During a pro-waterfront tunnel campaign event last week, Mayor Greg Nickels announced an amendment had been submitted to the Washington Legislature to extend the deadline for finding money to replace the Alaskan Way Viaduct with a tunnel along the downtown waterfront.

Rep. Ed Murray, a native West Seattleite who now lives on Capitol Hill, introduced the amendment last week to extend a previous deadline for the city of Seattle to find more money to help pay for the project. Instead of April 1, Murray's bill would give the city until next January 1 to come up with the money.

About 110,000 vehicles per day use the Alaskan Way Viaduct. Traffic analysis indicates West Seattle accounts for about one-fourth of all those cars and trucks.

Replacing the aging Alaskan Way Viaduct with a waterfront tunnel - which would double as a new seawall - is the "preferred alternative" of the state and city departments of transportation. After studying the options for several years, they recommended a double-deck tunnel with two northbound lanes in one level and two southbound lanes in the other.

Engineers also are planning two northbound lanes and two southbound lanes on the Alaskan Way surface street. Cars and trucks would share both of the inside lanes of the arterial with streetcars.

Nickels wants to use replacement of the viaduct to rebuild much of Seattle's front porch. The problem is finding enough money.

Estimated to cost between $3.7 and $4.5 billion, the tunnel option is the most expensive of five alternatives studied. That's driven several elected officials to recommend building something cheaper. A new elevated viaduct would cost from $2.5 to $2.9 billion.

The Legislature has pledged about $2 billion because the viaduct carries a state highway, State Route 99. Much smaller contributions are expected from the Port of Seattle and the federal government as well as the city of Seattle.

At the waterfront open house, architectural ideas for what to build on the waterfront were displayed on easels set up around the room, but many of the concepts had been around a long time and some were even obsolete. For example, one showed the underground tunnel with the north and southbound lanes side by side. Engineers have since determined the tunnel would be less costly if the lanes were stacked one direction atop the other.

Development opportunities around the downtown waterfront were highlighted on a map, which showed the largest parcel as an oblong, irregularly shaped piece of land between the Alaskan Way Viaduct and Qwest Field. It runs from about King Street to Royal Brougham Way.

A new marina was proposed to be built south of Pike Street. A waterfront park near the stadiums was another architectural suggestion.

Protestors handed out brochures at the open house urging people to disavow the tunnel option and the makeover of the downtown waterfront. They argued for a new version of the elevated structure.

Meanwhile, the evening before last week's pro-tunnel event, Seattle City Councilman David Della told the Southwest District Council he favors building a new viaduct because it's affordable and can be built sooner. If the existing viaduct is vulnerable to a strong earthquake, Della wants to get on with its replacement.

"My concern is safety and doing something now," he said.

The mayor and other tunnel supporters are banking on getting about $800 million from a proposed regional transportation investment district which could be set up among King, Pierce and Snohomish counties, Della said. But he doubts the three-county district will ever be established.

Colman Dock is soon to undergo a makeover. One proposal at last week's open house showed a future ferry terminal on a small manmade island just off the waterfront. It would be connected to land by four or five ramps. Vehicles would board ferries from an underground parking garage within the island while vehicles farther back in line could wait in the parking lot at Qwest Field.

The real design of the new downtown ferry dock will rely on findings of environmental studies which are about to get underway, said Hadley Greene, spokeswoman for Washington State Ferries. The framework of those studies is to be established this spring. Public meetings are scheduled for April 20 and 25 at Colman Dock.

The ferry system has $225 million to replace the downtown terminal and the timber pilings upon which it is built. One of the goals of the new terminal will be to encourage private businesses to set up shop there so the ferry system can capture what Greene called "non-farebox revenue." Expect to see many more concessionaires in the new structure than are in the existing terminal, she said.

Tim St. Clair can be reached at tstclair@robinsonnews.com or 932-0300.