The government-waste question of the week is: Why is our state opening a viaduct museum, of all things, in Pioneer Square?

The answer: For the same reason you can get married at King County's new sewage-treatment plant.

The viaduct museum, with its dubious purpose and $490,000 price tag, comes at a time the state is said to be in its worst fiscal crisis since the 1930s.

"Isn't this Washington, where we're shortening the education year for our kids because of budget cuts?" reader Ellen Faber wondered in an email to me. "And yet, someone at the DOT found the funding to build a museum to honor concrete."

OK, that's selling it a little short. It is named Milepost 31 in honor of the viaduct, and it does tell the city's highway history.

But it's also more of an information center, for Pioneer Square and the tunnel project. What would be the only draw to me is the part that eventually will tell the technological story of tunneling (it will house a replica of the megamachine used to dig our Big Bore).

Still, her question is legit. Seriously, state of Washington? Why? And why now?

"If we didn't do this, we couldn't build the tunnel," Paula Hammond, secretary of transportation for the state, bluntly told me Tuesday.

When the $1.8 billion Brightwater sewage facility opened out near Woodinville a few months ago, it included an $8 million conference center with meeting rooms, lending library and dressing room for events such as weddings. You better believe people scratched their heads over that one, too. Why would a poop plant need any of that?

Obviously, it doesn't. Except for one crucial detail. The plant probably would never have been built without it.

That's because the center was part of a $140 million package of sweeteners, including parks, bike trails and sidewalks, to buy the support of 11 neighboring cities, counties, Indian tribes and a business park. In return for the goodies, the 11 pledged not to sue or make trouble for the plant.

The state says the same dynamic is at play with the tunnel.

With Pioneer Square, a historic district, "we are going to mess up their lives for four years with this project," Hammond said. "So we see this as a small price to pay to mitigate that."

It's just a cost of doing business.

The state Republican Party put out a statement calling it an "unbelievable" waste, proof the budget has hardly been trimmed of fat. Maybe so, but in the real world, is there an alternative? Just jam the project through, a la Robert Moses? Inviting lawsuits from anyone in the way?

"Ask yourself this: If your neighborhood was going to be under construction for years, what would you expect the state to do to help you?" said Leslie Smith, director of the Alliance for Pioneer Square.

Probably a lot more than a temporary info center. (I can see the T-shirts now: "Pioneer Square got bored, and all we got was this lousy museum.")

Smith said the state also has pledged to monitor historic buildings for damage, provide some parking, and — also likely to be controversial — pay for a marketing campaign promoting Pioneer Square. But the cost of the marketing can't be more than a few hundred thousand dollars, because that's what's left in that mitigation account.

It turns out that compared to Brightwater's neighbors, Pioneer Square is a cheap date.

"People can say it's all a waste, but these are the kinds of things you have to do on big projects," Hammond said. "There are things I don't always agree with either. But I have to do it to get anything done."

That's the thing about pork. It's really cooked up for the grease.

Danny Westneat's column appears Wednesday and Sunday. Reach him at 206-464-2086 or dwestneat@seattletimes.com.