Just 16 miles north of Portland, near the tiny Washington town of La Center, construction is roaring on what will become -- by far -- the metro area's closest casino.

An army of workers has already completed the shell of the Cowlitz Tribe's planned $510 million resort. The 368,000-square-foot facility, named ilani, is set to open both its doors and its slot machines by spring 2017.

But a dice throw's worth of uncertainty surrounds the project.

An ongoing legal fight over land rights still threatens to derail it. And now, Oregon officials and some of the state's tribes have begun calculating just how much they'll stand to lose if the Cowlitz casino opens as planned.

State economists, for the first time, included potential fallout from a Cowlitz casino in their official revenue forecast: $65 million a year in lost Oregon Lottery funds that would otherwise go to schools, housing, economic development projects and state parks.

That's a fraction of the $1.2 billion the lottery contributes to the state's two-year budget. But a casino so close to Portland, drawing away players who might otherwise play video machines that drive so much of the lottery's revenue, "will definitely result in fewer available resources to spend," said Josh Lehner, an economist in the Oregon Office of Economic Analysis.

The Confederated Tribes of Grand Ronde, who operate Spirit Mountain Casino west of Salem, put their expected losses even higher, at more than $100 million a year.

"As a government that provides health, education and housing for its citizens, those impacts would be devastating," said Justin Martin, a Grand Ronde member and legislative lobbyist.

Sen. Mark Hass, D-Beaverton, chairman of the Senate's revenue committee, said the fight over the Cowlitz casino harked back to unsuccessful efforts in 2010 and 2012 to build a casino at Wood Village's Murray Kemp Greyhound Racing Park.

"That facility, just like the Cowlitz casino, would definitely be an economic drain," Hass said. "For better or worse, there's a segment of the population that likes gaming. If someone is going to build a mega-casino somewhere, that's where these people and their dollars will go."

Kara Fox-LaRose, president and general manager of the Cowlitz Project, argues market share for the Portland-Vancouver area is big enough to accommodate everyone.

"Being so close to the border, we have access to a great population center," she said. "But it's one we can all benefit from."

But Martin is still looking to the courts. He said he's surprised the Cowlitz are proceeding "full bore" with construction given the unresolved legal challenge.

Grand Ronde and other plaintiffs sued over the casino plan in 2010, saying the federal government erred earlier that year when it approved the Cowlitz Tribe's plan to take 152 acres in La Center into trust for a new reservation.

Similarly contentious issues have played out across the country as tribes try to get as close as possible to large, lucrative population centers. In doing so, however, some critics have blasted what they call "reservation shopping," where wealthy tribes try to build new Indian casinos on land with questionable ties to native America groups.

Had the application sought land even 15 miles farther north, Martin said, the Grand Ronde would not have sued.

"A casino that much farther north would still have had a huge impact on Spirit Mountain," he said. "But it would still have been within their ancestral lands. We consider the current case to be a classic example of reservation shopping."

The Grand Ronde are appealing a lower court's ruling that the land could be taken into trust. Closing arguments were delivered in the U.S. Court of Appeals in March. A decision is expected this summer.

Fox-LaRose said the Cowlitz tribe is confident enough in its stake to proceed with construction. The project is about 40 percent finished, she said, and will offer not just gaming opportunities, but also dining, retail, banquet and lodging accommodations.

She said she understands the Grand Ronde's consternation but added, "Our property will complement any existing offerings. Our location is far enough away that there's plenty of room for all of us to grow the market and benefit and continue to help the tribes."

As an economic counterbalance, Hass is suggesting that Oregon's nine recognized tribes join forces to explore building their own gaming facility in the Portland area.

Both Hass and the tribes acknowledge that a casino in Portland would still have the effect of slicing into both lottery revenues and other tribal gaming facilities in Oregon. But the effort, given Portland's sizable population base, could still prove beneficial, he said.

"There's an opportunity there," Hass said. "Whether that can actually happen, I don't know."

At this point, the prospects aren't promising.

"You'd still just be cannibalizing your own market," said the Grand Ronde's Martin, adding "most of this is still just pure speculation."

"Plus, Portland is in our ancestral territory," he said. "I'm just now sure how that would all work."

Beyond economic concerns, Oregon's tribes remain mired in their own disagreements.

The Confederated Tribes of the Siletz, for instance, are working with the Grand Ronde to develop a 16-acre commercial tract near Salem. But the Siletz are actively supporting the Cowlitz casino near La Center and have opposed other Grand Ronde plans.

Adding to the intrigue is the Grand Ronde's recent purchase of the Wood Village property. The tribe has not commented on whether a casino could be in the mix.

Evidently, the jockeying for land and gaming opportunities continues - in the metro area and just to its north.

"Our overall message is that this is something really significant," the Cowlitz's Fox-LaRose said. "It's an economic engine that will help improve the entire community."

-- Dana Tims

503-294-7647; @DanaTims