RIVERTON — The City Council on Tuesday changed the way residents here will select their council representatives, and some residents say the change came without much warning.

The 4-1 vote changes the council from five at-large members to five members who each represent a specific district. It came after the agenda for the meeting was amended Friday, adding the districting item, which had not been on an earlier-posted agenda.

That late amendment had some residents questioning the council's motives.

"The thing that bothers me is that it wasn't on a regular agenda," said resident Steve Brooks, who had considered running for council but now lives in a district that won't be up for election until 2007. "It was like a last-minute thing."

City Manager Mark Cram said the change is effective immediately, meaning voters in two of the new districts will select their council members in November. The other three districts are up in 2007.

Cram said the change will improve municipal elections in several ways, allowing candidates to campaign in smaller areas, reducing costs and giving them a better chance to run among people who already know them.

He said it also will prevent a scenario in which one part of the city — and its specific issues and concerns — are disproportionately represented.

The item made it to the agenda at the last minute, he said, because city officials were working down to the wire with the county to ensure the districts were created with almost exactly equal populations.

"The city recorder was still working to tweak the numbers with the county as late as last Friday," Cram said.

He said the change has been in the works for months, and the city opted not to wait to put the item on a later agenda because the change will affect people's decisions on how and when to run for office.

"It won't be long before people will be declaring candidacy," he said.

But opponents say the change came too quickly and should have been studied longer, with more public input. Some suggest the issue should have gone before a citywide vote.

They also say it dilutes the residents' say in city government.

"It bothers me that they've taken the rights of the people to vote," Brooks said, because now residents will vote on only one council seat, not all five, as in the past.

Resident Andy Gibson worries the council made its decision to protect the current council members in the wake of unpopular votes allowing a controversial development that will include a Wal-Mart. A group of residents has pushed to have the zoning changes go before a public vote.