Richmond is bracing for the perfect storm on Election Day.

Election officials don't plan to use all of the city's 485 electronic WinVote machines on Nov. 4, despite predictions that potentially 80 percent of registered voters could show up at the polls to vote for president and other offices.

The reason?

Officials also must prepare for the likelihood that a runoff will be held six weeks later to settle the race for mayor.

A runoff would be held Dec. 16 if none of the five candidates wins the required five of nine council districts Nov. 4.

To make sure the city has enough handicap-accessible voting machines if there is a runoff, the Electoral Board decided yesterday to reserve 64 units -- one for each precinct -- for demonstration purposes on Nov. 4.

The plan drew no objection from candidates or the American Civil Liberties Union of Virginia. Candidates and election officials said it's a good idea to let new voters practice on machines before casting their ballots.

By holding back some units, Richmond will be providing an average of one voting machine for every 217 voters who are expected to turn out, instead of one for every 191 voters. Officials say that falls well within legal limits.

Registrar J. Kirk Showalter said she does not believe the change will lead to longer lines at the polls, but she acknowledged it's impossible to know how many people will show up at any particular time to vote in what figures to be a historic election.

Her office is bracing for about 82,000 voters -- an 80 percent turnout. That's about 10,000 more voters than the city had in 2004.

The precautions are needed, she said, because any machines used on Nov. 4 must be sealed if there's a recount or contested result. That kind of snag could make the machines unavailable until well after a runoff in the mayoral race, she said.

Election officials also are trying to line up an additional 62 optical-scanning machines to receive the paper ballots that would be used in a runoff.

Richmond has two scanners, and the others would need to be borrowed or rented. Showalter said finding available machines could be a challenge.

"Everybody else in the country is in the same situation. They're going to throw everything that they can at the November election," she said.

In addition, the city is looking for about 130 more election officers so extra lines can be provided to check in voters as they arrive at the polls. The positions are key because backups typically occur at those lines, not at the voting machines, Showalter said.

In the February presidential primary, Richmond had more than 41,000 voters -- about one-third more than expected -- "and the machines handled them beautifully," Showalter said.

"I'm hoping I'll wake up November 5 and all of my fears will be for naught, but I can't wait until November 5 to address them."

Contact Will Jones at (804) 649-6911 or wjones@timesdispatch.com.