The Bellevue City Council and Bellevue Downtown Association are split over how to route East Link light rail through the city’s central business district.

Both groups have agreed that tunneling is the only reasonable option, but questions remain about where and how to build the underground line.

The city council prefers a cut-and-cover plan known as C2T, which places the tracks below 106th Avenue Northeast.

One of the benefits of this alternative is that it provides a station in the Wilburton neighborhood that would serve the Hospital District and the Bel-Red corridor, which is slated for major redevelopments and higher density.

The BDA opposes C2T, saying it’s too expensive and disruptive. The group claims that constant construction from the project would bother over 1,000 residents for up to five years.

“Our members expressed grave concern that the C2T option would severely damage our downtown core,” BDA President Leslie Lloyd told the Sound Transit board of directors.

The BDA has asked for a deep-bore tunnel below 108th Avenue Northeast (the C3T alternative).

Cut-and-cover construction methods cause more surface impacts, whereas deep-bore tunneling takes place almost entirely underground.

“Folks seem ready to dismiss those concerns because they’re temporary,” Lloyd said. “Well, if you were a business that had to close your doors because your customers could not find you any more, that would be a pretty permanent impact.”

The C2T alternative also calls for demolishing and rebuilding the Bellevue Transit Center, which cost taxpayers $24 million to construct.

“The impact on transit use – for construction of a transit facility – seems unacceptable,” Lloyd said.

But all of the routing alternatives have their faults.

The city council has noted that C3T “has one of the highest displacements of businesses and employees, a large number of which would be medical clinics and offices associated with Overlake Hospital and the city’s hospital district.”

The BDA, denied by councilmembers, is taking its case directly to Sound Transit’s board of directors, which is expected to name a preferred alternative of its own on May 14.

A final routing decision will not come until after the final environmental-impact statement (EIS) is completed for the East Link project.

Sound Transit will consider all of the options until then, according to Don Billen, a project manager with the agency.

“It’s incumbent upon the board to keep an open mind,” he said. “They have to consider all the information from the final EIS before making a final decision.”

The city and BDA agree that Sound Transit’s at-grade alternatives would wreak havoc on local traffic and create a chokepoint for light-rail trains as they creep through the area at restricted speeds.

The transit package that voters approved last November does not include money for the construction of a tunnel through downtown Bellevue.

Lloyd urged the Sound Transit board to move quickly on approving a tunnel option so her group could get busy helping to nail down extra funds.

“From (the BDA board’s) perspective, building the system in a tunnel through Bellevue is the right thing to do,” she said. “And in this region, once we figure out what the right thing is, we have a history of coming together eventually to figure out how to get it done.”