CEDAR RAPIDS, Iowa - As promised, a grass-roots citizen group on Tuesday turned in more than 4,032 signatures, which will force a special election on March 6 to ask voters to extend the 1-percent local-option sales tax in Cedar Rapids for 10 years to raise revenue for flood protection on both sides of the Cedar River.

In fact, the citizen group — called CREST for Cedar Rapids Extended Sales Tax — turned in more than 4,900 signatures and will turn in some additional ones to the Linn County Board of Supervisors yet this week to put the signature total over the 5,000 mark, CREST committee members Brad Hart, a Cedar Rapids attorney, and Mike Butterfield, a project civil engineer in Cedar Rapids, said Tuesday afternoon.

Butterfield said he was optimistic that voters will approve the extension on March 6 because CREST’s petition calls for a 10-year tax extension with all the Cedar Rapids revenue going to flood protection, a change from an unsuccessful effort on May 3 for a 20-year extension with money going to flood protection, roads and tax relief.

“My optimism really stems from, number one, the amount of success we’ve had in collecting signatures,” Butterfield said. “And more than that, this time around really answers a lot of the concerns that the community at large had last May. This is a shorter time frame and it’s dedicated to flood protection on both sides of the river.”

Ben Rogers, chairman of the Linn County Board of Supervisors, on Tuesday afternoon said the board now will review and count the group’s signatures with the expectation of setting a March 6 vote by next Tuesday.

On sales-tax questions, contiguous cities vote as a block, and so Cedar Rapids, Marion, Hiawatha, Robins and Fairfax all will vote on March 6, with elected officials in each of the jurisdictions deciding how their community will use the tax revenue. Voters in unincorporated Linn County and in the Linn County portion of Walford also will vote.

All other jurisdictions in the county either extended the sales tax for 20 years on May 3 or have had the tax in place without an end date.

Linn’s Rogers called the CREST signature effort “herculean,” noting that the group amassed nearly 1,000 more signatures than needed in pretty quick fashion.

“It took a lot of volunteers and a lot of hard work to get to where they are,” said Rogers, a Cedar Rapids resident. “And I really appreciate a citizen group taking charge of something so important as flood protection.”

Rogers said he will vote for the tax extension because the city needs flood protection and the city must provide some of the money for the system if it is to convince state and federal lawmakers to help with the cost.

CREST’s Butterfield said more than 50 people helped collect signatures in a campaign that began in midsummer.

Voters in the metro voting block defeated the ballot measure for a 20-year tax extension on May 3 by 221 votes out of 31,932 votes cast.

A vote by the Cedar Rapids City Council, which represents the majority of residents in the county, was sufficient to require the Linn supervisors to set the May 3 vote.

After the May 3 vote, Cedar Rapids Mayor Ron Corbett said any new vote on a tax extension would need to be prompted by a citizen petition drive. The drive needed to collect 4,032 signatures — 5 percent of the total of those who voted in Linn County during the 2010 general election — to force the vote.

The existing local-option sales tax in the metro area expires on June 30, 2014.