DUBLIN -- The fate of a canyon coveted by both developers and preservationists could end up before Dublin voters on the November ballot.

The approximately 2,000 acres of rolling hills in Doolan Canyon north of Interstate 580 is one of the East Bay's last large swaths of rolling hills not yet designated for homes, businesses or open space.

Its future hangs in the balance. Environmentalists want the canyon as an open space buffer between Livermore and fast growing Dublin. A developer has approached Dublin with plans for a 1,900-home senior village in the canyon.

The East Bay Regional Park District has bought some 630 acres on the northern part of the canyon for a new park.

And some of the canyon's few rural residents aren't sure what to think of either plan, or how it would affect their desire to get a new water supply.

Now some Dublin residents want city voters to pass a measure creating a stiff new barrier to developing the area.

The residents are preparing for a signature drive to qualify a November ballot measure that would establish an eastern Dublin urban limit line, restricting growth beyond the eastern city limits.

Under the measure, any proposed development for Dublin beyond that line would require approval of city voters.

"This puts these development decisions in daylight so the community knows about them," said David Bewley, one of the campaign organizers. "Many people in Dublin are very concerned about the traffic and rapid development in our city, and there are thousands of more homes that are approved but not yet built."

Bewley's group submitted a petition notice to the city on Jan. 24 and hopes to begin collecting signatures in mid-February.

A Doolan Canyon resident for 35 years, Cassie Peterson talks about the needs of residents, especially for water, on Wednesday, Jan. 29, 2014 in Livermore,
A Doolan Canyon resident for 35 years, Cassie Peterson talks about the needs of residents, especially for water, on Wednesday, Jan. 29, 2014 in Livermore, Calif. A proposed ballot measure in November may make it much harder to develop the area and bring much need city water to homeowners. (Jim Stevens/Bay Area News Group) ( JIM STEVENS )

Bewley also was active in a successful 2000 ballot measure called Measure M that set an urban limit line for the west side of the city.

About 2,400 signatures are needed to qualify the measure for the ballot. However, the City Council could decide to adopt the new urban line on its own, making the citywide vote unnecessary.

Dublin Mayor Tim Sbranti said he hasn't taken a stand yet, but he is sympathetic to the idea of an eastern Dublin urban limit line.

"I think it's a good idea in concept, but we need to study the details," Sbranti said. The mayor said he told the ballot measure proponents that he wants to make sure the urban limit line doesn't hinder Dublin's ability to someday extend Dublin Boulevard to North Canyons Parkway, to provide a travel route that parallels I-580.

Bewley said his group worded the measure so as not to hinder the road extension.

Representatives of the Danville-based Pacific Union land development company could not be reached for comment on the proposed ballot measure and its effect on their plans for the 1,990-home senior community.

Doolan Canyon residents said last week they are not sure what to think about a Dublin ballot measure.

"We want water, and neither Dublin, Livermore or anyone else seems to offer us help with our problem as they continue to talk about what should or shouldn't be done with the land in our area," said Cassie Peterson, a Doolan Canyon resident.

Samantha Lanzone, operator of the Horizon East Equestrian Center in Doolan Canyon, said she hasn't taken a stand on the measure.

She said her family intends to continue running the equestrian center unless they got a buyout offer so generous they could reopen elsewhere. "We like it here," she said.

A leader at the Save Mount Diablo conservation group said his organization supports the petition drive as a way to protect open space and wildlife habitat.

"The water problem is a different issue than whether there should be housing built in Doolan Canyon," said Ron Brown, the group's executive director. "Pleasanton, Livermore and Alameda County all have urban limit lines. Only Dublin lacks one for the east side of the city."

Contact Denis Cuff at 925-943-8267. Follow him at Twitter.com/deniscuff