overseeing parts of GHD's U.S. operations. President and Chief Executive Officer Iver Skavdal now manages operations center, Vice President and Chief Operating Officer Stephen Cox is director of operations for the Americas and Vice President and Chief Development Officer Marc Solomon is director of business development for the Americas. They now report to Don Graf, Irvine-based general manager of the Americas.

Other terms of the merger weren't disclosed.

"This merger benefits both of our firms," said Iver Skavdal, chief executive officer of Winzler & Kelly. "It allows us to offer increased innovation and efficiency to our clients and more professional development opportunities for our staff through a network of global resources, while also strengthening GHD’s offering in the Americas.”

Ranked No. 205 in revenue on trade journal Engineering News-Record's 2011 list of the top 500 design firms, 60-year-old Winzler & Kelly has more than 300 employees in 10 offices and recently expanded its Santa Rosa headquarters. GHD has 6,000 employees in more than 100 offices worldwide and ranked No. 204 among design firms this year, up from No. 227 last year.

Winzler & Kelly had $50.7 million in revenue last year, according the Business Journal's Book of Lists. Started in 1928, GHD had Aus$998 million in revenues last year.

GHD opened its first U.S. office in 2004 and now has more than 300 employees in 17 offices in the country, including one in Irvine.

“Winzler & Kelly brings us a tremendous talent pool that augments our superb East Coast operations in the USA, said Ian Shepherd, chief executive of GHD. "By joining with an established West Coast operation, GHD has expanded our service offering across the U.S., thus achieving a significant step in our growth strategy in the Americas."

The merger gives GHD now more than 70 services for U.S. water, energy, natural resources, environmental, building construction and transportation projects, Mr. Shepard said.

Richard Wankmuller, GHD’s executive in charge of the Americas operations, noted recent Winzler & Kelly projects such as the Middle Harbor restoration  at the Port of Oakland and the city of Santa Rosa’s highly green Utilities Department campus on West College Avenue.

Correction, Oct. 11, 2011: Winzler & Kelly had 10 offices before the merger.