In one of the more unusual municipal races in Utah, one incumbent defeated another Tuesday, but both will remain on the West Valley City Council.

Janice Fisher, who has two years left in her District 4 term on the council, lost her bid for the at-large seat held by fellow Councilwoman Margaret K. Peterson.The race had become more intense and somewhat acrimonious in the final days before the election, with the candidates and their supporters trading charges and countercharges. But both women promised to put the campaigns behind them and work together on a city council that was unchanged by Tuesday's election.

Councilmen Leland L. DeLange and Gordon W. Evans were unopposed in districts 1 and 3, respectively. The terms of at-large Councilman Gerald Wright and District 2 Councilman Duane R. Moss expire in 1993.

Up until an hour before the election filing deadline in September, it appeared that all three of the incumbents would be unopposed. But then Fisher stunned Peterson with her declaration of candidacy.

Peterson accused Fisher of using the at-large race as a rehearsal for a mayoral bid in 1993. While not denying an interest in the mayor's job, Fisher said her primary purpose was to represent all of the residents of West Valley. Mayor Brent F. Anderson has not said whether he will run for re-election in two years.

Peterson said she expected the race to be closer than it was. "I was prepared for the worst when I saw off-duty firemen (who supported Fisher) driving voters to the polls," she said.

"But hundreds of concerned citizens worked on my campaign, and that's what made the difference," Peterson added.