SALEM — A former state lawmaker is behind thousands of automated calls to Deschutes County voters urging them to contact Sen. Tim Knopp with the hopes the Republican senator from Bend will vote against the Columbia River Crossing project.

In response, Knopp said, voters have flooded his office with calls of concern. The majority of whom, he said, are confused by the robocalls and wonder why he is voting in favor of a gas tax.

“They are leading people to believe this is a gas tax, or will lead to one,” Knopp said of the automated calls.

Knopp said he is undecided on the vote, but leaning in favor of the Columbia River Crossing project. The Senate is scheduled to vote Monday.

The House overwhelmingly authorized the $450 million in bonds the state will have to kick in for its share of replacing Interstate 5 between Portland and Vancouver. The state has struck a deal with Washington and will sell bonds only if its neighbor to the north also ponies up $450 million. The federal government would contribute $1 billion.

Opponents have voiced concerns about where the funding will come from. Proponents have discussed an overall transportation package in 2015 that could include tolling fees, or a gas tax.

“For me, there are two issues at play,” Knopp said. “Is there a replacement bridge needed? Is there an alternative to the (ideas) we have been presented with?”

He believes a new bridge is necessary and has yet to see an alternative.

Jeff Kropf, a former state representative from Sublimity who served in the House with Knopp in the early part of the decade, said he’s spent his personal cash to call as many as 100,000 voters in hopes the project fails. Kropf founded a nonprofit, which he runs, called the Capitol Watch Foundation; its mission it is to educate taxpayers on how their money is spent.

But, he said, he felt strongly enough about this project to dip into his personal coffers. He’s targeted three senators he sees as possible “swing votes” on the project.

In addition to Knopp, he’s calling constituents of Sens. Jackie Winters, of Salem, and Bill Hansell, of Athena, both Republicans. Winters said her office has received hundreds of calls in response to the robocalls, particularly from seniors. A 94-year-old woman called her office very upset.

“Think about it, you’re a senior … your hearing is not that good and you get this call,” Winters said.

Kropf said it’s important people know what an “unmitigated disaster” this project will be.

“Anybody who votes for this thing will be tarred with it for the rest of their political career,” said Kropf, who as a House member sat on the Transportation Committee.

The fact that the “boondoggle” of the project did not have to go through the Ways and Means Committee, Kropf said, sets a bad precedent.

“Ways and Means is where things get vetted for their ability to be financially sound,” he said.

The Oregon Department of Justice and Secretary of State had not received any complaints Friday.

“I will tell you, this was meant to scare the you-know-what out of seniors,” said Charles Richards, 70, of Salem, who received the call more than once.

Richards, who sits on the governor’s commission on senior services, said the call invoked “a sense of urgency.”

Knopp said he will vote in the way he thinks is “best for Oregon.”

“This is not a revenue raising bill, there is no tax increase,” he said. “The truth of the matter is every second or third legislative session there is a gas tax or road funding (package) introduced, and that would be the case regardless of whether this passed.”