Burien took a major step forward March 30 toward annexing the southern portion of North Highline when the King County Boundary Review Board gave preliminary approval to the proposal.

The board is expected to formally approve Burien’s request on April 16 at their meeting in the Mercer Island Community Center.

“This is a historic moment,” Burien City Manager Mike Martin declared. “We have never been this far on annexation. I think we are on our way.”

If formally approved by the boundary board, an election will be held in the proposed annexation area on Aug. 18.

If voters pass the proposal, Burien staffers will prepare for annexation and welcome the new residents in March 2010, according to Martin.

Before the vote, Burien will hold several public meetings in North Highline. The next one is scheduled April 16 from 6:30-8 p.m. at Hilltop Elementary, 12250 24th Ave. S.

Other open houses are set for May 19 from 6:30- 8 p.m. at Salmon Creek School, 614 S.W. 120th St. and June 16 from 6-7:15 p.m. at Southern Heights Elementary School, 11249 14th Ave. S.

“We’re trying to do everything we can,” Martin added. “We want a big vote.”

He denied Burien officials picked the primary election date during the summer to suppress a large voter turnout. He said staffers want as much time as possible before March 2010 to get ready for the new area.

“The (election) date works well for a good transition plan,” Martin noted.

The city manager said the boundary board meeting held in Tukwila went well. He said board members were pleased with the mediation agreement worked out between Burien, Seattle and King County.

While Burien and county council members approved the agreement, Seattle lawmakers rejected it.

Martin noted boundary board members were “surprised and impressed” that several speakers favored Burien annexing all of North Highline.

Board members said they usually encounter speakers opposed to any annexation, according to Martin.

Burien officials have maintained that Burien is not able to take on all of the area at this time. Seattle or Burien could annex the northern portion at a later date. King County officials say the county cannot afford to keep providing services to urban unincorporated areas.

He said board members took a historical perspective in understanding that North Highline and Burien were considered a common area before Burien incorporated.

Martin added that state legislators are still considering a sales tax credit for cities annexing unincorporated areas, but “there is no assurances it will be adopted.”

The proposed annexation would extend Burien’s northern border to Southwest 112th Street in north Shorewood, except the area around the North Highline fire station at 12th Avenue Southwest. Burien’s city limits would then go south to South 116th Street, avoiding Evergreen High School and Pool as well as the Top Hat area.

Then, the line would head back north to South 112th Street in Beverly Park, extend to South 107th Street in Boulevard Park, taking in the Rainier Golf and Country Club, and end at Tukwila’s western border.