Petaluma city leaders are working to shore up federal opposition to a potential casino on 277 acres south of city limits, land owned by the Dry Creek Rancheria Band of Pomo Indians.

Councilman Mike Healy, an attorney who has done legal work on behalf of opponents of the Graton Rancheria's Rohnert Park casino, this week asked his fellow council members to sign a letter to Sen. Dianne Feinstein, D-Calif., and Rep. Jared Huffman, D-San Rafael, enlisting their help.

The Dry Creek Rancheria has submitted an application to the federal government to take the tribe's six parcels along Highway 101 near Kastania Road into trust. While that move is necessary for approval of gaming activity, tribe representatives have said their plans don't include a casino there.

Local officials have been briefed on the tribe's plans for a housing and public sports complex on the rolling hillside land between Highway 101 and the Petaluma River south of Shollenberger Park.

Dry Creek Chairman Harvey Hopkins couldn't be reached Tuesday for further details on the tribe's trust application. A decision from the federal Bureau of Indian Affairs could take years.

The Dry Creek tribe operates River Rock Casino near Geyserville, but the planned November opening of Graton's Rohnert Park casino is expected to siphon off millions of dollars in River Rock's gambling profits.

The Petaluma-area location has widely been seen as an opportunity for the Dry Creek tribe to leapfrog Graton's casino to capture northbound customers.

The tribe has owned the Petaluma-area land since 2005, when it first submitted a trust application that included a casino. That application has since expired.

Healy said he wants to be able to trust assurances from the tribe that a casino isn't in the picture now.

But a draft of the letter highlights that potential, which is only possible if the property is taken into trust.

"The tribe has long had the ability to develop the property consistent with applicable local zoning," it states. "The only point of taking the property into trust would be an effort to override local zoning and other state laws."

Other council members said they would offer suggestions and revisions to the letter, which the council will discuss Aug. 5.

Healy said the Dry Creek tribe's plan for an on-site fire station is curious, noting that the San Antonio Volunteer Fire Department is less than a mile away.

"Thus, it is not alarmist to question the tribe's long-term noninterest in developing a casino," the draft letter states.

The land also has no water or sewer service, which would create tall hurdles to any major development.

The North Marin Water District, whose aqueduct provides Russian River water to other parcels in the area south of Petaluma, was to discuss the tribe's plans at its meeting Tuesday night.

District General Manager Chris DeGabriele said district policy precludes service to the tribe's land: "The property ... is not currently served by NMWD and we have no interest in serving said property."

Petaluma could offer to extend city utilities to the site with assurances that no casino would be built, although that would take voter approval. In a 2006 advisory ballot measure, Petaluma voters opposed a casino on the land by a 4-to-1 margin.

Healy said Tuesday the city could also offer recycled wastewater to the site to irrigate crops or vineyards, since the land is currently zoned for agriculture.

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