[caption id="attachment_82657" align="alignnone" width="500"] Visitors are held at the door of the newly opened Graton Casino and Resort in Rohnert Park on Tuesday, Nov. 5, 2013, because the Fire Marshal limited the number of people who could enter at once. (image credit: Kent Porter, Press Democrat)[/caption]

ROHNERT PARK -- The $820 million Graton Resort & Casino opened its doors this morning to a throng of visitors from the Bay Area and beyond, as thousands were expected throughout the day have been snarling traffic in the area.

Originally slated for a 10 a.m. opening, the 340,000-square-foot, 3,000-slot machine casino opened an hour earlier in order to accommodate crowds that assembled on the western edge of Rohnert Park.

And the sprawling complex, owned by the Federated Indians of Graton Rancheria and operated by Las Vegas-based Station Casinos, was directed by the Fire Marshal to stagger entry into the property as it nearly reached capacity just hours after opening.

The casino is expected to release figures this afternoon on how many people showed up, but as many as 10,000 people reportedly are expected throughout the day.

Some 5,000 or 6,000 people are expected to be in the facility at a time, according to Joe Hasson, general manager of the casino.

Proponents of the casino have long maintained the economic boon it will provide to the region, including 2,000 jobs created. In addition, Sonoma County supervisors struck a deal that would provide at least $9 million annually to offset impacts of the project, plus as much as $38 million more per year if the casino is sufficiently profitable.

The city of Rohnert Park struck its own deal that will provide a 20-year, $200 million revenue-sharing contract with the tribe and casino.

Station Casinos is also expecting about $533 million in annual gambling revenues after the first two years, according to a 2012 report prepared for the Las Vegas-based company by The Innovation Group.

Opponents, meanwhile, contend the casino will have numerous adverse effects on the region, including increased traffic, environmental impacts and increased development, and blight associated with gambling.

A leading opponent, a group called Stop Graton Casino, or Stop the Casino 101, maintains the casino will result in increased development and have a negative impact on the county's open space. It also says increases in traffic and blight related to gambling will persist in and around Rohnert Park, resulting in an overall decrease in business.

The group said it filed a notice of appeal Thursday of Sonoma County judge Elliot Daum's ruling in favor of the casino being able to open. The group contends that the state didn't cede jurisdiction of the land to the tribe to be able to set up a casino.

Traffic backed up along Highway 101 up to the Wilfred Avenue exit to the casino in Rohnert Park before and after the casino opening. California Highway Patrol officials were on hand to monitor what they reportedly said was as many as 10,000 more vehicles than normal.