Tuesday is the final day of early voting for Harris County’s proposed $2.5 billion flood bond, and as residents continue to trickle to the polls, the county clerk has downgraded his turnout estimate by a third.

When early voting began Aug. 8, Harris County Clerk Stan Stanart estimated 10 percent to 13 percent of the electorate would turn out, totaling between 230,000 and 300,000 voters. He lowered that estimate Monday afternoon to 170,000 to 180,000 voters, around 7.5 percent.

Put another way: that’s less than one vote per Harris County home or apartment building flooded by Hurricane Harvey. Stanart pleaded with Harris County’s 2.3 million registered voters to take the time to cast a ballot.

“There’s no lines at all. Just come in and vote, we’re waiting on you,” Stanart implored. “You get the government you vote for, so here’s your chance.”

RELATED: Search the proposed flood bond projects in your neighborhood here

According to the clerk’s office, 79,011 residents had cast ballots as of Monday evening, including 40,126 in-person voters and 38,885 mail-in ballots. More than 70 percent of early voters have been over the age of 65, the tallies show.

The polls are open 7 a.m. to 7 p.m. on Tuesday. Voters can find their polling place at HarrisVotes.com.

If approved, the bond would be the largest local investment in flood infrastructure since Harvey swamped the region a year ago.

It would fund at least 237 projects, including $1.2 billion for channel improvements, $401 million for detention basins, $242 million for flood plain land acquisition, $12.5 million for new flood plain mapping and $1.25 million for an improved early flood warning system.

Harris County Judge Ed Emmett said the bond is key to accessing more than $2 billion in federal matching funds. The judge, four county commissioners and flood control district engineers spent the summer crisscrossing the county at more than two-dozen public meetings on the bond.

Robert Stein, a Rice University professor who studies elections, said he expects most ballots to be cast during early voting. Though Commissioners Court members chose to hold the vote on the one-year anniversary of Harvey in the hopes of raising turnout, Stein said he is doubtful voters will rush to the polls on Saturday.

Some Republicans, including state Sen. Paul Bettencourt, have called for an end to summer elections on tax-increasing items, such as bonds, because they historically have low turnout.

Stein said poor voter participation should be cause for concern, but the date of the election was unlikely to change the public’s level of support for the bond.

“For the health and welfare and democracies, we should have more people voting,” Stein said. “But I don’t think the outcome would have been radically different if we had it in November.”

The bond has widespread support among members of Houston City Council and Harris County Commissioners Court, as well as local state legislators. A University of Houston poll found that 55 percent of respondents support the proposal.

The bond will lead to an increase in property taxes by 2 cents to 3 cents per $100 of assessed home value, according to county budget analysts. Those who are disabled or above the age of 65, and whose home is worth less than $200,000, would pay no additional taxes.