The Petaluma City Council has a strange bedfellow in its effort to prevent the Dry Creek Rancheria Band of Pomo Indians from building a casino on pasture land just south of the city limits.

Greg Sarris, tribal chairman of the Graton Rancheria, said his tribe opposes the possibility as well.

The Graton tribe is set to open its massive Rohnert Park casino and resort complex later this year, likely redirecting millions of gambling dollars away from Dry Creek's River Rock casino further north in Geyserville.

Petaluma opposed Graton's Rohnert Park casino because city officials expected it will bring a host of unwelcome — and expensive — impacts to Petaluma, including increases in crime and traffic and wear and tear on already-deteriorated area roads.

City Councilman Mike Healy, an attorney, provided much of the legal work to fight the Rohnert Park casino.

But Sarris has now joined Healy's lead in efforts against the Dry Creek tribe's potential casino development south of Petaluma. A casino there would likely siphon Bay Area gambling profits from the Rohnert Park casino.

The Petaluma City Council on Monday will consider a letter Healy has penned seeking support from the region's federal representatives to prevent Dry Creek's 277 acres along Highway 101 near Kastania Road from being taken into federal trust.

Although the Dry Creek chairman has said recently drawn-up development plans for the land don't include a casino, Petaluma leaders — and apparently Sarris — don't fully trust that assertion.

Chairman Harvey Hopkins didn't return messages seeking comment on the issue.

In comments last month, Hopkins said the tribe has dropped plans for a second casino, saying it would require taking on too much debt.

"Call his bluff," Sarris said of Hopkins' statements. "Have him make a statement that they will never develop a casino there. Have him make a legal and binding (memorandum of understanding) with the county and the city that should ... that land go into trust, it will never be used for the purpose of gaming.

"That will settle all this real fast," Sarris said.

In a memorandum with the county in 2008 leading to an expanded River Rock, the tribe agreed not to pursue a casino on its Petaluma property until at least 2016.

As shown in recent design drawings, the tribe's latest project calls for about 42 townhouses and condominiums for tribal members, six sports fields, an indoor sports facility, restaurant, convenience store, gas station, medical clinic and fire station.

The tribe also plans to develop a wetlands mitigation bank near the Petaluma River so the tribe could sell credits to developers who are required to offset the loss of wetlands for construction projects elsewhere.

Healy and other skeptics have questioned why the tribe needs to put the land into trust if it has no casino plans, or why it needs a fire station since there is an existing one less than a mile away.

He notes that once designated Indian land, it would not be subject to state laws or county zoning regulations, which designate the property for agriculture.

"We are concerned that the only reason for the tribe to transfer the property in trust to the federal government would be an attempt to circumvent these laws," states Healy's letter to Democratic Senators Dianne Feinstein and Barbara Boxer and Rep. Jared Huffman, D-San Rafael.

Healy also said that tribe's promises to not pursue casinos aren't enforceable, noting a Riverside tribe that said it was building community soccer fields as it was applying to have its land taken into trust.

"After it was taken into trust, the tribe changed course and built a parking garage for its casino," the letter states. "Similarly, the chairman of the Graton Rancheria told Congress in 1999 that his tribe had no interest in operating a casino; that casino is now under construction 10 miles to the north of us."

Petaluma leaders will discuss sending the letter at their 7 p.m. council meeting.

(You can reach Staff Writer Lori A. Carter at 762-7297 or lori.carter@pressdemocrat.com)