If viaduct's down, what will rise?

Myrtle Woldson, a 96-year-old Spokane heiress, owns one of the last big blocks of undeveloped land along Seattle's waterfront.

Her property between Seneca and Spring streets already is considered prime land but would be even more valuable if the Alaskan Way Viaduct gets torn down.

All along the waterfront, property values would increase up to 25 percent if the area is no longer cast in shadow by the 54-year-old roadway, a city study says.

The more desirable land is unlikely to produce a wall of new condo towers, however, next to where the viaduct now stands. Most of the properties are already developed, and historic protections and zoning restrict what can be built.

Still, there would be change. With a more attractive waterfront, rents likely would rise, buildings would get facelifts, and many would be re-oriented to take advantage of better views, new open space and an improved connection to the waterfront.

"Now most buildings have turned their backs on the waterfront," because of noise and the hulking underside of the elevated highway, said city Planning Director John Rahaim. Loading docks, but not ground-floor shops and restaurants, face the waterfront, he said.

A study by the Downtown Seattle Association, which is campaigning to replace the viaduct with a tunnel, predicts 2.5 million to 5 million square feet of new office, retail and residential space would be built if the viaduct went away.

The development likely would be dispersed over a large area — from the water up to Second Avenue, and from near the Olympic Sculpture Park all the way down to Starbucks headquarters in the Sodo neighborhood. It would occur on more than two dozen parking lots, by adding a few stories to existing buildings, and on an eight-acre tract near Safeco Field. There, developer Greg Smith plans four, 15-story residential buildings and six, nine-story office buildings — if he can get a zoning change, which he says is more crucial than what happens to the viaduct.

Large, undeveloped lots such as Smith's and Woldson's are not common, particularly near the central waterfront.

On one side of Woldson's property is a 13-story condo building; on the other is a seven-story office building. A block away is Seattle Steam, a private energy company that provides heat to about 200 clients such as Swedish and Harborview medical centers.

Seattle Steam wouldn't be inclined to move its network of pipes, said company President Stan Gent, and isn't going to sell its property.

Neither would some of the biggest landowners in the area. Five of the 10 largest owners are public entities — the Port, the city, the county, the state and the federal government — and it's unlikely they would sell much, if any, of their property.

Protections for historic buildings in the Pioneer Square and Pike Place Market areas also would prevent new developments from dominating the waterfront, Rahaim said.

Zoning rules are another impediment, he said. The rules prohibit condos and hotels on piers over Elliott Bay.

They also cap building heights at 160 feet, or roughly 15 stories, for properties just east of the viaduct. The cap could discourage owners from demolishing many buildings because it wouldn't prove lucrative to simply gain a few more floors, Rahaim said.

If a tunnel is built — now a political longshot — Mayor Greg Nickels has proposed tapping owners of properties near the waterfront for up to $250 million in extra taxes as part of a special district.

A preliminary study by the city reports that such properties would see values increased by a total of $400 million to $600 million.

The property values could increase similarly if the viaduct were replaced by surface streets and upgraded transit, rather than a tunnel.

"There seems to be the potential, but we haven't taken the steps of studying it yet," said Nickels aide Michael Mann.

Much would depend on whether putting so much of the viaduct traffic and noise on the street would become its own barrier to the water.

Some owners, such as Smith and Jonathan Diamond, president of Diamond Parking, say they will develop their properties regardless of what happens to the viaduct.

Still, Smith, who has contributed $20,000 to the anti-viaduct campaign for the March 13 election, said tearing down the viaduct would make his other properties that much more attractive.

"Existing real estate would benefit just because downtown would be a more vibrant place to live and shop, which equates to higher rents," Smith said.

As for Woldson, she has no plans to sell or develop her parking lot, said her real-estate adviser Don Spencer.

But it's not hard to imagine a deal she couldn't refuse.

"Their story may change dramatically because someone will make an offer that's so enticing," said John Taylor, policy director for the Downtown Seattle Association.

Bob Young: 206-464-2174 or byoung@seattletimes.com